Color image printing apparatus capable of eliminating moire pattern

Abstract

In a color image printing apparatus, image data is printed on a recording paper by using a thermal printing head through ink ribbons constructed of cyan, magenta, and yellow-colored ribbons. A single pixel of the image data is formed by a preselected dot number of areas. Within this area, the cyan, magenta, and yellow colors are printed out by dot numbers corresponding to density data of the respective colors. The cyan color data is printed out in such a way that while the density data thereof is increased, the dot number is successively increased from a predetermined printing position within this area. The magenta and yellow color data are printed out in such a manner that while the density data thereof are increased, the dot numbers are successively increased from different printing positions other than the above-described cyan printing position. As a consequence, since the printing positions for the cyan, magenta, and yellow colors are not overlapped with each other within a single pixel area, neither a Moire pattern, nor color deviation occurs, so that a color print image with better image quality can be formed.