Image forming apparatus and image forming method

An image forming apparatus, comprising

• a transfer belt;
• a forming unit configured to form an image-misregistration detection pattern of a plurality of colors on the transfer belt;
• a detection unit configured to detect the image-misregistration detection pattern formed on the transfer belt;
• and
• a correction unit configured to correct an image misregistration of an image of each of the plurality of colors based on a detection result of the image-misregistration detection pattern by the detection unit;
• and
• a drive system configured to drive at least the transfer belt;
• a determination unit configured to detect a difference amount between a pattern interval of the image-misregistration detection pattern formed on the transfer belt and a pattern interval serving as a reference value for each color, and determine that an abnormality has occurred in a driving state of the drive system, in response to the difference amount being equal to or greater than a predetermined threshold value;
• and
• a notification unit configured to notify occurrence of the image misregistration when the determination unit determines that the driving state of the drive system is abnormal, based on the difference amount of any one of the plurality of colors.