Color image forming apparatus and color image forming method

A color image forming apparatus comprising:

• a plurality of image forming units that form a plurality of color-component images;
• a first conveyance unit that conveys a recording medium to locations corresponding to the respective image forming units;
• a color-shift-detection-image forming unit that selectively forms a color-shift detection image on the recording medium or the first conveyance unit;
• a color shift detector that detects color shift based on the color-shift detection image, which is selectively formed on the recording medium or the first conveyance unit by the color-shift-detection-image forming unit;
• a recording-medium color-shift correcting unit that performs color-shift correction based on color-shift detection information corresponding to the color shift on the recording medium;
• and
• a conveyance-unit color-shift correcting unit that performs color-shift correction based on an amount of change in the color-shift detection information corresponding to the color shift on the first conveyance unit, the amount of change being determined using the color-shift detection information corresponding to the color shift on the first conveyance unit, which is obtained after the recording-medium color-shift correcting unit performs the color-shift correction, as a reference.