US3797928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for electrophotography
Assignee: Katsuragawa Electric Co Ltd
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Filing: 1972-11-30
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Granted: 1974-03-19
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Expires: 1992-11-30
Abstract
Abstract In a method of electrophotography comprising the steps of applying a first electric field across a photosensitive element including a photoconductive layer manifesting persisting internal polarization and a highly insulative layer integrally bonded to one side of the photoconductive layer for depositing a charge of one polarity on the surface of the highly insulative layer, and applying a second electric field across the photosensitive element for depositing a charge of the opposite polarity concurrently with projection of a light image upon the photoconductive layer whereby to form a latent image on the surface of the highly insulative layer corresponding to the light image, a third electric field is applied across the photosensitive element for depositing a charge of the same polarity as the charge deposited by the second electric field for improving the contrast and then the latent image is developed to provide a visible image.
Inventors
- 👤 K Kinoshita
- 👤 M Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:36
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/056
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
184 words
An electrophotographic apparatus comprising a photosensitive element including a photoconductive layer manifesting persistent internal polarization and a highly insulative layer integrally bonded to one side of said photoconductive layer; a first corona discharge unit for depositing a charge of one polarity on the surface of said highly insulative layer; a second corona discharge unit for depositing a second charge of the opposite polarity on the surface of said highly insulative layer; an optical system for projecting a light image upon said photoconductive layer concurrently with the application of said charge of the opposite polarity by said second corona discharge unit whereby to form a latent image on said highly insulative layer corresponding to said light image; a third corona discharge unit for depositing a third charge of the same polarity as said second charge whereby to increase the potential difference of said latent image between portions corresponding to the bright and dark portions of said light image; an insulative receiptor material; means for transfer printing said latent image onto said receiptor material; and means for developing said latent image transferred onto said receiptor material.
Claim 2
Dependent Claim
184 words
An electrophotographic apparatus comprising a photosensitive element including a photoconductive layer manifesting persistent internal polarization and a highly insulative layer integrally bonded to one side of said photoconductive layer; a first corona discharge unit for depositing a charge of one polarity on the surface of said highly insulative layer; a second corona discharge unit for depositing a second charge of the opposite polarity on the surface of said highly insulative layer; an optical system for projecting a light image upon said photoconductive layer concurrently with the application of said charge of the opposite polarity by said second corona discharge unit whereby to form a latent image on said highly insulative layer corresponding to said light image; a third corona discharge unit for depositing a third charge of the same polarity as said second charge whereby to increase the potential difference of said latent image between portions corresponding to the bright and dark portions of said light image; an insulative receiptor material; means for transfer printing said latent image onto said receiptor material; and means for developing said latent image transferred onto said receiptor material.
Claim 3
Dependent Claim
62 words
The apparatus according to claim 1 wherein said photosensitive element is wrapped around the periphery of a rotary drum, said first, second and third corona discharge units and said transfer printing means are disposed about the periphery of said rotary drum in the order mentioned, and said optical system is disposed to project said light image through said second corona discharge unit.
Claim 4
Dependent Claim
33 words
The apparatus according to claim 1 which further comprises a source of light positioned between said third corona discharge unit and said transfer printing means for irradiating said latent image with uniform light.
Claim 5
Dependent Claim
84 words
The apparatus according to claim 1 wherein said second and third corona discharge unit is combined into an integral unit comprising an inverted cup shaped counter electrode, and a corona discharge electrode contained in said counter electrode and takes the form of metal wires arranged in parallel with the top wall of said counter electrode and applied with the same potential, said top wall of said counter electrode being provided with a window to project said light image through metal wires underlying said window.
Claim 6
Dependent Claim
104 words
The apparatus according to claim 1 wherein said second corona discharge unit comprises a cylindrical counter electrode and a corona discharge electrode contained in said counter electrode, said counter electrode serving to project said light image through said corona discharge electrode, wherein said third corona discharge unit comprises an inverted cup shaped counter electrode and a corona discharge electrode disposed in said cup shaped counter electrode and wherein said corona discharge electrode of said third corona discharge unit is supplied with a potential having the same polarity but higher than the potential applied to the corona discharge electrode of said second corona discharge unit.
Claim 7
Dependent Claim
37 words
The apparatus according to claim 2 wherein said transfer printing roller is rotated at the same peripheral speed as said rotary drum and said transfer printing roller and said rotary drum are maintained at the same potential.
References Cited (Backward Citations)
US3615395A
Cited
US3609031A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-18 | 1977-09-17 | 1978-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-18 | 1981-09-17 | 1982-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-18 | 1985-09-17 | 1986-03-19 | $7700.00 | Window Closed / Lapsed |