EP2296891A1

EP2296891A1 - Device for cold foil embossing

Info

Publication number: EP2296891A1
Application number: EP09761592A
Authority: EP
Inventors: Uwe Püschel; Guido Reschke; Jürgen Schölzig
Original assignee: Manroland AG
Current assignee: Manroland Sheetfed GmbH
Priority date: 2008-05-28
Filing date: 2009-05-25
Publication date: 2011-03-23
Anticipated expiration: 2029-05-25
Also published as: EP2296891B1; CN102046382B; WO2009150029A1; CN102046382A; JP2011522719A; DE102009026438A1

Abstract

The aim of the invention is to develop the foil guiding process in a coating unit (2) for transferring image-forming layers from a transfer foil to a medium to be printed. To achieve this, the coating unit is equipped with a restricted-area pressing plate for transferring layers from the transfer foil. This allows the targeted control of the foil feed. The transfer foil is preferably guided past a pressing roll (3) approximately tangentially to said roll and with a restricted width. Special delivery devices (22, 33), which can operate cyclically, are provided for storing and delivering the foil.

Description

manroland AG

Apparatus for cold foil stamping

The invention relates to a device for transferring imaging layers from a carrier foil to printed sheets according to the preamble of patent claim 1.

It is known to produce metallic layers on printed sheets by means of a film transfer process. Thus, EP 0 569 520 B1 describes a printing material and a printing device using this material. In this case, a sheet-processing machine is shown, which has a feeder and a boom, wherein printing units and a Beschichtungsmo- 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 confining module, wherein by means of the press roller, the pressure sheet resting on the counter-pressure cylinder is brought into contact with the sheet material. In this case, the downwardly lying metallic layer enters into a close connection with the areas provided with adhesive on the printed sheet.

25.05.2009 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.

The object of the invention is therefore to provide a device by means of which the transfer of an imaging 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. In particular, a partial film application is to be made possible.

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

The device provides a clock system for guiding the film web.

Advantageously, the device is characterized in that a press roller has a pressing surface which occupies a partial area of the total area of a printed sheet. Advantageously, such press surfaces are designed as tensionable segments or as cut-out rubber blankets or as passably produced, preferably photopolymer high-pressure plates or as detachable, for example under magnetic action, attachable pressing segments.

Different working materials can be used for this purpose. Can be used

- A so-called stripped rubber blanket with the printing surface removed to the effective area

25.05.2009 - A polymeric cutting plate, for example, from the plate production by means of a Flachbettplotters, possibly also with a substrate made of aluminum or polyester

a photopolymer plate e.g. from an exposure, if necessary with aluminum sheet / foil as carrier material.

- Can also be used a blanket, which is applied to a metal support; Such a blanket may optionally have a cushioning intermediate layer and be provided with a thin but hard and smooth cover layer.

As a substructure of the corresponding partial pressing fabric is provided, a pad with or without damping effect, e.g. to use a vacuum blanket.

As clamping systems arise a clamping spindle as in a blanket cylinder known or so-called combination clamping rails for blankets or printing plates, as known from the blanket cylinders or the form of cylinders. Depending on the structure, the surface of the press cylinder elevator is also suitable for profiled embossing.

This results in an extended range of applications for the process of cold foil stamping. The makeready shortening is achieved by prepared press cylinder lifts. In addition, register automation can be introduced.

As a solution, add the press cylinder to a register system, e.g. is executed via register pins. The press cylinder should be adjustable e.g. in the manner of a register system for automatic printing plate tension. The side and circumferential register can be adjustable as in a forme cylinder. In addition, the press cylinder elevator may be provided with register punches.

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

25.05.2009 The aforementioned methods can be used side by side so also different types of films.

To ensure the economic efficiency of the coating process, it may be provided to control the film advance such that the transfer film is stopped when there is no transfer of the imaging or metallization layer.

Advantageously, a control of the transfer film can be carried out such that, when passing through a cylinder channel receiving the grippers of the sheet-guiding impression cylinder, the film feed is stopped, wherein the press roll then passes in a sliding manner under the transfer film.

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 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, superimpose another adhesive pattern enclosing the first 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.

Showing:

25.05.2009 Figure 1 is a basic illustration of a printing machine with a

Film transfer device and

FIGS. 2 to 5 show the structure of a coating module according to the invention with a film transfer device and various variants for the cyclical film guidance

FIG. 1 shows parts of a sheet-fed rotary printing press which contains two printing units and is used for the following purposes:

- A sheet is first provided with a two-dimensional or imaging adhesive pattern (printing unit as commissioned work 1).

In the following printing unit, the printed sheet is fed together with a transfer film 5 under pressure through a transfer nip 6 (coating unit 2).

The applicator 1 may be a per se known offset printing unit with an inking unit 11, a plate cylinder 12 and a blanket cylinder 13. The blanket cylinder 13 cooperates with a counter-pressure cylinder 4.

