Patent US3454298A successfully refreshed from Google Patents.
US3842801A
Expired / Lapsed
US
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Electron radiogram developer with image field screen
Assignee: ELSCINT IMAGING Inc
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Filing: 1972-08-24
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Granted: 1974-10-22
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Expires: 1992-08-24
Abstract
Abstract Apparatus for developing electrostatic images on a receptor sheet by attracting charged toner powder particles to the sheet for subsequent fixing in place. A reduction in the amount of background toner in the visual image is achieved by positioning an image field screen in front of the receptor sheet and maintaining a potential between the screen and the sheet such that the toner is deposited on the sheet only at localities having a charge potential greater than that of the screen.
Inventors
- 👤 R Larson
- 👤 Morsell A Lee
- 👤 E Muntz
- 👤 M Welkowsky
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:58
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0803; Y; Y10; Y10S; Y10S101/00; Y10S101/37
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
164 words
In a powder cloud developer having a developing chamber, means for producing a cloud of charged toner powder particles in the chamber, and means for supporting in the chamber a receptor sheet having an electrostatic image, the improvement comprising in combination: an apertured image field plate mounted in said chamber adjacent said receptor sheet; a charge selection electrode mounted in said chamber, with said particle cloud produced between said plate and electrode; means for producing an electric field between said plate and electrode for attracting particles of one polarity to said electrode and particles of the opposite polarity to said plate, with the charge on said sheet attracting said particles of opposite polarity through the plate apertures to said sheet; a shutter mounted in said chamber between said plate and electrode and adjacent said plate; and means for moving said shutter between a closed position blocking said cloud of particles from said plate and an open position permitting movement of particles to said plate.
Claim 2
Dependent Claim
164 words
In a powder cloud developer having a developing chamber, means for producing a cloud of charged toner powder particles in the chamber, and means for supporting in the chamber a receptor sheet having an electrostatic image, the improvement comprising in combination: an apertured image field plate mounted in said chamber adjacent said receptor sheet; a charge selection electrode mounted in said chamber, with said particle cloud produced between said plate and electrode; means for producing an electric field between said plate and electrode for attracting particles of one polarity to said electrode and particles of the opposite polarity to said plate, with the charge on said sheet attracting said particles of opposite polarity through the plate apertures to said sheet; a shutter mounted in said chamber between said plate and electrode and adjacent said plate; and means for moving said shutter between a closed position blocking said cloud of particles from said plate and an open position permitting movement of particles to said plate.
Claim 3
Dependent Claim
26 words
A developer as defined in claim 1 including means for imparting oscillatory motion to said apertured plate in a plane substantially parallel to said receptor sheet.
Claim 4
Dependent Claim
17 words
A developer as defined in claim 2 wherein said apertured image field plate is a wire screen.
Claim 5
Dependent Claim
36 words
A developer as defined in claim 3 wherein said shutter comprises first and second planar elements positioned adjacent each other when in said first position and moved away from each other when in said second position.
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) | 1977-10-21 | 1978-04-22 | 1978-10-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-21 | 1982-04-22 | 1982-10-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-21 | 1986-04-22 | 1986-10-22 | $7700.00 | Window Closed / Lapsed |