Lateral register control system and method

Abstract

A lateral register control system utilizing a reference lateral and circumferential mark pair preprinted on the web which is compared with a corresponding mark pair mounted on a drum coupled to the shaft of the print cylinder whose reference is to be controlled. The clock source being an encoder connected to the same print stand as laid down the reference marks on the web. The contents of the cylinder position counters always being slightly greater than the contents of the scanner difference counters and being counted up slightly before the scanner difference counters. Upon sensing a first reference mark on the web, the scanner difference counters are permitted to count. Upon the second reference mark being sensed the fine adjust counters are permitted to start counting. Upon the contents of the fine adjust counters equaling the value of operator setable fine adjust switches, an error pulse train is generated having an associated sign. The error pulse train is accumulated in a repeat counter and is terminated when the contents of the scanner difference counters equal the contents of the cylinder position counters. Said error magnitude may be averaged over several cycles or output directly to a digital analog converter which produces an analog error magnitude. This magnitude serves as the input to the motor control circuitry. Said motor control circuitry being operable to drive the print cylinder lateral position motor at a rate proportional to said analog error signal and in the direction indicated by the sign of said error signal.