Patents by Inventor Hitoshi Iwatsuki

Hitoshi Iwatsuki has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20150153665
    Abstract: 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.
    Type: Application
    Filed: June 26, 2013
    Publication date: June 4, 2015
    Inventors: Hiroyuki Kishida, Shigenori Yaguchi, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano
  • Patent number: 9029061
    Abstract: A carrier for use in a two component developer for developing an electrostatic latent image is provided. The carrier includes a particulate core material; and a cover layer located on a surface of the core material and including a silicone resin and barium sulfate. The cover layer includes Ba and Si at an atomic ratio of from 0.01 to 0.08 as determined by X-ray photoelectron spectroscopy.
    Type: Grant
    Filed: December 27, 2010
    Date of Patent: May 12, 2015
    Assignee: Ricoh Company, Limited
    Inventors: Koichi Sakata, Minoru Masuda, Hisashi Nakajima, Kimitoshi Yamaguchi, Yutaka Takahashi, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano
  • Patent number: 8918025
    Abstract: 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.
    Type: Grant
    Filed: July 13, 2012
    Date of Patent: December 23, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Tohmatsu, Shigenori Yaguchi, Hitoshi Iwatsuki, Toyoaki Tano, Koichi Sakata, Mariko Takii
  • Patent number: 8916325
    Abstract: 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 (SnO2), 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.
    Type: Grant
    Filed: March 8, 2013
    Date of Patent: December 23, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigenori Yaguchi, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Hiroyuki Kishida, Toyoaki Tano
  • Patent number: 8903270
    Abstract: A developing device including a developer bearing member containing a magnetic field generator having multiple magnetic poles and a developer containing chamber is provided. The developer containing chamber contains a two-component developer comprising magnetic carrier particles having a saturated magnetization of 58 to 70 emu/g in a magnetic field of 1KOe and toner particles, and has a divider to define an upper supply chamber and a lower collection chamber. The supply chamber includes a supply conveyer to supply the two-component developer to the developer bearing member at an upstream side from the developing area. The collection chamber includes a collection conveyer to collect the two-component developer from the developer bearing member at a downstream side from the developing area. The multiple magnetic poles includes three developer bearing poles capable of bearing the developer on its surface.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: December 2, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Koichi Sakata, Shigenori Yaguchi, Toyoshi Sawada, Hitoshi Iwatsuki, Hiroyuki Kishida
  • Publication number: 20140348552
    Abstract: A replenishing developer housing container according to the present invention includes: a container body housing a replenishing developer; a conveying portion; a pipe receiving port; and an uplifting portion, wherein the replenishing developer contains a toner and a carrier, wherein 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, wherein the uplifting portion includes an uplifting wall surface extending from an internal wall surface of the container body toward the protruding portion, wherein the protruding portion is provided such that 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.
    Type: Application
    Filed: May 16, 2014
    Publication date: November 27, 2014
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hitoshi Iwatsuki, Shigenori YAGUCHI, Hiroshi TOHMATSU, Toyoaki TANO, Hiroyuki KISHIDA, Kenichi MASHIKO, Koichi SAKATA, Hiroshi HOSOKAWA, Shunji KATOH, Shinji TAMAKI, Hiroshi IKEGUCHI, Kenji KIKUCHI, Michiharu SUZUKI
  • Patent number: 8877418
    Abstract: The developing method includes developing an electrostatic latent image on an image bearing member with a two-component developer including a toner and a carrier and born on at least one developer bearing member, whose surface moves at a linear speed of from 300 mm/sec to 2,000 mm/sec. The carrier includes a particulate core material; and a cover layer located on a surface of the core material and including a crosslinked material obtained by crosslinking a resin including a first unit having a specific tris(trialkylsiloxy) silyl group and a second unit having a specific alkoxysilyl group having a crosslinking ability. Each of the first unit and the second unit is included in the resin in a molar ratio of from 0.1 to 0.9 based on all the units included in the resin.
    Type: Grant
    Filed: July 19, 2011
    Date of Patent: November 4, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Hisashi Nakajima, Kimitoshi Yamaguchi, Shigenori Yaguchi, Hitoshi Iwatsuki, Toyoaki Tano, Mariko Takii, Minoru Masuda, Koichi Sakata, Saori Yamada, Hiroyuki Kishida
  • Publication number: 20140248557
    Abstract: 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%.
    Type: Application
    Filed: January 29, 2014
    Publication date: September 4, 2014
    Inventors: Shigenori Yaguchi, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano, Hiroyuki Kishida, Kenichi Mashiko, Hiroshi Tohmatsu
  • Publication number: 20140227638
    Abstract: 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 m2/g.
    Type: Application
    Filed: December 16, 2013
    Publication date: August 14, 2014
    Inventors: Hiroyuki KISHIDA, Shigenori Yaguchi, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano, Kenichi Mashiko
  • Patent number: 8778587
    Abstract: 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 [?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 2×4 [cm2] 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 ?m.