The coating unit 2 can also be formed by an offset printing unit. The transfer nip 6 in the coating unit 2 is formed by a press roll 3 and an impression cylinder 4. The press roller 3 may correspond to the blanket cylinder. The press roll 3 can also correspond to the forme cylinder of a lacquer module. Within the used for the film transfer coating 2 a web guide 14 is shown for transfer films. The transfer film 5 is thereby switched on and executed by protective devices 15 of the coating unit 2.

The film supply roll 8 is assigned to the coating unit 2 on the side of the sheet feed. The film supply roll 8 has a rotary drive 7 for the continuous controlled feeding of the transfer film to the coating unit 2. In the film feeder deflection or tension rollers for guiding the

25.05.2009 Transfer film 5 may be provided in a substantially constant tension against the press roller 3. On the downstream side of the printing unit, a film collecting roller 9 is provided for the used sheet material. A rotary drive 7 on the film collecting roller 9 is always advantageous. It may even be provided that the transfer film 5 is conveyed on the outlet side by means of the rotary drive 7 and held taut on the supply side by means of a brake.

The press roll 3 (as a blanket cylinder or forme cylinder or separate press roll) carries on its surface a compressible or damping, e.g. also provided with a compressible intermediate layer element. For this purpose, the press roll 3 can be provided with a press fabric 10, for example as a plastic cover, comparable to a blanket or blanket, which is held in a cylinder channel on clamping devices.

To ensure the efficiency of the coating process can be provided, the film feed of the transfer film 5 from the film supply roll 8 to the transfer nip 6 and the film collection roller 9 is gradually controlled, the transfer film 5 is then stopped, if no transfer of imaging or covering layers should take place. The associated device preferably includes a corresponding feed control for the transfer sheet 5, which ensures that at least the lying in the region of the press roller 3 and the impression cylinder 4 part of the film web is stationary as long as the cylinder channel passes. For this purpose, details will be explained later in FIGS. 2 to 5.

A further improvement of the film utilization of the type described results when the transfer film 5 is divided into one or more Teilfolienbahnen lesser width. In this way, with appropriate control by means of the device or devices for timing the film advance, each of the partial film webs can be improved, and the utilization of the transfer film 5 can be improved even with zonally different coating regions within one sheet.

25.05.2009 Furthermore, dryer 16 can be provided in the film application module thus formed from the applicator 1 and the coating unit 2, by means of which the adhesive application or the entire film coating can be dried. Here, for example, UV dryers come into question.

Furthermore, the film application module may include a monitoring device 17 for scanning the sheet surface. The monitoring device 17 enables the evaluation of image contents of the coating and the detection of defects in the film coating. Such a monitoring device can also be provided in conjunction with the printing press, in which the film application module is integrated. Then it can be arranged for example in the sheet delivery of the printing press or a last printing unit.

The transport of the transfer film 5 can be monitored on or between film guide rollers 14 by checking the web tension of the film web 5. One or more web tension measuring devices 19 are provided for this purpose in a film web guide.

Furthermore, in order to stabilize the film web 5 between a first deflecting roller and a first inlet roller to the transfer unit, a stabilizing device 30 can be arranged in order to reduce flapping movements of the film web 5. The stabilizing device 30 has z. B. two rotatably mounted rollers, which is provided for the variable setting of the wrap angle of the film web 5 on the guide rollers, so that the guiding action and the damping effect on the film web 5 is adjustable depending on the operating state. The adjustment of the stabilization device 30 can be carried out in conjunction with means for web tension control 19 and possibly a sensor device 20 for web break monitoring.

Electrical signals of the web tension measuring devices are evaluated. Various operating states are possible for this:

1. A web train above a predetermined minimum value is evaluated as a signal for the presence of the film web 5 and fed to the machine control.

25.05.2009 2. Exceeding the maximum value of the predeterminable web train is reduced by means of dancer rollers 18 or roller drives 7 of the film supply 8 or collecting roller 9. Thus, impermissible web elongation or web break can be avoided.

3. If the minimum specified tension is undershot, it is checked whether the web tension control is still active. If it is not possible to increase the web tension by means of dancer rollers 18 or a brake, web break is detected.

The additionally obtained information about the web tension as the actual value, in particular in the context of the aforementioned evaluations, can be used for the control of the printing or transfer process. For this purpose, the system can be coupled to a control station of the printing machine, via which the setpoint values for maximum and minimum web tension can be entered. This may depend on the type of transfer film 5 used and on the printing or transfer conditions in the coating module 2 in connection with the properties of the printing substrate, the adhesive or the press cover.

The necessary data can be read via interfaces directly from data carriers to film supply rolls and changed by means of parameter values from the setting of the transfer process on the coating module 2.

