Patents by Inventor Keiko Shiraishi

Keiko Shiraishi 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: 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
  • Patent number: 6566026
    Abstract: A toner including mother toner particles including at least two resins A and B and a wax each of which is incompatible with the others; and an external additive including at least one of a particulate inorganic material and a particulate resin, wherein the resins and wax form a sea-island structure in which the resin B is present like islands in a sea of the resin A and the wax is substantially included in the resin B while dispersed therein, and wherein the resin A does not include a component insoluble in tetrahydrofuran and has a weight average molecular weight of from 10,000 to 90,000.
    Type: Grant
    Filed: June 26, 2001
    Date of Patent: May 20, 2003
    Assignee: Ricoh Company,. Ltd.
    Inventors: Yohichiroh Watanabe, Masanori Suzuki, Masahide Yamashita, Keiko Shiraishi, Kazuhito Watanabe, Kohki Katoh, Toyoshi Sawada, Takuya Saito
  • Publication number: 20030077534
    Abstract: A charge control agent containing a barium salt of a sulfoisophthalic acid compound and optionally a metal salt of a salicylic acid compound. A toner for developing an electrostatic latent image comprising such a charge control agent, a binder resin and a colorant.
    Type: Application
    Filed: June 7, 2002
    Publication date: April 24, 2003
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Toyoshi Sawada, Takuya Saito, Tatsuhiko Osaki, Satoshi Aratani, Hiroki Ogiso
  • Publication number: 20030039909
    Abstract: A toner, a developing method and apparatus is provided to satisfy both the low temperature fixation property and the hot offset property and that has a wide range of fixing temperature. The toner for an image formation comprises at least metal materials in a binding resin, wherein the toner is measured by a stand-alone type flow tester, and has a softening temperature of 65˜77.5° C., a flow beginning temperature of 100˜120° C., a melt temperature by a ½ method is 145˜195° C., and an average length of a short axis of a primary particle of the metal materials is 0.01-0.4 &mgr;m.
    Type: Application
    Filed: March 22, 2002
    Publication date: February 27, 2003
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Keiko Shiraishi, Takuya Saito
  • Publication number: 20030036010
    Abstract: A toner for developing a latent electrostatic image to a toner image, including a binder resin, and a magnetic material which is blackened by coating the surface of a magnetic powder with a coloring agent, the magnetic material being in an amount of 10 wt. % to 40 wt. % of the entire weight of the toner, a method of forming an image, using a two-component developer containing the toner, an image formation apparatus using the two-component developer, and a toner container containing therein the toner, and an image formation apparatus equipped with the toner container are proposed.
    Type: Application
    Filed: April 5, 2001
    Publication date: February 20, 2003
    Inventors: Masanori Suzuki, Yohichiroh Watanabe, Masahide Yamashita, Kazuhito Watanabe, Keiko Shiraishi, Kohki Katoh
  • 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
  • Publication number: 20020037467
    Abstract: A toner including mother toner particles including at least two resins A and B and a wax each of which is incompatible with the others; and an external additive including at least one of a particulate inorganic material and a particulate resin, wherein the resins and wax form a sea-island structure in which the resin B is present like islands in a sea of the resin A and the wax is substantially included in the resin B while dispersed therein, and wherein the resin A does not include a component insoluble in tetrahydrofuran and has a weight average molecular weight of from 10,000 to 90,000.
    Type: Application
    Filed: June 26, 2001
    Publication date: March 28, 2002
    Inventors: Yohichiroh Watanabe, Masanori Suzuki, Masahide Yamashita, Keiko Shiraishi, Kazuhito Watanabe, Kohki Katoh, Toyoshi Sawada, Takuya Saito
  • Patent number: 6363229
    Abstract: A method for fixing full-color toner images on an image receiving member so that the fixed toner images selectively exhibit different glossinesses includes the step of bringing the transferred toner images into contact with a heater, with linear speeds being selectively switched in such a manner that the fixed toner images exhibit a mean surface roughness in a range of 9.5 to 16 &mgr;m at a linear speed (A), and the fixed toner images exhibit a mean surface roughness of less than 8 &mgr;m at a linear speed (B), wherein the linear speed (A) is in a range of 100 to 300 mm/sec, the linear speed (B) is lower than the linear speed (A) by 25 mm/sec or more, and the image fixing temperatures are equal at the linear speeds (A) and (B). A method for fixing full-color toner images with high glossiness on an image receiving member includes the step of bringing the transferred toner images into contact with a belt so that the fixed toner images exhibit a mean surface roughness of less than 8 &mgr;m.
