US 11,703,775 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 Nov. 1, 2021, as Appl. No. 17/515,636.
Claims priority of application No. 2020-210846 (JP), filed on Dec. 18, 2020.
Prior Publication US 2022/0197175 A1, Jun. 23, 2022
Int. Cl. G03G 15/16 (2006.01); G03G 15/02 (2006.01); G03G 15/06 (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)] 19 Claims
OG exemplary drawing
 
1. An image forming apparatus comprising:
a rotatable photosensitive member;
a charging member forming a charging portion in contact with said photosensitive member and configured to electrically charge a surface of said photosensitive member at said charging portion;
an electrostatic image forming portion configured to form an electrostatic image on said photosensitive member charged by said charging member;
a developing device configured to form a toner image on said photosensitive member by supplying toner, charged to a normal polarity, to the electrostatic image;
a transfer member forming a transfer portion in contact with said photosensitive member and configured to transfer the toner image from said photosensitive member onto a recording material passing through said transfer portion;
a transfer voltage source configured to apply a voltage to said transfer member;
a brush member forming a contact portion in contact with said photosensitive member on a side downstream of said transfer portion and an upstream side of said charging portion with respect to a rotational direction of said photosensitive member;
a brush voltage source configured to apply a voltage to said brush member; and
a controller capable of executing a cleaning operation for moving the toner, deposited on said transfer member, from said transfer member onto the surface of said photosensitive member when the recording material is absent at said transfer portion,
wherein said controller carries out control so that the cleaning operation includes:
a first operation in which a potential difference is formed between said transfer member and said photosensitive member so that the toner charged to the normal charge polarity is moved from said transfer member toward said photosensitive member, and
a second operation in which a potential difference is formed between said brush member and said photosensitive member so that the toner charged to an opposite polarity to the normal charge polarity is moved from said brush member toward said photosensitive member.