Fixing device and image forming apparatus with a rotatable light shield

摘要

A fixing device includes a nip formation pad pressing against a pressure rotator via a fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The nip formation pad includes a base and a first thermal conductor sandwiched between the base and the fixing rotator at the fixing nip and having a first thermal conductivity greater than a basic thermal conductivity of the base. A first heater and a second heater are disposed opposite an inner circumferential surface of the fixing rotator to heat the fixing rotator. A rotatable light shield moves to a shield position where the light shield is interposed between the second heater and the fixing rotator to shield the fixing rotator from the second heater. The second heater is disposed at a location where the light shield screens the second heater more readily than the first heater.

主权项

1. A fixing device comprising:
a fixing rotator rotatable in a predetermined direction of rotation; a pressure rotator disposed opposite the fixing rotator; a nip formation pad pressing against the pressure rotator via the fixing rotator to form a fixing nip therebetween, through which a recording medium bearing a toner image is conveyed, the nip formation pad including:
a base having a basic thermal conductivity; anda first thermal conductor sandwiched between the base and the fixing rotator at the fixing nip and having a first thermal conductivity greater than the basic thermal conductivity of the base; a first heater disposed opposite an inner circumferential surface of the fixing rotator to heat the fixing rotator; a second heater disposed opposite the inner circumferential surface of the fixing rotator to heat the fixing rotator; a rotatable light shield to move to a shield position where the light shield is interposed between the second heater and the fixing rotator to shield the fixing rotator from light emitted from the second heater, the second heater being disposed at a location where the light shield screens the second heater more readily than the first heater; a flange to rotatably support the fixing rotator; a slider attached to the flange and including:
a slit extending in the direction of rotation of the fixing rotator; anda gear portion mounted on an outer circumferential surface of the slider; and a driver including a gear to mesh with the gear portion of the slider to drive and rotate the slider; wherein the light shield includes a projection projecting in an axial direction of the fixing rotator and being inserted into the slit of the slider.