Quadtech, Inc.

Chia-Lin Chu

John C Seymour

Jeffrey P Rappette

Jeffrey W Sainio

Bradly S Moersfelder

Karl R Voss

Michael A Gill

Amit Sharma

Frank N Vroman

A method is disclosed for determining ink key control settings for a plurality of ink keys in a printing press. Each of the ink keys controls the amount of ink supplied to a roller and then to a respective ink key zone on a substrate to print an image. A press model relates image requirements to ink key control settings. The press model includes a gain and a respective offset associated with each ink key. The offset represents the amount a value represented by the ink key control setting varies from the actual ink key opening. The drift in the respective offsets of the ink keys is tracked by comparing control settings predicted by the press model with final control settings after a press job has been satisfactorily completed.

Ink key control in a printing press including lateral ink spread, ink saturation, and back-flow compensation

A method is disclosed for correction of the effects of ink back-flow and lateral flow in the inking system of a web-offset printing press. A plate coverage equation dependent on plate coverage is used to compensate for ink back-flow into the ink reservoir. An ink key distribution function is utilized to correct for the blurring effects of lateral ink spread caused by the action of vibrator rollers. A correction is also made for the ink saturation effect. The method is applicable to an ink key preset system.

Ink key control in a printing press including lateral ink spread, ink

A method for monitoring color of a printed image printed on a substrate, the method comprising the steps of: positioning a camera assembly to receive light reflected from the printed image on the substrate, the camera assembly including a structure for producing a signal; transmitting the signal from the camera assembly to a computer; and processing the signal in the computer to correct for the effects of scattered light reflected from the printed image.

System and method for monitoring color in a printing press

A control system is disclosed for controlling misregistration between the colors of an image printed on a web. The system includes an imaging device such as a camera or group of cameras, a processor, and image conversion circuits coupled to the processor. The system detects print color misregistration based upon the signals produced by the imaging device as a result of scanning the printed image. The conversion circuits convert the signals to signals usable by the processor to determine the color densities of the various colors within the image. These on-press color densities are compared with reference color densities stored in a memory of the processor, wherein the reference color densities may be generated from a source such as the printing plates used to print the image for which misregistration is being monitored. Based upon the phase correlation of the on-press images with the reference images, a processor operates to produce registration offset values between the printed colors and controls a print controller which adjusts the print units such that the colors of the printed image are placed into registration.

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Brookfield, WI, United States of America

Chia-Lin Chu