Magnetic toner

US6638674B2 · kind B2 · utility

Assignee

• Canon Kabushiki Kaisha · JP

Inventors

• Keiji Komoto · Numazu, JP
• Tsuyoshi Takiguchi · Numazu, JP
• Tatsuhiko Chiba · Kamakura, JP
• Michihisa Magome · Mishima, JP
• Akira Hashimoto · Funabashi, JP
• Takeshi Kaburagi · Nanbu, JP
• Eriko Yanase · Mishima, JP

Key dates

• Filing date: Jul 25, 2001
• Grant date: Oct 28, 2003
• Expiry date: Jul 25, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G03G9/08726
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A magnetic toner is formed of magnetic toner particles each comprising a binder resin, an iron oxide, a sulfur-containing polymer, and inorganic fine powder blended with the magnetic toner particles, the toner having a weight-average particle size (D4) of 3-10 &mgr;m, and either (a) an average circularity of at least 0.970, and a magnetization of 10-50 Am2/kg (emu/g) at a magnetic field of 79.6 kA/m (1000 oersted), or (b) toner particles which retain carbon in an amount of A and iron in an amount of B at surfaces thereof, satisfying: B/A<0.001, and containing at least 50% by number of magnetic toner particles of D/C&lE;0.02, wherein C represents a particle projection area-equivalent circle diameter and D represents a minimum distance between a surface of the magnetic toner particle and iron oxide particles contained therein.