Patents by Inventor Masashi Nagayama

Masashi Nagayama 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).

  • Patent number: 8039189
    Abstract: The present invention can provide small-diameter core material particles for electro photographic carrier, the particles that can prevent occurrences of carrier adhesions and reduce toner spent, have excellent durability and cause little fluctuations in image density with a narrow particle diameter distribution, and an efficient, cost-effective production method thereof. That is, the core material particles for electro photographic carrier are particles wherein the weight average particle diameter, Dw, is in the range of 22 ?m to 32 ?m, the ratio of Dw to the number average particle diameter, Dp, satisfies the condition, 1<Dw/Dp<1.20, the content of particles smaller than 20 ?m in diameter is in the range of 0% by mass to 7% by mass and smaller than 36 ?m is in the range of 90% by mass to 100% by mass, and the BET specific surface area is in the range of 300 cm2/g to 900 cm2/g.
    Type: Grant
    Filed: April 17, 2007
    Date of Patent: October 18, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Naoki Imahashi, Masashi Nagayama
  • Patent number: 8026032
    Abstract: A carrier for use in an image forming apparatus in which a toner and a carrier are fed to an image developer thereof and an extra developer including the toner and the carrier in the image developer is discharged therefrom, wherein at least one of the carrier fed to the image developer and a carrier readily contained therein includes a core material; and a coated film coating the core material, and wherein the coated film includes a binder resin and a particulate material having a ratio of an average particle diameter thereof to an average thickness of the coated film of from 0.01 to 1, and includes concavities and convexities having an average difference of elevation of from 0.02 to 3.0 ?m.
    Type: Grant
    Filed: October 11, 2007
    Date of Patent: September 27, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Hitoshi Iwatsuki, Tomio Kondou, Shinichiro Yagi, Masashi Nagayama
  • Publication number: 20110058831
    Abstract: An apparatus includes: an image carrier; a charger to uniformly charge a surface of the image carrier; an exposing unit to perform write scanning on the image carrier; a developing unit that includes a developer carrier carrying a developer including a toner and that is configured to perform a visible image process on an electrostatic latent image formed on the image carrier; and a transferor to transfer a toner image that has been subjected to the process onto a material. If length Lg of a non-image part directly before an image part in an image carrier moving direction has the relation of Lg??·Ds/(Vs/Vp), where Vp and Vs are circumferential velocities of the image carrier and the developer carrier and Ds is a diameter of the developer carrier, suppression of toner attachment on the material is controlled in a predetermined length from an image front end in the direction.
    Type: Application
    Filed: September 9, 2010
    Publication date: March 10, 2011
    Inventors: Motohiro USAMI, Takahiro Seki, Masashi Nagayama, Shinji Aoki, Jun Hitosugi
  • Patent number: 7763410
    Abstract: A vibrating sieve for classifying a particulate material, including an oscillator comprising a transducer; and at least two meshes layered together and located in contacting relation to a transducer, wherein a lowermost mesh receiving a vibration from the transducer transmits the vibration to an uppermost mesh to classify the particulate material fed thereon.
    Type: Grant
    Filed: November 1, 2004
    Date of Patent: July 27, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Masashi Nagayama, Naoki Imahashi
  • Publication number: 20090232526
    Abstract: A developer cartridge is provided, which contains developer made of toner and carrier and is detachably mounted in a body of an image formation apparatus. The developer cartridge is configured to include an ID chip in which a carrier content rate of the developer contained in an inner container of the developer cartridge is stored.
    Type: Application
    Filed: March 17, 2009
    Publication date: September 17, 2009
    Inventors: Takuzi Yoneda, Mugijirou Uno, Kousuke Suzuki, Shinichiro Yagi, Masashi Nagayama, Hitoshi Iwatsuki
  • Publication number: 20090142678
    Abstract: To provide an electrophotographic developer carrier including a carrier core material, and a coat layer containing a binder resin and conductivity-imparted microparticles which are produced by imparting conductivity to inorganic microparticles, the coat layer being formed over the carrier core material, wherein the electrophotographic developer carrier has a static resistivity of 10 [Log (?·cm)] or higher and a dynamic resistivity of 9 [Log (?)] or lower, and is used in an electrophotographic developer together with a negatively chargeable toner having an average circularity of 0.925 to 0.970, and wherein the toner includes a resin, a colorant and an inorganic layered mineral in which at least part of interlayer ions is modified with organic ions, and is granulated by dispersing and/or emulsifying an oil phase and/or a monomer phase containing at least a toner composition and/or a toner composition precursor in an aqueous medium.
    Type: Application
    Filed: December 2, 2008
    Publication date: June 4, 2009
    Inventors: Shinichiro Yagi, Kousuke Suzuki, Masashi Nagayama
  • Publication number: 20090092920
    Abstract: The present invention is to provide a carrier and a developer, which have fewer occurrences of carrier adhesion and background smear, excellent granularity and longer durability. The carrier comprises the core material particles having magnetism and resin coating layer covering the core material particles, and wherein the weight average particle diameters is in the range of 22 m to 32 m, the proportion of the weight average particle diameters relative to the number average particle diameter is in the range of 1.00 to 1.20, the content of particles having a diameter of 20 m or smaller is 7% by mass, the content of carrier particles having a diameter of 36 m or smaller is in the range of 90% by mass to 100% by mass, and the proportion of the particle density of the core material particles is in the range of 85% to 100% of the true density of the core material particles.
    Type: Application
    Filed: March 6, 2007
    Publication date: April 9, 2009
    Inventors: Masashi Nagayama, Kimitoshi Yamaguchi, Naoki Imahashi
  • Publication number: 20090074450
    Abstract: An image forming apparatus including an image bearing member; and a developing device including a developer bearing member, a developer containing portion, a developer supplying passage supplying the developer to the developer bearing member while feeding the developer in a direction, and a developer agitating passage feeding a mixture of the developer fed through the developer supplying passage without used for developing, and the developer used for developing, in the opposite direction. The developer supplying passage, and developer agitating passage are separated from each other except for at least both the end portions. The developer includes a toner and a carrier having a cover layer thereon, which includes a binder resin and a particulate material. The ratio of the volume average particle diameter of the particulate material to the average thickness of the resinous portion of the cover layer is greater than 1 and less than 10.
    Type: Application
    Filed: September 12, 2008
    Publication date: March 19, 2009
    Inventors: Masashi NAGAYAMA, Tomio Kondou, Shinichiro Yagi, Hitoshi Iwatsuki
  • Patent number: 7468233
    Abstract: Electro-photographic images having high picture quality and low carrier adhesion can be obtained using a two-component developer containing a carrier containing (A) a carrier containing a core containing a magnetic material, the core being coated with at least one resin layer; and (B) a toner; wherein the carrier has a weight average particle diameter Dw of 22-32 ?m; wherein a content of carrier particles having a diameter smaller than 20 ?m is 0-7% by weight based on the weight of the carrier; wherein a content of carrier particles having a diameter smaller than 36 ?m is 90-100% by weight based on the weight of the carrier; wherein a weight average particle diameter Dw of the toner is 2-7 ?m; and wherein a ratio Dw/Dn of the weight average particle diameter of the toner to the number average particle diameter of the toner is 1.00-1.25.
    Type: Grant
    Filed: September 12, 2005
    Date of Patent: December 23, 2008
    Assignee: Ricoh Company, Ltd.
    Inventors: Masashi Nagayama, Kimitoshi Yamaguchi, Naoki Imahashi
  • Publication number: 20080213682
    Abstract: Provided is a toner for developing electrostatic image, comprising particles of oil phase containing at least a toner composition and/or toner composition precursor in an aqueous medium, wherein the toner composition and/or toner composition precursor comprises an organic-modified layered inorganic mineral prepared by modifying at least partially an ion of a layered inorganic mineral into an organic ion, and the organic ion-modification ratio X satisfies the relation of 100<X(%)<150 in the organic-modified layered inorganic mineral.
