EP3013586A1

EP3013586A1 - Format-related cold-foil stamping

Info

Publication number: EP3013586A1
Application number: EP14736686.8A
Authority: EP
Inventors: Jürgen Schölzig; Uwe Püschel
Original assignee: Manroland Sheetfed GmbH
Current assignee: Manroland Sheetfed GmbH
Priority date: 2013-06-28
Filing date: 2014-06-27
Publication date: 2016-05-04
Anticipated expiration: 2034-06-27
Also published as: DE102014108718A1; EP3013586B1; WO2014207175A1

Abstract

The aim of the invention is to diversify foil feed in a coating station for transferring imaging layers from a transfer foil onto a printing material. For this purpose, a delimited pressing surface is arranged in the coating station for transferring layers from the transfer foil 5. This allows a targeted control of foil feed. The transfer foil 5 is guided past a press roll 3 preferably with a limited foil width and approximately tangentially. To delimit pressing surfaces, format supports 30, 31, 32 are provided for the press roll cover 10. The drives for moving the foil web 5 are controlled during timing depending on the respective thickness of the printing material.

Description

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. A sheet-fed machine has a feeder, a boom and between both units printing units and a coating module. 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, wherein by means of the pressure roller of the resting on the counter-pressure cylinder sheet is brought into contact with the film material. In this case, the downwardly lying metallic layer enters into a close connection with the areas provided with adhesive on the printed sheet. After removal of 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.

From DE 10 2009 026 438 A1 a device for cold foil stamping is known. In this device, the film feed in a coating module for the transfer of imaging layers from a transfer film to a printing material is to be extended in its applicability. For this purpose, a limited pressing surface is arranged in the coating module for transferring layers from the transfer film. For a targeted control of the film feed is possible. In this case, the transfer film is preferably guided past a press roll in a limited width and approximately tangentially. For foil storage and film conveying special cyclically operable conveyors are assigned for this purpose. The timing of the sheet feeding may be performed with respect to a circumferential break of cylinder knitting surfaces or with respect to the transfer sheet variable transfer zones variable on the circumference or across the width of cylinder knitting surfaces.

From DE 10 2009 002 254 A1 a film guide in an embossing device is known. It describes that in a coating module for the transfer of imaging or covering layers from a transfer film to a printing material, a flexible mode of operation for the production of complex substrates with gentle film treatment is to be used. For this purpose, a film application module is provided in a sheet-fed rotary printing press with means for regulating the web tension of the film web. It is provided that the drives of the film rolls are each provided with variable parameter sets for different operating conditions in order to keep the web tension of the transfer film at an optimum level for the film transfer. It has been found during tests that the unwinding of the press roll in relation to the surface of the substrate resting on the impression cylinder has a considerable influence on the application quality. The film is passed through a nip and now has to adapt to a rolling process of press roll and counterpressure cylinder. Although this can be approximately compensated by the known measures for influencing web tension conditions at the inlet and outlet of the film web to the transfer nip, but the transfer film follows by adhesion to the adhesive resting on the substrate rather the printing cylinder speed than a dancer roller.

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 are not flexible and develop when changing substrates a different pressure characteristics.

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 simple adaptation of the print quality to a wide variety of printing materials is to be made possible.

The solution of this problem arises according to the invention in a device having the features of claim 1.

A device for supplying transfer film to a coating module and for discharging from the coating module are associated with one or more conveyors, wherein the film feed is controllable by means of a control of the or all conveyors so that the transport of the transfer film can be stopped, interrupted or started. When passing through a portion of the press roll outside of limited by formatting edges or format pads on the area to be coated pressing surface is doing the Film feed stopped and the press roller running under further contact of the transfer film by sliding.

According to the invention, the controller has a data memory which is provided with parameter data for the drive control of the conveying devices. Depending on production parameters in the cold foil transfer, mutually assigned sets, pairs or group pairs of drive parameters are selected from the data memory and then fed separately to each conveyor. Advantageously, controllable conveying devices for braking and accelerating the film web are arranged in time with the processing of the cold foil transfer. The conveyors can be designed as pairs of rollers with at least one motor-driven drive roller and lead the film web by clamping. Advantageously, the conveying devices are driven such that the web tension of the film web is changed in the region between the conveying devices as a function of the feeding of the parameter sets.

Furthermore, the controller is advantageously set up in conjunction with a machine controller of the sheet-processing machine, so that upon input of specific substrate thickness data on the machine control unit, drive parameters assigned to this data are selected from the data memory and forwarded to the respective drives.

The selection can be made advantageously also on the basis of quality data of the coated sheet.

Furthermore, a combination of the selection of drive parameters for the driving of the film web can take place by first making an adjustment based on the printing material thickness, if necessary automatically, and then additionally using manual adjustment of the parameter setting for the quality parameters determined from the coating process Drives of the transfer film takes place. In the following the invention is illustrated in more detail with reference to figures. 1 shows a basic illustration of a printing press with a film transfer device,

2 shows the structure of a coating module with a film transfer device and

Figures 3 and 4, the arrangement of a press fabric on a press roll.

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

- A printed sheet is first provided with a two-dimensional or image-forming adhesive pattern (printing unit as commissioning unit 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 module 2).

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

The coating module 2 can also be formed by an offset printing unit. The transfer nip 6 in the coating module 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 may also correspond to the forme cylinder of a paint module. Within the coating module 2 used for the film transfer, a film guiding device 14 for transfer films is shown. provides. The transfer film 5 is thereby switched on and executed by protective devices 15 of the coating module 2.

The film supply roll 8 is assigned to the coating module 2 on the side of the sheet feed. The film supply roll 8 has a roller drive 7 for the continuous controlled feeding of the transfer film to the coating module 2. In the film feed deflection or tension rollers for guiding the 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 roller drive 7 on the film collection roller 9 is always advantageous. It can even be provided that the transfer film 5 is conveyed on the outlet side by means of the roller 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 cover 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 contains a corresponding feed control for the transfer film 5, which ensures that at least the part of the film web lying in the region of the press roller 3 and the counterpressure cylinder 4 is stationary as long as the cylinder channel 26 of the impression cylinder 4 passes through. For this purpose, details will be explained later in FIGS. 2 to 4. 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. Thus, with appropriate control by means of the device or devices for timing the film feed, each of the partial film webs, the utilization of the transfer film 5 can be improved even with zonally different coating regions within an arc.

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

A monitoring device 17 for the film application module enables the evaluation of image contents of the coating and the detection of defects in the film coating.

The transport of the transfer film 5 can be monitored on film guide devices 14 like some film guide rollers by means of web tension measuring devices 19. 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 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.

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 process. coating module 2 in connection with the properties of the printing material, 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 as follows: It is provided, at least in a printing module 50 following the coating module 2 to apply a color print on the imagewise coated with a metallized layer sheet. In this case, the printed sheet from the coating module 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.

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 blanket 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.

The adjustments with respect to the transfer nip 6 are made by means of further actuators 46 associated with the press roll 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 contoured 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 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 pressing 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.

For the construction of the partial press fabric, different working materials known per se can be used. Can be used

- For the blanket / the press fabric of the press roll suitable so-called underlay sheets or even format sheets, which extend only to the effective area for the film transfer

- Underlay sheet / size sheet, which are clamped together with the blanket / with the press fabric on the press roll

- Underlay sheet / format sheet, each of which can be tensioned on its own and locked under the blanket / press cover to the press roll

- On the press roll stick-on backing segments positioned in the active area on the surface of the press roll and spanned by the blanket There are devices for cyclically conveying the film web 5 are provided. Here, as operating variants from the previously stated facts a channel timing in the passage of cylinder channels of the press roll 3 and the impression cylinder 4,

- a formattaktung or a sujettaktung, on the coating or

Application length is related, 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 defined by segmented pressing areas in the press fabric 10 of the press roll 3 film feed

be cited.

For the film feed (also the discharge) usually the drive of the film rolls 8, 9 is provided continuously, since the mass of the film rolls 8, 9 is too large for a quick change of the drive movement. As a result, when the film web is slowed down until it accelerates again in the transfer area in the feed and discharge areas of the film web 5, excess or missing film lengths are produced compared with the movement of the film rolls 8, 9. Such transitional areas between film start and format or application start are also different in size with respect to each used format documents, as will be explained later in connection with Figure 5.

Therefore, solutions are proposed that can buffer the incurred in continuous Nachförderung or removal of the film web 5 excess or missing pieces of web.

FIG. 2 shows a possibility for rapid compensation of web displacements in the film timing in the cold foil process. A film transfer module according to FIG. 1 is shown. Here, the dancer rollers 18 are arranged to regulate the web tension and compensate for the changing film feed in the film timing.

