Patent attributes
The invention describes an image forming apparatus having a cartridge configured to be removably attached to a main body. The cartridge has a rotational body positioned within the cartridge and an extension portion protruding outward from the rotational body in an axial direction. The device body has a main body, which has a driving member that rotates the rotational body and the extension portion, a detecting unit for detecting a movement of the extension portion, and a determining unit for determining a type of the developer cartridge using either a time elapsed between a time in which the driving member begins driving the rotational body and a time in which the detecting unit detects the movement of the extension portion, or a drive amount of the drive device occurring during an elapsed time.
