Patents by Inventor Yasuaki Iwamoto

Yasuaki Iwamoto 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: 20050208408
    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: Application
    Filed: March 16, 2005
    Publication date: September 22, 2005
    Inventors: Osamu Uchinokura, Masami Tomita, Hisashi Nakajima, Shinya Nakayama, Koichi Sakata, Akihiro Kotsugai, Tomoyuki Ichikawa, Yasuo Asahina, Hideki Sugiura, Yasuaki Iwamoto, Satoshi Mochizuki
  • Patent number: 6946229
    Abstract: A color toner which gives a suitable image gloss and has an excellent color reproducibility, which has sufficient anti-offset properties even when a release oil is not coated on a fixing roller or is coated in only a small amount, and which has excellent transfer properties, durability, and charge stability relative to humidity is disclosed. Also, an image-forming apparatus using the color toner and a toner container filled with the color toner are disclosed. The color toner comprises a continuous phase of a resin containing a urea-modified polyester resin; and a modified resin dispersed in the continuous phase, wherein the modified resin contains a release polymer portion containing a release polymer; and a modified portion containing a plurality of vinyl monomer units, the modified portion having an average ester group concentration of 8% by weight to 30% by weight.
    Type: Grant
    Filed: August 26, 2003
    Date of Patent: September 20, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Masanori Suzuki, Takuya Saito, Hiroshi Yamashita, Yohichiroh Watanabe, Takeshi Takada, Tsunemi Sugiyama, Satoshi Mochizuki, Yasuaki Iwamoto, Takayuki Koike
  • Publication number: 20050191575
    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: Application
    Filed: January 20, 2004
    Publication date: September 1, 2005
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Kazuhiko Umemura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Patent number: 6911289
    Abstract: A toner including toner particles including a binder resin and a release agent, wherein when the toner is molded into a plate upon application of a pressure of 478 kg/cm2, the toner plate has a surface having a coefficient of static friction of from 0.20 to 0.40. An image forming apparatus including an image bearing member, an image developer to form a toner image on the image bearing member, an image transferer configured to transfer the toner image on a receiving material and a fixer configured to fix the toner image thereon, wherein the apparatus has a waiting time not longer than 15 seconds, and a maximum power consumption not greater than 1.5 KW and 30 W in an image forming state and in a standby state, respectively, wherein the toner is the toner mentioned above.
    Type: Grant
    Filed: October 1, 2001
    Date of Patent: June 28, 2005
    Assignee: Ricoh Company Limited
    Inventors: Hiroto Higuchi, Fumihiro Sasaki, Yasuaki Iwamoto, Hiroshi Nakai, Bing Shu, Hiroaki Matsuda, Maiko Kondo
  • Publication number: 20050089787
    Abstract: An image forming method including: forming a toner image on a support using a toner including toner particles; and feeding the support bearing the toner image thereon through a nip between an endless toner heating member and a pressure roller to fix the toner image on the support, wherein the endless toner heating member is rotated while stretched by a fixing roller and a heat roller which includes a magnetic metal and which is heated by electromagnetic induction, and wherein the pressure roller presses the support to the endless toner heating member and the fixing roller at the nip, wherein the toner particles are prepared by a polymerizing method using a binder resin containing at least a modified polyester resin.
    Type: Application
    Filed: October 21, 2004
    Publication date: April 28, 2005
    Inventors: Osamu Uchinokura, Akihiro Kotsugai, Yasuo Asahina, Tomoyuki Ichikawa, Shinya Nakayama, Kohichi Sakata, Tomoko Utsumi, Hisashi Nakajima, Yasuaki Iwamoto, Hideki Sugiura, Satoshi Mochizuki
  • Publication number: 20050089786
    Abstract: A toner including a binder resin; and a colorant, wherein a hexafluoroisopropanol (HFIP)-soluble component satisfies the following relationship: 2,000?Mn?7,000 and 1.5?Mn/Mw?10 wherein Mn represents a number-average molecular weight and Mw represents a weight-average molecular weight.
