US4714945A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light exposure controller
Assignee: Sharp Corp
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Filing: 1985-12-18
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Granted: 1987-12-22
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Expires: 2005-12-18
Abstract
Abstract A light exposure controller is provided for detecting a light amount reflected by an original document in a copying machine and controlling the light volume of a copy lamp illuminating the original document according to the detected light amount. The light exposure controller has an auto/manual control mode selector switch. When the automatic control mode is switched over to the manual mode, the light volume is set at a mean value of the light volume for the last automatic control mode copying operation.
Inventors
- 👤 Katsuyoshi Fujiwara
- 👤 Shunju Anzai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:20
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/04; G03G15/043
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
97 words
A light exposure controller, comprising: a lamp for illuminating an original document on a copy document table; means for detecting a quantity of light reflected by said original document; means for controlling a light volume of said lamp according to the detected quantity of light; and mode selector means for selecting either of an automatic or manual exposure control for said lamp, wherein the light volume is set at a mean value of the light volume for the most recent automatic control mode copying operation when the automatic control mode is switched over to the manual mode.
Claim 2
Dependent Claim
97 words
A light exposure controller, comprising: a lamp for illuminating an original document on a copy document table; means for detecting a quantity of light reflected by said original document; means for controlling a light volume of said lamp according to the detected quantity of light; and mode selector means for selecting either of an automatic or manual exposure control for said lamp, wherein the light volume is set at a mean value of the light volume for the most recent automatic control mode copying operation when the automatic control mode is switched over to the manual mode.
Claim 3
Dependent Claim
27 words
The light exposure controller according to claim 1, wherein said means for detecting the quantity of light reflected by the original document is a silicon blue cell.
Claim 4
Dependent Claim
52 words
The light exposure controller according to claim 1, further including a sample hold circuit for holding signals outputted from the means for detecting and means for obtaining a mean value of said holding signals representative of the mean value of the light volume for the most recent automatic control mode copying operation.
Claim 5
Dependent Claim
30 words
The light exposure controller according to claim 3, further including means for outputting control signals to the sample hold circuit and controlling the accurate detection of the reflected light amount.
References Cited (Backward Citations)
US4640603A
Cited
US4542985A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-12-21 | 1991-06-22 | 1991-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-21 | 1995-06-22 | 1995-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-21 | 1999-06-22 | 1999-12-22 | $7700.00 | Window Closed / Lapsed |