DE102008000743B4 - Film guide in a cold foil unit - Google Patents

Abstract

Device for transferring image-forming layers from a transfer film (5, 5 ') to a printing sheet provided with an image-wise coating with an adhesive with a coating unit (2) which has a counter-pressure cylinder (4) forming a common transfer nip (6, 6') and a Press roll (3), wherein the transfer sheet (5) of a film supply roll (8) around the press roll (3, 3 ') or approximately tangentially to the press roll (3, 3') is feasible, such that they are coated with the Side on the on the impression cylinder (4) guided print sheet resting and under pressure for transferring the coating together with the sheet through the transfer nip (6, 6 ') is guided, wherein the so used transfer film (5) after leaving the transfer nip ( 6) is fed to a film collecting device, in that guide devices (30, 31, 32) for guiding the transfer film (5, 5 ') from the film supply roll (8) to the transfer nip (6, 6') of the web of the transfer film (5, 5 ') are assigned to prevent lateral movements, and that the guide means ...

Description

The invention relates to a film guide in the transfer of imaging layers of a carrier film on with an imagewise coating provided with an adhesive sheet 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. So is in the EP 0 569 520 B1 a printing material and a printing apparatus using this material are described. In this case, a sheet-processing machine is shown, which has a feeder and a boom, between two units printing units and a coating unit are arranged. In at least one of the printing units, an adhesive pattern is applied by 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 unit 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 passed through the transfer nip of the coating unit between the impression cylinder and the press roll from a film supply roll. The foil strip is rewound on the outlet side after leaving the coating unit. 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 unit, being brought by means of the press roller on the impression cylinder resting sheet with the film material in combination. In this case, the downwardly lying metallic layer enters into a close connection with the areas provided with adhesive on the printed sheet. After further transporting the printing sheet, the metallic layer adheres only in the area provided with the adhesive pattern. The carrier film is thus removed from the metallic layer in the region of the adhesive pattern. The used in this way transfer film is wound up again. The print sheet is laid out in the coated state.

It is known to use such coating units, for example in printing units of printing presses. A disadvantage of the known devices is that they are not flexible and that the supply of the transfer film is difficult to handle.

From the DE 10 2005 037 496 A1 a monitoring device of a film guide is known. In this case, sensors are arranged in the region of deflections of a film web on rollers or on the bearings of such rollers, by means of which a presence or absence of the film web can be detected directly or indirectly.

From the DE 10 2005 011 568 A1 a production method for an embossing device in a sheet-fed press is known. In this case, a film web guide is shown in a coating unit having guide elements of various types. The transfer film web is guided freely stretched on the transport path from the film supply roll to the transfer nip in front of the coating unit.

From the WO 2005/049322 A1 For example, a method and apparatus for combination pressure is known. The device has tension rollers and spreader rollers, by means of which the film carrier web is spread smoothly and can be smoothly introduced into the transfer nip. The film web guide has no freely stretched areas.

In relation to the strains of the film webs, which vary depending on the web speed, the take-up quality of the film roll, and changes in web tension, the film web tends to move irregularly as it runs off the film roll. Particularly as a result of variables of the application nozzle and a so-called channel excitation, the film web tends to oscillate more or less strongly, so that the film web begins to perform a striking movement transversely to the conveying direction in the freely guided region.

Although known systems with so-called dancer rollers have a dampening effect on the web tension, the film web which has been vibrationally resonant, ie. H. their striking transverse movement, not always sufficiently calm.

As a result of the beating or fluttering of the film web, quality problems due to wrinkling in the film web and, moreover, errors in the film application can occur in the application process.

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

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

In an advantageous manner, a feed device is used to guide the transfer film, in which the transfer film is monitored by sensors during the feed to the transfer nip and the discharge to the transfer nip.

An associated apparatus for supplying and discharging the transfer film advantageously has a guide device in the form of guide rollers, by means of which the supply to the transfer nip and the discharge to the transfer nip are made possible in a simple manner.

To stabilize the film web, a stabilizing device is arranged between a first deflection roller or the unwinding roller and a first inlet roller or guide for the film web to the transfer nip. This achieves an efficient reduction of the striking movement of the film web. This is done in a very simple way, since the stabilizing device can be attached to the outside of the printing unit acting as a coating unit.

The stabilization device has z. B. two rotatably mounted guide rollers, which form an S-shaped deflection for the film web and are arranged eccentrically adjustable in their suspension.

At least one of the two guide rollers can be designed here as a spreader roller. Thus, the film web is stretched in its plane transverse to the direction and kept smooth, which in turn contributes to reducing harmful to the process wrinkling.

