Patent US4970557A successfully refreshed from Google Patents.
US4970557A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic apparatus controlling image quality according to condition of deterioration
Assignee: Sharp Corp
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Filing: 1988-08-29
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Granted: 1990-11-13
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Expires: 2008-08-29
Abstract
Abstract Electrophotographic apparatus according to this invention are controlled in different ways such that quality of produced images is not affected by deterioration of the developing agent or the condition of the photoreceptor. A timer may be provided to detect the duration of a rest period to adjust the speed of development accordingly as well as by the number of copies produced. Similar control may be effected by measuring the surface voltage of the photoreceptor by a voltage detector and by adjusting the output level of the principal charger used for uniformly charging the photoreceptor prior to a development process.
Inventors
- 👤 Jitsuo Masuda
- 👤 Hideaki Hagihara
- 👤 Hiroshi Kinashi
- 👤 Junji Morimoto
- 👤 Ken Yamagishi
- 👤 Teruhiko Noguchi
- 👤 Itaru Kawabata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:47
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/50; G03G15/5033; G03G15/5037; G03G15/02; G03G15/0266; G03G15/06; G03G15/08; G03G15/0822; G03G2215/00; G03G2215/00025; G03G2215/00071; G03G2215/00075
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
90 words
An electrophotographic apparatus comprising a photoreceptor having an image forming surface, a timer for detecting duration of rest period of said photoreceptor, and control means for step-wise reducing speed of development on said photoreceptor as the rest period of said photoreceptor detected by said timer becomes longer and step-wise increasing speed of development on said photoreceptor as number of copies processed on said photoreceptor increases, the speed of development being defined as relative speed of said image forming surface with respect to toner which brushes thereagainst in a developing device.
Claim 2
Dependent Claim
90 words
An electrophotographic apparatus comprising a photoreceptor having an image forming surface, a timer for detecting duration of rest period of said photoreceptor, and control means for step-wise reducing speed of development on said photoreceptor as the rest period of said photoreceptor detected by said timer becomes longer and step-wise increasing speed of development on said photoreceptor as number of copies processed on said photoreceptor increases, the speed of development being defined as relative speed of said image forming surface with respect to toner which brushes thereagainst in a developing device.
Claim 3
Dependent Claim
41 words
The apparatus of claim 1 wherein said speed of development is step-wise reduced and increased by said control means according to empirically determined relationship between image density and the number of processed copies and between image density and speed of development.
Claim 4
Dependent Claim
78 words
An electrophotographic apparatus comprising a photoreceptor having an image forming surface, a voltage detector for detecting surface voltage of said photoreceptor, and control means for controlling speed of development of said photoreceptor depending on the surface voltage of said photoreceptor detected by said voltage detector, said speed of development being defined as relative speed of said image forming surface with respect to toner which brushes thereagainst in a developing device and reduced as said detected surface voltage increases.
Claim 5
Dependent Claim
78 words
An electrophotographic apparatus comprising a photoreceptor having an image forming surface, a voltage detector for detecting surface voltage of said photoreceptor, and control means for controlling speed of development of said photoreceptor depending on the surface voltage of said photoreceptor detected by said voltage detector, said speed of development being defined as relative speed of said image forming surface with respect to toner which brushes thereagainst in a developing device and reduced as said detected surface voltage increases.
Claim 6
Dependent Claim
30 words
The apparatus of claim 3 wherein said speed of development is changed by said control means according to empirically determined relationship between image density and surface voltage of said photoreceptor.
Claim 7
Dependent Claim
70 words
An electrophotographic apparatus using two-component developing agent to form a magnetic brush for development process, said apparatus comprising a stirrer roller in a developing tank for stirring developing agent, and control means for causing said stirrer roller to rotate at a faster rate during a predetermined time period after power is switched on and before development is started, said faster rate being faster than a normal rate therefor during development.
Claim 8
Dependent Claim
70 words
An electrophotographic apparatus using two-component developing agent to form a magnetic brush for development process, said apparatus comprising a stirrer roller in a developing tank for stirring developing agent, and control means for causing said stirrer roller to rotate at a faster rate during a predetermined time period after power is switched on and before development is started, said faster rate being faster than a normal rate therefor during development.
Claim 9
Dependent Claim
17 words
The apparatus of claim 5 wherein said predetermined time period starts immediately when power is switched on.
Claim 10
Dependent Claim
19 words
The apparatus of claim 5 wherein said predetermined time period starts when copying operation of said apparatus is started.
Claim 11
Dependent Claim
97 words
An electrophotographic apparatus using two-component developing agent with ferrite carrier to form a magnetic brush for development process, said apparatus comprising a photoreceptor having an image forming surface, a counter for outputting cumulative copy count by said apparatus, a principal charger for charging said photoreceptor, and control means for reducing speed of development of said photoreceptor and/or output level of said principal charger as said copy count outputted by said counter increases, said speed of development being defined as relative speed of said image forming surface with respect to toner which brushes thereagainst in a developing device.
Claim 12
Dependent Claim
97 words
An electrophotographic apparatus using two-component developing agent with ferrite carrier to form a magnetic brush for development process, said apparatus comprising a photoreceptor having an image forming surface, a counter for outputting cumulative copy count by said apparatus, a principal charger for charging said photoreceptor, and control means for reducing speed of development of said photoreceptor and/or output level of said principal charger as said copy count outputted by said counter increases, said speed of development being defined as relative speed of said image forming surface with respect to toner which brushes thereagainst in a developing device.
Claim 13
Dependent Claim
26 words
The apparatus of claim 8 wherein speed of development on said photoreceptor and/or output level of said principal charger is reduced step-wise by said control means.
Claim 14
Dependent Claim
43 words
The apparatus of claim 8 wherein speed of development on said photoreceptor and/or output level of said principal charger is reduced according to empirically determined relationship between image density and copy count and/or between image density and output level of said principal charger.
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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) | 1993-11-12 | 1994-05-14 | 1994-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-11-12 | 1998-05-14 | 1998-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-11-12 | 2002-05-14 | 2002-11-13 | $7700.00 | Window Closed / Lapsed |