“APPARATUS FOR THE IN-LINE PRODUCTION AND PRINTING OF CARDBOARD PRODUCTS AND CORRESPONDING METHOD”

FIELD OF THE INVENTION

Embodiments described here concern an apparatus and method for the in-line production and printing of cardboard products, for example but not exclusively corrugated cardboard.

BACKGROUND OF THE INVENTION

For the production of cardboard products, in particular glued and stitched boxes, it is known, for example, to use an apparatus defined as a “casemaker” which, starting from a flat cardboard sheet, makes said products by means of suitable folding and gluing and/or stitching processes. A known plant for the production of boxes is described for example in document US-A-2013/0017940.

Typically, a production line for the production of cardboard products, for example a casemaker, receives the cardboard from a feed section connected to a production station which, with the aid of suitable accompanying rollers, are fed along a production line toward an in-line series of sections or machines that process the cardboard until the box is formed.

In particular, a casemaker comprises an in-line printing section, a slitting and creasing section called a slotter, a transfer for the folding and joining of the base provided with two longitudinal members with a system of rollers and belts, which gradually and simultaneously provide to fold the cardboard, and a well section in which the finished product, that is, the flat boxes, are packed.

The industry of flat and corrugated cardboard today uses different types of inline printing, so as to be able to customize the packaging according to the needs/requests of the client.

Among the various methods and machinery currently in use there are: offset, flexographic, rotogravure and digital printing. Each of these has specific characteristics of performance and corresponding objective limitations.

The adoption of machinery and methods is based on the different types of raw material used, paper or cardboard, the type of semi-finished flat and corrugated cardboard and the expected result downstream of the various processes. Another substantial aspect that must be considered is the expected production performance, that is, production times, print quality and variety.

Offset printing is an indirect printing system because the ink is transferred, from the aluminum plate on which the subject to be printed is engraved, to a rubber cylinder and, finally, to the print substrate (commonly paper or flat cardboard).

This operation, which is rather complex, provides that the ink contained in the inkwell (or tank) first passes inside the grinding unit. The plate, wound on a cylinder, is subsequently touched by the wetting rollers, which deposit a film of water on it, and by the inking rollers, which transfer the ink to it. In turn, the aluminum plate transfers the ink onto a rubber cylinder which will imprint the graphics on the print substrate.

The main advantages of offset printing are certainly the high quality and high printing speed. This type of printing is normally used for rather high production volumes, as the plant costs do not make it economical for small runs.

Flexographic printing, also called flexo printing, is a direct technique that uses rubber cliches that transfer the ink directly onto the substrate to be printed.

The ink passes from a tray to the anilox roller (usually made of steel or ceramic) where a blade (or doctor) removes the excess. The ink then passes to the printing cylinder which deposits it on the substrate to be printed.

Cells or in other words, recesses, are engraved on the anilox roller, and are filled with ink. A higher concentration of cells per square centimeter is ideal for obtaining a more defined result. On the contrary, a lower concentration of cells is useful for printing on large surfaces.

Initially this technique did not give results of particular quality, but the introduction of digital engraving technology (Flexographic CTP) has improved the results. This technique is used to print mainly on plastic films and corrugated cardboard.

Rotogravure printing is a direct and rotary printing. The printing method provides that an inked roller deposits the ink directly on the print substrate. The printing roller is made of metal and is covered with a layer of copper on which the subject to be printed is engraved. The engraved areas are inked from an inkwell and the excesses are eliminated by a doctor, as happens in flexographic printing. At this point, the engraved roller transfers the ink onto the paper by pressing on it.

The printing roller has a series of cells of different depths: the deeper the cells, the more ink they can contain and the darker the print will be, because more ink will be deposited on the paper. Usually this technique is used for very high production volumes, of millions of copies.

Digital printing is a technique that uses a digital process thanks to which the ink is imprinted directly (or indirectly) on the print substrate, without the use of matrices or cliches. This category includes different printing techniques, such as for example inkjet, xerographic, toner, etc.

In most digital processes the ink is not absorbed by the print substrate but forms a layer on it which is fixed, for example, through a thermal process in the case of toner, or thanks to a polymerization process in the case of UV inkjet ink.

One disadvantage of known printing technologies, with the exception of digital printing, is the common limitation of printing in series without being able to customize the individual box or package, during the production process. On the other hand, digital printing is characterized by the possibility of being able to customize every single component of the production but it can be used for very small formats of boxes and packaging and, because of the high costs due to low productivity, it is uneconomical to use it for high productions.

It is also known to use laser marking to customize products for packaging.