The method relating to the film transfer is described in the Druckbzw. Application machine according to Figure 1 carried out as follows:

It is intended, at least in a printing unit 50 following the coating unit 2, to apply a color print to the printed image sheet coated with a metallized layer. In this case, the printed sheet from the coating unit 2 is transferred 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. The printing unit 50 has, as usual in offset printing units, the counter-pressure cylinder 40, an associated rubber or blanket cylinder 41 and a plate cylinder 43 associated therewith. The plate cylinder 43 are here shown schematically an inking unit and a dampening unit assigned.

25.05.2009 Between counter-pressure cylinder 40 and blanket cylinder 41, a further pressure gap 60 is formed. In this printing gap 60 ink is applied from a spanned on the plate cylinder 43 printing plate 44 via a arranged on the blanket cylinder 41 cover 42 on the sheet.

The gap of the printing gap 60 between the surfaces of the blanket cylinder 41 and the impression cylinder 40 is adjustable by means of the printing blanket cylinder 41 associated adjusting devices 45. In the field of offset printing, this is usually referred to as printing provision, since the aforementioned setting relates to the thickness of the printing material to be processed, which is to be printed in the printing nip 60. For this purpose, a printing pressure is necessary to transfer the ink from the blanket cylinder 41 to the held on the impression cylinder 40 substrate. The adjustments with respect to the transfer nip 6 are made by means of further adjusting devices 46, which are assigned to the press roller 3.

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

Furthermore, a kontuherte or segmented pressing surface in the press fabric 10 should be provided as the surface of the press roll 3. For this purpose, instead of a full-surface pressing area on one or more areas to be coated limited segmented pressing areas are used on the press roller 3. The segmented pressing surface may be formed as an isolated surface element, as an annular, narrow surface element encircling the press roll 3, as a surface line following a limited peripheral portion covering over the width of the press roll 3 reaching surface element or in the form of several such surface elements pronounced and so the press fabric 10 form. For this purpose, for example, a cut-out printing blanket, an imageable plastic high-pressure mold or a pressure pad which is preferably releasably affixed to a smooth base, possibly stickable or magnetically attachable, can be used to support the segmented pressing surface. One at its bottom with

25.05.2009 a magnetic adhesive surface provided Andrucksegment can be placed for example directly on the surface of the press roller 3. On the other hand, a magnetic film can be clamped onto the surface of the press roll 3, to which then a contact pressure segment with a magnetically adhering rear side can be placed for affixing or positioning the segmented press surface 10. The surface and the inner structure of the Andrucksegmentes should correspond to the information described above in terms of elasticity and smoothness. Here, a compressible pad may be provided which carries a preferably smooth relatively firm functional position.

The function of this limited segmented pressing surface in the press fabric 10 is that - similar to the passage of a cylinder channel of the press roll 3 and the opposite impression cylinder 4 - the entrapment of the transfer film 5 is given only if the segmented press surface the transfer film 5 touching the transfer nip. 6 passes. In other words, the pressing surface should only be able to act on the transfer film 5 in the areas where actually imaging layers are to be transferred from the transfer film 5 to the printing sheet.

Thus, two effects can be achieved in a coating module 2 with a segmented pressing surface provided in a press fabric 10:

I. First, to carry out a film timing, the transfer film 5 can be stopped in advance in a very advantageous manner in addition to the period of the channel passage, if the area to be coated is located somewhere within the image area of the sheet and has not yet reached the area of the segmented pressing surface, or the area of the segmented pressing surface ends before the end of the sheet area to be coated. The transfer film 5 therefore only has to be transported if the segmented pressing surface within the transfer nip 6 is between

Press roll 3 and impression cylinder 4 is engaged. Thus, the utilization of the transfer film 5 between the sheets to be coated can be almost complete.

25.05.2009 The film transport is stopped here when using an annular pressing surface only at the channel pass.

When using pressing surfaces in the form of single or multiple, cylinder-wide, over sub-segments reaching segments of the film feed can be lent additional loan while free surfaces on the circumference of the press roll 3.

II. 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 Teilfolienbahnen lesser width. This is particularly advantageous in connection with the segmented pressing surface. In a segmented

Pressing surface, the transfer sheet 5 can be used limited to the width of the pressing surface. The savings in film consumption is significant. The film guide in the transfer nip 6 is significantly improved by a full-surface support of a narrow web of the transfer film 5 on the segmented pressing surface, at least in the transfer nip 6.

In this way, with appropriate control by means of the device or devices for timing the film advance, each of the partial film webs can be improved, and the utilization of the transfer film 5 can be improved even with zonally different 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.

In combination with the above-mentioned method, it is thus also possible to use different types of film side by side. This allows surfaces of different film color or different smoothness or texture to be created.

For the construction of the partial press fabric, different working matehals known per se can be used. Can be used - stripped rubber blanket, where the rubber printing surface was removed except for the area to be embossed

25.05.2009 - Polymeric cutting plate (cliché for flexographic printing), which can be produced by means of a flatbed plotter and optionally equipped with a carrier made of aluminum or polyester

- A photopolymer plate (flexographic printing), the surface contour can be produced with exposure and washing out (possibly with aluminum support). - Can also be used a rubber blanket with a metal carrier that can be prepared and used like a stripped rubber or blanket.

