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US 7,608,388 B2Granted
Inkjet-imageable lithographic printing members and methods of preparing and imaging them
AssigneePresstek, Inc.
InventorsAlbert S. Deutsch, Eugene L. Langlais
Life of this patent
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Abstract
Lithographic printing plates are imaged using an inkjet printer to imagewise apply a chemical or masking agent onto the plate surface. In some embodiments, the chemical inhibits a photoreaction in the top layer.
Claims30
A system for lithographic printing comprising:
- (a) a printing member comprising a soluble hydrophilic first layer that itself comprises a photoreactive reagent, and a second oleophilic layer thereunder, and
- (b) an imaging fluid comprising a photoreaction-inhibiting agent comprising a nitroso dimer inhibiting system.
A method of imaging a lithographic printing member, the method comprising the steps of:
- (a) providing a printing member comprising a soluble top layer having a first lithographic affinity and comprising a photoreactive reagent and a layer thereunder having a second lithographic affinity opposite to the first lithographic affinity, wherein in response to an imaging fluid, the reactivity of the photoreactive reagent is reduced;
- (b) dispensing the imaging fluid in an imagewise pattern, the imaging fluid chemically reacting with the top layer and inhibiting the reactivity of the photoreactive reagent therein;
- (c) thereafter exposing the printing member to an energy source to initiate a photoreaction in areas where the imaging fluid has not been dispensed, the photoreaction transforming said areas from a water-soluble state to a water-insoluble state;
- (d) removing unreacted portions of the top layer, thereby creating an imagewise lithographic pattern on the printing member.
1 more element
Dependencies are inferred from the claim text.