Image forming apparatus

An image forming apparatus which forms image on a print medium by using a plurality of color toners, said image forming apparatus comprising:

• an image carrier;
• a plurality of image forming units adapted to form toner images on said image carrier, wherein each of said plurality of image forming units forms different color toner image on said image carrier;
• a pattern formation unit adapted to cause said plurality of image forming units to form toner patterns on said image carrier in order to correct a relative registration error between the different color toner images formed on said image carrier;
• a detection unit adapted to include a light-emitting portion for emitting light to said image carrier and a light-receiving portion for receiving reflected light of the light emitted from the light-emitting portion;
• a correction unit adapted to correct the relative registration error between the different color toner images based on a detection result of said detection unit;
• and
• a light amount control unit adapted to control amount of light to be emitted from the light-emitting portion based on amount of light reflected from the toner patterns and amount of light reflected from said image carrier, in a case where the light-emitting portion emits light to the toner patterns and the image carrier, and the light-receiving portion receives the light reflected from the toner patterns and the light reflected from said image carrier.