Patent US3857708A successfully refreshed from Google Patents.
US3857708A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zinc oxide-binder medium containing microscopic cavities
Assignee: Agfa Gevaert NV
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Filing: 1973-03-05
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Granted: 1974-12-31
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Expires: 1993-03-05
Abstract
Abstract Photoconductive zinc oxide particles are contained in an electrically insulating binder medium in the proportion of about 0.5 to 10 to 1, the layer being characterized in that the photoconductive layer is porous and contains myriad interconnected microscopic cavities extending at random throughout the entire layer, said cavities being in direct communication with the ambient atmosphere and with surface areas of photoconductive particles contiguous thereto so that myriad air-photoconductive interfaces exist in said layer.
Inventors
- 👤 K Verhille
- 👤 R Noe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:57
CPC Classifications
G; G03; G03G; G03G5/00; G03G5/02; G03G5/04; G03G5/08; G03G5/087
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
89 words
A PHOTOGRAPHIC MATERIAL SUITABLE FOR ELECTROPHOTOGRAPHIC RECORDING OF INFORMATION COMPRISING A SUPPORT AND A PHOTOCONDUCTIVE INSULATING LAYER CONTAINING FINELY DIVIDED SOLID PHOTOCONDUCTIVE ZINC OXIDE PARTICLES OR AGGLOMERATES THEREOF AND AN ELECTRICALLY INSULATING BINDER MEDIUM IN THE PROPORTION OF ABOUT 0.5-10:1, CHARACTERIZED IN THAT THE PHOTOCONDUCTIVE LAYER IS POROUS AND CONTAINS MYRIAD INTERCONNECTED MICROSCOPIC CAVITIES EXTENDING AT RANDOM THOROUGHOUT THE ENTIRE LAYER, SAID CAVITIES BEING IN DIRECT COMMUNICATION WITH THE AMBIENT ATMOSPHERE AND WITH SURFACE AREAS OF PHOTOCONDUCTIVE PARTICLES CONTIGUOUS THERETO SO THAT MYRIAD AIRPHOTOCONDUCTOR INTERFACES EXIST IN SAID LAYER.
Claim 2
Dependent Claim
89 words
A PHOTOGRAPHIC MATERIAL SUITABLE FOR ELECTROPHOTOGRAPHIC RECORDING OF INFORMATION COMPRISING A SUPPORT AND A PHOTOCONDUCTIVE INSULATING LAYER CONTAINING FINELY DIVIDED SOLID PHOTOCONDUCTIVE ZINC OXIDE PARTICLES OR AGGLOMERATES THEREOF AND AN ELECTRICALLY INSULATING BINDER MEDIUM IN THE PROPORTION OF ABOUT 0.5-10:1, CHARACTERIZED IN THAT THE PHOTOCONDUCTIVE LAYER IS POROUS AND CONTAINS MYRIAD INTERCONNECTED MICROSCOPIC CAVITIES EXTENDING AT RANDOM THOROUGHOUT THE ENTIRE LAYER, SAID CAVITIES BEING IN DIRECT COMMUNICATION WITH THE AMBIENT ATMOSPHERE AND WITH SURFACE AREAS OF PHOTOCONDUCTIVE PARTICLES CONTIGUOUS THERETO SO THAT MYRIAD AIRPHOTOCONDUCTOR INTERFACES EXIST IN SAID LAYER.
Claim 3
Dependent Claim
44 words
A photographic material according to claim 1, wherein the insulating layer contains a mixture of two polymeric binding agents that are substantially incompatible in the solid dry state and that are precipitated on each other from a common solvent wherein they were differently soluble.
Claim 4
Dependent Claim
21 words
A photographic material according to claim 1, wherein the insulating layer contains microscopic cavities of an average width below 20 microns.
Claim 5
Dependent Claim
26 words
A photographic material according to claim 3, wherein the insulating layer contains microscopic cavities with an average width in the range of 2 to 12 microns.
Claim 6
Dependent Claim
17 words
A photographic material according to claim 1, wherein the photoconductive zinc oxide particles have been spectrally sensitized.
Claim 7
Dependent Claim
22 words
A photoconductive material according to claim 1, wherein the photoconductive zinc oxide particles have been treated with a substance increasing their dark-resistivity.
Claim 8
Dependent Claim
17 words
A photoconductive material according to claim 6, wherein said substance is acid butyl phosphate or tetrachlorophthalic anhydride.
Claim 9
Dependent Claim
88 words
A phoTographic material according to claim 1, wherein the binder medium contains at least two polymers characterized by: a. insolubility in water at pH 7, b. differential solubility in the solvent used in the coating of the recording layer without any noticeable turbidity in said solution when applied together in said solvent, c. substantial absence of mutual solubility in the solid state whereby when said polymers are precipitated from a mutual solvent solution they form a polymer mass containing macroscopic heterogeneities, which are detectable by the unaided eye.
Claim 10
Dependent Claim
61 words
A photographic material according to claim 1, wherein the insulating layer contains a polymer selected from the group consisting of polyvinyl acetals, polyvinyl ethers, cellulose ethers, halogen-containing vinyl polymers, chlorinated rubbers and chlorinated polyolefins and a polymer selected from the group consisting of aliphatic esters of polyvinyl alcohol, homopolymers and copolymers of acrylate esters and homopolymers and copolymers of methacrylate esters.
Claim 11
Dependent Claim
24 words
A photographic material according to claim 9, wherein the mixture of polymers consists of a cellulose ether and an aliphatic ester of polyvinyl alcohol.
Claim 12
Dependent Claim
20 words
A photographic material, according to claim 9, wherein an ethyl cellulose ether and a vinyl acetate/vinyl laurate copolymer is used.
Claim 13
Dependent Claim
20 words
A photographic material according to claim 9, wherein an ethyl-allyl cellulose ether and a vinyl acetate/vinyl laurate copolymer is used.
Claim 14
Dependent Claim
25 words
A photographic material according to claim 9, wherein a mixture of polymers is used consisting of a polyvinyl acetal and a vinyl acetate/vinyl laurate copolymer.
Claim 15
Dependent Claim
40 words
A photographic material according to claim 9, wherein a combination of polymers is used consisting of a copolymer of vinyl chloride, vinyl acetate, and a minor amount of a bivalent unsaturated carboxylic acid anhydride and a copolyvinyl acetate/vinyl laurate copolymer.
Claim 16
Dependent Claim
44 words
A photographic material according to claim 9, wherein a mixture of polymers is used consisting of a copolymer of vinyl-chloride, vinylidene chloride, and a minor amount of maleic anhydride and acrylonitrile and a copolymer of vinyl acetate and a C12-C18 carboxylic acid vinylalcohol ester.
Claim 17
Dependent Claim
24 words
A material according to claim 11, wherein the binder contains ethylcellulose and copoly(vinyl acetate/vinyl laurate) (80:20) in a weight ratio of 4:1 to 1:4.
Claim 18
Dependent Claim
17 words
A material according to claim 1, wherein the photoconductive layer is present on a glassine paper support.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |