EP2771189B1 - Film transporting method for a film transferring device - Google Patents

Description

Film transport method for film transfer device

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 and to a method according to the preamble of claim 5.

It is known to produce metallic layers on printed sheets by means of a film transfer process. So is in the EP 0 569 520 B1 a printing material and a printing apparatus using this material are described. In this case, a sheet-processing machine is shown, which has a feeder and a boom, wherein printing units and a coating module are arranged between the two units. In at least one of the printing units, an adhesive pattern is applied by means of the planographic printing process. In the printing module following the coating module with a counter-pressure cylinder and a press roller is a film guide, in which a film strip or a transfer film from a film supply roll through the transfer nip of the coating module and wound on the outlet side of the coating module.

From the 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 of 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 film storage and film promotion special cyclically operable conveyors are assigned for this purpose. In addition, the transfer film are associated with controllable conveyors for braking and accelerating in time to the processing of the film transfer, wherein the conveyors are formed as the transfer film on a drive roller slip-promoting that lead and drive the film web clamping and that the conveyors are assigned to a transfer area in front of the transfer nip and in that the conveying devices are arranged and designed to execute a film return stroke against the direction of production of the film transport during film transfer, the delivery device consisting of a film drive roller and a pressure roller or more distributed over the length of the film drive roller arranged pressure rollers, which are each adjustable to the film drive roller, wherein the transfer film is guided over a wrap angle of at least 90 degrees to the film drive roller. From the DE 10 2010 009 402 A1 is a cold foil transfer with dynamic film tension known. In order to save on film web in a film transfer process, film web is cycled through dancers through a transfer nip. Clocking and the action of the channel in the transfer cylinder produce variations in film tension. This affects the engines of the dancers and should be avoided. In a control system, a control loop acts on the dancer movement. A first process variable in the control loop is formed by the force effect of the transfer foil on the dancers or on the actual movement profile of the dancers.

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 to this problem results in a device according to the features of claim 1 and a method according to claim 5.

The device provides a timing system for guiding the transfer film web, by means of which during operating conditions in which the transfer film is not clamped between the press roll and the substrate, a return stroke of the transfer film web can take place against the production direction.
A suitable cyclic film drive in each case has a dynamically driven drive roller for cyclically moving a transfer film web, wherein the transfer film web is guided around the drive roller by more than 90 degrees, preferably by at least 180 degrees, but also by more than 180 degrees.

In this case, the drive roller adjacent to one or more pressing devices for slip-free coupling of the transfer film web with the surface of the drive roller are arranged.

Such a tactile film drive is arranged in a first embodiment in the transport line of the transfer film web a transfer nip in the film transfer device. In a second embodiment, such a tactile film drive is ever before and arranged downstream of a transfer nip in the film transfer device.

The application takes place when the transfer film web is moved to the press roll in the course of a surface structure interrupting the function of the film transfer. Thus, the film transfer is interrupted when passing through cylinder channels of press roller and impression cylinder in the transfer nip. The film transfer can also be interrupted by a pressing surface structured by means of pressing segments or support elements on the surface of the press roll. The device is therefore used when a pressing surface of a press roll for the film transfer a pressing surface with a partial area of the total area of a Press sheet occupies. In this case, a coating end and a coating start for a coating cycle on a printed sheet are determined by the subject of the coating to be transferred. The tactile foil drive then performs the return stroke movement between the times of the coating end and the coating start.

Figur 1

eine Druckmaschine mit einer Folientransfereinrichtung,

Figur 2

den Aufbau einer Folientransfereinrichtung in Verbindung mit einem Offsetdruckwerk zur Ausführung einer Folientaktung,

Figuren 3 bis 5

schematisch dargestellte Konfigurationen verschiedenartiger Takteinrichtungen in Schnittdarstellung und

Figur 6

eine schematische Darstellung der Taktbewegung der Transferfolienbahn mit einem Folienrückhub.

In the following the invention is illustrated in more detail by means of drawings. Showing:

FIG. 1

a printing machine with a film transfer device,

FIG. 2

the construction of a film transfer device in conjunction with an offset printing unit for performing a film timing,

FIGS. 3 to 5

schematically illustrated configurations of different clock devices in a sectional view and

FIG. 6

a schematic representation of the clock movement of the transfer film web with a Folienrückhub.

• Ein Druckbogen wird zunächst mit einem flächigen oder bildgebenden Klebstoffmuster versehen (Druckwerk als Auftragwerk 1).
• Im Folgedruckwerk wird der Druckbogen gemeinsam mit einer Transferfolie 5 unter Pressung durch einen Transferspalt 6 geführt, (Beschichtungswerk 2).

Das Auftragwerk 1 kann ein an sich bekanntes Offsetdruckwerk mit einem Farbwerk 11, einem Plattenzylinder 12 und einem Drucktuchzylinder 13 sein. Der Drucktuchzylinder 13 wirkt mit einem Gegendruckzylinder 4 zusammen.
Das Beschichtungswerk 2 kann ebenfalls durch ein Offsetdruckwerk gebildet sein. Der Transferspalt 6 im Beschichtungswerk 2 wird durch eine Presswalze 3 und einen Gegendruckzylinder 4 gebildet. Die Presswalze 3 kann dem Drucktuchzylinder entsprechen. Die Presswalze 3 kann auch dem Formzylinder eines Lackmodules entsprechen. Innerhalb des für den Folientransfer genutzten Beschichtungswerkes 2 ist eine Bahnführung 14 für Transferfolien dargestellt. Die Transferfolie 5 wird dabei durch Schutzeinrichtungen 15 des Beschichtungswerkes 2 ein- und wieder ausgeführt.
Dem Beschichtungswerk 2 ist eine Folienvorratsrolle 8 auf der Seite der Bogenzuführung zugeordnet, wobei hierzu ein Drehantrieb 7 zur kontinuierlichen geregelten Zuführung der Transferfolie angeordnet ist. Auf der ablaufseitigen Seite des Druckwerkes ist eine Foliensammelrolle 9 für das verbrauchte Folienmaterial vorgesehen, der ein Drehantrieb 7 zugeordnet ist. 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 imaging adhesive pattern (printing unit as commissioned work 1).
• In the following printing unit, the printed sheet is guided 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 may also correspond to the forme cylinder of a paint module. Within the coating unit 2 used for the film transfer, a web guide 14 for transfer films is shown. The transfer foil 5 is on by protective devices 15 of the coating unit 2 on and executed again.
The coating unit 2 is associated with a film supply roll 8 on the side of the sheet feed, for which purpose a rotary drive 7 is arranged for the continuous controlled feeding of the transfer film. On the downstream side of the printing unit, a film collecting roller 9 is provided for the used sheet material, which is associated with a rotary drive 7.

The press roll 3 (as a blanket cylinder or forme cylinder or separate press roll) carries on its surface a compressible or damping press fabric 10, for example as a plastic coating, comparable to a rubber or blanket, which is held in a cylinder channel on jigs.

An improvement in the film utilization is also obtained 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 sub-film webs, the utilization of the transfer film 5 can be improved even in zonally different lengths coating areas within an arc.