To date, however, it is not used in the corrugated cardboard and paper transformation industries for reasons of printing speed, and laser marking is the responsibility of the user of the packaging who, when a product is packaged, has to customize it.

A known laser marking system used on plastic materials, for example polyethylene, is described in document CN-U-209063619.

Inkjet marking is a technology used on the production lines of the user of the packaging, automatic packaging machines, extrusion plants, filling machines and others. It boasts a good operational flexibility that is difficult to achieve by other technologies since it can generally rely on a wide range of inks. The limitations of this technology are:

- the printing position: the inkjet must be located either laterally with respect to the packaging or in a position where the inkjet goes from the top downward, - the printing speed: the printing speed with the inkjet is significantly lower than the times that the machinery used in the cardboard and paper transformation industry has.

There is therefore a need to perfect a printing apparatus and method which can overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to provide an apparatus and a method for printing on cardboard in a line for the production of packages or products in flat and corrugated cardboard.

Another purpose of the present invention is to provide a versatile apparatus and method which allow to customize and modify the type of printing without stopping the machine.

Another purpose is to provide an apparatus and a method which allow to print on cardboard in a high productivity line without negatively affecting the production.

Another purpose is to provide a printing apparatus of reduced constructive complexity which can easily be integrated on a production line.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes, an apparatus for the in-line production and printing of cardboard products is provided, which comprises: one or more cardboard substrates on which at least one layer of photosensitive paint is deposited; a station for shaping the substrates configured to manufacture the products, downstream of which there is directly coupled in-line a laser printing station.

The laser printing station comprises a movement member, configured to move the products in a direction of advance in coordination with the productivity of the shaping station, and at least one laser printing device located along the movement member and configured to emit a laser beam, by means of which to imprint a printed code on the layer of photosensitive paint present on the products, in transit in the direction of advance thanks to the movement member.

The apparatus can comprise at least one feeding station configured to feed the shaping station with the substrates in a flat configuration, in particular cardboard sheets, preferably pre-cut, to be worked in order to obtain the products in the form of cardboard boxes.

The apparatus can comprise at least one station, located upstream or downstream of the feeding station, configured to deposit the layer of photosensitive paint on one or more areas of the surface of the substrates.

The photosensitive paint comprises pigments which, once they come into contact with the laser beam, generate a print. However, known photosensitive paints do not have the characteristics required to be used in an apparatus for the production of corrugated cardboard without negatively impacting productivity.

Applicant, therefore, has identified a formulation suitable for the field of application, in particular obtaining a photosensitive paint with advantageous characteristics of viscosity, drying times, etc.

Applicant has also identified the type of laser printing device to be combined with this specific formulation so as to cooperate with such formulation in order to obtain the desired prints.

The laser printing station is versatile, since it can be substantially positioned at any point whatsoever along the production line of the apparatus in which the corrugated cardboard product is moved.

The laser printing station allows to print a printed code, even different on each occasion, during the advance of the products without compromising the production performances of the apparatus.

In some embodiments, the manufacturing station is configured to form boxes and comprises a folding assembly associated with the movement member and configured to receive and fold cardboard sheets, in one or more points along a folding axis parallel to the direction of advance, in order to form the boxes.

In accordance with some embodiments, the shaping station is a folding station or machine.

The gradual folding occurs while the product advances along the movement member in order to obtain a folded product with two substantially overlapping faces.

In some embodiments, the laser printing station can advantageously operate in substantial correspondence with the point on the movement member in which the folded product transits.

In accordance with some embodiments, the laser printing station can be configured to print one or more surfaces of the folded product corresponding to one or more walls of the box when it is formed.

The invention also concerns a method for the in-line production and printing of cardboard products, which provides to carry out, directly downstream of the shaping of corrugated cardboard substrates provided with at least one layer of photosensitive paint in order to obtain the products, a laser printing of the products that advance in the direction of advance in coordination with the productivity of the shaping of the products, by emitting a laser beam which imprints a printed code on a respective layer of photosensitive paint present on a corresponding product in transit in the direction of advance.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of some embodiments, given as a non-restr ictive example with reference to the attached drawings wherein:

- fig. 1 is a top view of a schematic and partial representation of an apparatus for the in-line production and printing of corrugated cardboard products in accordance with possible embodiments described here;

- fig. 2 is a lateral view of fig. 1.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be combined or incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

We will now refer in detail to the possible embodiments of the invention, of which one or more examples are shown in the attached drawings, by way of a non-limiting illustration. The phraseology and terminology used here is also for the purposes of providing non-limiting examples.

With reference to figs. 1 and 2, the invention concerns an apparatus 100 for the in-line production and printing of corrugated cardboard products 12 comprising a shaping station 102 “folding zone” of the products 12 downstream of which there is directly coupled in-line a laser printing station 10.

