EP1737658B1 - Method for applying a film - Google Patents

Abstract

The device has a coating module transferring imaging layers of a bearing foil on a printing paper. The module contains an impression cylinder (4) and a pressing roller (3), which together form a combined transfer crack (6). A transfer foil (5), provided in the area of a foil routing device for guiding the transfer foil to a transfer crack, is attached with a device for application of the layers and/or information containing imprints. An independent claim is also included for method for coating of printed sheets in a sheet of paper processing machine.

Description

The invention relates to a device and a method for transferring imaging layers from a carrier foil to printed sheets according to the preamble of claims 1 and 6.

It is known to produce metallic layers on printed sheets by means of a film transfer process. So is in the EP 0 569 520 B1 a printing material and a printing apparatus using this material are described. In this case, a sheet-processing machine is shown, which has a feeder and a boom, wherein printing units and a coating module are arranged between the two units. In at least one of the printing units, an adhesive pattern is applied by means of the planographic printing process. This adhesive pattern is applied in a cold printing process and has a specific imaging subject. In the printing unit following the coating module with a counter-pressure cylinder and a press roller, a film guide is provided. This is designed in such a way that a film strip or a transfer film is guided through the transfer nip of the coating module between the impression cylinder and the press roll from a film supply roll. The film strip is rewound on the outlet side after leaving the coating module. The transfer film has a carrier layer on which imaging layers such as metallic layers, for example of aluminum, can be applied. Between the metallic layer and the carrier film, a separating layer is provided, which ensures that the metallic layer can be removed from the carrier layer.

When printing sheets are transported through the printing unit, each sheet is given an adhesive pattern. Thereafter, the sheet is passed through the coating module, being brought by means of the press roller on the impression cylinder resting sheet with the film material in combination. In this case, the downwardly lying metallic layer enters into a close connection with the areas provided with adhesive on the printed sheet. After further transporting the printing sheet, the metallic layer adheres only in the area provided with the adhesive pattern. The carrier film is thus removed from the metallic layer in the region of the adhesive pattern. The used in this way transfer film is wound up again. The print sheet is laid out in the coated state.
It is known to use such coating modules, for example in printing units of printing presses. A disadvantage of the known devices is that they can not be used flexibly.

It is still out WO 94/13747 known to use a pigmented adhesive for the transfer of imaging layers.

The object of the invention is therefore to provide a device by means of which the transfer of an image-forming layer, e.g. a metallization layer can be done on a sheet safely, economically and accurately, the device should be manageable for an extended range of applications.

The solution to this problem results in a device according to the features of claim 1 and in a method according to the features of claim 6.

Advantageously, the adhesive pattern for transferring the imaging layer from the transfer film is produced with a colored adhesive.

In this case, the image-forming layer on the transfer film can be transparent, semi-transparent, opaque or opaque.

The device can also be advantageously used in order to improve the use of the film by dividing the transfer film into one or more partial film webs of lesser width. In combination with the above-mentioned method, it is thus also possible to use different types of film side by side.
In this case adhesive patterns with different colors would then be usable.
Suitable application devices are well known.

The achievable effects extend over the compensation of the smallest imperfections, the enhancement of color effects, the combination or superposition of color effects of the adhesive and the imaging layer or the support of the gloss effect of the imaging coating.

To improve the gloss effect, the image-forming layer can be applied by means of so-called UV negative-pressure ink. The UV negative pressure ink is applied by means of the printing unit for the adhesive in a corresponding manner via an offset printing plate.

Advantageously, it is also possible to provide a plurality of coating modules behind one another within a sheet-processing machine. Thus, the application of different imaging coatings or metallization layers within a subject can take place one after the other. In this case, it is possible to transmit the imaging layers next to one another using a single adhesive pattern with all the image pattern elements. It is also possible to provide a first adhesive pattern in a first coating module with a first image-forming coating or metallization layer and, in the following, to apply another, the first enclosing adhesive pattern and to provide it with another image-forming coating or metallization layer.

In the following the invention is illustrated in more detail with reference to figures.

Figur 1

eine grundsätzliche Darstellung einer Druckmaschine mit einer Folientransfereinrichtung und

Figur 2

den Aufbau eines Beschichtungsmodules mit einer Folientransfer- einrichtung und

Figur 3

eine Presswalze eines Beschichtungsmodules und

Figur 4

eine Variante zum Aufbau eines Auftragwerkes.

Showing:

FIG. 1

a basic illustration of a printing machine with a film transfer device and

FIG. 2

the construction of a coating module with a film transfer device and

FIG. 3

a press roll of a coating module and

FIG. 4

a variant for the construction of a commissioned work.

• Ein zu beschichtender Druckbogen wird in einem ersten Arbeitschritt mit einem bildgebenden Klebstoffmuster versehen. Der Auftrag des Klebers erfolgt im einer als Auftragwerk 1 konfigurierten Vorrichtung, z.B. einem konventionellen Druckwerk einer Offsetdruckmaschine über dort vorhandene Farb- und Feuchtwerke 11, eine Druckplatte auf einem Plattenzylinder 12, einen Drucktuch- oder Gummizylinder 13 und einen Gegendruckzylinder 4.
  Gleichfalls sind hier Auftragwerke in Form von Flexodruckeinheiten oder Lackierwerken einsetzbar. Ein Variante zu einer derartigen Ausführungsform ist in Fig. 4 dargestellt ist. Der Kleber wird dort mittels eines Dosiersystems 21 über eine Rasterwalze 22 und eine Übertragwalze 23 auf einen Formzylinder 24 übertragen. Dieser trägt in diesem Fall eine Hochdruckplatte zur Erzeugung des bildgebenden Kleberauftrages.
• Danach wird in einem zweiten Schritt gemeinsam mit einem Druckbogen eine Transferfolie 5 durch einen Transferspalt 6 geführt, wobei die Transferfolie 5 im Transferspalt 6 gegen den Druckbogen gepresst wird. Hierzu wird ein Beschichtungsmodul 2 verwendet, das einem Druckwerk oder einem Lackmodul oder einer Basiseinheit oder einer andersartigen Verarbeitungsstation einer Bogenoffsetdruckmaschine entsprechen kann.
• Der Transferspalt 6 im Beschichtungsmodul 2 wird durch eine Presswalze 3 und einen Gegendruckzylinder 4 gebildet.
  Hierbei kann die Presswalze 3 einem Drucktuchzylinder und der Gegendruckzylinder 4 einem Gegendruckzylinder eines an sich bekannten Offsetdruckwerkes entsprechen.
  Weiterhin kann die Presswalze 3 einem Formzylinder und der Gegendruckzylinder 4 einem Gegendruckzylinder eines Lackmodules einer Bogendruckmaschine entsprechen.
• Weiterhin kann dem Beschichtungsmodul 2 nachgeschaltet ein so genanntes Kalandrierwerk vorgesehen werden, wenn der beschichtete Druckbogen zur Steigerung der Haftung der Beschichtung bzw. zur Steigerung von Glätte und Glanz des Druckbogens unter erhöhtem Druck überwalzt werden soll.

In FIG. 1 is a sheet-processing machine, here a printing press, shown, which consists of at least two printing units. The two printing units are used for the following purposes:

• A sheet to be coated is provided in a first step with an adhesive imaging pattern. The application of the adhesive takes place in a device configured as an applicator 1, for example, a conventional printing unit of an offset printing press on there existing inking and dampening 11, a printing plate on a plate cylinder 12, a blanket or blanket cylinder 13 and a counter-pressure cylinder. 4
  Likewise, applicators in the form of flexographic printing units or coating units can be used here. A variant of such an embodiment is in Fig. 4 is shown. The adhesive is transferred there by means of a dosing system 21 via an anilox roller 22 and a transfer roller 23 to a forme cylinder 24. This carries in this case a high pressure plate for generating the imaging adhesive application.
• Thereafter, in a second step, together with a printing sheet, a transfer film 5 is guided through a transfer nip 6, wherein the transfer film 5 is pressed in the transfer nip 6 against the printing sheet. For this purpose, a coating module 2 is used which can correspond to a printing unit or a lacquer module or a base unit or another type of processing station of a sheet-fed offset printing press.
• The transfer nip 6 in the coating module 2 is formed by a press roll 3 and an impression cylinder 4.
  Here, the press roller 3 a blanket cylinder and the impression cylinder 4 correspond to a counter-pressure cylinder of a known offset printing unit.
  Furthermore, the press roll 3 a form cylinder and the impression cylinder 4 correspond to a counter-pressure cylinder of a varnish module of a sheet-fed press.
• Furthermore, downstream of the coating module 2, a so-called calendering unit can be provided if the coated printing sheet is to be rolled under increased pressure to increase the adhesion of the coating or to increase the smoothness and gloss of the printed sheet.

