Patents by Inventor Akihiro Kotsugai

Akihiro Kotsugai 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: 6696213
    Abstract: A method of developing a latent electrostatic image using a two-component developer system, having a ratio (Vr/Vp) ranges 1.2<(Vr/Vp)<3 where the (Vp) is a linear speed (Vp)[m/sec] of a photosensitive member and the (Vr) is a linear speed (Vr) [m/sec] of a developing sleeve, and applying a biased direct-current (VB) [by volt] wherein; a developing gap(Gp)[cm] as a distance at the nearest point between a photosensitive member and a developing sleeve is less than or equal to 0.6 mm, a ratio(&rgr;p/&rgr;a) satisfies an expression (&rgr;p/&rgr;a)<0.
    Type: Grant
    Filed: March 7, 2002
    Date of Patent: February 24, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Akihiro Kotsugai
  • Publication number: 20030224279
    Abstract: A carrier for use with a toner as a two-component type developer for developing an electrostatic image, comprising spherical magnetic core particles, and a resin layer covering each of said core particles and containing at least two resistance controlling materials having different specific resistances, wherein each of the resistance controlling materials is in the form of particles having a number average particle diameter of no more than {fraction (1/10)} of a number average particle diameter of the toner.
    Type: Application
    Filed: March 21, 2003
    Publication date: December 4, 2003
    Inventors: Akihiro Kotsugai, Kimitoshi Yamaguchi, Naoki Imahashi, Hiroaki Takahashi
  • Patent number: 6653037
    Abstract: A toner for developing latent electrostatic images is provided which contains, in a binder resin, at least a coloring agent formed from a metal material. A saturation magnetization of the toner is 0.01 to 10 emu/g, and a true specific gravity thereof is 1.33 to 1.62 g/m3. Also provided are an electrostatic charge image developer containing the toner for developing latent electrostatic images, an image forming device, and an image forming method using the toner for developing latent electrostatic images.
    Type: Grant
    Filed: November 19, 2001
    Date of Patent: November 25, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Masahide Yamashita, Akihiro Kotsugai, Keiko Shiraishi
  • Publication number: 20030211415
    Abstract: A carrier for an image developer for electrophotography, including core particles, and a coating layer covering each of the core particles, wherein the core particles have a weight average particle diameter of Dv which is 25-45 &mgr;m and a number average particle diameter of Dp which meets with the following condition:
    Type: Application
    Filed: May 23, 2003
    Publication date: November 13, 2003
    Inventors: Kimitoshi Yamaguchi, Akihiro Kotsugai
  • Publication number: 20030143000
    Abstract: A process for developing which includes the step of developing a latent electrostatic image on a latent electrostatic image support by a developing agent supplied on a development sleeve, where the developing agent is supplied with a density of 1.3 g/cm3 to 2.0 g/cm3 at the closest part between the support and the sleeve, the support is contacted with magnetic brushes formed of the developing agent on the sleeve, so that the magnetic brushes have a width of 2 mm or less at a linearly contacting surface, in a direction where the surface rotates and the developing agent contains toners, and carriers having magnetic core particles and resin layers to cover its surface, the carriers have a weight average particle diameter of 25 &mgr;m to 45 &mgr;m, contain 60 wt % or more of the particles having a diameter of less than 44 &mgr;m, and 7 wt % or less of particles having a diameter of less than 22 &mgr;m.
    Type: Application
    Filed: January 10, 2003
    Publication date: July 31, 2003
    Inventors: Hiroaki Takahashi, Kimitoshi Yamaguchi, Naoki Imahashi, Akihiro Kotsugai
  • Patent number: 6599672
    Abstract: A carrier for an image developer for electrophotography, including core particles, and a coating layer covering each of the core particles, wherein the core particles have a weight average particle diameter of Dv which is 25-45 &mgr;m and a number average particle diameter of Dp which meets with the following condition: 1≦Dv/Dp≦1.3, wherein the core particles have such a particle size distribution that particles having a particle diameter of less than 44 &mgr;m is at least 70% by weight and particles having a particle diameter of less than 22 &mgr;m is not more than 7% by weight.
    Type: Grant
    Filed: August 22, 2002
    Date of Patent: July 29, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Kimitoshi Yamaguchi, Akihiro Kotsugai
  • Publication number: 20030096183
    Abstract: A color toner composition including at least toner particles including at least a binder resin; a colorant and a release agent dispersed in the binder resin; and a titania as an external additive, wherein the colorant has an average dispersion particle diameter not greater than 0.5 &mgr;m; the release agent and the binder resin are insoluble to each other; the toner particles satisfy the relationship: 0.05≦Dw/D4≦0.4, wherein Dw represents an average dispersion particle diameter of the release agent and D4 represents a weight-average particle diameter of the toner particles; and the titania has a segregation rate of from 0.5 to 5%.
