Ink-jet printing apparatus and ink-jet printing method

An ink-jet printing apparatus employing a printing head capable of ejecting an ink through a plurality of ink ejection openings associating with a printing scan, comprising:

• means for making said printing head to scan for N times with dividing a region to be printed by said printing head having plurality of said ejection openings by N which N is an integer greater than or equal to two;
• means for sequentially and relatively transporting a printing medium in a direction different from the direction of said scan, between said scans;
• a first control means for performing image formation for each of said divided scanning regions by driving said printing head using N kinds of thinning patterns in mutually complementary relationship;
• and
• a second control means for making the number of timings of scanning for completing image formation of a boundary portion adjacent other scanning region to be substantially smaller than N times, and performing scanning simultaneously with scanning for said adjacent scanning region.

An ink-jet printing method employing a printing head capable of ejecting an ink, comprising the steps of:

• a step for scanning said printing head for a plurality of times with respect to the same scanning region of a printing medium;
• a step for relatively transporting said printing medium between said scans in a direction different from a scanning direction of said printing head;
• a step for driving said printing head during said scan for performing printing of respective scanning region sequentially;
• and
• a control step for setting the number of times of scanning in a boundary portion in each scanning region adjacent to the other scanning region to be substantially smaller than that in regions other than said boundary portion, and effecting scan for said boundary portion simultaneously with scan of adjacent to the other scanning region.