Patent ID: 6978045

Claim:
An image processor which processes grayscale image data on density levels of pixels, comprising: an edge judgment circuit which discriminates an edge direction of a target pixel from differences in density level between the target pixel and adjacent pixels thereof based upon the grayscale image data; and a density level determining circuit which determines grayscale density levels in a plurality of sub-pixels in the target pixel, where the target pixel is divided into the sub-pixels, in accordance with the density level of the target pixel and the edge direction of the target pixel discriminated by the edge judgment circuit, wherein the density level determining circuit comprises: a density controller circuit which sets density-level setting parameters for each of the sub-pixels in the target pixel in accordance with the edge direction of the target pixel discriminated by said edge judgment circuit; and a density-level setter circuit which sets the density level of each of the plurality of sub-pixels in the target pixel based upon the density level of the target pixel by using the parameters set by said density controller circuit; wherein the density level of the sub-pixels are determined by using a calculation for input gradation data with the parameters, the parameter for each pixel being determined based on the determined edge direction.