DE102012218840A1 - Method for transfer of image transfer layer of transfer film on printed sheet in sheet-fed offset printing machine, involves overprinting sheet by introducing transfer and protective layers in surface expansion after drying protective layer - Google Patents

Abstract

The method involves transferring a subject of a transfer layer of a transfer film (5) to a printed sheet in a transfer gap (6) by pressing. A protective layer is applied on the transfer layer applied on the printed sheet by using inline-aggregates i.e. inkjet printheads. A drying process of the protective layer is performed on the printed sheet after applying the protective layer. The printed sheet is pictorially overprinted by introducing the transfer layer and the protective layer in part or total surface expansion after drying the protective layer.

Description

The invention relates to a method and a film transfer device for the transfer of imaging layers from a transfer film. A preamble to 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, between two units printing units and a coating unit are arranged. In at least one of the printing units, an adhesive pattern is applied by the planographic printing method to carry out a so-called cold foil transfer method.

When printing sheets are transported through the printing unit, each sheet is given an adhesive pattern. Thereafter, the sheet is passed through the coating unit, 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 units, for example in printing units of printing presses. A disadvantage of the known devices is that they are often not flexible enough to use.

The object of the invention is therefore to provide a device by means of which the transfer of an imaging layer to a sheet can be done economically and safely, the device should be easy to handle.

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

It is provided according to the invention, which apply a protective or release layer immediately after the film transfer or after the film transfer and before a subsequent overprinting so that when overprinting or further coating an imagewise provided with a transfer layer sheet transfer within the range of the transferred transfer layer no cleavage of Transfer layers can take place from the printing sheet to the printing units used for color or colorless overprinting.

Preferably, the protective layer is dried after application and before overprinting in other printing units or before repainting in other coating units by means of a drying device.

In this case, a protective layer can consist of a UV-curing medium and be irradiated by means of a drying device emitting a UV radiation to cure the protective layer.

The protective layer is preferably applied in a sheet-fed offset printing press by means of a printing unit or coating unit following in the sheet transport direction on the apparatus for cold foil transfer.

In a further development of the invention, the protective layer can be applied in a sheetfed offset printing press by means of an inline aggregate, which is assigned in the sheet transport direction to the device for cold foil transfer following a coating position.

In a particularly simple manner, the protective layer can be produced by means of a printing plate whose subject corresponds to the printing plate with which the adhesive layer for cold-foil transfer is applied in the applicator.

In this case, a lacquer or a binder or a primer can be used as the medium for the production of the protective layer.

Finally, the medium for producing the protective layer is advantageously adjusted in its composition to the printing inks or varnishes used for the further printing or varnishing of the printed sheets in the printing units or coating units following the cold foil transfer such that good adhesion of the further layers of printing ink to be applied is ensured on the protective layer.

Devices by means of which the method according to the invention can be carried out well can be designed differently.

In this case, a first device on one or more inkjet printheads, which the sheet according to the positions of the adhesive application in the applicator and the transfer layer on the Transfer film are assigned in the coating plant for coating the film areas. Therefore, the film image can be provided on the sheet specifically with the exception of further image areas with a protective layer.

A second device is designed as a coating unit or printing unit, in which a protective coating is applied to the printing sheet provided with the film image. In the painting or printing unit, a printing plate can preferably be used, as it is used in the corresponding printing process for the adhesive application.

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

1 : an overview of a sheet-fed printing machine with a film transfer device,

2 a sheet-fed printing machine with film transfer device and with a control station and

3 a diagram of a sheet-fed press with means for carrying out the method according to the invention.

In 1 a sheet-processing machine is shown, which consists of at least two printing or application works and preferably other printing and / or application works. This arrangement forms a film transfer device. A printing sheet is provided in the first printing or application work with an adhesive layer (applicator 1 ). Thereafter, in the following printing or application work together with a sheet a transfer film 5 with a transfer layer through a transfer nip 6 led, in which the transfer film 5 pressed against the sheet (coating 2 ).

