US Patent 7832836 Ink jet printing apparatus and ink jet printing method

In an ink jet printing apparatus using many types of inks to execute bidirectional printing, when symmetrically arranged ejection opening rows for a cyan, magenta, and yellow inks are used in the print head, one-pass bidirectional printing is executed. On the other hand, if ejection opening rows for a black ink are used in addition to the above ejection opening rows, multi-pass printing is executed so that there are a number of dots formed with one application order for the black and other color inks and the same number of dots formed with another application order for the black and other color inks. This reduces the non-uniformity of the colors attributed to the difference in application order.