Patent ID: 7220530

Claim:
A light sensitive planographic printing plate material comprising a hydrophilic support and provided thereon, a light sensitive layer containing (A) an infrared absorbing dye, (B) a radical generating agent, and (C) a radically polymerizable compound, the light sensitive layer being an outermost layer, wherein the radical generating agent is selected from the group consisting of a sulfonium salt, a iodonium salt and a diazonium salt, and the radically polymerizable compound is a radically polymerizable oxirane compound represented by the following formula (1), wherein R 1 represents a hydrogen atom or a methyl group; R 2 represents a hydrogen atom or an alkyl group having a carbon atom number of not more than 6; and X 1 represents a single bond, a straight chained or branched alkylene group having a carbon atom number of from 1 to 8, an alkylene group in which a carbonyl group, an oxygen atom or a sulfur atom is intervened in the alkylene skeleton, an arylene group or an aralkylene group.