US4468681A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatic record image forming method
Assignee: Fujifilm Business Innovation Corp
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Filing: 1982-01-25
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Granted: 1984-08-28
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Expires: 2002-01-25
Abstract
Abstract The precharging of the surface of an electrostatic recording medium is done sufficiently ahead of the electrode assembly so that all non-uniformities in charge distribution have time to settle out. Preferably, the precharge potential across the recording medium at the electrode assembly differs by no more than approximately 10 volts.
Inventors
- 👤 Shoji Wako
- 👤 Hidemasa Todo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 13:41
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/23; H04N1/29; G; G06; G06K; G06K15/00; G06K15/02; G06K15/14
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
143 words
An electrostatic image forming method comprising the following steps: passing a multi-stylus electrode assembly, having charging electrodes and having auxiliary electrodes covered with an insulating material, over the surface of an electrostatic recording medium during relative movement between said assembly and recording medium at an electrode assembly location, generating a potential between said charging and auxiliary electrodes, precharging said recording medium surface to a precharge potential at a location prior to said assembly along said recording medium, said precharge potential having a non-uniform distribution across said recording medium varying by at least approximately 50%, and controlling the distance L between said precharging location and said electrode assembly location and the speed v of relative movement of said assembly and recording medium for reducing the voltage differential of said preliminary charge across said recording medium surface at said electrode assembly location to approximately 20%.
Claim 2
Dependent Claim
143 words
An electrostatic image forming method comprising the following steps: passing a multi-stylus electrode assembly, having charging electrodes and having auxiliary electrodes covered with an insulating material, over the surface of an electrostatic recording medium during relative movement between said assembly and recording medium at an electrode assembly location, generating a potential between said charging and auxiliary electrodes, precharging said recording medium surface to a precharge potential at a location prior to said assembly along said recording medium, said precharge potential having a non-uniform distribution across said recording medium varying by at least approximately 50%, and controlling the distance L between said precharging location and said electrode assembly location and the speed v of relative movement of said assembly and recording medium for reducing the voltage differential of said preliminary charge across said recording medium surface at said electrode assembly location to approximately 20%.
Claim 3
Dependent Claim
45 words
The method as claimed in claim 1, wherein said recording medium has a surface precharge at said electrode assembly location which differs by no more than approximately 10 volts along a line extending across said medium in a direction substantially parallel to said charging electrodes.
Claim 4
Dependent Claim
25 words
The method as claimed in claim 1 wherein said distance L and speed v are controlled such that (L/v) is greater than approximately 2 seconds.
Claim 5
Dependent Claim
32 words
The method as claimed in claim 1, wherein said precharging step comprises precharging said medium to one polarity and said generating step comprises applying an opposite polarity voltage to said charging electrodes.
References Cited (Backward Citations)
US3527941A
Cited
JPS5138351A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |