Patent EP0263501A1 successfully refreshed from Google Patents.
EP0263501A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
electrophotographic recording apparatus for forming a multicolor image
Assignee: NEC Corp
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Filing: 1987-10-07
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Granted: —
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Expires: 2007-10-07
Abstract
Abstract The present invention relates to an electrophotographic recording apparatus which forms a multicolor image on a surface of a photoconductive drum (1) and then transfers the multicolor image to recording paper (9). The electrophotographic recording apparatus is provided, in addition to a conventional charger unit (2) and a first developing unit (4) with a second charger unit (5) for charging a surface of the photoconductive drum (1) after the first visible image is formed thereon so as to increase the surface potential of the photoconductive drum (1) to prevent the first visible image from being mixed with a second color and scratched off from the surface of the photoconductive drum (1) by a second developing unit (7).
Inventors
- 👤 Hideaki Abe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 22:00
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/01; G03G15/0142; G03G15/0147; G03G15/0152; G03G15/0157; G03G15/0163
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
191 words
An electrophotographic recording apparatus comprising a rotary photoconductive drum, a first charger unit for uniformly charging a surface of said photoconductive drum to increase a surface potential of said photoconductive drum, a first exposure unit for selectively exposing said surface of said phtotoconductive drum so as to decrease the surface potential in the first exposed area to form a first electrostatic latent image, a first developing unit for developing said first electrostatic latent image with a first color toner to form a first visible image, a second charger unit for recharging said surface of said photoconductive drum on which said first visible image is formed to increase the surface potential in said first exposed area to a first value, a second exposure unit for selectively exposing said surface of said phtotoconductive drum so as to decrease the surface potential in the second exposed area to form a second electrostatic latent image, the surface potential in said second exposed area being a second value less than said first value, and a second developing unit for developing said second electrostatic latent image with a second color toner to form a second visible image.
Claim 2
Dependent Claim
191 words
An electrophotographic recording apparatus comprising a rotary photoconductive drum, a first charger unit for uniformly charging a surface of said photoconductive drum to increase a surface potential of said photoconductive drum, a first exposure unit for selectively exposing said surface of said phtotoconductive drum so as to decrease the surface potential in the first exposed area to form a first electrostatic latent image, a first developing unit for developing said first electrostatic latent image with a first color toner to form a first visible image, a second charger unit for recharging said surface of said photoconductive drum on which said first visible image is formed to increase the surface potential in said first exposed area to a first value, a second exposure unit for selectively exposing said surface of said phtotoconductive drum so as to decrease the surface potential in the second exposed area to form a second electrostatic latent image, the surface potential in said second exposed area being a second value less than said first value, and a second developing unit for developing said second electrostatic latent image with a second color toner to form a second visible image.
Claim 3
Dependent Claim
66 words
The electophotographic recording apparatus as claimed in Claim 1, wherein said second developing unit is applied with a bias voltage V B2 for adhereing said second color toner to said second exposed area, said first potential in said first exposed area being in a range from 0.4 V B2 to 0.8 V B2 when said second electrostatic latent image is developed by said second developing unit.
Claim 4
Dependent Claim
29 words
The electrophotographic recording apparatus as claimed in Claim 1 or 2, wherein the electric charge of said first color toner is larger than that of said second color toner.
Claim 5
Dependent Claim
24 words
The electrophotographic recording apparatus as claimed in Claims 1 to 3, wherein said photoconductive drum has a photoconductive layer consisting of an amorphous silicon.
References Cited (Backward Citations)
DE2938331C2
Cited
EP0090595A1
Cited
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