STAMPING FOIL UNIT
To transfer a coating in image form from a transfer foil to a print sheet, adhesive is applied in the form of the image to said sheet. In a foil transfer module ( 2 ), the carrier foil with the coating in image form is then brought into contact with the print sheet using contact pressure, so that the coating adheres to the adhesive pints and an image is produced. To improve the function, simplify the device and increase the flexibility of the method, a transfer cylinder ( 3 ) is provided with a covering that has a variable cover thickness ( 25 ), in order to adapt the surface speed of the transfer cylinder ( 3 ).
1 - 15 . (canceled)
16 . A device for transferring an image-forming layer from a carrier foil of a transfer foil onto a printing sheet, comprising:
an application unit for applying an adhesive to areas of the printing sheet; and
a foil transfer module for transferring the image-forming layer from the carrier foil onto the printing sheet, the foil transfer module including an impression cylinder and a transfer cylinder that form a transfer nip;
the device being configured to guide the carrier foil relative to the transfer cylinder such that the carrier foil is placed with a coated side onto a printing sheet guided on the impression cylinder and to further guide the carrier foil under pressure together with the printing sheet through the transfer nip such that the image-forming layer adheres to the printing sheet in the areas furnished with adhesive and is lifted off the carrier foil after the printing sheet exits transfer nip;
the transfer cylinder having a surface with a covering, the transfer cylinder and covering defining an active surface of the transfer cylinder, the transfer cylinder with the covering being driveable at a speed at the active surface of the transfer cylinder that is up to 3% above a surface velocity of the impression cylinder with the printed sheet and the transfer foil lying thereon.
17 . The device according to claim 16 , wherein the covering on the surface of the transfer cylinder has a variable packing thickness.
18 . The device according to claim 17 , wherein the covering on the surface of transfer cylinder comprises a pressing cover and at least one underlayer.
19 . The device according to claim 17 , wherein the covering on the surface of transfer cylinder has a variable packing thickness that provides an effective diameter of the transfer cylinder of up to 0.9 mm greater than its nominal diameter with a normal packing thickness.
20 . The device according to claim 16 , wherein the covering on the transfer cylinder has a low compressibility and has minimal adhesion to the carrier foil.
21 . The device according to claim 16 , wherein the covering has a functional layer comprising a low surface tension layer and the covering has a compressible substructure.
22 . The device according to claim 16 , wherein the covering is detachably clamped onto the transfer cylinder and covers the entire surface of the transfer cylinder.
23 . The device according to claim 16 , further including a remotely adjustable device for varying a center distance of the transfer cylinder from the impression cylinder.
24 . The device according to claim 16 , further including a drive for the transfer cylinder, the drive being configured such that the speed of the active surface of transfer cylinder relative to the surface velocity of the impression cylinder can be varied.
25 . The device according to claim 24 , further including a continuously variable transmission operatively coupled to the transfer cylinder.
26 . The device according to claim 24 , wherein the drive comprises a drive motor with a continuously adjustable drive speed.
27 . The device according to claim 24 , further including a regulating mechanism for variably adjusting the speed of the active surface of transfer cylinder relative to the surface velocity of the impression cylinder as a function of an operating speed of the device.
28 . The device according to claim 24 , further including a regulating mechanism for variably adjusting the speed of the active surface of transfer cylinder relative to the surface velocity of the impression cylinder as a function of a web tension on the transfer foil.
29 . The device according to claim 24 , further including a regulating mechanism for variably adjusting the speed of the active surface of transfer cylinder relative to the surface velocity of the impression cylinder as a function of a contact pressure between the transfer cylinder and the impression cylinder including the thickness of the covering on the transfer cylinder.
30 . The device according to claim 24 , further including a regulating mechanism for variably adjusting the speed of the active surface of transfer cylinder relative to the surface velocity of the impression cylinder as a function of a temperature difference occurring in the foil transfer module.