As a substructure of the corresponding press fabric 10 with segmented press surfaces is a pad with or without damping effect, such as a vacuum cloth (but only in press clothing without rigid support layer) used.

Clamping systems in the cylinder channel of the press roll 3 for attaching the press fabric 10 may be tensioning spindles such as in a blanket cylinder or combination clamping rails for blankets or printing plates, as known from the rubber or the form cylinder. The surface of the press fabric 10 is suitable depending on the structure for profiled imprints. This results in an extended range of applications for the process of cold foil stamping. Using the above elements, a very simple and fast handling of the device of the film application module is possible.

According to the invention devices are provided which allow the cyclic promotion of the film web 5. Here, as operating variants from the previously executed

a channel timing in the passage of cylinder channels of the press roll 3 and the impression cylinder 4,

- A formattaktung limited to the format length of the film transfer on the circumference of the press roll 3 film feed and

- A Prägebereichstaktung when limiting the film guide to be defined by segmented pressing areas in the press fabric 10 of the press roll 3 defined film feed.

For the film supply (and the discharge) is usually the drive of the film rolls 8, 9 continuously provided, since the mass of the film rolls 8, 9 to

25.05.2009 great for a quick change of drive movement. This results in braking the film web to re-accelerating in the transfer area in the supply and discharge of the film web 5 relative to the movement of the film rolls 8, 9 excess or missing film lengths.

Therefore, solutions are proposed according to the invention, which can buffer the resulting in continuous Nachförderung or removal of the film web 5 excess or missing pieces of web. These are basically already described with the dancer rollers 18 as a variant of foil stores. However, the dancer rolls 10 are not sufficiently controllable on the described in the described high speed clocking in the film transfer process, especially since they are usually far away from the place of consumption and close to the film roll 8, 9 to maintain the web tension there. In FIGS. 2 to 5, further possibilities for rapid compensation of web displacements in film timing in the cold foil process are therefore specified.

FIG. 2 shows a film transfer module corresponding to FIG. Here, the dancer rollers 18 are arranged to regulate the web tension. To compensate for major changes in the film promotion, such as stopping the film promotion in the transfer area (range of film transfer between press roller 3 and impression cylinder 4) without film consumption (channel timing, format- clocking, timing on embossed areas), are additionally in front of the inlet of the fresh film web. 5 in the transfer nip 6 and after the exit of the used film web 5 from the transfer nip 6 designated as drive groups 22 Wai- zenpaare 23, 24 are arranged.

The drive groups 22 are described here for all subsequent embodiments and each show a pair of rollers that can pinch the film web 5 and thus defined in terms of a desired transport path can lead. The WaI- zenpaare the drive groups 22 consist in Figure 2 each consist of a foil guide roller 24 and a drive roller 23. Both the film guide roller 24 and the drive roller 23 is at least partially driven. The drive of the drive roller 23 can not only in the transport direction of the film web 5 (of film roll 8

25.05.2009 to 9), but may also generate return strokes. This makes sense, since the film web 5 does not stop immediately when decelerating and thus runs over a desired breakpoint. As a result, a piece of the film web 5 could not be used. A short defined return stroke after the braking and stopping of the film web 5 in the transfer region reduces or eliminates this unnecessary film consumption. For this purpose, the drive of the drive roller 23 can be controlled quickly. The drive roller 23 itself can be segmented in order to be able to execute the changing drive movements quickly. Furthermore, the film guide roller 24 with respect to the drive roller 23 can be pivoted up and down, but it can also be permanently employed on the drive roller 23.

Thus, it can also be provided that the film guide roller 24 perform a more or less controlled by the film web 5 movement, while the drive roller 23 performs a conveying movement and the return stroke movement. For a defined period of time, the film guide roller 24 carries out a reverse-rotating movement with respect to the film transport direction only by controlled setting against the film web 5 resting on the drive roller 23. The drive roller 23 then performs a continuous transport movement against the direction of the film web 5. This is possible because the film web 5 at this time point is freely movable in the transfer area due to the lack of contact pressure by the press roller 3 against the impression cylinder 4. , Furthermore, the drive groups 22 can also hold the film web 5 in the transfer area under the necessary tension by braking at the time of sheet breakage, in this case at least on the feed side to the transfer nip 6, thus immediately upon restart of the film transfer with pressing by the press roller 3 against the impression cylinder 4 good transfer quality is achieved again.

The system of the drive group 22 is also suitable for segmented film guide rollers 24 in format width drive rollers 23 both for the guidance of a full-width film web 5 as well as for the guidance of, possibly also distributed, arranged sub-film webs 5. For this purpose, the segments of the film guide roller 24 can be arranged correspondingly adjustable to the positions of the partial film webs 5 in the axial direction to the press roller 3.

