Image forming apparatus

An image forming apparatus comprising:

• a photosensitive drum;
• a charging member configured to electrically charge a surface of the photosensitive drum at a charging portion;
• an exposing unit configured to expose a surface of the photosensitive drum to light to form an electrostatic latent image on the surface of the photosensitive drum electrically charged by the charging member;
• a developing member configured to develop the electrostatic latent image formed on the surface of the photosensitive drum with a developer and to form a developer image at a developing portion;
• a transfer member configured to transfer the developer image formed by the developing member to a recording material at a transfer portion;
• a contacting member provided upstream of the charging portion and downstream of the transfer position with respect to a rotational direction of the photosensitive drum and contacting the surface of the photosensitive drum at a contacting portion;
• a first applying portion configured to apply a charging voltage to the charging member;
• a second applying portion configured to apply a developing voltage to the developing member;
• and
• a controller configured to control the first applying portion and the second applying portion to perform (1) an image formation operation for forming an image on the recording material and (2) a non-image formation operation which is different from the image formation operation and which does not form the image on the recording material, and to collect the toner remaining on the photosensitive drum without being transferred to the recording material by the transfer member,
• wherein when an area of the photosensitive drum in the developing portion is defined as a first area and an area of the photosensitive drum in the charging portion is defined as a second area, the controller controls so as to execute following operations in the non-image formation operation,
• i) a first operation in which the controller controls the second applying portion so as to form a first potential difference, between the photosensitive drum and the developing member, by which the toner charged with a normal polarity is moved from the photosensitive drum to the developing member in the first area in a state in which a surface potential of the photosensitive drum formed between the charging portion and the developing portion in a rotational direction of the photosensitive drum is smaller in an absolute value than the surface potential of the photosensitive drum charged in the charging portion in the image formation operation, and
• ii) a second operation in which after executing the first operation, when the second area is charged by applying the charging voltage to the charging member by the first applying portion and the second area is moved to the developing portion by rotation of the photosensitive drum, the controller controls the first applying portion and the second applying portion so as to form a second potential difference, between the photosensitive drum and the developing member, by which the toner charged with the normal polarity in the developing portion is moved from the photosensitive drum to the developing member, and before the second area passing through the developing portion reaches the contacting area, to form a third potential difference, between the photosensitive drum and the contacting member, by which the toner charged with the normal polarity in the contacting portion is moved from the contacting member to the photosensitive drum.