When a cleaning operation is performed, a controller of an image forming apparatus controls to emit a light beam from a light emitting window so as to form a stripe image in a predetermined position of an intermediate transfer member so as to form a image defect part in the stripe image, which occurs when a cleaning member moving in a reciprocating manner in a main scanning direction along the light emitting window blocks the light beam. In addition, the controller detects the image defect part by a density detecting member. When a predetermined number of image defect parts are not formed in the predetermined position in the period from start to end of the cleaning operation, the controller determines that the cleaning member is within the scanning range of the light beam.