An image forming apparatus include an image forming device, an image bearer, a transferrer, a cleaner, and an adhesion amount detector. The image forming device forms, on the image bearer, a toner image to be transferred to a recording medium and a toner image pattern to be input to the cleaner without being transferred to the recording medium. The cleaner cleans the image bearer. The adhesion amount detector detects a toner adhesion amount of the toner image. The toner image pattern is a belt-shaped pattern elongated in an orthogonal direction orthogonal to a traveling direction of the image bearer and having a greater amount of toner input to a portion of the cleaner corresponding to a position of the adhesion amount detector in the orthogonal direction than that input to a portion of the cleaner not corresponding to the position of the adhesion amount detector in the orthogonal direction.