"PLANT FOR TREATING A SHEET FIBROUS MATERIAL DESTINED TO PRINT, PARTICULARLY DIGITAL PRINT, AND AN ASSOCIATED PROCESS OF TREATING SAID SHEET FIBROUS MATERIAL"

FIELD OF THE INVENTION

The present invention refers to a plant for treating a fibrous material having a sheet shape destined to print, for example digital print; further the invention refers to a process of treating said sheet fibrous material destined to print. The plant and the associated process, object of the invention, find application for treating a sheet fibrous material, for example formed by or comprising a fabric and/or a non-woven fabric, before a process of printing on at least one side of said sheet. Generally but in a non limiting way, the invention can be applied in the textile or in the knitted fabrics or in the non-woven fabrics industry for preparing a printing material, for example a digital-type printing material .

STATE OF THE ART

As it is known, the conventional printing - in other words the one using cylinders or printing silk-screen frames - and the digital-type printing - in other words the one using one or more nozzle printing heads - are technologies used for applying inks or paints defining motifs, patterns, colorations on different types of sheet materials such as, for example, paper, fabrics, non-woven fabrics, fell, etcetera.

The fabrics, non-woven fabrics, or other fibrous materials having a laminar structure destined both to the conventional and digital prints are subjected to a series of preparing steps, before being printed, and to one or more steps of finishing the fabric, after the printing step.

More particularly, it is noted that a suitable pre- treatment of at least the fibrous material surface, before the printing process, causes the ink to be deposited in the desired way and place, and to be suitably fixed to the fibrous material itself. For example, the fibrous material to be printed can be treated with substances afterward adapted to enable to suitably fix the printing colours : these treatments are for example performed with alkali-based or acid-based (according to the type of ink afterwards applied) , thickener-based, antimigrant-based and/or wetting agents-based substances. These substances and the associated pre-treatment processes are known and used in the textile field, and - generally - vary as a function of the fabric and type of the printing ink. The pre- treatment enables the ink drops to be fixed on the fibers of the material to be treated without forming marks and spreading around in a uncontrolled way: the preliminary step of treating the fabric therefore ensures a good colours yield and a suitable definition. Specifically, in the digital printing processes, a suitable pre-treatment of the material to be printed, has a crucial importance. Actually, in the digital printing, jet heads having a plurality of nozzles having a small ink passage opening are used: in this situation, it is virtually impossible to directly add additive to the ink because this latter could become, for example, too much viscous, which would prevent to control the ink passage through the heads, or could get chemical- physical features which are not easily manageable by the systems controlling the same digital heads . Due to this reason, the material to be printed is previously treated as hereinbefore described and, only after, is subjected to the digital printing. Specifically, the at least superficial application of the above described pre- treatment substances is typically done by immersion in or by spraying liquid forms, which eventually leave the material to be printed wet or at least moisturized. Therefore, before the printing step and after the additives application, it is provided a step of drying the material to be printed.

A first known type of an apparatus for pre-treating and digitally printing on sheet materials (fabrics included) , is described in the patent EP1577101B1 (and in the associated patent application US 2005-206711A1 ) disclosing an apparatus provided with a closed loop movable conveyor belt on which the sheet material to be printed can be fixed. The apparatus has a pre-treatment substance applicator, a pre-treated material dryer, destined to only partially dry the material itself, and a printing device. Lastly, downstream the printing station, the apparatus has a further drying device and then a station for steam-fixing the printed sheet. The described apparatus is not configured for completely drying the sheet material to be printed. Moreover, in order to correctly treat the sheet (applicating the additives and drying the sheets), it is necessary that the same is kept at a low motion speed which considerably slow the overall printing process.

The patent application FR1385197A instead describes a fabric drying device wherein the fabric to be dried is placed along a serpentine path. One or more fans produce air flows inside the bends formed by the fabric to be dried. It is noted that the fabrics is guided through the serpentine path directly by idler rolls, in other words, the fabric is completely unsupported during the step of moving and drying the same. Consequently, the fabric does not have the dimensional stability during the drying step, which could compromise the possible following step of printing the fabric with an unavoidable reduction of the resolution and therefore of the print quality. Moreover, the fabric is substantially left free between one idler roll and the following one, so that it is consequently difficult to evenly dry all the fabric surface. Moreover, it is noted that both sides of the fabric are directly in contact with the idler rolls surface so that the homogeneity of surface pre-treatment performed before the drying step is compromised, also on the side destined to the print. This means that the presence, on the same fabric, of areas having different drying degrees and different pre- treatment degrees negatively affects the quality of the following printing step.

A further example of the drying device is described in the USA patent US1996020: the apparatus herein described comprises a casing in which a support belt operates which is caused to pass in an alternate way around a idler rolls placed at different heights in order to define a serpentine path forming a plurality of apposed bends. Inside the bends there are operative openings configured for directing air against the sheet material: the air moving on the sheet material enables to abut this latter on the support belt and, at the same time, helps dry it. For making easier the air passage, the support belt can have a plurality of through holes . Also this latter approach is not devoid of disadvantages . De facto, it is noted that the fabric sliding inside the casing is simply abutted on the support belt and is thrusted by air flows: therefore although the belt acts as an anvil element, the sheet material is therefore substantially capable of freely moving, having in this way the possibility of being subjected to uncontrolled warps which can compromise the uniformity both of the previous pre-treatment step and the drying step. It is observed that the possible presence of holes on the conveyor belt causes an uneven drying which forms points having a high air passage - at holes where the sheet material can be more dried - and points of low air passage - in the unperforated area of the belt - where the drying will be less marked. As hereinbefore discussed, every disuniformity in the treatments before the printing step determines a consequent reduction in the printing step quality.

OBJECT OF THE INVENTION Therefore, an object of the present invention consists of substantially solving at least one of the disadvantages and/or limitations of the previous approaches .

A first aim of the invention consists of providing a plant and an associated process enabling an efficient treatment of sheet fibrous materials, for example fabrics, knitted fabrics and/or non-woven fabrics, in order to provide the sheet material in optimal conditions for the printing, particularly the digital printing. Specifically, it is an aim of the invention to provide a plant and an associated process enabling to evenly dry the sheet fibrous material, particularly a previously wet fibrous material and/or impregnated with pre-treatment substances such as for example thickeners and/or antimigrants additives.

A further object of the invention consists of providing a plant and an associated process of pre-treating sheet fibrous materials which enable to move the fibrous material during the drying step without compromising the uniformity of the drying step itself.

A further object of the invention consists of providing a plant and a process of treating sheet fibrous materials - optionally provided with a system or a pre- treatment step with substances such as for examples thickeners and/or antimigrants additives - which can be installed with reasonable operating costs and by offering a high productivity.

One or more of the above described objects which will better appear in the following description are substantially met by a sheet fibrous material treatment plant and an associated pre-treatment process according to one or more of the attached claims .

DEFINITIONS

In the following description and in the attached claims, the listed terms take the meanings specified in the following .

^■ Ink: a mixture formed by a dispersion of pigments or by a solution of dies in an aqueous or organic medium destined to be transferred on surfaces of different materials for obtaining one or more prints; it is understood that are also comprised clear inks and paints .

^■ Fibrous material: a material consisting of fibers of a variety of types, for example a fabric, a non-woven fabric, a knitted fabric, or combinations of one or more of said supports .

^■ Sheet fibrous material: a fibrous material as hereinbefore defined, formed in a structure having two dimensions (length and width) having both a markedly prevalent extension with respect to a third dimension (thickness) . The term "sheet fibrous material" means both a fibrous material in discrete sheets having limited lengths (for example the formats AO, Al, A2, A3, A , etc.), and continuous bands exhibiting a marked length which can be supplied by a roll on which the sheet material is reeled or can come from an in-line printing step. In any case, the sheet fibrous material, herein described, exhibits two sides, or main surfaces, on at least one of which it is provided a print.

■Digital printing: a printing using one or more nozzle printing heads for applying inks defining motives, patterns, colorations, etc., on sheet materials. The printing heads can be movable transversally to the sheet material advancement direction, in order to cover the overall width to be printed, or can be transversally stationary, when the heads width is equal to the printing width, in other words the fabric.

^■ Treatment liquid: comprises one or more liquid compounds, or one or more compounds dissolved or dispersed in a suitable liquid phase, having the function of pre-treating at least the surface or surfaces of the sheet fibrous material, destined to receive one or more prints. The compound/s can be from a natural and/or synthetic sources (polymers and/or copolymers) and having one or more of the following functions: antimigrant, thickener, modifier of the surface tension, acidity modifier, hydrophilicity modifier, drying accelerator, fixing enhancer. The liquid phase can be aqueous or polymeric.

^■ Treatment foam: comprises a dispersion of a gas in a liquid; moreover, the foam may have colloidal-dispersion characteristics. The foam may be obtained by directly blowing high pressure gas in a liquid or using foaming agents .

In one embodiment, the treatment foam comprises the treatment liquid as described above and, optionally, one or more additives as: foaming agents, wetting agent and viscosity modifier agent.

Foaming agents are known to the skilled person and for instance comprise surfactants, for example cationic, anionic, amphoteric, non-ionic surfactants; for example, alkyl betaines, in particular laurilamidopropilbetaine may be used. Suitable wetting agents include for example silicone derivatives. Viscosity modifying agents include for example, modified or replaced cellulose and poly (meth) acrylics acids and their salts, such as ammonium salts, preferably: hydroxyethylcellulose , carboxymethylcellulose and cellulose dimethylpropane sulfonate .

The composition forming the treatment foam may for example comprise:

^treatment liquid in a percentage comprised between 5% and 75%, preferably between 10% and 60% by weight with respect to the total weight of said composition,

^at least a foaming agent in a percentage comprised between 0.2% and 5%, preferably between 0.4% and 2% by weight with respect to the total weight of said composition,

^ ater as it lacks to reach 100%.

If present, the wetting agent is present in the composition of the treatment liquid used to produce the foam in a percentage ranging between 0.001% to 5%, preferably from 0.01% to 1% by weight with respect to the total weight of said composition. If present, the viscosity modifying agent is present in the composition of the treatment liquid used to produce the foam in a percentage ranging between 0.001 to 5%, preferably from 0.01% to 1% by weight with respect to the total weight of said composition.

Means usable to produce the foam of the invention is well known to the skilled person and many different means are commercially available. For example in case of use of direct blowing of high pressure gas (air) in the liquid medium and/or in case of use of foaming agents, the means for producing foam may be a mechanical stirrer, a conventional mixer, or a foaming machine.

The density of the treatment foam is greater than 0.005 g/cm ³ , preferably between 0.01 g/cm ³ and 0.3 g/cm ³ ; the density of the foam was determined by placing a specified volume of foam in a graduated laboratory cylinder of known weight, by determining the weight of the foam and calculating the density by the known volume and weight. The expansion ratio of the treatment foam, defined as the ratio between the weight of the liquid and the weight of an equal volume of foam prepared with the liquid, is between 2:1 and 6:1, preferably between 3 : 1 and 5:1.

The average diameter of the cells of the foam in accordance with the invention is greater than 0.05 mm, preferably comprised between 0.08 and 0.5 mm. The average diameter of the foam cells was measured by placing a foam sample on a microscope slide, by observing under a microscope at a magnification of 32 times, and counting the number of cells in an area of 6.77 mm ² . In particular, the average diameter D of the cells measured in mm was determined by the equation:

D=2/Vn* [ ( 6.77 ) (Liquid Density-Foam Density) /cell number] ^Λ 1/2 Preferably the treatment foam may comprise :

^treatment liquid in a percentage comprised between 5 and 75% by weight with respect to the total weight of the foam, such a treatment liquid may comprise:

o at least one anti-migrant agent, preferably selected from alginates, cellulose derivatives, in particular carboxymethylcellulose, hydroxyethylcellulose , acrylic (co) polymers, xanthan gum, gum arabic and guar gum, and/or

o at least one agent for controlling the pH, preferably selected from sodium bicarbonate, sodium carbonate, ammonium sulfate) , ammonium tartrate and citric acid, and at least one hydrotropic agent, preferably selected from urea and thiourea,

^at least a foaming agent in a percentage between 0.2 and 5%, preferably between 0.4 and 2% by weight with respect to the total weight of the foam,

^ ater as it lacks to reach 100%.

