Patent ID: 8016380

Claim:
An ink jet printing apparatus comprising: a frame; a bridge extending transversely across the frame and defining a position of a printing station relative to the frame; a feed system configured to advance a substrate longitudinally relative to the frame through the printing station; a printhead moveable transversely across the bridge to print a row of an image across the substrate at the printing station; a motion system connected to the bridge and configured to move the printhead longitudinally relative to the frame; a controller operable to activate the feed system to index the substrate longitudinally a predetermined distance through the printing station; a web position measurement device mounted to the bridge and operable to measure, and communicate to the controller a signal corresponding to, an actual distance moved by the substrate through the printing station during the indexing of the substrate; the controller being operable to activate the motion system, in response to the signal to move the printhead longitudinally, relative to the indexed substrate, a correction distance corresponding to the predetermined distance less the actual distance moved by the substrate during the indexing of the substrate; the bridge having a carrier transversely moveable thereon; the printhead being longitudinally moveable relative to the carrier; the carrier having a motor mounted thereon and connected to the printhead, the motor being operable to move the printhead relative to the carrier along the longitudinal direction of the substrate in response to the activation of the motion system to adjust the longitudinal position thereof relative to the substrate at the printing station; and the controller being operable to activate the motion system to operate the motor to move the printhead longitudinally relative to the bridge to thereby move the printhead longitudinally the correction distance relative to the substrate.