Patents by Inventor Hiroyuki Hirakawa

Hiroyuki Hirakawa 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: 7515851
    Abstract: Provided are an electron emitter continuously emitting electrons stably even in the atmosphere, a charger using the electron emitter, and a charging method using the charger. The electron emitter includes a electron emitting element consisting of a first electrode, a second electrode, and a semiconductor layer formed therebetween, and a power supply for alternately applying a positive voltage enabling electron emission and a negative voltage having a polarity opposite to the positive voltage. At least a part of the surface on the first electrode side of the semiconductor layer is formed of a porous semiconductor layer. Electrons captured in the porous semiconductor layer in the course of electron emission with application of a positive voltage disturb electron emission from the electron emitting element. Such electrons, however, are removed by application of a negative voltage.
    Type: Grant
    Filed: April 28, 2004
    Date of Patent: April 7, 2009
    Assignees: Sharp Kabushiki Kaisha, Nobuyoshi Koshida
    Inventors: Hiroyuki Hirakawa, Tadashi Iwamatsu, Nobuyoshi Koshida
  • Publication number: 20090047594
    Abstract: A developer according to the present invention is arranged such that the composition of particulate metal oxide added as an external additive to a toner surface and the composition of particulate metal oxide added to a resin layer covering a carrier surface are identical to each other, so that the amount of frictional charge that is generated between the toner and the external additive is made larger than the amount of frictional charge that is generated between the external additive and the carrier surface. With this, the external additive is prevented from migrating from the toner surface onto the carrier surface. This makes it possible to prevent the external additive from migrating from the toner surface onto the carrier surface, and thereby to remedy (i) defects in charge and fluidity and (ii) secondary failures, i.e., defects in development that are caused by deterioration in performance of the developer due to the defects in charge and fluidity.
    Type: Application
    Filed: January 11, 2008
    Publication date: February 19, 2009
    Applicant: Sharp Kabushiki Kaisha
    Inventor: Hiroyuki Hirakawa
  • Patent number: 7477442
    Abstract: A large number of holes are formed in a two-layered porous film sandwiched between a lower substrate and an upper substrate and filled with a light transmitting liquid and fine particles. When a voltage is applied between an upper electrode and a lower electrode, migration of the fine particles, takes place based on electrophoresis. White color is displayed when the fine particles are located on an upper transparent porous film side and black color is displayed when the fine particles are located on a lower black porous film side. Color display is also possible by periodically repeating three primary colors of RGB in the lower layer porous film or arranging a color filter on the transparent upper substrate. Bubbles-containing fine particles or bubbles themselves may be employed in place of the fine particles.
    Type: Grant
    Filed: January 21, 2004
    Date of Patent: January 13, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tadashi Iwamatsu, Hiroyuki Hirakawa, Nobuyuki Azuma, Yoshinori Mutou
  • Publication number: 20080299471
    Abstract: A carrier of the present invention is used in a developer including a toner which includes at least a binder resin and an organic colorant, and the carrier has a core and a coating formed on the surface of the core, the coating including (i) a charge control agent for controlling a charge whose polarity is the same as a polarity of a charge controlled by a charge control agent included in the toner, and (ii) a conductive particles. The use of the carrier of the present invention enables: prevention of decrease in the charging amount of the toner which includes at least a binder resin and an organic colorant; and formation of a stable, high-resolution, high-quality image which has very few image defects such as a photographic fog.
