Image forming apparatus

An image forming apparatus comprising:

• a photosensitive drum configured to be rotatable;
• a charging roller configured to come into contact with the photosensitive drum to form a charging portion and charge a surface of the photosensitive drum at the charging portion;
• a development roller configured to be rotatable and to come into contact with the photosensitive drum to form a development portion and develop a toner image at the development portion by supplying a toner charged to a normal polarity as a negative polarity to the surface of the photosensitive drum;
• a transfer roller configured to form a transfer portion opposed to the photosensitive drum and transfer the toner image from the photosensitive drum to a transfer material at the transfer portion;
• a charging voltage power source configured to apply a charging voltage to the charging roller;
• a development voltage power source configured to apply a development voltage to the development roller;
• and
• a controller configured to control the charging voltage power source and the development voltage power source,
• wherein the development roller collects the toner that remains on the surface of the photosensitive drum after the toner image formed on the surface of the photosensitive drum at the transfer portion is transferred from the transfer portion to the transfer material,
• wherein the controller controls to perform an image forming operation of forming the toner image on the transfer material and a cleaning operation of cleaning a surface of the charging roller in a state where the photosensitive drum, the charging roller, and the development roller are rotated, and
• wherein the controller controls application of the development voltage to apply, to the development roller in the cleaning operation, a development voltage having a positive polarity, and controls application of the charging voltage to apply, to the charging roller, a charging voltage having the negative polarity such that a potential difference formed at the charging portion between the applied charging voltage and a surface potential formed at the surface of the photosensitive drum is lower than or equal to a discharge start voltage and the potential difference is in a direction in which electrostatic force directed from the charging roller to the photosensitive drum acts on the toner charged to the negative polarity.