Patent ID: 8837960

Claim:
An image forming apparatus comprising: an image carrier on a surface of which an image is formed and carries the image; a rotation device that has a plurality of image-forming devices each including a toner and forming a toner image on the surface of the image carrier with the toner, causes one of the image-forming devices to face the surface of the image carrier and to form the toner image, and rotates to change the image-forming device facing the surface of the image carrier; a detector that is attached to at least one image-forming device of the plurality of image-forming devices, and detects a quantity of the toner included in the at least one image-forming device, to output an analog signal representing the quantity; a transmission path that transmits the analog signal outputted by the detector, to the outside of the rotation device, and that includes a rotation terminal which is mounted on the rotation device and rotates together with the rotation device, and a contact terminal which is provided outside the rotation device, and contacts a surface of the rotation terminal to maintain continuity with the rotation terminal even when the rotation terminal rotates; and a correction section that corrects the analog signal transmitted through the transmission path according to a contact resistance between the rotation terminal and the contact terminal.