Patent ID: 8164793

Claim:
An image processing method, that uses a first printing element array and a second printing element array both ejecting the same kind of ink and which performs a plurality of printing scans over a unit area of a print medium to form an image on the unit area, comprising: a data storage step to store multivalued image data corresponding to the unit area; a first distribution step to distribute, based on print volume information stored in a first print volume storage unit, the multivalued image data for a Kth printing scan over the unit area to a first plane for the first printing element array; a second distribution step to distribute, based on print volume information stored in a second print volume information storage unit, the multivalued image data for a Kth printing scan over the unit area to a second plane for the second printing element array; a first conversion step to convert the multivalued image data distributed to the first plane by said first distribution step into binary print data; a second conversion step to convert the multivalued image data distributed to the second plane by the second distribution step into binary print data; a step to execute the Kth printing scan over the unit area according to the print data by activating the first printing element array and the second printing element array in that order; a first information generation step to, after the binary print data is generated by said first grayscale level reduction step, update the print volume information on the unit area according to the generated print data and store the updated print volume information in the second print volume storage unit; and a second information generation step to, after the binary print data is generated by said second conversion step, update the print volume information on the unit area according to the generated print data and store the updated print volume information in the first print volume storage unit.