EP0622703A2
Expired / Lapsed
EP
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Charging unit
Assignee: Konica Minolta Inc
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Filing: 1994-04-20
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Granted: —
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Expires: 2014-04-20
Abstract
Abstract An image forming apparatus uses a contact-type charger (20) to charge a photoreceptor (10). The D.C. current supplied to the charger is measured while the output value of the A.C. voltage is changed within a predetermined range, and the output value of the A.C. voltage is set in accordance with the measurement result. In an alternative embodiment, the voltage of the photoreceptor is measured by a voltmeter and this value is used for setting the AC. voltage.
Inventors
- 👤 Satoshi C/O Konica Corporation Haneda
- 👤 Kunio C/O Konica Corporation Shigeta
- 👤 Sachie C/O Konica Corporation Hosogoezawa
- 👤 Hiroyuki C/O Konica Corporation Nomori
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 11:42
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0241; G03G15/0266; G03G2215/00; G03G2215/02; G03G2215/021; G03G2215/022
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
159 words
An image forming apparatus, comprising: an image forming member on which an electrostatic latent image is formed; a charging member adapted to come in contact with the image forming member, whereby the image forming member is charged to a charged voltage; an electric source to apply an A.C. voltage and a D.C. voltage onto the charging member; first voltage changing means for changing the output value of the A.C. voltage of the electric source; measuring means for measuring a D.C. current supplied to the charging means; threshold value detection means for detecting a threshold value of the D.C. current from the measuring results of the D.C. current which are measured by the measuring means while the output value of the A.C. voltage is changed within a predetermined range by the first voltage changing means; and setting means for setting the output value of the A.C. voltage in accordance with the threshold value detected by the threshold value detection means.
Claim 2
Dependent Claim
27 words
The image forming apparatus of claim 1, wherein the charging means comprises a sleeve and a magnetic brush which is formed by magnetic particles on the sleeve.
Claim 3
Dependent Claim
15 words
The image forming apparatus of claim 1, wherein the charging means is a charging roller.
Claim 4
Dependent Claim
48 words
The image forming apparatus of claim 1, wherein the setting means sets the threshold value (V P-P )th and the output value of the A.C. voltage so as to satisfy the following relation: 0.8 x (V P-P )th ≦ (V P-P ) ≦ 1.5 x (V P-P )th
Claim 5
Dependent Claim
15 words
The image forming apparatus of claim 1, wherein the D.C. voltage is a constant voltage.
Claim 6
Dependent Claim
23 words
The image forming appratus of claim 1, further comprising second voltage changing means for changing the charged voltage on the image forming member.
Claim 7
Dependent Claim
159 words
An image forming apparatus, comprising: an image forming member on which an electrostatic latent image is formed; a charging member adapted to come in contact with the image forming member, whereby the image forming member is charged to a charged voltage; an electric source to apply an A.C. voltage and a D.C. voltage onto the charging member; first voltage changing means for changing the output value of the A.C. voltage of the electric source; measuring means for measuring the charged voltage on the image forming member; threshold value detection means for detecting a threshold value of the charged voltage from the measuring results of the charged voltage which are measured by the measuring means while the output value of the A.C. voltage is changed within a predetermined range by the first voltage changing means; and setting means for setting the output value of the A.C. voltage in accordance with the threshold value detected by the threshold value detection means.
Claim 8
Dependent Claim
27 words
The image forming apparatus of claim 7, wherein the charging means comprises a sleeve and a magnetic brush which is formed by magnetic particles on the sleeve.
Claim 9
Dependent Claim
15 words
The image forming apparatus of claim 7, wherein the charging means is a charging roller.
Claim 10
Dependent Claim
48 words
The image forming apparatus of claim 7, wherein the setting means sets the threshold value (V P-P )th and the output value of the A.C. voltage so as to satisfy the following relation: 0.8 x (V P-P )th ≦ (V P-P ) ≦ 1.5 x (V P-P )th
Claim 11
Dependent Claim
15 words
The image forming apparatus of claim 7, wherein the D.C. voltage is a constant voltage.
Claim 12
Dependent Claim
23 words
The image forming appratus of claim 7, further comprising second voltage changing means for changing the charged voltage on the image forming member.
References Cited (Backward Citations)
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