    Type: Application
    Filed: October 7, 2004
    Publication date: April 28, 2005
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Akihiro Kotsugai, Yasuo Asahina, Osamu Uchinokura, Hisashi Nakajima, Tomoyuki Ichikawa, Shinya Nakayama, Kohichi Sakata, Tomoko Utsumi, Hitoshi Iwatsuki, Yasuaki Iwamoto
  • Patent number: 6856781
    Abstract: An image forming apparatus including a photoconductor, and a developing unit having a developing sleeve for carrying a developer and a developer regulating plate for regulating the amount of the developer carried on the sleeve, wherein the developer is composed of a carrier and a toner, wherein that portion of the toner which has a particle diameter of 2.0-4.0 ?m accounts for 30-70% of a total number thereof, and wherein the developer regulating plate is grounded so that when the developing sleeve is applied with a bias voltage, an electric field is formed between the developer regulating plate and the developing sleeve, whereby toner deposits on the developing sleeve are transferred to the developer regulating plate.
    Type: Grant
    Filed: February 20, 2002
    Date of Patent: February 15, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroaki Matsuda, Yasuaki Iwamoto, Hiroshi Nakai, Hiroto Higuchi, Bing Shu, Maiko Kondo, Fumihiro Sasaki
  • Publication number: 20050026064
    Abstract: A toner for developing an electrostatic image, includes: a colorant; and a binder resin. The toner has a particle including at least one pore having a diameter of 10 nm or over, and a porosity thereof is in a range from 0.01 to 0.60.
    Type: Application
    Filed: June 25, 2004
    Publication date: February 3, 2005
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Akihiro Kotsugai, Shinya Nakayama, Tomoyuki Ichikawa, Koichi Sakata, Tomoko Utsumi, Hisashi Nakajima
  • Patent number: 6835517
    Abstract: A toner including at least a binder resin; a colorant; a charge controlling agent; and a wax (B), in which the charge controlling agent comprises a compound selected from the group consisting of: an aromatic oxycarboxylic acids, derivatives of aromatic oxycarboxylic acid, salts of aromatic oxycarboxylic acids and salts of derivatives of aromatic oxycarboxylic acids; and a zirconium compound (A), and in which the zirconium compound (A) and the wax (B) have a weight ratio (A/B) satisfying the following relationship: 3.0≦(A/B)×100≦60.
    Type: Grant
    Filed: May 21, 2002
    Date of Patent: December 28, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Maiko Kondo, Yasuaki Iwamoto, Fumihiro Sasaki, Hiroto Higuchi, Bing Shu, Yasushi Koichi
  • Publication number: 20040229143
    Abstract: A toner for electrophotography contains a binder resin, a colorant and a releasing agent and has a viscosity, a storage modulus (G′) and a loss modulus (G″), in which the viscosity is 1×103 Pa.s or more and a loss tangent (tan &dgr;) as the ratio of G′ to G″ is 0.4 or more at temperatures from 140° C. to 170° C.
    Type: Application
    Filed: February 24, 2004
    Publication date: November 18, 2004
    Inventors: Kazuhiko Umemura, Satoshi Mochizuki, Yasuaki Iwamoto, Yasuo Asahina, Hideki Sugiura, Tomoyuki Ichikawa, Shinya Nakayama, Koichi Sakata, Tomoko Utsumi
  • Publication number: 20040224247
    Abstract: An image formation method includes the steps of charging the surface of an electrophotographic photoconductor, exposing the charged photoconductor to a light image to form a latent electrostatic image on the photoconductor, developing the latent electrostatic image using a two-component developer containing a toner and a carrier to obtain a toner image, and transferring the toner image to an image receiving material directly or via an intermediate transfer member, with the photoconductor showing a surface friction coefficient of 0.40 or less, and the toner having toner particles with an average circularity of 0.930 or more.
