Patent ID: 8652758

Claim:
A method of imaging a lithographic printing member, the method comprising the steps of: (a) providing a lithographic printing member comprising (i) an imaging layer that itself comprises a first polymer binder and, dispersed therein, particles coalesceable into a second polymer binder at a thermal coalescing temperature substantially above room temperature, (ii) a material that absorbs imaging radiation and is heatable thereby to a temperature of at least the thermal coalescing temperature, and (iii) a substrate disposed below the imaging layer, wherein: (1) the first polymer binder is insoluble in but swellable by an aqueous liquid and comprises at least one of butyl methacrylate or butyl acrylate; (2) the second polymer binder is insoluble in and not swellable by the aqueous liquid and comprises at least one of styrene and butyl acrylate; (3) the first and second polymer binders collectively exhibit a first lithographic affinity for ink or a liquid to which ink will not adhere and the substrate exhibits a second lithographic affinity opposite to the first lithographic affinity; and (4) the particles comprise at least one of butyl(meth)acrylate, methyl(meth)acrylate, ethyl(meth)acrylate, styrene, (meth)acrylonitrile, N-phenyl maleimide, vinyl carbazole, or vinyl chloride, (b) exposing the printing member to imaging radiation in an imagewise pattern so as to heat the polymer particles to the thermal coalescing temperature to form the second polymer binder; and (c) after the second polymer binder has cooled to a solid form, subjecting the printing member to an aqueous liquid to remove unimaged portions of the imaging layer, thereby creating an imagewise lithographic pattern on the printing member.