Patent ID: 7430381

Claim:
A developing device, comprising: a developing tank configured to contain two-component developer including toner and carrier and to stir the two-component developer at a plurality of stirring velocities; a toner density sensor configured to detect toner density in the developing tank; a toner supply section configured to supply toner to the developing tank; and a control section configured to input, to the toner density sensor, a control voltage for correcting a sensor output that is outputted from the toner density sensor, wherein the control section is configured to set a standard control voltage for correcting a sensor output obtained by sensing density of two-component developer having standard toner density having been set to a certain value so that the sensor output corresponds to each of the stirring velocities, and the control section is configured to set the control voltage by use of the standard control voltage so that the sensor output has a value within a range indicative of predetermined toner density so as to correspond to each of the stirring velocities.