Method of increasing the output of a transfer film upon embossing and apparatus suitable for same

Abstract

There is described a method of increasing the output of a transfer film (1) upon embossing, in particular hot embossing, wherein the transfer film (1) has a carrier film (1a) and a transfer layer portion (1b) which is releasable from the carrier film (1a). During a first embossing operation first regions (10) of the transfer layer portion (1b) which are arranged removed from each other at a spacing a are transferred by means of a first embossing tool from the transfer film (1) onto at least one substrate (2), wherein first openings (10a) are produced at the spacing a in the transfer layer portion (1b) of the transfer film (1). After the first embossing operation the transfer film (1) is wound up after the first embossing operation and fed to at least a further embossing operation.

Claims

1. An apparatus for embossing regions of a transfer layer portion of a transfer film onto a plurality of substrates, the apparatus comprising: a transport unit for transporting the plurality of substrates; a transfer film storage means for providing the transfer film in wound-up form; a transfer film storage means drive motor for regulating drive of the transfer film storage means; an embossing tool comprising an embossing wheel for performing a first and a second embossing operation and to which the transfer film is fed from the transfer film storage means, wherein, during the first embossing operation, first regions of the transfer layer portion, which first regions are arranged removed from each other at a spacing a with respect to one another, are each transferred by means of the embossing tool from the transfer film onto a respective one of first substrates of the plurality of substrates, and wherein the transferred first regions leave first openings from which they are transferred at the spacing a in the transfer layer portion of the transfer film; an embossing wheel drive for regulating drive of the embossing wheel, the embossing wheel drive comprising a servomotor or an operatively driving coupling to a drive of the transport unit; a transfer film take-up means onto which the transfer film inclusive of the first openings is wound after the first embossing operation; and a transfer film take-up means drive motor for regulating drive of the transfer film take-up means, wherein, arranged between the embossing tool and the transfer film take-up means is a first sensor unit which by means of at least one first sensor of the first sensor unit detects a position of the first openings in the transfer layer portion of the transfer film prior to the transfer film being wound onto the transfer film take-up means after the first embossing operation, the at least one first sensor of the first sensor unit producing first control data based on the detected position of the first openings, wherein, arranged between the transfer film storage means and the embossing tool is a second sensor unit comprising a first sensor, a second sensor, and a third sensor, wherein as part of the second embossing operation, the first and second sensors of the second sensor unit detect the position of the first openings and the third sensor of the second sensor unit detects position of remaining transferable second regions which are each respectively arranged between two of the first openings in the transfer layer portion of the transfer film prior to each of the remaining second regions being transferred by means of the embossing tool to a respective one of further substrates of the plurality of substrates in the second embossing operation, the second sensor unit producing second control data based on the detected position of the first openings and the position of the second regions, and wherein the first and second control data are used to regulate a speed of each of the transport unit, the transfer film storage means drive motor, the embossing wheel drive, and the transfer film take-up means drive motor during the first and second embossing operations, respectively.

2. An apparatus as set forth in claim 1, wherein the transfer film storage means comprises a first film cartridge and the transfer film take-up means comprises a second film cartridge, and wherein each of the first and second film cartridges include an annular core and two cover plates so that for each of the first and second film cartridges, the transfer film can be wound around the core and can be laterally constricted by a respective one of the two cover plates.

3. An apparatus as set forth in claim 2, wherein the transfer film storage means drive motor unwinds the transfer film from the first film cartridge and the transfer film take-up means drive motor winds the transfer film onto the second film cartridge.

4. An apparatus as set forth in claim 2, wherein the first and second film cartridges are interchangeable between the transfer film storage means and the transfer film take-up means.

5. An apparatus as set forth in claim 1, wherein there is arranged between the embossing tool and the transfer film take-up means a first transfer film tensioning device for keeping tension of the transfer film constant in the region between the embossing tool and the transfer film take-up means.

6. An apparatus as set forth in claim 5, wherein there is arranged between the transfer film storage means and the second sensor unit a second transfer film tensioning device for keeping tension of the transfer film constant in the region between the transfer film storage means and the embossing tool.

7. An apparatus as set forth in claim 6, wherein the first transfer film tensioning device includes a first tensioning or dancer roller and a position of the first tensioning or dancer roller is pneumatically variable.

8. An apparatus as set forth in claim 7, wherein the second transfer film tensioning device includes a second tensioning or dancer roller and a position of the second tensioning roller is pneumatically variable.

9. An apparatus as set forth in claim 6, further comprising a control unit for controlling the position of the first and/or second tensioning or dancer rollers.

10. An apparatus as set forth in claim 1, wherein during the first embossing operation, a sequence of movements of the embossing tool and/or of the transfer film and/or of the transport unit for transporting the first substrates of the plurality of substrates is regulatable using the first control data.

11. An apparatus as set forth in claim 10, wherein the sequence of movements influence a spatial position of the embossing tool and/or of the transfer film and/or of the transport unit.

12. An apparatus as set forth in claim 1, wherein during the second embossing operation, a sequence of movements of the embossing tool and/or of the transfer film and/or of the transport unit for transporting second substrates of the plurality of substrates is regulatable using the second control data.

13. An apparatus as set forth in claim 12, wherein the sequence of movements influence a spatial position of the embossing tool and/or of the transfer film and/or the transport unit.

14. An apparatus as set forth in claim 1, wherein each of the sensors of the first sensor unit and/or the second sensor unit is an optical sensor.

15. An apparatus as set forth in claim 1, wherein the embossing wheel drive is a servomotor.

16. An apparatus as set forth in claim 1, wherein the transfer film comprises the transfer layer portion and a carrier film from which the transfer layer portion is releasable for the first and second embossing operations.

17. An apparatus as set forth in claim 1, wherein each of the first and second substrates of the plurality of substrates are consecutively disposed, one after the other each receiving a respective one of the first and second transfer regions during the first and second embossing operations, respectively.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1 through 5 are intended to describe by way of example the method according to the invention and the apparatus according to the invention by reference to a card embossing method. In the drawing:

(2) FIG. 1 diagrammatically shows a transfer film in the first embossing operation,

(3) FIG. 2 shows the transfer film of FIG. 1 in a further embossing operation,

(4) FIG. 3a shows the transfer film after the two embossing operations of FIGS. 1 and 2,

(5) FIG. 3b shows the further substrates 2 after the further embossing operation,

(6) FIG. 4 shows a diagrammatic side view of an apparatus for performing the method steps performed in FIGS. 1 and 2, and

(7) FIG. 5 shows a portion W from the apparatus of FIG. 4 in the region of the second sensor unit.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1 diagrammatically shows a transfer film 1 in the first embossing operation in which substrates 2 in the form of cards are to be embossed upon. The substrates 2 are arranged in succession in a row. Arranged above the substrates 2 is a transfer film 1 in band form, which has a carrier film 1a and a transfer layer portion 1b which is not visible in this view (see FIG. 3a) on the side of the carrier film 1a, that is towards the substrates 2. In the first regions 10, the position of which on the transfer film 1 is indicated here by solid rectangular line the transfer layer portion 1b is embossed onto the substrates 2, in which case the first regions 10 are respectively disposed on the transfer film 1 spaced from each other at the constant spacing a. In the operation of embossing the first regions 10 out of the transfer layer portion 1b onto the substrates 2, a respective first opening 10a is produced in the transfer layer portion 1b of the transfer film 1 (see FIGS. 2 and 3a). After the first embossing operation the transfer film 1 is wound up in a uniform, regulated fashion.

(9) FIG. 2 now diagrammatically shows the transfer film 1 of FIG. 1 in the second embossing operation in which further substrates 2 in the form of cards are to be embossed upon. The substrates 2 are arranged in succession in a row. Disposed above the substrates 2 is the transfer film 1 which in the form of a band and which has the carrier film 1a and the transfer layer portion 1b which is not visible in this view (see FIG. 3a), on the side of the carrier film 1a that is towards the substrates 2. The transfer layer portion 1b is embossed onto the substrates 2 in the second regions 11, the position of which on the transfer film 1 is indicated here by broken rectangular line, the second regions 11 being disposed between the first openings 10a produced in the first embossing operation in the transfer layer portion 1b on the transfer film 1. The position of the first openings 10a in the transfer layer portion 1b of the transfer film 1 is indicated in this view by hatched areas.

