GB536395A - Electric sensitive paper - Google Patents

Abstract

536,395. Copying telegraphy. FINCH, W. G. H. April 8, 1940, No. 6325. Convention date, April 7, 1939. [Class 40 (iii)] [Also in Group VIII] Conductive paper for dry electric recording, e.g. in the reproduction of pictures, and containing coloured conducting material, e.g. lampblack, is coated with a binder, e.g. nitrocellulose, cellulose acetate, natural or synthetic resins or gums, casein, &c. pigment, e.g. titanium dioxide, zinc oxide, lead oxide, or lead carbonate, and a metal powder or conductive metal salt, e.g. aluminium powder, nickel chloride, &c. The coating mixture is thinned as with alcohol and applied by spraying, dipping, flowing, &c. or preferably using a roll having crossing series of grooves leaving small block segments of the surface each picking up a small globule of coating, the globules coalescing to give a uniformly thick deposition on to the paper. The coating may also include aniline hydrochloride or cadmium iodide, &c. to increase the sensitivity of the titanium dioxide, &c. to give clearer images, and potassium or sodium nitrates &c. to cause converted coating to be flaky. The paper on which the coating is applied is rendered conductive by addition to the pulp of as much lampblack, &c. as it will hold. Rag paper 0.003 inches thick with a coating 0.00025 inches thick may be used.