| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a fixing device having a rotary detection mechanism for accurately detecting rotation of a roller even when tooth jumping occurs due to failure in engagement of gears and to provide an image forming apparatus provided with the fixing device.SOLUTION: A rotary detection mechanism has a first sensor and a second sensor arranged so that spacing from the first sensor is narrower than spacing from a shielding plate on an upstream side of the first sensor in the rotational direction of an actuator gear. A heated rotary body is determined not to be normally rotating when one of combinations of a first and a second pattern, the second and a third pattern, the third and a fourth pattern, and the fourth pattern and the first pattern is repeatedly detected for a plurality of times in this order continuously from: a first pattern having both optical paths of the first sensor and the second sensor shut off; a second pattern having only the optical path of the first sensor opened; a third pattern having both the optical paths of the first sensor and the second sensor opened; and the fourth pattern having only the optical path of the second sensor opened.</p> |
