Two-component developer, container filled with the two-component developer, and image formation apparatus

US6468706B2 · kind B2 · utility

Assignee

• RICOH COMPANY, LTD. · JP

Inventors

• Hiroaki Matsuda · Osaka, JP
• Masanori Suzuki · Hanamaki, JP
• Akemi Sugiyama · Numazu, JP
• Hiroto Higuchi · Numazu, JP
• Tsunemi Sugiyama · Kashiwa, JP
• Fumihiro Sasaki · Nanbu, JP
• Yasuaki Iwamoto · Numazu, JP
• Hiroshi Nakai · Hamamatsu, JP
• Kumi Hasegawa · Numazu, JP

Key dates

• Filing date: May 23, 2001
• Grant date: Oct 22, 2002
• Expiry date: May 23, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G03G9/1085
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A two-component developer consists of a toner, which contains at least a resin and a colorant and to which an external additive is added, and a carrier. This two-component developer has the toner that has a number average molecular weight (Mn) of 3,000 or less and contains particles having a molecular weight of 1,000 or less at 40 number % or more, and also has the carrier that satisfies general formula (1) as follows:3,000,000≦&sgr;1000×Dc3≦20,000,000  (1) where &sgr;1000 represents a magnetization (emu/g) of a carrier at 1,000 oersted, and Dc represents volume average particle diameter (&mgr;m) of the carrier.