Patent ID: 8940474
Filing Date: 2015-01-27
Classification: B41C,G03F

Abstract:
1. A method for providing a lithographic printing plate comprising: A) imagewise exposing a positive-working lithographic printing plate precursor having an imageable layer to provide exposed and non-exposed regions using infrared radiation,  wherein the imageable layer comprises an infrared radiation absorbing compound and a primary polymeric binder in an amount of at least 40 weight % and up to and including 95 weight %, based on the total dry weight of the imageable layer, the primary polymeric binder comprising recurring units represented by either or both of the following Structures (Ia) and (Ib), in random order: wherein:  when both Structure (Ia) and (Ib) recurring units are present, the Structure (Ia) recurring units are present in an amount of at least 10 and up to and including 35 mol %, and the Structure (Ib) recurring units are present in an amount of at least 25 and up to and including 60 mol %, all based on total recurring units in the polymeric binder, R is a substituted or unsubstituted hydroxyaryl group, and  R B) processing the exposed lithographic printing plate precursor with a developer composition to remove the exposed regions in the imageable layer, wherein the developer composition is a silicate-free and sugar-free alkaline aqueous developer composition having a pH of at least 12 and comprising:  (a) a hydroxide,  (b) a metal cation M  (c) a chelating agent for the metal cation M  (d) an alkali metal salt different than all of a, b, and c above.