The device can be arranged in a sheet-fed offset printing press. The commissioned work 1 is a well-known offset printing unit with an inking unit 11 a plate cylinder 12 , a blanket cylinder 13 and a sheet leading impression cylinder 4 be. It can also be designed as a paint module in which the blanket cylinder 13 is designed as a form cylinder. The forme cylinder is painted or glued by a device designed, for example, as a chamber doctor blade system instead of the inking unit 11 provided.

The transfer gap 6 in the coating plant 2 is through a press roll 3 and an impression cylinder 4 educated. Here, the press roller 3 the blanket cylinder and the impression cylinder 4 correspond to the impression cylinder of an offset printing unit. Furthermore, the press roll 3 the form cylinder and the impression cylinder 4 correspond to the impression cylinder of a paint module of a sheet-fed press.

For this purpose, finally, the coating plant 2 be designed as a base unit of a printing unit, so that only a counter-pressure cylinder 4 and a press roll 3 are present to the sheet transport and the transfer process in the transfer gap 6 perform in conjunction with appropriate to be provided Folienabund-curls.

The transfer foil 5 is multi-layered and has a carrier layer on which a transfer layer is applied by means of a release layer. The transfer layer may be a metallized layer or a glossy layer or a texture layer or a colored layer or a pattern containing one or more image patterns.

A foil supply roll 8th is the coating plant 2 preferably assigned to the side of the sheet feeder and has a rotary drive 7 on. On the downstream side of the printing unit is a film collecting roll 9 represented on which the used sheet material is wound and which also has a rotary drive 7 having. Furthermore, in connection with the rotary actuators 7 Means for maintaining a web tension of the transfer film 5 intended. A web guide for transfer films 5 with foil guide rollers 14 leads the transfer film 5 the transfer gap 6 to and from this way through openings in the coating plant 2 existing protection devices 15 ,

Furthermore, to stabilize the film web 5 a stabilization device between a first deflection roller and a first inlet roller to the coating unit 30 be arranged to flutter the film web 5 in widely strained web guiding areas.

The transfer process of the imaging example metallized layer on the sheet is carried out in the transfer nip 6 between the press roll 3 and the impression cylinder 4 ,

Likewise, a press roll 3 ' , as in 1 indicated in the order work 1 the transfer nip between blanket cylinder 13 and impression cylinder 4 downstream and the impression cylinder 4 be assigned. By means of the press roll 3 ' can a transfer film 5 ' on one on the printing cylinder 4 held sheet so that the imaging or metallization layer can be done there directly downstream of the imaging adhesive application.

The press roll 3 is with a press cover 10 For example, be provided as a plastic coating, comparable to a blanket or blanket. The Press covering 10 is held in a cylinder channel on jigs.

• a. Die Transferfolie 5 wird von der dem Auftragwerk 1 zugewandten Seite des Beschichtungswerkes 2 zum Transferspalt 6 geführt, etwa tangential zur Presswalze 3 durch den Transferspalt 6 und auf der gegenüber liegenden Seite abgeführt.
• b. Die Transferfolie 5 (strichliiert) wird von der dem Auftragwerk 1 abgewandten Seite des Beschichtungswerkes 2 zur Presswalze 3, um die Presswalze 3 herum durch den Transferspalt 6 und auf der gleichen Seite wieder abgeführt.
• c. Die Transferfolie 5' (strichliiert) wird im Auftragwerk 1 auf der der Bogenzufuhr abgewandten Seite des Druckwerkes einem Transferspalt 6' zwischen der Presswalze 3' und dem Druckzylinder 4 zugeführt und von dort wieder abgeführt, wobei der Transferspalt 6' einem dem Farb- bzw. Kleberdruck dienenden Druckspalt zwischen dem Drucktuchzylinder 13 und dem Druckzylinder 4 nachgeordnet ist.

In 1 three variants of the web guide are shown.

