| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that it takes a long time for error diffusion processing, when half-toning using a dither mask is combined with half-toning by error diffusion method.SOLUTION: A printer includes a first determination unit for determining whether or not the gradation value of each of several pixels satisfies predetermined conditions, a second determination unit for determining whether or not a dot is formed in at least one of a plurality of pixels, by applying different conditions based on the determination results from the first determination unit, and an error calculation unit for calculating gradation error occurring due to the determination results from the second determination unit, in unit of a block consisting of a plurality of pixels, and distributing the error thus calculated to unprocessed pixels. With such an arrangement, error diffusion processing can be carried out at high speed, when a dithering method and an error diffusion method are used in combination.SELECTED DRAWING: Figure 3 |
