To prevent characters from being faint color and lines from being irregular when an image is formed by using a spot multiplex system.
When resolution of image data is converted into resolution of a printer, characters or lines are included in pixel ares for conversion (S2206, S2207) and whether density is lower than a predetermined threshold is judged (S2208, S2209). In the case of the characters or lines and that it is not low density, weighted average of pixels in a fixed areas is considered as a pixel value after resolution conversion. In other cases, the resolution is converted by thinning processing (S2210). As a result, since resolution of the characters and the lines with low density is converted by the thinning processing, corrosion of peripheral density to a character area is prevented by weighted average.
COPYRIGHT: (C)2008,JPO&INPIT
MISAWA REIJI
Shiro Takayanagi
Yasuhiro Otsuka
Shuji Kimura
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