TECHNICAL FIELD OF THE INVENTION

The present invention regards a machine for the decoration of three-dimensional articles.

More particularly, the present invention regards a machine for the decoration of three-dimensional articles such as plates, bowls, trays, and the like.

BACKGROUND ART

In the field of decoration of three-dimensional articles such as plates, bowls, trays and the like, machines are known which use inkjet technology.

This technology, which in the field of decoration of ceramic articles has supported or even supplanted other conventional technologies, allows obtaining excellent results with regard to the quality and repeatability of the decorations.

The machines of currently used type comprise a base, which is associated with a support area of the article to be decorated, and a decoration group provided with at least one inkjet print head.

The aforesaid print head comprises respective nozzles suitable to deposit, on the surface of the article, pre-established quantities of the printing fluid (e.g. an ink, an enamel, or other fluid types).

The decoration group comprises means which allow spatially orienting the respective printing head in order to follow the curvature of the article to be decorated, so as to be able to achieve the desired decorations even on non-flat surfaces, tilted surfaces, and the like.

In some versions of the machine, the decoration group comprises multiple print heads or groups of print heads, separated from each other mainly based on the type of printing fluid delivered.

This means that the single print heads or groups of print heads can be actuated and controlled in an independent manner, in relation to the specific decoration work to be carried out with a specific fluid.

Due to this, it is possible to autonomously control the supply of different fluids, for example inks of different color.

The latter expedient certainly allows obtaining the maximum versatility of the machine in making many different types of decorations, which as stated are marked by very high levels of quality and repeatability.

Nevertheless, the machines of the above-described type are able to carry out a specific decoration work on only one article at a time, on which the different print heads or the different groups of print heads, provided in the machine itself, operate in succession.

In other words, the production rate of the machine is conditioned by the time interval necessary for carrying out the complete decoration of a single plate.

This can constitute a considerable limit in specific situations in which a higher production rate is instead requested, to be obtained nevertheless with the same quality level of the decoration work carried out.

OBJECTS OF THE INVENTION

The aim of the present invention is to improve the state of the art.

Within such aim, an object of the present invention is to make a machine for the decoration of three-dimensional articles which allows obtaining a reduction of the production operative times with respect to those attainable with the known machines that are currently diffused on the market, at least with the same quality level of the obtainable results.

Another object of the present invention is to implement a machine for the decoration of three-dimensional articles which allows simultaneously processing a certain number of articles.

A further object of the present invention is to provide a machine for the decoration of three-dimensional articles that is structurally simple and inexpensive.

Still another object of the present invention is to make a machine for the decoration of three-dimensional articles that is more flexible and versatile than the known machines.

This aim and these objects are achieved by the machine for the decoration of three- dimensional articles according to the enclosed claim 1 . The machine according to the invention comprises a base, support means for a plurality of articles to be decorated, associated with the base, and a decoration group for decorating the articles, associated with said base, and comprising a plurality of print heads.

According to one aspect of the invention the support means comprise at least one carousel rotatable around a first rotation axis, and provided with a plurality of support areas for respective articles to be decorated; in addition, the carousel is associated with first rotatable actuation means for selectively positioning each support area at a respective print head.

Each print head is of the inkjet type, comprising at least one respective head with nozzles that deliver a specific printing fluid.

Each of the support areas comprises respective second rotatable actuation means, suitable for rotating the respective article around a respective second rotation axis parallel to the aforesaid first rotation axis.

The decoration group of the machine comprises means for translating each of the print heads along respective translation directions perpendicular to the aforesaid first rotation axis: in addition, each print head comprises respective means for varying the tilt of the print head.

In addition, each of the print heads comprises means for varying the tilt of the respective head for the correct positioning of the ejector nozzles with respect to the surface to be decorated of the respective article.

According to one aspect of the invention, the means for varying the tilt comprise a rotary actuator and a mechanism adapted to transform the motion of the output shaft of the rotary actuator into a rotation motion of the print head around a respective pivoting axis.

