Patent ID: 6694880
Filing Date: 2004-02-24
Classification: B41C,B41N

Abstract:
An offset printing apparatus, comprising:a printing plate, having a surface being hydrophilic due to heat energy generated at a first temperature and being hydrophobic due to heat energy generated at a second temperature which is lower than the first temperature; a mounting section, on which the printing plate is mounted; preparation means, for forcibly making a whole of the surface of the printing plate either hydrophilic or hydrophobic in nature; recording means, for forming a region on a part of the surface of the printing plate so as to have the other nature than the nature formed by the preparation means; ink supply means, for supplying ink onto a hydrophobic region of the printing plate; and print means, for transferring the ink onto a print medium, wherein the preparation means heats the printing plate at the second temperature to make the whole surface of the printing plate hydrophobic, the recording means heats a part of the surface at the first temperature to form a hydrophilic region, and the heating means includes means for supplying vapor of an organic compound onto the surface of the printing plate.