Ricoh Company, Ltd.

Rocoh Company, Ltd.

Hiroshi Tohmatsu

Toyoaki Tano

Koichi Sakata

Hiroyuki Kishida

Toyoshi Sawada

Kenichi Mashiko

Hiroshi Hosokawa

Yutaka Takahashi

Hitoshi Iwatsuki

Shigenori Yaguchi

Mariko Takii

Kimitoshi Yamaguchi

Shinji Okada

Hideo Aihara

Hirokazu Watari

Ichiro Sawamura

Keiichi Shiokawa

Yoshihiro Murasawa

Susumu Kawakami

Yoji Ide

Hironori Hata

Shigekazu Teranishi

Yoichi Iwaki

Toshio Koike

Kenji Kikuchi

Shinji Tamaki

Shunji Katoh

Hiroshi Ikeguchi

Michiharu Suzuki

Saori Yamada

Keinosuke Kondoh

Tohru Suganuma

Shohichi Sugimoto

Yumiko Yagi

Kazuyoshi Inamura

Katsushi Shishido

Norihiro Ohtsuka

Toru Nagahashi

Yoshiro Takesue

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 developing device, including: a developer containing toner and carrier; and developer bearer configured to have surface thereof bear the developer and endlessly move, and to develop latent image over surface of latent image bearer by supplying toner in developer to latent image in developing region facing the latent image bearer, wherein carrier contains fine particles, value X in volume resistivity R (=10) (&#x3a9;&#xb7;cm) of carrier is 11.5-16.0, developer bearer includes: magnetic field generating unit including a plurality of magnetic poles; and developing sleeve having a cylindrical shape enclosing magnetic field generating unit, and configured to bear developer over outer circumferential surface of cylindrical shape by magnetic force of the magnetic field generating unit and perform surface moving by rotating relative to developing device body, and developing device includes developing sleeve voltage applying unit configured to apply AC component-containing voltage to developing sleeve.

Developing device and image forming apparatus

Provided is an electrostatic latent image developing white toner, including: a white toner including at least a binder resin, a white pigment, and a release agent; and a magnetic carrier including at least a core material, and a coating layer coating the core material and made of a coating resin and conductive particles, wherein Ra of the magnetic carrier is in a range of from 0.50 &#x3bc;m to 1.00 &#x3bc;m, and a bulk density of the magnetic carrier is in a range of from 2.08 g/cmto 2.24 g/cm.

Electrostatic latent image developing white developer, image forming method, image forming apparatus, and process cartridge

There is provided a carrier including magnetic core particles; and a coating layer on a surface of each of the magnetic core particles, wherein the coating layer contains electroconductive particles; wherein the electroconductive particles are electroconductive particles in which white inorganic pigments are coated with phosphorus-doped tin or tungsten-doped tin; and wherein a dope ratio of phosphorus or tungsten to tin in the phosphorus-doped tin or tungsten-doped tin is 0.010 to 0.100.

Carrier, two-component developer, supplemental developer, image forming method, process cartridge and image forming apparatus

A carrier for developing an electrostatic latent image of the present invention includes a core material and a coating layer which coats the core material, wherein the coating layer includes a resin and fine particles, wherein the coating layer has an average layer thickness difference of 0.02 &#x3bc;m to 3.0 &#x3bc;m, and wherein the carrier for developing an electrostatic latent image has an arithmetic mean surface roughness Ra1 of 0.5 &#x3bc;m to 0.9 &#x3bc;m.

Carrier for developing an electrostatic latent image, developer and image forming apparatus

A carrier is provided. The carrier includes a particulate magnetic core, and a cover layer located on the surface of the particulate magnetic core and including a resin and a filler. When determined from observation of cross-section of the carrier, the shape factor SF2 of the carrier is from 120 to 160, the ratio of the average domain diameter of the particulate magnetic core to the number average particle diameter of the filler is from 1:1 to 1:0.003, and the area ratio of the filler in the cover layer is from 30 to 85%.

Carrier for two-component developer, two-component developer using the carrier, and image forming method and process cartridge using the two-component developer

A replenishing developer housing container includes: a container body housing a replenishing developer; a conveying portion; a pipe receiving port; and an uplifting portion. The replenishing developer contains a toner and a carrier. The container body includes a protruding portion protruding from a container body interior side of the container opening portion toward one end of the container body and a curving portion curving so as to conform to the protruding portion. The uplifting portion includes an uplifting wall surface extending from an internal wall surface of the container body toward the protruding portion. When the replenishing developer housing container is mounted on the replenishing developer conveying device, the protruding portion is present between the curving portion and the replenishing developer receiving port of a conveying pipe being inserted.

