PRINTER AND METHOD OF CONTROLLING THE SAME

摘要

PURPOSE: A printer and a method of controlling the printer are provided to diagnose factors related developing conditions so as to optimize the developing conditions. CONSTITUTION: A printer includes a bias applying part(210) for applying a predetermined bias to a developing roller(131), an engine controller(230) for controlling the bias applying part, and a current detector(220) for detecting a current that flows through the developing roller in response to the bias applied by the bias applying part. The engine controller controls the bias applying part to apply the first test AC voltage to the developing roller at the first frequency and to apply the second test AC voltage to the developing roller at the second frequency. The engine controller calculates the resistance of the developing roller and a gap between the developing roller and a photosensitive drum using a current value detected by the current detector, and controls the bias applying part to apply a bias voltage corresponding to the calculated resistance and gap to the developing roller.