Patent ID: 8472851

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; a light receiving unit that receives light, and outputs a signal according to an amount of received light; a conveyance unit that transports the printing medium; a conveyance control unit that controls the conveyance unit so that the toner image is transferred to a predetermined position of the printing medium, based on the signal outputted by the light receiving unit; a determination unit that determines a reduction of an amount of light reflected by the image carrier based on the signal outputted from the light receiving unit when the light receiving unit receives the light reflected by the image carrier, while said image forming apparatus is sequentially forming a plurality of toner images and a plurality of pattern images on the image carrier; and a light-power control unit that increases a light amount of the light emitted from the light-emitting unit in accordance with the determination result of the determination unit while said image forming apparatus is sequentially forming the plurality of toner images and the plurality of pattern images on the image carrier.