25.05.2009 The drive group 22 can be simplified by designing the drive roller 23 with a rough or adhesive surface or as a suction roller. With a correspondingly large looping through the film web 5, sufficient adhesion for the secure guidance of the film web 5 on the drive roller 23 can then be achieved. Then it would be possible to dispense with a foil guide roller 24, even in segmented form. This is also harmless in terms of the format-width design of the drive roller 23. A drive roller 23 designed as a suction roller could then be designed in such a way that suction devices which can be switched as needed in segments corresponding to the respective film web widths to be processed are provided if required.

According to FIG. 2, therefore, the film timing in the transfer area is to be carried out by means of the drive groups 22 with respect to the film storage by means of the dancers 18.1, 18.2. The dancer 18.1 in the region of the feed roller 8 takes on in the transfer area stationary film web 5 under the action of the web tension sensor located there, the film piece, which is released by the clamping of the film web 5 by means of the drive group 22. At the same time, the dancer 18.2 releases a piece of film for the film winding, since then no film web 5 is conveyed after. With renewed onset of the film promotion after the end of the interruption of the film promotion in the transfer area, the sequence of film release and film storage runs on the dancers 18.2, 18.1 in each case vice versa.

FIG. 3 shows a simplified embodiment in a coating unit 2. Here, on the one hand, the dancers 18 are shown, which are to serve only the web tension control.

Furthermore, a drive group 22 is again provided in the region of the film feed to the transfer area with the transfer nip 6. On the outlet side from the transfer area, a pendulum-held foil guide roller 25 is shown. This film guide roller 25 can execute a compensating movement directed transversely to the course of the transport direction of the film web 5. The compensation movement is marked with a dashed representation. Thus, the path of the film web 5 is extended and shortened. If the drive group 22 thus the Fo-

25.05.2009 The web guide roller 25 can perform a compensating movement to shorten the web path and thus release a piece of film web in order to compensate this movement with respect to the removal movement. If the promotion of the film web to start again, the film guide roller 25 performs a movement to extend the path of the film web 5 down. Thus, the film web 5 is accelerated again or released in the acceleration by releasing the drive group 22 track piece can be compensated.

In Figures 4 and 5 variants of the storage effects in the film timing are shown, which use a per se known principle of looping of the film web by applying negative pressure film memory 26.1, 26.2, 27.1, 27.2,28.1 and 28.2 are each assigned to one side of the coating unit 2. The film stores 26.1, 27.1 and 28.1 are respectively associated with the feed side of the film web 5 to the transfer nip 6 and thus the feed roller 8. The film stores 26.2, 27.2 and 28.2 are each associated with the discharge side of the film web 5 away from the transfer nip 6.

Each film store 26.1, 26.2, 27.1, 27.2, 28.1 and 28.2 consists of a vacuum chamber into which a film loop 29 of the film web 5 is fed in and out again.

The effect of the film reservoirs 26.1, 26.2, 27.1, 27.2, 28.1 and 28.2 is as follows: By sucking air (for example by means of one or more fans) on the bottom side of the vacuum chambers, the film loop 29 is in each case provided with a force that adjusts itself according to the negative pressure Injected negative pressure chamber. This force does not outweigh the predetermined by the web tension control tensile force of the film web 5, since the film loops 29 would otherwise be firmly sucked in the vacuum chambers. The system is self-regulating insofar as the film loops 29 can freely oscillate in the chamber against the force of the negative pressure and thus receive or release each foil web pieces. Since the system of the film memory 26.1, 26.2, 27.1, 27.2, 28.1 and 28.2 is freely oscillating, more drive groups have to be provided here than in the previously described systems.

25.05.2009 To regulate the film web promotion, the formation of the size of the film loops 29 (36, see FIG. 6) can be used. For this purpose, a sensor system can be provided in each of the vacuum chambers, which is formed approximately on the basis of the Abstandsmessung by means of ultrasound. This sensor detects how far the film loop 29, 36 is formed or how far the film loop 29, 36 is drawn into the vacuum chamber. On the basis of these constantly measured signals can then be regulated by means of the drives of the film rolls 7, 8 and possibly in conjunction with dancer rolls the film web conveying.

The two-sided arrangement of the film stores 26.1, 26.2, 27.1, 27.2, 28.1 and 28.2 (also 32.1, 32.2 in FIG. 6) serves to ensure that the timing of the film web feed can be carried out as follows when the film transport is stopped and continued in the transfer area: a) To stop film transfers and thus also the film transport in the

Transfer area (transfer nip 6) is by stopping the drive group 22 in front of the transfer nip 6 with running film roll 7 a running film web length free and pulled into the first film memory 26.1, 27.1, 28.1 or 32.1. b) On the discharge side after the transfer area, the film web 5 is simultaneously released from the second film store 26.2, 27.2, 28.2 or 32.2 for continuous winding. c) To continue the film transfer and thus the reinsertion of the film transport in the transfer area, the drive group is reactivated and the retracted film loop 29 from the first film store

26.1, 27.1, 28.1 or 32.1 returned to the transfer area. d) At the same time, the second film store 26.2, 27.2, 28.2 or 32.2 is again filled with a film loop 29, 36.

