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US 8,573,725 B2Granted
System and method for correcting stitch error in a staggered printhead assembly
AssigneeXerox Corporation
InventorsTrevor James Snyder, Jignesh P. Sheth
Life of this patent
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Abstract
An improved method of measuring relative positions of adjacent printheads in a printhead array has been developed. A pair of ink dashes is made with different colors of ink from adjacent printheads and an offset distance between the dashes is determined from color density measurements of the two dashes. The offset distance may then be used to adjust the stitch alignment of the two printheads.
Claims12
A system for evaluating printhead positions in an ink printing system comprising:
- a first printhead having a last ink ejector and a second printhead having a first ink ejector, the first and second printheads positioned adjacent to one another in a cross-process direction and configured to eject ink drops onto an image receiving surface, where ejected ink drops from the last ink ejector of the first printhead form a first ink dash having a first color and ejected ink drops from the first ejector of the second printhead form a second ink dash having a second color;
- and
- a controller operatively coupled to at least the first printhead and the second printhead, the controller configured to:
- operate the first printhead to form the first dash on the image receiving surface;
- operate the second printhead to form the second dash on the image receiving surface at a process direction position corresponding to a process direction position of the first dash;
- receive color image data of an area of the image receiving surface on which the first dash and the second dash were formed;
- identify a color density of a secondary color in the color image data, the secondary color corresponding to a color produced by the first dash and the second dash formed on the image receiving member;
- and
- identify an offset distance between the first and the second printheads by identifying a difference between the identified color density of the secondary color and a color density for a secondary color formed by a dash of the first color and a dash of the second color being separated by a predetermined offset distance.
6 more elements
A method of measuring positions of adjacent printheads in a printhead array comprising:
- operating an ink ejector in a first printhead to form a first dash on an image receiving surface, the ink ejector in the first printhead being a last ink ejector in the first printhead in a cross-process direction;
- operating an ink ejector in a second printhead to form a second dash on the image receiving surface, the ink ejector in the second printhead being a first ink ejector in the second printhead in the cross-process direction and the first and second printheads being adjacent printheads in a printhead array in the cross-process direction;
- receiving color image data of an area of the image receiving surface on which the first dash and the second dash were formed;
- identifying a color density of a secondary color in the color image data, the secondary color corresponding to a color produced by the first dash and the second dash formed on the image receiving member;
- identifying an offset distance between the first and the second printheads by identifying a difference between the identified color density of the secondary color and a color density for a secondary color formed by a dash of the first color and a dash of the second color separated by a predetermined offset distance;
- and
- moving one of the first printhead and the second printhead in a cross-process direction in response to the offset distance being at least a predetermined distance.
4 more elements
Dependencies are inferred from the claim text.