Dryer 16, such as UV dryers, for drying the adhesive application or the entire film coating are assigned to the film transfer module.
The transport of the transfer film 5 can be monitored on or between film guide rollers 14 by means of web tension measuring devices 19.
Electrical signals of the web tension measuring devices 19 are evaluated. Various operating states are possible for this:

To stabilize the film web 5, a stabilizing device 30 with two rotatably mounted rollers can be arranged in front of the transfer gap.

The film transfer process is described in the described printing or application machine according to FIG. 1 executed. It is provided, at least in a printing unit 50 following the coating unit 2, a color print on with a metallized layer imagewise coated sheet to apply. Here, the sheet from the coating unit 2 is transferred from the impression cylinder 4 via a sheet transfer drum or a sheet transfer unit to a counter-pressure cylinder 40 of the printing unit 50.
The printing unit 50 has as an offset printing unit a counter-pressure cylinder 40, a rubber cylinder associated therewith 41 and a plate cylinder associated therewith 43, which here schematically shown a color and a dampening unit are assigned. Between counter-pressure cylinder 40 and blanket cylinder 41, a 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 pressure 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, 46. 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.

1. I. Die Taktung des Vorschubs der Transferfolie 5 kann beim Kanaldurchlauf und auch dann ausgeführt werden, wenn der zu beschichtende Bereich innerhalb des Bildbereiches des Druckbogens liegt.
2. II. Eine weitere Verbesserung der Folienausnutzung der beschriebenen Art ergibt sich, wenn die Transferfolie 5 in eine oder mehrere Teilfolienbahnen geringerer Breite aufgeteilt wird. Die ist insbesondere in Verbindung mit der segmentierten Pressfläche von großem Vorteil.

Furthermore, as a surface of the press roll 3, a smooth or contoured or segmented press surface in the press fabric 10 should also be provided. For this purpose, segmented pressing areas limited to one or more areas to be coated are used on the press roller 3 in addition to a full-surface pressing area. The function of the limited segmented pressing surface in the press fabric 10 is that the entrapment of the transfer film 5 is given only when the segmented pressing surface the transfer film 5 touching passes through the transfer nip 6 and by the contact pressure generated thereby forming layers of the transfer sheet 5 on the sheet to be transferred.
Thus, two effects can be achieved in a coating module 2 with a segmented pressing surface provided in a press fabric 10:

1. I. The timing of the feed of the transfer film 5 can be performed in the channel pass and even when the area to be coated is within the image area of the sheet.
2. II. 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. This is particularly advantageous in connection with the segmented pressing surface.

In the aforementioned method, different types of films can be used side by side, whereby surfaces of different film color or different smoothness or structure can be produced.

• eine Kanaltaktung beim Durchlauf von Zylinderkanälen der Presswalze 3 und des Gegendruckzylinders 4,
• eine Formattaktung bei auf die Formatlänge des Folientransfers am Umfang der Presswalze 3 beschränkter Folienzuführung und
• eine Prägebereichstaktung bei Beschränkung der Folienführung auf durch segmentierte Pressbereiche in der Pressbespannung 10 der Presswalze 3 definierter Folienzuführung

ausgeführt werden.
Für die Folienzuführung (auch die Abführung) ist üblicherweise der Antrieb der Folienrollen 8, 9 kontinuierlich vorgesehen, da die Masse der Folienrollen 8, 9 zu groß für einen schnellen Wechsel der Antriebsbewegung ist. Dadurch ergeben sich beim Abbremsen der Folienbahn bis zum erneuten Beschleunigen im Transferbereich in den Zu- und Abführbereichen der Folienbahn 5 gegenüber der Bewegung der Folienrollen 8, 9 überschüssige oder fehlende Folienlängen.For this purpose, devices for cyclically conveying the film web 5 are provided. As operating variants from the previously executed can

• 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 on segmented pressing areas in the press fabric 10 of the press roll 3 defined film feed

be executed.
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. 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, facilities are provided which can buffer the incurred in continuous Nachförderung or removal of the film web 5 excess or missing pieces of track. The dancer rollers 18 are not accurately enough as a foil stores on the described running at a high speed timing in the film transfer process controllable and are far away from the place of consumption. They maintain close to the film rolls 8, 9, the web tension.

• Durch absaugen von Luft mittels eines Unterdruckaggregates 32.3, etwa als gemeinsames Aggregat gebildet aus einem oder mehreren Lüftern, an der Boden- oder Oberseite der Unterdruckkammern der Folienspeicher 32.1 und 32.2 wird jeweils eine Folienschlaufe 36 mit einer gemäß dem Verhältnis zwischen der sich aus dem erzeugten Unterdruck und dem Spannung der Transferfolienbahn 5 einstellenden Kraft in jede der Unterdruckkammern der Folienspeicher 32.1 und 32.2 hineingezogen. Diese die Folienschlaufe 36 bildende und haltende Kraft überwiegt nicht die von der Bahnspannungsregelung vorgegebene Zugkraft der Transferfolienbahn 5, da die Folienschlaufen 36 sonst in der Unterdruckkammern festgesaugt und damit blockiert würden. Das System ist insofern selbstregulierend als die Folienschlaufen 36 gegen die Kraft des Unterdrucks frei in den Unterdruckkammern pendeln können und so jeweils Teillängen der Transferfolienbahn 5 aufnehmen oder freigeben.

FIG. 2 shows an arrangement for rapid compensation of path shifts in the film timing in the cold foil transfer process. The storage effects in the film timing uses a per se known principle of looping of the film web by negative pressure. In this case, film stores 32.1 and 32.2 in the form of vacuum chambers are assigned to the transfer film web guide in the coating unit 2.
The effect of the film stores 32.1 and 32.2 is as follows:

• By sucking air by means of a vacuum unit 32.3, as a common aggregate formed from one or more fans, at the bottom or top of the vacuum chambers of the film storage 32.1 and 32.2 each a film loop 36 with a according to the ratio between the generated from the negative pressure and the tension of the transfer film web 5 adjusting force in each of the vacuum chambers of the film storage 32.1 and 32.2 pulled. This forming the film loop 36 and holding force does not exceed the predetermined by the web tension control tensile force of the transfer film web 5, since the film loops 36 would otherwise be firmly sucked in the vacuum chambers and thus blocked. The system is self-regulating insofar as the film loops 36 can oscillate freely against the force of the negative pressure in the vacuum chambers and thus absorb or release partial lengths of the transfer film web 5.

To control the film web conveyance, the size of the film loops 36 can be used. For this purpose, a sensor system can be provided within each vacuum chamber to the film stores 32.1 and 32.2, which is based for example on a distance measurement by means of ultrasound. This sensor detects how far the film loop 36 is pulled 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.

To maintain the web tension of the transfer film web 5 and to ensure its perfect guidance can of course continue to be the negative pressure, which is generated by means of the vacuum unit 32.3 in the vacuum chambers of the film storage 32.1, 32.2, regulated. This will be the Depending on the process required training of the film loops 36 ensured at any time to a sufficient extent.

