Image forming apparatus and heat fixing device provided in the same

摘要

An image forming apparatus includes an endless belt, a heater, a first temperature sensor, and a second temperature sensor. The endless belt is configured to circularly move about a rotational axis extending in an axial direction. The endless belt has a center portion and end portions in the axial direction, and defines an internal space and an outer peripheral surface. The heater is configured to heat the endless belt. The first temperature sensor is positioned at the center portion and in the internal space. The second temperature sensor is positioned at one of the end portions and facing the outer peripheral surface.

主权项

1. An image forming apparatus comprising:
an endless belt elongated in a longitudinal direction, the endless belt having a center portion and end portions in the longitudinal direction, and defining an internal space therein and an outer peripheral surface; a heater elongated in the longitudinal direction and configured to heat the endless belt;
a rotation member configured to form a nip region between the endless belt and the rotation member, the endless belt being configured to move in a moving direction at the nip region, the rotation member and the endless belt being configured to convey a recording sheet in a conveyance direction;a first temperature sensor positioned at the center portion and in the internal space;a second temperature sensor positioned at one of the end portions and facing the outer peripheral surface;a thermostat;a cover member positioned in the internal space; anda plurality of ribs provided on the cover member, aligned in the longitudinal direction, and configured to guide the endless belt, each of the plurality of ribs facing the second temperature sensor in the conveyance direction with the endless belt interposed therebetween,wherein the plurality of ribs includes:
a first rib overlapping with the first temperature sensor when viewed from a first direction perpendicular to the longitudinal direction, wherein a dimension of the first rib in the longitudinal direction is smaller than a dimension of the first temperature sensor in the longitudinal direction;a second rib overlapping with the second temperature sensor when viewed from a second direction perpendicular to the longitudinal direction, wherein a dimension of the second rib in the longitudinal direction is smaller than a dimension of the second temperature sensor in the longitudinal direction; anda third rib overlapping with the thermostat when viewed from a third direction perpendicular to the longitudinal direction, wherein a dimension of the third rib in the longitudinal direction is less than a dimension of the thermostat in the longitudinal direction.