GB345263A - Improvements in or relating to printing processes - Google Patents

Abstract

345,263. Printing-surfaces. WADE, H., 111, Hatton Garden, London.-(American Multigraph Co. ; Kelly Avenue, Cleveland, Ohio, U.S.A.) Dec. 17, 1929, No. 38638. [Class 100 (ii).] A printing-plate, on which an image has been prepared, is treated with a substance which will render the plate initially ink-repellent on the plain portions but will not injure the image, and printing is effected with an ink which will adhere on to the image and contains a substance which will continue the surface-treatment of the plate and maintain the plain portions in ink-repellent condition. An aluminium plate for planographic printing has the image produced thereon in fatty or greasy ink by means of a lithographic pencil or other method, and the surface is then rubbed with a solution of a nitrate or sulphate, preferably ammonium nitrate or sulphate, or aluminium, nickel, iron, or copper nitrate. After drying, direct or offset printing is effected with ordinary lithographic ink to which a substance similar to that used for treating the plate, and preferably ammonium nitrate or aluminium nitrate or sulphate, has been added, damping being unnecessary. In the preparation of a photomechanical plate, the nitrate or sulphate solution is added to the light-sensitive layer, and the plate, after exposure, is developed with a developer which will not dissolve the nitrate or sulphate. For intaglio printing, the aluminium or aluminiumcovered plate is etched in the usual way, the etched parts are inked with a fatty ink containing the nitrate or sulphate solution, and the remaining parts are rendered ink-repellent. If a zinc plate is to be used, a phosphate, preferably ammonium monohydrogen phosphate, is added to the preparing solution to prevent oxidation or corrosion of the plate.