SUMMARY

The aspects of the invention are described in the following .

In a 1st aspect, it is provided a plant (1) for treating a sheet fibrous material (T) destined to the ink- printing, the plant (1) comprising:

- at least one conveyor belt (2) movable along a closed path and having an exposed surface (S) configured for receiving the sheet fibrous material (T) , at least a portion of the closed path of said conveyor belt (2) defining an operative section (5) for conveying the sheet fibrous material (T) wherein this latter sheet fibrous material (T) is at least temporarily constrained to the conveyor belt (2),

- at least one drying station (6) placed at least at a portion of said operative section (5) and configured for at least partially drying the sheet fibrous material (T) passing at the drying station.

In a 2nd aspect according to the preceding aspect, the plant (1) comprises at least one applicator (13) configured for placing, on at least one first side (Tl) of the sheet material (T) and/or on the exposed surface

(S) of the conveyor belt (2), an adhesive material (M) capable of at least temporarily constraining the sheet fibrous material (T) to the conveyor belt (2) .

In a 3rd aspect according to anyone of the preceding aspects, the operative section (5) of the conveyor belt

(2) is configured for defining a plurality of bends placed at the drying station (6) .

In a 4th aspect according to anyone of the preceding aspects, the drying station (6) comprises a casing (8) defining at least one treating chamber (9) inside which said portion of the operative section (5) extends.

In a 5th aspect according to the preceding aspect, the casing (8) comprises an inlet port (10) configured for constantly enabling a section of the conveyor belt (2) entering the treating chamber (9) to pass, and an outlet port (11) configured for constantly enabling a section of the conveyor belt (8) exiting the treating chamber (9) to pass, and wherein the length extension of the portion of the operative section (5) inside the treating chamber (9) is greater than the maximum distance between the inlet port (10) and the outlet port (11) of the casing ( 8 ) .

In a 6th aspect according to anyone of the preceding aspects, the drying station (6) comprises a casing (8) defining at least one treating chamber (9) inside which said portion of the operative section (5) extends, the casing (8) comprising an inlet port (10) configured for constantly enabling a section of the conveyor belt (2) entering the treating chamber (9) to pass, and an outlet port (11) configured for constantly enabling a section of the conveyor belt (8) exiting the treating chamber (9) to pass.

In a 7th aspect according to anyone of the preceding aspects, the operative section (5) of the conveyor belt (2), is configured for defining a plurality of bends placed at the drying station (6) .

In an 8th aspect according to anyone of the aspects from

4 to 7, the plurality of bends is defined inside the treating chamber (9) .

In a 9th aspect according to anyone of the aspects from

5 to 8 , the bends extend all along the operative section (5) inside the treating chamber (9) .

In a 10th aspect according to anyone of the preceding aspects, the plant (1) comprises at least one inlet station (7) configured for receiving the sheet fibrous material (T) and placing a first side (Tl) of this latter sheet in contact with the exposed surface of the conveyor belt (2) .

In an 11th aspect according to anyone of the aspects from 2 to 10, the applicator (13) is configured for laying a continuous layer of the adhesive material on the first side (Tl) of the sheet fibrous material (T) and/or on the exposed surface of the conveyor belt (2) . In a 12th aspect according to anyone of the aspects from 2 to 11, the applicator (13) is configured for laying a continuous layer of the adhesive material, only on the exposed surface (S) of the conveyor belt (2), having a width at least equal to the sheet fibrous material (T) width, or to a width of a portion to be printed of the sheet material .

In a 13th aspect according to anyone of the aspects from 2 to 12, the applicator (13) comprises at least one selected in the group of:

- a spreading blade (37) placed transversally to the conveyor belt motion and spaced above the same conveyor belt (2),

- a spray dispenser (38) spaced above the conveyor belt (2),

an applicator roll (39) with an associated respective blade regulating a thickness of the adhesive material (M) deposited on a lateral surface of the applicator roll, this latter being placed with the rotation axis transversal to the conveyor belt (2) motion and with a lateral surface spaced above the conveyor belt (2),

a drum (40) placed with the rotation axis transversal to the conveyor belt motion and with a lateral surface spaced above the conveyor belt, the drum (40) exhibiting a hollow interior destined to receive a predetermined quantity of adhesive material (M) and being provided with a predetermined number of nozzles or slits for dispensing the same adhesive material,

- a distributor (41) comprising a tank (42) configured for receiving the adhesive material (M) , the tank (42) exhibiting at least one dispensing nozzle (43) defining an outlet of the tank (42), the nozzle (43) extending transversally to the conveyor belt (2) motion all along the width of this latter, the distributor (41) comprising one or more pushers, for example one or more toothed wheels, placed inside the tank and configured for supplying the adhesive material (M) from the nozzle (43) .

In a 14th aspect according to anyone of the preceding claims the adhesive material (M) comprises a liquid or foam composition.

In a 15th aspect according to anyone of the aspects from 10 to 14, the inlet station (7) comprises at least one pressure member (14), particularly a pressure roll, configured for receiving the sheet fibrous material (T) and pushing it against the exposed surface (S) of the conveyor belt (2) for enabling to be at least temporarily fixed between the conveyor belt and the sheet fibrous material.

In a 16th aspect according to the preceding aspect, the applicator (13) is interposed between the pressure member (14) and casing (8) or wherein the pressure member (14) is interposed between the applicator (13) and casing ( 8 ) . In a 17th aspect according to anyone of the aspects from 10 to 16, the casing (8) extends from the inlet station (7) to the end of the operative section (5) of the conveyor belt (2) so that said treating chamber (9) receives both the inlet station (7) and operative section .

In a 18th aspect according to anyone of the preceding aspects, the drying station (6) comprises one or more generators (12), optionally each formed by a fan or a compressor, configured for generating one or more respective gas flows adapted to hit at least a portion of the sheet fibrous material (T) constrained, particularly fixed, on the conveyor belt (2) .

In an 19st aspect according to anyone of the preceding aspects, the drying station (6) comprises a plurality of gas distribution channels (24) evenly distributed along at least a portion of the operative section (5), each of said distribution channels (24) being configured for blowing a gas, particularly continuously, in the direction of the exposed surface (S) of the conveyor belt (2) for progressively drying the sheet material (T) sliding on the operative section (5) .

In a 20th aspect according to the preceding aspect, the distribution channels (24) are configured for blowing a gas at least at the bend operative section (5) . In a 21st aspect according to the aspect 19 or 20, each of said distribution channels (24) is configured for blowing a gas on the operative section (5) inside the treating chamber (9) .

In a 22nd aspect according to anyone of the aspects from 19 to 21, the distribution channels (24) are connected to said one or more generators (12) .

In a 23rd aspect according to anyone of the aspects from 5 to 22, the plant (1) comprises at least one intermediate idler member placed inside the treating chamber (9) and active at the operative section (5) of the conveyor belt (2), the intermediate member being placed, in an operative condition of the plant (1) itself, at a height different from the one of the inlet port (10) and/or outlet port (11) of the casing (8) in order to define at least one ascending section (15) and descending section (16) of the conveyor belt (2) .

In a 24th aspect according to anyone of the preceding aspects, comprising a plurality of intermediate idler members active at the operative section (5) of the conveyor belt (2), the plurality of intermediate idler members comprising a first group of intermediate idler members aligned along a first row (Fl), and a second group of intermediate idler members aligned along a second row ( F2 ) , said first and second rows of intermediate idler members being placed, in an operative condition of the plant (1), at different heights in order to define, on the operative section (5), a plurality of ascending sections (15) and a plurality of descending sections (16), particularly the first row (Fl) being placed at a height greater than the height of the second row ( F2 ) .

In a 25th aspect according to the preceding aspect, wherein along each of said first and second rows (Fl, F2 ) a plurality of intermediate idler members are placed, and wherein at least said portion of the operative section (5) of the conveyor belt (2) is guided in an alternate way around an idler member of the first row, and around an idler member of the second row immediately following in order to provide said portion of the operative section with an ups-and-downs trend defining said bends.

In a 26th aspect according to the preceding aspect, the intermediate idler members of the first row (Fl) are uniformly spaced from each other along the advancement direction of the conveyor belt, and wherein the intermediate idler members of the second row ( F2 ) are uniformly spaced from each other along the advancement direction of the conveyor belt, the idler members of the first row (Fl) are offset with respect to the idler members of the second row (F2) with respect to an advancement direction (A) of the belt itself.

In a 27th aspect according to the aspect 25 or 26, wherein the minimum distance between two adjacent intermediate idler members of the first row (Fl) is substantially equal to the distance present between two adjacent intermediate idler members of the second row (F2) .

In a 28th aspect according to anyone of the aspects from 24 to 27, at least a portion of the plurality of the intermediate idler members is placed inside the treating chamber ( 9 ) .

In a 29th aspect according to anyone of the aspects from 4 to 28, the operative section (5) of the conveyor belt

(2) crossing the casing (8) longitudinally separates the treating chamber (9) in a first and second half-chambers

(22, 23), wherein the first half-chamber extending above the exposed surface (S) of the conveyor belt (2), and the second half-chamber extending below an inner surface

(I) of the conveyor belt (2) opposite to said exposed surface, the drying station (6) being configured for directing a gas flow inside the first half-chamber (22) towards the sheet fibrous material (T) temporarily constrained, particularly fixed, to the exposed surface

(S) of the conveyor belt (2) . In a 30th aspect according to anyone of the aspects from 24 to 29, each portion of the conveyor belt (2) extending between two following intermediate idler members of the first row (Fl), and an intermediate idler member of the second row (F2) comprises a respective descending section (16), a respective ascending section (15) and a respective lower junction section (33) interposed between and connected to said descending and ascending sections, said descending, junction and ascending sections (16, 33, 15) of each said belt portion (2), delimiting a respective bend and being configured for receiving the sheet fibrous material (T) by making the latter to face the inside of said respective bend, the drying station (6) being configured for emitting a gas inside a plurality of said bends.

In a 31st aspect according to anyone of the aspects from 3 to 30, the drying station (6) comprises - for each of a plurality of said bends - at least one respective distribution channel (24) placed inside the bend defined by the conveyor belt (2), the distribution channel (24) being configured for emitting a gas flow towards the sheet fibrous material (T) carried by the exposed surface ( S ) .

In a 32nd aspect according to the preceding aspect, the distribution channel (24) vertically extends substantially all along the extension of the descending and ascending sections (16, 15) of the conveyor belt (2) .

In a 33rd aspect according to anyone of the aspects from 19 to 32, the distribution channel (24) extends all along the width of the conveyor belt.

In a 34th aspect according to anyone of the aspects from 19 to 33, the drying station (6) comprises an inlet conduit (25) connected to one or more generators (12) and to the distribution channel/s (24), said inlet conduit (25) being laterally placed to the conveyor belt (2) and extending for at least a main portion of, optionally all, the height extension of the distribution channel (24), said conduit (25) being configured for delivering a gas flow to the distribution channel and providing the gas flow with a transversal direction, particularly normal, to an advancement direction of the conveyor belt (2) .

In a 35th aspect according to the preceding aspect, the inlet conduit (25) comprises:

- an inlet opening (26) adapted to receive a gas flow from one or more generators (12) and substantially placed at the top of the treating chamber (9),

- one or more service openings connected to the distribution channel (24) and lateral to the conveyor belt (2), the service opening/s being configured for delivering a gas to said channel (24),

- a gas passage section at least partially decreasing from the inlet opening (26) advancing towards along a development of the inlet conduit itself.

In a 36th aspect according to the preceding aspect, the/each distribution channel (24) has a gas passage cross-section at least partially decreasing advancing, from the service openings, along the development of the inlet conduit (25), transversally to the conveyor belt (2) .

In a 37th aspect according to anyone of the aspects from 19 to 36, the drying station (6) comprises a single distribution channel (24) placed inside each bend.

In a 38th aspect according to the preceding aspect, the inlet conduit (25) is connected and delivers gas, from one or more gas generators (12), to the one or more distribution channels (24).

