GB912833A - Sensitizable coated paper sheet adapted for electrophotographic reproduction - Google Patents

Abstract

912,833. Electrophotolithographic printing plates. PLASTIC COATING CORPORATION. March 25, 1959 [April 10, 1958], No. 10271/59. Drawings to Specification. Class 98 (2). [Also in Group XXXVI] A lithographic printing plate is made from an electrophotographic plate of a form suitable for attachment to the printing cylinder of a lithographic press by charging and exposing the plate in the usual way, developing the latent image using an hydrophobic oleophylic toner such as resin or wax, and rendering the untoned areas hydrophylic by treatment in acidified ferrocyanide solution. The electrophotographic plate comprises a sheet of paper carrying on one of its surfaces a flexible layer of metal which is in turn coated with a finely divided photoconductive zinc oxide dispersed in an electrically insulating . material. The paper sheet may be precoated with a casein-butadiene-styrene copolymer clay mixture, or a casein clay mixture, or with a lacquer. The metal layer is applied by cathode sputtering or vacuum metallising and consists of any metal applicable in this way e.g. aluminium, zinc, gold, silver, platinum, tungsten, cadmium, nickel, chromium, tantalum or molybdenum. The photoconductive zinc oxide is applied as a suspension in a solution of film forming material in an organic solvent. Suitable film forming materials are silicone, polyvinyl chloride, phenolic, polyester and methacrylate resins, polystyrene, polyethylenes, styrenated alkyl resins, vinyl acetate-vinyl chloride copolymer resins, styrene butadiene copolymers, polymerised iso-butyl methacrylate, and copolymers of n-butyl methacrylate and iso-butyl methacrylate, 1 part by weight of any of which may be mixed with 2.6-4.5 parts of zinc oxide to form a preferred photoconductive layer. Specification 912,836 is referred to.