To influence or regulate the position of the film web in the width direction or transversely to the direction of rotation, an inclined position of the guide rollers can be provided, for example, via a bearing on eccentrically adjustable bearing elements, so that a guide roller pair is formed.

Finally, in connection with the storage of the guide roller pair, the arrangement of a pivot bearing for changeable adjustment of the wrap angle of the film web may be provided on the guide rollers. In this way, the guiding action and the damping effect of the guide rollers on the film web can be sensitively adjusted depending on the operating state.

Also for web break monitoring for the film web, the guide rollers can be mounted on sensor-equipped pickup elements, so that the pivot position or axle load of the guide rollers can be detected.

A surface coating of the guide rolls contributes to the safe prevention of film deposits on the surface and reduces the risk of retransmission of these deposits in unwanted areas of the same or another web. Furthermore, the surface coating also avoids damage to the transfer layer on the film web, which could render it useless.

All of the above adjusting elements on the described guide rollers or their suspensions can optionally be controllably arranged via electrical, pneumatic, hydraulic actuators.

The stabilization device described can also be used on the film outlet side in the same way. In this way, a reduction of wrinkles which retrogresses from the drainage area into the application gap can be achieved in the coating module and the coating quality can be increased.

Web tear detection of the film web can be carried out by means of an ultrasonic sensor system by direct scanning of the film web in a freely guided section.

The web tear detection can also be done with capacitive sensors by direct scanning against elements that lead the film web touching. These can be rotating guide rollers or stationary guide surfaces.

The web tear monitoring can also be carried out independently of the guide rollers and indirectly via a web tension measuring device, wherein by measuring radially directed bearing forces of a measuring roller, which is wrapped by the web or coating film, the presence of the film web can be detected. A measuring amplifier evaluates the electrical signals. If the web tension forces during operation deviate from predetermined values by falling below a minimum value or exceeding a maximum value, this is evaluated as a crack or overloading of the film and fed to the machine control. Possible installation locations for the measuring device are on the roll-up device or on the unwinding device of the film web, in the region of film guide rolls or on dancer rolls.

The device can be used in an advantageous manner if an improvement in film utilization is to be achieved by dividing the transfer film into one or more partial film webs of lesser width. In combination with The above method can be used side by side so also different types of films.

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

Showing:

1 : An overview of a printing press with a film transfer device and

2 and 3 : The structure of inventive devices for film control.

In 1 a sheet-processing printing machine is shown, which consists of at least two printing units. The two printing units are used for the following purposes:
A printing sheet is provided in the first printing unit with an imaging adhesive pattern (Auftragwerk 1 ).

Thereafter, in the next printing unit, together with a printing sheet, a transfer film 5 through a transfer gap 6 guided, with the transfer film 5 in the transfer gap 6 pressed against the sheet (coating 2 ).

The commissioned work 1 can be a well-known offset printing unit with an inking unit 11 , a plate cylinder 12 , a blanket cylinder 13 and a sheet leading impression cylinder 4 be. Likewise, this may be a so-called paint module in which the blanket cylinder 13 is designed as a paint form cylinder. The paint cylinder is with color or glue from a z. B. trained as a chamber doctor blade device instead of the inking unit 11 provided.

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

The transfer foils 5 are multi-layered. They have a carrier layer on which an imaging layer is applied by means of a release layer. The separating layer serves to facilitate lifting of the imaging layer from the carrier layer. The imaging layer may, for. Example, a metallized layer or a glossy layer or a textured layer or a colored layer or a pattern containing one or more image patterns.

The foil supply roll 8th is the coating plant 2 assigned on the side of the sheet feeder. The foil supply roll 8th has a rotary drive 7 on. The rotary drive 7 is used for continuous controlled feeding of the transfer film to the coating unit 2 needed and is therefore controllable. Furthermore, a deflecting or tensioning roller is provided in the region of the film feed. Thus, the film web of the transfer film is always in the same voltage relative to the press roller 3 held. On the downstream side of the printing unit is a film collecting roll 9 shown. On the foil collecting roll 9 the used foil material is rewound. Here, too, is a rotary drive for the optimized production 7 provide that is controllable. In essence, the transfer film could 5 also by the rotary drive 7 moved on the drain side and kept taut on the inlet side by means of a brake.

The transfer process of the imaging z. B. metallized layer on the printing paper takes place in the transfer nip 6 between the press roll 3 and the impression cylinder 4 ,

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

The press roll 3 is with a press cover 10 z. B. as a plastic coating, comparable to a blanket or blanket, provided. The press fabric 10 is held in a cylinder channel on jigs.

