Temperature detector, image forming device having temperature detector, and contamination detection method for temperature detector

摘要

A temperature detector has: an infrared sensor located so as not to be in contact with a measured object; an infrared transmission filter which is located between the infrared sensor and the measured object so as to block the infrared sensor from the measured object, and through which infrared rays emitted from the measured object pass; and a distance changer for changing a distance between the measured object and the infrared transmission filter, wherein the infrared sensor is provided so as to detect the infrared rays, which have passed through the infrared transmission filter, to detect a temperature of the measured object even when the distance is changed by the distance changer.