US 12,306,572 B2
Process cartridge
Shintaro Kawaguchi, Kanagawa (JP); Masamichi Sato, Shizuoka (JP); Masatake Tanaka, Kanagawa (JP); and Ryo Sugiyama, Shizuoka (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Sep. 13, 2021, as Appl. No. 17/473,819.
Claims priority of application No. 2020-162165 (JP), filed on Sep. 28, 2020.
Prior Publication US 2022/0100145 A1, Mar. 31, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G03G 15/08 (2006.01); G03G 9/08 (2006.01); G03G 9/097 (2006.01); G03G 21/18 (2006.01)
CPC G03G 21/1814 (2013.01) [G03G 9/0819 (2013.01); G03G 9/0825 (2013.01); G03G 9/09725 (2013.01); G03G 15/0812 (2013.01)] 6 Claims
OG exemplary drawing
 
1. A process cartridge attachable to and detachable from an electrophotographic apparatus main body, the process cartridge comprising:
a toner;
a developing roller; and
a regulating member,
wherein the developing roller comprises:
a conductive substrate,
an elastic layer on the conductive substrate, and
a surface layer on the elastic layer,
the surface layer comprises:
a binder resin,
a first resin particle, and
a second resin particle,
the surface layer has an outer surface having:
a first protruded portion, and
a second protruded portion that is present in a region not including the first protruded portion and that has a height 5.0 μm or more smaller than the height of the first protruded portion,
the first protruded portion is derived from the first resin particle,
the second protruded portion is derived from the second resin particle,
the first resin particle has an elastic coefficient of 100 MPa or more and 10,000 MPa or less, the elastic coefficient of the first resin particle being measured at the cross section of the surface layer in the thickness direction,
the second resin particle has an elastic coefficient of 2 MPa or more and 50 MPa or less, the elastic coefficient of the second resin particle being measured at the cross section of the surface layer in the thickness direction,
the outer surface has an average value of the maximum height Rz of 6 μm or more and 18 μm or less,
the toner comprises:
a toner particle, and
an external additive A dispersed on a surface of the toner particle and covering the surface of the toner particle,
the external additive A is a silica particle having a major diameter of 40 nm or more and 400 nm or less,
a surface coverage of the toner particle by the external additive A is 3.0% or more, and
a dispersion degree evaluation index D of the external additive A is 2.0 or less.