Patent Number: 7,709,171

Title: Charge control agent, toner and toner producing method

Abstract: The present invention provides a charge control agent, adapted to control charging ability of resins or compositions containing resins, comprising a copolymer that comprises a polymer block A and a polymer block B, the polymer block A is prepared by copolymerizing a maleimide, which being unsubstituted or substituted for a hydrogen atom of an imide group by an electron-donating group, and styrene or a styrene derivative, and the polymer block B is formed of a polymer of styrene or a styrene derivative.

Inventors: Yamamoto; Atsushi (Kawanishi, JP), Nozaki; Chiyoshi (Otsu, JP), Nozaki; Tsuyoshi (Ikeda, JP), Matsumoto; Mitsuyo (Ibaraki, JP), Kurose; Katsunori (Takarazuka, JP)

Assignee: Ricoh Company, Ltd.

International Classification: G03G 9/097 (20060101)

Expiration Date: 5/04/12018