| 摘要 |
PROBLEM TO BE SOLVED: To allow reading in high quality by detecting foreign matter such as dust sticking on an optical component in an optical path even in constitution wherein one optical system serves for both illumination light and read light. SOLUTION: A reference plate 43 for flare detection which has its reverse surface painted in black is disposed outside a contact glass 1 where a document is placed, and when flare detecting operation starts, a first scanning body is moved to the position where the reverse surface of the reference plate 43 for flare detection is read, so that a linear imaging element 10 reads its surface image. When neither a deflecting mirror 6 nor return mirrors 8a and 8b have dust thereupon, the read image is entirely black and then it is judged that there is no foreign matter. If foreign matter such as dust is present on the deflecting mirror 6 or the return mirror 8a or 8b, gray or white data is read in the read image by the linear imaging element 10 and its data value is compared with a previously set value to judge that there is the foreign matter when the data is whiter than the threshold value. COPYRIGHT: (C)2008,JPO&INPIT
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