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AssigneeAgfa-Gevaert
InventorsJoseph Vander Aa, Joan Vermeersch, Dirk Kokkelenberg
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A method of making a lithographic printing plate is disclosed which comprises the steps of 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; exposing the coating to heat, thereby inducing coalescence of the thermoplastic polymer particles at exposed areas of the coating; developing the precursor by applying a gum solution to the coating, thereby removing non-exposed areas of the coating from the support. According to the above method, the plate precursor can be developed and gummed in a single step.
A method of making a lithographic printing plate comprising the steps of
A method according to any of the preceding claims wherein the coating further comprises a contrast dye or pigment which provides a visible image after development.
A method according to any of the preceding claims wherein the thermoplastic polymer is a copolymer of styrene and at least 5 mole % of a nitrogen-containing monomer.
A method according to any of the preceding claims wherein the gum solution is a baking gum solution and the method comprises an additional baking step by heating the developed plate precursor at a temperature of at least 60° C.
A method according to any of the preceding claims wherein the gum solution contains a hydrophilic film-forming polymer and/or a surfactant.
A method according to any of the preceding claims wherein the gum solution contains an organic acid or a salt thereof.
A method according to any of the preceding claims wherein the gum solution has a surface tension lower than 50 mN/m and a pH between 5 and 8.
Dependencies are inferred from the claim text.