Patent ID: 7740334

Claim:
A printing system comprising a carrier, a plurality of printhead modules carried by the carrier and a controller, each printhead module having at least one row of ink ejection nozzles, the printhead modules being abutted along the carrier so that the nozzle rows are continued in alignment across a joint between adjacent abutting printhead modules, each of the nozzles being configured to eject ink in response to fire signals from the controller, the controller being configured to: determine erroneous rotational displacement of each printhead module relative to the other printhead modules including relative pitch, roll and yaw; determine a correction factor that compensates for ink dot displacement by at least one of the nozzles due to the pitch and roll of at least one printhead module based on a thickness of media being printed and that compensates for ink dot displacement by at least one of the nozzles due to the yaw of at least one printhead module; and using the correction factor, alter the output of the fire signals to the nozzles so as to alter the ejection of ink dots to at least partially compensate for the rotational displacement.