Replenishing developer housing container and image forming apparatus

A carrier for use in a two-component developer for developing an electrostatic latent image is provided. The carrier includes a particulate magnetic core; and a cover layer located on a surface of the particulate magnetic core and including a resin and a particulate electroconductive material. The carrier has a BET specific surface area of from 0.8 to 1.6 m/g.

Carrier for two-component developer, two-component developer using the carrier, and process cartridge and image forming method and apparatus using the two component developer

A carrier for developing electrostatic latent images includes a core material; and a covering layer formed of a resin comprising an electroconductive particulate material, overlying the core material, wherein the covering layer includes the electroconductive particulate material in an amount of from 58 to 73% by weight and has a resistivity of from 6.6 to 8.6 &#x3a9;cm, and wherein the carrier has a high-brightness contrast part at an areal ratio less than 1% and 40 to 90% based on total area thereof at an acceleration voltage of 0.8 KV and 2.0 KV, respectively in an FE-SEM reflection electron image of the surface thereof.

Carrier for developing electrostatic latent image, and electrostatic latent image developer

A carrier for developing electrostatic latent image, including a particulate magnetic core material; and a coated layer covering the surface of the particulate magnetic core material, wherein the coated layer includes a resin including a silicone resin and a methacrylic ester or an acrylic ester resin, and a filler including a substrate; and an electroconductive layer comprising tin dioxide (SnO), overlying the substrate, and wherein the carrier includes tin (Sn) in an amount not less than 0.5% by atom and has a ratio (Sn/Si) of tin (Sn) to silicon (Si) of from 0.03 to 0.2 when subjected to an XPS analysis.

Carrier for developing electrostatic latent image, tow-component developer and image forming method

To provide an image forming method, containing: a charging step, a latent electrostatic image forming step, a developing step, a transferring step, and a fixing step, wherein the developing step is developing the latent electrostatic image formed on the latent electrostatic image bearing member with a two-component developer containing a toner and a carrier by a developing element to form a visible image, where the developing contains: stirring the toner and the carrier to prepare the two-component developer to have a flow energy amount of 30 mJ to 70 mJ; and periodically discharging and transporting the stirred two-component to the developer unit by air pressure to thereby supply the two-component developer for the developing.

Image forming method and image forming apparatus

A carrier for developing an electrostatic latent image, including a particulate core material having a magnetism having developed spontaneous magnetization; and a covering layer comprising an electroconductive material, covering the surface of the particulate core material, wherein the carrier has an electrical resistivity Log R [&#x3a9;cm] of from 8.0 to 12.0 when measured by a method, including filling the carrier in a cell containing a pair of facing electrodes, each having a surface area of 2&#xd7;4 [cm] with a gap of 2 [mm] therebetween; and applying a DC voltage of 1,000 [V] therebetween to measure a DC resistivity, and a weight-average particle diameter (Dw) of from 25 to 45 &#x3bc;m.

Carrier for electrostatic latent image developer, electrostatic latent image developer formed of carrier and toner, and process cartridge using the developer

A latent electrostatic image developing carrier including: core particles each having magnetism; and a coating layer covering each of the core particles, wherein the latent electrostatic image developing carrier has a shape factor SF-2 of 115 to 150 and has a bulk density of 1.8 g/cmto 2.4 g/cm, wherein the core particles have a shape factor SF-2 of 120 to 160 and have an arithmetic mean surface roughness Ra of 0.5 &#x3bc;m to 1.0 &#x3bc;m, and wherein the coating layer contains a resin and a filler and an amount of the filler contained in the coating layer is 50 parts by mass to 500 parts by mass per 100 parts by mass of the resin contained in the coating layer.

Latent electrostatic image developing carrier, process cartridge and image forming apparatus

A carrier including a magnetic core particle and a resin layer covering a surface of the magnetic core particle. The magnetic core particle is a ferrite particle including strontium in an amount of 0.005 to 3% by mass, measured by fluorescent X-ray spectroscopy. The resin layer comprises a resin obtained by heating a copolymer comprising a silicon-containing unit A and another silicon-containing specific unit B.

Carrier, developer, method of manufacturing carrier, developer container, image forming method, process cartridge, image forming apparatus, and supplemental developer

A contact developing method including supplying a two-component developer to an electrostatic latent image on a rotating image bearing member by rotating a developing sleeve and a rotatable magnet having multiple magnetic poles provided inside the developing sleeve, to develop the electrostatic latent image into a toner image. The developing sleeve and the image bearing member rotate in the same direction while facing each other. The two-component developer comprises a non-magnetic toner and a carrier. The carrier comprises a magnetic core particle and a resin layer covering the magnetic core particle. The resin layer comprises a conductive particle and a resin. The conductive particle comprises an alumina-based material and a conductive layer covering the alumina-based material. The resin is obtained by heating a copolymer comprising a monomer A unit and a monomer B unit.

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Shizuoka, Japan

Hiroshi Tohmatsu