Patent ID: 6908173

Claim:
A bi-directional printing apparatus that bi-directionally prints images on a print medium during forward and reverse main scanning passes in accordance with print image signals, the printing apparatus comprising: a print head configured to print dots at each pixel position on the print medium; a main scanning drive mechanism configured to effect bi-directional main scanning by moving at least one of the print medium and the print head; a sub-scanning drive mechanism configured to effect sub-scanning by moving at least one of the print medium and the print head; a head driver configured to supply drive signals to the print head to effect printing on the print medium; and a controller configured to control bi-directional printing, the controller including a printing position adjuster that uses a bi-directional printing position adjustment value to reduce printing positional deviation arising between the forward and reverse main scanning passes, wherein the printing position adjuster includes: a first memory configured to store a reference correction value for correcting the printing positional deviation arising between the forward and reverse main scanning passes with respect to specific reference dots formed by the print head, a second memory configured to store a relative position correction value prepared beforehand for correcting the reference correction value with respect to a bi-directional printing position deviation, and an adjustment value determination section configured to determine the bi-directional printing position adjustment value, the adjustment value determination section having at least a first adjustment mode in which the bi-directional printing position adjustment value is determined by correcting the reference correction value with the relative position correction value.