ORIGINAL PLATE OF PLANOGRAPHIC PRINTING PLATE WITHOUT REQUIRING DAMPENING WATER

摘要

PROBLEM TO BE SOLVED: To provide an original plate of a planographic printing plate without requiring dampening water having such good storage stability as to prevent degeneration and the lowering of sensitivity even after long-term storage and to provide an original plate of a planographic printing plate not requiring dampening water having a high safety recording layer having high sensitivity to laser light for writing and not generating a harmful material in recording. SOLUTION: Each of the original plates is obtained by stacking a photothermal converting layer which converts laser light to heat and a silicone rubber layer in this order on a base and the photothermal converting layer contains a photothermal converting agent and a polyurethane resin having at least one carboxyl group and a polymerizable or crosslinkable functional group.