Canon Kabushiki Kaisha

Hideto Iida

Takashige Kasuya

Shuhei Moribe

Koji Nishikawa

Tsutomu Onuma

Nobuyuki Okubo

Yoshihiro Ogawa

Hirohide Tanikawa

Katsuhisa Yamazaki

Hiroshi Yusa

A toner is composed of toner particles including toner base particles containing at least a binder resin and a colorant, and inorganic fine particles. The toner base particles having a specific circle-equivalent diameter as measured with a flow type particle image analyzer have a specific average circularity. The toner base particles have a specific surface roughness as measured with a scanning probe microscope. The binder resin contains at least a vinyl resin having as partial structure a linkage formed by the reaction of a carboxyl group with an epoxy group.

Toner

In a toner comprising toner particles which comprise toner base particles containing at least a binder resin and a magnetic material, and inorganic fine particles, the toner base particles have been obtained through a pulverization step; and, the toner base particles having a circle-equivalent diameter of from 3 &#x3bc;m or more to 400 &#x3bc;m or less as measured with a flow type particle image analyzer have an average circularity of from 0.935 or more to less than 0.970; and the toner base particles have an average surface roughness of from 5.0 nm or more to less than 35.0 nm as measured with a scanning probe microscope. The toner can enjoy less toner consumption per sheet of images, can achieve a long lifetime in a smaller quantity of toner, and has superior developing performance in any environment.

In a toner having a polyester resin as a binder resin component, and a colorant, the toner contains (a) in the binder resin component, from 20.0% by weight to 65.0% by weight of a tetrahydrofuran-insoluble matter A1 in 6-hour extraction and from 35.0% by weight to 80.0% by weight of a tetrahydrofuran-soluble matter A2 in 6-hour extraction, (b) in the binder resin component, from 10.0% by weight to 30.0% by weight of a tetrahydrofuran-insoluble matter B1 in 16-hour extraction and from 70.0% by weight to 90.0% by weight of a tetrahydrofuran-soluble matter B2 in 16-hour extraction, and (c) in the binder resin component, from 0.5% by weight to 3.0% by weight of an orthodichloro-benzene-insoluble matter C1 in 6-hour extraction at 185&#xb0; C. and from 97.0% by weight to 99.5% by weight of an orthodichlorobenzene-soluble matter C2 in 6-hour extraction at 185&#xb0; C. The proportion of C1 to B1, C1/B1, is from 0.06 to 0.15, and the A1, B1 and C1 satisfy the following expression (1):A1&#x3e;B1&#x3e;C1.&#x2003;&#x2003;Expression (1)A process cartridge makes use of this toner.

Toner, and process cartridge

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Chiba, Japan

Hideto Iida