Canon Kabushiki Kaisha

Chika Inoue

Hiroyuki Fujikawa

Yoshinobu Baba

Takayuki Itakura

Kunihiko Nakamura

Nozomu Komatsu

Koh Ishigami

Tomoko Endo

A magnetic carrier is provided which uses a toner having high coloring power and enables development to be performed at low electric field intensity and can form high quality images while keeping gradation characteristics. The magnetic carrier includes magnetic carrier particles including at least porous magnetic core particles and a resin. The electric field intensity just before the break-down of the magnetic carrier is 1,300 V/cm or more and 5,000 V/cm or less.

Magnetic carrier, two-component developer and image forming method

A magnetic carrier and a two-component developer are provided which have remedied blank areas, fog after leaving, carrier sticking during running, and image density variations before and after running. The magnetic carrier has magnetic carrier particles having at least porous magnetic core particles and a resin. The magnetic carrier particles satisfying the specific conditions (a), (b) and (c) where, in a reflected electron image of cross sections of the magnetic carrier particles as photographed with a scanning electron microscope, straight lines that divide a cross section of a magnetic carrier particle into 72 at intervals of 5&#xb0; are drawn from a reference point of the cross section thereof toward the surface of the magnetic carrier particle; the magnetic carrier particles being contained in an amount of 60% by number or more.

Magnetic carrier and two-component developer

Provided is a magnetic carrier giving a high quality image free of density variation without the occurrence of fogging or carrier adhesion and having excellent dot reproducibility even during long-term use. The magnetic carrier has magnetic carrier particles produced by filling pores of porous magnetic core particles with a resin. The magnetic carrier contains 80% by number or more of the magnetic carrier particles satisfying the specific conditions (a) and (b) when 18 straight lines passing through a reference point of a cross section of the magnetic carrier particle are drawn at intervals of 10&#xb0; in a reflected electron image of the cross section of the magnetic carrier particle photographed by a scanning electron microscope.

Magnetic carrier and two component developer

A magnetic carrier which has magnetic carrier particles each having at least porous magnetic core particles and a resin, in which, in a backscattered electron image of the magnetic carrier particles, photographed with a scanning electron microscope as taken at an accelerating voltage of 2.0 kV, magnetic carrier particles having area proportion Sfound from a specific expression (1) of from 0.5 area % or more to 8.0 area % or less are in a proportion of 8.0% by number or more in the magnetic carrier, an average proportion Avof the total area of portions having a high luminance which come from a metal oxide on the magnetic carrier particles to the total projected area of the magnetic carrier particles is from 0.5 area % or more to 8.0 area % or less, and an average proportion Avfound from a specific expression (2) is 10.0 area % or less.

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Berlin, Germany

Chika Inoue