Presensitized plate for use in making lithographic printing plate.

摘要

A presensitized plate comprises a substrate having a hydrophilic surface provided thereon with a light-sensitive layer containing an alkaline water-soluble or swellable photocrosslinkable polymer carrying photodimerizable unsaturated double bonds and an optional intermediate layer between the substrate and the light-sensitive layer wherein the light-sensitive layer and/or the intermediate layer contain a co-polycondensed diazo resin having, as the structural units, those derived from an aromatic compound having at least one carboxyl group and an aromatic diazonium compound, for instance 4 - diazodiphenylamine salt. The light-sensitive layer and/or the intermediate layer of the plate exhibit high adhesion to the substrate or the like while maintaining high sensitivity and excellent quality thereof and the plate can be developed with an alkaline water to provide lithographic printing plates having excellent quality such as printing durability.