Claims
- 1. An offset printing system having the capability to print variable-sized images on at least a first side of a traveling web, said system comprising:a) at least one ink source; b) at least one plate cylinder having a replaceable sleeve, said replaceable sleeve adapted to have mounted thereon a printing plate, said printing plate adapted to receive ink from said ink source; c) at least one blanket cylinder; d) at least one image transfer belt having a surface positioned to contact both said printing plate, in a first nip formed between said plate and blanket cylinders, and the first side of the traveling web in a second nip formed between said blanket cylinder and an impression cylinder; e) at least one image transfer belt tensioning system to register said image transfer belt to said blanket cylinder position in the area of said first and second nips for desired image transfer; and f) at least one image belt cleaning station adapted to remove residual ink from said surface of said image transfer belt.
- 2. An offset printing system as claimed in claim 1 in which said belt tensioning system comprises a plurality of tensioning rolls about which said image transfer belt is driven.
- 3. An offset printing system as claimed in claim 2 in which at least one of said tensioning rolls is temperature controlled.
- 4. An offset printing system as claimed in claim 1 including a sensing device for sensing the position of said image transfer belt.
- 5. An offset printing system as claimed in claim 1 in which said image transfer belt comprises at least one base ply, at least one layer of a compressible material over said base ply, and a surface ply over said layer of compressible material.
- 6. An offset printing system as claimed in claim 5 in which said image transfer belt is continuous.
- 7. An offset printing system as claimed in claim 5 in which said base ply comprises a reinforcement material.
- 8. An offset printing system as claimed in claim 7 in which said reinforcement material comprises a woven fabric ply.
- 9. An offset printing system as claimed in claim 8 in which said woven fabric ply is rigid in a direction across the width of said belt and flexible along the longitudinal axis of said belt.
- 10. An offset printing system as claimed in claim 5 in which said base ply includes an inner surface which is capable of providing precise registration.
- 11. An offset printing system as claimed in claim 10 in which said inner surface comprises a high friction material.
- 12. An offset printing system as in claim 8 further including on a second side of the traveling web:a) at least a second ink source; b) at least a second plate cylinder having a replaceable sleeve, said replaceable sleeve adapted to have mounted thereon a printing plate, said printing plate adapted to receive ink from said second ink source; c) at least a second blanket cylinder which acts as the impression cylinder for said first blanket cylinder; d) at least a second image transfer belt having a surface positioned to contact both said second printing plate in a third nip, formed between said second plate and said second blanket cylinder, and the second side of the traveling web in a fourth nip, formed between said second blanket cylinder and said first blanket cylinder; e) at least a second image transfer belt tensioning system to register said second image transfer belt to said second blanket cylinder position in the area of said third and fourth nips for desired image transfer, and f) at least one image belt cleaning station adapted to remove residual ink from said surface of said second image transfer belt.
- 13. An offset printing system having the capability to print variable-sized images comprising:a source of ink; at least one plate cylinder and a replaceable sleeve for said plate cylinder, said replaceable sleeve adapted to have mounted thereon a printing plate, said printing plate adapted to receive ink from said ink source; at least one blanket cylinder; at least one image transfer belt positioned to contact said printing plate in a nip formed between said plate and blanket cylinders; an image transfer belt tensioning system having a plurality of tensioning rolls to register said image transfer belt to said blanket cylinder position in the area of the desired image transfer, wherein at least one of said tensioning rolls is temperature controlled; and an image belt cleaning station adapted to remove residual ink from the surface of said image transfer belt.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a division of U.S. Ser. No. 09/159,662, filed Sep. 24, 1998, pending.
US Referenced Citations (19)
Foreign Referenced Citations (4)
Number |
Date |
Country |
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May 1924 |
DE |
3907366 |
Sep 1990 |
DE |
4442983 |
Jun 1996 |
DE |
0225509 |
Jun 1987 |
EP |