• a. The transfer foil 5 is from the the commission 1 facing side of the coating plant 2 to the transfer gap 6 guided, approximately tangential to the press roller 3 through the transfer gap 6 and dissipated on the opposite side.
• b. The transfer foil 5 (dashed) is from the the commission 1 opposite side of the coating plant 2 to the press roll 3 to the press roller 3 around through the transfer gap 6 and dissipated again on the same side.
• c. The transfer foil 5 ' (dashed) becomes in the order work 1 on the side facing away from the sheet supply of the printing unit a transfer nip 6 ' between the press roll 3 ' and the impression cylinder 4 supplied and discharged from there again, the transfer gap 6 ' a printing gap between the blanket cylinder serving for color or adhesive printing 13 and the impression cylinder 4 is subordinate.

In 1 is a main variant of an approximately tangential film guide between the press roll 3 and the impression cylinder 4 in relation to the press roll 3 or the wrap of the press roll 3 provided by less than 90 degrees. This should be a defined investment of the film web 5 on the press roller 3 achieves and at the same time the necessary conditions for a film timing or a film discontinuity in the transfer gap 6 during a channel pass, but also for the use of narrow film webs 5 be created.

The method relating to the film transfer is described in the Druckbzw. Application machine according to 1 as follows:
It is intended, at least in one the coating plant 2 following printing unit 50 apply a color print on the imagewise coated with a metallized layer sheet. Here, the sheet is from the coating plant 2 from the impression cylinder 4 via a sheet transfer drum or a sheet transfer unit to an impression cylinder 40 of the printing unit 50 transferred.

The printing unit 50 has as usual in offset printing the impression cylinder 40 , a rubber or blanket cylinder associated therewith 41 and a plate cylinder associated therewith 43 on. The plate cylinder 43 Here are shown schematically an inking unit and a dampening system assigned.

Between impression cylinder 40 and blanket cylinder 41 is another nip 60 educated. In this pressure gap 60 becomes printing ink from one on the plate cylinder 43 clamped pressure plate 44 out over one on the blanket cylinder 41 arranged cover 42 applied to the sheet.

To improve the adhesion of the transferred film parts in conjunction with a high-quality printing in the printing unit 50 The pressing is made depending on the type and elastic property of the blanket cylinder 41 arranged cover 42 and on the press roll 3 arranged press fabric 10 selected. On the one hand is on the press roller 3 preferably a hard-elastic and in its surface opposite the film web 5 less adhesive, but possibly very finely profiled cover selected.

On the other hand, on the blanket cylinder 41 a suitable for normal color printing cover as a blanket or blanket 42 chosen, which is designed to accept ink. The blanket or blanket can be made softer in terms of its elasticity, as in the press fabric 10 the press roll 3 is provided.

The pressing of the printing material in the transfer nip 6 or pressure gap 60 results from the fact that there is a distance adjustment for the function setting of the elements involved (ie for the film transfer or color printing) so that the gap is smaller by a certain amount than specified by the thickness of the substrate to be processed. Thus, the substrate is passing through the transfer nip 6 or the printing gap 60 compressed by the stringings (press clothing 10 and blanket 42 ) deform due to their elasticity by the amount used for the gap adjustment.

The settings in relation to the transfer gap 6 done by means of other control devices 46 that of the press roll 3 assigned.

The adjusting devices 45 . 46 are commonly used in offset printing on printing blanket or blanket cylinders of printing units or on cylinders of varnish modules.

In printing machines so-called machine controls are provided for controlling the processes. These machine controls contain all setting options for the printing unit 50 and also the printing units or application plants of the printing or application machine, in the coating plant 2 and the commissioned work 1 are included. This is also the setting of the gap of the Surfaces of the cylinders 3 . 4 respectively. 41 . 40 to each other with respect to the transfer nip 6 and the pressure nip 60 adjustable from there.

For this purpose, in conjunction with the machine control or separately, a control device may be provided which ensures the setting of the printing press on the cold foil transfer for corresponding settings in the printing units. The machine control of the printing press therefore provides that a special adjustment is provided for the cold foil transfer mode of operation.

Further applications of the method will become apparent in connection with the illustration 2 which is to be interpreted as meaning that the printing unit 50 Although shown as a paint module, functionally but also as a printing unit is to be evaluated. Therefore, a printing unit or several printing units could be used instead of the paint module shown.

