| 摘要 |
<p>Web registration unit operates with one set of registration marks (3, 4, 5, 6) on the web and additional marks (7) located behind the first set. These extra marks are used for coarse and fine manual adjustment. Two closely situated monitoring points above the web comprise photoelectric receivers (9, 10) whose separation corresponds the registration distance between two printed marks (3). The distance between two neighbouring marks (3 to 6) or markings (7, 22) which are recognized as the change between free strip surfaces and an imprint, is measured and compared with a predetermined interval which is somewhat smaller than the distance between the first of one series of marks (3) and the marking (22) in front of it. Only when the measured distance exceeds the pregiven interval is a control signal generated.</p> |
