| 摘要 |
PURPOSE: To detect accurate register shift quantity from the extremely small register mark printed on printing paper by processing the output signal of a photodetector array consisting of a large number of photodetectors arranged unidimensionally in the direction right-angled to the running direction of printed matter and the output signals of the respective photodetectors in parallel. CONSTITUTION: The terminals of photodiodes 21a, 21b are connected to the reversal inputs of OP amplifiers 23a, 23b and the output terminals 25a, 25b thereof are connected to an operator to operate vertical and horizontal register shift quantities. In the photodiodes 21a, 21b having the detection positions of horizontal sides being the sides in the direction parallel to the running direction of printed matter of first and second register marks as detection regions, when the section between max. and min. levels is divided into a plurality of intermediate levels to be detected, the detection positions of the lateral sides are detected as widths of a unit corresponding to the sections smaller than the arranging widths of the photodiodes 21a, 21b. Therefore, register shift quantity can be detected from the extremely small register mark on printing paper. |