An embodiment of a method according to the invention for avoiding reductions in cold foil transfer and overprinting of a coating is described below with reference to FIG 3 described

The object of this invention is now the risk of cleavage of film particles from one of the transfer film 5 To reduce or avoid transferred Foliensujet in subsequent printing units D in a overprinting of a previously transmitted to the sheet with foil printing image. The film material or the transfer layer, which is usually formed as a 1 to 2 my thick aluminum layer, is first of the carrier film of the transfer film 5 removed by the rapid adhesive paint on the substrate or the sheet. The structure of the aluminum layer is designed such that details and fine contours can be dissolved out. A possible subsequent overprinting, such as in a sheetfed offset press with offset printing ink, represents a splitting process for already existing layers on the substrate. Repeated development of the ink-conducting surfaces over a surface provided with the aluminum layer of the transfer layer often leads to retransfer with the formation of deposits of Metal pigments on the color-guiding blanket (splitting of the previously applied coating). Of these, especially the first color-printing unit is affected that on the coating 2 Folientransfervorrichtung follows. This process with a build-up of metal particles acting as an impurity in the printing ink in turn influences the print quality in the subsequent color printing, because due to the metal deposition on the blanket a disturbed ink transfer and / or color splitting occurs. Furthermore, the detached metal particles migrate or roam through the inking unit and can be deposited at other locations not intended for the transfer of metal layers.

By means of the method according to the invention described hereinbelow, it is possible to reduce or avoid the above-described reverse cleavage process of parts of the previously transferred metal layer.

The cold foil transfer device is usually installed in the first two printing units of a sheet-fed offset printing press. In this case, as described above, in a first printing unit as a commissioned work 1 by means of a planographic printing plate of a plate cylinder 12 over a rubber cylinder 13 the glue color or the glue on the on a impression cylinder 4 applied printed sheet applied. Thereafter, by means of a second as a coating plant 2 trained printing unit in a transfer nip 6 between a press roll 3 and an impression cylinder 4 a metallic transfer layer of a transfer film 5 as a film image transferred to the substrate or the sheet. The transfer foil 7 is doing of a film supply roll 8th through the transfer gap 6 to a foil collecting roll 9 guided.

In order to avoid the re-splitting process during printing in printing units D following the cold foil transfer device, it is provided in one between the units 1 . 2 for the film transfer and the printing units D for the color printing or other coating operations switched operation to provide the film layer on the substrate or the printed sheet with a protective layer, preferably a lacquer layer. This can be in an additional aggregate 20 be executed, which is preferably designed as a printing unit A or coating unit B. Likewise, special coating units in the form of an inline unit C can be provided on suitable work surfaces in the designated process area. For example, inkjet printheads can be used as the inline aggregate C.

Inkjet printheads are particularly advantageous when a space-saving design is preferred.

By means of this additional process step, the metallic transfer layer applied to the substrate or the printing sheet can be protected and at the same time a better bond can be produced between the metallic transfer layer and the substrate or the printed sheet

In this way, then no particles of the metallic transfer layer more out of the already applied transfer layer are dissolved out.

The step according to the invention of a coating or liquid application onto the metallic transfer layer still exposed on the printing sheet can take place via a printing unit A or via a coating unit B, which is additionally arranged inside the sheet-fed offset printing machine.

If the auxiliary unit 20 is designed as printing unit A, then there are next to a counter-pressure cylinder 4 a plate cylinder 43 and a rubber cylinder 41 intended. On the plate cylinder 43 becomes a printing plate 17 attached, which may correspond to a printing plate, as on the plate cylinder 12 the applicator 1 is appropriate.

If the auxiliary unit 20 is designed as a coating unit B, then there is next to a counter-pressure cylinder 4 a form cylinder 41 intended. On the form cylinder 41 becomes a printing plate 17 or a paint form attached, the subject of which may correspond to a printing plate, as on the plate cylinder 12 the applicator 1 is appropriate.

The protective layer or lacquer layer can furthermore be effected directly in a printing unit A or coating unit B in arrangement in the sheet transport direction behind the cold foil transfer device or by means of an inline aggregate C arranged for the protective coating application in the printing unit A or coating unit B. Possibly. Such an inline aggregate C can also be used as a coating unit 2 serving printing unit itself be arranged. Furthermore, the protective layer or paint application can also by means of a coating unit B, which is additionally arranged within the sheet-fed printing press and formed in the manner of a flexographic printing, take place.