The dependent claims refer to preferred and advantageous embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention will be better understood by each man skilled in the art from the following description and from the enclosed drawing tables, given as a non-limiting example, in which:

figure 1 is an axonometric view of the machine according to the invention;

figure 2 is a detailed perspective view of the decoration group of the machine; figure 3 is a detailed perspective view of one of the print heads of the machine.

EMBODIMENTS OF THE INVENTION

With reference to the enclosed figure 1 , reference number 1 overall indicates a machine for the decoration of three-dimensional articles according to the present invention.

The machine is suitable for specifically decorating the surface of three-dimensional articles such as plates, bowls, trays and the like, of any shape and size, made of any material.

For example, the articles can be made of ceramic material.

Nevertheless, it is underlined that the machine could also be employed for the surface decoration of other types of three-dimensional articles, such as bottles, cups, containers, or anything else, without particular limitations.

In addition, the machine 1 can, indiscriminately, operate autonomously or be inserted in a more complex line for the decoration of articles, in which it can constitute one of the various production stations.

In figures 1-3, the article 2 to be decorated is constituted, only by way of example, by a plate.

As stated, however, the article 2 could be of any other type, for example it could be a bowl, a tray, or even a cup, a bottle, more generally any article with three- dimensional shape whose surface must be decorated according to a specific pattern. It is observed that the machine 1 could also operate on non-three-dimensional articles 2, i.e. flat or two-dimensional articles such as sheets, tiles and the like.

Nevertheless, the application of greater - though not exclusive - practical interest is that of the decoration of three-dimensional articles 2.

The machine 1 comprises a base, indicated overall with 3.

The machine 1 also comprises support means 4 for a plurality of articles 2 to be decorated. The support means 4 are associated with the base 3, in the way described hereinbelow.

The machine 1 comprises a decoration group 5 for decorating the articles 2.

The decoration group 5 is associated with the base 3, in the way described hereinbelow.

The support means 4 are associated, i.e. placed in communication, with means for loading the articles 2 to be decorated, and/or for unloading the articles 2 already decorated.

For example, according to one embodiment of the invention, the support means 4 can be associated with a robot, or robotic arm, which provides for loading the articles 2 to be decorated and for unloading the articles 2 already decorated, by picking them up and/or positioning them from/on respective dedicated transport lines.

The decoration group 5 comprises a plurality of print heads 6.

The print heads 6 are of inkjet type.

It is specified herein that the definition of inkjet, referred to the particular types of print heads 6 used, generally refers to the use of printing fluids of any type, hence not only inks, but also enamels or still other types, without limitation (generally, any fluid suitable for being applied on a surface of an article 2 in order to obtain a decorative effect, or the like).

Each print head 6 comprises at least one respective head 7, with relative ejector nozzles for the printing fluid.

In one embodiment of the machine, each printing head 6 can be associated with a single printing fluid, for example an ink of a single color; nevertheless, in other embodiments, each printing head 6 could be associated with more than one printing fluid, i.e. with inks of multiple colors, for example by mounting multiple heads 7 on the same printing head 6.

In general, each head 7 is of the type suitable to deliver a controlled quantity, controlled over the unit of time, of micro-drops of a printing fluid - e.g. ink - intended to be deposited on the surface of the article 2 to be decorated. Of course, the type of head 7 can be varied in relation to the specific application to be achieved.

For example, heads 7 already available on the market as commercial components can be used, hence they must only be mounted on the print heads 6.

According to one aspect of the invention, the support means 4 comprise at least one carousel 8.

The carousel 8 is rotatable around a first rotation axis A.

The carousel 8 comprises a plurality of support areas 9 for respective articles 2 to be decorated.

The support areas 9 are arranged along an ideal circumference which follows the peripheral portion 8a of the carousel 8.

According to another aspect of the invention, the carousel 8 is associated with respective first rotatable actuation means 8b.

As will be clearer hereinbelow, the first rotatable actuation means 8b are suitable to selectively position each support area 9 for the articles at a respective print head 6 provided in the decoration group 5.

The first rotatable actuation means 8b comprise, for example, an electric gear motor group supported in the base 3, or any other kind of rotary actuator suitable for the application.