    Type: Application
    Filed: February 22, 2002
    Publication date: May 22, 2003
    Inventors: Kohki Katoh, Masanori Suzuki, Yohichiro Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Keiko Shiraishi
  • Publication number: 20030054279
    Abstract: A carrier for electrophotographic developer essentially consisting of a core material of magnetic particles and thereon provided a resinous coating layer, wherein a weight-average particle-diameter(Dw) of the carrier ranges from 25 to 45 &mgr;m, the content of particles having diameter less than 44 &mgr;m is more than or equal to 75% by weight, the content of particles having diameter more than or equal to 62 &mgr;m is less than one percent by weight, the content of particles having diameter less than 22 &mgr;m is less than or equal to 7.0% by weight, the magnetic moment of the carrier at 1 kilo Oe of magnetic field is more than or equal to 76 emu/g. The carrier shows high optical density of image with no smearing of background area, good reproducibility in developing of small dots in image with no carrier deposition.
    Type: Application
    Filed: May 1, 2002
    Publication date: March 20, 2003
    Inventors: Kimitoshi Yamaguchi, Masahide Yamashita, Akihiro Kotsugai, Hiroaki Takahashi
  • Publication number: 20030044713
    Abstract: A method of developing a latent electrostatic image using a two-component developer system, having a ratio (VrNVp) ranges 1.2<(Vr/Vp)<3 where the (Vp) is a linear speed (Vp) [m/sec] of a photosensitive member and the (Vr) is a linear speed (Vr) [m/sec] of a developing sleeve, and applying a biased direct-current (VB) [by volt] wherein; a developing gap(Gp)[cm] as a distance at the nearest point between a photosensitive member and a developing sleeve is less than or equal to 0.6 mm, a ratio(&rgr;p/&rgr;a) satisfies an expression (&rgr;p/&rgr;a)<0.
    Type: Application
    Filed: March 7, 2002
    Publication date: March 6, 2003
    Inventors: Kimitoshi Yamaguchi, Akihiro Kotsugai
  • Publication number: 20030044709
    Abstract: A carrier for an image developer for electrophotography, including core particles, and a coating layer covering each of the core particles, wherein the core particles have a weight average particle diameter of Dv which is 25-45 &mgr;m and a number average particle diameter of Dp which meets with the following condition:
    Type: Application
    Filed: August 22, 2002
    Publication date: March 6, 2003
    Inventors: Kimitoshi Yamaguchi, Akihiro Kotsugai
  • Patent number: 6489073
    Abstract: Electrostatic latent images are developed with a toner in such a configuration that an electrostatic-latent-image-bearing member is disposed to face a developer-bearing member which bears thereon a developer consisting of a magnetic carrier and a toner by relatively moving the developer-bearing member and the electrostatic-latent-image-bearing member at different velocities, with the development being carried out under conditions represented by formula (1): 0.
    Type: Grant
    Filed: January 12, 2001
    Date of Patent: December 3, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Akihiro Kotsugai, Kimitoshi Yamaguchi, Hiroshi Ikuno
  • Patent number: 6472118
    Abstract: A carrier for an image developer for electrophotography, including core particles, and a coating layer covering each of the core particles, wherein the core particles have a weight average particle diameter of Dv which is 25-45 &mgr;m and a number average particle diameter of Dp which meets with the following condition: 1≦Dv/Dp≦1.3, wherein the core particles have such a particle size distribution that particles having a particle diameter of less than 44 &mgr;m is at least 70% by weight and particles having a particle diameter of less than 22 &mgr;m is not more than 7% by weight.
    Type: Grant
    Filed: November 16, 2000
    Date of Patent: October 29, 2002
    Assignee: Ricoh Company, Ltd
    Inventors: Kimitoshi Yamaguchi, Akihiro Kotsugai
  • Publication number: 20020136975
    Abstract: A toner for developing electrostatic latent images, including a matrix of a first resin selected from polyester resins, polyol resins and mixtures thereof, a plurality of domains of a second resin dispersed in the matrix and containing a wax. The amount of the wax is 2-15% by weight based on the weight of the toner The matrix is substantially free of domains of the second resin having a maximum diameter of greater than 2.0 &mgr;m. A part of the domains containing the wax having a maximum diameter of at least 0.2 &mgr;m constitutes a part of an outer surface of the toner.
    Type: Application
    Filed: November 27, 2001
    Publication date: September 26, 2002
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Kohki Katoh
  • Publication number: 20020132177
    Abstract: A toner for developing latent electrostatic images is provided which contains, in a binder resin, at least a coloring agent formed from a metal material. A saturation magnetization of the toner is 0.01 to 10 emu/g, and a true specific gravity thereof is 1.33 to 1.62 g/m3. Also provided are an electrostatic charge image developer containing the toner for developing latent electrostatic images, an image forming device, and an image forming method using the toner for developing latent electrostatic images.
