US 11,747,753 B2
Image forming apparatus configured to control the voltage applied to the transfer member to suppress image defects
Shinsuke Kobayashi, Yokohama (JP); Kazuhiro Funatani, Kawasaki (JP); Kensuke Umeda, Kawasaki (JP); Takanori Watanabe, Kawasaki (JP); and Ai Suzuki, Tokyo (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Jan. 3, 2022, as Appl. No. 17/567,456.
Application 17/567,456 is a continuation of application No. 17/005,160, filed on Aug. 27, 2020, granted, now 11,243,485.
Claims priority of application No. 2019-157415 (JP), filed on Aug. 29, 2019.
Prior Publication US 2022/0121140 A1, Apr. 21, 2022
Int. Cl. G03G 15/16 (2006.01); G03G 15/00 (2006.01)
CPC G03G 15/1675 (2013.01) [G03G 15/80 (2013.01)] 12 Claims
OG exemplary drawing
 
1. An image forming apparatus, comprising:
a photosensitive member which is rotatable;
a charging member configured to charge a surface of the photosensitive member and disposed at a charging position with respect to a rotation direction of the photosensitive member;
a developing device including
a developing member, which is rotatable, disposed opposite to the photosensitive member at a developing position with respect to the rotation direction of the photosensitive member and configured to bear toner,
wherein the developing device is configured to supply the toner on the developing member to an electrostatic image on the photosensitive member to form a toner image on the photosensitive member at the developing position;
a transfer member which is urged toward the photosensitive member at a transfer position with respect to the rotation direction of the photosensitive member;
a developing power source configured to apply a developing voltage to the developing member;
a transfer power source configured to apply a transfer voltage to the transfer member; and
a control unit configured to control the developing power source and the transfer power source,
wherein, when the photosensitive member transitions from a first state in which the photosensitive member is stopped to a second state in which the photosensitive member rotates, the surface of the photosensitive member is in contact with a surface of the developing member at the developing position and the surface of the photosensitive member is in contact with a surface of the transfer member at the transfer position,
wherein, at a start time of a start-up operation at a time of starting an image forming operation, on the surface of the photosensitive member, a first position coincides with the charging position, a second position coincides with the developing position, and a third position coincides with the transfer position,
wherein the developing device is configured to collect the toner on the photosensitive member having passed the third position, and
wherein, in a state where the developing voltage having a polarity opposite to a normal charging polarity of the toner is applied to the developing member by the developing power source, during a period in which an area on the photosensitive member located downstream of the first position and upstream of the third position with respect to the rotation direction of the photosensitive member passes the third position, the control unit performs control of applying a first voltage having a same polarity as the normal charging polarity of the toner to the transfer member by the transfer power source.