| 摘要 |
<p>An apparatus to control the registration between a printed web (5) of material and a downstream web processing station (4) at which the printed web is, for example, cut, folded, cut and folded, or punched, at a particular location with respect to the printing on the web comprises a length registration station (2) in the web path between a printing station (1) and the web processing station (4), a print detector (3) along the web path between the length registration station (2) and the web processing station (4) to monitor the passage of printing on the web, an encoder (7) coupled to the web processing station (4) to provide an output signal indicative of the operation of the web processing station (4) and a control unit (6) which receives the output from the print detector (3) and the output signal of the encoder (7) and which provides an error output signal indicative of the difference in phase between the two. The error output signal from the control unit (6) causes the web path length through the length registration station (2) to vary to compensate for any error in the registration of the printing on the web (5) resulting from variations in the printed repeat length in the length of web extending between the printing station (1) and the print detector (3). The apparatus also includes further registration means (12,13 and 14, or 15) operated in dependence upon the output of the control unit (6) to compensate for any error in the registration of the printing on the web (5) resulting from variations in the printed repeat length in the length of web extending between the print detector (3) and the web processing station (4).</p> |