(10) In the operation of embossing the second regions 11 onto the substrates 2, second openings 11a are produced in the transfer layer portion 1b of the transfer film 1 (see FIG. 3a).

(11) FIG. 3a shows the transfer film 1 after the first and further embossing operations viewed from the side in FIGS. 1 and 2, on which the transfer layer portion 1b is disposed. The transfer layer portion 1b has first openings 10a which were formed during the first embossing operation and also second openings 11a which were formed during the further embossing operation. The first openings 10a and the second openings 11a give a free view onto the carrier film 1a.

(12) FIG. 3b shows the further substrates 2 which as shown in FIG. 2 were embossed upon with the second regions 11 of the transfer layer portion 1b of the transfer film 1 after removal of the transfer film 1.

(13) FIG. 4 shows an apparatus for carrying out the method steps performed in accordance with FIGS. 1 and 2, as a diagrammatic side view. The transfer film 1 is provided by way of a transfer film storage means 3 in the form of a first film cartridge driven in rotation by means of a motor, wherein the transfer film 1 is wound onto the core 3b of the first film cartridge, the core 3b being disposed between the cover plates 4a, and is fed to the second sensor unit 8 by way of a second transfer film tensioning device which includes a second dancer roller 9b and which keeps the transfer film tension constant. After the second sensor unit 8 the transfer film 1 passes to a pulling mechanism 14 driven by means of a servomotor, and to the contact pressure roller 15.

(14) From there the transfer film 1 is fed to an embossing tool 5 in the form of a segmented embossing wheel, the contact pressure force of which in relation to a counterpressure or backing roller 6 can be regulated by way of an embossing cylinder 13 involving stroke adjustment. The transfer film 1 and the substrates 2 (not shown here) are conveyed through between the embossing tool 5 and the counterpressure roller 6 for carrying out the first embossing operation. The embossing tool 5 is heatable by means of a heating hood 16. Segment adjustment 17 serves for adjusting the position of the area to be embossed on a substrate in the longitudinal direction thereof. The first regions 10 of the transfer layer portion 1b of the transfer film (see FIGS. 1 through 3) are fixed to a respective one of the substrates 2 by means of the embossing tool 5 during a first passage of the transfer film 1 through the apparatus. Downstream of the embossing tool 5 the composite assembly comprising the substrate 2 and the transfer film 1 is fed jointly to a cooling device 12 and then the transfer film 1 is pulled off the embossed substrate 2. A first region 10 of the transfer layer portion 1b remains fixed to each substrate 2. The transfer film 1 inclusive of the first openings 10a is now fed to the transfer film take-up means 4 in the form of a second film cartridge driven in rotation by means of a motor, by way of a first sensor unit 7 and a first transfer film tensioning device which includes a dancer roller 9a and which keeps the transfer film tension constant, and is wound onto the core 4b of the second film cartridge which is between the cover plates 4a. During the first embossing operation the first sensor unit 7 by means of an optical sensor detects the position of the first openings 10a in the transfer layer portion 1b of the transfer film 1 and produces first control data, by means of which a sequence of movements of the embossing tool 5 and/or the transfer film 1 and/or a transport unit which is not shown here, for example in the form of a transport chain, for transporting the substrates 2 is regulated in such a way that the spacing a between the first openings 10a remains constant or at least substantially constant. After the second embossing operation is performed the second film cartridge of the transfer film take-up means 4 inclusive of the transfer film 1 which now has the first openings 10a is exchanged with the empty first film cartridge of the transfer film storage means 3 and a renewed run of the transfer film 1 through the apparatus is started for performing a further embossing operation. Now, in the region of the second sensor unit 8, the position of the first openings 10a is detected by means of optical sensors 8a, 8b and the position of the second regions 11 of the transfer layer portion 1b, which are to be respectively stamped out between two adjacent first openings 10a, is ascertained by means of a third optical sensor 8c (see FIG. 5). Accordingly, during the second embossing operation, the second sensor unit 8 by means of three optical sensors detects the position of the first openings 10a in the transfer layer portion 1b of the transfer film 1 and regulates the sequence of movements of the embossing tool 5 and/or the transfer film 1 and/or the transport unit which is not shown here, for example in the form of a transport chain, for transportation of the further substrates 2 in such a way that the first openings 10a do not overlap with the second regions 11 and a spacing a is maintained between each first opening 10a and a second region 11 of at least 0.5 mm. After the second regions 11 are stamped out onto the further substrates 2 by the embossing tool 5, that is followed by cooling and separation of the transfer film and the further substrates 2, as already described in relation to the first embossing operation. The transfer film 1 which now has the first openings 10a and the second openings 11a is wound onto the film cartridge of the transfer film take-up means 4.

