Patents by Inventor Koichi Sakata

Koichi Sakata 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: 20110229817
    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: Application
    Filed: March 1, 2011
    Publication date: September 22, 2011
    Inventors: Saori YAMADA, Minoru Masuda, Hisashi Nakajima, Kimitoshi Yamaguchi, Koichi Sakata, Hitoshi Iwatsuki, Yutaka Takahashi, Toyoaki Tano, Mariko Takii
  • Publication number: 20110217649
    Abstract: The present invention provides a carrier which includes core material particles, and a coating layer on surfaces of the core material particles, wherein the coating layer contains a crosslinked product which is obtained by condensation of a cone resin with an organic zirconium catalyst, the silicone resin having at least one of a silanol group and a functional group capable of generating a silanol group by means of hydrolysis.
    Type: Application
    Filed: November 10, 2009
    Publication date: September 8, 2011
    Inventors: Minoru Masuda, Kimitoshi Yamaguchi, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki
  • Publication number: 20110171573
    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: Application
    Filed: December 27, 2010
    Publication date: July 14, 2011
    Inventors: Koichi SAKATA, Minoru Masuda, Hisashi Nakajima, Kimitoshi Yamaguchi, Yutaka Takahashi, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano
  • Patent number: 7962071
    Abstract: A developing device which can stably supply a developer to a latent image carrier by preventing the scattered developer from being discharged and thereby preventing the developer from being discharged despite that the amount of developer within the developing device does not increase, and an image forming apparatus using the developing device. A block member serving as a scattered developer discharge prevention member is provided so as to block a path through which the developer scattered as a result of a conveyance operation of a supply screw serving as a developer conveying member moves toward a developer discharge port. Accordingly, the scattered developer is prevented from reaching the developer discharge port and being discharged therefrom.
    Type: Grant
    Filed: January 25, 2008
    Date of Patent: June 14, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Kiyonori Tsuda, Koichi Kato, Yuki Oshikawa, Yasufumi Takahashi, Eriko Maruyama, Koichi Sakata, Hitoshi Ishibashi, Kentaroh Tomita, Mugijirou Uno, Keiko Matsumoto, Kohichi Utsunomiya
  • Publication number: 20110091802
    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 core material and including a crosslinked material and barium sulfate. The cover layer is formed by applying a coating medium including barium sulfate, a copolymer including 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 having a crosslinking ability, and a condensation reaction catalyst, heating the applied medium to a temperature of from 100° C. to 230° C. so that the copolymer is hydrolyzed to produce a material having a silanol group, and the material and the catalyst are subjected to a condensation reaction to form the crosslinked material.
    Type: Application
    Filed: October 4, 2010
    Publication date: April 21, 2011
    Inventors: Yutaka TAKAHASHI, Minoru Masuda, Kimitoshi Yamaguchi, Hisashi Nakajima, Koichi Sakata, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano, Mariko Takii
  • Publication number: 20110086307
    Abstract: A carrier, including a magnetic particulate core material and a resin layer on the core material, wherein the resin layer includes a resin obtained by heat treatment of a copolymer including a site derived from a monomer component having the following formula (1) and a site derived from a monomer component having the following formula (2), and includes a cross-linked material obtained by hydrolysis of the copolymer to produce a silanol group and condensation using an organotitanium compound: wherein R1 represents a hydrogen atom or a methyl group; m represents an alkylene group having 1 to 8 carbon atoms; R2 represents an alkyl group having 1 to 4 carbon atoms; R3 represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X represents 10 to 90 mol %; and Y represents 10 to 90 mol %.
    Type: Application
    Filed: October 1, 2010
    Publication date: April 14, 2011
    Inventors: Hisashi NAKAJIMA, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki, Saori Yamada, Toyoaki Tano
  • Publication number: 20110065037
    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: Application
    Filed: September 10, 2010
    Publication date: March 17, 2011
    Inventors: Hitoshi Iwatsuki, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata, Toyoaki Tano
  • Publication number: 20110046795
    Abstract: A drive control method of controlling an object which can move at least in a first direction and a second direction different from the first direction is provided. Here, a force applied to the object is controlled on the basis of a driving signal for driving a first actuator moving the object in the first direction and a disturbance correcting signal generated from a disturbance signal in the second direction at an output terminal of the object.
