Ricoh Company, Ltd.

Yuta Takeuchi

Tsuyoshi Nozaki

Yoshimichi Ishikawa

Tomoharu Miki

Yoshihiro Mikuriya

Takuya Kadota

Takayuki Nakamura

Kazuoki Fuwa

Tomohiro Fukao

Hideaki Yasunaga

Naoki Nakatake

Keiichiro Juri

Yasuhide Matsuno

Tsuyoshi Nokaki

A toner is provided. The toner includes toner particles each including a binder resin and a release agent. From 20% to 80% by number of the toner particles satisfy the following formula (1) and (2):2/3&#x2264;&#x2264;1.5&#x2003;&#x2003;(1)1/3&#x2264;&#x2264;1.0&#x2003;&#x2003;(2)wherein Dv represents a volume average particle diameter of the toner particles; and T and R represent the longest cross-sectional diameters of each toner particle and the release agent contained therein, respectively, measured by observing cross-sections of the toner particles with scanning transmission electron microscope.

Toner, developing device, and process cartridge

A toner is provided. The toner includes a crystalline resin and a non-crystalline resin, and has a thermal property such that when the toner is heated after being firstly heated to 60&#xb0; C. followed by cooling in differential scanning calorimetry (DSC), the toner has a clear peak specific to melting of the crystalline resin at a temperature T1, and when the toner is heated after being firstly heated to 80&#xb0; C. followed by cooling in the differential scanning calorimetry (DSC), the toner does not have a clear peak specific to melting of the crystalline resin at a temperature not higher than the temperature T1.

Toner, and image forming method, process cartridge, and image forming apparatus using the toner

Image forming apparatus, image forming method and process cartridge

A developing roller, including: a shaft containing a metal; an elastic layer on a circumference of the shaft; and a surface layer on a circumferential surface of the elastic layer, wherein the surface layer contains: a polyurethane which is a reaction product between a fluoroethylene vinyl ether copolymer and an isocyanurate form of an isocyanate; and particles having an average primary particle diameter of 5 nm to 30 nm, and wherein the polyurethane has a peak intensity ratio of a NCO group to a hydroxyl group of 5.6 to 8.8 in an infrared absorption spectrum obtained by an attenuated total reflection method.

Developing roller, developing device, process cartridge, and image forming apparatus

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Hyogo, Japan

Yuta Takeuchi