To accomplish the movement changes in the film promotion, such as stopping the film promotion in the transfer area (area of film transfer between press roller 3 and impression cylinder 4) without film consumption (channel timing, formattaktung, timing over embossed areas), are before the inlet the unused film web 5 in the transfer nip 6 and after the exit of the used film web 5 from the transfer nip 6 as drive groups 22, 33 designated roller pairs of a drive roller 23 and a film guide roller 24 is arranged.

A first drive group 22 is arranged on the supply side of the coating module 2 in the direction of film transport in front of the transfer nip 6. It works with a first dancer system 18.1 on the inlet side of the transfer film 5 to the transfer nip 6 together.

A second drive group 33 is arranged on the outlet side of the coating module 2 in the direction of film transport after the transfer nip 6. This works with a second dancer system 18.2 on the outlet side of the transfer film 5 from the transfer nip 6 together.

The dancer systems 18.1, 18.2 are shown symbolically in FIG. 2 and can be designed according to different technical principles as dancer rolls, roll stands or even vacuum loop stores. In any case, however, they form a film store, which makes it possible to compensate for the excess or missing lengths of film which are produced with respect to the film rolls 8, 9, when a continuous advance of the film web 5 in the transfer nip 6 takes place with continuously running film rolls 8, 9. Therefore, the dancer systems 18.1, 18.2 are later even more generally referred to in their effect as a film storage as a supply memory 18.1 and acceptance memory 18.2.

The drive groups 22, 33 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 pairs of rollers of the drive groups 22, 33 consist in Figure 2 of a respective film 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 be directed not only in the transport direction of the film web 5 (from film roll 8 to 9), but can also generate return strokes. This is useful because the film web 5 are not immediately at a deceleration remains and thus runs over a desired breakpoint. As a result, a piece of the film web 5 could not be used. If a short defined return stroke is performed after the braking and stopping of the film web 5 in the transfer region, this step 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. The film guide roller 24 carries out a reverse rotation movement for a defined period of time with respect to the film transport direction only by controlled adjustment 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 is freely movable in the transfer area at this time due to lack of contact pressure by the press roller 3 against the counter-pressure cylinder 4. ,

Furthermore, the drive groups 22, 33 can also hold the film web 5 under the necessary tension in the transfer area by braking at the time of sheet breakage, in this case at least on the feed side to the transfer nip 6, so that when the film transfer begins again with pressing by the press roller 3 the impression cylinder 4 immediately good transfer quality is achieved again.

The system of the drive group 22, 33 is also in the case of segmented arranged film guide rollers 24 in format width drive rollers 23 both for the guidance of a full-width film web 5 and for the leadership of one or more, possibly also distributed, designed as narrow webs film webs. 5 suitable. For this purpose, the segments of the film guide roll 24 accordingly adjustable to the positions of the narrow film webs 5 in the axial direction to the press roller 3 may be arranged.

The drive group 22, 33 can be varied in that the drive roller 23 is executed with a rough or adhesive surface or as a suction roll or with a pneumatically acting non-contact pressing segment. With sufficiently large wrap, sufficient adhesion for secure guidance of the film web 5 on the drive roller 23 can be achieved. The dancer arrangement for compensating the conveying paths of the film web 5 during the timing of the feed can also be designed in the form of loop guides operated by means of negative pressure for the film web 5.

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.

Furthermore, it is provided that the film web 5 is guided in the region of the transfer gap 6 in a teilumschlingenden or approximately tangential path on the press roller 3 (see Fig. 4, film sections 5.1 and 5.2). For this purpose, a film section 5.1 in the region of the film inlet into the transfer nip 6 is guided by the film guide roller 14 at a corresponding angle with respect to a tangent through the transfer nip 6 into it.

Furthermore, a film section 5.2 in the region of the film outlet from the transfer nip 6 from a further film guide roller or the outlet side drive roller 23 at an appropriate angle with respect to a tangent through the transfer nip 6 out of this out.

By forming the angle between the film sections 5.1 and 5.2 or the respective angle between the film sections 5.1 and 5.2 and a tangent (see tangent line T in Figure 4) through the transfer gap 6 on the one hand ensures that the gripper on the impression cylinder 4 during the passage of Cylinder channels 26 can not push into the film web 5 and damage them. This concerns, in particular, the outlet side of the film web 5 at the transfer nip 6, since there the so-called gripper backs project slightly into the region of the cylinder channel 27 of the press roller 3 and can press against the freely stretched film web 5.

