GB1049872A - Method of producing xerographic plates - Google Patents

Abstract

1,049,872. Electrophotographic materials. RANK-XEROX Ltd. April 2, 1966 [April 2, 1962], No. 25919/66. Divided out of 1,049,871. Heading H1K. A method of producing a xerographic plate comprises forming upon a conductive support a layer comprising a mixture of finely divided inorganic photo-conductive particles and finely divided glass particles and heating the layer to the fusing temperature of the glass particles to fuse the layer to the support. The photo-conductive particles form up to 60 weight per cent of the fused layer. Oxide glasses are suitable but low-melting glass-forming sulphides such as arsenic sulphide and antimony sulphide are possible variants. Suitable support materials include aluminium, brass, stainless steel, copper, nickel, or zinc; and glass coated with tin oxide, with indium oxide, or with aluminium. Suitable photo-conductors are calcium-strontium sulphide, zinc sulphide, zinc oxide, zinc selenide, zinc titanate, zinc silicate, zinc-magnesium oxide, cadmium sulphide, cadmium selenide, mercuric sulphide, mercuric oxide, antimony sulphide, arsenic sulphide, arsenic selenide, gallium selenide, indium sulphide, titanium dioxide, and the lead oxides PbO and Pb 3 O 4 . Preferred materials are " phosphors " and materials containing zinc and/or cadmium and sulphur and/or selenium. Component materials for oxidic binders are discussed. The light sensitivity and dark decay characteristics of freshly prepared plates generally improve markedly during the first 24 hours after manufacture. Some plates with good electrical properties yield no picture or only pictures of poor quality but may be improved by polishing their surfaces (for example with rouge) or by soaking them in tap water for “ hour then drying them thoroughly with I.R. radiation. Distilled water and Lewis bases produce less improvement than tap water-acids are ruinous. The plates may be formed with a glossy overcoat constituted by a layer of clear glass binder or of such a material containing a quantity of photoconductor smaller than that in the main layer. A glossy surface may instead be obtained by contacting the free surface of the photo-conductive layer while it is still in a plastic or molten condition with a very smooth non-adherent surface which is removed subsequently. The xerographic properties become impaired when the surfaces of the plates are dulled by frequent use and may be restored by refiring the plates under the same conditions as when they were first made. Reference has been directed by the Comptroller to Specification 872,100.