Hewlett-packard Development Company, L.P.

Dani Sagi

Craig Breen

A method for detecting and correcting misregistration between a plurality of separations printed by a printing apparatus, comprising: producing a calibration print output on a substrate, the calibration print output including at least one calibration pattern, wherein the at least one calibration pattern translates horizontal misregistration into a detectable indicator of misregistration in a process direction; detecting misregistration; and, performing a fine adjustment of the horizontal position of at least one of the separations using the at least one calibration pattern.

Horizontal color plane registration correction

A dual engine color printer has two print engines, one for printing each side of the sheet. Each engine comprises a single multi-color set of printing drums&#x2014;a set meaning a PIP drum, a blanket and an impression drum. A scheduling method is provided for imbalanced duplex printing of sheets in a print job, imbalanced meaning that the two sides of the sheets requires different numbers of colors. This conventionally leads to a situation in which one engine would have to wait until the other engine has finished. The method comprises feeding the sheets in sequence between the print engines, and alternating, over the sequence of engines, between printing the upside of a sheet followed by the down side for even sheets and the downside followed by the upside for odd sheets. Thus the two print engines are utilized full time and are not left idle while waiting for each other.

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Nes Ziona, Israel

Dani Sagi