Furthermore, the angle between the film sections 5.1 and 5.2 but also chosen so that the film web 5 touches the surface of the press roller 3 only in a very narrow range. Ideally, this should be only a contact strip of a few mm in length on the circumference of the press roll 3 over the entire width of the press roll 3. The formation of the narrow contact strip ensures that the timing of the movement of the film web 5 at the moment of release or pressure reduction on the transfer film 5 in the transfer nip 6 can be done quickly by the transfer film 5 can be stopped as soon as possible. The same applies when the conveying movement begins again at the next beginning of a new transfer area (ie at the beginning of a press nozzle or at one end of the cylinder channel).

The arrangement of the extent of the film sections 5.1 and 5.2 in relation to a tangent T through the press nip 6 is shown schematically in FIG.

The film sections 5.1, 5.2 can be guided in mutually different guide angles relative to the tangent 4 and can thereby define a larger or smaller loop of the film web 5 on the press roller 3.

In Figure 3, the press fabric 10 for the press roller 3 is shown in a planar view. It shows the work areas for a planned film transfer. The working direction with respect to the direction of rotation of the press roll 3 is shown at the top by a directional arrow. The workspaces are marked by three format pads 30, 31, 32, which are the left margin

(Beginning of printing) connect the press fabric 10 and end against the working direction at the form edges K1, K2, K3. The format documents 30, 31, 32 are adapted to a width corresponding to the required working areas and with the respectively desired length of the working format in the Work area arranged format edges K1, K2, K3 provided and cover so different areas of a Presssujets on the circumference of the press roll 10 from.

In Figure 4, this arrangement is schematically transferred to a cylinder section through the transfer nip 6 forming press roller 3 and the associated impression cylinder 4 with the direction of rotation. Here, the format documents 30, 31, 32 superimposed on each other in the view and therefore drawn different thickness. The format edges K1, K2, K3 are now located at different peripheral points of the surface of the press roll 3. The press fabric 10 is placed in a line on the substrates 30, 31, 32 and follows their surface contour. To form in the field of format edges K1, K2, K3 fine paragraphs in the surface of the press fabric 10, after the end of a corresponding reduction in pressure in the transfer nip 6 is achieved when there is a sheet together with the voltage applied to the press roller 3 film web 5. Due to the pressure reduction no film transfer can take place there, since the transfer film 5 is no longer clamped. This is shown here with respect to the base 30 and to the associated form edge K1.

Over the width of the press roller 3 results in the same state for the two documents 31 and 32 with respect to the format edges K2 and K3. Thus, the transfer sheet 5 is released in different circumferential positions with respect to the three working areas of the press. Preferably, in this case, the transfer film 5 is divided into three sub-film webs corresponding to the width of the work areas of the press substrate for the size documents 30, 31, 32. Now, if a device for timing according to the above description is provided for each of the sub-webs of the transfer sheet 5, each partial film web can be stopped at the time of release on passage of one of the format edges K1, K2, K3 through the transfer nip 6 in the transport, since they do not more in the transfer nip 6 is clamped. This allows considerable savings in film consumption. The same applies to the adjoining cylinder channel 27.

According to the invention, in the context of the operating conditions of the coating module 2, an adaptation of the drive situation of the drive groups 22, 33 vorgenonnnnen. The following conditions, which are particularly important for print quality, can be taken into account:

The coating quality in cold foil transfer is i.a. influenced decisively by an appropriate adaptation of the web tension conditions in the transfer film 5 when entering the transfer gap and also when leaving the transfer gap 6 for the final result.

Until now, however, the respective effects of the substrate thickness of the currently used substrate have been disregarded, whereby a possibly unavoidable developmental correction on the blanket cylinder would also have to be considered.

In this context, in any case about thicker substrates to maintain an always the same Druckbeistellung the press roller (blanket cylinder) 3 to the impression cylinder 4 to maintain an ideal contact pressure so proceeded that the press roller (blanket cylinder) 3 is set slightly further away from the impression cylinder 4. Accordingly, the press roller (blanket cylinder) 3 is employed somewhat closer to the impression cylinder 4 with thinner substrates.

This results in altered surface speeds, wherein the speed at a substrate with a thicker substrate compared to the press roller 3 is higher than in a corresponding manner with a thinner substrate.

