Patent ID: 8494413

Claim:
A fixing device comprising: a fixing device body that is adapted to attach to and detach from an apparatus body of a double-sided image forming apparatus which comprises a return passage through which a recording medium is returned to an image forming position in order to form an image on both sides of the recording medium, and of a single-sided image forming apparatus which does not comprise the return passage; a fixing member that is provided in the fixing device body and that fixes an image to the recording medium; and a first attachment section that is provided at a return passage side in the fixing device body; and a passage surface member that is adapted to attach to and detach from the first attachment section, and comprises a passage surface of an introduction passage through which a fixed recording medium on which an image has been fixed by the fixing member is introduced into the return passage, wherein the passage surface member is attached to the first attachment section to form a double-sided image forming apparatus and is detached from the first attachment section to form a single-sided image forming apparatus without changing the fixing device body.