| 摘要 |
PROBLEM TO BE SOLVED: To print a preferable image without generation of vertical stripes even in the case of an even half tone image while maintaining the quality of the output image of the text and the image data as in the conventional technique in a simple configuration. SOLUTION: In the case the main scanning direction resolution of a printer engine is four times as mush as the resolution of an original image, a pixel of the original image corresponds to four recording pixels in the main scanning direction of the printer engine. The same continuous three pixels in the main scanning direction in adjacent two lines (n line, n+1 line) are compared. In the case the density change is the same, the pixel of interest at the center of the three pixels in the n+1 line is recorded using a four recording pixels pattern with a small growth rate for reducing the density. In the case the same situation arises again, for example, in the case of the same change in n+2, n+3 lines, generation of stripes in the sub scanning direction can be prevented while maintaining the density of the entire image by using a four recording pixel patterns with a larger growth ratio of a pixel of interest. |
