Color Quality Optimization at the Printing Press: On-line Controls for Paper Mill, Coater, and Pressroom, 1996 New Printing Technologies Symposium Proceedings

Sanford I. Shapiro - Honeywell Inc.

The use of color printing for an increasing number of applications has motivated many changes to the manufacture of paper and paperboard. In addition to traditional basestocks, now newsprint and packaging grades such as linerboard and beverage carrier stock are also being coated and color printed. “Plain brown boxes are no longer brown and plain.” High quality and productivity at reasonable cost is made possible by new technologies. Automated color control at the printing press is the major subject of this report. However, it is necessary to keep in mind that optimizing color quality also requires proper basestock and coating. Technologies used in the paper mill include on-line measurements, automatic controls, and reporting systems for process, productivity, and quality information. These facilitate achievement of IS0 certification. Measurement and controls are available for basestock and coated papers and paperboard. Parameters include uniformity of basis weight, moisture, formation, caliper, ash content, opacity, brightness, gloss, color, smoothness, and coat weight. In commercial web offset printing, on-line closed-loop color control is a new technology now available. It is used to optimize print color quality, speed up make-ready time on the press, help maintain high operating speed, and reduce costs for