According to Figure 4, two variants for the arrangement of foil stores 26.1, 26.2, 27.1 and 27.2 are shown.

At the bottom of the film transfer module of the coating unit 2 small film storage 26.1 and 26.2 are shown. These are with the drive groups 22nd

25.05.2009 the transfer area at the transfer nip 6 combined. In addition, the film stores 26.1, 26.2 each foil guide rollers 14 are assigned to guide the film web 5.

At the top of the film transfer module of the coating unit 2, larger film stores 27.1 and 27.2 are shown. These are combined with their own drive groups and possibly with drive groups 22 of the transfer area at the transfer gap 6. In addition, the film stores 27.1, 27.2 are each associated with film guide rollers 14 for guiding the film web 5. The foil stores 27.1, 27.2 associated drive groups 22 are used to hold the film web 5 when the negative pressure at the film stores 27.1, 27.2 collapses or other disturbances occur in the film promotion. In addition, with these drive groups 22, a further control option for the railway conveying.

The system of film stores 26.1, 26.2 is smaller in size, so that it is easier to integrate and responsive because of its small volume. With this system, so smaller fluctuations in the film web promotion can be compensated quickly and effectively and also serves the same timing. The system of film stores 27.1, 27.2 is built larger, thus receptive and can compensate for larger fluctuations in the film web promotion. This is suitable for a clocking that has to overcome large clearances during film transfer, ie if only short areas on film 5 are to be transferred at the circumference of the press roll.

FIG. 5 shows a variant with foil stores 28.1 and 28.2 in a coating unit 2 which allows even larger stores. The film stores 28.1, 28.2 are placed vertically and assigned directly to the drive groups 22 of the transfer area at the transfer nip 6. As a result of the vertical arrangement, the feed of the film web 5 from the film loop 29 in the film store 28.1 can be fed to the transfer area directly and without a film guide device of the first drive group 22 on the feed side. Likewise, the film web 5 on the discharge side of the transfer region without film guide elements on the film storage 28.2 whose film loop 29 are fed. In FIG. 5, two foil guide rollers 14 for discharging out of the housing of the coating

25.05.2009 work 2 shown. On the feed side of the film storage 28.1 and the discharge side of the film storage 28.2 roller pairs 14 are shown, which serve as pinch rollers for better guidance of the film web 5. The one film roll can, in turn, be designed as a drive roller 24 in order to be able to control the film web conveyance here as well.

In FIG. 6, according to the previously described functionalities, a further variant with foil stores 32.1 and 32.2 in a coating unit 2 is shown, which has a compact structure and permits larger stores. The film memory 32.1 is arranged approximately horizontally downstream under the film roll 7 and the film memory 32.2 is placed approximately perpendicular to the opposite side. The drive group 33 with two film guide rollers 35 and a drive roller 34 on the inlet side of the transfer area is assigned close to the transfer nip 6. The drive group 33 with a film guide roller 35 and a drive roller 34 on the discharge side from the transfer nip 6 is assigned to the film store 32.2. As a result of the horizontal arrangement, the feed of the film web 5 from the film loop 36 in the film store 32.1 can be arranged compactly and fed via a smoothing and stabilizing device 30 to the first drive group 33 on the feed side to the transfer area (transfer nip 6). For feeding and removing the film web 5 to and from the film storage 32.1 Folienleitwalzen 31 are provided to keep the film web 5 easily movable.

Furthermore, the film web 5 on the discharge side of the transfer region after the transfer nip 6 on the film web 5 smooth holding foil guiding elements 14 (in the manner of a smoothing and stabilizing device) are performed. These film guiding elements 14 also guide the film web 5 out of the area of the printing unit protection 15 on the coating unit 2. On the discharge side after the transfer region to the film storage 32.2 can also be arranged a drive group 37, which has a film guide roller 38 and a drive roller 39. To form a film loop 36 in the film storage 32.2, the film web 5 is fed without additional guide. The removal of the film web 5 from the film storage 32.2 via a film guide roller 31st

25.05.2009 On the feed side and the discharge side of the film storage 32.1 and on the discharge side of the film storage 32.2 a film guide roller 31 is shown, which serve to better guide the film web 5, so that the film web the film storage 32.1 exactly fed and kept smooth from the film storage 32.2 for winding is dissipated.

Alternatively, the drive group 37 for the discharge side of the film web 5 may be arranged on the film guide roller 31 on the film storage 32.2. For this purpose, because of the large wrap the film guide roller 31 itself be driven or it can also be assigned to this a further drive roller.

