EP0319309A2
Expired / Lapsed
EP
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An apparatus for reading an image
Assignee: Sharp Corp
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Filing: 1988-12-01
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Granted: —
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Expires: 2008-12-01
Abstract
Abstract An apparatus for reading an image from a document which comprises a light emitting means having a plurality of LEDs (24), a back plate (23) disposed in the vicinity of a region in which the document (21) is to be irradiated, an optical sensor (25), an adjust means (32) which changes the output level of each LEDs, and a control means (31) which controls the adjust means in such a manner that the output level of each of the LEDs is equal to each other, in response to the output signals of the optical sensor which are obtained from light beams reflected from the back plate when no document is in the region. In the apparatus, the document can be irradiated uniformly by the LEDs.
Inventors
- 👤 Toshiaki Karita
- 👤 Takashi Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 17:33
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40056; H04N1/401
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
156 words
An apparatus for reading an image from a document comprising: a light emitting means which has a plurality of light emitting devices; a back plate disposed in the vicinity of a region in which the document is to be irradiated; an optical sensor means which produces signals the level of each of which corresponds to the level of light beams which have been reflected from said document or back plate and are incident on said light sensor means; an adjust means which changes the output level of each of or each group of said light emitting devices; and a control means which controls said adjust means in such a manner that the output level of each of said light emitting devices is substantially equal to each other, in response to said output signals of said optical sensor means which are obtained from light beams reflected from said back plate when no document is in said region.
Claim 2
Independent Claim
156 words
An apparatus for reading an image from a document comprising: a light emitting means which has a plurality of light emitting devices; a back plate disposed in the vicinity of a region in which the document is to be irradiated; an optical sensor means which produces signals the level of each of which corresponds to the level of light beams which have been reflected from said document or back plate and are incident on said light sensor means; an adjust means which changes the output level of each of or each group of said light emitting devices; and a control means which controls said adjust means in such a manner that the output level of each of said light emitting devices is substantially equal to each other, in response to said output signals of said optical sensor means which are obtained from light beams reflected from said back plate when no document is in said region.
Claim 3
Dependent Claim
40 words
An apparatus according to claim 1, wherein said control means comprises an A/D converter which converts said signals of said optical sensor means into digital signals, and said control means controls said adjust means in response to said digital signals.
Claim 4
Dependent Claim
25 words
An apparatus according to claim 1, wherein said A/D converter produces two-value signals from said signals of said optical sensor means, for reading an image.
Claim 5
Dependent Claim
18 words
An apparatus according to claim 1, wherein each of said light emitting devices has a light emitting diode.
Claim 6
Dependent Claim
29 words
An apparatus according to claim 4, wherein said adjust means are variable resistors which are respectively connected to said light emitting diode of each of said light emitting devices.
Claim 7
Dependent Claim
20 words
An apparatus according to claim 1, wherein each of said light emitting devices has a group of light emitting diodes.
Claim 8
Dependent Claim
31 words
An apparatus according to claim 6, wherein said adjust means are variable resistors which are respectively connected to said group of light emitting diodes of each of said light emitting devices.
References Cited (Backward Citations)
No citation records indexed.
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