US3797927A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic copying machine
Assignee: Canon Inc
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Filing: 1972-05-15
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Granted: 1974-03-19
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Expires: 1992-05-15
Abstract
Abstract An improvement of an electrophotographic copying machine is provided in which a plurality of grounded grid electrodes are interposed between image forming means and surface of a photosensitive member of the type comprising an electrically conducting support, a photoconductive layer and an insulating layer, wherein the image forming means includes a device for focusing a light image and simultaneously discharging the charged surface of the insulating layer. The perfect discharge of the surface of the photosensitive member can be attained with this apparatus an image having a high contrast, excellent tone reproducibility and uniform sensitivity may be reproduced without being adversely affected by the environmental conditions.
Inventors
- 👤 T Takahashi
- 👤 Y Ito
- 👤 H Kodowaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:11
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0291
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
126 words
An electrophotographic copying machine comprising a photosensitive member having an insulating surface; a first charger means for uniformly imparting a first charge upon the surface of said photosensitive member; simultaneous-light-image-projection-and-discharge means for projecting a light image of an object to be copied upon the surface of said photosensitive member and simultaneously imparting a second charge to discharge said first charge imparted by said first charger means, said simultaneous-lightimage-projection-and-discharge means comprising corona discharge electrodes, auxiliary electrodes surrounding said corona discharge electrodes and defining an optical aperture and an opening for discharge, and means for equalizing the surface charges including grounded grid electrodes disposed in the proximity of said discharge opening defined by said auxiliary electrodes; and means for blanket exposing the whole surface of said photosensitive member.
Claim 2
Dependent Claim
126 words
An electrophotographic copying machine comprising a photosensitive member having an insulating surface; a first charger means for uniformly imparting a first charge upon the surface of said photosensitive member; simultaneous-light-image-projection-and-discharge means for projecting a light image of an object to be copied upon the surface of said photosensitive member and simultaneously imparting a second charge to discharge said first charge imparted by said first charger means, said simultaneous-lightimage-projection-and-discharge means comprising corona discharge electrodes, auxiliary electrodes surrounding said corona discharge electrodes and defining an optical aperture and an opening for discharge, and means for equalizing the surface charges including grounded grid electrodes disposed in the proximity of said discharge opening defined by said auxiliary electrodes; and means for blanket exposing the whole surface of said photosensitive member.
Claim 3
Dependent Claim
24 words
An electrophotographic copying machine as set forth in claim 1 wherein said auxiliary electrodes are made of an electrically conducting material and are grounded.
Claim 4
Dependent Claim
20 words
An electrophotographic copying machine as set forth in claim 1 wherein said grid electrodes comprise a plurality of wire electrodes.
Claim 5
Dependent Claim
37 words
An electrophotographic copying machine as set forth in claim 1 wherein the spacing between the adjacent wire grid electrodes are made narrower in the direction of the movement of said photosensitive member relative to said simultaneous-light-image-projection-and-discharge means.
Claim 6
Dependent Claim
130 words
An electrophotographic copying machine comprising a photosensitive member having an insulating surface; a first charger means for imparting a uniform first charge upon the surface of said photosensitive member; simultaneous-light-image-projection-and-discharge means for projecting a light image upon the surface of said photosensitive member and simultaneously effecting an a-c corona discharge onto the surface of said photosensitive member, said simultaneous-light-image-projection-and-discharge means comprising corona discharge electrodes, grounded auxiliary electrodes surrounding said corona discharge electrodes and defining an optical aperture and an opening for discharge, an insulating member disposed over each of said auxiliary electrodes in opposed relation with said corona discharge electrodes, and means for equalizing the surface charges including grounded grid electrodes disposed in the proximity of said discharge opening; and means for illuminating the whole surface of said photosensitive member.
Claim 7
Dependent Claim
130 words
An electrophotographic copying machine comprising a photosensitive member having an insulating surface; a first charger means for imparting a uniform first charge upon the surface of said photosensitive member; simultaneous-light-image-projection-and-discharge means for projecting a light image upon the surface of said photosensitive member and simultaneously effecting an a-c corona discharge onto the surface of said photosensitive member, said simultaneous-light-image-projection-and-discharge means comprising corona discharge electrodes, grounded auxiliary electrodes surrounding said corona discharge electrodes and defining an optical aperture and an opening for discharge, an insulating member disposed over each of said auxiliary electrodes in opposed relation with said corona discharge electrodes, and means for equalizing the surface charges including grounded grid electrodes disposed in the proximity of said discharge opening; and means for illuminating the whole surface of said photosensitive member.
Claim 8
Dependent Claim
21 words
An electrophotographic copying machine as set forth in claim 5 wherein said grounded grid electrodes comprise a plurality of wire electrodes.
Claim 9
Dependent Claim
37 words
An electrophotographic copying machine as set forth in claim 6 wherein the spacing between the adjacent wire grid electrodes are made narrower in the direction of the movement of said photosensitive member relative to said simultaneous-light-image-projection-and-discharge means.
References Cited (Backward Citations)
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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 |