Patent ID: 8594521

Claim:
An image forming apparatus comprising: a plurality of photosensitive drums; a plurality of scorotron chargers provided for the plurality of photosensitive drums, respectively, the plurality of scorotron chargers configured to charge the photosensitive drums, respectively; a voltage application circuit commonly connected to the plurality of scorotron chargers, the voltage application circuit configured to apply voltages to the plurality of scorotron chargers; a plurality of wires provided for the plurality of scorotron chargers, respectively; a plurality of grid electrodes provided for the plurality of scorotron chargers, respectively; a plurality of current detecting units provided for the plurality of grid electrodes, respectively, the current detecting units configured to detect grid current flowing into the grid electrodes, respectively; and a control device configured to: determine a minimum current value from the detected grid currents, and control the voltage application circuit such that a grid current of the minimum current value becomes a constant current equal to or higher than a reference value.