Patents by Inventor Takafumi Nagai

Takafumi Nagai 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: 8948658
    Abstract: A developing device comprises a first and a second developer conveyance path. A first conveyance member is provided in the first developer conveyance path in a freely rotatable manner and has a helical blade. A developing roller supplies the developer in the first developer conveyance path to a photoconductor drum. A developer collection path guides two-component developer left on a surface of the developing roller from the first developer conveyance path. A developer surface adjustment window comprises a predetermined level for allowing excess developer exceeding the level of the window to be guided from the first developer conveyance path to the developer collection path.
    Type: Grant
    Filed: January 24, 2012
    Date of Patent: February 3, 2015
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8831483
    Abstract: In a developing device including a developer tank and a developing roller, an internal space of the developer tank is divided into a first conveying path, a second conveying path, a first communication path and a second communication path, by a partition wall. A first developer conveying section which conveys a developer in the developer tank in a conveying direction X is disposed in the first conveying path. A second developer conveying section which conveys the developer in the developer tank in a conveying direction Y is disposed in the second conveying path. The first developer conveying section includes a plurality of inner spiral blade pieces, a rotation tube, an upstream spiral blade, a downstream spiral blade, support members, and a first gear.
    Type: Grant
    Filed: February 23, 2012
    Date of Patent: September 9, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8744319
    Abstract: A developing device has a developer tank for containing a two-component developer; a partition; a first and a second developer conveyance path for conveying the developer in pairs; a first conveyance member for conveying the developer in one direction, which has a first rotation axis, a first helical blade fixed to the first rotation axis, and a first passive gear provided to an end of the first rotation axis; a second conveyance member for conveying the developer in one direction, which has a second rotation axis, a second helical blade fixed to the second rotation axis, and a second passive gear provided to an end of the second rotation axis; a first communicating path; a second communicating path; a developing roller; and a rotation axis bending prevention belt provided so as to bridge the first and the second rotation axis outside the developer tank.
    Type: Grant
    Filed: August 22, 2012
    Date of Patent: June 3, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroyoshi Maehara, Takafumi Nagai
  • Patent number: 8744320
    Abstract: In a developing device including a developer tank and a developing roller, an internal space of the developer tank is divided by a partition wall into a first conveying path, a second conveying path, a communication path and a pumping path. In the pumping path, there is disposed a developer pumping section including a pumping spiral blade, a pumping rotation shaft member, and a pumping gear. A developer in the pumping path is pumped up by the developer pumping section, so that a part of the developer is moved to a side of the first conveying path while another part of the developer is moved to a side of the second conveying path.
    Type: Grant
    Filed: December 14, 2011
    Date of Patent: June 3, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8731443
    Abstract: A developing device has a first and a second developer conveyance path configured to convey and circulate the two-component developer; a first and a second conveyance member each having a helical blade for conveying the developer in one direction; a first communicating path for guiding the developer in the first developer conveyance path to the second developer conveyance path; a second communicating path. The second developer conveyance path includes a second upstream side end section having a bottom in a conical shape having an inner diameter conically increasing. The helical blade of the second conveyance member has a second conical helix portion having an outer diameter conically increasing along an inner wall surface of the bottom of the second upstream side end section. The bottom of the second upstream side end section is at a level lower than a bottom of the first developer conveyance path.
    Type: Grant
    Filed: April 11, 2012
    Date of Patent: May 20, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8688013
    Abstract: A developing device comprises a first and a second developer conveyance path; a first conveyance member; a second conveyance member; and, a developing roller. A developer collection path guides the developer left on a surface of the developing roller in a direction away from the first developer conveyance path. A third conveyance member is provided in a third developer conveyance path. A toner supply port supplies new toner to the third developer conveyance path. A developer drawing and conveyance path guides the developer supplied with the new toner to the second developer conveyance path. A developer drawing member is provided in the developer drawing and conveyance path for simultaneously agitating and conveying the developer.
    Type: Grant
    Filed: January 24, 2012
    Date of Patent: April 1, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8682227
    Abstract: A toner discharging device has a toner containing section, a toner discharging member, and a toner discharging section. The toner discharging section has a toner discharge port formed by opening a vertically lower part of the cylindrical wall. The toner discharging member has a rotation axis; a toner discharge plate fixed to the rotation axis at a position facing the discharge port in the vicinity of one end of the discharging section and vertically above the discharge port; an elastic helical blade being fixed, to the discharge plate and being stretchable in a direction of the rotation axis; and a helical blade section having a helical blade fixed to the rotation axis over an area in the vicinity of another end of the discharging section and an area within the containing section where the discharge plate and the elastic helical blade are not formed.
