US4468110A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for electrophotography
Assignee: Canon Inc
•
Filing: 1982-06-22
•
Granted: 1984-08-28
•
Expires: 2002-06-22
Abstract
Abstract An electrophotographic process including forming, on a photosensitive plate, an electrostatic latent image corresponding to optical information, developing the latent image by the reversal development and transferring the developed image onto a transfer material includes the improvement whereby a voltage of polarity opposite to that of the developer is applied to the photosensitive plate at least during the time from the end of the reversal development to the transfer step. This improvement in the electrophotographic process and apparatus for same prevents developer particles from being scattered away from the photosensitive plate and thereby also avoids the trouble of distortion of the image at the transfer step.
Inventors
- 👤 Koichi Tanigawa
- 👤 Masaharu Ohkubo
- 👤 Masayoshi Takahashi
- 👤 Yasuyuki Tamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 04:37
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/06; G03G13/08
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
85 words
In an electrophotographic process including the steps of forming, on a photosensitive medium, an electrostatic latent image corresponding to optical information applied on said photosensitive medium, developing said electrostatic latent image by reversal development using a developer and transferring said developed image onto a transfer material, the improvement residing in that a voltage having a polarity opposite to the polarity of said developer is applied to said photosensitive medium at least during the time from the end of said reversal development to said transfer step.
Claim 2
Dependent Claim
85 words
In an electrophotographic process including the steps of forming, on a photosensitive medium, an electrostatic latent image corresponding to optical information applied on said photosensitive medium, developing said electrostatic latent image by reversal development using a developer and transferring said developed image onto a transfer material, the improvement residing in that a voltage having a polarity opposite to the polarity of said developer is applied to said photosensitive medium at least during the time from the end of said reversal development to said transfer step.
Claim 3
Dependent Claim
111 words
In an electrophotographic process including the step of forming an image corresponding to an optical information applied to a photosensitive medium, the improvement residing in the steps of: forming an electrostatic latent image on the photosensitive medium corresponding to the optical information applied to the photosensitive medium while a voltage of a selected polarity is being applied to an electroconductive substrate; applying a developer to said optical information applied area of said photosensitive medium, said developer having a charge of the opposite polarity to the polarity of said voltage applied to the electroconductive substrate of said photosensitive medium; and transferring said developed image onto a transfer material from said photosensitive medium.
Claim 4
Dependent Claim
111 words
In an electrophotographic process including the step of forming an image corresponding to an optical information applied to a photosensitive medium, the improvement residing in the steps of: forming an electrostatic latent image on the photosensitive medium corresponding to the optical information applied to the photosensitive medium while a voltage of a selected polarity is being applied to an electroconductive substrate; applying a developer to said optical information applied area of said photosensitive medium, said developer having a charge of the opposite polarity to the polarity of said voltage applied to the electroconductive substrate of said photosensitive medium; and transferring said developed image onto a transfer material from said photosensitive medium.
Claim 5
Dependent Claim
99 words
In an electrophotographic apparatus for forming an image on a photosensitive medium according to the optical information applied thereto, the improvement residing in the provision of: a photosensitive medium having an electroconductive substrate; means for forming a latent image on said photosensitive medium according to the optical information applied thereto; developing means for applying a developer charged with a selected polarity onto the area of said photosensitive medium where said optical information has been applied; and means for applying to said electroconductive substrate of the photosensitive medium a voltage of the opposite polarity to the polarity of said developer.
Claim 6
Dependent Claim
99 words
In an electrophotographic apparatus for forming an image on a photosensitive medium according to the optical information applied thereto, the improvement residing in the provision of: a photosensitive medium having an electroconductive substrate; means for forming a latent image on said photosensitive medium according to the optical information applied thereto; developing means for applying a developer charged with a selected polarity onto the area of said photosensitive medium where said optical information has been applied; and means for applying to said electroconductive substrate of the photosensitive medium a voltage of the opposite polarity to the polarity of said developer.
Claim 7
Dependent Claim
108 words
In an electrophotographic apparatus for forming an image on a photosensitive medium according to the optical information applied thereto, the improvement residing in the provision of: a photosensitive medium having an electroconductive substrate and a photoconductive layer provided thereon; means for applying to the surface of said photosensitive medium a selected polarity of charge; means for applying an optical information to the surface of said photosensitive medium; developing means for applying a developer charged with the same polarity as that of said applied charge; and means for applying to the electroconductive substrate of said photosensitive medium a voltage of the opposite polarity to that of said charged developer.
Claim 8
Dependent Claim
108 words
In an electrophotographic apparatus for forming an image on a photosensitive medium according to the optical information applied thereto, the improvement residing in the provision of: a photosensitive medium having an electroconductive substrate and a photoconductive layer provided thereon; means for applying to the surface of said photosensitive medium a selected polarity of charge; means for applying an optical information to the surface of said photosensitive medium; developing means for applying a developer charged with the same polarity as that of said applied charge; and means for applying to the electroconductive substrate of said photosensitive medium a voltage of the opposite polarity to that of said charged developer.
Claim 9
Dependent Claim
17 words
The improvement as set forth in claim 4, wherein said photosensitive medium is supported for endless movement.
Claim 10
Dependent Claim
30 words
The improvement as set forth in claim 4, wherein said optical information applying means comprises an information part from which a beam of light is emitted toward said photosensitive medium.
Claim 11
Dependent Claim
141 words
An electrophotographic apparatus for forming an image on a photosensitive medium according to the optical information applied thereto, said apparatus comprising: a photosensitive medium basically composed of an electroconductive substrate, a photoconductive layer and an insulating layer; means for applying on the surface of said photosensitive medium a primary charge of a selected polarity; means for applying the optical information on said surface; means for applying on said surface a charge containing a component of the opposite polarity to that of said primary charge nearly simultaneously with said application of optical information; means for whole surface exposure; developing means for applying on said surface a developer charged with the same polarity as that of said primary charge; and means for applying to the electroconductive substrate of said photosensitive medium a voltage of the opposite polarity to that of said charged developer.
Claim 12
Dependent Claim
141 words
An electrophotographic apparatus for forming an image on a photosensitive medium according to the optical information applied thereto, said apparatus comprising: a photosensitive medium basically composed of an electroconductive substrate, a photoconductive layer and an insulating layer; means for applying on the surface of said photosensitive medium a primary charge of a selected polarity; means for applying the optical information on said surface; means for applying on said surface a charge containing a component of the opposite polarity to that of said primary charge nearly simultaneously with said application of optical information; means for whole surface exposure; developing means for applying on said surface a developer charged with the same polarity as that of said primary charge; and means for applying to the electroconductive substrate of said photosensitive medium a voltage of the opposite polarity to that of said charged developer.
Claim 13
Dependent Claim
18 words
An electrophotographic apparatus as set forth in claim 7, wherein said photosensitive medium is supported for endless movement.
Claim 14
Dependent Claim
31 words
An electrophotographic apparatus as set forth in claim 7, wherein said optical information applying means comprises an information part from which a beam of light is emitted toward said photosensitive medium.
References Cited (Backward Citations)
US3659936A
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 |