| 摘要 |
<p>A web-feeding machine used to provide a continuous supply of material having successive labels and registration marks printed serially thereon includes an assembly for splicing the material from a ready web to the material severed from a running web. The splicing assembly has a response time T after being actuated by a control system. The control system comprises a driving circuit for electromechanically actuating the splicing assembly, a scanner positioned adjacent the material to provide a signal in response to the presence of a registration mark, and an encoder for providing a fixed number of pulses proportional to a corresponding length of the moving material. The control system also comprises a control circuit connected to the scanner, the encoder and the driving circuit. The control circuit counts the number of encoder pulses Bo between successive scanner signals and then decrements from that number Bo to zero. In addition, the control circuit provides a time delay To preset to approximate the response time T and then decrements to zero from a preset number D after the time delay To has expired. When the control circuit reaches zero, it stores a decremented value X representing the contemporaneous number read while decrementing from Bo to zero. The control circuit then decrements from the value X and provides a splice signal SS upon reaching zero. Finally, the driving circuit energizes the splicing assembly in response to the splice signal SS to accomplish a splice-in-register.</p> |
