Patent ID: 8477361

Claim:
An image data generating apparatus that generates image data used for printing an image on a unit area of a printing medium by a plurality of scans of a printing head, said apparatus comprising: an obtaining unit configured to obtain a plurality of M-valued image data corresponding respectively to one scan and another scan of the plurality of scans, where M is an integer; and a generating unit configured to generate first n-valued image data representing a gradation value of n values, where n is an integer less than M, corresponding to the one scan by executing an M value-to n value conversion process on M-valued image data corresponding to the one scan obtained by the obtaining unit, and generate second n-valued image data corresponding to the another scan by executing an M value-to n value conversion process on M-valued image data, the M-valued image data being data that is obtained by correcting a gradation value of a pixel in the unit area for the another scan on the basis of an n value of the pixel of the first n-valued image data.