US4949125A
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Method and apparatus for color electrophotography
Assignee: Panasonic Holdings Corp
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Filing: 1988-10-21
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Granted: 1990-08-14
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Expires: 2008-10-21
Abstract
Abstract A charging process, an exposure process, and a development process are performed to form a toner image on a photosensitive member for each of a plurality of different colors. The toner images for the respective colors form a composite color image. The composite color image is transferred to a sheet. A potential of toner on the photosensitive member is varied before the development process for a final color is performed. The colors may be yellow, magenta, and cyan respectively.
Inventors
- 👤 Hajime Yamamoto
- 👤 Kazunori Kitagaki
- 👤 Masahiko Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:14
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/01; G03G15/0142; G03G15/0147; G03G15/0152; G03G15/0157; G03G15/0163
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
81 words
A method of color electrophotography comprising the steps of: (a) performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; (b) transferring the composite color image to a sheet; and (c) varying a potential of toner on the photosensitive member before the development process for a final color is performed.
Claim 2
Independent Claim
81 words
A method of color electrophotography comprising the steps of: (a) performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; (b) transferring the composite color image to a sheet; and (c) varying a potential of toner on the photosensitive member before the development process for a final color is performed.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein the colors are yellow, magenta, and cyan respectively.
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein the potential varying step follows the development process for a first color.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the potential varying step follows the development process for a second color but precedes the charging process for a third color.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein the potential varying step comprises applying ac corona to the photosensitive member.
Claim 7
Dependent Claim
34 words
The method of claim 1 wherein the potential varying step comprises applying dc corona to the photosensitive member, the dc corona having a polarity opposite to a polarity of charge of the photosensitive member.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the photosensitive member comprises amorphous selenium-based material.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the photosensitive member comprises amorphous selenium-arsenic-based material.
Claim 10
Dependent Claim
12 words
The method of claim 1 wherein the photosensitive member comprises organic material.
Claim 11
Independent Claim
86 words
An apparatus for color electrophotography comprising: (a) means for performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; (b) means for transferring the composite color image to a sheet; and (c) means for decreasing a quantity of charges of toner on the photosensitive member before the development process for a final color is performed.
Claim 12
Independent Claim
86 words
An apparatus for color electrophotography comprising: (a) means for performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; (b) means for transferring the composite color image to a sheet; and (c) means for decreasing a quantity of charges of toner on the photosensitive member before the development process for a final color is performed.
Claim 13
Dependent Claim
14 words
The apparatus of claim 10 wherein the colors are yellow, magenta, and cyan respectively.
Claim 14
Dependent Claim
20 words
The apparatus of claim 10 wherein the decrease in the charge quantity follows the development process for a first color.
Claim 15
Dependent Claim
29 words
The apparatus of claim 10 wherein the decrease in the charge quantity follows the development process for a second color but precedes the charging process for a third color.
Claim 16
Dependent Claim
20 words
The apparatus of claim 10 wherein the charge decreasing means comprises means for applying ac corona to the photosensitive member.
Claim 17
Dependent Claim
36 words
The apparatus of claim 10 wherein the charge decreasing means comprises means for applying dc corona to the photosensitive member, the dc corona having a polarity opposite to a polarity of charge of the photosensitive member.
Claim 18
Independent Claim
84 words
An apparatus for color electrophotography comprising: (a) means for performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of yellow, magenta, and cyan, wherein the yellow, magenta, and cyan toner images form a composite color image; (b) means for transferring the composite color image to a sheet; and (c) means for varying a potential of toner on the photosensitive member after the magenta development process but before the cyan charging process.
Claim 19
Independent Claim
84 words
An apparatus for color electrophotography comprising: (a) means for performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of yellow, magenta, and cyan, wherein the yellow, magenta, and cyan toner images form a composite color image; (b) means for transferring the composite color image to a sheet; and (c) means for varying a potential of toner on the photosensitive member after the magenta development process but before the cyan charging process.
Claim 20
Dependent Claim
20 words
The apparatus of claim 16 wherein the potential varying means comprises means for applying ac corona to the photosensitive member.