In principle, depending on the respective printing substrate thickness, a development correction of the press roller 3 can be carried out. Such a development correction can be made by changing the elevator thickness on the press roller 3 in a combination of the press fabric 10 and below this underlying underlay sheet. In a so produced Diameter adjustment is a safe synchronization in the transfer nip 6 allows no major change in the film stress.

According to the invention, this procedure should be simplified and improved.

Therefore, it is now provided that an input of a printing material thickness for the film guide should be made. Such an input can be made directly on the one hand on the respective coating module 2.

Alternatively and according to the invention, however, the input can also take place via a control station connection from the coating module 2 to a machine control station in conjunction with the machine control of the sheet-processing machine (sheet-fed press).

In this case, the correspondingly required data in connection with the respectively applied printing material thickness are transmitted from the machine control station to the drives of the drive groups 22, 33 of the coating module 2.

The web tension conditions at the film inlet and outlet of the coating module 2 are then automatically assigned to the film web 5 corresponding to the preselected parameters with respect to the higher or lower conveying speed on the side of the substrate to be coated for the drives of the drive groups 22, 33 in the case of a substrate thickness change.

For this purpose, at least one characteristic field is respectively stored in one or each data memory for the control or the controls of the drives of the drive groups 22, 33. In the characteristic field, drive situations for the transfer film 5 are reproduced, which have been calculated or determined empirically.

The parameter sets reflect the relationship that affects the film transport as a function of the currently available machine speed. Therefore, the parameter sets virtually give a translation requirement of the machine speed to the required film speed. This translation requirement depends on the printing material strength, since this determines the reference surface of the film speed and changed.

Furthermore, the required Bahnzug- / web tension ratios at the inlet into the transfer nip 6 and at the outlet from the transfer nip 6 are taken into account depending on the type of film and / or printing material.

Furthermore, dependencies on the machine speed can also be included in the parameter sets.

The parameter sets shown in the characteristic field thus determined are generally provided in pairs for the film inlet and the film outlet, so that corresponding data are available for each drive group 22, 33. Thus, the web tension conditions in the transfer film 5 before and after the transfer nip 6 can be varied synchronously depending on the circumstances of the settlement conditions in the transfer nip 6.

Therefore, the coating quality is kept constant with changes in the elements involved in the transfer gap 6 as a function of the printing material thickness even if a settlement correction of the press roller 3 should be made. Even if a development correction on the press roll 3 would cause the conditions of web tension or web tension at the film inlet and film outlet to be changed, compensation for the drive groups 22, 33 at the film inlet and at the film outlet can be carried out in the simplest manner, by a corresponding selection of control parameters for the drive motors of the drive groups 22, 33 takes place.

A determination of a family of curves of drive parameters can be carried out in a simple manner by means of tests with different printing materials in different printing material thicknesses and different types of available transfer films 5. In order to determine this, the web tension acting on the transfer film 5 or the web tension in the area of the inlet (film section 5.1) is detected at the transfer nip 6 and in the region of the exit (film section 5.2) after the transfer nip 6. The web tension or the web tension depends on the tivgeschwindigkeit between the substrate surface - ie the effective diameter of the impression cylinder 4 - and the respective drive group 22, 33 for the transfer sheet 5. Furthermore, it is detected, such as with an inspection system, to what extent the film coating in terms of smoothness, gloss and adhesion can meet the desired quality requirements ,

From such a quality consideration, in turn, there are certain preferable operating conditions. At the same time, speed ratios between the speeds applied to the substrate thicknesses to be processed in the transfer nip 6, where the transfer film 5 is clamped, and associated speeds of the drive groups 22, 33 can be detected, at which a coating quality considered necessary can be ensured. From this, the drive parameters are derived, which are to be made available for printing materials according to type and thickness, as well as associated types of transfer film 5.

If a corresponding selection or specification of these drive parameters has an effect on the performance limits of the drive motors of the drive groups 22, 33, quality tolerances can also be specified here. In this way, in favor of performance specifications, a tolerable coating quality can be achieved via a predefinable variation of the drive parameters to be set.