In an embodiment variant which is advantageous according to the invention, the use of a printing plate is required for the protective coating application 17 provided, wherein the pressure plate 17 has the same Drucksujet as the printing form of the adhesive ink on the plate cylinder 12 , As a result, only paint or binder or primer is transferred where it is needed. All other parts of the printing form can be printed or painted in a conventional manner without any possible impairment by the paint or binder or primer.

To improve the adhesion of the film image, the protective layer can also be designed so that it overlaps the edges of the film image to the substrate and thus provides protection for the edges of the film image.

However, the effect of the protective layer is effective only when it is in a dried state. For this purpose, the use of a special dryer for drying or curing or the provision of a sufficiently long drying time for a sufficient Wegschlagen is required.

Drying is therefore required for efficient operation. Here a UV-curing lacquer or binder or primer offers the best conditions. The overprinting of the transfer layer from the process step of the cold foil transfer, which can thus be carried out in an ideal manner by means of a UV-active coating, can then be applied to a cured surface in the cold foil transfer and the auxiliary unit 20 following printing units D done in the inline printing process.

The use of inkjet printheads as inline aggregate C can be done at different locations.

According to 3 Inline Aggregates C can initially be used in conjunction with the coating plant 2 be attached. Then the coating process takes place directly after the film transfer on the same impression cylinder 4 and before the action of a dryer arranged thereafter 16 ,

Furthermore, an inline aggregate C also on the forme cylinder or blanket cylinder 43 of the additional unit 20 can be arranged so that a variable controllable protective layer transmission can be made via an intermediate medium.

• A) Inkjet-Druckkopf in Inline-Aggregat C am Gegendruckzylinder 4 des Beschichtungswerkes 2
• B) Druckwerk A in Anordnung in Bogenlaufrichtung R nach dem Beschichtungswerk 2 mit Druckplatte 17 am Plattenzylinder 43
• C) Lackierwerk B in Anordnung in Bogenlaufrichtung R nach dem Beschichtungswerk 2 mit Druckplatte / Lackform 17 am Formzylinder 41
• D) Inkjet-Druckkopf in Inline-Aggregat C am Gummizylinder 41 im Druckwerk A in Anordnung in Bogenlaufrichtung R nach dem Beschichtungswerk 2
• E) Inkjet-Druckkopf in Inline-Aggregat C am Formzylinder 41 im Lackierwerk B in Anordnung in Bogenlaufrichtung R nach dem Beschichtungswerk 2

Thus, there are preferably the following procedural and local variants for applying the protective layer:

• A) Inkjet print head in inline aggregate C on the impression cylinder 4 of the coating plant 2
• B) printing unit A in arrangement in the sheet running direction R after the coating plant 2 with pressure plate 17 at the plate cylinder 43
• C) coating unit B in arrangement in the sheet running direction R after the coating plant 2 with pressure plate / paint form 17 on the form cylinder 41
• D) Inkjet print head in inline aggregate C on the blanket cylinder 41 in the printing unit A in arrangement in the sheet running direction R after the coating plant 2
• E) Inkjet print head in inline aggregate C on the forme cylinder 41 in the coating unit B in arrangement in the sheet running direction R after the coating plant 2

Other configuration options are of course in the context of professional practice representable.

In a development of the invention, it is proposed that the printing ink and / or the varnish for the overprinting or coating of the transfer layer be subjected to a special evaluation. If the printing inks or varnishes by means of other printing units D or units are used to produce a full or partial coating of the sheet at the end of the machine, the varying documents on the sheet are taken into account.

It is first of all essential that in the selection of the lacquer or binder or primer used for the formation of the protective layer on the film image, their interaction with the metallic film layer is taken into account. Furthermore, the repercussions with regard to adhesion, gloss and color effect must be matched to the film material.

