US3802880A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoconductive zinc oxide coating containing calcined clay
Assignee: Westvaco Corp
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Filing: 1972-05-31
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Granted: 1974-04-09
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Expires: 1992-05-31
Abstract
Abstract An economical and improved photoconducting coating for an electrophotographic paper is disclosed which contains photoconductive zinc oxide dispersed in an insulating binder and applied to an electroconductive base sheet wherein the photoconducting coating includes as an extender for the photoconductive zinc oxide a low cost nonconductive white pigmentary material selected from the group consisting of ground naturally occurring calcium carbonates, precipitated calcium carbonates, calcined clays having no additional treatment, or calcined clays treated to make them organophilic.
Inventors
- 👤 J Holden
- 👤 F Mellows
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 20:36
CPC Classifications
G; G03; G03G; G03G5/00; G03G5/02; G03G5/04; G03G5/05; G03G5/0503; G03G5/0507
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
34 words
The electrophotographic recording element of claim 1 wherein the photoconducting insulating layer comprises by weight not more that 25 percent of the calcined clay material based on the weight of the photoconductive zinc oxide.
Claim 2
Dependent Claim
31 words
The electrophotographic recording element of claim 2 wherein the photoconducting insulating layer also comprises up to 3 percent addition of a polyvinyl ether wax having an acid value of from 72-76.
Claim 3
Dependent Claim
163 words
An electrophotographic recording element consisting of an electroconductive base material carrying a photoconducting insulating layer, said layer comprising an electrically insulating film forming binder and suspended in said film forming binder a mixture of photoconductive zinc oxide and a nonphotoconductive white pigmentary material, said nonphotoconductive pigmentary material being characterized as a good electrical insulator with the ability to dissipate an electrostatic charge and as having a water content not greater that 0.5 percent by volume and as being nonhydrophilic wherein said photoconducting insulating layer comprises at least 75 percent by weight of photoconductive zinc oxide and up to 25 percent by weight of the nonphotoconductive white pigmentary material based on the weight of the zinc oxide characterized in that the nonphotoconductive white pigmentary material consists of from 0 to 12- 1/2 percent of a ground, naturally occurring calcium carbonate material of a particle size of between 1.6 and 2.5 microns and from 25 to 12- 1/2 percent of an untreated calcined clay material.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-04-08 | 1977-10-08 | 1978-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-04-08 | 1981-10-08 | 1982-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-04-08 | 1985-10-08 | 1986-04-09 | $7700.00 | Window Closed / Lapsed |