US 12,124,214 B2
Electrostatic charge image developer, process cartridge, image forming apparatus, and image forming method
Yasuo Kadokura, Minamiashigara (JP); Takuro Watanabe, Minamiashigara (JP); Karin Sakai, Minamiashigara (JP); Kazutsuna Sasaki, Minamiashigara (JP); and Yosuke Tsurumi, Minamiashigara (JP)
Assigned to FUJIFILM Business Innovation Corp., Tokyo (JP)
Filed by FUJIFILM Business Innovation Corp., Tokyo (JP)
Filed on Aug. 17, 2021, as Appl. No. 17/404,623.
Claims priority of application No. 2021-085621 (JP), filed on May 20, 2021.
Prior Publication US 2022/0373923 A1, Nov. 24, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G03G 15/08 (2006.01); G03G 9/08 (2006.01); G03G 9/113 (2006.01); G03G 21/18 (2006.01)
CPC G03G 9/1139 (2013.01) [G03G 9/0819 (2013.01); G03G 9/0821 (2013.01); G03G 15/08 (2013.01); G03G 21/1814 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An electrostatic charge image developer comprising:
a toner containing a toner particle and an external additive; and
a carrier containing a magnetic particle and a resin layer covering the magnetic particle, wherein
the toner particle has a surface property index value of 2.0 or more and 2.8 or less,
the carrier has a surface having a ratio B/A of a surface area B to a planar view area A of 1.020 or more and 1.100 or less, the planar view area A and the surface area B being obtained by three-dimensional analysis of the surface of the carrier,
the resin layer contains inorganic particles having an average particle diameter of 4 nm or more and 93 nm or less,
a content of the inorganic particles contained in the resin layer is 10 mass % or more and 60 mass % or less, and
average thickness of the resin layer is 0.5 μm or more and 1.5 μm or less.