    Type: Application
    Filed: March 8, 2010
    Publication date: February 24, 2011
    Applicants: NATIONAL UNIVERSITY CORPORATION YOKOHAMA NATIONAL UNIVERSITY, NIKON CORPORATION
    Inventors: Hiroshi Fujimoto, Koichi Sakata, Kazuaki Saiki, Takeshi Ohtomo
  • Patent number: 7890028
    Abstract: A developing device and image forming apparatus that can satisfy stability over time in relation to amount of developer carried, and prevent developer retention, deterioration of developer and developing sleeve adhesion, wherein the amount of developer carried per unit area on the developer carrier in the developing region is 30 mg/cm2 to 60 mg/cm2; the weight mean particle diameter of the toner is 4.5 ?m to 8.0 ?m; the ratio Dw/Dn of the toner weight mean particle diameter (Dw) and the number mean particle diameter (Dn) is 1.20 or less; an irregular roughness pattern having the maximum height Rz of the surface roughness of 20 to 40 ?m and the mean space Sm of the roughness of 100 to 200 ?m is formed on the surface of the developer carrier; and the relationship between the developing gap PG and the gap DG between the developer restricting member and the developer carrier is 1.0?(DG/PG)?3.0.
    Type: Grant
    Filed: September 11, 2007
    Date of Patent: February 15, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Satoru Miyamoto, Koichi Sakata, Maiko Koeda, Kiyonori Tsuda
  • Patent number: 7835677
    Abstract: Provided is a developing device containing a two-component developer including a magnetic carrier and a toner; a developer bearing member containing a nonmagnetic developing sleeve configured to bear the two-component developer on a surface thereof while rotating; a magnetic field generating unit fixed inside of the nonmagnetic developing sleeve; and a developer amount control member configured to control an amount of the two-component developer borne on the developer bearing member. The magnetic carrier contains a core material and a coating layer coated on the core material, and the coating layer containing a binder resin and conductive particles. The magnetic carrier satisfy a ratio D/h of 1.00<[D/h]?1.95, where D denotes an average primary particle diameter of the conductive fine particles, and h denotes a thickness of the coating layer, and a ratio Ra/D of 1.0<[Ra/D]<10.0, where Ra denotes a surface roughness of the developing sleeve.
    Type: Grant
    Filed: March 11, 2009
    Date of Patent: November 16, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Koichi Sakata, Tomio Kondou, Shinichiro Yagi
  • Publication number: 20100239975
    Abstract: The carrier includes a particulate core material having magnetism; and a resin layer located on the surface of the particulate core material. The resin layer is prepared by forming a layer including a copolymer, which includes a unit (A) having a specific acrylic siloxane structure, a unit (B) having a specific acrylic silicone structure having a crosslinking ability, and a unit (C) having a specific acrylic structure in a specific ratio, on the particulate core material, and then subjecting the layer to a heat treatment to crosslink the layer.
    Type: Application
    Filed: March 1, 2010
    Publication date: September 23, 2010
    Inventors: Kimitoshi YAMAGUCHI, Minoru MASUDA, Yutaka TAKAHASHI, Koichi SAKATA, Hitoshi IWATSUKI, Toyoaki TANO
  • Publication number: 20100233613
    Abstract: A carrier which is capable of avoiding excess blocking of the carrier particles at the time of forming a covering layer and is excellent in durability, a developer containing the carrier, and a developer container containing the developer, as well as an image forming method and a process cartridge which use the developer are provided. A carrier including at least a core material particle and a covering layer, a surface of the core material particle being covered with the covering layer, wherein the covering layer contains a condensate which is obtained by condensation of a silicone resin having at least one of a silanol group and a functional group which can be converted to the silanol group by hydrolysis, using a titanium diisopropoxy bis(ethylaceto-acetate) catalyst.
    Type: Application
    Filed: March 10, 2010
    Publication date: September 16, 2010
    Inventors: Minoru MASUDA, Kimitoshi Yamaguchi, Yutaka Takahashi, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano
  • Patent number: 7749674
    Abstract: A toner including toner particles including a binder resin, a colorant, and an inorganic particulate material present on a surface of the toner particles. The toner particles have a surface roughness (Ra) of from 1 to 30 nm, a standard deviation of the surface roughness of from 10 to 90 nm and include 1 to 20 convexities per 1 ?m, which have a height not less than 10 nm.
    Type: Grant
    Filed: July 30, 2007
    Date of Patent: July 6, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Publication number: 20100068645
    Abstract: A carrier for developing an electrostatic latent image which includes a core material and a resin coating layer provided on the core material. The resin coating layer includes a resin and a particulate tin oxide, and the surface of the particulate tin oxide is coated with carbon.
    Type: Application
    Filed: September 17, 2009
    Publication date: March 18, 2010
    Inventors: Hitoshi Iwatsuki, Kimitoshi Yamaguchi, Minoru Masuda, Yutaka Takahashi, Koichi Sakata
  • Publication number: 20090324977
    Abstract: A laser-weldable polybutylene terephthalate-series resin composition having a high laser weldability, a high welding strength, and a high heat shock resistance is provided. The laser-weldable PBT-series resin composition comprises (A) a polybutylene terephthalate-series resin and (B) a core-shell polymer (e.g., a core-shell polymer having an acrylic rubber as a core thereof), and if necessary (C) a filler or reinforcing agent (e.g., a glass fiber) and a polycarbonate-series resin. In the resin composition, the core-shell polymer (B) may usually have an average particle size of not less than 2 ?m.
