GB1062092A - Improvements in and relating to electrophotographic material - Google Patents

Abstract

1,062,092. Coated paper. AZOPLATE CORPORATION and RIEGEL PAPER CORPORATION. Feb. 14, 1964 [Feb. 15, 1963], No. 6320/64. Heading B2E. [Also in Divisions D1 and H1] A coated material consists of a duplex paper base bearing a conductive film resistant to penetration by water and organic solvents and, optionally, on top of this film a carbon-filled clay coating. The lower layer of the duplex paper may be impregnated with a conductive resin while the upper layer is filled with carbon black or powdered metals such as copper and aluminium. The conductive film consists of a filling of carbon-black, copper or aluminium in a binder such as plasticised nitrocellulose (e.g. using dibutyl phthalate), an oil-modified alkyd resin, an epoxy resin, or polyvinyl chloride. The carbon-filled clay coating may be based on a conventional starch-clay or casein-clay mixture optionally containing 10-20 wt. per cent. of a butadiene-styrene latex. In the example of Fig. 2 cylinder machines 17, 18 are respectively fed with a carbon-bearing pulp furnish of predominantly cellulosic fibres and with a carbon-free pulp furnish of cellulosic fibres are merged while wet and passed through drier 19. (A single cylinder machine and a fourdrinier machine may instead be used). The duplex web may be machine calendered and/or supercalendered. The conductive film is applied by gravure applicator 20 and smoothed by bar 21 before being passed through a curing oven 22. The process may be stopped here or, as shown, may be continued by the application by wire or blade coater 23 of a solvent carried mixture of zinc oxide and silicone resin. The material, after its passage through curing oven 24, forms an electrophotographic material having a photoconductive surface layer.