EP0476981A2
Expired / Lapsed
EP
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Method and apparatus for forming electrophotographic image
Assignee: Katsuragawa Electric Co Ltd
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Filing: 1991-09-17
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Granted: —
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Expires: 2011-09-17
Abstract
Abstract A method and an apparatus for forming an electrophotographic image based on applying an AC voltage or a voltage obtained by superposing a DC voltage on an AC voltage to an electroconductive base (11) of a sensitive medium (1) having a photoconductive layer (12) formed on the electroconductive base (11), bringing a grounded electroconductive or semi-electroconductive member (1) into contact with or close to the surface of the sensitive medium (1) to charge this surface to a predetermined polarity, and exposing the surface of the sensitive medium (1) to an image to form an electrostatic image.
Inventors
- 👤 Nobutaka Noda
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 01:48
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0216; G03G13/00; G03G13/22; G03G15/06; G03G15/065; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/102
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
An image forming method comprising the steps of: applying an alternating current voltage or a voltage obtained by superposing a direct current voltage on an alternating current voltage,to an electroconductive base of a sensitive medium having a photoconductive layer formed on the electroconductive base; bringing a grounded electroconductive or semi-electroconductive member into contact with or close to a surface of the sensitive medium to charge the same to a predetermined polarity; and exposing the surface of the sensitive medium to an image to form an electrostatic image.
Claim 2
Dependent Claim
63 words
An image forming method according to claim 1, wherein an electroconductive or semi-electroconductive transfer member is disposed in contact with or close to the surface of the sensitive medium and is grounded directly or through induced bias means so that a voltage having a polarity opposite to that of a toner image is induced on the transfer member to transfer the toner image.
Claim 3
Dependent Claim
21 words
An image forming method according to claim 2, wherein a surface of the transfer member is covered with a dielectric layer.
Claim 4
Dependent Claim
62 words
An image forming method according to claim 1, wherein transfer is effected by applying, to the transfer member disposed in contact with or close to the sensitive medium, an alternating current voltage or a voltage obtained by superposing a direct current voltage on an alternating current voltage generally in phase with the bias voltage applied to the base of the sensitive medium.
Claim 5
Dependent Claim
48 words
An image forming method according to claim 4, wherein an intermediate tap is provided in an output winding of a power supply unit for applying the bias voltage to the electroconductive base of the sensitive medium, an output from the intermediate tap being applied to the transfer member.
Claim 6
Dependent Claim
38 words
An image forming method according to claim 15, wherein the output from the power supply unit for applying the bias voltage to the electroconductive base of the sensitive medium is applied to the transfer member through a diode.
Claim 7
Dependent Claim
64 words
An image forming method comprising the steps of: applying a direct current voltage to an electroductive base of a sensitive medium; bringing a grounded electroconductive or semi-electroconductive member into contact with or close to a surface of the sensitive medium to charge the same to a predetermined polarity; and exposing the surface of the sensitive medium to an image to form an electrostatic image.
Claim 8
Dependent Claim
50 words
An image forming method according to claim 7, wherein a positive direct current is applied to the electroconductive base if the sensitive medium is formed of an N-type semiconductor, and a negative direct current is applied to the electroconductive base if the sensitive medium is formed of a P-type semiconductor.
Claim 9
Dependent Claim
44 words
An image forming method according to claim 1, 7 or 8, wherein the electrostatic image is developed by bringing a toner into contact with or close to the surface of the sensitive medium with a developer supplier grounded directly or through induced bias means.
Claim 10
Dependent Claim
26 words
An image forming method according to claim 1 or 9, wherein the electroconductive or semi-electroconductive member is grounded through a rectifier means or induced bias means.
Claim 11
Dependent Claim
25 words
An image forming method according to claim 1 or 9, wherein the electroconductive or semi-electronconductive member has a dielectric layer formed on its outer surface.
Claim 12
Dependent Claim
101 words
An image forming apparatus comprising: a sensitive drum having at least an electroconductive base and a photoconductive layer; means for applying an alternating current voltage or a voltage obtained by superposing a direct current voltage on an alternating current voltage to the electroconductive base of said sensitive drum; an electroconductive or semi-electronconductive member disposed into contact with or close to a surface of said sensitive drum and grounded; means for exposing the surface of said sensitive drum to an image; and a developer supplier disposed closed to the surface of said sensitive drum and grounded directly or through induced bias means.
Claim 13
Dependent Claim
15 words
An image forming apparatus according to claim 12, wherein said member comprises a rotating roller.
Claim 14
Dependent Claim
20 words
An image forming apparatus according to claim 12, further comprising a transfer member grounded directly or through induced bias means.
Claim 15
Dependent Claim
20 words
An image forming apparatus according to claim 12, wherein said member is grounded through rectifier means or induced bias means.
Claim 16
Dependent Claim
23 words
An image forming apparatus according to claim 12 or 15, further comprising an electroconductive cleaning member grounded directly or through induced bias means.
Claim 17
Dependent Claim
26 words
An image forming apparatus according to any one of claims 12-16, wherein said induced bias means includes a diode, constant-voltage diode, varistor or a high-resistance resistor.
References Cited (Backward Citations)
No citation records indexed.
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