In the present embodiment of the invention, the first rotation axis A is vertically oriented.

In other embodiments, the first rotation axis A could be oriented in a different manner.

The decoration group 5 comprises a support slab 10 for supporting the printing heads 6.

The slab 10 is substantially disc-shaped; the slab 10 therefore has an axis of cylindrical symmetry which coincides with the first rotation axis A.

The slab 10 is supported above the carousel 8, coaxial with the latter.

In particular, the slab 10 is supported at the top of a tower 10a, coaxial with the first rotation axis A. The tower 10a projects upward from the base 3 and it passes through a central hole 10b of the carousel 8.

According to another aspect of the invention, and with reference to figure 2, the decoration group 5 comprises translation means 1 1 for each of the print heads 6. In particular, the translation means 1 1 are adapted to translate each of the printing heads 6 along respective translation directions B perpendicular to the aforesaid first rotation axis A.

More in detail, each translation direction B is radially oriented with respect to the first rotation axis A: consequently, each print head 6 can be brought close to or moved away from the first rotation axis A, in relation to the specific operative needs.

The translation means 1 1 comprise, for each of the print heads 6, a screw actuator 12 supported by the upper face of the slab 10.

The screw actuator 12 is coupled to a respective nut screw 13, integral with the print head 6.

The print head 6 comprises, for such purpose, a support carriage 14 which is integral with the aforesaid nut screw 13.

The support carriage 14 is slidably associated with the upper face of the slab 10: for example, between the support carriage 14 and the upper face of the slab 10, linear guide means can be provided, of any type suitable for this specific application.

Due to the translation means 1 1 , the head 7 of each print head 6 can be radially moved with respect to the slab 10 in order to reach different portions of the surface of the article 2 being processed.

According to another aspect of the invention, the support areas 9 of the carousel 8 are mutually angularly equidistant around the first rotation axis A.

In addition, the machine 1 comprises at least one loading/unloading station 15 for loading/unloading articles 2 to be decorated or articles 2 that are already decorated.

In the embodiment of the machine 1 represented in the figures - and only by way of example - the carousel 8 comprises seven support areas 9.

At any operating instant of the machine 1 , one of the support areas 9 is situated at the loading/unloading station 15.

At this loading/unloading station 15, decoration processing is not carried out, but rather only the operations of positioning the articles 2 to be decorated and picking up those already decorated are carried out.

In the carousel 8, any number of support areas 9 can evidently be provided, in relation to the specific application needs; in addition, if necessary, in the machine 1 a different number of loading/unloading stations 15 can be provided.

According to a further aspect of the invention, each of the support areas 9 comprises respective second rotatable actuation means 16.

The second rotatable actuation means 16 are suitable for rotating the respective article 2 around a respective second axis C.

Each second rotation axis C is parallel to the first rotation axis A, as shown in particular in figure 1.

The second rotatable actuation means 16 comprise, for example, an electric gear motor group integral with the carousel 8, or any other rotary actuator, also of another type, suitable for this specific application.

The carousel 8 thus comprises, at each of the support areas 9, a respective recess 9a for housing the second rotatable actuation means 16.

According to another aspect of the invention, each of the print heads 6 comprises means for varying the tilt 17 of the respective head 7.

The means for varying the tilt 17 allow obtaining, during use, the correct positioning of the ejector nozzles of the head 7 with respect to the surface of the article 2.

As can be understood, this is particularly important and advantageous if the article 2 does not have flat geometry, but rather has at least one surface portion to be decorated which is three-dimensional.

More in detail, and with particular reference to figure 3, the aforesaid means for varying the tilt 17 comprise, for each of the printing heads 6, a rotary actuator 18. The rotary actuator 18 is integral with the support carriage 14 of the print head 6. The rotary actuator 18 can include at least one speed reduction stage 18a. The means for varying the tilt 17 comprise a mechanism suitable to transform the motion of the output shaft 18b of the rotary actuator 18 into a rotation motion of the head 7 (i.e. of the support 22) around the pivoting axis 22a.