    Type: Application
    Filed: June 21, 2004
    Publication date: November 11, 2004
    Inventors: Fumihiro Sasaki, Mitsuo Aoki, Yasuaki Iwamoto, Naohito Shimota, Kazuyuki Yazaki, Hiroaki Matsuda, Hiroshi Nakai, Kumi Hasegawa, Shinichiro Yagi, Hiroto Higuchi, Akemi Sugiyama
  • Patent number: 6813461
    Abstract: A toner including toner particles including a binder resin and a release agent, wherein when the toner is molded into a plate upon application of a pressure of 478 kg/cm2, the toner plate has a surface having a coefficient of static friction of from 0.20 to 0.40. An image forming apparatus including an image bearing member, an image developer to form a toner image on the image bearing member, an image transferer configured to transfer the toner image on a receiving material and a fixer configured to fix the toner image thereon, wherein the apparatus has a waiting time not longer than 15 seconds, and a maximum power consumption not greater than 1.5 KW and 30 W in an image forming state and in a standby state, respectively, wherein the toner is the toner mentioned above.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: November 2, 2004
    Assignee: Ricoh Company Limited
    Inventors: Hiroto Higuchi, Fumihiro Sasaki, Yasuaki Iwamoto, Hiroshi Nakai, Bing Shu, Hiroaki Matsuda, Maiko Kondo
  • Patent number: 6811944
    Abstract: A toner including toner particles including a binder resin and a release agent, wherein when the toner is molded into a plate upon application of a pressure of 478 kg/cm2, the toner plate has a surface having a coefficient of static friction of from 0.20 to 0.40. An image forming apparatus including an image bearing member, an image developer to form a toner image on the image bearing member, an image transferer configured to transfer the toner image on a receiving material and a fixer configured to fix the toner image thereon, wherein the apparatus has a waiting time not longer than 15 seconds, and a maximum power consumption not greater than 1.5 KW and 30 W in an image forming state and in a standby state, respectively, wherein the toner is the toner mentioned above.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: November 2, 2004
    Assignee: Ricoh Company Limited
    Inventors: Hiroto Higuchi, Fumihiro Sasaki, Yasuaki Iwamoto, Hiroshi Nakai, Bing Shu, Hiroaki Matsuda, Maiko Kondo
  • Patent number: 6790575
    Abstract: A two component developer comprising a magnetic toner containing a binder resin and a magnetic particle, and a magnetic carrier containing a magnetic particle, wherein the magnetic toner has an average particle diameter of 4.0 to 10.0 &mgr;m, and contains 5 to 80 No. % of toner particles having particle diameter of 5 &mgr;m or less, and exhibits magnetization of 10 to 25 emu/g under magnetic field of 5 kiloersteds.
    Type: Grant
    Filed: March 21, 2002
    Date of Patent: September 14, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Fumihiro Sasaki, Hiroaki Matsuda, Bing Shu, Maiko Kondo, Hiroshi Nakai, Hiroto Higuchi, Yasuaki Iwamoto, Yoshihiro Suguro, Hiroyuki Yoshikawa, Masahide Yamashita, Kazuyuki Yazaki
  • Publication number: 20040166428
    Abstract: A toner including toner particles including a binder resin and a release agent, wherein when the toner is molded into a plate upon application of a pressure of 478 kg/cm2, the toner plate has a surface having a coefficient of static friction of from 0.20 to 0.40. An image forming apparatus including an image bearing member, an image developer to form a toner image on the image bearing member, an image transferer configured to transfer the toner image on a receiving material and a fixer configured to fix the toner image thereon, wherein the apparatus has a waiting time not longer than 15 seconds, and a maximum power consumption not greater than 1.5 KW and 30 W in an image forming state and in a standby state, respectively, wherein the toner is the toner mentioned above.
    Type: Application
    Filed: February 26, 2004
    Publication date: August 26, 2004
    Inventors: Hiroto Higuchi, Fumihiro Sasaki, Yasuaki Iwamoto, Hiroshi Nakai, Bing Shu, Hiroaki Matsuda, Maiko Kondo
  • Publication number: 20040166429
    Abstract: A toner including toner particles including a binder resin and a release agent, wherein when the toner is molded into a plate upon application of a pressure of 478 kg/cm2, the toner plate has a surface having a coefficient of static friction of from 0.20 to 0.40. An image forming apparatus including an image bearing member, an image developer to form a toner image on the image bearing member, an image transferer configured to transfer the toner image on a receiving material and a fixer configured to fix the toner image thereon, wherein the apparatus has a waiting time not longer than 15 seconds, and a maximum power consumption not greater than 1.5 KW and 30 W in an image forming state and in a standby state, respectively, wherein the toner is the toner mentioned above.
