Patent US3641981A successfully refreshed from Google Patents.
US3641981A
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Apparatus for controlling developer charge level
Assignee: Xerox Corp
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Filing: 1969-12-24
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Granted: 1972-02-15
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Expires: 1989-12-24
Abstract
Abstract A method and apparatus for controlling the charge on circulating developer material in a development device. A corona discharge device sprays a corona charge onto the developer material to selectively control the charge on the carrier particles during development for enhanced development results.
Inventors
- 👤 Frederick W Hudson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 09:40
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; G03G15/0887; G03G15/0891
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
132 words
Apparatus for developing a surface bearing a latent electrostatic image comprising sump means for supporting a developer for developing said surface including electroscopic toner particles and carrier particles having triboelectrically generated charge of opposite polarity attracting the toner and carrier particles together, circulating means operatively connected to the sump means for movement of the developer past the latent image bearing surface for development of the surface with toner particles stripped from the developer by the latent electrostatic image and charge control means for spraying said developer with electrostatic corona charge while the developer is not moving past the latent image bearing surface including an electrical potential source coupled to the control means to spray charge of a desired polarity onto carrier particles to change the triboelectrically generated potential on the carrier particles.
Claim 2
Dependent Claim
132 words
Apparatus for developing a surface bearing a latent electrostatic image comprising sump means for supporting a developer for developing said surface including electroscopic toner particles and carrier particles having triboelectrically generated charge of opposite polarity attracting the toner and carrier particles together, circulating means operatively connected to the sump means for movement of the developer past the latent image bearing surface for development of the surface with toner particles stripped from the developer by the latent electrostatic image and charge control means for spraying said developer with electrostatic corona charge while the developer is not moving past the latent image bearing surface including an electrical potential source coupled to the control means to spray charge of a desired polarity onto carrier particles to change the triboelectrically generated potential on the carrier particles.
Claim 3
Dependent Claim
27 words
The apparatus of claim 1 wherein said charge control means sprays an electrostatic charge having an opposite polarity than the electrostatic charge possessed by the carrier material.
Claim 4
Dependent Claim
26 words
The apparatus of Claim 1 wherein said charge control means sprays an electrostatic charge having the same polarity as the electrostatic charge possessed by the carrier.
Claim 5
Dependent Claim
21 words
The apparatus of Claim 1 wherein said charge control means sprays an electrostatic charge of both polarities on the carrier material.
Claim 6
Dependent Claim
13 words
The apparatus of Claim 1 wherein said charge control means is a corotron.
Claim 7
Dependent Claim
15 words
The apparatus of claim 5 wherein said corotron is coupled to a negatve electrical potential.
Claim 8
Dependent Claim
15 words
The apparatus of claim 5 wherein said corotron is coupled to an electrical positive potential.
Claim 9
Dependent Claim
15 words
The apparatus of Claim 5 wherein said corotron is coupled to an alternating electrical potential.
Claim 10
Dependent Claim
20 words
The apparatus of Claim 1 wherein said circulating means includes means to cascade the developer past the image bearing surface.
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) | 1975-02-14 | 1975-08-16 | 1976-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-14 | 1979-08-16 | 1980-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-14 | 1983-08-16 | 1984-02-15 | $7700.00 | Window Closed / Lapsed |