In a 39th aspect according to anyone of the aspects from 23 to 38, the distribution channel (24) comprises a first and second emitting walls (27, 28) respectively facing the exposed surface (S) of the descending (16) and ascending sections (15) of the conveyor belt (2), each emitting wall (27, 28) comprising a plurality of through openings (29) configured for enabling to emit a gas towards the sheet fibrous material (T) .

In a 40th aspect according to the preceding aspect, the through openings (29) are distributed on each emitting wall along rows transversal, particularly normal, to the advancement direction of the conveyor belt (2), optionally, the rows of the openings (29) are, according to an operative condition of the plant, substantially horizontal .

In a 41st aspect according to the preceding aspect, the through openings (29) are uniformly distributed on the emitting wall in order to substantially define a regular array of openings .

In a 42nd aspect according to anyone of the aspects from 19 to 41, the/each distribution channel (24) comprises at least one flap (30), optionally wherein a deflector for each through opening or for each set of through openings is provided, configured for directing at least a portion of the gas flow exiting the channel itself and for generating one or more respective gas flows having one component, particularly a main component parallel to the exposed surface (S) of the conveyor belt (2) .

In a 43rd aspect according to anyone of the preceding aspects, the conveyor belt (2) is configured for having a width greater than the maximum width of the sheet fibrous material (T), said conveyor belt (2) comprising at least one first and/or one second dragging portion (17) configured for transversally emerging from the opposite longitudinal sides of the sheet fibrous material ( ) .

In a 44th aspect according to the preceding aspect, the plant (1) comprises at least one dragging device (20) active on at least one of said first and second dragging portions (17) of the conveyor belt (2) and/or on an inner surface (I) of the belt itself opposite to the exposed surface (S), said dragging device (20) being configured for moving the conveyor belt (2) without contacting the exposed surface of the belt itself.

In a 45th aspect according to the aspect 43 or 44, each intermediate idler member comprises a first and second guiding portions (18, 19) respectively placed at the first and second dragging portions (17), said first and second guiding portions (18, 19) being only active on said dragging portions (17) of the conveyor belt (2), particularly said guiding portions (18, 19) of the intermediate idler members being configured for not contacting directly the sheet fibrous material (T) temporarily fixed on the conveyor belt (2) .

In a 46th aspect according to the preceding aspect, the dragging device (20), optionally comprising at least one chain or belt, is movable along all the load operative path of the conveyor belt (2), said dragging device (20) engaging and moving the guiding portions (18, 19) of a predetermined number, optionally all, of the intermediate idler members of the plant (1), the dragging device (20) with the guiding portions (18, 19) of the intermediate idler members being configured for moving the conveyor belt (2) at least along said operative section (5) by acting on the dragging portions (17) .

In a 47th aspect according to anyone of the aspects from 24 to 46, each intermediate idler member of the first row (Fl) comprises an idler roll or drum (21) configured for directly contacting an inner surface (I) of the conveyor belt (2) for guiding it along at least a portion of the operative section (5) .

In a 48th aspect according to anyone of the aspects from 5 to 47, the ratio of the length extension of the operative section (5) defined inside the treating chamber (9) to the maximum distance between the inlet port (10) and outlet port (11) of the casing (8) is greater than 2, particularly is comprised between 3 and 20, still more particularly is comprised between 3 and 10.

In a 49th aspect according to anyone of the preceding aspects, the conveyor belt (2) - at least at a longitudinal continuous band of the exposed surface destined to receive said sheet fibrous material - is devoid of through openings crossing the thickness of the belt itself.

In a 50th aspect according to anyone of the preceding aspects, the conveyor belt (2) comprises at least one continuous layer of a waterproof material defining the exposed surface (S) and capable of providing the exposed surface (S) , along a view normal to a motion direction of the belt, with a continuous and preferably rectilinear outline.

In a 51st aspect according to anyone of the preceding aspects, the operative section (5) of the conveyor belt (2) has a perimetral extension - measured along the advancement direction of the belt itself - greater than 20 m, particularly greater than 30 m, still more particularly greater than 50 m.

In a 52nd aspect according to anyone of the aspects from 4 to 51, the operative section (5) placed inside the treating chamber (9), has a perimetral extension - measured along the advancement direction of the belt itself - greater than 15 m, particularly greater than 30 m, still more particularly greater than 50 m.

In a 53rd aspect according to anyone of the preceding aspects, comprising at least one control unit (34) active on the conveyor belt (2) and on the drying station (6), said control unit (34) being configured for :

- commanding the movement of the conveyor belt (2),

- commanding the drying station (6) and determining an emission of drying gas directed at least at said operative section (5) of the conveyor belt (2) .

In a 54th aspect according to the preceding aspect, the control unit (34) is configured for controlling a motion speed of said conveyor belt (2) and for controlling said drying station (6) so that a same section of the sheet fibrous material (T) is subjected to said gas emission for a time comprised between 30 and 240 seconds, particularly between 30 and 120 seconds, still more particularly between 30 and 90 seconds.

In a 55th aspect according to the aspect 53 or 54, the control unit (34) is configured for moving the conveyor belt (2) at a speed greater than 20 m/min, particularly greater than 30 m/min, still more particularly greater than 40 m/min.

In a 56th aspect according to anyone of the preceding aspects, the drying station (6) is configured for generating and emitting a drying gas at a temperature lower than 100°C, particularly comprised between 60 and 100°C. In a 57th aspect according to anyone of the preceding aspects, the plant (1) comprises at least one station (31) for preparing the sheet fibrous material (T) , optionally placed at the operative section (5) and configured for applying at least on a second side (T2) of the sheet fibrous material (T), opposite to the first side (Tl), a treatment liquid or a treatment foam.

In a 58th aspect according to the preceding aspect, the preparing station (31) is configured for applying, particularly continuously, the treatment liquid or a treatment foam on all the width of the sheet fibrous material (T ) .

In a 59th aspect according to the aspect 59 or 60, the preparing station (31) is configured for laying a treatment liquid or a treatment foam continuous layer on the second side (T2) of the sheet fibrous material (T) , particularly on the fibrous material fixed on the conveyor belt (2) .

In a 60th aspect according to anyone of the preceding aspects from 57 to 59 the preparing station (31) comprises a applicator (36) configured to place at least on the second side (T2) of the fibrous sheet material (T) a treatment liquid or treatment foam.

In un 61st aspect according to the preceding aspect the applicator (36) of the preparing station (31) comprises at least one selected in the group of:

- a spreading blade (37) placed transversally to the conveyor belt motion and spaced above the fibrous sheet material,

a spray dispenser (38) spaced above the fibrous sheet material,

an applicator roll (39) with an associated respective blade for regulating a thickness of the treatment liquid or foam deposited on a lateral surface of the applicator roll, this latter being placed with the rotation axis transversal to the conveyor belt (2) motion and with a lateral surface spaced above fibrous sheet material,

a drum (40) placed with the rotation axis transversal to the conveyor belt motion and with a lateral surface spaced above the fibrous sheet material, the drum (40) exhibiting a hollow interior destined to receive a predetermined quantity of treatment liquid or foam and being provided with a predetermined number of nozzles or slits for dispensing the treatment liquid or foam,

- a distributor (41) comprising a tank (42) configured for receiving the treatment liquid or foam, the tank (42) exhibiting at least one dispensing nozzle (43) defining an outlet of the tank (42), the nozzle (43) extending transversally to the conveyor belt (2) motion all along the width of this latter, the distributor (41) comprising one or more pushers, for example one or more toothed wheels, placed inside the tank and configured for eject the treatment liquid or foam through the nozzle ( 3 ) .

In a 62nd aspect according to anyone of the preceding aspects form 57 to 58, the control unit (34) is active on the preparing station (31) and on the conveyor belt (2), said control unit (34) being configured for:

- receiving a desired value of at least one operative parameter representative of a quantity of the treatment liquid or treatment foam applied on the fibrous sheet material by said preparing station (31), said at least one operative parameter comprising at least one of the following :

o a weight percentage variation per square meter of the fibrous sheet material between a section immediately upstream of the preparing station, wherein the fibrous material has not received the treatment liquid or treatment foam, and a section immediately downstream the preparing station (31), wherein the fibrous material has received the treatment liquid or treatment foam,

o a volume rate of the treatment liquid or treatment foam exiting said preparing station, o a mass rate of the treatment liquid or treatment foam exiting said preparing station,

commanding the preparing station (31) in order to manage the application of the treatment liquid or treatment foam on the fibrous sheet material (T), as a function of the desired value of the operative parameter and the movement imparted to said conveyor belt (2) .

In un 63rd aspect according to the preceding aspect the plant (1) comprises a sensor able to emit a signal relating to the motion of the conveyor belt (2), said control unit (34) being configured for:

- receiving from said sensor, a signal relative to the conveyor belt (2) motion,

- determining as a function of said signal a movement speed of the fibrous sheet material (T) along the advancement direction (A) ,

- as a function of the fibrous sheet material (T) movement speed, commanding the dispensing of the treatment foam dispensed by the preparing station (31) to meet the desired value of said at least one operative parameter, optionally so that the desired values of at least one of the following operative parameters are met: o the foam exhibits, immediately downstream the preparing station (31), a thickness less than 2 mm, o the weight percentage variation per square meter of the fibrous material, between a section immediately upstream the preparing station (31), wherein the fibrous material has not received the treatment foam, and a section immediately downstream the preparing station (31), wherein the fibrous material has received the treatment foam, is comprised between 10% and 50%.

In a 64th aspect according to anyone of the preceding aspect from 57 to 63 the treatment foam dispensed by the preparing station (31) comprises:

- at least one treatment liquid in a quantity comprised between 5% in weight and 75% in weight with respect to the total weight of the foam, said treatment liquid comprising :

- at least one foaming agent in a weight percentage comprised between 0.2% and 5%, preferably between 0.4% and 2%, with respect to the total foam weight,

- water in a quantity needed to reach 100%.

In a 65th aspect according to anyone of the preceding aspects from 57 to 64 the treatment foam is characterized by at least one of the following parameters :

-density of between 0.005 and 0.3 g/cm ³ ,

-average diameter of the cells between 0,05 and 0,5 mm, -average living time of between about 1 and 60 seconds, -expansion ratio between 2:1 and 6:1. In a 66th aspect according to anyone of the preceding aspects from 57 to 65 the preparing station (31) comprises an applicator (36) configured for applying on the second side (T2) of the fibrous sheet material (T) a quantity of treatment foam having, immediately downstream of the applicator, a thickness less than 2mm, particularly less than 1.5mm.

In a 67th aspect according to anyone of the preceding aspects from 61 to 66 the preparing station (31) comprises a foaming machine (44) configured to generate the treatment foam and supply to the applicator (36) , continuously or at predetermined time intervals, a predetermined quantity of treatment foam.

In un 68th aspect according to anyone of the preceding aspects from 57 to 67 the preparing station is configured to define on the second side (T2) of the fibrous sheet of material at least one of:

- a continuous foam layer suitable to cover at least partially the second side (T2) of the fibrous sheet material (T ) ,

- a plurality of discrete foam regions, such discrete foam regions defined on the second side (T2) of the fibrous sheet material (T) being entirely surrounded by fibrous material not covered with foam.

In a 69th aspect according to anyone of the aspects from 57 to 68 the preparing station (31) is configured to have, on the second side (T2) of the fibrous sheet material (T), a predetermined quantity of treatment foam, said predetermined quantity of treatment foam being selected in such a way that the same fibrous sheet material (T) presents a percentage variation in weight per m ² , between a section immediately upstream of the preparing station (31) in which the material fibrous has not received the foam and a section immediately downstream of the preparing station in which the fibrous material has received said foam, between 10% and 50%. In a 70th aspect according to anyone of the preceding aspects from 57 to 69 the treatment foam supplied by the preparing station (31) comprises at least one treatment liquid in a quantity comprised between 5% and 75% in weight with respect to the total weight of the foam, said treatment liquid comprising:

at least one anti-migration agent, preferably selected among alginates, cellulose derivatives, particularly carboxymethylcellulose, hydroxyethylcellulose, acrylic ( co ) polymers , xanthan gum, Arabic gum and guar gum, and/or

a fixing agent, particularly said fixing agent comprising at least one of:

- at least one pH-control agent, preferably selected among sodium bicarbonate, sodium carbonate, ammonium sulfate, ammonium tartrate and citric acid, and at least one hydrotropic agent, preferably selected between urea and thiourea,

- at least one foaming agent in a weight percentage comprised between 0.2% and 5%, preferably between 0.4% and 2%, with respect to the total foam weight,

- water in a quantity needed to reach 100%.

in a 71st aspect according to anyone of the preceding aspects, the plant (1) comprises at least one separating member (32) placed at a terminal portion of the operative section (5), said separating member (32) being configured for contacting at least one side of the sheet fibrous material (T) and detach this latter material from the exposed surface (S) of the conveyor belt (2) . In a 72nd aspect according to the preceding aspect, the separating member (32) comprises at least one idler roll or drum adapted to contact at least the second side (T2) of the sheet fibrous material (T) .

