GB401063A - Improved process for the production of mercurised printing plates - Google Patents

Abstract

401,063. Printing-surfaces. ZIMMERMANN, H. G., 41, Mavho Street, Bentleigh, Victoria, Australia. July 26, 1932, No. 21073. Convention date, July 27, 1931. [Class 100 (ii).] A printing-plate having mercurial non- printing areas is prepared by coating a metal amalgamable with mercury with a non-amalgamable metal, applying the design in a resist to the coating, etching the unprotected parts to expose the lower metal, amalgamating the exposed parts with mercury, treating the amalgamated surfaces with a suitable fluid, e.g. a solution of silver nitrate and nitric acid, to produce a layer of mercury silver amalgam having a matt surface, and again amalgamating the treated surfaces with metallic mercury. A base of copper or brass, or of other metal coated with copper or brass, is provided with a coating of nickel on which the design is produced in a resist of e.g. bichromated fish glue, and the nickel, and, if desired, some of the underlying copper is etched away by perchloride of iron. The plate is then treated with a solution of mercurous nitrate and then with metallic mercury. The plate is afterwards treated with a solution of nitrate of silver and nitric acid until a matt surface is obtained, after which it is rubbed with metallic mercury. The Specification as open to inspection under Sect. 91 states also that the non-printing areas may be replenished with mercury during the printing operation by adding mercury to the ink or by spraying mercury on to the inking rollers. This subject-matter does not appear in the Specification as accepted.