| 摘要 |
PURPOSE:To always secure the accurate and extremely easy self-diagnosis for the state of an OCR by providing a circuit which reads the position of a reference mark put on an original reading surface and checks the read value of the mark position and the relative value among those read values with the standard value. CONSTITUTION:The reference marks 1 and 2 are equal to short lines crossing rectangularly a main scan line (x) at a check position A and set at the places near both ends of the line (x). A reference mark 3 is set at a check point B and is in contact with a secondary scan line (y) like a case where the mark 1 is set at a check point A and is in contact with the line (y). A home position H shows a start waiting point of the normal scan of a reading unit 20. A check circuit 13 reads the reference mark position in the form of the number of clock pulses obtained until a time point where the mark is read. Then the read value of the mark position is compared with the number of clocks that are delivered as long as an OCR is controlled correctly, i.e., the standard value. Thus the state of the OCR can be diagnosed from the difference between the measured value and the standard value.
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