1. a) Zum Anhalten Folientransfers und damit auch des Folientransportes im Transferbereich (Transferspalt 6) wird durch das Stillsetzen der Antriebsgruppe 33 vor dem Transferspalt 6 bei laufender Folienrolle 7 eine auflaufende Folienbahnlänge frei und in den ersten Folienspeicher 32.1 hineingezogen.
2. b) Auf der Ablaufseite nach dem Transferbereich wird gleichzeitig die Folienbahn 5 aus dem zweiten Folienspeicher 32.2 zur kontinuierlichen Aufwicklung auf der Foliensammelrolle 9 freigegeben.
3. c) Zum Fortsetzen des Folientransfers und damit dem erneuten Einsetzen des Folientransportes im Transferbereich wird die Antriebsgruppe 33 wieder aktiviert und die eingezogene Folienschlaufe 36 aus dem ersten Folienspeicher 32.1 wieder dem Transferbereich zugeführt.
4. d) Gleichzeitig wird der zweite Folienspeicher 32.2 wieder mit einer Folienschlaufe 36 befüllt.

The arrangement of the film storage 32.1, 32.2 serves to ensure that the timing of the film web feed when stopping and continuing the film transport in the transfer area can be carried out as follows:

1. a) To stop film transfers and thus also the film transport in the transfer area (transfer nip 6) by pulling the drive group 33 in front of the transfer nip 6 with the film roll 7 running a length of film web free and pulled into the first film memory 32.1.
2. b) On the discharge side after the transfer area, the film web 5 is simultaneously released from the second film storage 32.2 for continuous winding on the film collection roller 9.
3. c) To continue the film transfer and thus the reinsertion of the film transport in the transfer area, the drive group 33 is activated again and fed the film loop 36 fed from the first film memory 32.1 back to the transfer area.
4. d) At the same time, the second film store 32.2 is again filled with a film loop 36.

In FIG. 2 the film stores 32.1 and 32.2 are shown in the coating unit 2 according to the functions shown. The film storage 32.1 and 32.2 are arranged approximately perpendicularly adjacent to the unwinding roll 8 parallel to each other. A first drive group 33 is arranged with two film guide rollers 35 and a drive roller 34 on the feed side of the transfer area close to the transfer nip 6. Another drive group 37 with two film guide rollers 39 and a drive roller 38 is assigned to the film storage 32.2 on the discharge side from the transfer nip 6 forth. This arrangement makes the feeding of the film web 5 from the film loop 36 in the film store 32.1 compact and allows a smooth feed of the film web 5 to the first drive group 33 via the smoothing and stabilizing device 30.
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 Folienleitelemente 14 (in the type 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 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. The film guide roller 31 can also be designed as a fixed deflection shaft. The film guide roll 31 can furthermore be ventilated, so that an air cushion is established between the transfer film web 5 and the film guide roll 31 in order to reduce the friction of the transfer film web 5.

The vacuum chambers of the film storage 32.1 and 32.2 can be performed according to leading foil or Teilfolienbahnen. If these 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 32.1 and 32.2 can be divided advantageously into several parallel vacuum chambers. If separators 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 are tunable to individual film webs 5 of different widths or partial film webs of the same or different widths. Thus, the formation of film loops 36 is improved and tailored to each leading to foil or Teilfolienbahnen.

In FIG. 3 one of the aforementioned drive groups 37 is shown in a first technical embodiment for the withdrawal of the transfer film web 5 from the working area in the transfer nip 6. This working group 37 is in accordance with FIG. 2 in a section U the film storage 32.2 upstream. In the drive group 37 is in a housing 72, a film drive roller 70 is coupled to a clock drive 71 which controls the movement of the film drive roller 70 highly dynamically.

The drive roller 70 shown here corresponds to FIG. 2 the drive roller 38. The drive roller 70 is assigned in the illustrated embodiment, a plurality of groups or evenly distributed in the axial direction of the drive roller 70 and freely rotatably mounted on an axis pinch rollers 24. The pinch rollers 24 are connected to a pivotable and revolving panel element 73 of the drive group. In this way, the pressure rollers 24 can be pivoted away from the film drive roller 70 for insertion of the film web of the transfer film 5 and then swung back again. The setting of the position of the elastic pressure rollers 24 is selected in the working position so that the inserted transfer film is pressed against the film drive roller 70 without deforming or damaging them. In addition, this is chosen so that the inserted transfer film 5 is pressed against the film drive roller 70, so that the transfer film 5 can be conveyed with or without slippage through the conveying nip.
The transfer film 5 is fed to and removed from the film drive roller 70 via film guide rollers 23, so that a wrap of more than 90 degrees is formed. A wrap of the transfer film 5 of about 180 degrees or more on the film drive roller 70 is advantageous. This ensures good film guidance and additional friction surface for secure film transport.
The drive group 37 is designed so that the transfer film 5 in a feed strand 5A from a film store (32.1, see Fig. 2 ) supplied to the transfer nip 6 and further from the transfer nip 6 a further film storage (32.2, see Fig. 2 ) can be supplied. This type of film web guide is dependent on the respective arrangement of the elements to each other, the solution shown is based on the fact that the film storage 32.1, 32.2 are arranged parallel to each other and coupled directly to each other. This creates a very easy to handle film guide in an extremely compact design.

When said drive group 37 after FIG. 3 used as a second drive group for the removal of the outgoing film strand 5B of the transfer film web 5 from the transfer nip 6 to the film storage 32.2 after the transfer nip 6 is, the drive motor of the film drive roller 70 may also be set as continuously running. Then the drive group 37 continuously pulls film web to ensure a continuous film removal of the used transfer film 5 to the film collecting roll 9. On the other hand, the foil conveyance is interrupted at idle film web in clock mode and the drive group 37 then runs in the slip mode against the expiring film strand 5B. Therefore, in the aforementioned case, a larger looping of the film drive roller 70 through the film strand 5B of the transfer film web 5 is not required or rather a hindrance, since only a minimum web tension for conveying away maintained otherwise but also slippage must be allowed.

The compact design of the drive group 37 in the housing 72 is further improved in an association with the first film memory 32.1 that in the same housing 72 and a Folienleitwalze 23.1 for discharging the transfer film web 5 in a Zuführstrang 5A from the first film memory 32.1 for feeding in the direction of Transfer nip 6 is arranged.
For this purpose, the drive group 37, as well as in FIG. 2 is shown, arranged in the immediate vicinity of the open end faces of the film storage 32.1, 32.2. The film guide roller 23.1 corresponds to the film guide roller 31, which is the drive group 37 and the film guide roller 39 next.

In FIG. 4 is a further drive group for the functionality of the supply of the provided film strand 5A according to the drive group 33 in FIG FIG. 2 shown in a second technical embodiment.
Therein, in a housing 72, a film drive roller 70 is coupled to a clock drive 71, which controls the movement of the film drive roller 70 in any movement cycles highly dynamically. The drive roller 70 is associated with a freely rotatably mounted pressure roller 25 with preferably smooth elastic surface. The pressure roller 25 is coupled to a swiveling and swiveling cladding element 73 of the drive group. Thus, the pressure roller 25 can be pivoted directly or indirectly via a Getriebeanlenkung during pivoting of the cladding element 73 of the film drive roller 70 for introducing the film web of the transfer film 5 and then swung back. The Position of the pressure roller 25 is selected in the working position so that the inserted transfer sheet 5 is pressed against the film drive roller 70 without deforming or damaging them. In addition, this is chosen so that the inserted transfer film 5 is pressed against the film drive roller 70, so that the transfer film 5 can be promoted as possible slip.
The transfer film 5 is fed in this embodiment of the film drive roller 70 via a pressure roller 23 and discharged via the pressure roller 25 again, so that a wrap of more than 90 degrees. Advantageously, a looping of the transfer film web 5 on the film drive roller 70 of about 180 degrees or more, as in the aforementioned embodiment according to Fig. 4 is shown. This ensures good film guidance and additional friction surface for safe film transport.