    Type: Application
    Filed: September 6, 2007
    Publication date: December 31, 2009
    Inventor: Koichi Sakata
  • Publication number: 20090232532
    Abstract: Provided is a developing device containing a two-component developer including a magnetic carrier and a toner; a developer bearing member containing a nonmagnetic developing sleeve configured to bear the two-component developer on a surface thereof while rotating; a magnetic field generating unit fixed inside of the nonmagnetic developing sleeve; and a developer amount control member configured to control an amount of the two-component developer borne on the developer bearing member. The magnetic carrier contains a core material and a coating layer coated on the core material, and the coating layer containing a binder resin and conductive particles. The magnetic carrier satisfy a ratio D/h of 1.00<[D/h]?1.95, where D denotes an average primary particle diameter of the conductive fine particles, and h denotes a thickness of the coating layer, and a ratio Ra/D of 1.0<[Ra/D]?10.0, where Ra denotes a surface roughness of the developing sleeve.
    Type: Application
    Filed: March 11, 2009
    Publication date: September 17, 2009
    Inventors: Koichi Sakata, Tomio Kondou, Shinichiro Yagi
  • Patent number: 7566521
    Abstract: To provide a toner that can provide long-term removability and high-definition images with reduced image layer thickness and densely-packed toner particles, a developer capable of forming high-quality images using the toner, a toner container for containing the toner, a process cartridge using the toner, an image forming apparatus using the toner, and an image forming method using the toner. The toner of the present invention is a toner having a substantially spherical shape with irregularities on its surface and containing at least a binder resin and a colorant, wherein a surface factor SF-1 that represents the sphericity of toner particles is 105 to 180, a surface factor SF-2 that represents the degree of surface irregularities of the toner particles is correlated with the volume-average diameter of the toner particles, and the toner particles have an inorganic oxide particle-containing layer within 1 ?m from their surfaces.
    Type: Grant
    Filed: July 13, 2007
    Date of Patent: July 28, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Akihiro Kotsugai, Satoshi Mochizuki, Hisashi Nakajima, Yasuo Asahina, Osamu Uchinokura, Masayuki Ishii, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi, Hitoshi Iwatsuki, Yasuaki Iwamoto, Hideki Sugiura, Masami Tomita
  • Patent number: 7547497
    Abstract: A toner which is negatively charged to develop an electrostatic latent image is provided that contains a colorant; and a binder resin, wherein the toner has an acid value of from 5 to 20 mg KOH/g and an amine value of from 0.5 to 10 mg KOH/g.
    Type: Grant
    Filed: March 16, 2005
    Date of Patent: June 16, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Osamu Uchinokura, Masami Tomita, Hisashi Nakajima, Shinya Nakayama, Koichi Sakata, Akihiro Kotsugai, Tomoyuki Ichikawa, Yasuo Asahina, Hideki Sugiura, Yasuaki Iwamoto, Satoshi Mochizuki
  • Publication number: 20090103943
    Abstract: A two-component developer used in an image forming apparatus including a latent image bearing member and a developing device includes a magnetic carrier and a toner. The toner includes a toner base and inorganic fine particles as an external additive. A loose apparent density of the toner is not greater than 0.39 g/cm3. A coverage of the external additive over the toner base of the toner is not greater than 80% of a surface area of the toner base. An apparent density of the developer is in a range of from 1.55 g/cm3 to 1.70 g/cm3. The developing device includes a developer bearing member, a supply transport path, a circulation transport path, and a partition member.
    Type: Application
    Filed: October 16, 2008
    Publication date: April 23, 2009
    Inventor: Koichi SAKATA
  • Patent number: 7521164
    Abstract: A toner which includes a toner material, wherein the toner satisfies the following formula: 0° C.??Tm?20° C. where ?Tm represents Tma (° C.)?Tmb (° C.), Tma (° C.) is ½ flown-out temperature of the toner by a capillary type flow tester, and Tmb (° C.) is ½ flown-out temperature of a melt kneaded mixture of the toner by the capillary type flow tester, and wherein Tma is from 130° C. to 200° C.
    Type: Grant
    Filed: March 31, 2008
    Date of Patent: April 21, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinya Nakayama, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Akihiro Kotsugai, Masayuki Ishii, Osamu Uchinokura, Hisashi Nakajima, Tomoyuki Ichikawa, Tomoko Utsumi, Koichi Sakata, Hideki Sugiura, Shigeru Emoto, Junichi Awamura, Masami Tomita, Takahiro Honda, Shinichiro Yagi, Tomomi Suzuki, Hiroshi Yamada, Toshiki Nanya, Hiroto Higuchi, Fumihiro Sasaki, Naohito Shimota