LASER DIRECT PROCESSING LITHOGRAPHIC PRINTING PLATE MATERIAL AND PRINTING METHOD USING THE SAME

PROBLEM TO BE SOLVED: To obtain a printing plate without requiting a development treating process by irradiating pulse oscillation laser beams on a treated surface of a carrier having a metal surface to which treatment of hydrophilicity or ink repellency is applied, and giving ink adhesivenents to the irradiated surface. SOLUTION: In a manufacture of a laser direct processing lithographic printing material, a treated surface of a carrier having a metal surface to which the treatment of hydrophilicity or ink repellency is applied is irradiated with pulse oscillation laser beams. Thereby, ink adhesveness is given to the surface. The obtained plate material is irradiated wit laser beams according to an image, and lithographic printing ink is stuck onto an irradiated part of the plate material to carry out offset printing. In that case, as the pulse oscillation laser, an Nd:YAG laser, an excimer laser, etc., are used. For making hydrophylicity treatment, polyvinyl phosphonate, polyvinyl sulfonate, etc., are used. Further, the ink expellency treatment is carried out by coating silicone or fluoropolymer.