The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1993
Filed:
Mar. 18, 1991
Edward P Patrick, Murrysville, PA (US);
A Victor Pajerski, New Kensington, PA (US);
Aluminum Company of America, Pittsburgh, PA (US);
Abstract
An essentially flat 'arc-grained' surface of a sheet of aluminum alloy is produced with a coarse and non-uniform microstructure which, after it is coated with a durable phosphate-free coating, provides excellent lithoplate. Though such arc-grained microstructure is much coarser than an electrochemically etched surface typically used on lithoplate, the very coarse surface is peculiarly well-adapted to provide durable lithoplate after it is coated with a phosphate-free protective surface. After the coated surface is coated with a photoresist the excellent resolution of prints is maintained over a large number of repeated uses in an off-set printing press. A method of producing lithoplate comprises, controlledly rastering an A-C, or D-C reverse polarity plasma-generating electric arc on an aluminum sheet less than 30 mils thick, kept distortion-free on a mounted surface such as on a cylindrical drum; then coating the arc-grained surface with a hard and durable, inert phosphate-free coating while maintaining a capillary microstructure in the surface adapted to provide a support for a photoresist for use in lithographic printing of adequate resolution.