Image forming apparatus

An image forming apparatus for performing image forming operation to form an image on a transfer-receiving member, the image forming apparatus comprising:

• a rotatable photosensitive member;
• a charging member configured to charge a surface of the rotatable photosensitive member at a charging portion where the charging member faces the rotatable photosensitive member;
• an exposure unit configured to expose the surface of the rotatable photosensitive member charged by the charging member, to form an electrostatic latent image on the surface of the rotatable photosensitive member;
• a developing member configured to develop the electrostatic latent image as a developer image by supplying a developer charged to normal polarity to the surface of the rotatable photosensitive member;
• a transfer member configured to form a transfer portion by coming into contact with the rotatable photosensitive member, and to transfer the developer image from the rotatable photosensitive member to the transfer-receiving member at the transfer portion;
• a brush configured to form a contact portion on a downstream side of the transfer portion and on an upstream side of the charging portion in a rotation direction of the rotatable photosensitive member, and to come into contact with the rotatable photosensitive member at the contact portion;
• a voltage application unit configured to apply a voltage to the brush;
• a driving unit configured to rotationally drive the rotatable photosensitive member;
• and
• a control unit configured to control the voltage application unit and the driving unit,
• wherein, after the developer image formed on the surface of the rotatable photosensitive member is transferred to the transfer-receiving member at the transfer portion, developer remaining on the surface of the rotatable photosensitive member is collected by the developing member,
• wherein the control unit is configured to perform control of the image forming operation and a non-image forming operation which is different from the image forming operation,
• wherein, in a case of performing control, the control unit performs control to the voltage application unit such that a polarity of a first voltage applied to the brush when a first region of the rotatable photosensitive member forming the transfer portion passes through the contact portion during the image forming operation is different from a polarity of a second voltage applied to the brush when a second region of the rotatable photosensitive member forming the transfer portion passes through the contact portion while operation is shifted from a first operation in which the rotatable photosensitive member is rotated at a first speed to a second operation in which the rotatable photosensitive member is rotated at a second speed different from the first speed during the non-image forming operation, and
• wherein, relative to a posture of the brush during the second operation, the brush takes a posture during the first operation of falling toward downstream in the rotation direction of the rotatable photosensitive member.