US3657091A
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Electrophoretic imaging method employing a periodic electric field
Assignee: Xerox Corp
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Filing: 1968-10-03
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Granted: 1972-04-18
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Expires: 1988-10-03
Abstract
Abstract Method and apparatus for improving image density, contrast and quality and photographic speed in an electrophoretic imaging system utilizing a particulate suspension for forming the image. The method and apparatus stress a thin layer of the electrophoretic suspension of particles in a carrier on an electrode during imaging by applying a high frequency pulsed or varying electric field across the imaging suspension.
Inventors
- 👤 Edward Forest
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:15
CPC Classifications
G; G03; G03G; G03G17/00; G03G17/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
52 words
The method of claim 1 wherein the steps of exposing and periodic applying of an electric field occur simultaneously and the frequency of the periodic application of the field is at a rate such that the field is applied when the electrodes are in contact with the suspension at contiguous portions thereof.
Claim 2
Dependent Claim
25 words
The method of claim 1 wherein application of the field is such that the period is cyclic and the wave form approximates a square wave.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein the application of the field is such that the period is cyclic and the wave form thereof is at least a portion of a sine wave.
Claim 4
Dependent Claim
21 words
The method of claim 3 or 4 wherein the duty time of the cycle is 50 percent of the cycle time.
Claim 5
Dependent Claim
23 words
The method of claim 3 or 4 wherein the duty time of the cycle is less than 50 percent of the cycle time.
Claim 6
Dependent Claim
22 words
The method of claim 3 or 4 wherein the duty time of the cycle is greater than 50 percent of the cycle.
Claim 7
Dependent Claim
95 words
In a method for imaging electrophoretic particle suspensions having a first electrode adapted to support an image formed from the suspension, at least another electrode for contacting the suspension such that it is maintained between said electrodes, including applying an electric field across the suspension between the first and the other electrodes, and exposing the suspension to an image with activating electromagnetic radiation the improvement including periodically varying the electric field across the suspension, said variation being of such a direction and amplitude as to remain above the threshold potential for forming an image electrophoretically.
Claim 8
Dependent Claim
16 words
The method of claim 8 wherein said periodic varying of potential is of a constant frequency.
Claim 9
Dependent Claim
15 words
The method of claim 8 wherein said periodic varying potential has a constant peak amplitude.
Claim 10
Dependent Claim
16 words
The method of claim 8 wherein said periodic varying potential includes a positive and negative amplitude.
Claim 11
Dependent Claim
28 words
The method of claim 8 wherein said periodic varying potential includes a rectified amplitude having a potential substantially only in a direction additive to the applied electric field.
Claim 12
Dependent Claim
19 words
The method of claim 8 wherein the frequency of the periodic varied field is capable of itself being varied.
Claim 13
Dependent Claim
24 words
The method of claim 9 wherein the frequency is such that its effect on the image is greater than five line pairs per millimeter.
Claim 14
Dependent Claim
21 words
The method of claim 1 including causing relative movement at a predetermined velocity between the first electrode and the other 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) | 1975-04-18 | 1975-10-18 | 1976-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-18 | 1979-10-18 | 1980-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-18 | 1983-10-18 | 1984-04-18 | $7700.00 | Window Closed / Lapsed |