Image processing apparatus and image processing method for suppressing image degradation caused by a printing position fluctuation

An image processing method for forming an image by executing N (N is an integer not less than 2) printing scans for a single region on a printing medium comprising the steps of:

• a readout step of controlling a readout unit to read out image data of a region corresponding to a printing scan of interest from input image data;
• a print data generation step of controlling a print data generation unit to generate print data which is used in the printing scan of interest from the image data of the region read out in the readout step by halftone processing;
• and
• an obtaining step of controlling an obtaining unit to obtain position fluctuation information,
• wherein the position fluctuation information indicates a position shift amount from an ideal position in a direction of conveyance of a printing medium for the printing scan of interest, and
• wherein in the readout step, a readout position of the region corresponding to the printing scan of interest is controlled in accordance with the position fluctuation information.