| 摘要 |
PROBLEM TO BE SOLVED: To perform power savable heating control without dew condensing on an optical means by detecting the surface state of the optical means. SOLUTION: A surface state detection sensor 21 is arranged out of an image area of a mirror 5, and an output signal is inputted to a heater control substrate 20 through a feeding cable to a scanner unit 4. A heater 19 is a cement heater of about a several tens of W, and generates heat by energizing AC power. The sensor 21 and the heater 19 heating the optical means and its control circuit 20 are energized for twenty-four hours by a system separate from a source system of an image forming device main body to be operated always. When a phenomenon called dew condensation occurs, a waterdrop is stuck onto a surface of an optical mirror 5, and a surface state, particularly, a reflectance is changed, and the output of the surface state detection sensor 21 is changed. When a prescribed output signal is lowered to a fixed ratio, the heater 19 is started to be energized, and the optical means is started to be warmed, and the dew condensation is released, and the energizing to the heater 19 is released when a certain extent time elapses after the prescribed signal returns to the value before a change start. |
