US 12,124,183 B2
Image forming apparatus capable of suppressing an improper charge resulting from toner being moved from a transfer member to a photosensitive member
Shinsuke Kobayashi, Kanagawa (JP); Kensuke Umeda, Kanagawa (JP); Ai Suzuki, Tokyo (JP); Kazuhiro Funatani, Kanagawa (JP); Shuichi Tetsuno, Kanagawa (JP); Toshihiko Takayama, Kanagawa (JP); and Jun Hara, Kanagawa (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Jun. 15, 2023, as Appl. No. 18/335,237.
Application 18/335,237 is a division of application No. 17/515,636, filed on Nov. 1, 2021, granted, now 11,703,775.
Claims priority of application No. 2020-210846 (JP), filed on Dec. 18, 2020.
Prior Publication US 2023/0324825 A1, Oct. 12, 2023
Int. Cl. G03G 15/02 (2006.01); G03G 15/06 (2006.01); G03G 15/16 (2006.01); G03G 21/00 (2006.01)
CPC G03G 15/0266 (2013.01) [G03G 15/0225 (2013.01); G03G 15/065 (2013.01); G03G 15/1675 (2013.01); G03G 21/0064 (2013.01)] 12 Claims
OG exemplary drawing
 
1. An image forming apparatus comprising:
a rotatable photosensitive member;
a charging member forming a charging portion in contact with the photosensitive member and configured to electrically charge a surface of the photosensitive member at the charging portion;
an electrostatic image forming portion configured to form an electrostatic image on the photosensitive member charged by the charging member;
a developing device configured to form a toner image on the photosensitive member by supplying toner, charged to a normal polarity, to the electrostatic image;
a transfer member forming a transfer portion in contact with the photosensitive member and configured to transfer the toner image from the photosensitive member onto a recording material passing through the transfer portion;
a brush member forming a contact portion in contact with the photosensitive member on a side downstream of the transfer portion and an upstream side of the charging portion with respect to a rotational direction of the photosensitive member;
a brush voltage source configured to apply a voltage to the brush member; and
a controller capable of executing a cleaning operation for moving the toner, deposited on the transfer member, from the transfer member onto the surface of the photosensitive member when the recording material is absent at the transfer portion,
wherein the controller carries out control so that the cleaning operation includes:
(1) a first operation in which a potential difference is formed between the brush member and the photosensitive member so that electrostatic force acts such that the toner charged to an opposite polarity to the normal charge polarity is moved from the brush member toward the photosensitive member,
(2) a second operation in which a potential difference is formed between the brush member and the photosensitive member so that the electrostatic force acts such that the toner charged to the normal charge polarity is moved from the brush member toward the photosensitive member,
(3) a third operation in which a potential difference is formed between the charging member and the photosensitive member so that the electrostatic force acts such that the toner charged to the normal charge polarity is moved from the charging member toward the photosensitive member, and
(4) a fourth operation in which a potential difference is formed between the developing member and the photosensitive member so that the electrostatic force acts such that the toner charged to the normal charge polarity is moved from the photosensitive member toward the developing member.