Patents by Inventor Toshio Honjo

Toshio Honjo 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: 5965317
    Abstract: A method for regenerating a carrier coated with a silicone resin or a resin containing a silane coupling agent in an electrophotographic developer comprising the carrier and a toner, which comprises separating the developer into the carrier and the toner, immersing the separated carrier in an aqueous alkali solution, and stirring the mixture to remove the toner component adhered to the carrier surface and the coating resin.
    Type: Grant
    Filed: January 6, 1999
    Date of Patent: October 12, 1999
    Assignee: Powdertech Co., Ltd.
    Inventors: Yuji Sato, Tsuyoshi Itagoshi, Toshio Honjo
  • Patent number: 5595850
    Abstract: A ferrite carrier for electrophotographic developers which comprises a Mn-Mg ferrite having the general formula(MnO).sub.x (MgO).sub.y (Fe.sub.2 O.sub.3).sub.zwherein x+y+z=100 mol % and SrO is substituted for a part of MnO, MgO and/or Fe.sub.2 O.sub.3.
    Type: Grant
    Filed: June 28, 1995
    Date of Patent: January 21, 1997
    Assignee: Powdertech Co., Ltd.
    Inventors: Toshio Honjo, Yuji Sato, Kanao Kayamoto, Masahiro Ogata, Hiromichi Kobayashi
  • Patent number: 5518849
    Abstract: This invention provides a ferrite carrier for an electrophotographic developer characterized in that a core material is ferrite particle composed of 17.0 to 29.0 mol % of Li.sub.2 O and 71.0 to 83.0 mol % of Fe.sub.2 O.sub.3, exhibits a resistance of 2.5.times.10.sup.8 to 2.5.times.10.sup.9 .OMEGA. when a voltage of 250 V is applied, satisfies the relationship: a.sub.1 -a.sub.2 .ltoreq.1.5 when the resistance (R.sub.1) of the ferrite particle exhibited when a voltage of 250 V is applied thereto is taken as a.sub.1 .times.10.sup.b .OMEGA. and the resistance (R.sub.2) thereof exhibited when a voltage of 1000 V is applied thereto is taken as a.sub.2 .times.10.sup.b .OMEGA. (with the proviso that 1.0.ltoreq.a.sub.1 <10, 0.1.ltoreq.a.sub.2, and b is an integer of 6 to 9), and the carrier prepared by coating the ferrite particle with a resin exhibits a resistance of 1.0.times.10.sup.9 to 1.0.times.10.sup.15 .OMEGA. when a voltage 250 V is applied thereto, and has a true specific gravity of 4.70 or below.
    Type: Grant
    Filed: December 9, 1994
    Date of Patent: May 21, 1996
    Assignee: Powdertech Co., Ltd.
    Inventors: Yuji Sato, Masahiro Ogata, Kouichi Shimizu, Norio Takei, Toshio Honjo
  • Patent number: 5491042
    Abstract: This invention provides a method for manufacturing a resin-coated carrier for an electrophotographic developer comprising the steps of coating the surface of a carrier core which is a dielectric material, with a resin which is also a dielectric material and then baking the thus obtained resin coated carrier core by means of microwave heating under the conditions that a thickness of the resin-coated carrier layer to be baked is in the range of from 5 to 25 mm, the number of revolution of agitating blade for agitating the microwave is in the range of from 20 to 40 rpm and an irradiation time is in the range of from 30 seconds to 10 minutes, to obtain the resin-coated carrier. The resin-coated carriers are characterized by having an excellent durability, excellent resistance to the environment, as well as excellent producibility and economy.
    Type: Grant
    Filed: July 29, 1994
    Date of Patent: February 13, 1996
    Assignee: Powdertech Co., Ltd.
    Inventors: Yuji Sato, Toshiyuki Fukumoto, Yoshifumi Imamura, Toshio Honjo
  • Patent number: 5466552
    Abstract: A ferrite carrier for electrophotographic developers which comprises a lithium-based ferrite having the general formula(Li.sub.2 O).sub.x (Fe.sub.2 O.sub.3).sub.100-xwherein x is not more than 16.7 mole % and a part of Li.sub.2 O and/or Fe.sub.2 O.sub.3 is substituted with at least one member selected from the group consisting of alkaline earth metal oxides.
    Type: Grant
    Filed: August 19, 1994
    Date of Patent: November 14, 1995
    Assignee: Powdertech Co., Ltd.