In a 73rd aspect according to anyone of the preceding aspects, the plant (1) comprises at least one ink- printing station placed downstream the operative section (5) of the conveyor belt (2), said printing station being configured for receiving the sheet material arriving from the operative section (5), and ink- printing at least the second side (T2) of the sheet fibrous material (T) .

In a 74th aspect according to the preceding aspect, the printing station provides a digital ink-printing device. In a 75th aspect, it is provided a process of treating a sheet fibrous material (T) comprising the following steps :

- moving a conveyor belt (2) along a closed path,

- constraining, particularly fixing, at least temporarily, a first side (Tl) of a sheet fibrous material (T) to an exposed surface of an operative section (5) of the conveyor belt (2),

- at least partially drying the sheet fibrous material (T) by blowing a gas on the sheet fibrous material (T) during the passage of this latter along at least a portion of the operative section (5),

- withdrawing the sheet material (T) from the conveyor belt (2) after the drying step.

In a 76th aspect according to the preceding aspect, the drying step is performed by blowing a gas on the sheet fibrous material (T) during the passage of this latter at least along bends defined by the operative section (5) .

In a 77th aspect according to the aspect 75 or 76, wherein the step of moving the conveyor belt (2) provides at least the sub-step of moving the conveyor belt (2) inside a treating chamber (9), between an inlet port (10) and an outlet port (11) so that said operative section (5) extends at least partially inside the chamber ( 9 ) .

In a 78th aspect according to the preceding aspect, the length extension of the operative section (5) inside the treating chamber (9) is greater than the maximum distance between the inlet port (10) and the outlet port (11) of the casing (8) .

In a 79th aspect according to anyone of the preceding process aspects, the step of moving the conveyor belt

(2) provides at least the sub-step of moving the conveyor belt (2) inside a treating chamber (9), between an inlet port (10) and an outlet port (11) so that said operative section (5) extends at least partially inside the chamber (9), optionally the length extension of the operative section (5) inside the treating chamber (9) is greater than the maximum distance between the inlet port

(10) and outlet port (11) of the casing (8) .

In a 80th aspect according to anyone of the process preceding aspects, the step of at least particularly drying the sheet fibrous material (T) is performed by blowing a gas on this latter material during the passage of the conveyor belt along the bends defined by the operative section (5).

In a 81st aspect according to anyone of the aspects from 75 to 80, the constraining, particularly fixing step, provides to uniformly fix the whole surface of the first side (Tl) of the sheet material to the exposed surface of the conveyor belt.

In a 82nd aspect according to anyone of the aspects from 75 to 81, the constraining step, before the contacting step between the conveyor belt (2) and the sheet fibrous material (T), provides at least one step of placing an adhesive material on at least a portion of a first side (Tl) of the sheet material (T) and/or on an exposed surface (S) of the conveyor belt (2) .

In a 83rd aspect according to the preceding aspect, wherein applying the adhesive material is performed, particularly continuously, during the conveyor belt (2) and/or sheet material (T) movement.

In a 84th aspect according to the aspect 82 or 83, the adhesive material is applied on a first side (Tl) of the sheet material and/or on an exposed surface (S) of the conveyor belt (2) all over the width of the sheet fibrous material (T) .

In a 85th aspect according to anyone of the aspects from 82 to 84, the adhesive material is continuously applied on an exposed surface (S) of the conveyor belt (2) in order to define on this latter a continuous adhesive material layer.

In a 86th aspect according to anyone of the aspects from 74 to 85, the step of constraining, particularly fixing, the fibrous material (T) on the conveyor belt (2) comprises :

- apply an adhesive material on at least a portion of an exposed surface (S) of the conveyor belt (2) during the movement of this latter along the closed path,

- contacting, particularly by a pressing member, a first side (Tl) of the sheet fibrous material (T) with the exposed surface (S) supporting the adhesive material, by continuously moving the conveyor belt along the closed path,

- fixing the sheet fibrous material (T) and conveyor belt (2) before the step of blowing and drying the fibrous material (T) .

In a 87th aspect according to anyone of the aspects from 76 to 86, the drying step comprises to blow at least a gas flow inside the bends formed by the conveyor belt (2) supporting the sheet fibrous material (T).

In a 88th aspect according to anyone of the aspects from 77 to 87, wherein the step of drying the sheet fibrous material (T) comprises at least the following steps:

- moving the sheet fibrous material (T) , for at least a portion of the operative section (5), inside the treating chamber (9),

- blowing a gas inside the treating chamber (9) in order to define a flow adapted to hit the sheet fibrous material .

In a 89th aspect according to anyone of the aspects from 75 to 88, wherein the process uses an apparatus according to anyone of the aspects from 1 to 74.

In a 90th aspect according to anyone of the aspects from 75 to 89, the drying step comprises blowing a gas on the sheet fibrous material (T) through a plurality of distribution channels (24) apposed along the operative path (5), said distribution channels continuously blowing the gas in order to progressively dry the fibrous material sliding along the operative section (5) .

In an 91st aspect according to anyone of the aspects from 75 to 90, the motion of the conveyor belt (2) and the fibrous material (T) along the operative section (5) comprises moving the belt (2) between at least one intermediate idler member adapted to define at least one ascending and descending sections (15, 16) of the conveyor belt (2), blowing gas is performed on at least the descending and ascending operative sections of the conveyor belt (2) . In an 92nd aspect according to anyone of the aspects from 75 to 91, the motion of the conveyor belt (2) and fibrous material (T) along the operative section (5) comprises moving the belt (2) between a plurality of intermediate idler members, one or more intermediate idler members of said plurality being placed on at least one first row (Fl), while one or more intermediate idler members of said plurality being placed on at least one second row ( F2 ) , said first and second rows of intermediate idler members being placed, according to an operative condition of the plant, at different heights in order to define on the operative section (5) at least one ascending section (15) and one descending section (16), particularly the first row ( Fl ) being placed at a height greater than the height of the second row ( F2 ) . In an 93rd aspect according to the preceding aspect, wherein on each of said first and second rows (Fl, F2 ) a plurality of intermediate idler members are present, moving the conveyor belt (2) comprises, for at least a portion of the operative section (5), sliding the same belt from an idler member of a row to an idler member of the other row, immediately following an advancement direction (A) of the conveyor belt (2); the motion of the conveyor belt (2), and therefore of the sheet fibrous material (T) , defines a sliding motion along to a bends path.

In an 94th aspect according to the preceding aspect, each bend defines a descending, junction, and ascending sections (16, 33, 15) receiving inside the fibrous material (T) which has been also shaped as a bend, the bends being aligned along an advancement direction (A) of the conveyor belt, drying the fibrous material (T) comprises blowing a gas inside each bend through distribution channels placed directly inside said bends . In an 95th aspect according to anyone of the aspects from 80 to 94, each distribution channel (24) substantially extends all along the height of the bend and all along the width of the sheet fibrous material (T), drying the fibrous material comprises at least the following steps:

- delivering a gas to each distribution channels (24) through an inlet conduit (25) placed laterally to the conveyor belt (2), the gas entering the distribution channel (24), laterally to the conveyor belt (2) and according to a direction transversal, particularly normal, to an advancement direction of the conveyor belt (2) ,

- generating, by means of the distribution channel (24), a plurality of gas flows uniformly distributed all along the sheet fibrous material (T) and along the height extension of the bend, particularly at least some of said flows having a component parallel to an exposed surface of the fibrous material sliding along the bend. In an 96th aspect according to anyone of the aspects from 75 to 95, the drying gas flow has a temperature less than 100°C, particularly comprised between 60 and 100°C.

In an 97th aspect according to anyone of the aspects from 75 to 96, a temperature less than 100°C, particularly comprised between 60 and 100°C is defined inside the treating chamber (9) .

In an 98th aspect according to anyone of the aspects from 75 to 97, moving the conveyor belt (2), and consequently the sheet fibrous material (T), is performed at least partially by pulling the same belt by dragging portions (17) emerging transversally from opposite longitudinal sides of the sheet fibrous material (T ) .

In an 99th aspect according to anyone of the aspects from 75 to 98, motion of the sheet fibrous material is performed along the operative section only by moving the conveyor belt (2), the sheet fibrous material (T) , during the whole movement along the operative section, being directly and only contacted by the exposed surface (S) of the conveyor belt (2) . In an 100th aspect according to anyone of the aspects from 75 to 99, the step of moving the conveyor belt, and therefore the sheet fibrous material, along the operative section is done at a speed of 20 m/min, particularly greater than 30 m/min, still more particularly greater than 40 m/min.

In a 101st aspect according to anyone of the aspects from 75 to 100, the step of moving the conveyor belt (2) is done at a predetermined speed such to subject a same section of the sheet fibrous material (T) to the emission of a drying gas flow for a time comprised between 30 and 240 seconds, particularly between 30 and 120 seconds, still more particularly between 30 and 90 seconds .

In a 102nd aspect according to anyone of the aspects from 75 to 101, the process comprises at least a step of preparing the sheet fibrous material, comprising applying, on a second side (T2) of the sheet fibrous material (T) opposite to the side fixed to the conveyor belt (2), a treatment liquid or a treatment foam.

In a 103rd aspect according to the preceding aspect, the preparation step is done after fixing the sheet material (T) on the conveyor belt (2) and before the drying step. In a 104th aspect according to the aspect 102 or 103, the step of applying the treatment liquid or the treatment foam is continuously done and all over the width of the sheet fibrous material in order to define on this latter substantially a layer coating the whole exposed upper surface of the sheet fibrous material.

In a 105th aspect according to anyone of the aspects from 75 to 104, the process comprises at least one step of separating the sheet fibrous material (T) , at least partially dried and exiting the operative section (5), from the conveyor belt (2) exposed surface, during such step, the first side (Tl) of the sheet material, previously constrained, is detached from the exposed surface (S) of the conveyor belt (2), for example by a pressure roll and/or drum adapted to at least partially wind the second side (T2) of the sheet fibrous material. In a 106th aspect according to anyone of the aspects from 75 to 105, the sheet material (T) at least partially dried exiting the operative section is delivered, particularly directly and continuously, to an ink-printing station.

In a 107th aspect according to the preceding aspect, the sheet material (T) at least partially dried exiting the operative section and detached from the conveyor belt (2) is delivered, particularly directly and continuously, to an ink-printing station.

In a 108th aspect according to the aspect 106 or 107, ink-printing the fibrous ma1 erial is directly done on the second side (T2) treated by the treatment liquid or the treatment foam.

In a 109th aspect, a process according to anyone of the aspects from 75 to 108 using the plant (1) of anyone of the aspects from 1 to 74, is provided .

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments and some aspects of the invention will be described in the following with reference to the attached drawings given only in an indicative and therefore non limiting way, wherein:

- Figure 1 is a lateral schematic view of a plant according to aspects of the present invention;

- Figure 2 is a cross-section, along the line II-II, of the plant in Figure 1;

- Figure 3 is a detailed view of the cross-section in Figure 2;

- Figure 4 is a schematic longitudinal cross-section of a plant according to aspects of the present invention;

- Figure 5 is a detail of Figure 4 regarding an inlet station of the plant according to the present invention;

- Figures 6-8 are detailed views of variants of embodiment of an inlet station of the plant according to the present invention;

- Figures 9-11 are further detailed views of the longitudinal cross-section in Figure 4;

- Figures 12-16 show, according to a lateral schematic view, respective embodiments of an applicator which may be used for supplying adhesive material and/or treatment liquid and/or treatment foam in a plant according to the present invention.

