US 12,276,926 B2
Development device, image forming apparatus, and development method
Takeshi Arakawa, Osaka (JP)
Assigned to KYOCERA Document Solutions Inc., Osaka (JP)
Filed by KYOCERA Document Solutions Inc., Osaka (JP)
Filed on Oct. 30, 2023, as Appl. No. 18/497,980.
Claims priority of application No. 2022-174765 (JP), filed on Oct. 31, 2022.
Prior Publication US 2024/0142897 A1, May 2, 2024
Int. Cl. G03G 15/09 (2006.01); G03G 9/08 (2006.01); G03G 9/107 (2006.01)
CPC G03G 15/0921 (2013.01) [G03G 9/0815 (2013.01); G03G 9/1087 (2020.08)] 8 Claims
OG exemplary drawing
 
1. A development device comprising:
an accommodation section that accommodates a developer; and
a developer bearing member that carries the developer in the accommodation section, wherein
the developer bearing member includes a magnetic member and a sleeve provided around the magnetic member rotatably around the magnetic member,
the sleeve includes a metal substrate with a surface having projections and recesses and a plating layer covering the surface of the metal substrate,
the plating layer contains chromium and cobalt,
the developer contains a toner and the toner includes toner particles,
the toner particles each include a toner mother particle and external additive particles attached to a surface of the toner mother particle,
the toner mother particles contain a binder resin and a magnetic powder,
the external additive particles include alumina particles with surfaces that are hydrophobized, and
a number-average primary particle diameter of the alumina particles is more than 0.1 μm.