Letterpress printing plate having printing surfaces with a low surface tension, and method of making
AssigneeBonner Zeitungsdruckerei und Verlangsanstalt H. Neusser GmbH & Co. KG
InventorDieter Guls
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Abstract
A letterpress printing method is disclosed wherein a printing plate, having plastic surface with a critical surface tension in the range of approximately 18-35 mN/m, is engraved or otherwise provided with raised ink-bearing impression sites and the printing plate is used for printing in a letterpress printing machine. As examples, the plastic surface of the printing plate may comprise a fluoropolymer, polytetrafluoroethylene or a copolymer of tetrafluoroethylene and hexafluoropropylene. The low surface tension is shown to enhance the printing quality in this environment.
Claims10
A letterpress printing method comprising the steps of:
- (a) providing a printing plate having a plastic surface with a critical surface tension substantially in the range of 18-35 mN/m, said plastic surface comprising a fluoropolymer;
- (b) creating a relief in said surface of said printing plate to form raised ink-bearing impression sites by a photochemical process which includes a photochemical reaction;
- and
- (c) printing with said printing plate using a letterpress type printing machine.
A printing plate for use with a letterpress type printing process having ink-bearing impression sites oil with plastic surfaces, the improvement comprising:
- (a) the plastic surfaces of the ink-bearing impression sites having a critical surface tension substantially in the range of 18-35 mN/m;
- (b) the impression sites being formed from a photochemical relief layer;
- and
- (c) the impression sites in tile relief layer further containing a fluoropolymer and a chemical group to adjust the critical surface tension of tile polymer.
Dependencies are inferred from the claim text.