    Type: Application
    Filed: February 26, 2004
    Publication date: August 26, 2004
    Inventors: Hiroto Higuchi, Fumihiro Sasaki, Yasuaki Iwamoto, Hiroshi Nakai, Bing Shu, Hiroaki Matsuda, Maiko Kondo
  • Publication number: 20040121256
    Abstract: A color toner which gives a suitable image gloss and has an excellent color reproducibility, which has sufficient anti-offset properties even when a release oil is not coated on a fixing roller or is coated in only a small amount, and which has excellent transfer properties, durability, and charge stability relative to humidity is disclosed. Also, an image-forming apparatus using the color toner and a toner container filled with the color toner are disclosed. The color toner comprises a continuous phase of a resin containing a urea-modified polyester resin; and a modified resin dispersed in the continuous phase, wherein the modified resin contains a release polymer portion containing a release polymer; and a modified portion containing a plurality of vinyl monomer units, the modified portion having an average ester group concentration of 8% by weight to 30% by weight.
    Type: Application
    Filed: August 26, 2003
    Publication date: June 24, 2004
    Inventors: Masanori Suzuki, Takuya Saito, Hiroshi Yamashita, Yohichiroh Watanabe, Takeshi Takada, Tsunemi Sugiyama, Satoshi Mochizuki, Yasuaki Iwamoto, Takayuki Koike
  • Publication number: 20040115550
    Abstract: Spherical toners having excellent fusibility are disclosed. The toners are fusible at low temperatures and are excellent in preservability and therefore charge properties, flowability, and transferability do not deteriorate. The toners contain a colorant and a nitrogen-containing polyester resin, in which the concentration of nitrogen at the surface of toner particles is higher than the concentration of nitrogen of the entire particles. The ratio of the surface concentration to the overall concentration is from 1.2 to 10. Additionally, the nitrogen-containing resin is preferably a polyester resin modified by urea bonds. Also, it is preferred that the toner particles are substantially spherical having an average spherity E of from 0.90 to 0.99.
    Type: Application
    Filed: August 21, 2003
    Publication date: June 17, 2004
    Inventors: Hideki Sugiura, Satoshi Mochizuki, Yasuaki Iwamoto, Kazuhiko Umemura, Yasuo Asahina, Shinya Nakayama
  • Patent number: 6699632
    Abstract: An image forming toner is provided, including at least: a binder resin; a colorant; and a release agent, wherein a volume-average particle diameter of the toner measured by a Coulter counter is from 5 to 8 &mgr;m; the content of the toner having a volume-average particle diameter of not greater than 5 &mgr;m is 60 to 75% by number; and the content of the toner having a number-basis circle-equivalent particle diameter of from 0.6 to 3 &mgr;m measured by a flow-type particle image analyzer is not greater than 25%.
    Type: Grant
    Filed: November 30, 2001
    Date of Patent: March 2, 2004
    Assignee: Ricoh Company Limited
    Inventors: Hiroto Higuchi, Fumihiro Sasaki, Yasuaki Iwamoto, Hiroaki Matsuda, Hiroshi Nakai, Bing Shu, Maiko Kondo
  • Patent number: 6667141
    Abstract: An image forming method and apparatus, wherein a surface of a photoconductor is charged with a contact-type charging roller having a surface roughness of 2-40 &mgr;m, and exposed imagewise to form an electrostatic latent image thereon, the latent image being developed with a toner, transferred to a transfer member and fixed, and wherein the toner comprises a colorant, and a binder resin containing a tetrahydrofuran-soluble component having such a molecular weight distribution that at least one peak having a half width not greater than 15,000 is present between 1,000 and 10,000 when measured by gel permeation chromatography.
    Type: Grant
    Filed: February 20, 2002
    Date of Patent: December 23, 2003
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasuaki Iwamoto, Fumihiro Sasaki, Hiroaki Matsuda, Hiroshi Nakai, Hiroto Higuchi, Bing Shu, Maiko Kondo