The apparatus 100 also comprises one or more corrugated cardboard substrates 17, for example sheets or suchlike, on which at least one layer of photosensitive paint is deposited. The products 12 are obtained as a result of the folding of the substrates 17 in the shaping station 102, for example in the form of cardboard boxes. These products 12 will therefore be provided with at least one layer of photosensitive paint.

However, we do not exclude embodiments in which the station 10 is coupled in positions other than those described here, which are to be considered as nonlimiting examples.

In other embodiments, the station 10 described here can also be used in other known apparatuses of the cardboard industry, preferably configured for the production of other products comprising corrugated cardboard not limited to boxes, for example sectioned planar sheets, planar sheets stacked in a zig-zag pattern, etc.

The apparatus 100 can comprise a feeding station 104 configured to feed the shaping station 102 with the substrates 17 in a flat configuration, preferably precut, to be worked in order to obtain the products 12, for example, as mentioned, cardboard boxes.

The laser printing station comprises a movement member 14, configured to move the products 12 in a direction of advance X in coordination with the productivity of the shaping station 102, with which there is associated at least one laser printing device 30 configured to emit a laser beam L able to imprint a printed code on a layer of photosensitive paint present on a corresponding product 12 in transit in the direction of advance X.

The printed code can be a sequential number, a bar code, a QR code or other numerical sequence or image preferably suitable for the recognition of the product 12.

The apparatus 100 comprises a station 103 configured to deposit the layer of photosensitive paint on one or more areas 11 of the surface of the substrates 17. This station 103 can be located upstream or downstream of the feeding station 104. In this case, by way of a non-limiting example, this station is shown upstream of the feeding station 104.

The photosensitive paint has a composition (for example, pigment class, pigment concentration, type of solvent, etc.), with characteristics that give it a viscosity, absorption times, drying times (when deposited on corrugated cardboard), which allow to obtain a layer of photosensitive paint with characteristics suitable to be hit by a laser beam L and generate a print.

In order to move the products 12 in coordination with the productivity of the shaping station 102, it is necessary for the photosensitive paint to have a composition calibrated to the speed of movement of the products 12 in order to supply to the laser beam L a layer of photosensitive paint suitable to form the desired print when hit by the incident laser beam L.

The type of laser beam L generated by the laser printing device 30 is selected to cooperate with the type of photosensitive paint, that is, to induce the formation of a print.

The architecture of the laser printing device 30, for example, type, conformation, geometry, etc. of the optical elements is selected to emit a laser beam L with desired characteristics for the purposes.

The calibration between the characteristics of the laser beam L and those of the photosensitive paint, in such a way that these are adjusted with respect to each other, allows to obtain prints on a line with high production of cardboard.

In preferred embodiments, the laser printing device 30 comprises a CO ₂ laser.

The station 10 comprises a command and control unit 34 configured to control the at least one laser printing device 30 in order to emit a predetermined laser beam L. The laser beam L can correspond to a specific printed code for each of the products 12 which, on each occasion, advance on the movement member 14.

The command and control unit 34 can be configured to ensure that for each product 12 it is possible to imprint a specific printed code.

For example, it is possible to supply products 12, each bearing an identification code, possibly univocal, which allows their recognition and/or counterfeiting by appropriately configuring the command and control unit 34. In particular, the command and control unit 34 is configured to generate, with the movement member 14 in action, and, therefore, once production has started, the type of print to be imprinted on each carton 12.

In some embodiments, it is possible to configure the command and control unit 34 to modify the print without needing to stop the machine.

The speed with which the products 12 move along the movement member 14 requires the laser printing device 30 to generate a laser beam L only when the product 12 is in a correct position, that is, the position in which the photosensitive layer is in the emission trajectory provided by the laser beam L.

In some embodiments, the station 10 comprises a plurality of sensor devices 38 connected to the command and control unit 34 configured to detect the position of the product 12 on the movement member 14 in order to synchronize the emission of the laser beam L by the at least one laser printing device 30.

In some embodiments, each sensor device 38 can be an optical detection device, for example a video camera which as a whole can constitute a viewing system with video cameras managed by the command and control unit 34.

The optical detection device has acquisition performances suitable for the purposes in terms, for example, of acquirable frames per second.

In some embodiments, the laser printing device 30 comprises a laser head 32 configured to emit the laser beam L with a desired pattern corresponding to a specific printed code.

The laser head 32 is positioned on a support 36 along the movement member 14 in an advantageous position so that the laser beam L emitted incises the layer of photosensitive paint effectively.