DETAILED DESCRIPTION

Treatment plant

1 generally indicates a plant for treating a fibrous material T having a sheet shape and destined to be printed, for example by a digital printing. The plant 1, object of the invention, is useable for treating a sheet fibrous material, for example consisting of, or comprising a fabric and/or a non-woven fabric, before an ink-printing process on at least one side of said sheet. Generally but in a non limiting way, the plant 1 can be applied to the textile or knitted fabric or non-woven fabric industry for preparing a material to be ink- printed .

As it is visible for example in Figure 4, the plant 1 comprises at least one conveyor belt 2 movable along a closed path, particularly between at least one first and one second terminal idler members 3, 4 along a predetermined advancement direction A. The conveyor belt 2 has a structure having two dimensions: length and width, substantially prevalent with respect to a third dimension, such as the thickness; the length is defined along the belt 2 advancement direction A, while the width is defined normal to said direction A. The conveyor belt 2 is defined by a continuous layer having a substantially constant width and thickness along all the development of the belt 2 itself.

As it is for example specifically visible in Figure 5, the conveyor belt 2 has two main surfaces or sides: an exposed surface S and an inner surface I . The inner surface I is configured for directly contacting the idler members adapted to guide the belt along the operative path 5, while the exposed surface S is configured for receiving the sheet fibrous material T; particularly, the exposed surface S is configured for facing and receiving a first side Tl of the sheet fibrous material T (see Figures 5-8, for example) . In a preferred but non limiting arrangement of the invention, the conveyor belt 2 - at least at a longitudinal continuous band of the exposed surface S destined to receive the sheet fibrous material T - is devoid of through openings crossing the thickness of the belt 2 itself; particularly at least the exposed surface S destined to receive the sheet fibrous material T is completely smooth and devoid of holes (through openings, for example) and advantageously devoid of valleys and projections. Advantageously but in a non limiting way, the conveyor belt 2 comprises at least one continuous layer of a waterproof material, defining the exposed surface S and capable of providing the surface S itself, along a view normal to a belt moving direction, with a continuous and preferably rectilinear outline.

As it is visible in the attached figures, at least a portion of the conveyor belt 2 closed path defines an operative section 5 conveying the sheet fibrous material T; actually, the operative section 5 is defined by the belt 2 portion moving the sheet fibrous material T, in other words by the belt portion 2 directly supporting said fibrous material T. The operative section 5 can be defined by a path portion between the first and second idler members 3, 4 or, as illustrated in Figure 4, by the whole belt 2 portion comprised between said members 3, 4: in this latter described arrangement, the operative section 5 substantially extends from the first idler member 3 to the second idler member 4. However, it is not excluded the possibility the operative section 5 could be defined by at least one belt 2 portion extending from the second idler member 4 in the direction of the first idler member 3.

The conveyor belt 2 can only comprise the first and second idler members 3, 4 and therefore having a substantially rectangular closed path, radiused in correspondence of said members; under such condition, the operative section could be defined by at least one rectilinear portion of the rectangular path: the sheet material T would be conveyed by the belt along a rectilinear section, particularly flat (such arrangement is outlined in Figure 4A) .

In a preferred but non limiting arrangement of the invention, the operative section 5 of the conveyor belt 2 is configured for defining at least one or a plurality of bends (see Figure 4, for example) . Particularly, in this latter described arrangement, the operative section 5 is configured for defining at least one section defining, according to an operative condition of the plant 1 itself, an ups-and-downs trend with respect to the first and/or secondo idler member 3, 4.

In other words, the operative section 5 has at least one ascending section 15 and/or at least one descending section 16 of the conveyor belt 2. Specifically, the plant 1 could comprise, in a non limiting way, at least in correspondence of the operative section 5, one or more intermediate idler members adapted to define one or more ascending sections 15 and/or one or more descending sections 16. The accompanying figures illustrate, in a non limiting way, an arrangement of the plant 1 comprising a plurality of intermediate idler members interposed between the first and second terminal members 3, 4. The plurality of intermediate idler members is active at the conveyor belt 2 operative section 5 : the plurality of intermediate idler members comprise a first group of intermediate idler members aligned along a first row Fl, and a second group of intermediate idler members aligned along a second row F2. The first and second rows of intermediate idler members are placed, under an operative condition of the plant 1, at different heights adapted to define on the operative section 5 a plurality of ascending sections 15 and a plurality of descending sections 16; particularly, the first row Fl is placed at a height greater than the height of the second row F2 (see Figure 4, for example) . Actually, along each of said first and second rows Fl, F2 , a plurality of intermediate idler members are placed. At least a portion of the operative section 5 of the conveyor belt 2, is alternatively guided around an idler member of the first row and around an immediately following idler member of the second row, in order to provide the portion of the operative section 5 with an ups-and-downs trend defining said bends. Advantageously, the intermediate idler members of the first row Fl are equidistant from each other along the advancement direction A of the conveyor belt 2; in the same way, also the intermediate idler members of the second row F2 are equidistant from each other along the advancement direction A of the conveyor belt 2. Optionally, the minimum distance between two adjacent intermediate idler members of the first row Fl is substantially equal to the distance present between two adjacent intermediate idler members of the second row F2. In a preferred but non limiting embodiment of the invention illustrated in the accompanying figures, the idler members of the first row Fl are offset from the idler members of the second row F2 along the advancement direction A of the belt 2 itself; particularly, the distance between the idler members of the first and second rows and the offset between these members enable to define at least one ascending section 15 and/or one descending section 16 of the conveyor belt 2 having a slope, with respect to a vertical plane, comprised between 0 and 30°, particularly between 0 and 15°. In this way, each conveyor belt 2 portion extending between two following intermediate idler members of the first row Fl and an intermediate idler member of the second row F2 , comprises a respective descending section 16, a respective ascending section 15 and a respective lower junction section 33 interposed between and connected to said descending and ascending sections; the descending, junction, and ascending sections 16, 33, 15 of each belt portion 2 delimits a respective bend.

As previously described, the operative section 5 represents the belt 2 portion supporting the sheet fibrous material T; the descending, ascending and junction sections 16, 15, 33 are configured for receiving the sheet fibrous material T by facing it towards the interior of said respective bend ( see the detail in Figure 9, for example) . One or more motors 35 active on one or more idler members of the plant 1, operate the conveyor belt 2 and therefore the sheet material T. More particularly, each idler member, both intermediate and terminal, comprises a first and second guiding portions 18, 19 (Figure 2), for example a crown wheel or gear wheel, active on the conveyor belt 2 and respectively arranged in correspondence of the opposite longitudinal edges of the conveyor belt 2: beside this latter. A dragging device 20, such as chain or belt is active on each of said guiding portions 18, 19 of all the plant 1 idler members: the dragging device 20 extends all along the belt 2 closed path and dynamically connects all the idler members. Actually, activating a crown wheel or gear wheel of an idler member by the motors 35 enables, through the dragging device 20, to move all the idler members and therefore to move the belt 2 along the operative path. The accompanying figures illustrate a non limiting arrangement of the plant 1, having a single motor 35 active on a single intermediate idler member; advantageously, it is possible to activate a plurality of motors on respective idler members .

More specifically, the conveyor belt 2 is configured for having a width greater than the maximum width of the sheet fibrous material T; particularly, the conveyor belt 2 comprises at least one first and/or one second dragging portions 17 configured for transversally emerging from opposite longitudinal sides of the sheet fibrous material T. As hereinbefore described, in an arrangement of the plant 1, this latter comprises at least one dragging device 20 active on at least one of said first and second dragging portions 17 of the conveyor belt 2; particularly, such dragging portions 17 are engaged with the dragging device 20 which, as hereinbefore described, is in turn moved by one or more guiding portions 18, 19. In a variant of embodiment, the dragging device 20 is alternatively active on the inner surface I of the belt 2 itself, opposite to the exposed surface S (this arrangement is not illustrated) . Anyway, the dragging device 20, as all the elements adapted to move the belt 2, is configured for moving the belt 2 itself without contacting the exposed surface S, and therefore the sheet fibrous material T.

As hereinbefore described, the conveyor belt 2 can define at least, at the operative section 5, a plurality of bends; particularly, the bends are defined by the alternative movements through the path formed by the intermediate idler members of the first and second rows . In a preferred arrangement of the invention, each intermediate idler member of the first row Fl (the upper idler member) comprises an idler roll or drum 21 configured for directly contacting the inner surface I of the conveyor belt 2 for guiding it along at least one portion of the operative section 5. The roll or drum of the first row therefore enables to suitably support the conveyor belt 2 when passing from the ascending section 15 to the descending section 16 of the bend. The intermediate idler members of the second row being alternatively devoid of rolls or drums; at the junction section 33, the conveyor belt 2 is dynamically guided only by the dragging device 20, active only on the belt 2 portions 17, and the guide portions 18, 19 beside the belt 2. Actually, at the junction portion 33, the belt 2 is only constrained and moved by the lateral dragging portions 17 : in this way, it is possible to prevent the sheet fibrous material T supported by the belt 2, from contacting the moving elements of this latter.

As it is visible in the attached figures, further the plant 1 comprises an applicator 13 configured for placing, on at least one first side Tl of the sheet material T and/or on the exposed surface S of the conveyor belt 2, an adhesive material M capable of constraining, at least temporarily, the sheet fibrous material T to the conveyor belt 2; particularly, the applicator 13 is configured for laying a continuous layer of adhesive material on the first side Tl of the sheet fibrous material T, and/or on the exposed surface S of the conveyor belt 2. In the embodiment illustrated in the accompanying figures, the applicator 13 is in a non limiting way configured for laying an adhesive material continuous layer only on the exposed surface S of the conveyor belt 2, having a width at least equal to the width of the sheet fibrous material T or equal to the width of a portion to be printed of the sheet material. More specifically, the applicator 13 can comprise at least one selected in the group among the following elements: a spreading blade, a spray dispenser, a roll, a drum, a distributor.

Figures 12-16 show different embodiments of the applicator 13.

In a first example, the applicator 13 comprises a spray dispenser (figure 12) spaced above the conveyor belt. In this configuration the adhesive material comprises, in a non-limiting way, a treatment liquid. The applicator 13 may include only one spray dispenser 38 extending along the whole width of the belt conveyor 2 and having a plurality of nozzles 38a that allow the dispenser 38 to apply the adhesive material (liquid) over the entire width of the belt 2. In one variant embodiment of the first example, the applicator 13 may include a plurality of spray dispensers 38, each of which has one or more dispensing nozzles 38a, configured to allow the application of adhesive material M on the entire width of the belt 2.

In a second example, the applicator 13 comprises a spreading blade 37 (Figure 13) placed transversally to the motion of the conveyor belt 2 and spaced above the belt 2. The spreading blade 37 may be associated with a distributor 37a of the adhesive material M configured to place on the belt 2 a predetermined amount of adhesive material M. The blade 37 is placed immediately downstream of the distributor 37a according to the direction of advancement A of the belt and configured for spreading on the latter the adhesive material M dispensed from the dispenser 37a. A spreading blade may advantageously be used for spreading a material M comprising a treatment foam. Figure 13 shows a preferred, but not limitative, embodiment of the distributor 37a comprising a pressurized tank 37b inside of which the material M is present; the pressurized tank 37b is in fluid communication with a compressor 37c configured to introduce pressurized air in the tank 37b so as to allow dispensing of the adhesive material M. In a preferred configuration, the plant 1 comprises a control unit 34 active on the compressor and 37c configured for:

receiving from a sensor a signal relating to an operating parameter representative of at least one of: an internal pressure in the tank 37b, a level of material M inside the tank,

- determining, as function of said signal, the amount of material being delivered from the tank,

- comparing the value for the amount of material being delivered with an optimal value,

- as function of said comparison, command the compressor to control the amount of material being dispensed from the tank.

