Method of making a heat-sensitive lithographic printing plate

Abstract

A method of making a lithographic printing plate is disclosed which comprises the steps of (1) providing a lithographic printing plate precursor comprising (i) a support having a hydrophilic surface or which is provided with a hydrophilic layer and (ii) a coating provided thereon which comprises hydrophobic thermoplastic polymer particles; (2) exposing the precursor to IR-light or heat, thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; (3) applying a hydrophilic protective layer on the coating; and then, (4) while the precursor is mounted on a print cylinder of a printing press, developing the precursor by supplying an aqueous dampening liquid and/or ink to said precursor while rotating said print cylinder whereby the coating and the hydrophilic protective layer are removed from the support on the non-exposed areas. According to the above method, the hydrophilic protective layer can be applied by coating a solution by means a spray nozzle or a jet nozzle and wherein the applied hydrophilic protective layer improves clean-out in an on-press development.

Dependencies are inferred from the claim text.