    Inventors: Yuji Sato, Toshio Honjo, Kanao Kayamoto, Masahiro Ogata, Kouichi Shimizu
  • Patent number: 5419994
    Abstract: An iron carrier for an electrophotographic developer, the carrier having a mean particle diameter of 25 to 40 .mu.m, a magnetization of at least 160 emu/g at 3000 Oe, an apparent density of 3.0 to 4.2 g/cm.sup.3, a percentage sphericity of at least 80%, and a specific surface area of at least 350 cm.sup.2 /g as determined by an air permeation method; a process for preparing the carrier by a plasma method; and an electrophotographic developer comprising the carrier.
    Type: Grant
    Filed: September 3, 1992
    Date of Patent: May 30, 1995
    Assignee: Powdertech Co., Ltd.
    Inventors: Toshio Honjo, Yuji Sato, Kanao Kayamoto, Masahiro Ogata
  • Patent number: 5204204
    Abstract: This invention relates to a carrier for developing electrostatic latent images comprising;carrier core particles having specified physical properties such as mean particle size, a bulk density, ratio of small particles, surface area index and the like, andresin-coating layers formed of specified components at specified content by a sintering process so that the layer resin may have specified physical properties such as ratio of integrated intensity and the like.
    Type: Grant
    Filed: November 27, 1991
    Date of Patent: April 20, 1993
    Assignees: Minolta Camera Kabushiki Kaisha, Powdertech Co., Ltd.
    Inventors: Yuji Shintani, Etsuaki Urano, Osamu Doi, Shinobu Nakasawa, Ichiro Demizu, Miyoko Ito, Kazuhiro Itadaki, Nobutaka Torii, Yukio Tanigami, Toshio Honjo, Yuji Sato, Toshiyuki Fukumoto
  • Patent number: 4977054
    Abstract: A developer for electrostatic photography comprises toner and carrier coated with a composition comprising a silicone resin having (II) and (II') and at least one compound represented by following formula (III), (IV) or (V): ##STR1##
    Type: Grant
    Filed: July 5, 1989
    Date of Patent: December 11, 1990
    Assignees: Kao Corporation, Nippon Iron Powder Co. Ltd.
    Inventors: Toshio Honjo, Yuji Sato, Yoshihiro Fukushima, Masayoshi Nawa, Shinichiro Yasuda
  • Patent number: 4871639
    Abstract: A carrier for developer is disclosed, which is produced by a process including the steps of mixing and heating a carrier material containing a binder resin and a magnetic powder and essentially free of solvent to obtain a molten dispersion of the magnetic powder in the resin; spraying the molten dispersion into droplets; and cooling the droplets to solidify the droplets into carrier particles. The carrier has excellent sphericality, high surface smoothness, and long life when used as a component of a two-component type developer in electrophotography.
    Type: Grant
    Filed: June 17, 1987
    Date of Patent: October 3, 1989
    Assignees: Fuji Xerox Co., Ltd., Nippon Iron Powder Co., Ltd.
    Inventors: Takayoshi Aoki, Ikutaroh Nagatsuka, Masayuki Takeda, Toshio Honjo, Kazuhiro Itoh, Kenji Uchida
  • Patent number: 4861694
    Abstract: A process for producing carriers for a developer is disclosed, which comprises mixing and heating a carrier material containing a binder resin and a magnetic powder, and essentially free of solvent, to obtain a molten dispersion of the magnetic powder in the binder resin; spraying the molten dispersion into liquid droplets; and cooling the droplets to solidify the droplets into carrier particles. The process eliminates the use of solvents and produces carrier particles of superior toughness, surface smoothness, and sphericality.
    Type: Grant
    Filed: December 16, 1988
    Date of Patent: August 29, 1989
    Assignees: Fuji Xerox Co., Ltd., Nippon Iron Powder Co., Ltd.
    Inventors: Takayoshi Aoki, Masayuki Takeda, Ikutaroh Nagatsuka, Toshio Honjo, Kazuhiro Itoh, Kenji Uchida
  • Patent number: 4598034
    Abstract: A carriers for electrophotographic development which comprises essentially a disintegrated powder of granules consisting essentially of the compound represented by the formula(MO).sub.X (Fe.sub.2 O.sub.3).sub.Yin which M is at least one metal selected from the group consisting of Li, Zn, Cd, Cu, Co, and Mg, and X (mol)/Y (mol).ltoreq.0.85.
    Type: Grant
    Filed: January 7, 1985
    Date of Patent: July 1, 1986
    Assignee: Nippon Iron Powder Co., Ltd.
    Inventors: Toshio Honjo, Yukio Seki