Canon Kabushiki Kaisha

Nene Dojo

Masayoshi Shimamura

Satoshi Otake

Minoru Ito

Kazunori Saiki

Tatsuya Nakamura

Michihisa Magome

Yasutaka Akashi

Tomohisa Sano

Yasuhide Goseki

Tadashi Dojo

Eriko Yanase

Yusutaka Akashi

To provide a magnetic toner which: enables a stable image density to be obtained irrespective of a use environment; and exhibits excellent low-temperature fixability, little image deterioration upon fixation, high coloring power, and a reduced toner consumption. The present invention relates to a magnetic toner containing at least: a binder resin; and a magnetic body. The binder resin contains a polyester unit. The toner has a weight average particle size of 5.0 to 9.0 &#x3bc;m, a true specific gravity of 1.3 to 1.7 g/cm, and a saturated magnetization of 20 to 35 Am/kg in a magnetic field of 796 kA/m. The dielectric loss tangent (tan &#x3b4;) of the toner satisfies (tan &#x3b4;&#x2212;tan &#x3b4;)/tan &#x3b4;&#x2266;0.20 at 100 kHz.

Magnetic toner

A developer carrying member is provided which, even in continuous copying over a long term and also even under different environmental conditions, do not cause any charge-up of toner, and prevent the toner from melt-adherent to the developer carrying member surface and developer layer thickness control member surface to maintain the state of uniform coating of a developer having a toner and to make the toner uniformly and quickly triboelectrically charged, so as to obtain high-grade images free of any image density decrease, image density non-uniformity, sleeve ghosts, fog and vertical streaks during running service. Provided are a developer carrying member having a substrate and a resin coat layer on the surface of the substrate, which resin coat layer contains at least a binder resin and a carbon black, where the graphite (002) plane obtained from X-ray diffraction of the carbon black has a lattice spacing of from 0.3370 nm or more to 0.3450 nm or less; and a developing assembly having such a developer carrying member.

Developer carrying member and developing assembly

A developing method is provided in which a developer is carried on a developer carrying member, a thin layer of the developer is formed thereon and a latent image on a latent image bearing member is developed with a developer. The developer is composed of magnetic toner particles containing a binder resin and a magnetic powder. The magnetic powder has a saturation magnetization of 67.0 Am/kg to 75.0 Am/kg in a magnetic field of 79.6 kA/m (1,000 oersteds) and has a residual magnetization of 4.5 Am/kg or less. In the surface profile of the conductive resin coat layer of the developer carrying member, the relationship 1.00&#x2266;S/A&#x2266;1.65 is satisfied where S is a surface area of regions zoned by an area A of microscopic unevenness regions from which parts exceeding a reference plane by 0.5&#xd7;r (r: weight average particle diameter (&#x3bc;m) of a toner used) or more have been excluded.

Developing method and developing assembly

Growing community of inventors

Numazu, Japan

Nene Dojo