GB1447104A - Electrophoretic imaging process - Google Patents

Abstract

1447104 Electro-phoretic imaging process XEROX CORP 19 Dec 1973 [4 Jan 1973] 58827/73 Heading G2H The process comprises (a) providing between first and second electrodes, a layer of an imaging suspension comprising imaging particles in electrically insulating material that is liquid during at least the time of migration of said imaging particles in said process, said particles comprising chromogenically reactive material; (b) providing between said electrodes, an imaging receiving layer comprising a co-reactant for said chromogenically reactive material; (c) utilizing said electrodes to apply an electrical field across said imaging suspension; (d) during (c), exposing said imaging suspension to an imagewise pattern of activating electromagnetic radiation to form an image on said image-receiving layer by migration of said imaging particles; and (e) chromogenically reacting said chromogenically reactive material in said image with said co-reactant. Preferably one of the electrodes is transparent and imaging exposure is effected through it. The imaging particles may be electrically photo-sensitive, or accompanied in the suspension by other particles which are electrically photo-sensitive, or be used in conjuction with an electrode provided with a photo-conductive layer. Many suitable pairs of chromogenic co-reactants are listed and include many examples of: polymer coated surfaces, and photo-conductive zinc oxide particles that will on heating catalyze the carbonation of the polymer; compounds that release sulphur, and metal salts or soaps; organic acids, alkaline compounds or compounds that release alkali on heating, and pH sensitive compounds; oxidizing agents, and compounds that change colour on oxidation; 1-phenyl-3-pyrazolidinone or derivatives thereof, and silver or gold salts, triazolium compounds, or leocophthalocyanines; 8-hydroxy-1,2,3,4-tetrahydroquinoline or derivatives thereof, and salts or soaps of metals, or oxidizing agents; phenols or naphthols, and metal salts or soaps, oxidizing agents, or nitroso compounds; compounds containing an active methylene group, and 5-bromo-2-amino-thiazoles; amines, and aromatic aldehydes or ketones; nitroso derivatives, and aromatic hydroxy compounds, metal salts, or amines; triazene compounds and diazotype coupling agents; aromatic amines or amino-hydroxy compounds, and sulphur containing compounds, silver, gold, mercury or cadmium salts, oxidizing agents, nitroso compounds, or aromatic diazonium compounds; nitro compounds, and metal salts or oxidizable compounds such as 4-amino-diphenylamine-2-sulphonic acid; and diazonium salts, and couplers therefor. The chromogenic reaction may be effected by treatment of the co-reactants with ammonia, a solvent or heat, according to their nature, and the image may be fixed by heat.