The drive groups 22, as well as the film guide roller 25 of Figure 3, may also be combined with suction rollers. Then the clamping of the film web is not so critical. The control of the suction air to such suction rolls but is run at a very high clock frequency.

The vacuum chambers of the film stores 26.1, 26.2, 27.1, 27.2, 28.1, 28.2, 32.1 and 32.2 can be designed according to the leading to film or partial film webs. If the vacuum chambers have the width of a film web and are displaceable, it is possible to respond flexibly to desired coating conditions.

Furthermore, separating devices which cover the lateral position of the film web 5 or partial film webs can be arranged in the work area overlapping vacuum chambers. Thus, the film storage 26.1, 26.2, 27.1, 27.2, 28.1, 28.2, 32.1 and 32.2 can be advantageously divided into a plurality of parallel vacuum chambers. If separating devices can be inserted into the vacuum chambers and / or are displaceable in the vacuum chambers transversely to the running direction of the film or partial film webs 5, it is thus possible to provide width-adjustable and separate vacuum chambers. These can be tuned to individual film webs 5 of different widths or to film webs of the same or different widths. Thus, the formation of film loops 29, 36 is improved and tailored to each leading to foil or Teilfolienbahnen.

25.05.2009 When covering individual, not occupied by a film web 5 chambers of the air consumption of the vacuum device can be minimized and better regulated.

It has been shown that the suction at the vacuum chambers of the film stores 26.1, 27.1, 28.1, 32.1 on the supply side to the transfer area can also serve to clean the film webs. In particular, particles which adhere to the web edge (mica, dust, contamination) are sucked into the vacuum chambers and removed via the suction devices. Therefore, it is advantageous if at least one filter device is provided in the vacuum supply of the vacuum chambers, which serves to separate the contaminants. Thus, simultaneously with the storage of film loops 29, 36, a cleaning of the film web can also be carried out, so that the transfer process proceeds without interruption and the coating unit 2 is kept clean.

The arrangement of the film storage 26.1, 26.2, 27.1, 27.2, 28.1, 28.2, 32.1 and 32.2 and the drive groups 22, 33 may be formed so that they are interchangeable in existing film transfer devices against dancer. Thus, a more efficient film guide for existing systems can be retrofitted in a simple manner.

The film guide can also be interrupted when the press roller 3 has an only partially occupied pressing surface, so that the film web can be stopped during the passage of not occupied with a pressing surface areas in the transfer nip 6.

The film supply and removal can be performed with controllable or self-regulating systems such as friction shafts and individual drives on the film rolls 8, 9 in the variants of a format-wide film roll or with multiple sub-film rolls.

25.05.2009 LIST OF REFERENCE NUMBERS

1 applicator

2 coating module

3 press roll

4 impression cylinders

5 transfer foil / foil web

6 transfer gap

7 roller drive

8 foil supply roll

9 foil collecting roll

10 press clothing

11 inking / dampening unit

12 plate cylinders

13 blanket / blanket cylinder

14 film guide

15 print protection

16 dryers

17 Inspection device / monitoring system

18 dancer roller

19 web tension monitoring

20 web tear monitoring

21 pressure cylinder blowing device

22 cylinder channel

22 drive group

23 foil guide roller

24 drive roller

25 film guide roller

26.1 Foil storage

26.2 Foil storage

27.1 Foil storage

27.2 Foil storage

28.1 Foil storage

28.2 Foil storage

25.05.2009 29 loop / film loop

30 stabilization device

31 film guide roller

32.1 Foil memory

32.2 Foil storage

33 drive group

34 drive roller

35 film guide roller

36 loop / film loop

37 drive group

38 foil guide roller

39 drive roller

40 impression cylinders

41 blanket cylinder

42 blanket / blanket

43 plate cylinder

44 pressure plate

45 adjusting device

46 adjusting device

50 printing unit

60 pressure gap

25.05.2009

Claims

Patent claims

1. Device for transferring imaging layers from a carrier film to printed sheets with at least one applicator (1) for an image-wise coating of the printed sheets with an adhesive and with a coating module (2) for transferring the imaging layers from the carrier film to the printed sheet a transfer gap (6) between an impression cylinder (4) and a press roller (3), whereby the carrier film with the coated side in contact with the printed sheet can be guided through the transfer gap (6) together with the latter and the imaging layers are image-wise onto the printed sheet are transferable, and with a device for feeding the transfer film (5) to the coating plant (2) and for removing it from the coating plant (2) with a drive for moving the transfer film in the working direction, the film feed of the transfer film (5) being carried out by means of a device for film guidance can be controlled in such a way that the transport of the transfer film (5) is stopped when no transfer of an imaging layer to a printed sheet takes place in the transfer gap (6) of the coating unit (2), characterized in that a control in conjunction with a film guide the transfer film

(5) is provided in such a way that when a gripper of the sheet-carrying counter-pressure cylinder (4) passes through the cylinder channel (22) of the press roller (3), the film feed is stopped, the press roller (3) sliding through while still touching the transfer film (5). and/or that a press covering (10) with a raised, contoured pressing surface is provided as the surface of the press cylinder (3), the pressing surface being limited to the maximum area to be coated and that when passing through an area of the press roller (3) outside the The film feed is stopped on the pressing surface limited to the area to be coated, with the press roller (3) sliding through while still touching the transfer film (5).

