Patent ID: 8100055
Filing Date: 2012-01-24
Classification: G03F

Abstract:
1. A method of lithographically printing images on a receiving medium, comprising in order: (a) providing within a light-tight cassette a lithographic plate comprising on a hydrophilic substrate an oleophilic photosensitive layer comprising a polymeric binder, a free radical polymerizable monomer, a free radical initiator, and a sensitizing dye; said photosensitive layer being soluble or dispersible in ink and/or fountain solution and capable of hardening upon exposure to an infrared laser having a wavelength selected from 750 to 1200 nm; (b) feeding said plate from said cassette to an exposure device to imagewise expose the plate with said laser to cause hardening of the photosensitive layer in the exposed areas; (c) automatically transferring said exposed plate to a deactivating device to contact said exposed plate with an aqueous solution containing a deactivating agent to deactivate the photosensitive layer; and (d) mounting said deactivated plate on a lithographic press to contact said plate with ink and/or fountain solution to remove the photosensitive layer in the non-hardened areas and to lithographically print images from said plate to the receiving medium; (e) wherein said plate is shielded with light-tight covers all the time in said steps (a) to (c) until it has been deactivated, and is open to white room light in said step (d).