Patent US722038A successfully refreshed from Google Patents.
Patent US4862286A successfully refreshed from Google Patents.
US4862286A
Expired / Lapsed
US
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Image reading apparatus which adjusts image signals to improve signal balance
Assignee: Canon Inc
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Filing: 1987-11-12
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Granted: 1989-08-29
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Expires: 2007-11-12
Abstract
Abstract An image reading apparatus includes a plurality of linear sensors for reading an image of a document. Each linear sensor reads a different portion of a line of the document in a divided manner. A plurality of clamp circuits control black levels of signals generated by the plurality of linear sensors to be a black reference level. A plurality of multipliers control white levels of signals generated by the plurality of linear sensor means which are level-controlled by the clamp circuits so as to be a white reference level.
Inventors
- 👤 Kenichi Suda
- 👤 Shizuo Hasegawa
- 👤 Nobuo Matsuoka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:00
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40056; H04N25/00; H04N25/60; H04N25/63; H04N25/633
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
113 words
An image reading apparatus comprising: a plurality of linear sensor means for reading an image of a document, each of said linear sensor means reading a different portion of a line of the document in a divided manner; a plurality of level shift means each for shifting a level of a signal generated by a respective one of said plurality of linear sensor means; and control means for controlling said plurality of level shift means on the basis of a plurality of black reference signals generated by said plurality of linear sensor means, so as to align levels of those black reference signals that correspond to a boundary of adjacent linear sensor means.
Claim 2
Dependent Claim
113 words
An image reading apparatus comprising: a plurality of linear sensor means for reading an image of a document, each of said linear sensor means reading a different portion of a line of the document in a divided manner; a plurality of level shift means each for shifting a level of a signal generated by a respective one of said plurality of linear sensor means; and control means for controlling said plurality of level shift means on the basis of a plurality of black reference signals generated by said plurality of linear sensor means, so as to align levels of those black reference signals that correspond to a boundary of adjacent linear sensor means.
Claim 3
Dependent Claim
26 words
An apparatus according to claim 1, wherein said plurality of linear sensor means generate said plurality of black reference signals by reading a black reference member.
Claim 4
Dependent Claim
23 words
An apparatus according to claim 1, further comprising converting means for converting signals from said plurality of level shift means into digital signals.
Claim 5
Dependent Claim
30 words
An apparatus according to claim 1, wherein each of said plurality of linear sensor means reads a color image of a document and generates a plurality of color component signals.
Claim 6
Dependent Claim
21 words
An apparatus according to claim 1, wherein said control means has storing means for storing the plurality of black reference signals.
Claim 7
Dependent Claim
21 words
An apparatus according to claim 1, further comprising means for linking the signals level-shifted by said plurality of level shift means.
Claim 8
Dependent Claim
120 words
An image reading apparatus comprising: a plurality of linear sensor means for reading an image of a document, each of said linear sensor means reading a different portion of a line of the document in a divided manner; a plurality of black level control means each for controlling a black level of a signal generated by respective ones of said plurality of linear sensor means to align black levels of those signals that correspond to a boundary of adjacent linear sensor means; and a plurality of white control means each for controlling a white level of a signal which is level-controlled by a respective one of said plurality of black level control means, so as to be white reference level.
Claim 9
Dependent Claim
120 words
An image reading apparatus comprising: a plurality of linear sensor means for reading an image of a document, each of said linear sensor means reading a different portion of a line of the document in a divided manner; a plurality of black level control means each for controlling a black level of a signal generated by respective ones of said plurality of linear sensor means to align black levels of those signals that correspond to a boundary of adjacent linear sensor means; and a plurality of white control means each for controlling a white level of a signal which is level-controlled by a respective one of said plurality of black level control means, so as to be white reference level.
Claim 10
Dependent Claim
37 words
An apparatus according to claim 7, wherein said plurality of black level control means perform a control operation on the basis of signals obtained by reading a black reference member using said plurality of linear sensor means.
Claim 11
Dependent Claim
37 words
An apparatus according to claim 7, wherein said plurality of white level control means perform a control operation on the basis of signals obtained by reading a white reference member using said plurality of linear sensor means.
Claim 12
Dependent Claim
30 words
An apparatus according to claim 7, wherein each of said plurality of linear sensor means reads a color image of a document and generates a plurality of color component signals.
Claim 13
Dependent Claim
21 words
An apparatus according to claim 7, further comprising means for linking the signals level-controlled by said plurality of white control means.
References Cited (Backward Citations)
JPS53108228A
Cited
AT377862B
Cited
JPS54107213A
Cited
US4216503A
Cited
DE2915398A1
Cited
DE3014629A1
Cited
US4274111A
Cited
JPS56102168A
Cited
JPS56111374A
Cited
US4285004A
Cited
US4356513A
Cited
US4589034A
Cited
JPS5856570A
Cited
EP0233990A2
Cited
US4525741A
Cited
JPS5986362A
Cited
JPS5986361A
Cited
US4729035A
Cited
US4734787A
Cited
US4691114A
Cited
GB2156628A
Cited
US4644391A
Cited
EP0169411A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-08-28 | 1993-02-27 | 1993-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-28 | 1997-02-27 | 1997-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-28 | 2001-02-27 | 2001-08-29 | $7700.00 | Window Closed / Lapsed |