FR2832093A1 - High resolution labeling uses numerical electro-photography, on a film which has been oxidized and coated with a binder/glue, to be applied to the product surface by in-mold labeling - Google Patents

Abstract

To produce a single unit or a small series run of a label with a high resolution printed image, which is unique or variable, the image is printed numerically by electro-photography (30) on one surface of a plastics film. The film is compatible with the product, and has previously been oxidized (10) and coated with a binder or glue (20) and dried by infra red or hot air heating. The printed film is applied to the product at a mold (70), using an in-mold labeling (IML) technique, at a temperature of \-50 deg C.

Description

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METHOD FOR MANUFACTURING THE UNIT OR IN A SMALL SERIES OF A
PRODUCT WITH A UNIQUE OR VARIABLE PRINTED IMAGE
The present invention relates to the field of printing single or variable images on flat or raised objects.

 The present invention relates more particularly to a method of manufacturing individually or in small series of a product having a high resolution image, printed, single or variable. The concept of small series will obviously be understood by those skilled in the art as designating a small quantity compared to the field of application of the invention considered.

 The prior art already knows methods for manufacturing individually or in small series of a product having a unique or repetitive printed decorative element, but these methods either do not make it possible to achieve the required printing quality, or are too expensive to be applied to small series or even unit prints.

 The prior art also knows the French patent application FR 2 750 080 which presents a method of decorating an object using an image, in which the image is printed using a printer. ink jet on a support film previously coated with an adherent coating and in which the printed side is then brought into contact with the object. The support film is then subjected to a high temperature, so that the adhesion of the coating is activated and causes the adhesion of the image on the decorated object.

 This technique is based on the fact that the support film is a plastic material not compatible with the material to be decorated, that is to say that when the support

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 plastic and the object to be decorated are in contact and the support is heated, the latter does not adhere to the object to be decorated, no bond being created between the two materials.

 A major drawback of this technique is that the essential step during which the printing leaves the support to adhere to the product is very delicate. Variation of parameters or movement of the mold during this step can cause deterioration of the print.

 In addition, the quality of printing is limited due to this transfer and the type of printing: inkjet printing. It is not possible to print at high resolution.

 The present invention intends to remedy the drawbacks of the prior art by proposing an inexpensive process which makes it possible to produce, with a high printing quality, prints in small series or even individually on flat or three-dimensional objects requiring a setting step. in shape, after printing, including a passage of the object thus marked at a high temperature (above 50 C).

 In addition, the present invention intends to propose carrying out the printing of the image on a support intended to be positioned in or on the finished object.

 By three-dimensional objects, of course we mean objects which are not flat and have non-negligible dimensions in the three axes of space.

 To do this, the present invention is of the type described above and it is remarkable, in its broadest sense, in that said decorative element is printed by electrophotographic digital printing.

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 on one side of a plastic film compatible with the material of said product to be decorated; the non-adhesive film having previously undergone a pre-grip treatment and said product being intended to undergo a shaping step comprising a passage of the product thus decorated at a temperature above 50 ° C., in particular for setting three-dimensional shape of said object.

 Said printing is preferably carried out continuously from a film in the form of a roll.

 In a variant of the invention, said digital printing is carried out on a second face of said film, transparent, mirrored and the film then produces a protective layer for printing.

 Prior to the bonding pre-treatment step, said film undergoes an oxidation treatment.

 After the digital laser printing step and prior to the shaping step, said film preferably undergoes a screen printing step.

 In a preferred version of the invention, after screen printing, the film is dried using ultraviolet radiation, in order to allow the production rate to be increased.

 Before the shaping step, said product preferably undergoes a printing protection step.

 The different steps of the method according to the invention can be carried out on different machines, between the steps of pre-treatment of grip and shaping, said film then undergoes at least one shaping in the form of a roll.

 Prior to the shaping step, said film is preferably cut during a cutting step, in order to produce at least one label.

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 An important advantage of the invention lies in the fact that the printing thus produced exhibits characteristics of significant resistances, in particular at temperature and pressure, and thus makes it possible to carry out a three-dimensional shaping step which is difficult for the film. .

 Indeed, the printing resists a temperature up to 3000C and a pressure up to 1700 bars.

 Advantageously also, the plastic film can be chosen from a wide range of different products and can be based on: polycarbonate, polystyrene, polypropylene, polyethylene, including polyethylene terephthalate, polyvinyl chloride, polymethyl methacrylate, polyester ,. .. or be a complex (mixture or multilayer) of these products.

 In addition, since the film is integrated into the product to be decorated, the shaping step can be a very restrictive and delicate step, this has no influence on the print quality and the resolution.

 The shaping step can thus be a bonding step by coating on a flat product or a three-dimensional shaping step by the method of positioning labels in the IML mold (In Mold Labeling) on the external or internal face. of the object, by thermoforming possibly associated with the IML method, lamination, heat sealing, ...

 Advantageously finally, the present invention allows objects to be produced individually or in small quantities, presenting identical or variable images, at a high rate.

 The present invention also relates to the device allowing the implementation of the manufacturing process according to the invention, as well as to the label and to the

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 product having at least one label producing a high resolution image, obtained by implementing the manufacturing method according to the invention.

 The invention will be better understood with the aid of the description, given below for purely explanatory purposes, of an embodiment of the invention, with reference to the appended figures: FIG. 1 illustrates a flow diagram of the method according to the invention; m FIG. 2 illustrates the stages of oxidation and pre-treatment of attachment of the support; FIG. 3 illustrates the step of digital printing of the image by electrophotography; in FIG. 4 illustrates the screen printing step and FIG. 5 illustrates the steps of protecting the support and cutting.

 The manufacturing method according to the invention, illustrated in FIG. 1, is a method of manufacturing individually or in small series of a product having a high resolution image, printed, unique or variable.

 The method according to the invention is characterized in that said decorative element is printed by digital electrophotographic printing (30) on one side of a film (1) of plastic material compatible with the material of said product, non-adhesive, having previously undergone a pre-treatment of grip (20), said product being intended to undergo a shaping step (70) comprising a passage of the product thus decorated at a temperature above 50 C, in particular for a three-dimensional shaping of said object .

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 Digital printing is carried out over the entire width of the film (1), from a film (1) in the form of a roll (2,3, 4,5, 6). An important advantage of manufacturing from rollers is that the consequences of electrostatic charges are felt less on the rollers than on the stacks.

 Digital printing is carried out continuously, but can of course be interrupted between the printing of each label. Printing is very fast and changing the print pattern has no influence on the rate, even when each print is different from the previous and the next.

 Digital printing (30) can be carried out on the outer face of the film (1) relative to its future position on the product, face called first face o, or can be carried out on the inside face of the film (1) called second face, mirrored, when the film (1) is transparent.

 The advantage of the second variant is that the film (1) then constitutes a protective layer for the printed image against external aggressions that the final object can undergo.

 The method according to the invention can also comprise the following steps, whatever the face on which the printing is carried out: prior to the grip pre-treatment step (20), said film (1) undergoes an oxidation treatment (10); '' After the digital printing step (30) and prior to the shaping step (70), said film undergoes an optional screen printing step (40) using a screen printing device (41 );

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 'Before the shaping step (70), said product undergoes an optional step of protecting (50) printing on the first or second side, for example by varnishing or film-coating, in order to improve its resistance to 'abrasion and chemical attack; 'Prior to the shaping step (70), said film is cut during a cutting step (60) to form labels (61), in order to allow the flat or three-dimensional processing of the film.

 The oxidation treatment (10), illustrated in FIG. 1, can be a Corona treatment, in which the film (1) passes between at least one electrode (11) and a charging cylinder (12) charged with a potential different from that of the electrode, in order to carry out an ozonization of the air, then, consequently, an oxidation of the surface of the film.

 The oxidation treatment (10) can be a flame treatment (not illustrated) in which the film passes near a flame which also causes surface oxidation of the film, or else a treatment by passage through one or more baths acid (also not shown).

 The purpose of this oxidation treatment (10) is to make it possible to increase the surface tension of the surface of the film in order to create polar groups promoting the adhesion of the product used during the pre-treatment of grip.

 Thanks to this oxidation treatment, the surface tension, for example of a polycarbonate film, can thus pass from a value less than 36 dynes to a value of approximately 42 dynes.

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 The pre-treatment of grip (20), also illustrated in FIG. 1, consists in passing the film (1), coming from the roller (2) between a counterpressure cylinder (21) and a sleeve (22), in contact with these, said sleeve (22) being in contact with a third roller (23) bubbling in a tank containing a bonding product (24), such as a binder or an adhesive, in order to produce a fine and homogeneous deposit of bonding product (24), of at least 0.3 g / m2 on the face of the film previously oxidized and allowing the impression to cling to the film.

 The applied bonding product (24) is then preferably dried using infrared radiation (25) before digital printing or by hot air.

 After these first two steps, the film (1) can be wound on a roll (3).

The digital electrophotographic color printing (30) in liquid ink, illustrated in FIG. 3, is based on the following principle:
A Scoroton (31) (trade name designating a corona loading bar), loaded at approximately -800 Volts makes it possible to load a main drum (32), driven in rotation, at a value of approximately-750 Volts.

 For each color, a laser beam (shown in dotted lines), coming from a laser diode (33) is then sent to the surface of the main drum (32), in order to discharge it, at a value of approximately -100 volts, in the zones corresponding to the places in which we want to have the color to form the image. Then, an injector (34) sends liquid ink onto the surface of the main drum (32).

 In the course of its rotation, the main drum (32) comes into contact with a developer cylinder (35) charged at approximately -400 volts, charged with

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 recover the excess ink, then the main drum (32) transfers the ink of the color which remains on its surface on a blanket (36), or intermediate transfer cylinder, charged at + 500 volts.

 The cycle is then repeated for each other color. This type of printing allows the use of four to sixteen colors.

 Once the blanket (36) has all the layers of color, the image is transferred to the film (1) which passes between the blanket (36) and a back pressure cylinder (37).

 The printing speed can be around 6m / min or more.

 The optional screen printing step (40) allows a layer of white or matt or glossy varnish to be added to the print, using a screen printing device (41) in order to give it the desired finish.

 After screen printing, the film (1) preferably undergoes drying using ultraviolet radiation (42), in order to allow the film (1) to be advanced at a higher rate.

 The printing protection step (50), illustrated in FIG. 5, consists, as for the pre-treatment of grip (20), in passing the film (1), coming from the roll (5) between a cylinder back pressure (51) and a sleeve (52) in contact with them, said sleeve (52) being in contact with a third roller (53) bubbling in a tank containing a protection product (54), such than a varnish or a film, in order to achieve a fine and homogeneous deposit of protective product (54) on the face of the film previously printed.

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 The applied protection product (54) is then preferably dried using ultraviolet radiation (55).

 After this step, the film (1) can be wound on a roll (6).

 The cutting step (60) consists in cutting the film (1) coming from the roll (6), in order to produce labels (61).

 The shaping step (70) can consist in manufacturing a product containing at least one label by thermoforming. In this case, the label is pinched in a non-deformable frame and is heated until softened (depending on the composition of the support film). When the softening is sufficient, the label is sucked against a wall of the mold and the label then takes the form of the mold.

 The shaping step (70) can also consist in manufacturing a product containing at least one label by IML. In this case, the label is inserted into the mold and the material of the product is injected into the mold. The material of the substrate (product) is generally of the same type as the material of the support film.

 The shaping step (70) can also consist in manufacturing a product containing at least one label by heat sealing. In this case, the surface of the label and the surface of the product are heated and are pressed against each other in order to cause adhesion.

 The present invention also relates to the device allowing the implementation of the manufacturing method according to the invention. This device can consist of a single machine or of several machines, or even as many machines as there are stages referenced.

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 The present invention also relates to the individualized labels, in the form of a roll or board, obtained by the implementation of the manufacturing method according to the invention and to the products each having at least one label forming a high resolution image obtained by the implementation of the manufacturing process according to the invention.

 The invention is described in the foregoing by way of example. It is understood that a person skilled in the art is able to carry out different variants of the invention without going beyond the scope of the patent.

Claims (12)

1. A method of manufacturing individually or in small series of a product having a high resolution image, printed, single or variable, characterized in that said decorative element is printed by digital electrophotographic printing (30) on one side d '' a film (1) of plastic material compatible with the material of said product, non-adhesive, having previously undergone a pre-treatment of grip (20), said product being intended to undergo a shaping step (70) comprising a passage of the product thus decorated at a temperature above 50 ° C., in particular for three-dimensional shaping of said object.  2. Manufacturing method according to claim 1, characterized in that said digital printing (30) is carried out continuously from a film (1) in the form of a roll (2).  3. The manufacturing method according to claim 1 or claim 2, characterized in that said digital printing (30) is carried out on a second face of said film (1), transparent, mirrored.  4. Manufacturing method according to any one of claims 1 to 3, characterized in that prior to the pre-treatment step of grip (20), said film (1) undergoes an oxidation treatment (10) .  5. Manufacturing method according to any one of claims 1 to 4, characterized in that after the digital printing step (30) and prior to the shaping step (70), said film (1 ) undergoes a screen printing step (40).  6. The manufacturing method according to claim 5, characterized in that after the <Desc / Clms Page number 13>  screen printing, the film (1) is dried using ultraviolet radiation (42).  7. The manufacturing method according to any one of claims 1 to 6, characterized in that before the shaping step (70), said film undergoes a step of protecting (50) the printing.  8. Manufacturing method according to any one of claims 1 to 7, characterized in that between the oxidation treatment steps (10) and shaping (70), said film (1) undergoes at least one setting in the form of a roll (3,4,5,6).  9. Manufacturing method according to any one of claims 1 to 8, characterized in that prior to the shaping step (70), said film is cut during a cutting step (60), in order to make at least one label (61).  10. Device allowing the implementation of the manufacturing process according to any one of claims 1 to 9.  11. Label obtained by implementing the manufacturing process according to any one of claims 1 to 9.  12. Product having at least one high resolution image obtained by the implementation of the manufacturing process according to any one of claims 1 to 9.