| 摘要 |
<p>1,032,264. Developing electrophotographic images. GEVAERT PHOTO-PRODUCTEN N.V. May 15,1964 [May 17, 1963], No. 20429/64. Heading G2H. Latent electrostatic images on photoconductive zinc oxide layers are developed by applying an aqueous solution of pH between 2 and 7 of a terricyanide and a lenco base of a dye to give coloured water-proof images. Specified lenco bases are those of triphenylmethane dyes,diphenylmethane dyes diphenylasenium salts, indigo dyes and methylene blue which are oxidised to dyes in the presence of zinc ions. The developer solution may contain a cationic dye. A solution containing ferricyanide may be applied first followed by a solution containing the lenco base and the dye or viceversa. The developer solution may also contain a water-soluable or water-dispersable resin. The developer is applied to the latent image by a helically grooved roller which dips into the developer bath, the material passing between a guiding roller and the grooved developer roller. Multicoloured images may be produced by exposing the photoconductive layer successively through a blue, green or a red filter uniformly charging and developing with a yellow, magenta or cyan dye as appropriate after each exposure.</p> |
