Image Forming Apparatus

An image forming apparatus comprising:

• a photosensitive member;
• a scorotron charger which has a wire and a grid, and charges the photosensitive member;
• a developing device which supplies a developer to the photosensitive member;
• a voltage application circuit which applies a voltage to the scorotron charger;
• a constant-voltage circuit which sets a grid voltage of the grid to a constant voltage between the grid and an ground;
• a first control device which controls an output voltage of the voltage application circuit;
• a deboost circuit which deboosts the grid voltage between the grid and the ground to generate a developing voltage being applied to the developing device;
• and
• a second control device which controls an output of the deboost circuit,
• wherein
• the deboost circuit has a circuit configuration in which a resistor and a control transistor are connected in series with each other, and deboosts the grid voltage by a voltage drop of the resistor to generate the developing voltage, and
• the second control device provides a control signal to the control transistor to control a current flowing in the resistor, thereby controlling the level of the developing voltage.