In FIG. 5 is a further drive group shown in a third technical embodiment. Therein, in a housing 72, a film drive roller 70 is coupled to a clock drive 71 indicated here, which controls the movement of the film drive roller 70 continuously or highly dynamically.
The embodiment shown here again corresponds to the drive group 37 in FIG. 2 (detail U), wherein a film strand 5A to be supplied to the transfer nip 6 is guided by a film guide roller 23.1 in one direction. Furthermore, a foil strand 5B to be removed from the transfer nip 6 of the used transfer film web 5 from the drive group 37 is fed to a film store (32.2, see FIG Fig. 2 in section U), from where the transfer film web 5 is then removed from the film collecting roller 9.

The drive roller 70 is associated with a contact pressure segment 26 with a substantially smooth inner guide surface 26.1. The inner guide surface 26.1 is adapted to the contour of the film drive roller 70 and engages around the film drive roller 70 by about 180 degrees.
The contact pressure segment 26 is coupled to an upwardly and downwardly pivotable trim element 73 of the drive group. Thus, the Andrucksegment 26 can be removed during pivoting of the cladding element 73 of the film drive roller 70 for insertion of the film web of the transfer film 5 and then back to this be employed. The position of the Andrucksegments 26 is determined in the working position by a holding device 29. In this case, the contact pressure segment 26 is pressed by means of a force-controlled, such as resilient, acting on the Andrucksegment 26 holding device 29 in the direction against the film drive roller 70 and set relative to the film drive roller 70.

In the Andrucksegment 26, a Blasluftzufuhr 28 is integrated, via which a Blasluftstrom from arranged in the guide surface 26.1 fine outflow in a nip acting clearance between the guide surface 26.1 of Andrucksegments 26 and the film drive roller 70 and the transfer sheet 5 resting on this is introduced. The outflow openings are preferably in the central region of the guide surface 26.1 and are evenly distributed over at least the entire length of the film drive roller 70. They can also be distributed in the circumferential direction to the film drive roller 70. The strength of the blast air flow is adjustable in terms of quantity and pressure. Furthermore, the blast air is switched on and off depending on the operation.

The pressure of the blowing air is selected so that the inserted transfer film 5 is pressed by the pressure in the nip against the film drive roller 70, so that the transfer film 5 can be promoted as possible slip. The transfer film 5 is in this embodiment of the film drive roller 70 via film guide rollers 23 and discharged again, so that a wrap of more than 90 degrees. Advantageously, a wrap of the transfer sheet 5 of about 180 degrees or more, as in the aforementioned embodiment according to Fig. 4 is shown. This ensures good film guidance and additional friction surface between the film drive roller 70 and the transfer film web 5 for secure film transport. On the other hand, friction on the contact pressure segment 26 is reliably prevented during production, so that unimpeded film transport can take place.

In the solution shown here, the Blasluftzufuhr to Andrucksegment 26 can be switched off at standstill of the printing press, so that the Andrucksegment 26 by means of the resilient (or air pressure) employed Andruckeinrichtung 29 against the film drive roller 70 and the transfer sheet 5 possibly guided thereon is pressed. In this case, the transfer film web 5 is held in contact with the film drive roller 70 in a contacting manner by means of the contact pressure segment 26.
In the state with promotion of the transfer film 5 during production with inserted transfer film web 5 blowing air is supplied to the Andrucksegment 26, which enters the gap between the guide surface 26.1 and the transfer film web 5 on the film drive roller 70. In this case, an overpressure builds up in the contact pressure gap between the contact pressure segment 26 or its guide surface 26.1 and the film drive roller 70 or the transfer film 5 guided thereon. As a result of this acting as a planar contact pressure air overpressure lifts the Andrucksegment 26 of the film drive roller 70 and the transfer sheet 5 against the force of the resilient (or air pressure) employed Andruckeinrichtung 29 from. In this case, the transfer film web 5 is now uniformly pressed against the film drive roller 70 over the entire area of the guide surface 26.1. The force of the contact pressure is dependent on the setting of the contact force, that is, for example, a spring force or a pneumatic device on the adjusting device 29. Against this contact force is formed by the air pressure in the gap between the guide surface 26.1 and the film drive roller 70 and the transfer film web 5, a balance of power.

If the Andrucksegment 26 is not to be employed by means of a self-regulating pressure device 29 by spring force (air pressure) against the film drive roller 70, this can also be performed by means of a pivoting mechanism at a distance from the surface of the film drive roller 70 adjustable.

In connection with the guidance of the transfer film web 5, guide shafts with air outlet openings can also be provided to reduce friction and thus facilitate the guidance of the transfer film 5. There, the transfer film web 5 can then be guided without friction on an air cushion. Frictional or inertial forces of rotating rollers then also act on the transfer film so that it is less prone to distortion and wrinkling.

Furthermore, a film guide in the manner of a spreader roll may be provided in a preferred manner in the region of the film feed to a drive group. This arrangement is assigned in a preferred manner to a drive group 33 for the film feed a film strand 5A to the transfer nip 6. Such a spreader roll can be embodied as a deflection roll which can be deflected radially in the axis, wherein a deflection is preferably carried out in the region of the center of the deflection roll, so that the transfer film web 5 is stretched in width toward the side edges and thereby smoothed. Thus, the drive group can be easily fed for a flat film transport and for a subsequent high-quality transfer coating.

To support the film transport, the film drive roller 70 can also be designed as a suction roller with finely distributed suction openings for sucking the applied transfer film 5. With appropriate suction, this embodiment can also be operated without pressure elements.

For guiding film webs of the transfer film 5 of narrower width or for guiding partial film webs of the transfer film 5 next to one another, the film drive roller 70 can be segmented with a plurality of juxtaposed drive roller segments. In this case, each drive roller segment is coupled to its own clock drive 71, so that the clocking of the transfer film drive can be controlled separately only in a specific processing area or for each partial film web in its processing area.

