| 摘要 |
PURPOSE:To mark an invariably correct position as a defect position by counting length measurement pulses from the operation of the 1st passage detector to the start of the operation of the 2nd passage detector and correcting an increase or decrease in the number of length measurement pulses due to the wear of a touch roller, an increase or decrease in steady slide, etc. CONSTITUTION:While a material 1 to be inspected is conveyed in a conveyance direction 2, the number nx of pulses is outputted 11 as a counting result at the time of an initial touch roller diameter in a period from the operation of the 1st passage detector 9 at the downstream conveyance side of a touch roller 4 to the start of the operation of the 2nd passage detector 10 further at the downstream conveyance side of the detector 9. At the time of a touch roller diameter after abrasion, on the other hand, the number n'x of pulses is outputted 11 as the counting result. For the purpose, a length measurement pulse correcting circuit 12 corrects length measurement pulses n' as shown by a specific expression and outputs the corrected length measurement pulse ne (=n) to a tracking circuit 7, so that the invariably correct defect position is marked regardless of the abrasion of the touch roller 4.
|
