| 摘要 |
PURPOSE:To prevent erroneous discrimination, by writing reference value data again when the speed difference between print running information for taking-in of reference value data and print speed information for taking-in of check value data exceeds a prescribed value. CONSTITUTION:An image sensor camera 1 scans the surface of a print P, and density information of each picture element obtained by this scanning is converted digitally by an A/D converter 2, and a reference value is stored in a memory 3, and a detected value is stored in a memory 4. A rotary encoder 5 is attached to the rotation shaft or the like of a rotary drum and forms a prescribed number of pulses at every rotation of the rotary drum, and these pulse are measured in a prescribed time to detect the speed of the rotary drum. This speed information for write of reference value data is stored in the memory 3 and is compared with speed information for write of check value data; and if they are different from each other by a prescribed value or more, reference value data is rewritten, thus preventing erroneous discrimination due to the speed difference. |