    Type: Grant
    Filed: November 16, 2000
    Date of Patent: March 26, 2002
    Assignee: Ricoh Company, Ltd.
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Kazuhito Watanabe, Masahide Yamashita, Kohki Katoh, Masami Tomita, Yasuo Asahina, Yasuaki Iwamoto
  • Patent number: 6269210
    Abstract: An optical fiber ribbon includes a plurality of optical fibers arranged in a row and an outer coating formed around the optical fibers. Each of the optical fibers has a core, a cladding, and a non-strippable thin coating made of synthetic resin with a Young's modulus of 50 kg/mm2 to 250 kg/mm2 at room temperature and coated around the cladding. The concentricity of the core to the diameter of the non-strippable thin coating is 1 &mgr;m or less.
    Type: Grant
    Filed: April 29, 1999
    Date of Patent: July 31, 2001
    Assignees: Showa Electric Wire & Cable Co., Ltd., Nippon Telegraph and Telephone Corp.
    Inventors: Kenji Yagi, Tomotaka Murase, Keiko Shiraishi, Ken-ichi Muta, Yuichi Morishita, Takashi Yoshida, Masaru Kobayashi, Koichi Arishima, Shin Sumida
  • Patent number: 6180298
    Abstract: A multi-color toner set includes a plurality of color toners with different colors, each color toner including toner particles, each toner particle including a binder resin, a pigment and a releasing agent, at least part of the releasing agent being present in the form of domains in the binder resin, with a difference between a maximum content and a minimum content of the releasing agent in the form of domains in the binder resin in each of the color toners being in a range of 20% or less. Multi-color images can be formed, using this multi-color toner set.
    Type: Grant
    Filed: April 16, 1999
    Date of Patent: January 30, 2001
    Assignee: Ricoh Company, Ltd.
    Inventors: Noboru Kuroda, Kohsuke Suzuki, Yohichiroh Watanabe, Keiko Shiraishi
  • Patent number: 6103441
    Abstract: A color toner for electrophotography is made of matrix toner particles, each matrix toner particle containing a binder resin, a coloring agent, and a charge control agent, and an externally added additive which includes (a) hydrophobically treated silica particles having a primary particle size of 0.01 to 0.03 .mu.m, (b) hydrophobically treated titanium oxide particles having a primary particle size of 0.01 to 0.03 .mu.m and a specific surface area of 60 to 140 m.sup.2 /g, and (c) hydrophobically treated silica particles having a specific surface area of 20 to 50 m.sup.2 /g and a bulk density of 100 to 250 g/l.
    Type: Grant
    Filed: November 12, 1999
    Date of Patent: August 15, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Masami Tomita, Hiroyuki Fushimi, Yohichiroh Watanabe, Keiko Shiraishi
  • Patent number: 6074795
    Abstract: A toner for developing electrostatic latent images which includes at least a binder resin, a colorant and a releasing agent, wherein the releasing agent includes a particulate material capable of absorbing the releasing agent. The particulate material preferably has an absorption rate not less than about 10% by weight in a combination with the releasing agent.
    Type: Grant
    Filed: July 1, 1999
    Date of Patent: June 13, 2000
    Assignee: Ricoh Company, Ltd.
    Inventors: Yohichiroh Watanabe, Keiko Shiraishi, Noboru Kuroda, Kohsuke Suzuki
  • Patent number: 5576393
    Abstract: Polymer particles which are substantially spherical and have protrusions on the surface thereof, with such a particle size distribution that the volume mean diameter dv thereof is 1.ltoreq.dv.ltoreq.15 (.mu.m), and the ratio of the volume mean diameter dv to the number mean diameter dn thereof, that is, dv/dn, is 1.ltoreq.dv/dn.ltoreq.1.2, are prepared, and used as a component for a toner for use in electrophotography.
    Type: Grant
    Filed: May 26, 1995
    Date of Patent: November 19, 1996
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Yamashita, Hiromitsu Kawase, Keiko Shiraishi
  • Patent number: 5541031
    Abstract: Polymer particles which are substantially spherical and have protrusions on the surface thereof, with such a particle size distribution that the volume mean diameter dv thereof is 1.ltoreq.dv.ltoreq.15 (.mu.m), and the ratio of the volume mean diameter dv to the number mean diameter dn thereof, that is, dv/dn, is 1.ltoreq.dv/dn.ltoreq.1.2, are prepared, and used as a component for a toner for use in electrophotography.
    Type: Grant
    Filed: May 24, 1995
    Date of Patent: July 30, 1996
    Assignee: Ricoh Company, Ltd.
    Inventors: Hiroshi Yamashita, Hiromitsu Kawase, Keiko Shiraishi