ORIGINAL PRINTING PLATE FOR LITHOGRAPHIC PRINTING PLATE AND METHOD FOR LITHOGRAPHIC PRINTING USING IT

PROBLEM TO BE SOLVED: To provide an original printing plate for a lithographic printing plate with excellent on-machine developing properties, fine line reproducibility, inking properties at print starting, LGT safety, etc., and a method for lithographic printing using it. SOLUTION: The original printing plate for the lithographic printing plate has (A) an image recording layer comprising an infrared absorbing agent, a polymerization initiator and a polymerizable compound, and removable with a printing ink, a dampening water or both of them, and (B) an overcoat layer comprising a coloring material particle, on a substrate in this order. The method for lithographic printing comprises mounting the original printing plate for the lithographic printing plate on a printing machine and exposing it with an infrared laser into an image-like pattern, or exposing it with the infrared laser into the image-like pattern and mounting it on the printing machine, feeding a printing ink and the dampening water to the original printing plate, removing an unexposed part with the infrared laser on the image recording layer, and performing printing. COPYRIGHT: (C)2005,JPO&NCIPI