    Type: Application
    Filed: May 28, 2008
    Publication date: December 4, 2008
    Inventors: Takanori Kamoto, Tadashi Iwamatsu, Nobuyuki Yoshioka, Yoshinori Mutoh, Hiroyuki Hirakawa, Takashi Hara
  • Patent number: 7317285
    Abstract: An electron emission device comprising an electron emission element (1) having a lower electrode (2), an upper electrode (5) consisting of a thin film, the surface of the upper electrode (5) being exposed to external space, and a semiconductor layer (4) formed between the lower electrode and the upper electrode, a counter electrode (21) provided to face the upper electrode (5) across the external space, a fine particle charging voltage control unit (22) for applying a voltage that charges fine particles deposited on the surface of the upper electrode (5) to between the upper electrode (5) and the lower electrode (2), and flying voltage control unit (23) for applying a voltage that sends charged fine particles flying from the surface of the upper electrode (5) to between the upper electrode (5) and the counter electrode (21), wherein the fine particle charging voltage control unit is operated to charge deposited fine particles, and the flying voltage control unit is operated to sent charged fine particles flyi
    Type: Grant
    Filed: January 14, 2004
    Date of Patent: January 8, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tadashi Iwamatsu, Hiroyuki Hirakawa
  • Patent number: 7307379
    Abstract: An electron emitting element is of a structure in which a semiconductor layer is formed between an upper electrode and a lower electrode, wherein an organic compound adsorption layer is formed on a semiconductor surface of the semiconductor layer by causing the organic compound to be adsorbed on the semiconductor surface. Herein, the semiconductor layer can be made of silicon or polysilicon and partly or as a whole porous. The absorbed organic compound can be a non-cyclic hydrocarbon, a compound obtained by coupling at least an aldehyde group to a non-cyclic hydrocarbon, or a non-cyclic hydrocarbon having an unsaturated bond. As a result, there can be provided an electron emitting element capable of stably operating in the atmosphere or in a low vacuum even when being operated in the atmosphere or in the low vacuum and an imaging device using the electron emitting element.
    Type: Grant
    Filed: April 13, 2004
    Date of Patent: December 11, 2007
    Assignees: Sharp Kabushiki Kaisha
    Inventors: Tadashi Iwamatsu, Hiroyuki Hirakawa, Nobuyoshi Koshida
  • Publication number: 20070265427
    Abstract: A liquid thermosetting epoxy resin composition contains a base resin in combination with a curing agent and a curing accelerator or with a curing catalyst. The base resin includes a cycloaliphatic epoxy compound having at least one alicyclic skeleton and two or more epoxy groups per molecule, and a polyol oligomer having two or more terminal hydroxyl groups. An optical semiconductor device includes an optical semiconductor element sealed by using the liquid thermosetting epoxy resin composition. The composition yields a cured resinous product which is free from curing failure, is optically homogenous, has a low elastic modulus in bending, a high bending strength, a high glass transition temperature, a high optical transparency and is useful for optical semiconductors.
    Type: Application
    Filed: December 9, 2005
    Publication date: November 15, 2007
    Inventors: Hideyuki Takai, Hiroyuki Hirakawa
  • Publication number: 20070231236
    Abstract: A method of producing halosilane of the present invention includes the steps of (1) subjecting used slurry 1to a primary centrifugal separation to recover a solid fraction 3b predominantly composed of abrasive grains, the used slurry comprising slurry and silicon particles mixed in the slurry, the slurry comprising the abrasive grains and a water-soluble dispersion medium for dispersing the abrasive grains therein, (2) subjecting a liquid fraction 3a obtained by the primary centrifugal separation to a secondary centrifugal separation to separate into a liquid fraction 5a predominantly composed of the dispersion medium and remaining sludge 5b, (3) distilling the liquid fraction 5a obtained by the secondary centrifugal separation to obtain a solid fraction 7b, followed by performing crushing and organic residue removal with regards to the solid fraction 7b, and (4) reacting the resultant solid fraction with a halogenating agent, and rectifying a product obtained by the reaction to recover halosilane.
    Type: Application
    Filed: May 12, 2005
    Publication date: October 4, 2007
    Inventors: Kimihiko Kajimoto, Tomoyuki Oba, Hiroyuki Hirakawa
  • Publication number: 20070206270
    Abstract: A large number of holes are formed in a two-layered porous film sandwiched between a lower substrate and an upper substrate and filled with a light transmitting liquid and fine particles. When a voltage is applied between an upper electrode and a lower electrode, migration of the fine particles, takes place based on electrophoresis. White color is displayed when the fine particles are located on an upper transparent porous film side and black color is displayed when the fine particles are located on a lower black porous film side. Color display is also possible by periodically repeating three primary colors of RGB in the lower layer porous film or arranging a color filter on the transparent upper substrate. Bubbles-containing fine particles or bubbles themselves may be employed in place of the fine particles.
