| 摘要 |
PURPOSE:To make the focal length adjustment of an original reader easier, by providing test patterns outside an ordinary original placing area on an original platen and performing the focal length adjustment in accordance with the output of a photoelectric converter which reads the test patterns. CONSTITUTION:On an original platen, namely, platen glass 16, test patterns 36a and 36b are provided outside an ordinary original placing area, for example, at the home position HP and return position RP of a photoelectric converter 34 in such a way that the converter 34 can read the test patterns 36a and 36b. The test patterns 36a and 36b are read by the photoelectric converter 34 and the focal length of this original reader is adjusted by adjusting the screw 26 of a fixing section 20 in accordance with the output of the converter 34. Therefore, such complicatedness that picture output is required at every time when focal length adjustment is made can be eliminated and, since output of picture is no longer required as mentioned above, wasteful consumption of paper and toner for focal length adjustment becomes unnecessary.
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