US3908164A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Corona current measurement and control arrangement
Assignee: Xerox Corp
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Filing: 1974-10-03
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Granted: 1975-09-23
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Expires: 1994-10-03
Abstract
Abstract Apparatus is disclosed in accordance with the teachings of the present invention for obtaining a true measurement of charging current supplied by a corona discharge device to a charge receiving surface. According to the invention, a bridge circuit is formed which includes the corona device as one arm and a first resistor connected in the current return path from the corona device to a power supply as another arm thereof. The remaining arms of the bridge include a capacitor and a resistor connected in series with each other across the source to complete the bridge and provide the signal required to compensate for reactive current through the corona device. The bridge is first brought into balance with the power supply below corona onset voltage, then when the power supply is increased above the corona outset voltage the bridge output potential is used as a feedback signal to maintain the corona current constant. The bridge output may also be used in determining the true corona charging current.
Inventors
- 👤 Delmer G Parker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:18
CPC Classifications
G; G05; G05F; G05F1/00; G05F1/10; G05F1/46; G01; G01R; G01R17/00; G01R17/10; G01R29/00; G01R29/24; G03; G03G; G03G15/00; G03G15/02; G03G15/0266; G03G15/0291
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
164 words
A bridge circuit for measuring the corona charging current deposited by an A.C. corona discharge device on a charge collecting surface, said corona device including an electrode spaced from said surface, said bridge having power input nodes and sensing nodes comprising an A.C. voltage source coupled to said input nodes, a first resistor coupled in series with said device across said input nodes to form a first current path, a capacitor and a second resistor connected in series across said input nodes to form a second current path in parallel with said first current path across said source, means coupled to said sensing nodes for measuring the output of said bridge, and, means for balancing said bridge when the output of said source is below the corona onset value whereby when the voltage of said source is raised above the corona onset potential, said corona charging current may be determined from the measured value of said imbalance and the value of said first resistor.
Claim 2
Dependent Claim
164 words
A bridge circuit for measuring the corona charging current deposited by an A.C. corona discharge device on a charge collecting surface, said corona device including an electrode spaced from said surface, said bridge having power input nodes and sensing nodes comprising an A.C. voltage source coupled to said input nodes, a first resistor coupled in series with said device across said input nodes to form a first current path, a capacitor and a second resistor connected in series across said input nodes to form a second current path in parallel with said first current path across said source, means coupled to said sensing nodes for measuring the output of said bridge, and, means for balancing said bridge when the output of said source is below the corona onset value whereby when the voltage of said source is raised above the corona onset potential, said corona charging current may be determined from the measured value of said imbalance and the value of said first resistor.
Claim 3
Dependent Claim
37 words
The combination recited in claim 1 wherein said source is a variable source and further including means coupled to said sensing nodes for providing a control signal to adjust said source in response to said bridge imbalance.
Claim 4
Dependent Claim
23 words
The combination recited in claim 1 wherein said second current path has an impedence which is much greater than said first current path.
Claim 5
Independent Claim
144 words
A method of holding constant the corona charging current output of an A.C. corona discharge device comprising forming an electrical bridge having input nodes and ouput nodes, said bridge including said device and a first resistor in series with each other across said input nodes, and a capacitor and second resistor in series with each other connected across said input nodes, said capacitor and corona device forming adjacent arms of the bridge, coupling a variable A.C. voltage to said input nodes, adjusting said source to a value below the corona onset potential, adjusting said bridge to a balanced condition at which the voltage across said output nodes is at a minimum, re-adjusting said source to a value above the corona onset potential to thereby generate an imbalance voltage across said output nodes, and thereafter continuously adjusting said source to maintain said imbalance voltage constant.
Claim 6
Independent Claim
144 words
A method of holding constant the corona charging current output of an A.C. corona discharge device comprising forming an electrical bridge having input nodes and ouput nodes, said bridge including said device and a first resistor in series with each other across said input nodes, and a capacitor and second resistor in series with each other connected across said input nodes, said capacitor and corona device forming adjacent arms of the bridge, coupling a variable A.C. voltage to said input nodes, adjusting said source to a value below the corona onset potential, adjusting said bridge to a balanced condition at which the voltage across said output nodes is at a minimum, re-adjusting said source to a value above the corona onset potential to thereby generate an imbalance voltage across said output nodes, and thereafter continuously adjusting said source to maintain said imbalance voltage constant.
Claim 7
Dependent Claim
45 words
The method recited in claim 4 wherein said device is selected to include an electrode spaced from a charge collecting surface, and said first resistance is selected to be small relative to the impedence of the inherent capacity exhibited between said electrode and said surface.
References Cited (Backward Citations)
US3604925A
Cited
US3763410A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-22 | 1979-03-24 | 1979-09-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-22 | 1983-03-24 | 1983-09-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-22 | 1987-03-24 | 1987-09-23 | $7700.00 | Window Closed / Lapsed |