Within the coating module 2 used for the film transfer, a web guide for transfer films 5 is shown.
For processing in question transfer sheets 5 are constructed in multiple layers. They have a carrier layer on which an imaging layer is applied by means of a release layer. The separating layer serves to facilitate lifting of the imaging layer from the carrier layer. The image-forming layer may be, for example, a metallized layer or a glossy layer or a texture layer or a colored layer or a layer containing one or more image patterns.

The film supply roll 8 is assigned to the coating module 2 on the sheet feed side. The film supply roll 8 has a rotary drive 7. The rotary drive 7 is required for the continuous controlled feeding of the transfer film 5 to the coating module 2 and is therefore controllable.
Furthermore, in the field of film feed and removal guide devices 14, such as deflection or tensioning rollers, pneumatically actuated conducting means, baffles o. Ä. Provided. Thus, the film web of the transfer film 5 can always be performed flat without distortion and held in the same voltage against the press roller 3. The guide devices 14 may also contain aids for introducing the transfer film 5. In this case, automatic retraction aids for the film web of the transfer film 5 can be used.
In this way, the film feed in the area of the coating module 2 surrounding Verschutzungen 15 is simplified. The protective function of the Verschutzungen 15 is maintained at the same time completely.

In this case, the transfer film 5 can be guided around the press roll 3, wherein the transfer film 5 can advantageously be fed and discharged from the press nip 6 only from one side of the coating module 2 (see dashed representation). The film web may differ from the illustration to Fig. 1 and depending on the space conditions on the one side of the coating module 2 advantageously in the feeding strand and the laxative strand are guided closely parallel to each other.
In a further embodiment, the transfer film 5 can also be fed in and out substantially tangentially on the press roll 3 or wrap it around the press nip 6 only in a small circumferential angle. For this purpose, the transfer film 5 is supplied from one side of the coating module 2 and discharged to the opposite side of the coating module 2.

On the outlet side of the printing unit, a film collection roller 9 is shown. On the film collecting roll 9, the used film material is wound up again. Again, a rotary drive 7 is provided for the optimized production, which is controllable. In essence, the transfer film 5 could also be moved by the rotary drive 7 on the outlet side and kept taut on the inlet side by means of a brake.

For the transfer process of the imaging eg wear layer of the transfer sheet 5 on the sheet in the transfer nip 6 between the press roll 3 and the impression cylinder 4 is essential that the surface of the press roll 3 so the blanket cylinder or forme cylinder is equipped by means of a compressible, damping element.
The press roll 3 is therefore provided with a press fabric 10 or as a roll with a corresponding coating. The press fabric 10 or press coating can be performed, for example, as a plastic coating, comparable to a blanket or blanket. The surface of the press fabric 10 or press coating is preferably very smooth. It can also be formed from antiadhesive substances or structures. Here, for example, a relatively hard structure in the form of very fine spherical caps comes into question. A Press fabric 10 is held on the press roll 3 in a cylinder channel on jigs.
The press fabric 10 may be equipped to improve the transmission properties in the transfer nip 6 with a targeted elasticity. This may optionally act in a compressible intermediate layer. This compressibility is preferably similar or less than in conventional blankets or Drucktüchem that can be used at this point.
The mentioned compressibility can be produced by means of a conventional compressible printing blanket. Furthermore, combined fabrics made of a hard blanket and a soft pad can be used.
Furthermore, a limited pressing surface can be provided directly on the press roll 3 or on the press fabric 10. This can be worked out of the surface of the press fabric 10 or it can be additionally attached as a partial surface of the material of the press fabric 10 on the press roller 3.

