Patent ID: 8730523

Claim:
An apparatus comprising: an image processing unit configured to perform quantizing processing of image data, which has a plurality of rasters each of which is formed with a plurality of pixels, by an error diffusion method to generate recording data for each raster, wherein the image processing unit is capable of performing quantizing processing of image data for N colors; a first control unit configured to perform a control of writing error data, which is diffused from the raster to which a pixel that has been subjected to the quantizing processing by said image processing unit belongs, in a first storage unit, or a control of writing error data, which is diffused from the raster to which a pixel that has been subjected to the quantizing processing by said image processing unit belongs, in a second storage unit; a second control unit configured to perform a control of reading error data, which is to be diffused to the raster to which a pixel that is to be subjected to the quantizing processing by said image processing unit belongs, from the first storage unit, or a control of reading error data, which is to be diffused to the raster to which a pixel that is to be subjected to the quantizing processing by said image processing unit belongs, from the second storage unit; and a third control unit configured to cause the image processing unit to perform multiple times quantizing processing in a case where the image processing unit performs quantizing processing of the image data for colors more than the N colors, wherein the image processing unit performs first processing for generating the recording data from the image data of a first color group and second processing for generating the recording data from the image data of a second color group alternately for each band in a case where the image processing unit performs quantizing processing of the image data for colors more than the N colors, and in a case where said image processing unit terminates the quantizing processing for a given band that is formed by arranging a predetermined number of the rasters, said first control unit performs the control of writing the error data, which is to be diffused to the raster that belongs to a next band to the given band, in the second storage unit, and in a case where said image processing unit performs the quantizing processing for the next band, said second control unit performs the control of reading the error data, which is to be diffused to the raster that belongs to the next band, from the second storage unit.