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US 6,802,258 B2Granted
Method of lithographic printing with a reusable substrate
AssigneeAgfa-Gevaert
InventorsEric Verschueren, Joan Vermeersch
Life of this patent
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Abstract
A method for removing ink-accepting areas of a lithographic printing master is disclosed which enables to recycle the lithographic substrate of the printing master. The method comprises after a cleaning step a treatment of the recycled substrate with an aqueous solution having a pH<7.
Claims27
Direct-to-plate method of lithographic printing with a reusable substrate having a hydrophilic surface comprising the steps of:
- (a) making a negative-working imaging layer by coating on the hydrophilic surface a solution comprising hydrophobic thermoplastic particles;
- (b) making a printing master having ink-accepting areas by image-wise exposing the imaging layer to heat or light;
- (c) applying ink and fountain solution to the printing master;
- (d) removing the ink-accepting areas from the printing master by supplying a cleaning liquid to the imaging layer thereby obtaining a recycled substrate, wherein the cleaning liquid comprises an aqueous emulsion of an alcohol and a cyclic compound having at least one double bond, and
- (e) treating the recycled substrate by supplying a refreshing liquid consisting of an aqueous solution having a pH<7.
2 more elements
Dependencies are inferred from the claim text.