Patent US4779121A successfully refreshed from Google Patents.
US4779121A
Expired / Lapsed
US
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Document scanning device
Assignee: Sharp Corp
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Filing: 1986-10-29
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Granted: 1988-10-18
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Expires: 2006-10-29
Abstract
Abstract A document scanning device such as a copier has defined within itself a point at which the brightness of an original document is detected and a separate point at which the document is scanned. The level of light exposure given to the document is controlled according to the detected brightness. The distance between the aforementioned two points is set with the delay time of an exposure control circuit taken into account. The delay time is set according to the fastest scanning speed of the device and is increased by means of a delay circuit if the scanning speed is deceased.
Inventors
- 👤 Masafumi Okumura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 08:16
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/50; G03G15/5025; G03B; G03B27/00; G03B27/72; G03G15/04; G03G15/043
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
111 words
In a document scanning device having a document brightness detecting point defined at a distance away from a document scanning point, said device being programmed to control light exposure on on original document according to the brightness of said document measured at said document brightness detecting point, said distance being set according to a delay time of an exposure control circuit, the improvement wherien said distance is set according to a delay time of said exposure control circuit corresponding to the fastest speed of scan by said device and wherein said device comprises a delay means for increasing said delay time when the speed of scan by said device is decreased.
Claim 2
Dependent Claim
111 words
In a document scanning device having a document brightness detecting point defined at a distance away from a document scanning point, said device being programmed to control light exposure on on original document according to the brightness of said document measured at said document brightness detecting point, said distance being set according to a delay time of an exposure control circuit, the improvement wherien said distance is set according to a delay time of said exposure control circuit corresponding to the fastest speed of scan by said device and wherein said device comprises a delay means for increasing said delay time when the speed of scan by said device is decreased.
Claim 3
Dependent Claim
23 words
The document scanning device of claim 1 further comprising a central processing unit which serves to control the scanning speed of said device.
Claim 4
Dependent Claim
23 words
The document scanning device of claim 2 wherein said central processing unit controls the scanning speed of said device according to selected magnification.
Claim 5
Dependent Claim
16 words
The document scanning device of claim 1 wherein said delay means comprises a bucket brigade device,
Claim 6
Dependent Claim
42 words
The document scaning device of claim 1 further comprising a clock generator adapted to transmit a plurality of different oscillation frequency signals to said delay means, said delay means determining said delay time according to received one of said oscillation frequency signals.
Claim 7
Dependent Claim
22 words
the document scanning device of claim 5 further comprising a central processing unit which transmits a control signal to said clock generator.
Claim 8
Dependent Claim
29 words
the document scanning device of claim 1 wherein said delay means is programmed either to effect a delay by a predetermined delay time or not to effect any delay.
Claim 9
Dependent Claim
47 words
The document scanning device of claim 7 wherein said delay means effects said delay by said predetermined delay time if said document scanning device is operated in an enlargement mode but does not effect any delay if said document scanning device is operated in a reduction mode.
References Cited (Backward Citations)
US4636063A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-10-18 | 1992-04-18 | 1992-10-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-10-18 | 1996-04-18 | 1996-10-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-10-18 | 2000-04-18 | 2000-10-18 | $7700.00 | Window Closed / Lapsed |