• Hierzu kann eine Steuerung der Transferfolie 5 derart erfolgen, dass beim Durchlaufen eines Greifer des bogenführenden Gegendruckzylinders 4 aufnehmenden Zylinderkanales der Folienvorschub angehalten wird. Die Greifer halten den Druckbogen auf dem Gegendruckzylinder 4. Die Presswalze 3 weist einen dazu korrespondierenden Zylinderkanal 19 (siehe Fig. 3) auf, in dem eine Pressbespannung 10 gehaltert ist. Im Bereich der korrespondierenden Zylinderkanäle erfolgt keine Pressung der Transferfolie 5 zwischen der Presswalze 3 (Drucktuchzylinder) und dem Gegendruckzylinder 4. Die Presswalze 3 läuft dann an der Transferfolie 5 gleitend weiter, während die Transferfolie 5 zwischen Presswalze 3 und Gegendruckzylinder 4 frei liegend gespannt ist. Dieser Zustand dauert an bis am so genannten Druckanfang der Zylinderkanal 19 endet und die Transferfolie 5 erneut zwischen der Presswalze 3 und dem Gegendruckzylinder 4 unter Einschluss eines Druckbogens eingeklemmt wird. Dann wird die Transferfolie 5 weiter transportiert. Die Taktung des Folienvorschubes kann entsprechend einer notwendigen Beschleunigung bzw. Bremsung der Folienvorratsrolle 8 bzw. Foliensammelrolle 9 etwas früher beginnen bzw. aussetzen als dies die Kanalkanten des Zylinderkanals vorgeben. Bei reaktionsschnellen Taktungssystemen über so genannte Tänzerwalzen 18, wie sie beispielhaft in Figur 1 eingezeichnet sind, ist die Steuerung der Drehantriebe 7 der Folienvorratsrollen 8 bzw. Foliensammelrolle 9 ggf. nicht erforderlich. Mittels der Tänzerwalzen 18 wird ebenfalls die notwendige Folienspannung aufrecht erhalten.

To improve the efficiency of the coating process, it is provided that the film advance of the transfer film 5 from the film supply roll 8 to the transfer nip 6 and the film collection roll 9 is controlled so that as far as possible the transfer film 5 is stopped when no transfer of the imaging layer should take place :

• For this purpose, a control of the transfer film 5 can be made such that the film feed is stopped when passing through a gripper of the sheet-guiding counter-pressure cylinder 4 receiving cylinder channel. The grippers hold the sheet on the impression cylinder 4. The press roll 3 has a corresponding cylinder channel 19 (see Fig. 3 ), in which a press fabric 10 is held. In the region of the corresponding cylinder channels, there is no pressing of the transfer film 5 between the press roll 3 (blanket cylinder) and the impression cylinder 4. The press roll 3 then continues to slide on the transfer film 5, while the transfer film 5 is stretched freely between the press roll 3 and impression cylinder 4. This state continues until at the so-called pressure start of the cylinder channel 19 ends and the transfer sheet 5 is again clamped between the press roller 3 and the impression cylinder 4, including a sheet. Then, the transfer sheet 5 continues transported. The timing of the film feed can begin or suspend slightly earlier than pretend the channel edges of the cylinder channel according to a necessary acceleration or braking of the film supply roll 8 or film collecting 9. In reaction-fast timing systems via so-called dancer rollers 18, as exemplified in FIG. 1 are shown, the control of the rotary actuators 7 of the film supply rolls 8 and film collecting roll 9 may not be necessary. By means of the dancer rollers 18, the necessary film tension is also maintained.

A further improvement of the film utilization of the type described results from the fact that the transfer film 5 is divided into one or more Teitfotienbahnen lesser width. Thus, with appropriate control by means of the device or devices for timing the film feed each of the sub-film webs, the utilization of the transfer film 5 can be improved even in zonally different lengths coating areas within an arc. For this purpose, each partial film web is conveyed only exactly in the area where the imaging surface layer is to be applied. In the areas not to be coated, each partial film web can be stopped independently of the other partial film webs, whereby no unnecessary film consumption arises.

Furthermore, to improve the coating process provided in the area of the adhesive application and in the area of the film order dryer 16 provided. Thus, in particular by means of UV drying, the imagewise applied adhesive layer can be predried by means of a first dryer 16 (intermediate dryer I), so that the wear layer of the transfer film 5 adheres better. Furthermore, the adhesive effect of the applied wear layer on the printed sheet can be improved by the action of a second dryer 16 (intermediate dryer II) by additionally accelerating the drying of the adhesive.

Finally, the quality of the coating can be controlled by means of an inspection or monitoring device 17 after the foil application. For this purpose, the inspection device 17 is on a sheet-guiding surface of the coating module 2 after the transfer nip 6 and optionally abgeschottet of the dryer 16 or be directed to a sheet-guiding surface of the coating module 2 downstream further sheet leading module. The pre-applied coated printing sheet can thus be checked for completeness and quality of the coating. As poorly recognized printed sheets can be marked or rejected in a sorter as waste.

According to Fig. 2 For example, the coating module may be provided with means for conditioning the transfer film in order to improve the layer transfer and the coating result. In this case, the film web 5 can be influenced by means of the film guiding device 14.

To support the optical effect of the layer application of the transfer films, it can be provided according to the invention that the adhesive layer taking over the application of the imaging layer receives a corresponding coloring. For this purpose, the adhesive layer may be colored in silver-colored or glossy films in a gray tone. For example, when using gold-colored or glossy metal foils, the adhesive layer may be colored in a yellow tint. Thus, the effect of the imaging layer against the color of the pad surface is supported on the sheet in the desired manner.

Furthermore, a support of the color effects of the imaging coating is achieved by the colored adhesive layer. This makes it possible to use cost-effective films on the one hand. The imaging layer may be so complete or semitransparent, opaque or opaque.

• den Ausgleich kleinster Fehlstellen in der bildgebenden Beschichtung auf dem Druckbogen, durch optischen Ausgleich der Farbwirkung bzw. Abdeckung der Farbe des unterliegenden Druckbogens,
• die Verstärkung von Farbeffekten in transparenten oder teiltransparenten bildgebenden Beschichtungen, durch additive Wirkung der Färbung der Kleber schicht und der Beschichtung auf dem Druckbogen,
• die Kombination bzw. Überlagerung von Farbeffekten des Klebers und der bild gebenden Beschichtung, durch Mischung der Farbwirkungen der Färbung der Kleberschicht und der Beschichtung auf dem Druckbogen oder
• die Unterstützung von Glanzeffekten der bildgebenden Beschichtung, durch zusätzliche Glanzwirkung der Kleberschicht bei transparenten oder durchscheinenden Beschichtungen auf dem Druckbogen.

The achievable effects extend to the following applications:

• the compensation of the smallest imperfections in the imaging coating on the printed sheet, by optical compensation of the color effect or coverage of the color of the underlying printed sheet,
• the enhancement of color effects in transparent or semi-transparent imaging coatings, by additive effect of the coloring of the adhesive layer and the coating on the printed sheet,
• the combination or superposition of color effects of the adhesive and the image-forming coating, by mixing the color effects of the coloring of the adhesive layer and the coating on the printing sheet or
• The support of gloss effects of the imaging coating, by additional gloss effect of the adhesive layer in transparent or translucent coatings on the sheet.

Consequently, the optical effect of the imaging coating can also be subsequently influenced. In this case, the range of application of standardized transfer foils 5 in the production of high-quality coatings with the cold foil stamping method can advantageously be expanded.

In order to improve the gloss effect, reference should again be made in this connection to the application of the imaging layer by means of an adhesive which reacts to ultraviolet radiation. Here, colorless or dyeable UV negative-pressure ink can be applied. This UV negative pressure ink is applied by means of the applicator 1 for the adhesive in a corresponding manner via an offset printing plate. This results in improved smoothness and thus gloss effect of resting on the sheet imaging layer. Thus, the adhesive effect of the UV negative pressure ink can be fully utilized and the smoothness of the coating is increased.

