Patent ID: 6548222
Filing Date: 2003-04-15
Classification: B41C,G03F,Y10S

Abstract:
A negative lithographic printing plate comprising on a substrate a thermosensitive layer; said thermosensitive layer being soluble or dispersible in and on-press developable with ink and/or fountain solution, and capable of hardening through polymerization or crosslinking upon exposure to an infrared radiation; and at least the hardened areas of said thermosensitive layer exhibiting an affinity or aversion substantially opposite to the affinity or aversion of said substrate to at least one printing liquid selected from the group consisting of ink and an abhesive fluid for ink; wherein said substrate has a roughened surface comprising peaks and valleys, and said thermosensitive layer is substantially conformally coated on the roughened substrate surface so that the surface of said thermosensitive layer has peaks and valleys substantially corresponding to the major peaks and valleys of the substrate microscopic surface; and said substrate has an average surface roughness Ra of from 0.2 to 2.0 microns, said thermosensitive layer has an average coverage of from 0.1 to 2.0 g/m2, and the avenge height of the valleys on the thermosensitive layer surface is at least 0.1 microns below the average height of the peaks on the thermosensitive layer surface.