Patent ID: 8129090
Filing Date: 2012-03-06
Classification: B41C,G03F

Abstract:
1. A method of lithographically printing images on a receiving medium, comprising in order: (a) providing a positive-working lithographic printing plate comprising on a hydrophilic substrate an oleophilic photosensitive layer, wherein said photosensitive layer is capable of solubilization either upon exposure to a laser having a wavelength selected from 200 to 1200nm or upon exposure to said laser followed by heating, said photosensitive layer in the solubilized areas is soluble or dispersible in ink and/or fountain solution; (b) imagewise exposing said plate with said laser to cause solubilization of the photosensitive layer in the exposed areas, or to activate the photosensitive layer in the exposed areas so that it can be solubilized upon heating; (c) overall heating said plate to 60 to 160° C. for 1 to 240 seconds to cause solubilization or further solubilization of the photosensitive layer in the exposed areas without causing solubilization of the non-exposed areas; (d) developing said plate with ink and/or fountain solution on a lithographic press to remove the exposed areas of said photosensitive layer; and (e) lithographically printing images from said plate to the receiving medium.