Claim 21
Dependent Claim
36 words
The apparatus of claim 16 wherein the potential varying means comprises means for applying dc corona to the photosensitive member, the dc corona having a polarity opposite to a polarity of charge of the photosensitive member.
Claim 22
Independent Claim
229 words
An apparatus for color electrophotography comprising: (a) a photosensitive member; (b) means for charging the photosensitive member in a first charging process; (c) means for, after the first charging process, exposing the photosensitive member to light representative of a first color information in a first exposure process and thereby forming a first electrostatic latent image corresponding to the first color information on the photosensitive member; (d) a first color toner; (e) means for developing the first electrostatic latent image into a corresponding first color toner image by use of the first color toner in a first development process; (f) means for, after the first development process, varying a potential of a portion of the photosensitive member which carries the first color toner; (g) means for, after the potential variation, charging the photosensitive member in a second charging process; (h) means for, after the second charging process, exposing the photosensitive member to light representative of a second color information in a second exposure process and thereby forming a second electrostatic latent image corresponding to the second color information on the photosensitive member; (i) a second color toner; and (j) means for developing the second electrostatic latent image into a corresponding second color toner image by use of the second color toner in a second development process, wherein the first and second color toner images form a composite color toner image.
Claim 23
Independent Claim
229 words
An apparatus for color electrophotography comprising: (a) a photosensitive member; (b) means for charging the photosensitive member in a first charging process; (c) means for, after the first charging process, exposing the photosensitive member to light representative of a first color information in a first exposure process and thereby forming a first electrostatic latent image corresponding to the first color information on the photosensitive member; (d) a first color toner; (e) means for developing the first electrostatic latent image into a corresponding first color toner image by use of the first color toner in a first development process; (f) means for, after the first development process, varying a potential of a portion of the photosensitive member which carries the first color toner; (g) means for, after the potential variation, charging the photosensitive member in a second charging process; (h) means for, after the second charging process, exposing the photosensitive member to light representative of a second color information in a second exposure process and thereby forming a second electrostatic latent image corresponding to the second color information on the photosensitive member; (i) a second color toner; and (j) means for developing the second electrostatic latent image into a corresponding second color toner image by use of the second color toner in a second development process, wherein the first and second color toner images form a composite color toner image.
Claim 24
Dependent Claim
29 words
The apparatus of claim 19 wherein the potential varying means comprises means for decreasing the potential of the portion of the photosensitive member which carries the first color toner.
Claim 25
Independent Claim
79 words
A method of color electrophotography comprising the steps of: performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member of each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; transferring the composite color image to a sheet; and lowering a potential of toner on the photosensitive member before the following development process for a final color is performed.
Claim 26
Independent Claim
79 words
A method of color electrophotography comprising the steps of: performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member of each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; transferring the composite color image to a sheet; and lowering a potential of toner on the photosensitive member before the following development process for a final color is performed.
Claim 27
Independent Claim
87 words
A method of color electrophotography comprising the steps of: performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; transferring the composite color image to a sheet; and lowering a potential of a toner portion comprised of superposition with two colors on the photosensitive member before the following development process for a final color is performed.
Claim 28
Independent Claim
87 words
A method of color electrophotography comprising the steps of: performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of a plurality of different colors, wherein the toner images for the respective colors form a composite color image; transferring the composite color image to a sheet; and lowering a potential of a toner portion comprised of superposition with two colors on the photosensitive member before the following development process for a final color is performed.
Claim 29
Independent Claim
86 words
A method of color electrophotography comprising the steps of: performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of the yellow, magenta, and cyan colors, wherein the toner images for the respective colors form a composite color image; transferring the composite color image to a sheet; and lowering a potential of the toner in the magenta color portion of the photosensitive member before the following development process for the cyan color is performed.
Claim 30
Independent Claim
86 words
A method of color electrophotography comprising the steps of: performing a charging process, an exposure process, and a development process to form a toner image on a photosensitive member for each of the yellow, magenta, and cyan colors, wherein the toner images for the respective colors form a composite color image; transferring the composite color image to a sheet; and lowering a potential of the toner in the magenta color portion of the photosensitive member before the following development process for the cyan color is performed.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |