US4962307A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corona discharging device
Assignee: Ricoh Co Ltd
•
Filing: 1989-04-19
•
Granted: 1990-10-09
•
Expires: 2009-04-19
Abstract
Abstract A corona discharging device for an electrophotographic copier, laser printer or similar image forming equipment of the type using an electrophotographic procedure. The device has a corona wire, a rear electrode, and a dielectric plate intervening between the corona wire and the rear electrode. A pulse voltage is applied across the corona wire and rear electrode, while a DC bias voltage is applied across the corona wire and a photoconductive element which is located in close proximity to the corona discharging device. A current for charging the photoconductive element is controlled to a predetermined constant value. When the charging current is lowered below a predetermined value or when the DC bias voltage is increased above a predetermined value or decreased below a predetermined value, a high-tension power supply stops feeding a high voltage by deciding that an output is open or short-circuited.
Inventors
- 👤 Masahide Nakaya
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:38
CPC Classifications
H; H01; H01T; H01T19/00; G; G03; G03G; G03G15/00; G03G15/02; G03G15/0283; G03G15/0291
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
95 words
A corona discharging device for image forming equipment having an image carrier, comprising: a corona discharger located in close proximity to said image carrier and comprising a dielectric plate, a rear electrode positioned at one side of said dielectric plate, and a corona wire positioned at the other side of said dielectric plate; and a high-tension power supply for applying a DC bias voltage across said rear electrode and said image carrier and applying a pulse voltage which is opposite in polarity to the DC bias voltage across said rear electrode and said corona wire.
Claim 2
Dependent Claim
95 words
A corona discharging device for image forming equipment having an image carrier, comprising: a corona discharger located in close proximity to said image carrier and comprising a dielectric plate, a rear electrode positioned at one side of said dielectric plate, and a corona wire positioned at the other side of said dielectric plate; and a high-tension power supply for applying a DC bias voltage across said rear electrode and said image carrier and applying a pulse voltage which is opposite in polarity to the DC bias voltage across said rear electrode and said corona wire.
Claim 3
Dependent Claim
63 words
A device as claimed in claim 1, wherein said high-tension power supply comprises constant current control means for controlling a charging current for charging said image carrier to a predetermined constant current, and high voltage interrupting means for preventing a high voltage from being applied to said corona wire and said rear electrode when the charging current is lowered below a predetermined value.
Claim 4
Dependent Claim
59 words
A device as claimed in claim 1, further comprising: bias voltage sensing means for sensing the DC bias voltage; and high voltage interrupting means for preventing a high voltage from being applied to said corona wire and said rear electrode when the DC bias voltage being sensed by said bias voltage sensing means is increased above a predetermined value.
Claim 5
Dependent Claim
59 words
A device as claimed in claim 2, further comprising bias voltage sensing means for sensing the DC bias voltage, said high voltage interrupting means further preventing a high voltage from being applied to said corona wire and said rear electrode when the DC bias voltage being sensed by said bias voltage sensing means is increased above a predetermined value.
Claim 6
Dependent Claim
19 words
A device as claimed in claim 2, wherein said high voltage interrupting means comprises a load open detection circuit.
Claim 7
Dependent Claim
110 words
A corona discharging device for image forming equipment having an image carrier, comprising: a corona discharger located in close proximity to said image carrier and comprising a dielectric plate, a rear electrode positioned at one side of said dielectric plate, and a corona wire positioned at the other side of said dielectric plate; a high-tension power supply for applying a DC bias voltage across said corona wire and said image carrier and applying a pulse voltage which is opposite in polarity to the DC bias voltage across said rear electrode and said corona wire; and control circuit means for controlling the application of the pulse voltage to said corona discharger.
Claim 8
Dependent Claim
110 words
A corona discharging device for image forming equipment having an image carrier, comprising: a corona discharger located in close proximity to said image carrier and comprising a dielectric plate, a rear electrode positioned at one side of said dielectric plate, and a corona wire positioned at the other side of said dielectric plate; a high-tension power supply for applying a DC bias voltage across said corona wire and said image carrier and applying a pulse voltage which is opposite in polarity to the DC bias voltage across said rear electrode and said corona wire; and control circuit means for controlling the application of the pulse voltage to said corona discharger.
Claim 9
Dependent Claim
63 words
A device as claimed in claim 6, wherein said high-tension power supply comprises: constant current control means for controlling a charging current for charging said image carrier to a predetermined constant current, and high voltage interrupting means for preventing a high voltage from being applied to said corona wire and said rear electrode when the charging current is lowered below a predetermined value.
Claim 10
Dependent Claim
58 words
A device as claimed in claim 6, further comprising: bias voltage sensing means for sensing the DC bias voltage; and high voltage interrupting means for preventing a high voltage from being applied to said corona and said rear electrode when the DC bias voltage being sensed by said bias voltage sensing means is increased above a predetermined value.
Claim 11
Dependent Claim
58 words
A device as claimed in claim 7, further comprising: bias voltage means for sensing the DC bias voltage, said high voltage interrupting means further preventing a high voltage from being applied to said corona wire and said rear electrode when the DC bias voltage being sensed by said bias voltage sensing means is increased above a predetermined value.
Claim 12
Dependent Claim
19 words
A device as claimed in claim 7, wherein said high voltage interrupting means comprises a load open detection circuit.
References Cited (Backward Citations)
US3742237A
Cited
US3961193A
Cited
US4456825A
Cited
US4339783A
Cited
US4446371A
Cited
US4709298A
Cited
US4672505A
Cited
US4700261A
Cited
US4783716A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-08 | 1994-04-09 | 1994-10-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-08 | 1998-04-09 | 1998-10-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-08 | 2002-04-09 | 2002-10-09 | $7700.00 | Window Closed / Lapsed |