LIST OF REFERENCE NUMBERS

1

commissioned

2

coating module

3

press roll

4

Impression cylinder

5

Transfer foil / foil web

6

transfer nip

7

roller drive

8th

Film supply roll

9

Foil composite role

10

Press covering

11

Inking / dampening unit

12

plate cylinder

13

Blanket / blanket cylinder

14

Folienleiteinrichtung

15

Printing plant security

16

dryer

17

Inspection device / monitoring system

18

dancer roll

19

cylinder gap

20

Press area

21

dosing

22

anilox roller

23

Transfer roll

24

form cylinder

Claims (8)

1. A device for the transfer of imaging layers on print sheets with an application system (1), a coating module (2), an adhesive and a transfer foil (5), which is formed by a substrate foil and the imaging layers, wherein the application system (1) is equipped for the image coating of the print sheets with the adhesive and the coating module (2) is equipped for the transfer of the imaging layers from the substrate foil on to the print sheet in a transfer gap (6) between an impression cylinder (4) and a press cylinder (3), wherein the substrate foil can be guided with the coated side in contact with the print sheet jointly with said print sheet can be guided through the transfer gap (6) and the imaging layers can be transferred on to the print sheet in accordance with the image, wherein
   as application system (1) an offset printing system or flexographic printing system or coating system having a printing plate is provided, wherein in the application system (1) an inking system (11) in conjunction with a plate cylinder (12) carrying a printing plate or a dosing system (21) in conjunction with a form cylinder (24) carrying a letterpress plate is provided to create the imaging adhesive application and that the inking system (11) or the dosing system (21) are embodied for supplying the adhesive, characterized in that the adhesive for enhancing the visual effect of the layer application of the transfer foils (5) on the print sheet, the adhesive layer which assumes the application of the imaging layer or the metallising layer has a colouration which corresponds to the imaging layer or enhances the colouration of said layer and that an offset printing system or a varnish module is used as coating module (2).
2. The device according to Claim 1,
   characterized in
   that the imaging layer is applied by means of an adhesive which can be dried by means of ultraviolet radiation.
3. The device according to Claim 2,
   characterized in
   that as adhesive a UV-vacuum ink is used and that said vacuum ink can be applied in accordance with the image by means of the application system (1) for the adhesive by way of an offset printing plate.
4. The device according to Claim 2 and 3,
   characterized in
   that in sheet transport direction between the application system (1) for the adhesive and the coating module (2) a UV-dryer (16) is provided, by means of which the image layer of the UV-vacuum ink is at least pre-dried after the application on to the print sheet and before the transfer of the imaging layer.
5. The device according to Claim 1 to 4,
   characterized in
   that the coating module (2) is assigned a UV-dryer (16) in such a manner that by means of the UV-dryer (16) the layer according to the image of the UV-vacuum ink can be dried after the transfer of the imaging layer.
6. A method for the transfer of imaging layers from a transfer foil (5) comprising a substrate foil and the imaging layer/s on to print sheets in a sheet-processing machine at least with an application system (1) for the coating in accordance with the image of the print sheets with an adhesive and with a coating module (2) for transferring the imaging layers from the transfer foil (5) on to the print sheet in a transfer gap (between an impression cylinder (4) and a press cylinder (3), wherein the transfer foil (5) with the coated side in contact with the print sheet is jointly guided through the transfer gap (6) and in the process the imaging layers according to the image are transferred on to the print sheet, wherein
   the adhesive is applied in an application system (1) which is provided as an offset printing system or flexographic printing system or coating system having a printing plate, wherein in the application system (1) an inking system (11) in conjunction with a plate cylinder (12) carrying a printing plate or a dosing system (21) in conjunction with a form cylinder (24) carrying a letter press plate for creating the imaging adhesive application is provided, and that the adhesive is supplied by means of the inking system (11) or the dosing system (21), characterized in
   that as adhesive a coloured adhesive is used and that the adhesive has such a colouration that through the adhesive layer an enhancement of the visual effect of the layer application of the transfer foils (5) on the print sheet is achieved in such a manner that the adhesive layer assuming the application of the imaging layer or the metallising layer has a colouration which increases the gloss effect of the imaging layer or offsets defects in the imaging layer or metallising layer, and that the imaging layer is transferred from the transfer foil (5) on to the print sheet by means of a press clothing or press coating on the press cylinder (3).
7. The method according to Claim 6,
   characterized in
   that the adhesive layer and/or the imaging coating is exposed to UV-radiation for drying.
8. The method according to Claim 6 or 7,
   characterized in
   that the print sheet in one or a plurality of printing systems is provided with a uni-colour or multi-colour print image after coating by means of the transfer foil (5).

Images