# US 4,395,472 A · Plain paper reproduction process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,395,472 A - Document ID: US4395472A - Status: Granted - Kind: A - Application number: 06/275,207 - Filed: 1981-06-19 - Granted: 1983-07-26 - Earliest claimed: 1981-06-19 - Inventors: Jean J. Robillard - Web page: https://patentgrep.com/patent/US4395472A ## CPC - B41M 5/3825: {Electric current carrying heat transfer sheets} - G03G 5/02: Charge-receiving layers (G03G5/153 takes precedence) - G03G 5/12: Recording members for multicolour processes - G03G 17/00: Electrographic processes using patterns other than charge patterns, e.g. an electric conductivity pattern; Processes involving a migration, e.g. photoelectrophoresis, photoelectrosolography; Processes involving a selective transfer, e.g. electrophoto-adhesive processes; Apparatus essentially involving a single such process - B41M: PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING, (correction of typographical errors B41J; processes for applying transfer pictures or the like B44C1/16; fluid media for correction of typographical errors by coating C09D10/00; printing textiles D06P) - G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY ## Abstract Monochromatic or polychromatic photographic images are directly developed on plain paper by a photodielectric selective sublimable dye transfer process. A photosensitive belt containing a photodielectric material and a binder is exposed to a light image and the exposed parts are then passed in contact with a plain paper together with a carrier of sublimable dye under pressure and the application of an electromagnetic field. Multicolor images are formed by exposing the original through three separation filters; for example, red, blue and green on three successive areas of the photosensitive belt and each exposed area passed in contact with a plain paper and three successive carriers of sublimable dyes of color corresponding to the separation filters. ## Claims ### Claim 1 A light sensitive photographic process for producing a permanent record on plain paper of a light image which comprises: (a) exposing to said image the surface of a photodielectric recording medium supported on a plastic belt, said photodielectric medium comprising a layer of a homogeneous intimate mixture of photodielectric pigments dispersed in a binder which exhibits a change of dielectric constant and dielectric loss factor in those areas of said photodielectric recording medium exposed to said light image and forming as a result of exposure to said image a latent image in terms of local variations of dielectric constant and dielectric loss factor in said photodielectric recording medium; (b) contacting the surface of said exposed photodielectric recording medium with the surface of a plain paper image receiving sheet backed with a plastic substrate coated with an image forming medium comprising a dispersion of sublimable dyes in a binder, the surface of said image forming medium being in contact with said plain paper image receiving sheet; (c) impressing a high frequency electric field through said photodielectric recording medium, plain paper image receiving sheet and image forming medium to provide the sublimation of the sublimable dyes of said image forming medium in selected areas corresponding to said light image onto said plain paper receiving sheet by selective generation of heat due to dielectric losses in said photodielectric recording medium, said heat generation in said photodielectric recording medium being substantially proportional to the change in dielectric constant and dielectric loss factor in said photodielectric recording medium according to the previous exposure of said medium to said radiation image, thereby producing a photographic record of the image made of sublimed dyes from said image forming medium onto said plain paper image receiving sheet. ### Claim 2 (depends on 1) A process according to claim 1 wherein the photodielectric pigment is selected from the group consisting of: zinc oxide, tin oxide, lead oxide, zirconium oxide, bismuth oxide, antimony oxide, aluminum oxide, cerium oxide, zinc sulfide, cadmium sulfide, copper sulfide, lead sulfide, antimony sulfide and cadmium telluride. ### Claim 3 (depends on 1) A process according to claim 1 wherein the sublimable dyes in said image forming medium are selected from the group consisting of: Anthraquinone dyes, Azo dyes and Nitroarylamine dyes. ### Claim 4 (depends on 1) A process according to claim 1 wherein the binder in said photodielectric medium is selected from the group consisting of: butadiene, styrene, butadiene copolymers, nylon and silicone resins. ### Claim 5 (depends on 1) A process according to claim 1 wherein the plastic belt is made of a material selected from the group consisting of: teflon, polyethylene and polystyrene. ### Claim 6 (depends on 1) A process according to claim 1 wherein said plastic substrate of said image forming medium is made of a material selected from the group consisting of: teflon, polyethylene, polystyrene, polyester, nylon and silicone impregnated paper. ### Claim 7 (depends on 1) A process according to claim 1 wherein the photodielectric pigment of said photodielectric medium is sensitized in the blue region of the spectrum, and the sublimable dye in said image forming medium is a blue dye. ### Claim 8 (depends on 1) A process according to claim 1 wherein the photodielectric pigment of said photodielectric medium is sensitized in the green region of the spectrum, and the sublimable dye in said image forming medium is a green dye. ### Claim 9 (depends on 1) A process according to claim 1 wherein the photodielectric pigment of said photodielectric medium is sensitized in the red region of the spectrum, and the sublimable dye in said image forming medium is a red dye. ### Claim 10 (depends on 1) A process according to claim 1 for multicolor copying of a multicolor light image which comprises providing a first photodielectric medium wherein the photodielectric pigment is sensitized in the blue region of the spectrum and a first image forming medium wherein said sublimable dye is a blue dye; providing a second photodielectric medium wherein the photodielectric pigment is sensitized in the green region of the spectrum and a second image forming medium in which the sublimable dye is a green dye; and providing a third photodielectric medium wherein the photodielectric pigment is sensitized in the red region of the spectrum, and a third image forming medium in which the sublimable dye is a red dye; exposing the surface of the first photodielectric recording medium to the multicolor light image through a blue filter, contacting the surface of the exposed first photodielectric recording medium with the surface of said plain paper image receiving sheet backed with a plastic substrate coated with said first image forming medium; exposing the surface of the second photodielectric recording medium to the multicolor light image through a green filter, contacting the surface of the exposed photodielectric recording medium with the surface of said plain paper image receiving sheet backed with a plastic substrate coated with said second image forming medium; exposing the surface of the third photodielectric recording medium to the multicolor image through a red filter, contacting the surface of the exposed photodielectric recording medium with the surface of said plain paper image receiving sheet backed with a plastic substrate coated with said third image forming medium; and impressing a high frequency electric field through each of said photodielectric recording media, plain paper image receiving sheet and each of said image forming media to provide the sublimation of the blue, green and red sublimable dyes, respectively, of said image forming media in selected areas corresponding to the multicolor light image to produce blue, green and red images, respectively, to thereby produce a photographic record of the multicolor image on said plain paper image receiving sheet.