POSITIVE TYPE PHOTOSENSITIVE COMPOSITION, POSITIVE TYPE PHOTOSENSITIVE PLANOGRAPHIC PRINTING PLATE AND POSITIVE IMAGE FORMING METHOD

摘要

PROBLEM TO BE SOLVED: To obtain a photosensitive planographic printing plate having good sensitivity, chemical resistance and printing resistance. SOLUTION: In a positive type photosensitive compsn. contg. an alkali-soluble resin (a) having phenolic hydroxyl groups and a photothermic conversion material (b) but not contg. a quinonediazido compd., an alkali soluble resin (a-1) having esterified phenolic hydroxyl groups as at least part of the phenolic hydroxyl groups is contained as the alkali-soluble resin (a).