This can ensure that a conventional ink transfer or a conventional paint application and sufficient adhesion of the printing ink and the paint on the transfer layer of the transfer film at the end of the production process are ensured.

LIST OF REFERENCE NUMBERS

1

 commissioned

2

 coating plant

3

 press roll

3 '

 press roll

4

 Impression cylinder

5

 Transfer foil / foil web

5 '

 Transfer foil / foil web

6

 transfer nip

6 '

 transfer nip

7

 roller drive

8th

 Film supply roll

9

 Foil composite role

10

 Press covering

11

 inking

12

 plate cylinder

13

 rubber cylinder

14

 Folienleitwalze

15

 Printing plant security

16

 dryer

17

 Printing plate / printing form

18

 dancer roll

30

 stabilizing device

40

 Impression cylinder

41

 Blanket cylinder

42

 Blanket / blanket

43

 plate cylinder

44

 printing plate

45

 setting device

46

 setting device

47

 Underlay sheets

48

 mark

50

 printing unit

60

 nip

80

 control station

A

 printing unit

B

 Painting works

C

 Inline unit

D

 printing unit

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0569520 B1 [0002]

Claims (11)

Method for transferring a removable image-forming transfer layer from a transfer film ( 5 ) on printed sheets provided with an adhesive coating by means of a coating unit ( 2 ), which has a common transfer gap ( 6 ) forming impression cylinder ( 4 ) and a press roll ( 3 ), through which the transfer film ( 5 ) from a film supply roll ( 8th ) the press roll ( 3 ) is contactable, such that it with the transfer layer on the on the impression cylinder ( 4 ) guided print sheet lying on and under pressure for transferring the coating together with the sheet through the transfer nip ( 6 ) is carried out, a) wherein in the applicator ( 1 ) image-wise adhesive application to the printed sheet takes place, b) wherein in the transfer nip ( 6 ) under pressure a sujet of the transfer layer of the transfer film ( 5 c) wherein a protective layer is applied at least to the transfer layer thus applied to the printing sheet; d) after the protective layer has been applied drying the protective layer on the printed sheet; and e) after drying the protective layer of the printed sheet is overprinted pictorially with the inclusion of transfer layer and protective layer in partial or total area. A method according to claim 1, characterized in that the protective layer is dried after application and before overprinting or overcoating in other printing units (D) or coating units by means of a drying device. A method according to claim 1 or 2, characterized in that the protective layer consists of a UV-curing medium and is irradiated by means of a UV radiation radiating drying device. Method according to one or more of claims 1 to 3, characterized in that the protective layer is applied in a sheet-fed offset printing press by means of a following in the sheet transport direction on the device for cold foil transfer printing unit (A). Method according to one or more of claims 1 to 3, characterized in that the protective layer is applied in a sheet-fed offset printing press by means of a following in the sheet transport direction on the device for cold foil transfer coating unit (B). Method according to one or more of claims 1 to 3, characterized in that the protective layer is applied in a sheet-fed offset printing machine by means of an inline unit (C), which is assigned in the sheet transport direction (R) to the device for the cold foil transfer following a coating position. Method according to one or more of claims 1 to 6, characterized in that the protective layer by means of a pressure plate ( 17 ) or printing form is generated, whose subject corresponds to the printing plate, with which the adhesive on the plate cylinder ( 12 ) in the order ( 1 ) is applied. Method according to one or more of claims 6, characterized in that the protective layer is applied by means of one or more ink jet printing heads designed as inline aggregates (C). Method according to one or more of claims 1 to 8, characterized in that a lacquer or a binder or a primer is used as a medium for the production of the protective layer. A method according to claim 9, characterized in that the medium for producing the protective layer in its composition is matched to the metallic transfer layers such that a good adhesion of the protective layers is ensured on the transfer layer and that an optical change of the surface of the transfer layer with respect to coloring and / or gloss is made or avoided. A method according to claim 9 or 10, characterized in that the medium for the production of the protective layer is adjusted in its composition to the printing or varnishing used for further printing or varnishing of the printed sheets in the following on the cold foil transfer printing units (D) or coating units, that a good adhesion of the other layers is ensured on the protective layer.

Images