| 摘要 |
<p>Device for determining and adjusting the position of a web In a device for determining and adjusting the position of a web (1), particularly the paper web of a web printing press, there are two sensor units (11, 12) which each have a light source (13) aimed at one edge of the web and a photoelectric sensor (14) which responds to reflected light. The sensor units cooperate with a reflector (16) which is disposed on the side of the web (1) facing away from the sensor units and which projects beyond the edges of the web. The output signals of the sensor units are supplied to a control unit comprising two comparators (27, 39), said control unit generating the adjusting signals for a device for adjusting the position of the web, said device comprising a stepping motor (4) and a rotating frame (3) for the web (1). The first comparator (27) of the control unit forms the difference of the two output signals of the sensor units (11, 12). Of these sensor units, at least one (11) may be coupled to the comparator (27) via a low-pass filter (23). If such a low-pass filter is not used, the device allows centralized control whereas the use of a low-pass filter provides web edge control. The second comparator (39) allows the supplying of control signals for the correction of the position of the web. The use of a stepping motor (4) makes it possible to use pulse trains both for control as well as for adjustment. The drive pulse trains required for adjustment may be generated from various points of the device where simple indication devices may also be disposed to state whether the device is in the optimum control range or not (Fig. 1).</p> |
