Ricoh Company, Ltd.

Shohichi Sugimoto

Shinichi Kuramoto

Koichi Sakata

Osamu Uchinokura

Masayuki Ishii

Hiroyuki Kishida

Toyoaki Tano

Hiroshi Tohmatsu

Kumi Hasegawa

Satoru Miyamoto

Kenichi Mashiko

Tohru Suganuma

Noboru Kuroda

Yoshihiro Suguro

Kohtaroh Ogino

Hideyuki Ueda

Tamotsu Kajihara

Masayuki Kakimoto

A toner is provided which includes: a toner base particle including a binder resin; and an external additive including inorganic particles. A particle size distribution of primary particles of the inorganic particles has a plurality of peaks in the range of from 5 nm through 50 nm. The particle size distribution of the primary particles satisfies all of expressions (1) to (3) below:12&#x2003;&#x2003;(1);10&#x3c;(12)&#x2003;&#x2003;(2); and30&#x2264;{(21)&#xd7;100}&#x3c;100&#x2003;&#x2003;(3),

Toner, developer, toner stored unit, image forming apparatus, image forming method, and printed matter producing method

A carrier including a resin layer including at least one kind of particles, wherein the at least one kind of the particles are particles of barium sulfate, wherein an amount of Ba detected is 0.3 atomic % or greater in a Ba analysis through X-ray photoelectron spectroscopy (XPS) of the carrier, and wherein circle-equivalent diameters of the particles of the barium sulfate are 400 nm or greater but 900 nm or smaller.

Carrier, developer, image forming apparatus, developer stored unit, and image forming method

A toner including toner particles including at least a binder resin having a first melting point and a first solubility parameter, a colorant and a particulate release agent having a second melting point lower than the first melting point and a second solubility parameter different from the first solubility parameter, wherein the particulate release agent dispersed in the toner particles has an average needle-shape degree LD/SD of not less than 1.6, where LD is a diameter of a particle of the release agent dispersed in the toner in a major axis direction thereof and SD is a diameter of the particle in a minor axis direction.

Electrophotographic toner and image forming method using the toner

An image formation method for forming a full-color image includes the step of superimposing four yellow, magenta, cyan and black toner images which are respectively obtained by developing four latent electrostatic images, which respectively correspond to the four yellow, magenta, cyan and black toner images, with a yellow toner, a magenta toner, a cyan toner and a black toner, wherein a gradient a,of a yellow glossiness per unit amount of the yellow toner (mg/cm,) deposited on a transfer sheet, a gradient a,of a magenta glossiness per unit amount of the magenta toner (mg/cm,) deposited on the transfer sheet, and a gradient a,of a cyan glossiness per unit amount of the cyan toner (mg/cm,) deposited on the transfer sheet are in a range of 0.8 a to 1.2 a, and a gradient a,of a black glossiness per unit amount of the black toner (mg/cm,) deposited on the transfer sheet is in a range of 0.4 a to 0.7 a, in which a&equals;(a,&plus;a,&plus;a,)/3.

Full-color electrophotographic image formation method, color toners for use in the same, and color image formed by use of the color toners

A dry toner for electrophotography includes a coloring agent, a releasing agent, and a polyol resin having a polyoxy alkylene moiety in a main chain thereof, with a ratio of Mw/Mn of 4 to 10, serving as a binder resin, which is synthesized by allowing an epoxy resin, a dihydric phenol, and an alkylene oxide adduct of a dihydric phenol, or a glycidyl ether thereof to react.

Dry toner for electrophotography

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Shizuoka, Japan

Shohichi Sugimoto