Patent ID: 7442485
Filing Date: 2008-10-28
Classification: B41C

Abstract:
1. A lithographic printing process which comprises the steps of: imagewise exposing to infrared light a presensitized lithographic plate which comprises a hydrophilic support and an image-forming layer containing an infrared absorbing agent, a radical polymerization initiator, an ethylenically unsaturated polymerizable compound and a binder polymer, said polymerization initiator being a salt of a sulfonium ion with an anion selected from the group consisting of (1) hydrogensulfate ion, (2) a sulfate ester ion, (3) a polymer having a carboxylate ion, (4) a polymer having a sulfonate ion, (5) a polymer having an anion of —S0 removing the image-forming layer within the unexposed area while mounting the lithographic plate on a cylinder of a printing press; and then printing an image with the lithographic plate while mounting the lithographic plate on the cylinder of the printing press.