| 摘要 |
PURPOSE: To monitor the web matching by projecting an image of an mark onto a detection station so that two axes may be traverse to the direction of web movement, and by determining the times at which equal areas of a mark are projected on either side of the areas. CONSTITUTION: When a matching mark 13 reaches a detection station 7, an image of the mark is projected onto a quadrant array 20. An output signal P represents the effect of a matching mark image on photo detectors 21 and 22 compared with images on photo detectors 23 and 24. A signal Q passes the intermediate zero position when a mark coincides with the center of an axis 25. A controller 6 measures the times t1 and t2 and computes the time t3 corresponding to the time which a fictitious line 37 is crossed with a matching mark traverse to the web direction 38. The computation is repeated by the controller 6 as per each mark 13-16 and the difference between the times t3 is computed. If there causes a difference, the correction value to minimize the time difference is determined by controlling the web speed. The deviations in the horizontal direction are measured by computing t1 and t2 . |
