Image forming apparatus controlling charging voltages

An image forming apparatus comprising:

• a rotatable photosensitive member;
• a first charging member configured to electrically charge a surface of the photosensitive member in contact with the surface of the photosensitive member in a first charging position with respect to a rotational direction of the photosensitive member;
• a second charging member configured to electrically charge the surface of the photosensitive member in a second charging position with respect to the rotational direction of the photosensitive member;
• a developing member configured to form a toner image on the surface of the photosensitive member by supplying toner, charged to a predetermined polarity, to the surface of the photosensitive member in a developing position with respect to the rotational direction of the photosensitive member;
• a transfer member contacting the surface of the photosensitive member in a transfer position with respect to the rotational direction of the photosensitive member and configured to transfer the toner image from the photosensitive member onto a recording material passing through between the photosensitive member and the transfer member;
• a first charging voltage applying portion configured to apply a first charging voltage of the predetermined polarity to the first charging member;
• a second charging voltage applying portion configured to apply a second charging voltage of the predetermined polarity to the second charging member;
• a transfer voltage applying portion configured to apply a transfer voltage, of an opposite polarity to the predetermined polarity, to the transfer member;
• and
• a controller configured to control the first charging voltage applying portion, the second charging voltage applying portion, and the transfer voltage applying portion,
• wherein with respect to the rotational direction of the photosensitive member,
• the first charging position is positioned downstream of the transfer position and upstream of the second charging position,
• the second charging position is positioned downstream of the first charging position and upstream of the developing position,
• the developing position is positioned downstream of the second charging position and upstream of the transfer position, and
• the transfer position is positioned downstream of the developing position and upstream of the first charging position, and
• wherein the controller controls:
• the transfer voltage applying portion so that on the surface of the photosensitive member directly contacting the transfer member in the transfer position, a region corresponding to between the recording material and a subsequent recording material, which is a recording material subsequent to the recording material, has a potential of the opposite polarity to the predetermined polarity,
• the first charging voltage applying portion so that the surface of the photosensitive member is charged in the first charging position by applying the first charging voltage of less than a discharge start voltage to the first charging member in the first charging position,
• the second charging voltage applying portion so that the surface of the photosensitive member is charged in the second charging position by applying the second charging voltage of not less than the discharge start voltage to the second charging member in the second charging position, and
• the first charging voltage applying portion so that a first charging ratio is 10% or more, wherein with respect to the region corresponding to between the recording material and the subsequent recording material, when a ratio of a surface potential of the photosensitive member changed in the first charging position to a surface potential of the photosensitive member changed in the first charging position and the second charging position is the first charging ratio.