    Type: Application
    Filed: January 21, 2004
    Publication date: September 6, 2007
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Tadashi Iwamatsu, Hiroyuki Hirakawa, Nobuyuki Azuma, Yoshinori Mutou
  • Publication number: 20070159660
    Abstract: Toner transfer means is provided which is installed between a first stirring chamber and a second stirring chamber, which are provided respectively on an upstream side and a downstream side of a flow of toner which is stirred into a developer and charged in a process of transferring the toner from a toner retaining chamber to a photoreceptor drum, the toner transfer means controlling a toner density by transferring the toner from the first stirring chamber to the second stirring chamber, in order that: a weight percentage of the toner relative to a developer in the first stirring chamber is equal to or less than a first threshold value governing time involved in uniformly charging the toner; and a weight percentage of the toner relative to the developer in the second stirring chamber is (i) greater than the first threshold value and (ii) equal to or less than a second threshold value necessary for eliminating uncharged toner in the second stirring chamber.
    Type: Application
    Filed: June 21, 2006
    Publication date: July 12, 2007
    Applicant: Sharp Kabushiki Kaisha
    Inventor: Hiroyuki Hirakawa
  • Publication number: 20060291905
    Abstract: Provided are an electron emitter continuously emitting electrons stably even in the atmosphere, a charger using the electron emitter, and a charging method using the charger. The electron emitter includes a electron emitting element consisting of a first electrode, a second electrode, and a semiconductor layer formed therebetween, and a power supply for alternately applying a positive voltage enabling electron emission and a negative voltage having a polarity opposite to the positive voltage. At least a part of the surface on the first electrode side of the semiconductor layer is formed of a porous semiconductor layer. Electrons captured in the porous semiconductor layer in the course of electron emission with application of a positive voltage disturb electron emission from the electron emitting element. Such electrons, however, are removed by application of a negative voltage.
    Type: Application
    Filed: April 28, 2004
    Publication date: December 28, 2006
    Inventors: Hiroyuki Hirakawa, Tadashi Iwamatsu, Nobuyoshi Koshida
  • Publication number: 20060186786
    Abstract: An electron emitting element is of a structure in which a semiconductor layer is formed between an upper electrode and a lower electrode, wherein an organic compound adsorption layer is formed on a semiconductor surface of the semiconductor layer by causing the organic compound to be adsorbed on the semiconductor surface. Herein, the semiconductor layer can be made of silicon or polysilicon and partly or as a whole porous. The absorbed organic compound can be a non-cyclic hydrocarbon, a compound obtained by coupling at least an aldehyde group to a non-cyclic hydrocarbon, or a non-cyclic hydrocarbon having an unsaturated bond. As a result, there can be provided an electron emitting element capable of stably operating in the atmosphere or in a low vacuum even when being operated in the atmosphere or in the low vacuum and an imaging device using the electron emitting element.
    Type: Application
    Filed: April 13, 2004
    Publication date: August 24, 2006
    Inventors: Tadashi Iwamatsu, Hiroyuki Hirakawa, Nobuyoshi Koshida
  • Publication number: 20060152166
    Abstract: An electron emission device comprising an electron emission element (1) having a lower electrode (2), an upper electrode (5) consisting of a thin film, the surface of the upper electrode (5) being exposed to external space, and a semiconductor layer (4) formed between the lower electrode and the upper electrode, a counter electrode (21) provided to face the upper electrode (5) across the external space, a fine particle charging voltage control unit (22) for applying a voltage that charges fine particles deposited on the surface of the upper electrode (5) to between the upper electrode (5) and the lower electrode (2), and flying voltage control unit (23) for applying a voltage that sends charged fine particles flying from the surface of the upper electrode (5) to between the upper electrode (5) and the counter electrode (21), wherein the fine particle charging voltage control unit is operated to charge deposited fine particles, and the flying voltage control unit is operated to sent charged fine particles flyi
    Type: Application
    Filed: January 14, 2004
    Publication date: July 13, 2006
    Inventors: Tadashi Iwamatsu, Hiroyuki Hirakawa
  • Patent number: 6873813
    Abstract: The increasing ratio of development density to increase in potential difference between a photoreceptor and a development roller differs between the region where the potential difference is small and the region where the potential difference is large. The increasing ratio of development density at the region where the potential difference is small is smaller than the increasing ratio of development density at the region where the potential difference is large. Development is conducted under the developing characteristics in which the upper limit of the development density at the region where the increasing ratio of development density is small is at least 0.3.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: March 29, 2005
    Assignee: Sharp Kabuskiki Kaisha
    Inventors: Kazuhiko Furukawa, Tadashi Iwamatsu, Hiroyuki Hirakawa, Tetsuro Toyoshima
  • Publication number: 20050052687
    Abstract: An image processing device includes a first input-output unit connected to a first external bus, a second input-output unit connected to a second external bus, an internal bus connecting the first input-output unit and the second input-output unit and an image processing unit connected to the internal bus. The internal bus operates as a through path for passing image data without intervening with the image processing unit between the first input-output unit and the second input-output unit. After the image processing unit executes an image processing operation on image data input from one of the first input-output unit and the second input-output unit, the image processing unit outputs processed image data from another one of the first input-output unit and the second input-output unit.
