A printer controller comprising a rasterizing part for producing raster data as printing data, a skew correcting part for correcting the raster data for a skew error in accordance with a correction coefficient delivered form the color image forming device and indicating a skew error, a compression part for compressing the raster data corrected for the skew error so as to deliver the compressed raster data, and storing the compressed raster data in memory, an expansion part for expanding the compressed raster data so as to restore the raster data, and a magnification correcting part for correcting the raster data delivered from the expansion part, for a magnification error accordance with correction coefficient delivered from the color image forming device and indicating a magnification error. With this configuration, it is possible to eliminate the necessity of line memory.
