Waterless lithographic printing plate

摘要

A waterless presensitised plate is exposed imagewise using a computer controlled digitised laser beam. The plate has a hydrophilic or non-hydrophilic substrate carrying, in order: (i) a layer sensitive to actinic radiation; (ii) a solvent swellable, ink repellant silicone rubber layer; (iii) a polymeric protective layer, layers (ii) and (iii) being transparent to actinic radiation; and (iv) a gelatino Ag halide emulsion layer contg. polymeric binders or keying agents to promote adhesion to the protective layer. Layer (i) is: (a) an oleophilic photo-adhesive coating contg. an ethylenically unsatd. photopolymerisable monomer or oligomer which adhesively polymerises on exposure to active radiation; or (b) a photo-releasable adhesive coating contg. quinonediazide cpds. which becomes soluble on exposure to actinic radiation.