Patent ID: 6444393
Filing Date: 2002-09-03
Classification: B41C,B41M,C09B

Abstract:
A photosensitive composition for a planographic printing plate that comprises the following components (a) and (b) and becomes soluble in an aqueous alkaline solution by heat generated by irradiation with an infrared laser:(a) the anionic, infrared-ray absorbing agent; and (b) a polymeric compound insoluble in water but soluble in an aqueous alkaline solution, wherein the anionic, infrared-ray absorbing agent includes a chemical structure that substantially absorbs infrared-ray radiation and generates heat, the chemical structure having a negative electric charge and the anionic infrared-ray absorbing agent is a compound represented by the following general formula (I): {Gaâˆ’â€”Mâ€”Gb}m Xm+â€ƒâ€ƒ(I) wherein, Ga âˆ’ represents an anionic substituent group which includes an oxygen atom, a sulfur atom or a carbon atom; M represents a conjugated chain of carbon atoms; Gb represents a neutral substituent group; and Xm+ represents a cation including a proton, said cation having a valence of from 1 to m, wherein m represents an integer ranging from 1 to 6.