Patent ID: 8577236

Claim:
A developing station of an image forming apparatus, the developing station comprising: a sensor configured to detect a property of a developer material residing in a housing; a transport unit within the housing that is operatively in contact with the developer material residing in the housing, the transport unit being configured to move the developer material residing in the housing toward a recording medium outside the housing; a power supply configured to apply a voltage to the transport unit; and a controller configured to receive the property of the developer material residing in the housing detected by the sensor and further configured to change, based upon the property of the developer material detected by the sensor, the voltage applied to the transport unit by the power supply, wherein: the property of the developer material residing in the housing is toner age calculated as a mean residence time that toner resides in the housing, an alternating current potential may be set at a maximum potential when the toner age is less than a high threshold and the alternating current potential may be set at a nominal potential when the toner age is greater than a low threshold, and when toner age is between the high and the low thresholds, the controller can linearly decrease the alternating current potential as the toner age increases.