Adaptive Control Methods for Web-Offset Inking

New adaptive control methods for offset inking have been developed at the Technical Research Centre of Finland. In early control procedures, the nonlinear print density was used as a print quality output, but the modified optical intensity gives a more stable performance for the control system. The ink consumption profile is determined using a new plate scanner and the inking screws are preset corresponding to the image distribution across the web. The number of optical sensors can be reduced by interpolation at blind control zones, and the control interval may vary from 20 to 40 revolutions.