    Type: Application
    Filed: November 19, 2001
    Publication date: September 19, 2002
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Masahide Yamashita, Akihiro Kotsugai, Keiko Shiraishi
  • Patent number: 6168894
    Abstract: An image forming method including a new toner fixing method and toner therefor, wherein the method includes two rollers in which a toner image on an image supporting material is fixed by heating at a nipped section of the rollers, wherein one of the rollers which is a fixing roller contacting the toner image includes a metal cylinder having a thickness of not more than 1.0 mm, and the fixing pressure of the two rollers is not more than 1.4×105 Pa, and wherein the toner contains resins including two polyester resins, (A) and (B), and the polyester resin (B) includes discrete domains of the polyester resin (A) which has higher glass transition Tg and higher molecular weight than those of the polyester resin (B) and includes a component insoluble in tetrahydrofuran, and wherein the developed image can be fixed at relative low temperature and in wide temperature range, and the fixed image has excellent image quality and preserving property.
    Type: Grant
    Filed: September 13, 1996
    Date of Patent: January 2, 2001
    Assignee: Ricoh Company, Ltd.
    Inventors: Mitsuo Aoki, Hachiro Tosaka, Hiroyuki Fushimi, Masanori Suzuki, Akihiro Kotsugai
  • Patent number: 6010814
    Abstract: An electrophotographic toner composition is disclosed, including toner particles containing a coloring agent, a binder resin and at least two kinds of additives, wherein these additives satisfy the relationship, 4<((.di-elect cons..sub.H -.di-elect cons..sub.L)/0.75+log(f))<16, in which f in Hz corresponds to a 1 kHz frequency used for the present dielectric constant measurements, and .di-elect cons..sub.H and .di-elect cons..sub.L are respectively highest and lowest values of dielectric constants obtained at 1 kHz for the additives.
    Type: Grant
    Filed: October 26, 1998
    Date of Patent: January 4, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Akihiro Kotsugai, Masanori Suzuki
  • Patent number: 6004715
    Abstract: A toner for developing an electrostatic latent image, which includes ground toner particles having physical properties meeting with at least one of the following conditions (a) and (b):(a) the toner particles have an average surface roughness of at least 0.89, the average suface roughness being an average of SF1 of respective toner particles, where SF1 is defined as follows:SF1=Le/Lpwherein Le and Lp represent the length of the minimum envelope line and the peripheral length of each toner particle, respectively;(b) the toner particles have an average shape index SF3 of at least 0.63, the average shape index being a product of the average of SF1 and an average of SF2, where SF1 is as defined above and SF2 is defined as follows:SF2=4S/(P.sup.2 .times..pi.)wherein S and P represent the area and the maximum diameter of each toner particle, respectively.
    Type: Grant
    Filed: June 25, 1996
    Date of Patent: December 21, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Masanori Suzuki, Hachiroh Tosaka, Mituo Aoki, Hiroyuki Fushimi, Akihiro Kotsugai
  • Patent number: 5912100
    Abstract: A toner for developing an electrostatic latent image, including toner particles having an average surface roughness of at least 0.86, wherein the average surface roughness is an average of SF1 of respective toner particles, where SF1 is defined as follows:SF1=Le/Ipwherein Le and Lp represent the length of the minimum envelope line and the peripheral length of each toner particle, respectively.
    Type: Grant
    Filed: January 29, 1997
    Date of Patent: June 15, 1999
    Assignee: Ricoh Company, Ltd.
    Inventors: Mituo Aoki, Masanori Suzuki, Akihiro Kotsugai
  • Patent number: 5429901
    Abstract: A toner for use in electrostatic development is composed of toner particles, each toner particle being composed of a core particle containing a thermoplastic resin and a coloring agent; a releasing agent in the form of particles, which substantially cover the entire surface of the core particle; and a chargeable resin which covers at least part of the releasing agent.
    Type: Grant
    Filed: October 18, 1993
    Date of Patent: July 4, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Kenkichi Muto, Yohichiro Watanabe, Akihiro Kotsugai
  • Patent number: 5418103
    Abstract: A toner prepared by allowing finely-divided particles of a vinyl resin having an alkali-reactive group to react with a fluorine-containing quaternary ammonium salt to obtain surface-modified finely-divided particles; mixing the surface-modified finely-divided particles and core particles composed of a resin and a coloring agent; and filming the above core particles with the finely-divided particles of the surface-modified vinyl resin with application of mechanical energy thereto.
    Type: Grant
    Filed: September 18, 1992
    Date of Patent: May 23, 1995
    Assignee: Ricoh Company, Ltd.
    Inventors: Kenkichi Muto, Hiroyuki Fushimi, Akihiro Kotsugai, Yoichiro Watanabe, Ian Harpur