According to the invention, it is now provided, for the further improvement of the film savings, to provide at least one arrangement of drive groups 33, 37 with a respective clock drive 71 on both sides of the transfer gap 6 in the film transfer module 2. With a suitable control, a return stroke movement of the transfer film web 5 is carried out according to the invention during the coating cycle of a printing sheet between a coating end (subject end) and a coating beginning (beginning of the subject). When performing a Folienrückhubes means of the drive group 33 on the film inlet side is in the outlet side drive group 37th by means of the drive motor 71 via the film drive rollers 38 or 70 also carried out a Folienrückhub.
If an active film return stroke is not intended or possible on the outlet side, then the transfer film web 5 can also be released on the outlet side for carrying out the film return stroke. Then, in the drive group 37, the transfer film 5 is released from the frictional connection necessary for the film transport, so that there is no frictional connection in the drive group 37 nor can an active film transport take place.
For this purpose, in the drive groups 37 according to the embodiments according to Figures 2 and 3 the corresponding pinch rollers 23, 24, 39 are lifted off the film drive roller 38, 70 of the transfer film web 5.
In the embodiment of the drive group 37 after FIG. 5 On the other hand, the blowing air for pressing the transfer film web 5 to the film drive roller 70 can be turned off or reduced in order to reduce the contact pressure of the transfer film web 5 against the film drive roller 70. Also, the Andrucksegment 26 can be switched off via a control circuit clockwise by the film drive roller 70, so be removed to a small extent, in which case the Anpressspalt the transfer film web 5 slightly opened and the friction of the transfer film web 5 is reduced or canceled to the film drive roller 70, then again the Anpressspalt for the transfer film web 5 to close for further film transport.

As a result of the high speeds during coating by means of a sheetfed offset printing machine, the transfer film web 5 can be braked during clocking for a complete execution of the film transfer in the print subject only with the outlet or even shortly after the end of the area to be coated (Sujetende). Furthermore, the acceleration of the transfer film web 5 has to be initiated again shortly before the beginning of the newly starting area to be coated (beginning of the plot). This results in additional losses of film surface, which can not be used for the coating. These non-usable film surfaces can according to the invention by one within the current production speed and the distance between Sujetende and Sujetanfang matched film return stroke against the production direction of the transfer film 5 are minimized by means of the drive groups.

For this purpose, the drive groups 33, 37 in the manner of the FIGS. 3 to 5 executed and each equipped with a highly dynamic cycle drive 71 for film transport.
As has already been described above, the drive motor 71 of the film drive roller 38, 70 can also be designed as a continuously running motor if the drive group is to be used on the outlet side in front of a film store for the removal of the used transfer film web.
The film return stroke which can be carried out by the clock drive 71 via the film drive roller 70 on the transfer film 5 is adjusted with respect to the film surfaces which remain unused in the coating cycle.

The working principle is in connection with FIG. 6 to describe as follows.
The transfer sheet 5 is usually moved at the same speed that corresponds to the surface of the paper or printed sheet. This is also the speed of the surface of the counter-pressure cylinder 4 or of the press roll 3, whereby here the relative position of the surfaces is taken into account, taking into account the thickness of the applied printing material.
In FIG. 6 Therefore, a diagram is shown which indicates the speed of the transfer film web 5 on the circumferential position of the impression cylinder 4 in the transfer nip 6. The reference position of the transfer nip 3 and the press roller 3 are symbolically indicated here.
Here, the horizontal axis of the diagram is represented as a path over the circumference of the impression cylinder 4, while the vertical axis represents the velocity profile of the transfer film web 5 in the production direction R as a positive speed X and in the return stroke as a negative speed Y. Therefore, a positive velocity X results in a film transport in the production direction R, the zero position of the speed means film discontinuity and a negative velocity Y results in a film transport counter to the production direction R, ie a film return stroke.

The production speed X, A1, A2 is predetermined here by the operating speed of the sheet-fed offset printing press in the production process. The foil transport takes place when the cold foil transfer takes place at precisely this speed, since the transfer foil 5 must be guided to a high degree synchronously with the printing sheet S for good coating quality.

In FIG. 6 schematically the area of the impression cylinder 4 is shown, which has a cylinder channel 80 with a front and a rear channel edge 81.1, 81.2. On the counter-pressure cylinder 4, a printed sheet S is guided in grippers 82 on its front edge associated with the front channel edge 81.1. At certain distances to each end of the printing sheet S and thus also to each of the channel edges 81.1, 81.2, a boundary of a Drucksujets 83 is defined, which is provided on the sheet S. A limitation for a relative movement of the film transport results here from the length of the printing sheet S, on which the transfer film 5 rests and from the edge regions of the Drucksujets 83, which in turn results from the closest to the paper edge and to be coated with metal foil areas.

A1, A2, A3

Arbeits-/Produktionsgeschwindigkeit

B1, B2

Vorwärts-/Rückwärtsverzögerung

C1, C2

Vorwärts-/Rückwärtsbeschleunigung

D1, D2

Umschaltrast von Vorwärts- auf Rückwärtslauf und umgekehrt

E1, E2

Sicherheitsschaltabstand zu den Sujeträndern

In the course of movement of the transfer film web 5, the following process conditions result cyclically

A1, A2, A3

Work / production speed

B1, B2

Forward / reverse delay

C1, C2

Forward / backward acceleration

D1, D2

Shifting from forward to reverse and vice versa

E1, E2

Safety distance to the Sujeträndern

The aforementioned safety switching distance E1, E2 between edges 83.1, 83.2 of the Drucksujets 83 and the respective channel edges 81.1 and 81.2 is provided so that a consistent coating quality for the cold foil transfer within the entire Drucksujets 83 can be maintained up to both edges 83.1, 83.2.

The safety distances E1 and / or E2 can be minimized depending on the nature of the Drucksujets 83 within the sheet S at a sufficiently large distance from the front and rear paper edge. Then a restriction of the safety distances E1 and E2 on the distance of the paper edges of the sheet S to the front and rear channel edge 81.1, 81.1 from, in which case the film consumption is further reduced.
The production speed X, A1, A3 is hereby predetermined by the operating speed of the sheet-fed offset printing press in the production process. The foil transport takes place when the cold foil transfer takes place at precisely this speed, since the transfer foil 5 must be guided to a high degree synchronously with the printing sheet S for good coating quality.

• Annäherung des Transferspalts 6 auf dem Gegendruckzylinder 4 an die hintere Kanalkante 81.2, die Transferfolienbahn 5 wird mit Produktionsgeschwindigkeit A1 in Produktionsrichtung R bewegt.
• Transferspalt 6 liegt innerhalb Sicherheitsabstand E1 vom hinteren Rand 83.2 des Drucksujets 83, weiterhin Produktionsgeschwindigkeit A1; Beendigung des Kaltfolientransfers auf dem aktuellen Druckbogen S
• Transferspalt 6 liegt mindestens mit Sicherheitsabstand E1 zum hinteren Rand 83.2 des Drucksujets 83, Vorwärtsverzögerung B1 in Form einer Bremsrampe aus der Produktionsgeschwindigkeit A1 bis zum Stillstand der Transferfolienbahn 5
• Umschaltrast D1 des Taktantriebs 71 aus dem Vorwärtslauf in den Rückwärtslauf im Stillstand der Transferfolienbahn 5
• Rückwärtsbeschleunigung C1 des Taktantriebs 71 mit Folienrückzug der Transferfolienbahn 5
• Rückfördergeschwindigkeit A2 über maximal mögliche Zeitdauer mit Folienrückzug der Transferfolienbahn 5 oder Abbremsen bei maximal möglichem Weg für den Folienrückzug (Wegbegrenzung abhängig von Brems- und Beschleunigungsrampen)
• Rückwärtsverzögerung C2 des Taktantriebs 71 aus der Rückfördergeschwindigkeit A2 bis zum Stillstand der Transferfolienbahn 5
• Umschaltrast D2 des Taktantriebs 71 aus dem Rückwärtslauf in den Vorwärtslauf im Stillstand der Transferfolienbahn 5
• Annäherung des Transferspalts 6 an die vordere Kanalkante 81.1, Vorwärtsbeschleunigung B2 des Taktantriebs 71 in Form einer Beschleunigungsrampe vom Stillstand der Transferfolienbahn 5 bis auf Produktionsgeschwindigkeit A1
• Erreichen der Produktionsgeschwindigkeit A1 mindestens im Sicherheitsabstand E2 vordem vorderen Rand 83.1 des Drucksujets 83 nach Passieren der Greifer 82 durch den Transferspalt 6
• Transferspalt 6 innerhalb des Sicherheitsabstands E2 vom vorderen Rand des Drucksujets 83, Transferfolienbahn 5 in Produktionsgeschwindigkeit A1
• Transferspalt 6 im Drucksujets 83, weiterhin Produktionsgeschwindigkeit A1 der Transferfolienbahn 5 und Beginn des Kaltfolientransfers auf dem nachfolgenden neuen Druckbogen S

The aforementioned states result in a duty cycle for a film cycle with sheet breakage and activated sheet return stroke, as follows FIG. 6 the processes against the production direction R are to be considered. In this case, in each case the film movement is considered relative to the transfer nip 6 in relation to the position of the transfer nip 6 with respect to the impression cylinder 4:

• Approach of the transfer gap 6 on the impression cylinder 4 to the rear channel edge 81.2, the transfer film web 5 is moved at production speed A1 in the production direction R.
• Transfer nip 6 is within safety distance E1 from the rear edge 83.2 of Drucksujets 83, continue production speed A1; Termination of the cold foil transfer on the current print sheet S
• Transfer nip 6 is at least at safety distance E1 to the rear edge 83.2 of Drucksujets 83, forward delay B1 in the form of a braking ramp from the production speed A1 to the standstill of the transfer film web fifth
• Shifting load D1 of the clock drive 71 from the forward run to the reverse run at standstill of the transfer film web fifth
• Reverse acceleration C1 of the clock drive 71 with film retraction of the transfer film web fifth
• Return feed rate A2 over the maximum possible time with film retraction of the transfer film web 5 or braking at the maximum possible path for film retraction (path limitation depending on braking and acceleration ramps)
• Backward delay C2 of the clock drive 71 from the return speed A2 to the standstill of the transfer film web. 5
• Shifting load D2 of the clock drive 71 from the reverse run in the forward run at a standstill of the transfer film web fifth
• Approach of the transfer gap 6 to the front channel edge 81.1, forward acceleration B2 of the clock drive 71 in the form of an acceleration ramp from standstill of the transfer film web 5 up to production speed A1
• Achieving the production speed A1 at least at the safety distance E2 before the front edge 83.1 of the Drucksujets 83 after passing through the gripper 82 through the transfer nip. 6
• Transfer nip 6 within the safety distance E2 from the front edge of the Drucksujets 83, transfer film web 5 in production speed A1
• Transfer nip 6 in Drucksujets 83, continue production speed A1 of the transfer film web 5 and the beginning of the cold foil transfer on the subsequent new sheet S

During cycle operation, motion sequences for braking and acceleration of the transfer film web 5 are thus switched to minimize the consumption of transfer film 5, so that depending on the length of the work area on the sheet S and the press roller 3 or the impression cylinder 4, in which no cold foil transfer can or should take place, the transport of the transfer film web 5 is stopped.

In this case, the print quality for the cold foil transfer is ensured up to the edges 83.1, 83.2 of the Drucksujets 83, in which for the braking and acceleration operations safety distances E1, E2 are adhered to the areas to be coated. At the same time, deceleration, acceleration and standstill times are selected so that maximum foil savings are achieved.

• Im Bereich der Sicherheitsabstände E1, E2 läuft Transferfolie 5 ungenutzt weiter, was aus Sicherheitsgründen nicht eingespart werden kann. Während der Brems- und Beschleunigungsphasen B1 und C2 in Produktionsrichtung R läuft die Transferfolie 5 ebenfalls ungenutzt weiter, wobei dieser Folienverbrauch aus technischen Gründen nicht vollständig beseitigt werden kann.

Daraus ergibt sich am Beginn der Folientaktung ein Bremsverlust Z1, der von der Größe des Sicherheitsabstandes E1 zum Sujetende 83.1 und von der Einstellung der Bremsrampe B1 hinsichtlich ihrer Steilheit abhängig ist.
Weiterhin ergibt sich am Ende der Folientaktung ein Beschleunigungsverlust Z2, der von der Größe des Sicherheitsabstandes E2 zum Sujetanfang 83.2 und von der Einstellung der Beschleunigungsrampe C1 hinsichtlich ihrer Steilheit abhängig ist, wobei die Beschleunigungsphase spätestens bei Beginn des Sicherheitsabstandes E2 abgeschlossen sein muss.This results in the following tuning parameters:

• In the area of the safety distances E1, E2 transfer film 5 continues unused, which can not be saved for security reasons. During the braking and acceleration phases B1 and C2 in the production direction R, the transfer film 5 also continues unused, and this film consumption can not be completely eliminated for technical reasons.

This results in the beginning of the film timing brake loss Z1, which is dependent on the size of the safety distance E1 to Sujetende 83.1 and the setting of the brake ramp B1 in terms of their steepness.
Furthermore, at the end of the film timing results in an acceleration loss Z2, which depends on the size of the safety distance E2 Sujetanfang 83.2 and the setting of the acceleration ramp C1 in terms of their steepness, the acceleration phase must be completed at the latest at the beginning of the safety distance E2.

Finally, the path length is obtained as the actual film saving Z, while the transfer film web 5 is at a standstill (see D1, D2) or in the return stroke movement (see C1, A2, D2). This as a minimum value to be understood foil saving Z is in FIG. 6 shown correlating to the path of the impression cylinder 4 in the transfer nip 6, while the transfer film web 5 is at least at a standstill.

In addition, the foil return stroke, which is intended to minimize the brake losses Z1 and the acceleration losses Z2, also comes into play as foil saving. The size of the Folienrückhubes depends on how much time in the production cycle between the braking and acceleration operations for stopping the film movement is available.
For the execution of the Folienrückhubes is to be considered that the clock drive 71 must be switched for each return movement from the forward to the reverse, which represents another unusable delay. Therefore, with short downtimes a Folienrückhub also not executable or so technically negative. These situations result from small distances between the channel edges or those to be considered for the film timing Sujeträndern or Formaträndern or even at very high production speeds, the latter can be variable depending on the pitch.

When carrying out the film saving measures, it must furthermore be taken into consideration that a film return stroke may not be carried out in this respect or may be carried out only to a limited extent, since a complete transfer layer must be present on the transfer film web 5 for each cycle of the cold foil transfer. Therefore, the Folienrückhub can consist of short cycles or completely shut off when the saving value is too low.

