Eastman-kodak Company

Rodney Gene Mader

John J Saettel

Brian L Travis

Timothy John Young

John Ludwicki

Michael Patrick Fink

Donald R Allred

Gerald L Kelly, Iii

Cross-track stitch errors in an inkjet printer are reduced by printing test patterns for a plurality of in-track offsets. A first test pattern portion to be printed with a first jetting modules includes a uniform density region having a slot with a slot width. A second test pattern portion to be printed with a second jetting modules includes a bar having a bar width, wherein the uniform density region of the first test pattern portion and the bar of the second test pattern portion overlap in the cross-track direction and are printed with jets in an overlap region between the jetting modules. The printed test patterns are analyzed to determine a stitch score that represents a degree of alignment between the slot in the first test pattern portion and the bar in the second test pattern portion. An aim offset value is determined where the slot and the bar are aligned.

In-track stitching error correction

Image plane registration errors are corrected for a multi-channel printing system that prints on a continuous web of media. Nominal in-track line spacing are defined for each image plane, and are used to print lines of image data for each image plane. An in-track registration error is measured for a misregistered image plane in the printed image, and is used to determine an adjusted in-track line spacing that will bring the misregistered image plane back into registration in the in-track direction over a predefined correction time interval. Additional image data is then printed using the adjusted in-track line spacing during the correction time interval, after which image data is printed using a new in-track line spacing that is different from the adjusted in-track line spacing.

Registration correction for continuous printing

A method for adjusting an encoder pulse count delay in a printing system for printing on a continuous web of print media using first and second printheads. First and second encoders are provided at different positions along the media transport path. An initial encoder pulse count delay is provided for use in printing with the second printhead. An initial ratio of the first encoder pulse rate to the second encoder pulse rate is determined. At a subsequent time a subsequent ratio of the first encoder pulse rate to the second encoder pulse rate is determined. An adjusted encoder pulse count delay is determined by adjusting the initial encoder pulse count delay responsive to the initial ratio and the subsequent ratio and used to control printing by the second printhead.

Controlling a printing system using encoder ratios

A method for calibrating a multi-printhead printing system, the method includes the steps of employing an encoder to track movement of a media through the printing system; providing a first printhead that prints a first image plane that includes a first test mark at a first defined location on the media as the media moves relative to the first printhead; providing a second printhead that prints a second image plane that includes a second test mark at a second defined location on the media as the media moves relative to the second printhead; employing a first image capture device that captures an image that includes both the first and second test marks; determining an error factor based on the placement of the second mark relative to the first mark in the captured image; and creating a frequency-shifted pulse train of the encoder in which the frequency shift is based on the error factor; wherein the first printhead prints the first image plane in response to output of the encoder and the second printhead prints the second image plane in response to the frequency-shifted pulse train of the encoder.

Calibration system for multi-printhead ink systems

A method for calibrating a multi-color inkjet printing system includes using a 3&#xd7;2 test target array. The test target includes printing a first color three times in which two of the three colors are aligned along a first axis and the third is offset from the first axis and at a midway point between the other two test marks along the other axis. A second test color is aligned with at least one of the first colors along both axes.

Color to color registration target

A method for evaluating the stability of print module registration for a printer creates an innovative test pattern by forming two graphic images from two separate print modules. The graphic images include parallel graphic information and a desired intersection point. The graphic images are printed on by a pixel by pixel basis onto print media from the separate print modules. The resulting patterned image or test pattern is viewed to ascertain alignment based on the desired intersection point.

Growing community of inventors

Springfield, OH, United States of America

Rodney Gene Mader