An image forming apparatus having an image forming unit for forming toner images on an image carrier, a transfer unit for transferring an image on an image carrier onto a transfer medium, a detecting unit for detecting a toner image for detection on the image carrier, and a cleaning unit having a cleaning member that comes in and out of contact with the surface of the image carrier, wherein the cleaning unit is disposed downstream of the detecting unit and upstream of the transfer unit in the traveling direction of the image carrier, and the cleaning member is brought in contact with the image carrier when removing a toner image for detection on the image carrier.