    Type: Grant
    Filed: June 29, 2012
    Date of Patent: March 25, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Toshihide Ohgoshi, Takafumi Nagai
  • Patent number: 8682226
    Abstract: A development device mounted on an electrophotographic image forming apparatus including a photoconductive drum in which an electrostatic latent image is formed on a surface thereof, the development device comprising: a developer tank; a development roller that is provided in the developer tank; first and second developer conveying paths; and first and second developer conveying spiral members that conveying the developer in the circulating manner in the first and second developer conveying paths, wherein at least one of the first and second developer conveying spiral members further includes an end blade that is provided at one end of the rotary shaft, the end blade includes: a spiral blade portion that is fixed to the circumferential surface of the rotary shaft; and a circumferential agitating plate portion that is fixed to a circumferential portion of the spiral blade portion.
    Type: Grant
    Filed: August 15, 2011
    Date of Patent: March 25, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8660466
    Abstract: A development device comprising a developer conveying member and a developer raking member that are rotatably disposed in the developer conveyance path to conveying and agitating the developer in the developer conveyance paths, wherein the developer conveyance path includes first and second developer conveyance paths and first and second communication paths that communicating the first and second developer conveyance paths on both sides, the developer conveying member includes first and second developer conveying members that are disposed in the first and second developer conveyance paths, the developer raking member is disposed in at least one of the first and second communication paths.
    Type: Grant
    Filed: June 14, 2011
    Date of Patent: February 25, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8594538
    Abstract: A developing device includes a developer tank and a developing roller. An internal space of the developer tank is divided into a first conveying path, a second conveying path, a first communication path, and a second communication path by a partition wall. In the first conveying path, there is disposed a first developer conveying section that conveys the developer within the developer tank in a conveying direction X. In the second conveying path, there is disposed a second developer conveying section that conveys the developer within the developer tank in a conveying direction Y. The first developer conveying section includes an inner spiral blade, an outer spiral blade, an upstream spiral blade, a rotation tube, a delivery portion, support members, and a first gear. The rotation tube has an admission port portion and a discharge port portion.
    Type: Grant
    Filed: January 20, 2012
    Date of Patent: November 26, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8588656
    Abstract: A developer tank of a developing device is partitioned into a first conveyance path, a second conveyance path, a first communicating path and a second communicating path with a partition. A first developer conveying member that conveys a developer in a first developer conveying direction is provided in the first conveyance path. A second developer conveying member that conveys the developer in a second developer conveying direction is provided in the second conveyance path. In the first developer conveying member, a double spiral blade is provided on a downstream side in the first developer conveying direction from a first conveying blade of the first developer conveying member, the double spiral blade including an inner spiral blade that conveys the developer in a first direction and an outer spiral blade that conveys the developer in a second direction.
    Type: Grant
    Filed: May 18, 2011
    Date of Patent: November 19, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8588657
    Abstract: In a developing device including a developer tank and a developing roller, an internal space of the developer tank is partitioned by a partition into a first conveying path, a second conveying path, a first communication path, and a second communication path. A first developer conveying section that conveys the developer in the developer tank in a first conveying direction X is disposed in the first conveying path. A second developer conveying section that conveys the developer in the developer tank in a second conveying direction Y is disposed in the second conveying path. The first developer conveying section includes a first spiral blade, and a rotation tube.
    Type: Grant
    Filed: August 19, 2011
    Date of Patent: November 19, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8554115
    Abstract: A developing device includes a developer tank and a developing roller. An internal space of the developer tank is divided into an upper conveying path, a lower conveying path, a communication path, a main pumping conveying path section, and a developer supply path, by a partition wall. A developer pumping conveying section conveys a developer inside the main pumping conveying path section in a conveyance direction Z, and includes an inner spiral blade, a rotational tube, a first outer spiral blade, a second outer spiral blade, a pumping rotation shaft member, and a pumping gear. An attracting magnet is located in a position horizontally spaced from the rotational tube.
    Type: Grant
    Filed: December 5, 2011
    Date of Patent: October 8, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8526863
    Abstract: A toner discharge mechanism which is attached to a toner cartridge includes an auger screw for conveying and discharging a toner stored in the toner cartridge, the auger screw having an end portion downstream thereof, the end portion forming a taper portion having a predetermined length and an outer diameter diminishing toward a tip thereof; a cover member for covering the taper portion, the cover member having a conical inner wall configured to correspond to a taper shape of the taper portion; and a toner discharge outlet formed on the cover member.
