Quadtech, Inc.

Quad/graphics, Inc.

Quad/tech International

Jeffrey W Sainio

John C Seymour

Karl R Voss

H Richard Quadracci

Chia-Lin Chu

Jeffrey P Rappette

Alan D Lasecki

Randall W Freeman

Craig J Peglow

Timothy J Pulte

By inclusion of a register target within a colorpatch, a colorbar is used for controlling color register as well as controlling color density on a printing press.

Printing press register control using colorpatch targets

The invention relates to a system and method of eliminating wrinkling, tearing and web-breaks of a web in an offset printing press as the web contacts the chill rollers on start-up. The system operates to eliminate the wrinkling that generates the tearing. During startup, a spreader roller impinges the web, stretching out wrinkles. During acceleration of the press, when thermal contraction of the paper also achieves the desired stretching, the spreader roller is retracted to prevent smearing of ink on the web. Uneven pressure of the spreader is utilized to implement steering of the web to enhance web centering.

Anti-wrinkle system for a web offset press

The inertial drag of idler rollers in a web-offset press with independently driven drive rollers is compensated by successively advancing downstream rollers during speed changes. This prevents low-tension conditions on the web and subsequent web breaks. Compensation is made for inertial coupling to the idler rollers through the web. Tension control is utilized to stabilize web position during startups and splices.

Method and apparatus for controlling tension in a web offset printing

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.

Color registration system for 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 conversation circuits convert the signals to signals usable by the processor to determine the color densities of the various colors within the image. These color densities are compared with reference color densities stored in a memory of the processor, where 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 comparison of the color densities derived as a result of scanning the printed web, and the reference color densities, a processor operates to produce registration offset values between the printed colors which are used to control a print controller which controls the print units such that the colors of the printed image are placed into registration.

An apparatus for dispersing contaminants from the surface of a web moving in a processing direction within a web processing system, the web processing system including a web processing structure, the apparatus including a chill roll air bar disposed proximate to a surface of the web, for separating the contaminated air from the surface of the web before that surface of the web engages the processing structure.

Method for reducing chill roll condensation

Apparatus for reducing chill roll condensation

A system for generating indicia of registration error between the respective printing units of a web-fed, four-color printing press. An optical line scanner is disposed over a web to generate signals indicative of the brightness level of successive nominal pixels along a line transverse to the motion of the web. The respective printing units each generate registration marks on the web, the relative positions of which are indicative of the relative cyclical (rotational) and transverse (lateral) positions of the printing units with respect to the web. As the web moves past the scanners, successive line scans generated by the scanner provide the equivalent of a two-dimensional raster scan of a strip of the web centered on the expected center line of registration marks produced by the respective printing units. The centers of the respective registration marks are determined, and the cyclical (rotational) and transverse (lateral) positions of the printing unit adjusted, in accordance with deviations from expected relative positions. The use of symmetrical marks and, in particular, right-angled diamonds is disclosed for facilitating calculation of the center of the marks.

Web registration control system

A system and method for stabilizing a moving web within a printing press having one or more printing units cooperating to print an image on the web, including an air driven stabilizer structure disposed proximate to the printing units associated therewith for controlling the arc length of blanket follow between the web and one or more of the printing cylinders by creating a Bernoulli effect.

Bernoulli-effect web stabilizer

A system and method for generating indicia of registration error between respective, separately adjustable printing units of a printing press, the printing units cooperating to print an image on a moving web, the system being of the type comprising a photo-optical control, having a field of view and depth-of-field, for generating output signals indicative of a predetermined relative disposition of marks on a web passing through the field of view within the depth-of-field of the photo-optical control as the web moves in relation to the printing units, and processing circuits, responsive to the photo-optical output signals, for generating signals indicative of deviations of the registration marks printed by the printing units from the predetermined relative disposition; improved wherein:

A system for generating indicia of registration error between the respective printing units of a web-fed, four-color printing press. An optical line scanner is disposed over a web to generate signals indicative of the brightness level of successive nominal pixels along a line transverse to the motion of the web. The respective printing units each generate registration marks on the web, the relative positions of which are indicative of the relative cyclical (rotational) and transverse (lateral) positions of the printing units with respect to the web. As the web moves past the scanners, successive line scans generated by the scanner provide the equivalent of a two-dimensional raster scan of a strip of the web centered on the expected center line of registration marks produced by the respective printing units. The centers of the respective registration marks are determined, and the cyclical (rotational) and transverse (lateral) positions of the printing unit adjusted, in accordance with deviations from expected relative positions. The use of symmetrical marks and, in particular, right-angled diamonds, is disclosed for facilitating calculation of the center of the marks.

Growing community of inventors

Hartland, WI, United States of America

Jeffrey W Sainio