Patent ID: 7790355

Claim:
A method of lithographically printing images on a receiving medium, comprising in order: (a) providing a lithographic plate comprising (i) a hydrophilic substrate; (ii) an oleophilic photosensitive layer comprising a polymeric binder, a free radical polymerizable monomer, a free radical initiator, and a sensitizing dye; and (iii) a water soluble or dispersible overcoat; wherein said photosensitive layer is capable of hardening upon exposure to a laser having a wavelength selected from 200 to 1100 nm; (b) imagewise exposing said plate with said laser to cause hardening of the photosensitive layer in the exposed areas; (c) applying an aqueous solution containing a deactivating agent to said exposed plate to deactivate the photosensitive layer; and (d) contacting said deactivated plate with ink and fountain solution on a lithographic press 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 under the same room lighting for said steps (a) to (d), said photosensitive layer in the non-imagewise-exposed areas is incapable of hardening under said room lighting within an amount of time of 20 minutes and is capable of hardening under said room lighting for more than said amount of time, and the total exposure time to said room lighting before said plate being deactivated is shorter than said amount of time so that the non-imagewise-exposed areas of the plate are not hardened.