Patent Number: 6,165,663

Title: Magnetic coated carrier two-component type developer and developing method

Abstract: A magnetic coated carrier suitable for constituting a two-component type developer for use in electrophotography is composed of magnetic coated carrier particles comprising magnetic coated carrier particles comprising magnetic carrier core particles each comprising a binder resin and metal oxide particles, and a coating layer surface-coating each carrier core particle. The metal oxide particles have been subjected to a surface lipophilicity-imparting treatment. The magnetic carrier core particles have a resistivity of at least 1.times.10.sup.10 ohm.cm, and the magnetic coated carrier has a resistivity of at least 1.times.10.sup.12 ohm.cm. The magnetic coated carrier has a particle size distribution such that (i) it has a number-average particle size Dn of 5-100 .mu.m, (ii) it satisfies a relationship of Dn/.sigma..gtoreq.3.5, wherein .sigma. denotes a standard deviation of number-basis particle size distribution of the carrier, and (iii) it contains at most 25% by number of particles having particle sizes of at most Dn.times.2/3.

Inventors: Baba; Yoshinobu (Yokohama, JP), Ikeda; Takeshi (Shizuoka-ken, JP), Sato; Yuko (Numazu, JP), Itabashi; Hitoshi (Yokohama, JP), Tokunaga; Yuzo (Yokohama, JP)

Assignee: Canon Kabushiki Kaisha

International Classification: G03G 9/113 (20060101); G03G 9/08 (20060101); G03G 9/10 (20060101); G03G 9/107 (20060101); G03G 009/107 (); G03G 013/09 ()

Expiration Date: 12/26/2017