Canon Kabushiki Kaisha

Masami Azuma

Takashige Kasuya

Yusuke Hasegawa

Katsuhisa Yamazaki

Tadashi Dojo

Takeshi Naka

Nene Shibayama

Tsuneo Nakanishi

Yuichi Mizoo

Satoshi Matsunaga

A toner contains at least a bonding resin and a coloring agent, and has a weight mean particle size from 5 &mgr;m to 12 &mgr;m; not less than 90% by number of particles not less than 3 &mgr;m have a circularity &ldquo;a&rdquo; not less than 0.900; a cut ratio Z and a weight mean size X of the toner are related as: cut ratio Z&lE;5.3&times;X; and a relationship of particles Y having a circularity of not less than 0.950 and a weight mean size X is Y&gE;e &times;X where X is 5 to 12 &mgr;m.

Toner, process for producing toner image forming method and apparatus unit

A toner manufacturing method includes grinding and classification to produce a toner containing a binder resin and a colorant with a weight mean particle size of 5 microns to 12 microns and sharp particle density distribution. The toner has a specific circularity, relationship between cut ratio and weight mean size, and relationship between circularity and weight mean size as disclosed in the specification.

A toner has toner particles containing at least a binder resin, a colorant and a sulfur-containing compound selected from the group consisting of a sulfur-containing polymer and a sulfur-containing copolymer. The toner has a weight-average particle diameter of from 5 &mgr;m to 12 &mgr;m, and the toner has, in its particles of 3 &mgr;m or larger in diameter, at least 90% by number of particles with a circularity of 0.900 or higher, and has a specific relationship between the cut rate Z and the toner weight-average particle diameter X and a specific relationship between the number-based cumulative value Y of particles with a circularity of 0.950 or higher and the toner weight-average particle diameter X. Also disclosed are an image-forming method and a process cartridge which make use of the toner.

Toner, image-forming method and process cartridge

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Toride, Japan

Masami Azuma