Patent ID: 8244165

Claim:
An image forming apparatus that forms a toner image and a pattern image for indicating a position of the toner image on an image carrier, and transfers the toner image on the image carrier to a printing medium, the apparatus comprising: a light-emitting unit that emits light for irradiating to the image carrier; an outputting unit that outputs a signal according to an amount of a received light; an identifying unit that identifies a light reflected by the pattern image and a light reflected by the image carrier based on the signal outputted by the outputting unit; a light-power control unit that controls an amount of light of the light-emitting unit based on a first signal and a second signal, the first signal being outputted by the outputting unit at a first timing when the outputting unit receives the light reflected by the image carrier, the second signal being outputted by the outputting unit at a second timing when the outputting unit receives the light reflected by the image carrier, and the second timing being after the first timing; and a determination unit that determines the first signal based on a plurality of signals outputted by the outputting unit when the outputting unit receives the light reflected by the image carrier, and during a period between when the apparatus starts to form pattern images on the image carrier and when the outputting unit receives the light reflected by a predetermined number of the pattern images.