System for maintaining ink density

摘要

PCT No. PCT/US94/11388 Sec. 371 Date Jul. 16, 1998 Sec. 102(e) Date Jul. 16, 1998 PCT Filed Oct. 11, 1994 PCT Pub. No. WO95/11806 PCT Pub. Date May 4, 1995The invention is a system for a printing press which maintains the density of the colored ink put down on a moving paper web. The system includes a scanning device having a strobe light for illuminating a color patch in a color bar which runs transversely across the web, a camera for photographing the illuminated color patch and a step motor for moving the scanner incrementally across the web. Actuation of the scanner is timed through a microprocessor using input from an optical sensor and encoder. A signal is sent from the camera to a computer which determines the density of the color patch shot. A work station calculates how much the existing ink control console must be adjusted to maintain density and a command signal is sent from the work station to the console to effect the adjustment. Lateral movement of the scanning means is offset or adjusted dependent on signals received from edge detectors, located at the press infeed and at the closed loop roller stand, to compensate for web lateral movement or distortion.