Variable cut-off offset press system and method of operation

An offset printing system for printing onto a substrate, said offset printing system comprising:

• a) a source of ink;
• b) a source of a coating material;
• c) at least one plate cylinder adapted to have thereon a replaceable sleeve providing a printing plate, said printing plate adapted to receive ink from said ink source to form an inked image;
• d) at least one impression cylinder;
• e) an image transfer belt positioned to receive a film of coating material from said source of coating material and to contact said printing plate in a nip formed between said plate and impression cylinders such that said inked image offsets onto said film, and wherein said film of said coating material is transferable with said inked image from said image transfer belt onto the substrate to provide protection or a desired finishing to said inked image;
• and
• f) an image transfer belt tensioning system configured to register said image transfer belt to said impression cylinder positioned in the area of desired image transfer.

An offset printing system for printing onto a substrate, said offset printing system comprising:

• a) at least two sources of ink having at least first and second different colors;
• b) at least two plate cylinders adapted to have thereon a respective replaceable sleeve providing a printing plate adapted to receive ink from one of said at least two sources of ink;
• c) at least two impression cylinders, each of said at least two impression cylinders having an outer diameter unequal to an outer diameter of said respective replaceable sleeve;
• d) an image transfer belt positioned to contact each of said printing plates at respective nips formed between respective ones of said plate cylinders and said impression cylinders and to receive in registration at least first and second inked images from said printing plates to form a multi-colored image on a first side of said image transfer belt;
• e) an image transfer belt tensioning system adapted to register said image transfer belt to respective ones of said impression cylinders positioned in the area of desired image transfer and having tension rollers, wherein at least one of said tension rollers is temperature controlled to minimize contraction and expansion of said image transfer belt;
• f) a coating station adapted to apply a film of a coating material to said first side of said image transfer belt, and wherein said film of said coating material is transferable with said multi-colored image from said image transfer belt onto the substrate to provide protection or a desired finishing to said multi-colored image;
• and
• g) an image belt cleaning station adapted to remove residual material from the surface of said mage transfer belt after image transfer of said multi-colored image and film from said image transfer belt to the substrate.