US4482243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image formation apparatus
Assignee: Canon Inc
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Filing: 1982-08-30
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Granted: 1984-11-13
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Expires: 2002-08-30
Abstract
Abstract An image formation apparatus reproduces both an image of a text and a continuous tone image such as a photograph with excellent gradation. The AC bias voltage to be applied to a developing roller is controlled stepwise or continuously in accordance with the spatial frequency of an original.
Inventors
- 👤 Koji Suzuki
- 👤 Kouki Kuroda
- 👤 Jyoji Nagahira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:57
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/065
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
136 words
An image formation apparatus comprising: a plurality of processing means for forming an image of an original on a recording body, said plurality of processing means having reciprocating means for exposing the original to light, developing means for developing an electrostatic latent image formed on said recording body, and means for applying a bias voltage including an AC component to said developing means; detecting means for detecting a condition of the original in a first scanning by said reciprocating means prior to exposure of the original to light for image formation in a second scanning by said reciprocating means; and control means for controlling the bias voltage applying means to change the AC component of the developing bias voltage in the second scanning in accordance with an output from said detecting means in the first scanning.
Claim 2
Dependent Claim
136 words
An image formation apparatus comprising: a plurality of processing means for forming an image of an original on a recording body, said plurality of processing means having reciprocating means for exposing the original to light, developing means for developing an electrostatic latent image formed on said recording body, and means for applying a bias voltage including an AC component to said developing means; detecting means for detecting a condition of the original in a first scanning by said reciprocating means prior to exposure of the original to light for image formation in a second scanning by said reciprocating means; and control means for controlling the bias voltage applying means to change the AC component of the developing bias voltage in the second scanning in accordance with an output from said detecting means in the first scanning.
Claim 3
Dependent Claim
14 words
An apparatus according to claim 1, wherein the detected condition is a spatial frequency.
Claim 4
Dependent Claim
18 words
An apparatus according to claim 2, wherein said control means controls an oscillation frequency of the AC component.
Claim 5
Dependent Claim
34 words
An apparatus according to claim 3, wherein said control means increases the oscillation frequency of the AC component of the developing bias voltage when the spatial frequency detected by said detecting means is high.
Claim 6
Dependent Claim
34 words
An apparatus according to claim 3, wherein said control means decreases the oscillation frequency of the AC component of the developing bias voltage when the spatial frequency detected by said detecting means is low.
Claim 7
Dependent Claim
28 words
An apparatus according to claim 3, 4 or 5, wherein said control means continuously changes the oscillation frequency of the AC component in accordance with the spatial frequency.
Claim 8
Dependent Claim
28 words
An apparatus according to claim 3, 4 or 5, wherein said control means changes stepwise the oscillation frequency of the AC component in accordance with the spatial frequency.
Claim 9
Dependent Claim
50 words
An apparatus according to claim 3, wherein said detecting means detects the spatial frequency of the original during a forward movement of said reciprocating means, and said control means controls the oscillation frequency of the AC component of the developing bias voltage during a return movement of said reciprocating means.
Claim 10
Dependent Claim
29 words
An apparatus according to claim 1, wherein said plurality of processing means have a half mirror which guides part of reflected light from the original toward said detecting means.
Claim 11
Dependent Claim
16 words
An apparatus according to claim 1 or 9, wherein said detecting means comprises an image sensor.
Claim 12
Dependent Claim
15 words
An apparatus according to claim 1, wherein said developing means further includes a one-component developer.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-13 | 1988-05-14 | 1988-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-13 | 1992-05-14 | 1992-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-13 | 1996-05-14 | 1996-11-13 | $7700.00 | Window Closed / Lapsed |