To ensure the economy of the coating process is provided that the film feed the transfer film 5 from the film supply roll 8th to the transfer gap 6 and to the foil collecting roll 9 is controllable so that as far as possible the transfer film 5 is then stopped if no transmission of the imaging layer is to take place. For this purpose, a control of the transfer film 5 done so that during the passage of a gripper of the sheet leading impression cylinder 4 receiving cylinder channel of the film feed is stopped.

An improved film utilization results from the fact that the transfer film 5 in one or several Teilfolienbahnen smaller width is divided. Within the coating plant used for the film transfer 2 is a web guide for transfer films 5 represented, the film guide rollers 14 by means of which the transfer film 5 the transfer gap 6 is fed and removed from this. In this case, according to the film guide arranged openings in at the coating plant 2 existing print protection 15 provided. These openings are designed so that the film webs 5 easily accessible and dissipatable and at the same time the protective function is fully retained.

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

In 1 three variants of the web guide are shown:

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

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

In an embodiment according to the invention according to the 2 and 3 and therefore can transport the transfer film 5 on or between film guide rollers 14 by means of metrological control of the web tension of the film web 5 be monitored.

In a film web guide to one or more web tension measuring devices 23 . 25 provided, the force measuring devices have. The principle is based on the measurement of radially directed bearing forces of a guide roll substantially in the direction of the bisecting line to the take-off directions of the film web wrapping around it 5 , In this case, the film tear or web break detection can take place with a significant drop in the measured force below a defined threshold value.

A web tension measuring device 23 can according to 2 on a film deflecting roller 14 the web guide of the film web 5 be arranged. In this case, the reaction force of the film web 5 on the storage of Folienumlenkwalze 14 preferably at an angle of 45 degrees, ie substantially in the direction of the bisector on the inside to the right-angled deflection of the film web 5 determined.

A web tension measuring device 25 can according to 3 also on a separate measuring roller 24 in conjunction with the web guide of the film web 5 be arranged. In this case, the reaction force of the film web 5 on the storage of the measuring roller 24 preferably at an angle according to the bisector on the inside of the deflecting web guide of the film web 5 determined. This complicates the storage of Folienumlenk- or guide rollers 14 avoided.

To stabilize the film web 5 will, as in 1 shown between a pulley 20 and a film guide roll 14 a stabilizer 30 arranged. The stabilizer 30 is preferably approximately in the middle of the distance between the adjacent film guide elements (here deflection roller 20 and film guide roll 14 ) arranged. This is the area between the structure of the Folienrollollung on the coating plant 2 and the film feed to the transfer nip 6 in the coating plant 2 to be bridged.

With this arrangement, an efficient reduction of the beating movement or flutter movement of the film web 5 reached.

The stabilizer 30 has z. B. two rotatably mounted guide rollers 31 . 32 on, as a guide roller pair on a pivotable and possibly eccentrically adjustable with respect to their alignment axis storage device 33 are arranged.

At least one of the two guide rollers 31 . 32 can be executed here as a spreader roll. This is the film web 5 stretched in their plane transverse to the direction of rotation and kept smooth, which in turn contributes to reducing harmful to the process of wrinkling.

For regulating or adjusting the position of the film web 5 in the width direction, an inclination of the guide rollers 31 . 32 for example, about the said storage on eccentrically adjustable storage facilities 33 be provided.

Finally, the arrangement of a pivot bearing 34 for changeable adjustment of the wrap angle of the film web 5 at the guide rollers 31 . 32 be provided so that the guiding action and the damping effect of the guide rollers 31 . 32 on the film web 5 is adjustable depending on the operating state. By pivoting the wrap of the film web 5 at the guide rollers 31 . 32 and thus their areal edition increased or decreased.

The adjustment and operation of the stabilizer 30 can be used in conjunction with a web tension control and if necessary with a device for web break monitoring (for both see Sensor 25 ).

• 1. Ein Bahnzug (Bahnspannung) oberhalb eines vorgebbaren Minimalwerts wird als Signal für das Vorhandensein der Folienbahn 5 gewertet und dieses wird der Maschinensteuerung zugeführt.
• 2. Ein Überschreiten des Maximalwerts des vorgebbaren Bahnzugs (Bahnspannung) wird über Tänzerwalzen 18 oder die Drehantriebe 7 der Folienvorratsrolle 8 bzw. Foliensammelrolle 9 reduziert. Damit kann eine unzulässige Dehnung oder ein Riss der Folienbahn 5 vermieden werden.
• 3. Ein Unterschreiten des Minimalwerts des vorgebbaren Bahnzugs (Bahnspannung) wird überprüft, indem abgefragt wird, ob die Bahnspannungsregelung noch aktiv ist. Ebenso kann über Tänzerwalzen 18 oder eine Bremse die Bahnspannung wieder erhöht werden. Ist dies nicht möglich wird ein Bahnriss erkannt.

