Patent ID: 7130084

Claim:
A electrophotographic apparatus for reproducing a picture by expressing a gradation of the picture by use of halftone spots which are each formed by dot pictures within a plurality of pixels, said electrophotographic apparatus comprising: a picture reproducing engine for forming the dot pictures by attaching toner to virtual dot areas each within the pixel; and an image processing unit for causing (i) growth of halftone spots of a first group in a first data range of input image data to increase a gradation of the dot picture, and (ii) growth of halftone spots of a second group in a second data range of the input image data, which is adjacent to higher gradation level side of said first data range to further increase the gradation of the dot pictures; wherein a density of the halftone spots of said second data range is larger than a density of the halftone spots of said first data range, and wherein said image processing unit generates virtual dots small enough to fail to form dot pictures of toner in halftone spot areas other than said halftone spots of said first group in said first data range of the input image data.