Patent ID: 8705128

Claim:
An image processing device for processing image data which indicate an image by a gradation value for each pixel, the image processing device comprising: an image data input unit configured to input the image data; a dot data generator configured to perform processing for generating dot data which indicate the presence or absence of dot formation from the image data; and a dot data output unit configured to output generated dot data, the dot data generator including an edge determination unit configured to determine whether a pixel included in the image data is an edge pixel for which the difference in gradation value in relation to an adjacent pixel is equal to or greater than a predetermined value, and a determination value adjustment unit configured to compare a gradation value of the pixel included in the image data to a threshold value of a dither mask prepared in advance, and adjust, using a first value range, a determination value, in the case that the pixel is determined to be the edge pixel by the edge determination unit, the first value range being smaller than a second value range used for adjusting a determination value for a non-edge pixel, the dot data generator performing an error diffusion process of the image data by using the adjusted determination value, and generating the dot data.