Image processing device, image forming device incorporating the same, and storage medium for storing program used thereby

Abstract

Corrected values C , M , and Y corrected in a quasi-grayscale processing section of an image forming device by an error diffusion technique performed for each channel are evaluated in threshold value sections provided for individual channels, so as to determine whether or not they are greater than threshold values. If an overlapping CMY dot formation detector section detects that the density is higher than the threshold value in all of the three channels, a minimum density channel identifying section instructs a first quantized value substitution section and varies the outputs from the threshold value sections, so that the output in the channel with the lowest density has a value that does not represent dot formation. As a result, overlapping dot formation for the three channels is interrupted. Consequently, an image processing device capable of restraining occurrence of dark blotches and decrease in saturation can be offered without losing dot balance between channels even when a quasi-grayscale process is executed for each channel.