    Type: Application
    Filed: July 1, 2004
    Publication date: March 10, 2005
    Inventor: Hiroyuki Hirakawa
  • Publication number: 20040109707
    Abstract: The increasing ratio of development density to increase in potential difference between a photoreceptor and a development roller differs between the region where the potential difference is small and the region where the potential difference is large. The increasing ratio of development density at the region where the potential difference is small is smaller than the increasing ratio of development density at the region where the potential difference is large. Development is conducted under the developing characteristics in which the upper limit of the development density at the region where the increasing ratio of development density is small is at least 0.3.
    Type: Application
    Filed: December 3, 2003
    Publication date: June 10, 2004
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Kazuhiko Furukawa, Tadashi Iwamatsu, Hiroyuki Hirakawa, Tetsuro Toyoshima
  • Patent number: 6681091
    Abstract: The increasing ratio of development density to increase in potential difference between a photoreceptor and a development roller differs between the region where the potential difference is small and the region where the potential difference is large. The increasing ratio of development density at the region where the potential difference is small is smaller than the increasing ratio of development density at the region where the potential difference is large. Development is conducted under the developing characteristics in which the upper limit of the development density at the region where the increasing ratio of development density is small is at least 0.3.
    Type: Grant
    Filed: May 10, 2002
    Date of Patent: January 20, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kazuhiko Furukawa, Tadashi Iwamatsu, Hiroyuki Hirakawa, Tetsuro Toyoshima
  • Patent number: 6622000
    Abstract: A developing apparatus includes a developer carrier carrying a developer on its surface, a developer regulating member regulating layer thickness of the developer, a charge amount control member controlling the charge amount of the developer and a charge supplying apparatus downstream of the charge amount control member. The charge amount control member controls the amount of charges of the developer, by causing the developer fly over the developer carrier, using an AC voltage applied between the developer carrier and the charge amount control member, and by applying the electric charges generated by gas electrolytic dissociation caused by the AC voltage. By this structure, a developing apparatus can be provided which can improve stability of development and image quality, without necessitating delicate arrangement of the component materials of the developer.
    Type: Grant
    Filed: July 26, 2001
    Date of Patent: September 16, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kazuhiko Furukawa, Hiroyuki Hirakawa, Shigeru Nishio
  • Publication number: 20030063925
    Abstract: The increasing ratio of development density to increase in potential difference between a photoreceptor and a development roller differs between the region where the potential difference is small and the region where the potential difference is large. The increasing ratio of development density at the region where the potential difference is small is smaller than the increasing ratio of development density at the region where the potential difference is large. Development is conducted under the developing characteristics in which the upper limit of the development density at the region where the increasing ratio of development density is small is at least 0.3.
    Type: Application
    Filed: May 10, 2002
    Publication date: April 3, 2003
    Inventors: Kazuhiko Furukawa, Tadashi Iwamatsu, Hiroyuki Hirakawa, Tetsuro Toyoshima
  • Publication number: 20020012552
    Abstract: A developing apparatus includes a developer carrier carrying a developer on its surface, a developer regulating member regulating layer thickness of the developer, and a charge amount control member controlling the charge amount of the developer. The charge amount control member controls the amount of charges of the developer, by causing the developer fly over the developer carrier, using an AC voltage applied between the developer carrier and the charge amount control member, and by applying the electric charges generated by gas electrolytic dissociation caused by the AC voltage. By this structure, a developing apparatus can be provided which can improve stability of development and image quality, without necessitating delicate arrangement of the component materials of the developer.
    Type: Application
    Filed: July 26, 2001
    Publication date: January 31, 2002
    Inventors: Kazuhiko Furukawa, Hiroyuki Hirakawa, Shigeru Nishio