US4408865A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corona discharge device for electrophotographic charging and potential leveling
Assignee: HP Inc
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Filing: 1981-11-23
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Granted: 1983-10-11
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Expires: 2001-11-23
Abstract
Abstract A corona discharge device for electrophotographic printing is provided in which erasing and primary charging functions are performed by a single device. A screened charging arrangement is used for ion steering, while simultaneous illumination by light produces charge carriers in the photoconducting layer of the drum. In one embodiment, a photochemically etched stainless steel screen is used.
Inventors
- 👤 Thomas Camis
- 👤 Paul R. Spencer
- 👤 Erwin H. Schwiebert
- 👤 Robert R. Hay
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:39
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/22; G03G15/24; G03G15/02; G03G15/0291; G03G21/00; G03G21/0094
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
120 words
A corona discharge device for simultaneous potential leveling and uniform primary charging to a desired drum potential of a rotating photoreceptor drum of an electro-photographic printing device comprising: a shield; a plurality of corona wires within the shield, all of the corona wires being connected to receive a positive d.c. voltage, for producing positive ions; a screen mounted on the shield for steering said positive ions toward said photoreceptor drum for charging said photoreceptor drum, the screen and the shield being maintained at a potential below the desired drum potential; and a continuously illuminating light source for illuminating a first portion of said photoreceptor drum while said first portion of said photoreceptor drum is being charged by said positive ions.
Claim 2
Dependent Claim
120 words
A corona discharge device for simultaneous potential leveling and uniform primary charging to a desired drum potential of a rotating photoreceptor drum of an electro-photographic printing device comprising: a shield; a plurality of corona wires within the shield, all of the corona wires being connected to receive a positive d.c. voltage, for producing positive ions; a screen mounted on the shield for steering said positive ions toward said photoreceptor drum for charging said photoreceptor drum, the screen and the shield being maintained at a potential below the desired drum potential; and a continuously illuminating light source for illuminating a first portion of said photoreceptor drum while said first portion of said photoreceptor drum is being charged by said positive ions.
Claim 3
Dependent Claim
17 words
A corona discharge device as in claim 1 wherein said screen is a photochemically etched steel sheet.
Claim 4
Dependent Claim
36 words
A corona discharge device as in claims 1 or 2 wherein said light source is positioned so that light from said source passes between said corona wires and through said screen before reaching said photoreceptor drum.
Claim 5
Dependent Claim
41 words
A corona discharge device as in claim 3 wherein said light source is positioned so that a second portion of said photoreceptor drum is not illuminated while said second portion of said photoreceptor drum is being charged by said positive ions.
Claim 6
Dependent Claim
16 words
A corona discharge device as in claim 1 wherein said screen is a fineblanked steel sheet.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-10-10 | 1987-04-11 | 1987-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-10 | 1991-04-11 | 1991-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-10 | 1995-04-11 | 1995-10-11 | $7700.00 | Window Closed / Lapsed |