US4647186A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Biased scavenging grid for electrographic apparatus
Assignee: Eastman Kodak Co
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Filing: 1985-11-04
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Granted: 1987-03-03
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Expires: 2005-11-04
Abstract
Abstract Disclosed is apparatus for scavenging charged particles (e.g. triboelectrically carrier particles) from an electrographic recording element. Such apparatus comprises a conductive grid positioned in close proximity to the path of the recording element, and biasing means for electrically biasing the grid so as to attract the charged particles from the recording element yet prevent them from depositing on, and thereby contaminating, the grid.
Inventors
- 👤 Timothy G. Armstrong
- 👤 Arthur S. Kroll
- 👤 Frank A. Shuster
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:14
CPC Classifications
G; G03; G03G; G03G21/00; G03G21/0005; G03G21/0047; G03G15/00; G03G15/06; G03G15/08; G03G15/095
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
72 words
Apparatus for scavenging undesired charged particles from the surface of a moving electrographic recording element, said apparatus comprising (a) a scavenging grid comprising a plurality of spaced, electrically conductive, non-magnetic wires, said grid being positioned in close proximity path of movement of the recording element; and (b) means for electrically biasing the grid wires to attract the particles from the recording element while preventing the accumulation of such particles on the grid.
Claim 2
Dependent Claim
72 words
Apparatus for scavenging undesired charged particles from the surface of a moving electrographic recording element, said apparatus comprising (a) a scavenging grid comprising a plurality of spaced, electrically conductive, non-magnetic wires, said grid being positioned in close proximity path of movement of the recording element; and (b) means for electrically biasing the grid wires to attract the particles from the recording element while preventing the accumulation of such particles on the grid.
Claim 3
Dependent Claim
15 words
The apparatus according to claim 1 wherein said biasing means comprising an AC power source.
Claim 4
Dependent Claim
23 words
Apparatus according to claim 2 wherein said AC power source has a frequency within the range of about 200 to about 600 hertz.
Claim 5
Dependent Claim
21 words
Apparatus according to claim 2 wherein said AC voltage source has a peak-to-peak voltage of between about 400 and 700 volts.
Claim 6
Dependent Claim
45 words
Apparatus according to claim 2 wherein said biasing means further comprises a DC source having a polarity opposite that of the particles, and a level such that, during a portion of the AC cycle, the grid is biased to the same polarity as the particles.
Claim 7
Dependent Claim
29 words
Apparatus according to claim 4 wherein said AC voltage source has a peak-to-peak voltage of about 600 volts, and wherein said DC source has a voltage of about 200.
Claim 8
Dependent Claim
100 words
In apparatus for developing an electrostatic image on an electrographic recording element, such apparatus comprising applicator means for applying a two-component electrographic developer to the recording element to render said image visible, said developer comprising oppositely charged toner and carrier particles, the improvement comprising scavenging means for removing charged carrier particles from the recording element, such carrier particles being inadvertently applied to the recording element during development of the electrostatic image, said scavenging means comprising a conductive grid positioned in close proximity to said recording element, and means for electrically biasing the grid to alternately attract and repel carrier particles.
Claim 9
Dependent Claim
100 words
In apparatus for developing an electrostatic image on an electrographic recording element, such apparatus comprising applicator means for applying a two-component electrographic developer to the recording element to render said image visible, said developer comprising oppositely charged toner and carrier particles, the improvement comprising scavenging means for removing charged carrier particles from the recording element, such carrier particles being inadvertently applied to the recording element during development of the electrostatic image, said scavenging means comprising a conductive grid positioned in close proximity to said recording element, and means for electrically biasing the grid to alternately attract and repel carrier particles.
Claim 10
Dependent Claim
40 words
Apparatus according to claim 7 wherein the biasing means comprising a DC-biased AC power source, such bias being insufficient to prevent the AC bias signal from having the same polarity as the carrier particles during a portion of its cycle.
Claim 11
Dependent Claim
23 words
Apparatus according to claim 8 wherein the frequency of the AC source is within the range of about 200 to about 600 hertz.
Claim 12
Dependent Claim
25 words
Apparatus according to claim 7 further comprising means for vibrating said grid to minimize any tendency for the scavenged particles to adhere to said grid.
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) | 1990-03-02 | 1990-09-01 | 1991-03-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-03-02 | 1994-09-01 | 1995-03-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-03-02 | 1998-09-01 | 1999-03-03 | $7700.00 | Window Closed / Lapsed |