Patent ID: 7255417

Claim:
A method of calibrating ink amount for a printer that comprises a printing head unit having a plurality of same ink nozzle arrays for ejecting same ink to form ink dots on a printing medium while scanning the printing head unit in a main scanning direction, the method comprising: (a) obtaining an ink ejection amount error for each of the plurality of the same ink nozzle arrays; (b) identifying line sets on the printing medium, each line set consisting of a predetermined number of main scan lines that are adjacent to each other; (c) allocating pixels included in each line set to the plurality of the same ink nozzle arrays for recording; (d) determining a ratio of pixel counts allocated to the plurality of the same ink nozzle arrays with respect to each line set; (e) determining an average ink ejection amount error for each line set using the ink ejection amount errors for the plurality of same ink nozzle arrays; and (f) correcting ink amount data representing a print image on each main scan line of each line set using the average ink ejection amount error.