• Bei schneller Beschichtungsproduktion kann wegen der hohen Produktionsgeschwindigkeiten und damit verbunden sehr kurzen Taktpausen der Folienrückhub abgestellt werden.
• Bei reiner Kanaltaktung im Bereich der Zylinderkanäle wird die Ansteuerung des Folienrückhubs auf maschinenabhängig festliegende Winkelwerte eingestellt, der winkelabhängig angesteuert wird und die Brems- und Beschleunigungsrampen, sowie die Sicherheitsabstände berücksichtigt.
• Bei einer so genannten Sujettaktung der Transferfolienbahn wird der Folienrückhub variabel auf die Umfangslänge zwischen Rändern 83.1, 83.2 des Drucksujets 83 am Sujetende und Sujetanfang abgestimmt, wobei Brems- und Beschleunigungsrampen und Sicherheitsabstände einzurechnen sind.
• Bei einer variablen und insbesondere ansteigenden Produktionsgeschwindigkeit wird der Folienrückhub geschwindigkeitsabhängig angepasst und dazu korrigiert oder verringert.

In summary, in connection with the device described above and its application, there are various possibilities for economical or optimization of production quality serving modes of operation:

• With fast coating production, the Folienrückhub can be turned off because of the high production speeds and the associated very short cycle breaks.
• In the case of pure channel clocking in the area of the cylinder channels, the control of the film return stroke is set to machine-specific fixed angle values, which are controlled as a function of angle and take into account the braking and acceleration ramps as well as the safety clearances.
• In a so-called Sujettaktung the transfer film web of Folienrückhub is variably matched to the circumferential length between edges 83.1, 83.2 of Drucksujets 83 at the Sujetende and Sujetanfang, braking and acceleration ramps and safety distances are to be included.
• In the case of a variable and, in particular, increasing production speed, the film return stroke is adapted as a function of the speed and is corrected or reduced.

If like in FIG. 2 a drive group 33 on the feed side and a drive group 37 of the discharge side of the coating module 2 are provided, the drive group 33 is used on the feed side for the film return stroke. The drive group 37 on the discharge side can be operated in the same work rhythm as the drive group 33, wherein it only has to keep the transfer film web 5 under sufficient tension.

In an alternative control, the drive group 37 can also be switched over during the film return stroke so that there is no active film transport or a continuous transport movement with slippage in relation to the transfer film web 5. Thus, the pressure elements used in each case can be cyclically switched off the film drive roller 70 or reduced in their Anstellwirkung, so that the drive group 33 can perform the Folienrückhub alone.

The very fast clock circuits for the clock drive 71 are derived from an angle signal of the sheet-fed press, wherein the sequences of the control are repeated over each revolution of a counter-pressure cylinder 4 and a press roller 3 respectively. The relevant machine angles for a passage of a cylinder channel 22, 80 for each known printing unit of the sheet-fed printing machine 1, 2, 50 are automatically output from the machine control. For this reason, the relevant machine angles for the timing of the film transport of the transfer film 5 are present in the used as a coating unit 2 printing unit.

As already described alternatives, first the channel timing can be performed with fixed predetermined angle values for braking and acceleration of the transfer film web 5, since the passage angles of the channel edges 81.1, 81.2 are predetermined by the machine construction. For this purpose, the safety switching distances E1, E2 depending on the area coverage of the Drucksujets 83 can optionally be switched on, if, for example, to be coated with metal foil Drucksujet more or less close to the sheet edge.

Furthermore, a Sujettaktung be performed, in which case the angle values for braking and acceleration must be determined. For this purpose, the definition of the area or of the printing format or Drucksujets is required, in which the transfer film web 5 is to move or outside of which the transfer film web 5 can be stopped. This can be made possible in a known manner with the aid of underlayed press covers, cut-out blankets or high-pressure forms prepared as embossing plates.

By manual or metrological determination of the more or less coarse machine angle for the format or Sujetränder to be coated in Drucksujet 83 of a print job then taking into account the braking ramp B and the acceleration ramp C and the safety switching distances E1 and E2, the actual control angle for clock circuits drive groups 33, 37 be easily calculated for the transfer film web 5.

The braking ramp B and the acceleration ramp C can be influenced via control parameters. The mechanical properties of the transfer film 5 play a role, since the thin film is always kept smooth and on the other hand, neither the film itself nor the transfer coating must tear. Usually, standardized values for different types of film are used here, which can be present as a characteristic table in the device.

LIST OF REFERENCE NUMBERS

1

commissioned

2

coating module

3

press roll

4

Impression cylinder

5

Transfer foil / foil web

5A

film feed

5B

foil transfer

6

transfer nip

7

roller drive

8th

Film supply roll

9

Foil composite role

10

Press covering

11

Inking / dampening unit

12

plate cylinder

13

Blanket / blanket cylinder

14

Folienleiteinrichtung

15

Printing plant security

16

dryer

17

Inspection device / monitoring system

18

dancer roll

19

Web tension control

20

Web break monitoring

21

Druckzylinderblasvorrichtung

22

cylinder gap

23

Folienleitwalze

23.1

Folienleitwalze

24

pressure rollers

25

pressure roller

26

Andrucksegment

26.1

inner guide surface

27

holder

28

blow air

29

pressure device

30

stabilizing device

31

Foil guide roller / foil feed

32.1

film storage

32.2

film storage

32.3

Vacuum unit Foil storage

33

drive group

34

drive roller

35

Folienleitwalze

36

Loop / foil loop

37

drive group

38

drive roller

39

Folienleitwalze

40

Impression cylinder

41

Blanket cylinder

42

Blanket / blanket

43

plate cylinder

44

printing plate

45

setting device

46

setting device

50

printing unit

60

nip

70

drive roller

71

clock drive

72

casing

73

Cladding, cladding element

80

cylinder gap

81.1

front channel edge

81.2

rear channel edge

82

Gripper on the impression cylinder 4

83

print motif

83.1

front edge of the printed matter

83.2

rear edge of the printed matter

A1

production speed

A2

Working speed of film return stroke

A3

production speed

B1

Forward delay, deceleration ramp

B2

Backward delay during film return stroke

C1

Reverse acceleration during film return stroke

C2

Forward acceleration, approach ramp

D1

Shifting from forward to reverse

D2

Shifting from reverse to forward

E1

Safety distance to the rear sujetrand

E2

Safety distance to the front sujetrand

G

Cutting drive unit 37

R

transport direction

S

sheet

X

Running speed of the transfer film web during production

Y

Sheet withdrawal speed

Z

Base film savings

Z1

brake loss

Z2

accelerating loss

Claims (8)

1. A device in a sheet-fed printing press for transferring imaging transfer layers from a carrier film to printed sheets at least comprising one applicator unit (1) for an image-wise coating of the printed sheets with an adhesive and comprising a coating mechanism (2) for transferring the transfer layers to the printed sheet in a transfer gap (6) between an impression cylinder (4) and a press roller (3), wherein the transfer film (5), with the transfer layer bearing against the printed sheet, can be guided through the transfer gap (6) together with said printed sheet, and transfer layers are thereby transferred to the printed sheet in an image-wise manner, and comprising a device for feeding the transfer film (5) to the coating mechanism (2), and for discharging from the coating mechanism (2) by means of a drive for moving the transfer film (5) in operating direction, wherein the film advance of the transfer film (5) can be controlled in such a way by means of a device for film guiding that the transport of the transfer film (5) is stopped, when no transfer of a transfer layer onto a printed sheet occurs in the transfer gap (6) of the coating mechanism (2),
   wherein controllable conveying devices for decelerating and accelerating in synchronism with the processing of the film transfer are assigned to the transfer film (5), wherein the conveying devices (33, 37) are embodied to convey the transfer film (5) on a drive roller (34, 70) in a slip-free manner, which guide and drive the film web (5) in a clamped manner and
   that the conveying devices (33, 37) are assigned to a transfer region upstream of the transfer gap (6) or are in each case upstream of or downstream from the transfer gap (6), and that the conveying devices (33, 37) are arranged and embodied to carry out a film return stroke against the production direction (R) of the film transport in response to the film transfer, wherein a conveying device (33, 37) has a film driving roller (34, 38, 70), a highly dynamic timing mechanism (71) coupled thereto, and a contact pressure segment (26), which can be placed against the film driving roller (70) and generates a uniform contact pressure across the length of the film driving roller (70), wherein, when conveying, the transfer film (5) is clamped in a contact-free manner between the film driving roller (34, 38, 70) and the contact pressure segment (26) for the slip-free transport in the region of a gap, and wherein the transfer film (5) is guided around the film driving roller (34, 38, 70) across a wrap angle of at least 90 degrees, wherein the contact pressure segment (26) has a blowing air connection (28), through which blowing air is introduced into a gap between an inner guide surface (26.1) on the contact pressure segment (26) and the film driving roller (34, 38, 70), or the transfer film (5) bearing on said film driving roller.
2. The device according to claim 1,
   characterized in
   that the timing mechanism (71) of the film driving roller (34, 38, 70) can be controlled in such a way that a film return stroke against the production direction (R) of the film transport occurs in response to the film transfer after stopping the film transport in the production direction (R) for the purpose of ending a coating cycle for a printed sheet (S) and prior to starting the film transport in the production direction (R) to begin the coating cycle for the next printed sheet.
3. A method for transferring imaging transfer layers from a carrier film to printed sheets in a sheet-fed printing press at least comprising one applicator unit (1) for an image-wise coating of the printed sheets with an adhesive and comprising a coating mechanism (2) for transferring the transfer layers to the printed sheet in a transfer gap (6) between an impression cylinder (4) and a press roller (3), wherein the transfer film (5), with the transfer layer bearing against the printed sheet, is guided through the transfer gap (6) together with said printed sheet and transfer layers are thereby transferred to the printed sheet in an image-wise manner, wherein the transfer film (5) is fed to the coating mechanism (2) by means of a device for feeding, and is discharged from the coating mechanism (2) by means of a device for discharging, wherein the film feed is carried out by means of a drive for moving the transfer film (5) in the production direction (R), wherein the film advance of the transfer film (5) can be controlled in such a way by means of a device for film guiding that the transport of the transfer film (5) is stopped, when no transfer of a transfer layer onto a printed sheet occurs in the transfer gap (6) of the coating mechanism (2),
   wherein the transfer film (5) is moved by means of controllable conveying devices for decelerating and accelerating in synchronism with the processing of the film transfer, wherein the or all conveying devices (33, 37), which are embodied to guide the transfer film (5) on a drive roller (34, 38, 70) in a slip-free manner, guide and drive the film web (5) in a clamped manner and
   that the transfer film (5) carries out a film return stroke against the production direction (R) of the film transport by means of one or all conveying devices (33, 37), which are assigned to a transfer region upstream of the transfer gap (6) or in each case upstream of or downstream from the transfer gap (6), in a time period, during which no cold film transfer is carried out,
   and that, to carry out the film return stroke, the conveying movement of the transfer film (5) in the production direction (R) is stopped at least by means of the conveying device (33), which is arranged upstream of the transfer gap (6), and the transfer film (5) is then conveyed in a direction of movement against the production direction (R),
   wherein the stopping of the conveying movement of the transfer film (5) occurs by means of the timing mechanism (71) with an adjustable delay along a brake ramp, that the film return stroke is then initiated after a reversal of the direction of rotation of the timing mechanism (71), that the transfer film (5) is moved against the production direction (R) with the largest possible acceleration, that the movement of the transfer film (5) is decelerated against the production direction (R) until the standstill, and that the transfer film (5) is accelerated to the production speed with an adjustable acceleration along an approach ramp in the production direction (R),
   and that the stopping of the movement of the transfer film (5) from the production speed is initiated at least at a safety distance (E) from a rear edge of the printing subject (83) to be printed on the printed sheet (S),
   and that the acceleration of the movement of the transfer film (5) from the standstill to the production speed is initiated ins such a way that the production speed is reached at least at a safety distance (E) from a front edge of the printing subject (83) to be printed on the printed sheet (S).
4. The method according to claim 3,
   characterized in
   that the onset, the duration and the end of the movement of the film return stroke is controlled as a function of the duration of the interruption of the film transfer in such a way that, to determine the process of the film return stroke for determining the onset of the return stroke, a safety distance (E), which is provided on a first printed sheet (S) with respect to the rear edge of the printing subject (83) thereof, in response to ending a production cycle of the film transfer, and/or a brake ramp provided to stop the transfer film (5) for the onset of the film return stroke are determined, and, to determine an end of the return stroke, a brake ramp provided at the onset of a production cycle of the film transfer on a subsequent second printed sheet (S), to reach the production speed of the transfer film (5) from the standstill, and/or a safety distance (E) provided with respect to the front edge of the printing subject (83) thereof, are determined.
5. The method according to one or a plurality of claims 3 to 4,
   characterized in
   that the functions for carrying out the film return stroke of the transfer film (5) are turned off in response to a coating production with production speeds exceeding a threshold value with connected function of the timed movement of the transfer film (5) .
6. The method according to one or a plurality of claims 3 to 4,
   characterized in
   that, in response to exclusively carrying out the timed movement of the transfer film (5) while passing through cylinder channels in the transfer gap (6), the controller of the timing mechanism (71) for carrying out the movement of the film return stroke is adjusted to a fixed movement profile, which is a function of a respective sheet-fed printing press, wherein the movement profile is controlled as a function of a respective angle of rotation of the sheet-fed printing press.
7. The method according to one or a plurality of claims 3 to 4,
   characterized in
   that, in response to carrying out the timed movement of the transfer film (5) with respect to a rear edge running in the transfer gap (8) and/or an approaching front edge of a printing subject (83), the controller of the timing mechanism (71) for carrying out the movement of the film return stroke is controlled in such a way that the film return stroke is variably adapted to the circumferential length between the rear and the front edge of the printing subject (83).
8. The method according to one or a plurality of claims 3 to 4,
   characterized in
   that, in response to a coating production with variable and/or increasing production speeds with connected function of the timed movement of the transfer film (5), the functions for carrying out the film return stroke of the transfer film (5) are adapted or corrected via the controller of the timing mechanism (71) as a function of speed in such a way that the covered distance of the film return stroke is changed and/or increased or decreased.

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