(15) The following settings for embossing of the card-form substrates 2, 2 are used for example:

(16) TABLE-US-00001 Process speed 25000 card-form substrates 2, 2 per hour Length of a card-form substrates 2, 2 85.6 mm Chain pitch of the transport chain for 88.9 mm transporting the substrates 2, 2 Width of the transfer film 10 mm Dimensions of the first/second regions 8 mm 35 mm Area of the first/second regions 280 mm.sup.2 Transfer film consumption per hour 22225 m.sup.2 Transfer film consumption per substrate 2 889 mm.sup.2 when carrying out only a first embossing operation Degree of use of the transfer film in only 31.49% one embossing operation Transfer film consumption per substrate 2 444.5 mm.sup.2 when carrying out a further embossing operation Degree of use of the transfer film in two 63% embossing operations

(17) The costs of the transfer film are reduced accordingly by 41% by virtue of the double use of the transfer film for carrying out a first and a further embossing operation.

(18) FIG. 5 shows the portion W of the FIG. 4 apparatus, in which the second sensor device 8 is disposed, but without the transfer film 1. The transfer film 1 which already has the first openings 10a in the transfer layer portion 1b of the transfer film 1 is shown to the right beside the second sensor unit 8, to better illustrate the mode of operation thereof. The second sensor unit 8 has three optical sensors 8a, 8b, 8c, wherein the two sensors 8a and 8b detect the position of the first openings 10a in the transfer layer portion 1b of the transfer film 1 during the second embossing operation. The sensor 8c serves to determine the position of the second region 11 which is still to be stamped out. The three sensors 8a, 8b, 8c form second control data which are used to regulate the movements of the embossing tool 5 and/or the transfer film 1 and/or a transport unit for transporting the further substrates 2, in such a way that the first openings 10a do not overlap with the second regions 11 and a spacing is maintained between first opening 10a and a second region 11 of at least 0.5 mm.

(19) It will be appreciated that the method according to the invention can be used not only for embossing card-form substrates, but it is suitable for all embossing procedures in which a transfer film was only inadequately used after the first embossing operation and sufficiently large regions of the transfer layer portion have remained on the carrier film to be able to carry out a further embossing operation with the transfer film which has already been used.

LIST OF REFERENCES

(20) 1 transfer film 1a carrier film of the transfer film 1b transfer layer portion of the transfer film 2 substrate in card form 2 further substrate in card form 10 first regions of the transfer layer portion 10a first openings in the transfer layer portion 11 second regions of transfer layer portion 11a second openings in the transfer layer portion 3 transfer film storage means in the form of a first film cartridge 3a cover plates of the first film cartridge 3b core of the first film cartridge 4 transfer film take-up means in the form of a second film cartridge 4a cover plates of the second film cartridge 4b core of the second film cartridge 5 embossing tool 6 counterpressure roller 7 first sensor unit 8 second sensor unit 8a, 8b, 8c sensors of the second sensor unit 9a first dancer roller of the first transfer film tensioning device 9b second dancer roller of the second transfer film tensioning device 12 cooling device 13 embossing cylinder with stroke adjustment 14 pulling mechanism with servomotor drive 15 contact pressure roller 16 heating hood 17 segment adjustment