| 摘要 |
PURPOSE:To detect original size easily and securely at low cost by providing a means which compares the 2nd data of photosensors with stored data and signifying detection data when data sent from the respective photosensors are coincident. CONSTITUTION:A detecting device 15 consists of two photosensors 15a and 15b such as photodiodes; and the photosensor 15 is used to decide the quantity of movement from a reference position Po and the photosensor 15b is used to decide the width of an original. The sensor outputs of the photosensors 15a and 15b are turned on when the quantities of reflected light p-hotodetected by the photosensors 15a and 15b are larger than the predetermined reference quantity of light and turned off when not. Consequently, the size of the original 1 which is set is decided from the combination of the quantity l of movement of a scanner 7 (detecting device 15) calculated by converting the output variation of the photosensor 15a and the current output state of the photosensor 15b.
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