In a third example, the applicator 13 comprises a drum 40 placed with its axis of rotation transverse to the motion of the conveyor belt 2 and with the side surface spaced above the belt 2 (figure 16) . The drum 40 has a hollow interior to house a predetermined quantity of adhesive material M and is provided with a predetermined number of nozzles or slits for dispensing of the same. The drum 40 is, in a non-limiting way, advantageously used for the application of an adhesive material M comprising a foam: in this configuration, the drum 40 can be powered by a foaming machine 44 configured to generate a predetermined amount of foam which is then sent into the drum 40 which will provide the delivery and spreading of the foam on the belt 2. In a preferred configuration, the control unit 34 is active on the foaming machine 44 and on the drum 40 and configured for :

- receiving from the sensor engaged to the belt 2, a signal relating to the movement of the conveyor belt 2, controlling, as a function of said signal, a belt speed of the conveyor belt 2 along the advancement direction A,

- as a function of the belt conveyor 2 speed, commanding the foaming machine 44 to supply a predetermined quantity of foam to the drum 40,

- as a function of the belt conveyor speed, controlling the rotation speed of the drum 40 so that the same drum may adequately spread the foam on the belt 2.

In a fourth example, the applicator 13 comprises an applicator roll 39 with a respective associated blade for regulating a thickness of the adhesive material M deposited on a side surface of the applicator roll. Applicator roll and blade extend transversely with respect to the conveyor belt 2 and extend substantially for the entire width of said belt. The applicator roll is placed with its axis of rotation transverse to the motion of the conveyor belt 2 and with side surface spaced above the belt 2.

In a fifth example, the applicator 13 comprises a distributor 41 comprising a tank 42 configured to receive the adhesive material. The tank 42 has at least a dispensing nozzle 43 positioned over and in contact with the belt 2: the nozzle 43 extends transversely to the conveyor belt 2 along the entire width of the latter. Inside the tank 42 is present at least one pusher, for example defined by a toothed wheel, configured to dispense the adhesive material M - for example a liquid or a foam - from the nozzle 43. As it can be seen from Figure 15, the nozzle 43 is advantageously provided with a regulator 43a placed immediately downstream the exit of the adhesive material M, with respect to the advancement direction of the belt 2; the regulator 43a is configured to substantially uniformly spread on the belt 2the foam exiting from the nozzle 43.

As described above, the plant 1 may advantageously comprise a control unit 34; in this configuration, the unit 34 may be active on the pusher of the distributor 41 to regulate the amount of adhesive material M to be delivered on the conveyor belt 2. In detail, the control unit 34 is connected to the pusher and is configured for :

- receiving, from the sensor engaged to the belt 2, a signal relating to the movement of the conveyor belt 2,

- controlling, as a function of said signal, a speed of the conveyor belt 2 along the advancement direction A,

- as a function of the speed of the conveyor belt 2, regulating the pusher (for example in the case of a toothed wheel manage the rotation of the wheel speed) so as to deliver a predetermined quantity of material M on the belt.

The applicator 13 can be placed in any location of the operative path of the conveyor belt 2. For example in Figures 4 and 5, the applicator 13 is interposed between the first and second terminal idler rolls 3, 4 just at the operative section. Under such condition, for applying the adhesive material and for then constraining the sheet fibrous material T on said belt 2, the plant 1 will be configured for providing the conveyor belt 2 with a motion along the operative path and for applying the adhesive material on the exposed surface S; only after a predetermined number of runs of the belt 2 around the closed path - during such runs the exposed surface is glued - the first side Tl of the sheet material T is placed in contact with the exposed surface S for constraining it to the belt 2.

A further arrangement of the plant 1 is alternatively illustrated in Figures 6 and 8, in which the applicator 13 is placed between the first and second idler rolls 3, 4 downstream, particularly immediately downstream, the operative section 5. De facto, in this arrangement, the applicator 13 can place the adhesive material on the exposed surface S which can immediately receive the sheet material for defining the operative section 5 : in comparison with the first described arrangement, the belt 2 is not required to move for one or more runs around the closed path before having the possibility of constraining the sheet material to the belt 2.

More particularly, the plant 1 can have an inlet station 7 comprising a pressure member 4, specifically a pressure roll or drum (see Figures 5-8, for example), configured for receiving the sheet fibrous material T and for thrusting it against the conveyor belt 2 exposed surface S for enabling to at least temporarily fix the conveyor belt 2 to the sheet fibrous material T.

Actually, the pressure roll 14 determines the contact point between the sheet fibrous material T and belt 2 and therefore the starting point of the operative section 5. Figure 5 illustrates a first arrangement of the plant 1 wherein the pressure roll 14 is placed upstream the applicator 13 with respect to the belt advancement direction A, while Figure 8 illustrates a variant of embodiment wherein the pressure roll 14 is placed downstream the applicator 13 still with respect to the belt 2 advancement direction A.

Further, the plant 1 comprises a station 31 for preparing the sheet fibrous material T configured for applying at least on a second side T2 of the sheet fibrous material T, opposite to the first side Tl, a treatment liquid or a treatment foam N. De facto, the preparing station 31 is configured for applying on the side opposite to the one fixed to the belt 2 (first side Tl) a treatment liquid or a treatment foam N. More specifically, the preparing station 31 is configured for applying, particularly continuously, the treatment liquid (or treatment foam N) on all the width of the sheet fibrous material T; optionally, the preparing station 31 is configured for laying a liquid (or treatment foam N) continuous layer on the second side T2 of the sheet fibrous material T. In the embodiments illustrated in the accompanying figures, the preparing station 31 is placed in correspondence of the operative section 5 : providing the treatment liquid or treatment foam N on the second side T2 of the fibrous material T is done when this latter is constrained - particularly suitably fixed - to the conveyor belt 2. Therefore, generally the preparing station 31 is placed downstream, particularly immediately downstream, the pressure member 14 and can be considered as a portion of the inlet station 7. However, it is not excluded the possibility of positioning the preparing station 31 outside the operative section 5, and particularly upstream the pressure roll 14; under such condition, it is actually possible to perform the treatment of the sheet material T before fixing the same to the belt 2 (this condition is not illustrated in the accompanying figures) . Still more particularly, the preparing station 31 can comprise at least one selected in the group of the following elements: a spreading blade, a spray dispenser, a roll, a drum, a distributor.

In particular, the preparing station 31 comprises a applicator 36 which comprises at least one selected in the group of: a spreading blade, a spray dispenser, a roll, a drum, a distributor.

In a first example, the applicator 36 of the preparing station comprises a spray dispenser 38 (figure 12) spaced above the fibrous sheet material. In this configuration, the applicator 36 is advantageously configured to dispense a treatment liquid of treatment foam; it is not excluded, the possibility to use a spray dispenser 38 for dispensing a treatment foam. The applicator 36 may include only one spray dispenser 38 extending along the entire width of the conveyor belt 2 and having a plurality of nozzles 38a that allow the dispenser 38 to apply the treatment liquid or the treatment foam over the entire width of the material fibrous sheet T. In a different embodiment of the first example, the applicator 36 may comprise a plurality of spray dispensers, each of which has one or more dispensing nozzles 38a configured to allow the application of the treatment liquid or foam N over the entire width of the fibrous sheet material T.

In a second example, the applicator 36 of the preparing station 31 comprises a spreading blade 37 (Figure 13) placed transversally to the motion of the conveyor belt 2 and spaced above the fibrous sheet material. The spreading blade 37 may be associated with a distributor 37a configured to supply on a portion of the second side T2 of the fibrous sheet material T a predetermined amount of treatment liquid or foam N. The spreading blade 37 is placed immediately downstream of the distributor 37a according the advancement direction A of the fibrous sheet material T and is configured to spread on the second side T2 of the sheet material T the treatment liquid or foam N dispensed from the dispenser 37a. A spreading blade may be advantageously used for spreading treatment foam. Figure 13 shows a preferred but not limitative embodiment of the distributor 37a comprising a pressurized tank 37b in which the treatment liquid or foam N is present; the pressurized tank 37b is in fluid communication with a compressor 37c configured to introduce pressurized air in the tank 37b so as to allow the dispensing of the treatment liquid or foam N. In a preferred configuration, the plant 1 comprises a control unit 34 activate on the compressor and 37c configured for:

receiving from a sensor a signal relating to an operating parameter representative of at least one of: an internal pressure in the tank 37b, a level of a treatment liquid or foam N inside the tank,

- determining as function of said signal, the amount of treatment liquid or foam N being delivered from the tank,

- comparing the value of the amount of the treatment liquid or foam being delivered with an optimum value,

- based on the outcome of the comparison, commanding the compressor so as to control the amount of treatment liquid or foam N being dispensed from the tank.

In a third example, the applicator 36 of the preparing station 31 comprises a drum 40 placed with its rotation axis transversal to the motion of the conveyor belt 2 and with the side surface spaced above the fibrous sheet material (Figure 16) . The drum 40 has a hollow interior to house a predetermined quantity of treatment liquid or foam N and is provided with a predetermined number of nozzles or slits for dispensing the same. The drum may advantageously be used for applying a treatment foam: in this configuration, the drum 40 may be powered by a foaming machine 44 configured to generate a predetermined amount of foam which is then supplied into the drum 40 which will provide the delivery and spreading of the foam on the fibrous sheet material T. In a preferred configuration, the control unit 34 is active on the foaming machine 44 and on the drum 40 and is configured for:

- receiving, from the sensor engaged to the belt 2, a signal relating to the movement of the conveyor belt 2,

- controlling, as function of said signal, a speed of the conveyor belt 2, and consequently a speed of the fibrous sheet material T along the advancement direction A,

- as a function of the speed of the conveyor belt 2, commanding the foaming machine 44 for sending a predetermined quantity of foam to the drum 40,

- as a function of the speed of the conveyor belt 2, controlling the rotation speed of the drum 40 in such a way that the same may uniformly spread the foam on the fibrous sheet material T.

In a fourth example, the applicator 36 of the preparing station 31 comprises an applicator roll 39 associated with a respective spreading blade for regulating a thickness of the treatment liquid or foam N deposited on a side surface of the applicator roll. Applicator roll and spreading blade extend transversely with respect to the conveyor belt 2 and substantially for the entire width of said belt. The applicator roll is placed with its rotation axis transversal to the motion of the conveyor belt 2 and with side surface spaced above the fibrous sheet material. In a fifth example, the applicator 36 of the preparing station 31 comprises a distributor 41 comprising a tank 42 configured to receive the treatment liquid or foam N. The tank 42 has at least a dispensing nozzle 43 positioned over and in contact with the fibrous sheet material T: the nozzle 43 extends transversely to the conveyor belt 2 along the entire width of the latter. Inside the tank 42 at least one pusher, for example defined by a toothed wheel, is present and configured to eject the treatment liquid or foam N through the nozzle 43. As can be seen from Figure 15, the nozzle 43 is advantageously provided with a regulator 43a located immediately downstream the exit of the treatment liquid or foam N, with respect to the advancement direction A of the fibrous sheet material T; the regulator 43a is configured to substantially uniformly spread the treatment liquid or foam N exiting from the nozzle 43 on the fibrous sheet material T.

As described above, the plat 1 may advantageously comprise a control unit 34; in this configuration, the unit 34 may be active on the pusher of distributor 41 for controlling the amount of treatment liquid or foam N to be dispensed on the conveyor belt 2. In detail, the control unit 34 is connected to the pusher and is configured for: - receiving, from the sensor engaged to the belt 2, a signal relating to the movement of the conveyor belt 2,

- controlling, as function of said signal, a speed of the conveyor belt 2, and consequently a speed of the fibrous sheet material T along the advancement direction A,

as function of the speed of the conveyor belt 2, controlling the pusher (for example in the case of a toothed wheel by controlling the rotation of the wheel speed) so as to deliver a predetermined amount of liquid or treatment foam N on the fibrous sheet material T.

In a preferred but not limitative embodiment of the plant 1, the preparing station 31 comprises an applicator 36 configured to apply on the second side T2 of the fibrous sheet material T a quantity of treatment foam; the applicator 36 is configured to dispense on the fibrous sheet material a quantity of foam having, immediately downstream of the applicator 36, a thickness less than 2 mm, in particular less than 1.5 mm. The applicator 36 may have a configuration as illustrated in Figures 12 to 16 and as described above. These foam applicators are fed by a foaming machine 44 (see for example figure 16) configured to generate the treatment foam and supply it to the applicator 36, either continuously or at predetermined time intervals, prefixed amounts of treatment foam.

