On-press development of thermosensitive lithographic plates
OwnerGary Ganghui Tenginventor
Life of this patent
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Abstract
This patent describes on-press ink and/or fountain solution development of lithographic plates having on a substrate a thermosensitive layer capable of hardening or solubilization upon exposure to an infrared laser radiation. The plate can be imagewise exposed with an infrared laser and then on-press developed with ink and/or fountain solution by rotating the plate cylinder and engaging ink and/or fountain solution roller. The developed plate can then directly print images to the receiving sheets. The imagewise exposure can be performed off the press or with the plate being mounted on the plate cylinder of a lithographic press.
Claims41
A method of lithographically printing images on a receiving medium, comprising in order:
- (a) providing a lithographic plate comprising (i) a substrate;
- and (ii) a thermosensitive layer comprising a polymerizable monomer or oligomer, an initiator capable of initiating the polymerization of said monomer or oligomer, and an infrared absorbing dye or pigment;
- wherein said thermosensitive layer is capable of hardening upon exposure to an infrared laser radiation, is soluble or dispersible in and on-press developable with ink and/or fountain solution, and exhibits an affinity or aversion substantially opposite to the affinity or aversion of said substrate to at least one printing liquid selected from the group consisting of ink and an abhesive fluid for ink;
- (b) imagewise exposing the plate with the infrared laser radiation to cause hardening of the thermosensitive layer in the exposed areas;
- and
- (c) contacting said exposed plate with ink and/or fountain solution on a lithographic press to remove the thermosensitive layer in the non-hardened areas, and to lithographically print images from said plate to the receiving medium.
A method of lithographically printing images on a receiving medium, comprising in order:
- (a) mounting onto a plate cylinder of a lithographic press a lithographic plate comprising (i) a substrate;
- and (ii) a thermosensitive layer capable of hardening through polymerization or solubilization through decomposition upon exposure to an infrared laser radiation, the non-hardened or solubilized areas of said thermosensitive layer being soluble or dispersible in and on-press developable with ink and/or fountain solution, and said thermosensitive layer exhibiting an affinity or aversion substantially opposite to the affinity or aversion of said substrate to at least one printing liquid selected from the group consisting of ink and an abhesive fluid for ink;
- (b) imagewise exposing the plate with the infrared laser radiation to cause hardening or solubilization of the thermosensitive layer in the exposed areas;
- and
- (c) operating said press to contact said exposed plate with ink and/or fountain solution to remove the thermosensitive layer in the non-hardened or solubilized areas, and to lithographically print images from said plate to the receiving medium.
The method of clam 35 wherein said plate filer includes a fountain solution soluble or dispersible overcoat on the thermosensitive layer, said overcoat comprising a water-soluble polymer.
Dependencies are inferred from the claim text.