GB1161001A - Improvements in or relating to Photographic Copying Processes and Apparatus - Google Patents

Abstract

1,161,001. Photo-copying apparatus. W. ZINDLER [trading as LUMOPRINT ZINDLER K.G.]. Nov.16, 1966 [Nov.25, 1965], No.51424/66. Headings G2A and G2C. Apparatus for carrying out a silver salt diffusion transfer process using a negative material, on the silver halide emulsion layer of which an image is formed, and a receptor material to which the image is transferred, includes two baths for containing liquids, one 22 for moistening the exposed negative material for development and another 21 which contains a liquid having in aqueous solution, reduction nucleii and a silver salt solvent for moistening the receptor material, a pair of common squeeze rollers 9, 10 for comprising the materials in contact, and another pair of squeeze rollers 11, 12 for the moistened receptor material between its bath 21 and the first rollers. The liquid baths may be replaced by roller applicators. Shells 1 and 2 contain the liquids and have guide webs 3, 4, 5, 6 formed as raised ribs to reduce friction and inclined to the direction of advance. Excess liquid is removed from the receptor sheet at rollers 11, 12 and runs back into bath 21 while excess liquid from the rollers 9, 10 runs back to bath 22. The rollers are driven through transmissions 145, 146, 147 by motor 144. In another form, the rollers are driven by separate motors, the common squeeze rollers rotating more slowly than the preceding rollers so as to bow the sheet upwards, Fig.3a (not shown), and facilitate draining. Certain guides are omitted, the planes containing the rollers being inclined to direct the sheets to the common rollers. In yet another form, Fig.5 (not shown), an exposure light source (99) is mounted within translucent glass cylinder (98) mounted between rollers (94, 95, 96) carrying a guiding band (97). Processing solution is stored in two elastic containers (100, 101) and supplied through pipes (104, 105) to the baths as the containers are compressed by plate (102) in response to hand-crank operated lever (103). According to the silver salt diffusion transfer process of the present invention, the receptor material may be paper, film or textile material and is moistened with an aqueous solution containing reduction nuclei and a silver salt solvent. The solution may comprise 0À02% hexachloroplatinic (IV) acid and/or gold (III) chloride hydrochloride.