In greater detail, the preparing station 31 is configured to dispense, on the second side T2 of the fibrous sheet material T, a quantity of foam selected in such a way that the same fibrous sheet material T present a percentage variation in weight per m ² , between a section immediately upstream of the applicator 36 in which the fibrous material has not received the foam and a section immediately downstream in which the fibrous material has received said foam, between 10% and 50%. Advantageously, the foam applicator 36 of the preparing station 36 is configured to define on the second side T2 of the fibrous sheet material at least one of:

a continuous foam layer adapted to cover at least partially the second side T2 of the fibrous sheet material T,

- a plurality of discrete foam regions, such discrete foam regions defined on the second side T2 of the fibrous sheet material T being entirely surrounded by fibrous material not covered with foam.

As described above, in a configuration of the apparatus 1 the same comprises a control unit 34 active at least on the conveyor belt 2 and on the foam applicator 36 of the preparing station 31. The control unit 34 is configured for: - commanding the movement of the conveyor belt 2,

- receiving a desired value of at least one operating parameter representative of an amount of treatment foam to be applied on the fibrous sheet material, said at least one operating parameter comprising at least one of the following:

• a percentage variation in weight per m ² of the fibrous sheet material between a section immediately upstream of the applicator 36, wherein the fibrous material has not received the foam, and a section immediately downstream of the applicator 36, in which the fibrous material has received the foam,

• a volume flow rate of the treatment foam exiting said applicator 3,

• a mass flow rate of the treatment foam exiting said applicator 36,

• A foam thickness at the section immediately downstream of the applicator 36,

- commanding the foam applicator 36 so as to control the application of the treatment foam on the fibrous sheet material T, as function of the desired value of the operating parameter and the movement imparted to said conveyor belt 2, and thus according to the speed of the fibrous sheet material T along the advancement direction A.

In particular, the plant 1 comprises at least one sensor capable of emitting a signal related to the motion of the conveyor belt 2; the control unit 34 is configured for :

- receiving from the sensor a signal relating to the movement of the conveyor belt 2,

- determining, as function of said signal, a movement speed of the fibrous sheet material T along the advancement direction A,

as function of the movement speed of the fibrous material T, controlling the treatment foam delivery to meet the desired value of said at least one operating parameter, optionally in such a way that the desired values of at least one of the following operating parameters are met :

• the foam present, immediately downstream of the applicator 36, has a thickness less than 2 mm, in particular less than 1.5 mm,

• the percentage variation in weight per m ² of the fibrous sheet material, between a section immediately upstream of the applicator 36, wherein the fibrous material has not received the foam, and a section immediately downstream of the applicator 36, in which the material fibrous received the foam, is between 10% and 50%.

Further, the plant 1 comprises a separating member 32 placed in correspondence of a terminal portion of the operative section 5 (see Figures 4 and 11) and is configured for contacting at least one side of the sheet fibrous material T and for separating this latter material from the exposed surface S of the conveyor belt 2. More particularly, the separating member 32 is an element adapted to define the end of the operative section 5. The member 32 comprises at least one idler roll or drum adapted to contact the second side T2 of the sheet fibrous material T.

As it is visible in the accompanying figures, further the plant 1 comprises at least one drying station 6 placed at at least a portion of the operative section 5 and configured for at least partially drying the sheet fibrous material T passing near the station 6 itself. The drying station 6 comprises one or more generators 12, optionally each consisting of a fan or compressor, configured for generating one or more corresponding gas flows adapted to hit at least a portion of the sheet fibrous material T fixed on the conveyor belt 2. Specifically, the station 6 is configured for generating and emitting gas flows at a temperature less than 100 °C, particularly comprised between 60 and 100°C. Advantageously, the drying station 6 is placed immediately downstream the preparing station 31. In a preferred but non limiting embodiment of the plant 1, the preparing station 31 and applicator 13 are both placed in correspondence of the inlet station 7 : the station 31 and applicator 13 are immediately consecutive along the belt 2 advancement direction A. Therefore, the drying station 6 is placed immediately consecutively to the inlet station 7 and therefore is placed immediately downstream the station 31 and applicator 13 along the belt 2 advancement direction A. The station 6 is configured for enabling to at least partially dry the sheet material T on which the treatment liquid was applied. In a preferred but non limiting arrangement of the invention, the drying station 6 substantially extends for all the operative section 5, particularly from the inlet station 7 to the separating member 32 : under such arrangement the station 6 is adapted to blow a gas (for example air) substantially on all the sheet material T constrained on the belt 2.

As it is visible in Figure 3, the drying station 6 comprises a plurality of gas distribution channels 24 connected to one or more generators 12. Each distribution channel 24 is configured for blowing a gas, particularly continuously, in the direction of the exposed surface S of the conveyor belt 2, for progressively drying the sheet material T sliding on the operative section 5. Each distribution channel 24 can receive the gas flows from one or more generators 12. Advantageously, a plurality of distribution channels 24 uniformly distributed along the operative section 5 are present, each channel 24 is configured for treating and then drying a portion of the sheet material T supported by the belt 2 : advantageously, each generator 12 can supply a plurality of distribution channels 24, particularly a number of channels comprised between 1 and 6, still more particularly between 1 and 4.

As hereinbefore described, the conveyor belt 2 can define, for at least a portion of the operative section 5, a plurality of bends; under such arrangement, the plant 1 provides, advantageously but in a non limiting way, to place the distribution channels 24 in correspondence of said bends. Particularly, the distribution channels 24 are configured for blowing a gas at least at the bends and specifically inside these latter. Advantageously, the drying station 6 comprises - for each of a plurality of bends - at least one respective distribution channel 24 placed inside the bend defined by the conveyor belt 2 : each distribution channel 24 is therefore configured for emitting a gas flow towards the sheet fibrous material T supported by the exposed surface S (Figure 4). More particularly, each distribution channel 24 comprises a first and second emitting walls 27, 28 respectively facing the exposed surface S of the descending section 16 and ascending section 15 of the conveyor belt 2: each emitting wall 27, 28 comprises a plurality of through openings 29 configured for enabling to emit a gas towards the sheet fibrous material T of the bend. Advantageously, the emitting walls extend along all the conveyor belt 2 width and, particularly, substantially along the height of the bends. De facto, the emitting walls 27, 28 extend substantially from the idler members of the first row Fl (upper row) to the idler members of the second row F2 (lower row) . The through openings 29 are distributed on each emitting wall 27, 28 along rows transversal, particularly normal, to the advancement direction A of the conveyor belt 2; optionally, the openings 29 rows are, according to an operative condition of the plant 1, substantially horizontal.

De facto, as it is visible in the cross-section view in Figure 3, the through openings 29 are substantially evenly placed on each emitting wall 27, 28 in order to substantially define a regular array of openings 29: in this way, the air flows exiting the openings 29 of the emitting walls 27, 28 can uniformly dry the sheet material T supported by the ascending wall 15 and descending wall 16 of the belt 2.

Advantageously but in a non limiting way, the distribution channel 24 comprises one or more flaps 30 (Figure 9) configured for directing at least a portion of the gas flow exiting the channel 24 itself and for generating one or more respective gas flows having a component, particularly a main component, parallel to the exposed surface S of the conveyor belt 2. Advantageously, each distribution channel 24 has, on both the emitting walls 27, 28, a series of flaps 30 adapted to contact the air flow exiting from all the openings 29 so that all the flows exiting the channel have a component parallel to the exposed surface S . Such arrangement actually enables to generate, at least for the ascending and descending sections of the belt, air flows having a component parallel to the sheet fibrous material T: the parallel component provides to withdraw the moisture of the fibrous material T and therefore to effectively dry this latter.

More particularly as it is for example visible in Figure 2, the drying station 6 comprises an inlet conduit 25 connected to one or more generators 12 and to the distribution channel/s 24: the inlet conduit 25 is placed laterally to the conveyor belt 2 and extends at least along a main portion of, optionally all, the vertical extension of the distribution channel. The conduit 25 is configured for receiving gas flows from one or more generators, and conveying them (sending a gas flow) to the distribution channel 24. De facto, the conduit 25 is configured for providing a gas flow with a direction transversal, particularly normal, to the advancement direction A of the conveyor belt 2. The gas flow is introduced from the conduit 25 laterally in the channel 24 which, in turn, generates flows directed towards the exposed surface S.

Figure 3 illustrates a preferred arrangement of the inlet conduit 25 extending along all the height of the distribution channels 24 from an inlet mouth 26 adapted to receive the flow from the generator 12, substantially placed in correspondence of the first row Fl of the idler members. Further, the conduit 25 comprises one or more service openings connected - for example directly - to the distribution channel 24 and beside the conveyor belt 2; the service mouth/s is/are configured for delivering the gas to the channel 24.

Advantageously, the conduit 25 has a gas passage section at least partially decreasing from the inlet mouth 26 advancing downwards along a development of the same inlet conduit 25. In this way, since the gas flow enters at the mouth 26 placed on the top of the conduit 25, the downwards decreasing section trend is adapted to enable to emit gas flows from the service openings at the same speed: the gas flow introduced at the top of the channel 24 has a speed substantially equal to the speed of the gas flow introduced in the channel at a bottom portion. De facto, the conduit 25 decreasing trend is configured for countering the load losses generated by the same conduit in order to enable to emit gas flows having all the same speed: the channel 24 receives - along all its vertical extension - gas flows at the same speed. In a preferred but non limiting arrangement of the invention, the distribution channel/s 24 has also a gas passage cross-section at least partially decreasing advancing, from the service openings (the gas flows inlet) along the inlet conduit 25 development, transversally to the conveyor belt 2. De facto, each distribution channel 24 has, along the width development, a passage cross- section having a decreasing trend.

Further, the drying station 6 can comprise, in a non limiting way, a casing 8 defining at least one treating chamber 9 inside which at least a portion of the operative section 5 extends. As it is visible in Figure 1, the casing 8 comprises an inlet port 10 configured for constantly enabling the passage of a section of the conveyor belt 2 entering the treating chamber 9, and an outlet port 11 configured for constantly enabling the passage of a section of the conveyor belt 2 exiting the treating chamber 9. In a preferred but non limiting embodiment of the invention, the casing 8 extends mainly along the operative section 5 from the inlet station 7 to the separating member 32 (Figures 1 and 4) . De facto, the inlet port 10 of the casing 8 is placed immediately downstream, along the advancement direction A of the belt 2, of the preparing station 31, or of the applicator 13. In an arrangement of the plant 1, the portion of the operative section 5 crosses the treating chamber 9 so that the longitudinal extension of the portion of the operative section 5, inside the treating chamber 9, is greater than the maximum distance between the inlet port 10 and outlet port 11 of the casing 8. Figure 4 outlines an arrangement of the plant wherein the bends operative section 5 is completely placed inside and is defined inside the treating chamber 9 (the bends extend along all the operative section 5 inside the treating chamber 9) . In such arrangement, each of said distribution channels 24 is placed inside the casing 8 and is configured for blowing a gas on the operative section 5 inside the treating chamber 9. As it is visible in Figures 4 and 9, the operative section 5 of the conveyor belt 2 crossing the casing 8, longitudinally separates the treating chamber 9 in a first and second half-chambers 22, 23; the first half- chamber 22 extends above the exposed surface S of the belt 2, while the second half-chamber 23 extends below an inner surface I of the conveyor belt 2 opposite to said exposed surface S: the drying station 6 is configured for directing a gas flow inside the first half-chamber 22 (for example through the distribution channels 24 supplied by one or more generators 12) towards the sheet fibrous material T temporarily fixed to the exposed surface S of the conveyor belt 2.

From the dimensional point of view, the operative section 5 of the conveyor belt 2 has a perimetral extension - measured along the advancement direction of the belt itself - greater than 20 m, particularly greater than 30 m, still more particularly greater than 50 m. The operative section 5 placed inside the treating chamber 9 has a perimetral extension - measured along the advancement direction of the belt itself - greater than 15 m, particularly greater than 30 m, still more particularly greater than 50 m. De facto, substantially all the operative section 5 is defined by and contained in the treating chamber 9 inside which a gas is blown for at least partially drying the sheet fibrous material .

