Image forming apparatus capable of stably detecting temperature of fixing device regardless of orientation of the image forming apparatus

摘要

An image forming apparatus orientatable in either a first position or a second position, the second position being different from the first position in inclination with respect to a horizontal plane, including a fixing unit including a fixing roller and a pressurizing roller, pressing the pressurizing roller against a surface of the fixing roller to form a fixing nip, and thermally fixing a toner image on a recording sheet passing through the fixing nip; at least one temperature sensor detecting surface temperature of the fixing roller without contact with the surface; a heater heating the fixing roller; and a controller controlling the heater according to the surface temperature, thereby controlling the surface temperature, wherein a heat sensitive portion of the temperature sensor is located above a horizontal plane passing through a rotational axis of the fixing roller regardless of the orientation of the image forming apparatus.

主权项

1. An image forming apparatus that is orientatable in either a first position or a second position, the second position being different from the first position in inclination with respect to a horizontal plane, comprising:
a fixing device that includes a heating roller and a pressurizing member, presses the pressurizing member against a surface of the heating roller to form a fixing nip, and thermally fixes a toner image formed on a recording sheet passing through the fixing nip; at least one temperature detector that detects temperature of the surface of the heating roller without contact with the surface; a heater that heats the heating roller; and a controller that controls the heater according to the temperature detected by the at least one temperature detector, and thereby controls the temperature of the surface of the heating roller, wherein a detection point of the at least one temperature detector is located above a horizontal plane passing through a rotational axis of the heating roller regardless of whether the image forming apparatus is in the first position or in the second position; the image forming apparatus further comprising a switcher that switches a detection point of the at least one temperature detector between a first detection point and a second detection point according to whether the image forming apparatus is in the first position or in the second position; wherein the switcher serves as a movement mechanism that moves the at least one temperature detector according to whether the image forming apparatus is in the first position or in the second position.