Patent US4484812A successfully refreshed from Google Patents.
US4484812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic charging system for electrophotographic copying machine
Assignee: Fujifilm Business Innovation Corp
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Filing: 1983-02-07
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Granted: 1984-11-27
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Expires: 2003-02-07
Abstract
Abstract An electrostatic charging system for an electrophotographic copying machine comprises a photoreceptor, electrostatic charger, an a.c. high voltage transformer for driving the electrostatic charger and a photoreceptor current detector. The transformer is enclosed with a conductive casing insulated from ground and one output of the secondary winding of the transformer is connected to the casing so that leakage current generated in the transformer is subjected to be fed back to the transformer itself through the conductive casing, avoiding the leakage current to flow into the photoreceptor current detector, whereby photoreceptor current can be detected with accuracy.
Inventors
- 👤 Hiroshi Takayanagi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:56
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0266
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
120 words
An electrostatic charging system for an electrophotographic copying machine comprising: a photoreceptor having a photoconductive layer placed on a conductive substrate connected to a grounded conductive frame, electrostatic charging means disposed in the vicinity of said photoreceptor, an a.c. high voltage power transformer for driving said electrostatic charging means, one end of the secondary winding of said transformer being connected to said electrostatic charging means, a current detector connected between the other end of the secondary winding of said transformer and said conductive frame, a conductive housing insulated from said conductive frame and enclosing said a.c. high voltage power transformer, and connecting means for connecting said conducting housing to said the other end of the secondary winding of said transformer.
Claim 2
Dependent Claim
120 words
An electrostatic charging system for an electrophotographic copying machine comprising: a photoreceptor having a photoconductive layer placed on a conductive substrate connected to a grounded conductive frame, electrostatic charging means disposed in the vicinity of said photoreceptor, an a.c. high voltage power transformer for driving said electrostatic charging means, one end of the secondary winding of said transformer being connected to said electrostatic charging means, a current detector connected between the other end of the secondary winding of said transformer and said conductive frame, a conductive housing insulated from said conductive frame and enclosing said a.c. high voltage power transformer, and connecting means for connecting said conducting housing to said the other end of the secondary winding of said transformer.
Claim 3
Dependent Claim
39 words
An electrostatic charging system as defined in claim 1 wherein said electrostatic charging means is a corona discharger, a shielding case of said corona discharger being connected to said the other end of the secondary winding of said transformer.
Claim 4
Dependent Claim
35 words
An electrostatic charging system as defined in claim 1 wherein said current detector comprises a current detection resistor connected between said the other end of the secondary winding of said transformer and said conductive frame.
Claim 5
Dependent Claim
25 words
An electrostatic charging system as defined in claim 1 wherein said conductive housing is insulated from said conductive frame by inserting an insulating board therebetween.
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) | 1987-11-27 | 1988-05-28 | 1988-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-27 | 1992-05-28 | 1992-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-27 | 1996-05-28 | 1996-11-27 | $7700.00 | Window Closed / Lapsed |