    Type: Application
    Filed: February 29, 2008
    Publication date: September 4, 2008
    Inventors: Akinori SAITOH, Masahide Yamada, Osamu Uchinokura, Junichi Awamura, Tomomi Suzuki, Shinichiro Yagi, Tomio Kondou, Masashi Nagayama, Hitoshi Iwatsuki
  • Publication number: 20080213684
    Abstract: To provide a carrier for electrophotographic developer including core particles and a cover layer covering the particles, wherein at least one of the carrier to be supplied in a developing apparatus and carrier contained in the developing apparatus has a weight average particle diameter Dw of 22 ?m or more and 32 ?m or less, a ratio Dw/Dp of the weight average particle diameter Dw to the number average particle diameter Dp that satisfies the relationship 1.00?Dw/Dp?1.20, particles whose particle diameter x (?m) is within a range of 0<x<20 in an amount of 7 wt % or less, and particles whose particle diameter y (?m) is within a range of 0<y<36 in an amount of 90 wt % or more and 100 wt % or less.
    Type: Application
    Filed: January 16, 2008
    Publication date: September 4, 2008
    Inventors: Masashi NAGAYAMA, Tomio Kondou, Shinichiro Yagi, Hitoshi Iwatsuki
  • Publication number: 20080171274
    Abstract: An image forming apparatus including at least an image bearer; a charger charging the image bearer; an irradiator irradiating the image bearer to form an electrostatic latent image thereon; an image developer developing the electrostatic latent image with a developer comprising a toner and a carrier to form a toner image on the image bearer; a developer feeder feeding a supplemental developer including the toner and the carrier into the image developer; and a developer collector collecting the developer in the image developer, wherein the developer feeder includes a cylindrical supplemental developer container containing the supplemental developer, including a spiral developer guide race on the inner circumferential surface thereof; and a sub-hopper configured to store the supplemental developer, and wherein the carrier includes a core material; and a layer coated on the core material, including a binder resin and non-black or a non-color inorganic particulate material.
    Type: Application
    Filed: January 11, 2008
    Publication date: July 17, 2008
    Inventors: Shinichiro Yagi, Tomio Kondou, Masashi Nagayama, Hltoahi Iwatsuki
  • Publication number: 20080152393
    Abstract: A carrier for electrophotographic developer that comprises a particle of core material and a coating layer that coats the particle of core material, wherein a toner and a carrier are supplied into a developing device where a toner and a carrier being contained, and the surplus developer within the developing device is discharged, a coating layer on at least one of the supplied carrier and the carrier contained in the developing device comprises a white conductive fine particle that includes tin dioxide and indium oxide on a base material.
    Type: Application
    Filed: December 18, 2007
    Publication date: June 26, 2008
    Inventors: Masashi NAGAYAMA, Tomio Kondou, Shinichiro Yagi, Hitoshi Iwatsuki
  • Patent number: 7386266
    Abstract: An image removing method including bringing an outermost layer of a removing member into contact with an image fixed on an image support without applying a liquid to the image while heating the image and the outermost layer; and separating the removing member from the image support to remove the image from the image support, wherein the removing member includes a substrate and the outermost layer which is located overlying the substrate and which includes a thermoplastic resin, and wherein the image includes a removing agent which can decrease adhesion force of the image to the image support when heated.
    Type: Grant
    Filed: February 10, 2006
    Date of Patent: June 10, 2008
    Assignee: Ricoh Company Limited
    Inventors: Masashi Nagayama, Motoharu Tanaka, Toyoshi Sawada, Keiko Shiraishi, Tadashi Saitoh
  • Publication number: 20080096121
    Abstract: A carrier for use in an image forming apparatus in which a toner and a carrier are fed to an image developer thereof and an extra developer including the toner and the carrier in the image developer is discharged therefrom, wherein at least one of the carrier fed to the image developer and a carrier readily contained therein includes a core material; and a coated film coating the core material, and wherein the coated film includes a binder resin and a particulate material having a ratio of an average particle diameter thereof to an average thickness of the coated film of from 0.01 to 1, and includes concavities and convexities having an average difference of elevation of from 0.02 to 3.0 ?m.
