Patent ID: 7294447
Filing Date: 2007-11-13
Classification: B41C,B41N

Abstract:
1. A heat-sensitive lithographic printing plate precursor comprising (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer; and (ii) a coating provided thereon, the coating comprising an oleophilic layer which, upon image-wise exposure to heat or infrared light and subsequent immersion in an aqueous alkaline developer, dissolves in the developer at a higher dissolution rate in exposed areas than in unexposed areas, wherein the oleophilic layer comprises a polymer that is soluble in the developer and an organic dye in a amount sufficient to provide a visible color to the coating and wherein said organic dye does not reduce the dissolution rate of the unexposed areas in the developer, wherein the organic dye has a chemical structure according to the following formula: wherein D is a chromophoric group, L is a divalent linking group, x is 0 or 1, y and n are at least 1, and G is an anionic group or a group which can be rendered anionic by immersion of the coating in the developer, wherein the organic dye is one of the following formulas: wherein i and j are independently 0 to 3; k, l and o are independently 0 to 4; m and n are independently 0 to 5; p is 0 to 3; R R3, R4 and R with R R wherein G is independently selected from the group consisting of —COOH, —OH, —PO