Patent ID: 7073440

Claim:
A method of imaging a lithographic printing member, the method comprising the steps of: (a) providing a printing member having a first layer, a second layer thereunder, and a substrate beneath the second layer, wherein (i) the first layer is permeable to a solvent, (ii) in response to heat, the second layer undergoes a transition from an insoluble state to a soluble state, and (iii) the first layer and at least one of the second layer and the substrate have opposite affinities for at least one of ink and a liquid to which ink will not adhere; (b) exposing the printing member to imaging radiation in an imagewise pattern so as to cause at least a portion of the second layer exposed to the imaging radiation to undergo the transition; (c) subjecting the printing member to a solvent, the solvent permeating the first layer and dissolving soluble portions of the second layer; and (d) removing the first layer where the printing member received radiation, thereby creating an imagewise lithographic pattern on the printing member.