US3942080A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for applying a uniform electrostatic charge to electrophotographic film
Assignee: Kimberly Clark Tissue Co
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Filing: 1974-04-05
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Granted: 1976-03-02
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Expires: 1994-04-05
Abstract
Abstract Disclosed are apparatus and method for applying a uniform electrostatic charge to an electrophotographic film through use of a corona discharge electrode positioned close to the film, a high voltage AC potential source connected to the electrode and having a potential greater than the corona threshold potential of the electrode, and a high voltage DC potential source connected to the electrode in series with the AC potential source for biasing the AC potential source, the DC potential source voltage being less than the difference between the voltages of the AC potential source and the corona threshold potential of the electrode. The film is subject to a series of first corona discharges of the desired polarity, of which each discharge is alternated with one of a series of second corona discharges having the opposite polarity and of lesser intensity than the first corona discharges.
Inventors
- 👤 Stephen Mark Milewski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 04:01
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0291; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/102
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
173 words
Apparatus for applying a uniform electrostatic charge to a predetermined portion of an electrophotographic film, comprising: means for grounding the electrophotographic film; a lens module having an opening for charging and imaging the film, the opening being formed by a mask which confines charging of the film to the opening area, each area dimension of the opening being larger than one third of the corresponding dimension within the lens module; a corona discharge electrode positioned within the lens module at a distance from about .2 to about 2.0 inches from the film when the film is placed against the module opening; a high voltage AC potential source connected to the electrode and having a potential greater than the corona threshold potential of the electrode; and a high voltage DC potential source connected to the electrode in series with the AC potential source for biasing the AC potential source, the DC potential source being less than the difference between the voltage of the AC potential source and the corona threshold potential of the electrode.
Claim 2
Dependent Claim
173 words
Apparatus for applying a uniform electrostatic charge to a predetermined portion of an electrophotographic film, comprising: means for grounding the electrophotographic film; a lens module having an opening for charging and imaging the film, the opening being formed by a mask which confines charging of the film to the opening area, each area dimension of the opening being larger than one third of the corresponding dimension within the lens module; a corona discharge electrode positioned within the lens module at a distance from about .2 to about 2.0 inches from the film when the film is placed against the module opening; a high voltage AC potential source connected to the electrode and having a potential greater than the corona threshold potential of the electrode; and a high voltage DC potential source connected to the electrode in series with the AC potential source for biasing the AC potential source, the DC potential source being less than the difference between the voltage of the AC potential source and the corona threshold potential of the electrode.
Claim 3
Dependent Claim
22 words
Apparatus according to claim 1, wherein the corona producing potential is applied between the corona discharge electrode and the grounded electrophotographic film.
Claim 4
Dependent Claim
18 words
Apparatus according to claim 1, wherein the electrode is held stationary with respect to the film during charging.
Claim 5
Dependent Claim
31 words
Apparatus according to claim 1, wherein the electrode is provided by needle, the point of which is positioned during charging in a line perpendicular to the center of the predetermined portion.
Claim 6
Dependent Claim
45 words
Apparatus according to claim 4, further including a lens for focusing an image on the predetermined portion of the film to reproduce the image on the film, and the electrode is positioned on the optical axis of the lens between the lens and the film.
Claim 7
Dependent Claim
232 words
Apparatus for applying a uniform electrostatic charge to a predetermined portion of an electrophotographic film, comprising: means for grounding the electrophotographic film; a lens module including a lens for focusing an image on the predetermined portion of the film to reproduce the image on the film, the lens module having an opening for charging and imaging the film, the opening being formed by a mask which confines charging of the film to the opening area, each area dimension of the opening being larger than one third of the corresponding dimension within the lens module; a corona discharge electrode provided by a needle, the point of which is positioned during charging in a line perpendicular to the center of the predetermined portion and on the optical axis of the lens between the lens and the film at a distance from about .2 to about 2.0 inches from the film when the film is placed against the module opening; a high voltage AC potential source of from about 4.0 to about 10.0 KV connected to the electrode; and a high voltage DC potential source of from about 200 to about 2,000 volts connected to the electrode in series with the AC potential source for biasing the AC potential source, the DC potential source being less than the difference between the voltage of the AC potential source and the corona threshold potential of the electrode.
Claim 8
Dependent Claim
232 words
Apparatus for applying a uniform electrostatic charge to a predetermined portion of an electrophotographic film, comprising: means for grounding the electrophotographic film; a lens module including a lens for focusing an image on the predetermined portion of the film to reproduce the image on the film, the lens module having an opening for charging and imaging the film, the opening being formed by a mask which confines charging of the film to the opening area, each area dimension of the opening being larger than one third of the corresponding dimension within the lens module; a corona discharge electrode provided by a needle, the point of which is positioned during charging in a line perpendicular to the center of the predetermined portion and on the optical axis of the lens between the lens and the film at a distance from about .2 to about 2.0 inches from the film when the film is placed against the module opening; a high voltage AC potential source of from about 4.0 to about 10.0 KV connected to the electrode; and a high voltage DC potential source of from about 200 to about 2,000 volts connected to the electrode in series with the AC potential source for biasing the AC potential source, the DC potential source being less than the difference between the voltage of the AC potential source and the corona threshold potential of the electrode.
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) | 1979-03-02 | 1979-09-01 | 1980-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-02 | 1983-09-01 | 1984-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-02 | 1987-09-01 | 1988-03-02 | $7700.00 | Window Closed / Lapsed |