Electrical signals of the web tension measuring devices 23 . 25 are evaluated. Various operating states are possible for this:

• 1. A web tension (web tension) above a predeterminable minimum value is used as a signal for the presence of the film web 5 evaluated and this is fed to the machine control.
• 2. Exceeding the maximum value of the predeterminable web tension (web tension) is achieved by dancer rolls 18 or the rotary actuators 7 the film supply roll 8th or film collecting roll 9 reduced. This can be an impermissible strain or a crack of the film web 5 be avoided.
• 3. A drop below the minimum value of the predeterminable web tension (web tension) is checked by asking whether the web tension control is still active. Likewise can over dancer rolls 18 or a brake, the web tension can be increased again. If this is not possible, a web break will be detected.

The additionally obtained information about the web tension as the actual value, in particular in the context of the aforementioned evaluations, can be used for the control of the printing or transfer process. For this purpose, the system can be coupled to a control station of the printing press. The setpoints for maximum and minimum web tension (web tension) can be entered via the control station. These values may vary depending on the type of transfer film used 5 and the pressure or transfer conditions in the coating module 2 be dependent on 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 by means of parameter values from the setting of the transfer process on the coating module 2 to be changed.

LIST OF REFERENCE NUMBERS

1

commissioned

2

coating plant

3

Press roller ( 3 ' )

4

Impression cylinder

5

Transfer foil / foil web ( 5 ' )

6

Transfer gap ( 6 ' )

7

rotary drive

8th

Film supply roll

9

Foil composite role

10

Press covering

11

inking

12

plate cylinder

13

Blanket cylinder

14

Folienumlenk - / - guide roll

15

Printing plant security

18

dancer roll

20

idler pulley

23

Web tension measuring device

24

measuring roll

25

Web tension measuring device

30

stabilizing device

31

guide roll

32

guide roll

33

storage facility

34

pivot bearing

Claims (3)

Device for transferring image-forming layers from a transfer film ( 5 . 5 ' ) coated with an image-wise coating with an adhesive sheet with a coating unit ( 2 ), which has a common transfer gap ( 6 . 6 ' ) forming impression cylinder ( 4 ) and a press roll ( 3 ), wherein the transfer film ( 5 ) from a film supply roll ( 8th ) around the press roll ( 3 . 3 ' ) or approximately tangentially to the press roller ( 3 . 3 ' ) is feasible, such that it with the coated side on the on the impression cylinder ( 4 ) guided print sheet lying on and under pressure for transferring the coating together with the sheet through the transfer nip ( 6 . 6 ' ), whereby the so used transfer film ( 5 ) after exiting the transfer gap ( 6 ) is fed to a film collecting device, that guide devices ( 30 ; 31 . 32 ) for guiding the transfer film ( 5 . 5 ' ) from the film supply roll ( 8th ) to the transfer gap ( 6 . 6 ' ) of the web of the transfer film ( 5 . 5 ' ) are assigned to prevent lateral movements, and that the guide devices ( 30 . 31 . 32 ) and / or regulation of the web tension of the web of the transfer film ( 5 . 5 ' ) are assigned adjustable characterized in that a stabilizer device ( 30 ) in conjunction with several rotating Folienumlenk- or guide rollers ( 31 . 32 ) for guiding the film web ( 5 . 5 ' ) under the action of force on the freely stretched film web ( 5 . 5 ' ) and that the rotating Folienumlenk- or guide rollers ( 31 . 32 ) in pairs or several times on each end of a common storage device ( 33 ) of a pivot bearing ( 34 ) are arranged such that these in the leadership of the film web ( 5 . 5 ' ) for increasing or decreasing the looping at the Folienumlenk- or guide rollers ( 31 . 32 ) by means of the pivot bearing ( 34 ) parallel to the axes of Folienumlenk- or guide rollers ( 31 . 32 ) are pivotally provided. Apparatus according to claim 1, characterized in that at least one of the rotating Folienumlenk- or guide rollers ( 31 . 32 ) as a spreader roll for smooth guidance of the film web ( 5 . 5 ' ) is provided. Device according to one of the preceding claims, characterized in that the rotating Folienumlenk- or guide rollers ( 31 . 32 ) in pairs or several times on each end of a common storage device ( 33 ) are arranged and that they are used to control the web guiding direction in the guidance of the film web ( 5 . 5 ' ) are provided pivotable relative to an axis parallel to the roll axes tilted.

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