US4600295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image forming apparatus
Assignee: Canon Inc
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Filing: 1984-11-26
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Granted: 1986-07-15
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Expires: 2004-11-26
Abstract
Abstract There is disclosed a copier employing a square wave developing bias voltage instead of the conventional sinusoidal AC developing bias. Such square wave developing bias reduces the moving energy of the toner and prevents the discharge between the developing sleeve and the photosensitive drum.
Inventors
- 👤 Koji Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:38
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/065
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
78 words
An image forming apparatus comprising: image forming means for forming an image on a recording member; wherein said image forming means comprises latent image forming means for forming an electrostatic latent image on said recording member and developing means for recording said electrostatic latent image visible; bias voltage generating means for supplying said developing means with a bias voltage having a square wave form; and setting means for setting, in variable manner, duty ratio of said square wave.
Claim 2
Dependent Claim
78 words
An image forming apparatus comprising: image forming means for forming an image on a recording member; wherein said image forming means comprises latent image forming means for forming an electrostatic latent image on said recording member and developing means for recording said electrostatic latent image visible; bias voltage generating means for supplying said developing means with a bias voltage having a square wave form; and setting means for setting, in variable manner, duty ratio of said square wave.
Claim 3
Dependent Claim
42 words
An image forming apparatus according to claim 1, wherein said bias voltage generating means comprises signal generating means for generating a sawtooth wave, and comparator means for comparing the sawtooth wave generated by said signal generating means with a determined reference voltage.
Claim 4
Dependent Claim
19 words
An image forming apparatus according to claim 2, wherein said setting means is adapted to set said reference voltage.
Claim 5
Dependent Claim
27 words
An image forming apparatus according to claim 3, wherein said setting means comprises regulating means for manually regulating said reference voltage to render said duty ratio variable.
Claim 6
Dependent Claim
36 words
An image forming apparatus according to claim 3, wherein said setting means comprises control means for regulating said reference voltage according to image forming conditions of said image forming means thereby rendering said duty ratio variable.
Claim 7
Dependent Claim
35 words
An image forming apparatus according to claim 1, wherein said setting means is adapted to select different duty ratios respectively in an image forming period and an image non-forming period of said image forming means.
Claim 8
Dependent Claim
32 words
An image forming apparatus according to claim 1, wherein said setting means is adapted to select different duty ratios respectively in the image area and the non-image area of said recording member.
Claim 9
Dependent Claim
40 words
An image forming apparatus according to claim 5, wherein said control means comprises detecting means for detecting the surface state of said recording member and is adapted to regulate said reference voltage according to the output of said detecting means.
Claim 10
Dependent Claim
17 words
An image forming apparatus according to claim 8, wherein said detecting means comprises a surface potential meter.
Claim 11
Dependent Claim
109 words
An image forming apparatus comprising: image forming means for forming an image on a recording member; wherein said image forming means comprises latent image forming means for forming an electrostatic latent image on said recording member and developing means for rendering said electrostatic latent image visible; and bias voltage generating means for supplying said developing means with a bias voltage; wherein said bias voltage generating means comprises first voltage generating means for generating a square wave voltage of a determined duty ratio and second voltage generating means for generating a determined DC voltage, wherein said bias voltage is obtained by superposing said DC voltage on said square wave voltage.
Claim 12
Dependent Claim
109 words
An image forming apparatus comprising: image forming means for forming an image on a recording member; wherein said image forming means comprises latent image forming means for forming an electrostatic latent image on said recording member and developing means for rendering said electrostatic latent image visible; and bias voltage generating means for supplying said developing means with a bias voltage; wherein said bias voltage generating means comprises first voltage generating means for generating a square wave voltage of a determined duty ratio and second voltage generating means for generating a determined DC voltage, wherein said bias voltage is obtained by superposing said DC voltage on said square wave voltage.
Claim 13
Dependent Claim
33 words
An image forming apparatus according to claim 10, wherein said first voltage generating means comprises first setting means for setting said duty ratio by means of which said duty ratio is rendered variable.
Claim 14
Dependent Claim
43 words
An image forming apparatus according to claim 11, wherein said first voltage generating means comprises signal generating means for generating a sawtooth wave and comparator means for comparing the sawtooth wave voltage generated by said signal generating means with a determined reference voltage.
Claim 15
Dependent Claim
20 words
An image forming apparatus according to claim 12, wherein said first setting means is adapted to set said reference voltage.
Claim 16
Dependent Claim
28 words
An image forming apparatus according to claim 13, wherein said first setting means comprises regulating means for manually regulating said reference voltage to render said duty ratio variable.
Claim 17
Dependent Claim
37 words
An image forming apparatus according to claim 13, wherein said first setting means comprises control means for regulating said reference voltage according to image forming conditions of said image forming means thereby rendering said duty ratio variable.
Claim 18
Dependent Claim
39 words
An image forming apparatus according to claim 10, wherein said second voltage generating means comprises second setting means for setting the value of said DC voltage, by means of which said value of said DC voltage is rendered variable.
Claim 19
Dependent Claim
25 words
An image forming apparatus according to claim 16, wherein said second setting means comprises regulating means for manually regulating the value of said DC voltage.
Claim 20
Dependent Claim
34 words
An image forming apparatus according to claim 16, wherein said second setting means comprises control means for regulating the value of said DC voltage according to image forming conditions of said image forming means.
Claim 21
Dependent Claim
43 words
An image forming apparatus according to claim 18, wherein said control means comprises detecting means for detecting the surface state of said recording member and is adapted to regulate the value of said DC voltage according to the output of said detecting means.
Claim 22
Dependent Claim
17 words
An image forming apparatus according to claim 19, wherein said detecting means comprises a surface potential meter.
Claim 23
Dependent Claim
96 words
An image forming apparatus comprising: image forming means for forming an image on a recording member; wherein said image forming means comprises latent image forming means for forming an electrostatic latent image on said recording member and developing means for rendering said electrostatic latent image visible; bias voltage generating means for supplying said developing means with a bias voltage composed of a square wave voltage and a DC voltage superposed thereto; and control means for regulating the duty ratio or the value of said DC voltage according to image forming conditions of said image forming means.
Claim 24
Dependent Claim
96 words
An image forming apparatus comprising: image forming means for forming an image on a recording member; wherein said image forming means comprises latent image forming means for forming an electrostatic latent image on said recording member and developing means for rendering said electrostatic latent image visible; bias voltage generating means for supplying said developing means with a bias voltage composed of a square wave voltage and a DC voltage superposed thereto; and control means for regulating the duty ratio or the value of said DC voltage according to image forming conditions of said image forming means.
Claim 25
Dependent Claim
43 words
An image forming apparatus according to claim 21, wherein said control means comprises detecting means for detecting the surface state of said recording member and is adapted to regulate the value of said DC voltage according to the output of said detecting means.
Claim 26
Dependent Claim
17 words
An image forming apparatus according to claim 22, wherein said detecting means comprises a surface potential meter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-14 | 1990-01-13 | 1990-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-14 | 1994-01-13 | 1994-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-14 | 1998-01-13 | 1998-07-15 | $7700.00 | Window Closed / Lapsed |