More particularly, such mechanism can comprise (or be constituted by) a crank mechanism 19, which connects the rotary actuator 18 to the head 7.

More in detail, the crank mechanism 19 comprises a first member 20 pivoted to the output shaft 18b of the rotary actuator, and a second member 21 pivoted both to the first member 20 and to the head 7.

For such purpose, the head 7 is associated with a respective support 22, which is pivoted to the aforesaid second member 21 of the crank mechanism 19.

The support 22 is pivoted to the slab 10 of the decoration group 5 at a pivoting axis 22a perpendicular to the first rotation axis A: more in detail, the first pivoting axis 22a is arranged with tangential orientation with respect to the slab 10.

The pivoting axis 22a is parallel to the axis around which the second member 21 and the support 22 are hinged to each other.

As can be easily understood by observing figure 3, a clockwise rotation of the output shaft 18b corresponds with a clockwise rotation of the support 22 around the pivoting axis 22a; in the same manner, an anti-clockwise rotation of the output shaft 18b corresponds with an anti-clockwise rotation of the support 22 around the pivoting axis 22a.

It is thus possible to vary, in a very simple and totally automated manner, the tilt of the plane on which the ejector nozzles of the head 7 lie, with respect to the plane of the slab 10, which is of course parallel to the plane on which all the articles 2 being processed lie.

According to one aspect of the invention, the support means 4 are movable from an inactive position to an operative position, in which the print heads 6 operate on the surface of the respective articles 2.

More in detail, the aforesaid inactive position provides that the support means 4 are lowered and far from the decoration group 5, while in the operative position the support means 4 are raised such that each print head 6 can come close to the surface of the respective article 2.

In order to obtain this result, the support means 4 are provided with respective means for translating along the first rotation axis A.

In another embodiment of the invention, in a functionally equivalent manner, the support means 4 for supporting articles 2 can be maintained fixed with respect to the base 3, while the decoration group 5 can be provided with respective means for translating between an inactive position (raised) and an operative position (lowered).

According to another aspect of the invention, each print head 6 is provided with feeding means 23 of a printing fluid to the respective head 7.

The feeding means 23 are operatively connected to a respective tank of the printing fluid, which can be incorporated on the print head 6, or which can be housed in a remote position, for example in a suitable seat provided in the base 3.

The feeding means 23 can also comprise a respective system for recirculating the printing fluid, which maintains the fluid itself in the optimal conditions for being applied on the surface of the article 2 to be decorated, even in the time intervals in which a specific print head 6 is not operative.

The feeding means 23 of each of the print heads 6 are operatively controlled by a local control unit 24, which controls and manages the delivery of the relative printing fluid to the head 7.

Both the feeding means 23 and the local control unit 24 are integral with the support carriage 14 of the print head 6.

In particular, the feeding means 23 and the local control unit 24 are integral with an extension 14a of the support carriage 14.

The feeding means 23 and/or the local control unit 24 could also be provided elsewhere in the decoration group 5.

The machine 1 according to the invention also comprises a central processing and control unit 25.

The central processing and control unit 25 is operatively connected to all the functional groups and actuators of the machine 1 , including the local control unit 24 and the feeding means 23 for the various print heads 6.

The operation of the various groups of the machine is coordinated in a manner such that the combination of the single decorative designs executed by the various print heads 6 overall attains, on the surface of the article 2, a polychromatic decorative pattern, possibly also complex, and of high quality and repeatability.

The operation of the machine 1 according to the invention is fully intuitive, in light of the above disclosure.

It is assumed that a specific decoration work to be carried out on articles 2 (i.e. a specific decorative pattern to be attained) consists of a certain number of single decoration steps that each print head 6 must execute (for example, the overall work can be constituted by the combination of different decoration steps carried out with print inks of different color).

The support means 4 are initially in the lower inactive position.

In this position, the articles 2 to be decorated can be introduced into the machine 1. An article 2 to be decorated is therefore positioned (manually or, as stated above, with the aid of a robot or another similar automatic device) on the support area 9 that is situated at the loading/unloading station 15.

At the loading/unloading station 15, i.e. on top of the latter, the decoration group 5 does not comprise print heads 6.

The carousel 8 is driven to rotate a pre-established angular excursion such to carry the just-loaded article 2 to below a specific print head 6 (e.g. that which in that moment is situated immediately adjacent to the loading/unloading station 15).

The above-described operation is repeated by loading further articles 2 into the machine 1 , and the carousel 8 is rotated for subsequent steps until all the support areas 9 of the carousel 8 itself are provided with a respective article 2 to be decorated (except that corresponding with the loading/unloading station 15).

At this point, the support means 4 can be raised into the operative position, and each print head 6 can carry out a specific decoration processing on the surface of the respective article 2.

In order to achieve this, during the execution of the decoration the translation means 1 1 and/or the means for varying the tilt 17 of each of the print heads 6 can be selectively actuated, so as to carry, instant-by-instant, the respective head 7 into the correct position on the surface of the article 2 in order to realize a specific pattern.

At the same time, also the second rotatable actuation means 16 can be actuated for each support area 9, which allow rotating the article 2 around its axis of symmetry: in this manner, it is possible to carry any portion of the surface of the article 2 to below the head 7.

When all the print heads 6 (i.e. those actually active) have terminated their step of decoration on the respective article 2, the carousel 8 is driven to rotate a predetermined angular excursion, so as to carry each article 2 present on the machine 1 to another print head 6, where it will undergo a different and subsequent decoration step.

As can be understood, therefore, at any instant of the machine 1 operation, each processing station carries out a specific decoration step on a respective article 2: in other words, at each instant of the operation, six articles 2 are simultaneously decorated - in this particular case.

This clearly allows considerably reducing the production times, since in the time interval in which a machine of known type completely decorates one article 2, the machine 1 according to the present invention allows completely decorating a plurality of articles 2.

When a specific article 2 is moved below each of the print heads 6 - or in other words when it has undergone all the steps necessary for obtaining the final decorative design - it is carried, by the carousel 8, to the loading-unloading station 15, where it is picked up (for example by a robotic arm).

As the already-decorated articles 2 are picked up from the machine 1 , other articles to be decorated can be loaded at the station 15, and the production cycle continues without pause.

The above description assumes that all the print heads 6 present in the decoration group 8 participate in the execution of a specific overall decorative pattern. Of course, there can be production situations in which one or more print heads 6 are inactive (e.g. because the ink of a specific color is not used in executing a decoration): in this case, the print head 6 which is not active is skipped by the rotation of the carousel 8, which carries each article 2 to the immediately successive print head 6.

It is thus seen that the invention attains the proposed objects.

The decorating machine according to the present invention allows simultaneously attaining, on certain three-dimensional articles, decorations that are also polychromatic and complex, with operating times that are decidedly lower than those of the machines of type presently diffused on the market.

The result is obtained with a machine that is structurally simple and inexpensive, easy to assemble, also using numerous already-available commercial components, and also easy and quick to insert in already-existing production lines.

The use of inkjet print heads 7, controlled with precision by the respective local control units 24, allows obtaining infinite graphical solutions and infinite chromatic combinations on the surface of the articles 2, without any adjustment intervention or parts substitution.

Another considerable advantage that the machine 1 according to the present invention allows attaining is the possibility of simultaneously working articles 2 that are not identical to each other.

For example, since each print head 6 can be programmed in order to execute a specific decorative design on an article 2, in a same work cycle the machine 1 can execute separate processing on single articles 2, which in the end will have different appearances from each other.

Hence, since the heads 7 of each print head 6 can be automatically moved with respect to each other, also the shape of the articles 2 being simultaneously processed on the machine 1 can be different: in other words, the machine 1 can simultaneously work articles 2 with different shape in order to attain decorative pattern thereon that are also different.

This means that the machine according to the invention, in addition to having improved performances from the standpoint of operating times, is also considerably more versatile with respect to the devices of known type, since it can effectively carry out the processing of batches of different products, and small amounts thereof.

The present invention has been disclosed according to preferred embodiments, but equivalent variants can be conceived without departing from the scope offered by the following claims.