May 25, 2009

2. Device according to claim 1, characterized in that the transfer film (5) is divided into one or more partial film webs of smaller width and that the partial film webs are positioned or fed next to one another to the transfer gap (6), the partial film webs being the same or different from each other different imaging layers are provided and layers of different colors and/or different gloss and/or different surface structures can be produced.

3. Device according to claim 1 to 2, characterized in that the film web (5) is assigned controllable conveying devices for braking and accelerating in time with the processing of the film transfer.

4. Device according to claim 1 to 3, characterized in that the conveying devices (22, 33) are designed as pairs of rollers, the pairs of rollers guiding the film web (5) in a clamping manner and being drivable.

5. Device according to claims 3 to 4, characterized in that the conveying devices (22, 33) are assigned to a transfer area in front of the transfer gap (6) or in each case before and after the transfer gap (6) and that the conveying devices have film storage (26.1, 26.2, 27.1, 27.2, 28.1, 28.2, 32.1, 32.2) are assigned.

6. Device according to claims 1 to 6, characterized in that the film storage (26.1, 26.2, 27.1, 27.2, 28.1, 28.2, 32.1, 32.2) are designed as vacuum chambers each receiving at least one film loop (29, 36) of the film web (5). are.

7. Device according to claims 2 to 6, characterized in that the film storage (26.1, 26.2, 27.1, 27.2, 28.1, 28.2, 32.1, 32.2) as one or more film loops (29, 36) of a film web (5) or several partial film webs receiving vacuum chambers are formed, the vacuum chambers having one or more separating devices for limiting

May 25, 2009 have negative pressure areas in the width of one or more films or partial film webs.

8. Device according to claim 6 to 8, characterized in that the vacuum chambers have suction devices for generating a negative pressure, with one or more of the suction devices being able to suck off adhesions from the film web or webs (5) and that the suction devices are assigned filter devices for separating the adhesions are.

9. A method for coating printed sheets in a sheet-processing machine, in particular a sheet-fed rotary printing machine, using a transfer film (5) formed from imaging layers and a carrier film for transferring imaging layers from the carrier film to the printed sheets, thereby,

- that an image-wise coating of a printed sheet with an adhesive is carried out at least with an applicator (1), and

- that the imaging layers are transferred from the carrier film to the printed sheet by means of a coating module (2), with an impression cylinder (4) and a press roller (3) in the coating module (2) forming a common transfer gap (6) through which the transfer film ( 5) can be guided under pressure in such a way that it is placed with the coated side on the printed sheet guided on the impression cylinder (4), - the imaging layer Aen after the printed sheet emerges from the transfer gap (6) in the area of the image-forming layer provided with adhesive Areas of surfaces adhere conformally to the printed sheet and are lifted off the carrier film, the transfer film (5) being pressed against the printed sheet in the transfer gap (6) at least in the area of the image-like coating(s) and - that the transfer film (5) only then passes through the transfer gap (6) is conveyed when contact is made between the surface of the press roller (3) and the printing material resting on the counter-pressure cylinder (4).

May 25, 2009

10. The method according to claim 9, characterized in that one or more pressure segments are attached to the press roller (3), which have a pressing surface, the surface of which is adapted to the surface extent of the image-like coatings, and that the transfer film (5) is axial to the Press roller (3), seen, is fed to the transfer gap (6) only in the area of axle sections provided with pressing surfaces.

11. The method according to claim 9 or 10, characterized in that one or more pressure segments are attached to the press roller (3), the pressing surface of which is adapted to the surface extent of the image-like coatings, and that transfer film (5) in the circumferential direction of the press roller (3), seen, is fed to the transfer gap (6) only in the area of peripheral sections provided with pressing surfaces.

12. The method according to claim 9 to 11, characterized in that the transfer film (5) is fed to the transfer gap (6) step by step in the axial sections in which there is an occupation with pressing surfaces (21).

13. The method according to claim 9 to 12, characterized in that the transfer film (5) can be stored in a film storage before being fed to the transfer gap (6) during gradual feeding during a step in which no film conveying takes place and that the transfer film (5) after removal from the transfer gap (6) can be removed from a film storage during step-by-step feeding during a step in which no film is conveyed.

May 25, 2009

14. The method according to claim 13, characterized in that the transfer film / webs (5) is guided before and after the transfer gap (6) under the effect of negative pressure in film storage with negative pressure chambers forming film loops.

15. The method according to claim 14, characterized in that the transfer film (5) is cleaned in the film storage by means of suction devices in the vacuum chambers.

May 25, 2009