LIST OF REFERENCE NUMBERS

1 applicator

2 coating module

3 press roll

4 impression cylinders

5 transfer foil / foil web

5.1 film section

5.2 Film section

6 transfer gap

7 roller drive

8 foil supply roll

9 foil collecting roll

10 press clothing

1 1 inking / dampening unit

12 plate cylinders

13 blanket / blanket cylinder

14 film guide

15 protective device

16 dryers

17 Inspection device / monitoring system

18 dancer roller

18.1 dancer system, feed storage

18.2 dancer system, acceptance storage

19 web tension measuring device

20 web tear monitoring

21 pressure cylinder blowing device

22 drive group

23 foil guide roller

24 drive roller

25 film guide roller

26 Cylinder channel of the impression cylinder

27 Cylinder channel of the press roll

28 start of printing

29 end of printing Format support

Format pad Format pad 0 impression cylinder 41 blanket cylinder 42 blanket / blanket 43 plate cylinder

44 pressure plate

45 adjusting device

46 adjusting device

47 Register device 48 Mounting pad 50 Printing unit

60 pressure gap

K1 format edge

K2 format edge

K3 format edge

T tangent, tangent line

Claims

claims

Device for cold foil transfer in a sheet-processing machine with at least one applicator (1) for image-wise coating of the printed sheets with an adhesive, with a coating module (2) for transferring the image-forming layers from the carrier film to the printed sheet in a transfer nip (6) a counter-pressure cylinder (4) and a press roller (3), and with a device for feeding the transfer film / film web (5) to the coating module (2) and for discharging from the coating module (2) with one or more conveyors (22, 33) for moving the transfer film (5) in the working direction, wherein the film feed of the transfer film (5) by means of a separate or common control for the conveyors (22, 33) is controllable such that the transport of the transfer film / film web (5) is stopped when in Transfer nip (6) of the coating module (2) no transfer of an imaging layer to a Druc arched, whereby the film transport is stopped, interrupted or started at fixed points in time when conveying the transfer film / film web (5) through the transfer nip (6), wherein when passing through a region of the press roll (3) outside of by format edges (K1 to K3) or format documents (30 to 32) on the area to be coated limited pressing surface of the film feed is stopped and the press roller (3) passes under further contact of the transfer film / film web (5),

characterized in that the or each controller is arranged to be in separate communication with each of the conveyors (22, 33) of the transfer sheet / foil web (5), that the or each controller has a data memory provided with drive control parameter data Conveyors (22, 33) is provided, depending on production parameters in cold foil transfer mutually assigned sets, pairs or groups of drive parameters from the data storage separately selected and each of the conveyors (22, 33) of the transfer film / film web (5) are fed separately , Device according to claim 1,

characterized,

in that the transfer foil / foil web (5) is assigned controllable conveying devices (22, 33) for braking and accelerating the transfer foil / foil web (5) in time with the processing of the cold foil transfer,

wherein the conveyor means (22, 33) are formed as pairs of rollers with at least one motor-driven drive roller (23), wherein the pairs of rollers guide the transfer film / film web (5) by clamping.

Apparatus according to claim 1 or 2,

characterized,

in that the conveyer / film web (5) controllably associated with the film web (5) for conveying and accelerating the film web (5) are driven in such a way as to process the cold foil transfer via the motor drives of the or each drive roll (23)

the web tension of the transfer film / film web (5) in the area between the conveyors (22, 33) is changed in dependence on the feeding of the parameter sets.

Apparatus according to claim 1 or 2,

characterized,

the web tension of the transfer film / film web (5) is changed in the region between one or each of the conveyors (22, 33) and the region of the transfer film / film web (5) clamped in the transfer nip (6) in dependence on the supply of the parameter sets. Device according to one or more of claims 1 to 4,

characterized,

that the controller is arranged so that it is in connection with a machine control of the sheet-processing machine,

in that data sets, pairs or group pairs of drive parameters can be selected from the data store and fed to the respective drives of the conveyors (22, 33) of the transfer film / film web (5) when certain print substrate thickness data are entered on the machine control.

Device according to one or more of claims 1 to 5,

characterized,

in that the control is arranged in such a manner that sets, pairs or groups of drive parameters assigned to the quality features can be selected from the data store and the respective drives of the conveyors (22, 33) of the transfer film / film web (5) if quality characteristics are present on the coated printing material sheet. can be supplied.

Device according to one or more of claims 1 to 6,

characterized,

in that the transfer film / film web (5) is assigned controllable conveying devices (22, 33) for braking and accelerating in time of the film transfer processing in such a way that the transfer film / film web (5), before the transfer to the transfer nip (6 ) is taken from the conveying device (22) to a supply store (18.1) and that the transfer film / film web (5) is fed to a take-off store (18.2) in time with the processing of the film transfer after release from the transfer nip (6) and from the conveyor (33 ) is removed from the removal memory (18.2) and fed to a take-up roll (9).