US3783283A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corona charging device with semiconductive shield
Assignee: Unisys Corp
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Filing: 1972-09-26
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Granted: 1974-01-01
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Expires: 1992-09-26
Abstract
Abstract A corona charging device, suitable for imparting an electrostatic charge to a photoconductive surface, comprises a corona discharge electrode having a high voltage applied thereto, and a grounded semiconductive shield partially surrounding the electrode. As compared to prior art conductive shields, the semiconductive shield results in a more efficient charging device since less of the corona ion current flows to the shield. It also permits charging of the photoconductive surface to a higher voltage than prior art devices without the occurrence of arcing, and if arcing does occur it takes place between the electrode and the shield rather than between the electrode and the photoconductive surface.
Inventors
- 👤 D Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 08:42
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0291
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
103 words
In a corona charging device wherein relative movement between a photoconductive surface and an elongated corona discharge electrode means in close proximity thereto takes place as a high voltage is applied to said electrode means to cause a corona discharge, said electrode means being positioned parallel to said surface and extending transverse to said movement, the improvement comprising an elongated shield of semiconductive material partially surrounding said electrode means and extending parallel thereto, said shield having an elongated slit extending transverse to the direction of said relative movement to permit the flow of corona current from said electrode means to said photoconductive surface.
Claim 2
Dependent Claim
103 words
In a corona charging device wherein relative movement between a photoconductive surface and an elongated corona discharge electrode means in close proximity thereto takes place as a high voltage is applied to said electrode means to cause a corona discharge, said electrode means being positioned parallel to said surface and extending transverse to said movement, the improvement comprising an elongated shield of semiconductive material partially surrounding said electrode means and extending parallel thereto, said shield having an elongated slit extending transverse to the direction of said relative movement to permit the flow of corona current from said electrode means to said photoconductive surface.
Claim 3
Dependent Claim
25 words
The improvement as claimed in claim 1 wherein said shield is made of a material having a resistivity in the range of 103 to 109ohm-cm.
Claim 4
Dependent Claim
39 words
The improvement as claimed in claim 1 wherein said photoconductive surface is composed of a material having a dark resistivity of approximately 1014ohm-cm., said shield comprising a material having a resistivity in the range of approximately 103 to 109ohm-cm.
Claim 5
Dependent Claim
48 words
The improvement as claimed in claim 1 wherein said photoconductive surface is comprised of a photoconductive material disposed in a layer over a conductive substrate, said semiconductive shield and said substrate being connected to ground potential, and said electrode means is connected to a source of unidirectional voltage.
Claim 6
Dependent Claim
42 words
The improvement as claimed in claim 1 wherein said semiconductive shield is composed of a material having a resistivity in the range of 103 to 109ohm-cm., and said photoconductive material has a dark resistivity greater than the resistivity of said shield material.
Claim 7
Dependent Claim
14 words
The improvement as claimed in claim 5 wherein said photoconductive material is vitreous selenium.
Claim 8
Dependent Claim
16 words
The combination as claimed in claim 6 wherein said shield material is a carbon impregnated plastic.
Claim 9
Dependent Claim
16 words
The improvement as claimed in claim 1 wherein said semiconductive shield material has a fixed resistivity.
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) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |