| 摘要 |
A continuous clear surfaced web adapted to be fed from a supply roll thereof for a converting operation thereon is preprinted with a succession of identical repeat patterns extending over the entire width of the web. Each pattern consists of areas which contain printed matter and at least one longitudinable discontinuous area or segment which, except for the presence of a printed register mark therein, is clear and unprinted. A photo sensitive scanner is directed at the register mark track of the feeding web for detecting the register marks and controlling in accordance therewith the timing of an associated machine operation, such as web splicing, so as to be performed in register with the web pattern. The operation of the scanner is controlled by a digital reset counter of pulses fed from a pulse generator driven by the web feeding mechanism. The counter is reset to zero upon the detection of each register mark. It is initially preset to a number during the count of which the scanner is deactivated and after the count of which the scanner is activated. The number preset in the counter corresponds to the length of the register mark track starting from one register mark and continuing up to the segment of clear track containing the next register mark. The counter thus gates the operation of the scanner so as to detect only register marks and not to misread other printed matter lying in the scanned track as a register mark. |