    Type: Application
    Filed: October 11, 2007
    Publication date: April 24, 2008
    Inventors: Hitoshi IWATSUKI, Tomio Kondou, Shinichiro Yagi, Masashi Nagayama
  • Publication number: 20080073252
    Abstract: A vibrating sieve for classifying a particulate material, including an oscillator comprising a transducer; and at least two meshes layered together and located in contacting relation to a transducer, wherein a lowermost mesh receiving a vibration from the transducer transmits the vibration to an uppermost mesh to classify the particulate material fed thereon.
    Type: Application
    Filed: November 20, 2007
    Publication date: March 27, 2008
    Inventors: Kimitoshi YAMAGUCHI, Masashi NAGAYAMA, Naoki IMAHASHI
  • Publication number: 20080063969
    Abstract: A carrier is provided including a core and a resin layer located overlying the core, wherein the carrier has a weight average particle diameter (Dw) of from 22 to 50 ?m, a ratio (Dw/Dp) of the weight average particle diameter (Dw) to a number average particle diameter (Dp) of from 1 to 1.30, a shape factor SF-1 of from 100 to 120, and a shape factor SF-2 of from 100 to 120, and wherein the carrier comprises core particles satisfying the following relationship 0.52<(d/D)<1.0 in an amount of from 0 to 10,000 ppm by number: wherein D (?m) represents a diameter of a circle having the same area as that of a projected image of a core particle and d (?m) represents a diameter of a circle having the same area as that of a projected image of a maximum hollow present in the core particle.
    Type: Application
    Filed: August 31, 2007
    Publication date: March 13, 2008
    Inventors: Kimitoshi Yamaguchi, Naoki Imahashi, Masashi Nagayama
  • Publication number: 20070243482
    Abstract: The present invention can provide small-diameter core material particles for electrophotographic carrier, the particles that can prevent occurrences of carrier adhesions and reduce toner spent, have excellent durability and cause little fluctuations in image density with a narrow particle diameter distribution, and an efficient, cost-effective production method thereof. That is, the core material particles for electrophotographic carrier are particles wherein the weight average particle diameter, Dw, is in the range of 22 ?m to 32 ?m, the ratio of Dw to the number average particle diameter, Dp, satisfies the condition, 1<Dw/Dp<1.20, the content of particles smaller than 20 ?m in diameter is in the range of 0% by mass to 7% by mass and smaller than 36 ?m is in the range of 90% by mass to 100% by mass, and the BET specific surface area is in the range of 300 cm2/g to 900 cm2/g.
    Type: Application
    Filed: April 17, 2007
    Publication date: October 18, 2007
    Inventors: Kimitoshi YAMAGUCHI, Naoki Imahashi, Masashi Nagayama
  • Patent number: 7235338
    Abstract: A toner prepared by a method of dissolving or dispersing toner constituents comprising a modified resin capable of reacting with an active hydrogen and a colorant which is a black metallic material to prepare a solution or a dispersion; and reacting the solution or dispersion with at least one of a crosslinking agent and an elongation agent in an aqueous medium including a resin particulate material.
    Type: Grant
    Filed: June 30, 2004
    Date of Patent: June 26, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Takeshi Takada, Masahiro Ohki, Toyoshi Sawada, Keiko Shiraishi, Masashi Nagayama
  • Patent number: 7217485
    Abstract: A toner for electrophotography contains a binder resin, a charge control agent, and a colorant. The colorant is a black iron oxide compound containing 10 to 45% by weight of titanium component calculated in terms of Ti atom in relation to Fe atom when measured by wavelength dispersive X-ray fluorescence spectrometry. Peaks at Bragg angle 2? of the toner to CuK? X-ray are peak A at 32.9 degrees ±0.3 degrees and peak B at 35.5 degrees ±0.3 degrees, and X ray intensity ratio between peaks A and B (A/B) is in the range of 0.3 to 2.0 at a scan speed of 0.5 to 4 degrees/min.
    Type: Grant
    Filed: March 16, 2004
    Date of Patent: May 15, 2007
    Assignee: Ricoh Company, Ltd.
    Inventors: Kumi Hasegawa, Mitsuo Aoki, Bing Shu, Toyoshi Sawada, Keiko Shiraishi, Masashi Nagayama, Shinichi Kuramoto