Patent US4331756A successfully refreshed from Google Patents.
US4331756A
Expired / Lapsed
US
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Developer compositions with toner, coated carrier and lubricant
Assignee: Ricoh Co Ltd
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Filing: 1980-11-04
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Granted: 1982-05-25
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Expires: 2000-11-04
Abstract
Abstract Electrophotographic developer compositions containing carrier, toner and special purpose additives such as flow promoters, dry lubricants and the like are prepared by coating carrier particles with a coating selected so that the triboelectric relationship between the surface of the carrier and the surface of the additive is substantially zero.
Inventors
- 👤 Edward F. Mayer
- 👤 Arthur S. Diamond
- 👤 Paul Chang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:25
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1135; G03G9/103; G03G9/1133
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
72 words
An electrophotographic developer composition comprising coated carrier particles together with toner particles, the concentration of the toner particles being from 5 to 75 g/Kg of carrier particles, and a lubricant additive, the concentration of the lubricant additive being from 0.5 to 1.5% by weight, based on the weight of the toner particles, the surface triboelectric relationship between the surface of the carrier and the surface of the lubricant additive being substantially zero.
Claim 2
Dependent Claim
72 words
An electrophotographic developer composition comprising coated carrier particles together with toner particles, the concentration of the toner particles being from 5 to 75 g/Kg of carrier particles, and a lubricant additive, the concentration of the lubricant additive being from 0.5 to 1.5% by weight, based on the weight of the toner particles, the surface triboelectric relationship between the surface of the carrier and the surface of the lubricant additive being substantially zero.
Claim 3
Dependent Claim
41 words
An electrophotographic developer composition of claim 1 wherein the carrier particles are coated with a miscible mixture of a butadiene-acrylonitrile rubber containing from 20% to 40% by weight acrylonitrile, together with a polyurethane elastomer, said mixture being soluble in organic solvents.
Claim 4
Dependent Claim
14 words
An electrophotographic developer composition of claim 1 wherein the lubricant is a fluorohydrocarbon polymer.
Claim 5
Dependent Claim
14 words
An electrophotographic developer composition of claim 3 wherein the fluorohydrocarbon polymer is a polytetrafluoroethylene.
Claim 6
Dependent Claim
13 words
An electrophotographic developer composition of claim 1 wherein the lubricant is zinc stearate.
Claim 7
Dependent Claim
50 words
An electrophotographic developer composition of claim 5 wherein the carrier particles are coated with a miscible mixture comprising 20% by weight of a butadiene-acrylonitrile rubber containing from about 20% to 40% by weight acrylonitrile together with 80% by weight of a polyurethane elastomer, said mixture being soluble in organic solvents.
Claim 8
Dependent Claim
147 words
In an electrophotographic process wherein a visible image is produced by depositing toner particles from an electrophotographic composition on to a latent electrostatic image, said developer composition comprising coated carrier particles together with toner particles, the concentration of the toner particles being from 5 to 75 g/Kg of carrier particles; and a lubricant additive, the concentration of the lubricant additive being from 0.05% to 1.5% by weight, based on the weight of the toner particles, in which process the toner and the additive are replenished from time to time during the practice of the process, the improvement of maintaining the weight ratio of toner particles to lubricant substantially constant while the toner and the lubricant are being utilized to form visible images and replenished from time to time by employing coated carrier particles and a lubricant additive between which the triboelectric relationship is substantially equal to zero.
Claim 9
Dependent Claim
147 words
In an electrophotographic process wherein a visible image is produced by depositing toner particles from an electrophotographic composition on to a latent electrostatic image, said developer composition comprising coated carrier particles together with toner particles, the concentration of the toner particles being from 5 to 75 g/Kg of carrier particles; and a lubricant additive, the concentration of the lubricant additive being from 0.05% to 1.5% by weight, based on the weight of the toner particles, in which process the toner and the additive are replenished from time to time during the practice of the process, the improvement of maintaining the weight ratio of toner particles to lubricant substantially constant while the toner and the lubricant are being utilized to form visible images and replenished from time to time by employing coated carrier particles and a lubricant additive between which the triboelectric relationship is substantially equal to zero.
Claim 10
Dependent Claim
13 words
A process as in claim 7 wherein the lubricant is a fluorohydrocarbon polymer.
Claim 11
Dependent Claim
13 words
A process as in claim 8 wherein the fluorohydrocarbon polymer is a polytetrafluoroethylene.
Claim 12
Dependent Claim
40 words
A process as in claim 7 wherein the carrier particles are coated with a miscible mixture of butadiene-acrylonitrile rubber containing from about 20% to 40% by weight acrylonitrile together with a polyurethane elastomer, said mixture being soluble in organic solvents.
Claim 13
Dependent Claim
12 words
A process as in claim 7 wherein the lubricant is zinc stearate.
Claim 14
Dependent Claim
50 words
A process as in claim 11 wherein the carrier particles are coated with a miscible mixture comprising 20% by weight of a butadiene-acrylonitrile rubber containing from about 20% to 40% by weight acrylonitrile together with 80% by weight of a polyurethane elastomer, said mixture being soluble in polar organic solvents.
References Cited (Backward Citations)
US3798167A
Cited
US3983045A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-05-24 | 1985-11-23 | 1986-05-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-05-24 | 1989-11-23 | 1990-05-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-05-24 | 1993-11-23 | 1994-05-25 | $7700.00 | Window Closed / Lapsed |