Sensor apparatus and image forming apparatus

Abstract

A sensor apparatus outputs an output signal corresponding to a density of a toner image in an image forming apparatus. The sensor apparatus includes a light emitting element, a light receiving element, and an impedance element. The light emitting element irradiates light onto an image carrier that carries the toner image. The light receiving element receives light reflected off the image carrier. The impedance element changes an impedance of the impedance element according to a temperature of the impedance element. The output signal is a signal of which a magnitude is changed according to an amount of light received by the light receiving element. The impedance element is connected to the light emitting element or the light receiving element such that a change in the magnitude of the output signal that is caused due to a change in a temperature of the light emitting element is reduced.

Dependencies are inferred from the claim text.