Patent ID: 6516722
Filing Date: 2003-02-11
Classification: B41C

Abstract:
A lithographic printing method on a lithographic printing machine comprising a plate cylinder for imaging, a blanket cylinder, an impression cylinder, and a film-coating unit, a film-hardening unit, an imaging unit and a cleaning unit, each unit of which is adjacent to the plate cylinder for imaging, which comprises the steps of at least (a) cleaning operation of cleaning said plate cylinder for imaging, (b) coating operation of coating a radiation-sensitive image-forming layer containing a polymer having a functional group which converts from hydrophilic to hydrophobic by heating on the surface of said plate cylinder for imaging, (c) hardening operation of hardening said image-forming layer to a solid state, and (d) surface conversion operation of forming an image pattern due to hydrophilic/hydrophobic conversion corresponding to the digital data to be printed on the surface of said image-forming layer wherein said functional group which is converted from hydrophilic to hydrophobic is selected from the group consisting of a carboxylic acid group and a carboxylate group, and wherein the conversion from hydrophilic to hydrophobic occurs by decarboxylation.