Adjustment of misalignments of recording positions during bi-directional printing

Claim 1

A printing apparatus comprising a print head that has a plurality of nozzle groups each including a plurality of nozzles for ejecting an identical color, the printing apparatus having a bi-directional printing function of performing main scanning for moving the print head relative to a printing medium and sub scanning for moving the print head relative to the printing medium in a direction that transverses a direction of the main scanning, and ejecting ink from nozzles onto the printing medium on each of forward passes and backward passes of the main scanning of bi-directional movement to form dots on the printing medium, the printing apparatus comprising: a position adjustment value storage that stores a position adjustment value for reducing misalignments of dot forming positions between forward passes and backward passes of the main scanning; a position adjuster that adjusts dot forming positions along the main scanning direction during the bi-directional printing based on the position adjustment value stored in the position adjustment storage; a print head fixed to the printing apparatus, comprising an ink cartridge mount that is configured to mount one or more ink cartridges thereon, wherein each of the one or more ink cartridges comprises: an ink set including a combination of at least two ink tanks, each containing ink to be supplied to each of the nozzle groups, wherein each ink set includes at least one separable ink tank which is separable from the print head, such that in a first ink set of the printing apparatus, at least the separable ink tank is replaceable with another ink tank containing a different type of ink, thereby changing combination of ink tanks therein to form a second ink set, without replacing the print head; the printing apparatus is configured to use a first bi-directional print mode that selectively uses inks included in the first ink set and a second bi-directional print mode that selectively used inks included in the second ink set so that a combination of inks used in the first bi-directional print mode is different from a combination of inks used in the second bi-directional print mode, the position adjustment value storage is configured to store a plurality of position adjustment values including a first position adjustment value for the first bi-directional print mode and a second position adjustment value for the second bi-directional print mode, and the position adjuster selects a position adjustment value for a bi-directional print mode used by the printing apparatus out of the plurality of position adjustment values to adjust dot forming positions; wherein each of the one or more ink cartridges further comprises a memory which stores information including types of ink contained therein, wherein the printing apparatus further comprises: a reader, which reads out information stored in the memory of the one or more ink cartridges, and a print mode selector which specifies an ink set available to the printing apparatus according to the information read out by the reader, and which selects a bi-directional print mode according to the specified ink set; and wherein the position adjuster selects the position adjustment value according to the selected bi-directional print mode.