PLATE-MAKING METHOD FOR PLANOGRAPHIC PRINTING PLATE

摘要

PROBLEM TO BE SOLVED: To form an image having high resolution and form the image particularly in a light room by providing a silver thin film on a hydrophilic layer arranged on a support and heating the silver thin film by laser exposure so as to expose the hydrophilic layer. SOLUTION: A hydrophilic layer 2 is provided on a support 1 and a silver thin film 3 is layered on the layer 2 so as to make a planographic printing original plate (a). When the planographic printing original plate (a) is irradiated with laser beams so as to form a desired image pattern, the silver thin film 3 at a part irradiated with laser beam fuses with heat and the hydrophilic layer 2 is exposed so as to make a planographic printing plate. When the planographic printing plate is mounted in a planographic printing machine, ink is received at a remaining part of the silver thin film 3 and at the exposed hydrophilic layer 2, so that planographic printing becomes possible. The silver thin film 3 can be formed by a metal thin film forming method such as vacuum deposition and sputtering. The hydrophilic layer 2 can be obtained by coating a hydrophilic polymer having a coat-forming performance as a main material.