| 摘要 |
PURPOSE:To normally operate a temperature overrising preventing device even at the time of starting a fixing device, and at the time of reaching a normal state by shielding the surroundings except a side opposite to the fixing roller of an energizing interrupting member, with a shield member. CONSTITUTION:A thermal fuse 11 as the energizing interrupting member, is arranged at a small gap from the periphery of the fixing roller 1, and simultaneously, the surroundings except the side opposite to the fixing roller 1 is covered with a cover 20 as the shield member. Thus, the thermal fuse 11 is protected from an air current inside a fixing unit, such as convection by the heat of the fixing roller 1 and wind by an exhaust fan, and an environmental temperature (surface temperature) is prevented from being lowered. On the other hand, when the temperature of the fixing roller 1 reaches a prescribed one, even at the time of starting, the thermal fuse 11 is disconnected, the energization of a heater 2 is interrupted. Therefore. even at the time of starting the fixing device, or even in the normal state after the start, the temperature overrising preventing device 24 is normally operated. |
