Zeon Corporation

Kanto Denka Kogyo Co., Ltd.

Kenichi Yamazaki

Takeru Chiba

Hidehiko Iinuma

Hiromichi Jin

An electrostatic image developer having little change in charge amount, no generation of fog and excellent environmental stability under all of low temperature and low humidity environment, normal temperature and normal humidity environment, and high temperature and high humidity environment is provided. Disclosed is an electrostatic image developer comprising a colored resin particle containing a binder resin and a colorant, and an external additive, wherein the external additive contains an alumina fine particle in plate-like shape subjected to a hydrophobicity-imparting treatment having a number average primary particle diameter of 20 to 120 nm and an aspect ratio of 3 to 15, and a content of the alumina fine particle is in the range from 0.05 to 1 part by mass with respect to 100 parts by mass of the colored resin particle.

Growing community of inventors

Gunma, Japan

Kenichi Yamazaki