Image forming apparatus that forms color images on recording sheet based on image information

An image forming apparatus, comprising:

• a plurality of image forming units;
• a transfer belt onto which a plurality of images formed by said plurality of image forming units are transferred;
• a detection unit configured to detect a position of said transfer belt in a belt width direction;
• a position adjusting unit configured to adjust the position of said transfer belt in the belt width direction according to a detected position detected by said detection unit;
• a calibration unit configured to calibrate an adjustment amount for adjusting color registration based on a detected position of patterns formed onto said transfer belt by said image forming units;
• a registration adjusting unit configured to adjust image forming positions of said image forming units based on the calibrated adjustment amount;
• and
• a control unit configured to, during formation of the patterns and during detection of the formed patterns, control said position adjusting unit not to adjust the position of said transfer belt in the belt width direction according to the detected position of said transfer belt.