Patent ID: 7331648

Claim:
An ink jet recording apparatus comprising: a serial-type recording head comprising a plurality of nozzles to jet ink; a main scanning mechanism to reciprocate the recording head in a main scanning direction; a feeding device to feed a recording medium in a sub scanning direction perpendicular to the main scanning direction; and a control unit to control jetting of the ink from the nozzles of the recording head so that the recording head is driven with multi-phase drive to record with recorded pixel locations shifted at every drive phase switching by an integer times a pixel width of a recording resolution in the main scanning direction, and to perform recording by scanning the recording head a plurality of times with the recording medium fed by the feeding device; wherein the control unit controls the ink jetting such that a recorded pixel location X which indicates where a recorded pixel is located from a reference position in the main scanning direction when an arbitrary pixel as the reference position is set to 1 is given by X ={( i −1)× f+P −1 }×D +1, and a number of scanning S of the recording head is given by S=f×D×R p /R n or S=f×D×P n /P p where: i is a number of a pixel when counted from the reference position out of pixels recorded by the same nozzle in the main scanning direction, D is the shifted number of pixels in the main scanning direction at every phase of recorded pixels (by a unit of the number of pixels in the recording resolution), f is the number of head-drive phases, P is a drive phase number (a phase number allotted from P=1 to P=f in the order of drive, designating a drive phase to record a pixel at the reference position as P=1), S is the number of scanning of the recording head, R n is a resolution of the head in the sub scanning direction, R p is a recording resolution in the sub scanning direction, P n is a mean pitch between adjacent nozzles in the sub scanning direction, and P p is a recorded pixel pitch in the sub scanning direction.