US 12,147,170 B2
Image forming apparatus having toner charging
Yuta Isobe, Meridian, ID (US); Kuniaki Tamagaki, Kanagawa (JP); Takashi Koyanagi, Shizuoka (JP); Akihisa Matsukawa, Tokyo (JP); Ryosuke Kanai, Kanagawa (JP); Hiroki Tanaka, Kanagawa (JP); Motonari Ito, Shizuoka (JP); Kazuhisa Shida, Kanagawa (JP); and Makoto Fukatsu, Shizuoka (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Appl. No. 17/437,987
Filed by Canon Kabushiki Kaisha, Tokyo (JP)
PCT Filed Mar. 11, 2020, PCT No. PCT/JP2020/010425
§ 371(c)(1), (2) Date Sep. 10, 2021,
PCT Pub. No. WO2020/184595, PCT Pub. Date Sep. 17, 2020.
Claims priority of application No. 2019-044320 (JP), filed on Mar. 11, 2019; and application No. 2019-044321 (JP), filed on Mar. 11, 2019.
Prior Publication US 2022/0187734 A1, Jun. 16, 2022
Int. Cl. G03G 15/08 (2006.01); C08G 18/78 (2006.01); G03G 15/00 (2006.01); G03G 15/06 (2006.01); G03G 21/20 (2006.01)
CPC G03G 15/065 (2013.01) [C08G 18/785 (2013.01); G03G 15/0808 (2013.01); G03G 15/0812 (2013.01); G03G 15/0817 (2013.01); G03G 15/0818 (2013.01); G03G 15/5004 (2013.01); G03G 21/203 (2013.01)] 64 Claims
OG exemplary drawing
 
1. An image forming apparatus comprising:
an image bearing member that forms an electrostatic latent image;
a developer container that stores a developer;
a developer carrying member that bears and conveys the developer;
a regulating member that makes contact with the developer carrying member to regulate a layer thickness of the developer borne by the developer carrying member;
an interval maintaining member that maintains a distance between the image bearing member and the developer carrying member;
a power source that applies a voltage to the developer carrying member; and
a controller that controls the power source, wherein
the developer carrying member has at least a base and a surface layer,
the surface layer has an electron donating portion that mainly donates charge to the developer when the developer and the surface layer make frictional contact to exchange charge and an electron accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge,
the controller applies an AC voltage to the developer carrying member during a period in which an image forming operation is not performed and the developer carrying member is driven, the AC voltage being different from that applied during an image forming period, and
a rotating speed of the developer carrying member during a non-image forming period is slower than that during an image forming period.