Fixing device of an image forming apparatus that utilizes edge detections for heat shield positional determinations

摘要

A fixing device includes: a fixing member; an opposing member that provides a fixing nip with the fixing member; a heating unit that heats the fixing member; a heating area changing member that moves to change a heating area of the fixing member heated by the heating unit; and a position detection sensor that detects a position of the heating area changing member. The fixing device controls a stop position of the heating area changing member based on detection by the position detection sensor. The single position detection sensor detects the position of the heating area changing member both when the heating area changing member is moving from a preset reference position to an arbitrary position and when the heating area changing member is moving back from an arbitrary position to the reference position.