A method for the production of planographic printing forms, which is not in accordance with the print pattern amalgamierbare, the printing ink which assumes a helicoidal guide parts and the printing ink repelling contain

摘要

265,294. Trist, A. R. Nov. 5, 1925. Printing-surfaces. - A planographic printing- plate having ink-retaining areas and mercurial ink-repelling areas comprises an electrodeposited lay a of copper or other metal with which mercury can amalgamate, and an electrodeposited layer b of nickel or other metal, unaffected by mercury, to which printing ink will adhere, and provided with recesses exposing the layer a and filled with a number of films e - - i of two metals electrodeposited alternately, one of these materials, e.g. copper, forming a hard amalgam with mercury and the other e.g. silver or gold taking a high polish when treated with mercury, a film of this metal being outermost, and the surface of the plane being treated with mercury to produce the ink-repelling areas. In the production of such a plate, a base 3 of iron is provided electrolytically with a layer a of copper of about one or one and a half thousandths of an inch in thickness and a layer b of nickel of about the same thickness is deposited upon the copper. The ink-retaining areas of the plate are protected with an acid resist c and the plate etched to form recesses extending completely through the plate b and into the plate a to a depth of about one ten-thousandth part of an inch. A film e of copper, gold, or silver is deposited electrolytically on the bottoms of the recesses and further films alternatively of copper and gold or silver are deposited to fill the recesses. The ridges k formed at the edges of the films are removed by abrasion and the plate treated with mercury. The resist c may be removed or allowed to remain. Specification 225,928 is referred to.