    Type: Grant
    Filed: October 10, 2012
    Date of Patent: July 15, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Shigenori Yaguchi, Toyoshi Sawada, Hiroshi Tohmatsu, Hitoshi Iwatsuki, Toyoaki Tano
  • Publication number: 20140080052
    Abstract: A carrier for developing electrostatic latent images produced in an image developer includes a magnetic particulate core material and a covering layer covering the surface of the core material. The image developer includes an image bearer, a developer bearer including comprising a magnetic field generator inside and a developer regulation member facing the surface of the image developer with a predetermined gap. The carrier has a bulk density of from 1.6 to 2.25 g/cm3, a BET specific surface area of from 0.5 to 2.0 m3/g, a saturated magnetization (?5000) not less than 70 emu/g at 5 kOe, and a residual magnetization (?r) not greater than 2 emu/g.
    Type: Application
    Filed: August 7, 2013
    Publication date: March 20, 2014
    Inventors: Shigenori YAGUCHI, Hiroshi TOHMATSU, Koichi SAKATA, Hitoshi IWATSUKI, Hiroyuki KISHIDA, Toyoaki TANO, Kenichi MASHIKO
  • Publication number: 20140072910
    Abstract: 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 ?m to 3.0 ?m, and wherein the carrier for developing an electrostatic latent image has an arithmetic mean surface roughness Ra1 of 0.5 ?m to 0.9 ?m.
    Type: Application
    Filed: June 26, 2013
    Publication date: March 13, 2014
    Inventors: Hitoshi IWATSUKI, Shigenori Yaguchi, Toyoaki Tano, Mariko Takii, Koichi Sakata, Hiroyuki Kishida, Hiroshi Tohmatsu
  • Patent number: 8663892
    Abstract: 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/cm3 to 2.4 g/cm3, 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 ?m to 1.0 ?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.
    Type: Grant
    Filed: August 23, 2012
    Date of Patent: March 4, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hitoshi Iwatsuki, Toyoaki Tano, Hiroshi Tohmatsu
  • Patent number: 8652735
    Abstract: 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.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: February 18, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Koichi Sakata, Shigenori Yaguchi, Toyoshi Sawada, Kimitoshi Yamaguchi, Hitoshi Iwatsuki, Hiroshi Tohmatsu, Hiroyuki Kishida, Toyoaki Tano, Mariko Takii
  • Patent number: 8652738
    Abstract: 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.
    Type: Grant
    Filed: July 13, 2011
    Date of Patent: February 18, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Shigenori Yaguchi, Hitoshi Iwatsuki, Mariko Takii, Toyoshi Sawada, Toyoaki Tano, Hiroshi Tohmatsu, Koichi Sakata, Hiroyuki Kishida, Saori Yamada
  • Publication number: 20140023966
    Abstract: 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 ?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.
    Type: Application
    Filed: July 1, 2013
    Publication date: January 23, 2014
    Inventors: Toyoshi SAWADA, Shigenori Yaguchi, Hiroshi Tohmatsu, Hitoshi Iwatsuki, Toyoaki Tano, Hiroyuki Kishida, Yumiko Yagi
  • Publication number: 20130252169
    Abstract: 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 (SnO2), 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.
    Type: Application
    Filed: March 8, 2013
    Publication date: September 26, 2013
    Inventors: Shigenori Yaguchi, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Hiroyuki Kishida, Toyoaki Tano
  • Patent number: 8518626
    Abstract: The carrier is used for a two-component developer for developing an electrostatic latent image, and includes a particulate magnetic core material; and a cover layer located on a surface of the particulate magnetic core material and including a crosslinked material. The crosslinked material is formed by hydrolyzing a copolymer including at least a unit (A) having a specific acrylic siloxane structure including a tris(trialkylsiloxy)silanyl group and a unit (B) having a specific acrylic silicone structure to form a material having a silanol group, and subjecting the material having a silanol group to a condensation reaction using an organic zirconium-containing catalyst.
    Type: Grant
    Filed: March 1, 2011
    Date of Patent: August 27, 2013
    Assignee: Ricoh Company, Limited
    Inventors: Saori Yamada, Minoru Masuda, Hisashi Nakajima, Kimitoshi Yamaguchi, Koichi Sakata, Hitoshi Iwatsuki, Yutaka Takahashi, Toyoaki Tano, Mariko Takii
  • Patent number: 8512929
    Abstract: A latent electrostatic image developing carrier including a carrier core material, and a coating layer containing a resin and provided on a surface of the carrier core material, wherein the coating layer includes a particulate material containing at least first fine conductive particles and second fine conductive particles, and wherein the first fine conductive particles and the second fine conductive particles satisfy the relationships expressed by Expressions 1 and 2, 3?D1/D2?15 . . . Expression 1, where D1 denotes a dispersed particle diameter of the first fine conductive particles and D2 denotes a dispersed particle diameter of the second fine conductive particles, and ?7E?R1×R2?8E . . . Expression 2, where R1 denotes a powder specific resistance of the first fine conductive particles and R2 denotes a powder specific resistance of the second fine conductive particles.
    Type: Grant
    Filed: September 10, 2010
    Date of Patent: August 20, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Hitoshi Iwatsuki, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata, Toyoaki Tano
  • Patent number: 8512928
    Abstract: A carrier comprising a magnetic core particle having a shape factor SF-2 of 130 to 160 and a resin layer covering a surface of the magnetic core particle. The resin layer comprises a conductive particle and a resin obtained by heating a copolymer comprising a silicon-containing A unit and another silicon-containing B unit.
    Type: Grant
    Filed: September 6, 2011
    Date of Patent: August 20, 2013
    Assignee: Rocoh Company, Ltd.
    Inventors: Hiroyuki Kishida, Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano, Mariko Takii