    Type: Grant
    Filed: February 25, 2011
    Date of Patent: September 3, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8521069
    Abstract: A developing device to be installed in an electrophotographic image forming apparatus including a photoconductor drum that is to have an electrostatic latent image formed on a surface thereof, the developing device comprising: a developer vessel; a developing roller that is disposed in the developer vessel; first and second developer conveying passages; and first and second developer conveying helical members circulatory conveys the developer in the first and second developer conveying passages, wherein at least one of the first and second developer conveying helical members includes an end blade at one end at a downstream side in a conveying direction, wherein the end blade includes a circumferential-direction agitating blade portion whose radial projecting size gradually increases toward the downstream side in the conveying direction; and a helical blade portion integrally wound around an outer periphery of the circumferential-direction agitating blade portion.
    Type: Grant
    Filed: May 20, 2011
    Date of Patent: August 27, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8488998
    Abstract: A developing device comprising: a developer vessel that accommodates a developer containing a toner and a carrier; a toner supply port; a developing roller; a developer conveying passage; a developer conveying helical member; and a developer scooping member, wherein the developer conveying passage includes a first developer conveying passage and the a second developer conveying passage being defined by a partitioning plate, and a first communicating path and a second communicating path that establish a communication between the first and second developer conveying passage, the developer conveying helical member includes a first developer conveying helical member disposed in the first developer conveying passage, and a second developer conveying helical member disposed in the second developer conveying passage, the developer scooping member includes a first developer scooping member disposed near the first communicating path to send the developer in the first developer conveying passage into the second develop
    Type: Grant
    Filed: January 18, 2011
    Date of Patent: July 16, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8488999
    Abstract: A developing device that is capable of securing an amount of developer that can be stored in a developer tank while suppressing the bending of a developer conveying section, as well as an image forming apparatus are provided. In a developer tank of a developing device, there is provided a first developer conveying section that includes a first rotation shaft member having a columnar shape in which grooves extending in an axial line direction are formed, and a first spiral blade that is spirally wound around the first rotation shaft member and conveys the developer by rotation around the axial line of the first rotation shaft member.
    Type: Grant
    Filed: September 13, 2011
    Date of Patent: July 16, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8472845
    Abstract: A developing device comprising: a developer tank housing a developer including a toner and a carrier; a toner replenishment port; a developing roller; a first developer conveying path and a second developer conveying path; a conducting plate for peeling a recovery developer on a surface of the developing roller after the toner is supplied to a photosensitive drum from the surface of the developing roller so as to guide the recovery developer to the first developer conveying path; and first and second developer conveying members arranged on the first and second developer conveying paths, wherein the first developer conveying member has a cylindrical hollow rotating shaft with opened both ends that is rotatably provided to the first developer conveying path, and divides the first developer conveying path into an external first developer conveying path and an internal first developer conveying path, an external spiral blade fixed to an outer periphery of the hollow rotating shaft, and an internal spiral blade fi
    Type: Grant
    Filed: July 8, 2011
    Date of Patent: June 25, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai
  • Patent number: 8452215
    Abstract: A developing device and an image forming apparatus which suppress unevenness of image density are provided. A developing device includes a developer tank storing a developer, a first conveying member and a second conveying member conveying the developer, and a developing roller bearing the developer thereon. In the developing device, the first conveying member is constituted by a first rotating shaft and a plurality of first conveying blades provided along a first imaginary spiral surrounding the outer periphery of the first rotating shaft and advancing in the axial direction of the first rotating shaft at a predetermined lead angle ?X. The individual first conveying blades are separated from each other in the axial direction and are provided along the portion of less than one cycle of the first imaginary spiral.
    Type: Grant
    Filed: January 21, 2011
    Date of Patent: May 28, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Mihara, Takafumi Nagai
  • Patent number: 8401432
    Abstract: A developing device includes a developing tank for containing a powder developer, an agitating member disposed in the developing tank to agitate the powder developer; and a cooling tank attached to the developing tank. The cooling tank contains an endothermic material to absorb heat from the powder developer.
    Type: Grant
    Filed: November 3, 2010
    Date of Patent: March 19, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Shigeki Hayashi, Takafumi Nagai