In some embodiments, the laser head 32 can be mounted on an automatic orientable device (not shown) also controllable by the command and control unit 34 to orient the direction of the laser beam L emitted.

In some embodiments, the apparatus 100 can comprise movement members configured to move the at least one laser printing device 30 in the direction of advance X in coordination with the transit of the product 12 in order to execute an in-motion printing.

In some embodiments, the station 10 comprises more than one laser printing device 30 to supply more than one laser head 32. A greater number of laser devices 30 allows to simultaneously print wider areas of the product 12 or positions that, when the product is finished, can correspond to different sections or parts of the finished product itself.

By way of example, figs. 1 and 2 show the shaping station 102 configured to fold the product 12 in correspondence with two folding axes that identify two external portions 12a, 12b to be folded and a central portion 12c.

By way of example, the two external portions 12a, 12b are gradually folded inward until they are overlapping the face of the central portion 12c.

In possible variants, the laser heads 32 are positioned in such a way as to emit a laser beam L incident on opposite faces of the same product 12, for example on one or both portions 12a and 12b and/or on the portion 12c. In other possible variants, the laser heads 32 are positioned in such a way as to emit a light incident toward the same face.

The movement member 14 supplies a rest plane Q on which to position the products 12, preferably in a flat configuration.

In some embodiments, the movement member can comprise two conveyor belts 18 with an oblong development distanced and parallel with respect to each other or, alternatively, it can comprise an assembly of rollers and belts.

In some embodiments, the shaping station 102 is configured to form boxes and comprises a folding assembly 20 associated with the movement member 14 and configured to receive and fold cardboard sheets in one or more points along a folding axis parallel to the direction of advance X, in order to form such boxes. The laser printing station 10 is associated with the folding assembly 20 along the movement member 14.

In accordance with some embodiments, the shaping station 102 comprises a folding station as shown by way of example in the attached drawings.

The folding occurs gradually while the product 12 advances along the movement member 14 in order to obtain a folded product 12 with two substantially overlapping faces.

Preferably, the products 12 are positioned on the movement member 14 in such a way that the longitudinal development of the corrugations coincides with the line of advance X.

The folding assembly 20 comprises two pairs of folding units 22, each associated with a respective conveyor belt 18. Each folding unit 22 comprises a longitudinal member 24 and a folding guide 26. Each longitudinal member 24 develops mainly parallel to the conveyor belt 18 and is positioned at a distance substantially complementary to the thickness of the product 12.

Each longitudinal member 24 is positioned so as to contact a surface of the product 12 in correspondence with which it defines the folding line of the product 12, since it acts as a hinging axis during the folding movement of the portions to be folded, which from the folding line develop toward the outside.

The folding guide 26 is an oblong element such as a bar, and it is configured to take delivery of the product 12, in particular contacting the portions to be folded making them rotate along the folding axis toward the inside.

In particular, each folding guide 26 develops longitudinally, converging toward the center of the movement member 14 with respect to a direction of advance R1 of the product 12, see fig. 1. Each folding guide 26 is also suitably inclined from the bottom upward in the direction Rl.

The folding assembly 20, as well as producing an effective fold of the product 12, contributes to positioning the product 12 in a precise way in view of the station 10 where the laser printing device 30 is present.

In some embodiments, the product 12 rests on the rest plane Q in such a way that the at least one portion to be folded projects from the conveyor belt 18. During the advance along the line of advance X, the product 12 engages the longitudinal member 24 with one face and the folding guide 26 with the opposite face, the folding guide 26 causing, by virtue of its development, the portion to lift by pivoting on the longitudinal member 24 until it is overturned onto the flat face of the product 12. Typically, each of the overlapping faces will generate, once the product is finished, two faces of one box.

The invention also concerns a method for the in-line production and printing of cardboard products 12, which provides to carry out, directly downstream of the manufacturing of said products 12, a laser printing of products 12 which advance in the direction of advance X in coordination with the productivity of the manufacturing of the products 12 by emitting a laser beam L which imprints a printed code on a respective layer of photosensitive paint present on a corresponding product 12 in transit in the direction of advance X. In some embodiments, the method provides to gradually fold the products 12 in one or more points along a folding axis parallel to the line of advance X by means of a folding assembly 20 in order to obtain folded products 12 with two substantially overlapping faces. It is clear that modifications and/or additions of parts or steps may be made to the apparatus 100, to the station 10 and to the method as described heretofore, without departing from the field and scope of the present invention as defined by the claims.

In the following claims, the sole purpose of the references in brackets is to facilitate reading: they must not be considered as restrictive factors with regard to the field of protection claimed in the specific claims.