| 摘要 |
PROBLEM TO BE SOLVED: To prevent image quality from being deteriorated even when a density sensor breaks down by providing a density sensor fault decision means deciding whether the density sensor normally acts. SOLUTION: By turning on the power source of an engine, the self-diagnosis check of an image forming device main body is started. When abnormality does not exist, the temperature of a fixing unit 107 is raised and a density control mode is started during raising the temperature. After starting the density control mode, an image carrier 100 is irradiated with light in a state where the density sensor 113 is energized. By reading the output signal of reflected light from the image carrier 100, the fault of the sensor 113 is diagnosed. In the case of deciding that the sensor 113 breaks down, such a situation is judged as a state where appropriate image quality stabilizing control is not performed. Then, the actuation of a device main body is stopped, and the succeeding start-up processing of the image forming device is stopped and finished. By stopping the start-up processing when the sensor 113 breaks down, the image quality is prevented from being deteriorated. |
