ORIGINAL PLATE OF PLANOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To provide a planographic printing plate having high age stability when a photopolymerizable original plate of a planographic printing plate obtained by disposing a photosensitive layer on the surface of a base is imagewise exposed and developed and printing is carried out even after the original plate is stored under conditions of high temperature and high humidity over a long period of time after production. SOLUTION: The original plate has a photopolymerizable photosensitive layer containing a compound having an addition polymerizable ethylenically unsaturated double bond, a titanocene photopolymerization initiator, an N- nitrosophenylhydroxylamine salt and an ester compound having >=200 deg.C boiling point and comprising a compound having a phenolic OH group and an inorganic acid on an aluminum base.