In a preferred but non limiting embodiment of the invention, further the plant 1 comprises a control unit 34 (Figure 5) active on the conveyor belt 2, particularly on the motor 35 enabling to move the belt 2, and is configured for commanding the movement of the same. Particularly, the control unit 34 is configured for controlling the motor 35 in order to manage the belt 2 moving speed along the closed path. Further, the control unit 34 is active on the drying station 6 and is configured for commanding the station 6 itself and determining a drying gas emission directed at least in correspondence of said operative section 5 of the conveyor belt 2 : the control unit 34 is configured for managing therefore the air flows hitting the fibrous material .

Therefore, the control unit 34 is configured for controlling the moving speed of said conveyor belt 2 and commanding the drying station 6 so that a same section of the sheet fibrous material T is subjected to said gas emission for a time comprised between 30 and 240 seconds, particularly between 30 and 120 seconds, still more particularly between 30 and 90 seconds. More specifically, the control unit 34 is configured for moving the conveyor belt 2 at a speed greater than 20 m/min, particularly greater than 30 m/min, still more particularly greater than 40 m/min. The control unit 34 can substantially control the drying degree of the sheet fibrous material T by controlling the belt 2 sliding speed and the gas flow generators .

Moreover, the plant 1 can comprise an ink-printing station (non illustrated in the accompanying figures) placed downstream the operative section 5 - particularly downstream the separating roll 32 - of the conveyor belt 2. The printing station is configured for receiving the sheet material T arriving from the operative section 5 and ink-printing at least the second side T2 of the sheet fibrous material T . More particularly, the printing station is configured for only receiving the sheet material T exiting the belt 2 closed path and after applying on this latter, treatment liquids and after drying - at least partially - the same material . The printing station, for example a digital ink-printing station, can therefore be placed immediately downstream the casing - along an advancement direction of the fibrous material - and configured for continuously receiving the material T exiting said casing 8. Alternatively, the plant 1 can provide a station collecting a predetermined amount of the treated and dried fibrous material; the printing station therefore could be configured for receiving, by a load batch, the fibrous material of the collecting station.

Process of treating a fibrous material

In addition, the invention refers to a process of treating a sheet fibrous material T, and particularly a process of treating the sheet fibrous material by means of the above described plant 1, and according to one or more of the accompanying claims . The process comprises moving the conveyor belt 2 along a closed operative path. The belt 2 can be moved between the first and second terminal idler rolls 3, 4; the movement is performed by means or one or more motors 35 directly active on the idler members or directly active on the dragging device 20. The conveyor belt 2 defines the operative section 5 conveying the sheet fibrous material; actually the operative section 5 of the belt 2 is defined by the belt 2 portion moving the sheet fibrous material T, in other words by the belt 2 portion directly supporting said fibrous material T. Specifically, the conveyor belt 2 and consequently the sheet fibrous material T, are moved at least partially by pulling the same belt 2 from the dragging portions 17 transversally emerging from opposite longitudinal sides of the sheet fibrous material T. Alternatively, the dragging device 20 is moved by a plurality of guiding portions 18, 19 placed beside the belt 2. Each guiding portion 18, 19 engages a device 20 which laterally engages the belt 2 in correspondence of the lateral portions 17: activating one or more guiding members 18, 19 enables to move the device 20 and consequently the belt 2. Therefore, it is noted that the sheet fibrous material T, at least along the operative section 5, is moved only by moving the conveyor belt 2 : the sheet fibrous material T, during the movement along all the operative section 5, is directly and only contacted by the exposed surface S of the conveyor belt 2. From the quantitative point of view, the step of moving the conveyor belt 2, and therefore the sheet fibrous material T, along the operative section 5, is done at a speed of 20 m/min, particularly greater than 30 m/min, still more particularly greater than 40 m/min. The belt 2 can be moved along an operative section 5 having at least a rectilinear flat section or having at least one difference in height. Advantageously, the operative section 5 defines, for at least a portion of its extension, a plurality of bends. The belt 2 movement along the operative section 5, follows a serpentine trend, in other words an ups-and-downs movement along the ascending and descending sections 15, 16 of the bends. Particularly, conveying the belt 2 and fibrous material T along the operative section 5 can provide to move the belt 2 between at least one intermediate idler member adapted to define at least one ascending section 15 and one descending section 16 of the conveyor belt 2. More specifically, conveying the belt 2 and fibrous material T along the operative section 5 provides to move the belt 2 between a plurality of intermediate idler members; one or more intermediate idler members of said plurality are placed on at least one first upper row Fl while one or more intermediate idle members of said plurality are placed on at least one second lower row F2 : the first and second rows of intermediate idler members are placed, according to an operative condition, at different heights in order to define, on the operative section 5, at least one ascending section 15 and one descending section 16. Still more particularly, a plurality of intermediate idler members are present on said first and second rows Fl, F2. Moving the conveyor belt 2 provides, for at least a portion of the operative section 5, to slide the same belt from an idler member of a row to an immediately consecutive idler member of the other row along an advancement direction A of the conveyor belt; such motion of the conveyor belt 2, and therefore of the sheet fibrous material T, causes the belt to slide along a bends path (serpentine) . As hereinbefore described, each bend of the belt 2 has a descending, junction and ascending sections 16, 33, 15 in which, the fibrous material T also shaped as a bend is supported: the bends are aligned along an advancement direction A of the conveyor belt 2.

The belt 2 can be moved, along at least a portion of the operative section 5 inside a casing 8 defining a treating chamber 9: the operative section 5 inside the treating chamber 9 separates the casing 8 in a first and second half-chambers 22, 23 respectively representing an upper half-chamber inside which the sheet material T slides, and a lower half-chamber. The step of moving the conveyor belt 2 inside a treating chamber 9 provides to slide the same belt 2 between the inlet port 10 and outlet port 10 so that the operative section 5 extends at least particularly inside the chamber 9; advantageously but in a non limiting way, the longitudinal extension of the operative section 5 inside the treating chamber 9, is greater than the maximum distance between the inlet port 10 and outlet port 11 of the casing 8.

Moreover, the process provides to constrain, particularly fixing, the sheet fibrous material T on the exposed surface S of the conveyor belt 2. Specifically, such step provides fixing at least temporarily the first side Tl of the sheet fibrous material T to the exposed surface S of the operative section 5 of the conveyor belt 2. More particularly, the step of fixing the fibrous material T to the belt 2 provides, before a step of contacting the conveyor belt 2 to the sheet fibrous material T, at least one step of providing an adhesive material on at least a portion of a first side T of the sheet material T and/or on an exposed surface S of the conveyor belt 2. The application of the adhesive material can be done, particularly continuously, during the conveyor belt 2 and/or sheet material T movement: the adhesive material is applied on a first side Tl of the sheet material and/or on an exposed surface S of the conveyor belt 2 along all the width of the sheet fibrous material T. The accompanying figures schematically show a plant 1 wherein the adhesive material is applied by means of an applicator 13 only on the belt 2 exposed surface S; the step of applying the adhesive material defines, on the exposed surface S, an adhesive material continuous layer adapted to stably constrain the fibrous material T, along its width, to the conveyor belt 2.

Still more particularly, the step of fixing the fibrous material T on the conveyor belt provides the application of an adhesive material on at least a portion of an exposed surface S of the conveyor belt 2 during the movement of this latter along the closed path; afterwards, the process provides to contact, particularly by means of the pressure member 14, the first side Tl of the sheet fibrous material T with the exposed surface S supporting the adhesive material by always continuously moving the conveyor belt 2 along the closed path: in this way, it is possible to fix the sheet fibrous material T to the conveyor belt 2. The adhesive is continuously applied to the belt 2 which is at the same time moved along the advancement direction A; the sheet material is placed in contact with the belt 2 only when the glued belt portion reaches the pressure member 14. In an embodiment variant of the process, the step of applying the adhesive material is continuously done for a predetermined number of runs of the belt 2 around the closed path, for example for a number of runs comprised between 1 and 10. The step of contacting the fibrous material with the glued belt is performed only after the step of applying the material for a predetermined number of runs around the closed path.

After the step of fixing the fibrous material T to the belt 2 in order to define the operative section 5, the process provides at least a step of preparing the sheet fibrous material T comprising the application on a second side T2 of the material T itself opposite to the side fixed to the conveyor belt 2, of a treatment liquid or treatment foam. The treatment liquid or treatment foam is continuously applied along all the width of the sheet fibrous material T in order to define on this latter substantially a layer covering the whole exposed upper surface S of the sheet fibrous material. This latter step is performed by a preparing station 31, for example comprising at least one applicator roll or drum, at least one liquid spraying device or at least one blade or a distributor. The preparing station 31 is placed in correspondence of the operative section 5 downstream the pressure member 14.

After preparing the sheet fibrous material, the process provides at least one step of drying the same by blowing a gas during the passage of this latter along at least a portion of the operative section 5. As hereinbefore described, the belt 2 can be advantageously configured with bends; under such condition, the process provides to blow at least a gas flow inside the bends supporting the sheet fibrous material T . Blowing the gas on the sheet fibrous material T can be done by means of the plurality of distribution channels 24 aligned inside the bends along the operative section 5. The distribution channels 24 continuously emit a gas in order to progressively dry the fibrous material sliding along the operative section 5. More particularly, blowing the gas is done on at least the ascending and descending sections 15, 16 of the operative section 5 of the conveyor belt 2. As hereinbefore described, each distribution channels 24 substantially extends along all the height of a bend and along the width of the sheet fibrous material T. Drying the fibrous material provides at least a step of delivering the gas to each distribution channel 24 through the inlet conduits 25 placed beside the conveyor belt 2; the gas is supplied laterally into the distribution channel 24 with respect to the conveyor belt 2, and along a transversal direction, particularly normal, to an advancement direction of the conveyor belt 2. Each channel 24 generates a plurality of gas flows evenly distributed along all the width of the sheet fibrous material T and along the vertical extension of the bend; particularly, at least a portion of said flows has a component parallel to an exposed surface of the fibrous material sliding along the bend. From a quantitative point of view, the drying gas blown on the fibrous material T placed on the operative section 5, has a temperature less than 100°C, particularly comprised between 60 and 100°C. The step of drying the sheet fibrous material T can comprise moving at least a portion of the belt 2 inside a casing 8, between an inlet port 10 and an outlet port 11, defining a treating chamber 9. At least a fraction of the gas drying flows can be blown inside the treating chamber 9 so that the same can hit the sheet fibrous material sliding inside said chamber 9. Advantageously, the bends shaped operative section 5 is defined inside the treating chamber 9. The drying step provides therefore to blow air - for example through the distribution channels 24 - inside the chamber 9 and inside the bends. A temperature less than 100°C, particularly comprised between 60 and 100°C, is defined inside the treating chamber 9 of the casing 8. Anyway, the step of moving the conveyor belt 2 is coordinated with the drying step so that the sheet material T is subjected, for a predetermined period of time, to the drying action. Particularly, the belt 2 is moved at a predetermined speed in order to subject a same section of the sheet fibrous material T to a gas flow drying emission for a time comprised between 30 and 240 seconds, particularly between 30 and 120 seconds, still more particularly between 30 and 90 seconds.

Further, the process provides, following the drying step, at least a step of separating the at least partially dried sheet fibrous material T exiting the operative section 5, from the conveyor belt 2 exposed surface; by such step, the first side Tl of the sheet material, previously fixed, is separated from the conveyor belt 2 exposed surface S, for example by a pressure roll and/or drum adapted to at least partially wind the second side T2 of the sheet fibrous material. Moreover, the process can provide a step of delivering the sheet material T, separated from the belt 2, previously treated and partially dried, to at least an ink-printing station for printing the material T. the printing step provides the application of ink at least on the second side T2 on which the treatment liquid was applied, after being dried. The printing station can for example provide a digital ink printer which can receive, continuously or by a load batch, only the sheet material T exiting from the operative section and therefore treated and dried.