Patents by Inventor Yohichiroh Watanabe

Yohichiroh Watanabe 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: 6977129
    Abstract: A charge control agent containing a calcium salt of a sulfoisophthalic acid compound. A toner for developing an electrostatic latent image including the above charge control agent, a binder resin and a colorant.
    Type: Grant
    Filed: December 9, 2002
    Date of Patent: December 20, 2005
    Assignees: Ricoh Company, Ltd., Takemoto Yushi Kabushiki Kaisha
    Inventors: Takuya Saito, Masanori Suzuki, Yohichiroh Watanabe, Keiko Shiraishi, Toyoshi Sawada, Tatsuhiko Osaki, Satoshi Aratani, Hiroki Ogiso
  • Publication number: 20050277046
    Abstract: A color toner including toner particles including a colorant, a binder resin, and a wax; and an external additive including at least one of an inorganic particulate material and a particulate resin, wherein the binder resin includes a polyester resin (A) having a crystallinity and a formula (—O—CO—CR1?CR2—CO—O—(CH2)n—)m, wherein R1 and R2 independently represents a hydrocarbon, and n and m are repeating numbers; a resin (B); and a resin (C), wherein the resins (B) and (C) and the wax have an island-sea structure such that the resin (C) is present like islands in a sea of the resin (B) and the wax is substantially included in the resin (C). A toner container, an image forming method, an image forming apparatus and a process cartridge including the color toner are also provided.
    Type: Application
    Filed: August 4, 2005
    Publication date: December 15, 2005
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Keiko Shiraishi, Takuya Saito, Masashi Nagayama
  • Publication number: 20050238982
    Abstract: An image-forming color toner contains at least a colorant, a resin (A), a modified resin (B) and a wax (a) as a mold releasing agent, the image-forming color toner having a phase separated structure comprising the modified resin (B) as a domain in the resin (A) as a continuous phase, and wax (a) being effectively contained the modified resin (B). The modified resin (B) has a wax part containing a wax component (b), and a modified part formed of a vinyl monomer unit and an average ester group concentration of 8% by weight to 30% by weight.
    Type: Application
    Filed: June 28, 2005
    Publication date: October 27, 2005
    Inventors: Masanori Suzuki, Yohichiroh Watanabe, Keiko Shiraishi, Toyoshi Sawada, Takuya Saito, Masashi Nagayama
  • 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: 20050196691
    Abstract: A method of preparing a toner in an aqueous medium, including: preparing a dispersion or an emulsion of a toner composition comprising a resin including a carboxyl group and a colorant; and mixing an aromatic compound having a carboxyl group with the dispersion or emulsion, such that the carboxyl group on a surface of the toner is connected with the carboxyl group of the aromatic compound by hydrogen bonding.
    Type: Application
    Filed: January 6, 2005
    Publication date: September 8, 2005
    Inventors: Shinji Ohtani, Hiroshi Yamashita, Yohichiroh Watanabe, Tsunemi Sugiyama, Takuya Saito
  • Patent number: 6939653
    Abstract: An image-forming color toner contains at least a colorant, a resin (A), a modified resin (B) and a wax (a) as a mold releasing agent, the image-forming color toner having a phase separated structure comprising the modified resin (B) as a domain in the resin (A) as a continuous phase, and wax (a) being effectively contained the modified resin (B). The modified resin (B) has a wax part containing a wax component (b), and a modified part formed of a vinyl monomer unit and an average ester group concentration of 8% by weight to 30% by weight.
    Type: Grant
    Filed: December 27, 2002
    Date of Patent: September 6, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Masanori Suzuki, Yohichiroh Watanabe, Keiko Shiraishi, Toyoshi Sawada, Takuya Saito, Masashi Nagayama
  • Publication number: 20050079433
    Abstract: An image forming method including forming an electrostatic latent image on an image bearing member; developing the electrostatic latent image with a developer including a toner to prepare a toner image on the image bearing member; transferring the toner image onto a receiving material; and cleaning the surface of the image bearing member with a cleaning blade; wherein a surface of the image bearing member has a friction coefficient of from 0.10 to 0.40, and wherein the toner has an average circularity of from 0.97 to 1.00 and includes toner particles and a particulate material having an average particle diameter of from 0.03 to 1 ?m, wherein the particulate material is externally added to the toner particles by a wet method.
    Type: Application
    Filed: October 5, 2004
    Publication date: April 14, 2005
    Inventors: Yohichiroh Watanabe, Hiroshi Yamashita, Tsunemi Sugiyama, Shinji Ohtani, Takuya Saito, Hidetoshi Kami
  • Patent number: 6858365
    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 ?m.
    Type: Grant
    Filed: March 22, 2002
    Date of Patent: February 22, 2005
    Assignee: Ricoh Company, Ltd.
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Keiko Shiraishi, Takuya Saito
  • Publication number: 20050003288
    Abstract: A method for preparing a toner including toner particles, including granulating a toner constituent mixture to prepare toner constituent particles having a polar group with a first polarity on a surface thereof; and mixing a surfactant having a second polarity different from the first polarity and a particulate material with the toner constituent particles to prepare the toner particles. A toner prepared by the method mentioned above. An image forming method including developing a latent image with the toner; transferring the toner image on a receiving material optionally via an intermediate transfer medium, and fixing the toner image on the receiving material. A process cartridge including a developer container containing a developer including the toner mentioned above, and at least one of an image bearing member; a charger; a developing device; and a cleaner.
    Type: Application
    Filed: June 28, 2004
    Publication date: January 6, 2005
    Inventors: Tsunemi Sugiyama, Hiroshi Yamashita, Yohichiroh Watanabe, Shinji Ohtani, Takuya Saito
  • Publication number: 20040259013
    Abstract: A method for preparing a functional particulate organic material, including providing a suspension of a particulate organic material having an acid group on a surface thereof; reacting a metal cation with tri- or more-valence with the acid group; and reacting at least one of an organic acid and an organic acid salt with the metal cation. A toner prepared by the method mentioned above. An image forming method including developing a latent image with the toner; transferring the toner image on a receiving material optionally via an intermediate transfer medium, and fixing the toner image on the receiving material. A process cartridge including a developer container containing a developer including the toner mentioned above, and at least one of an image bearing member; a charger; a developing device; and a cleaner.
    Type: Application
    Filed: June 21, 2004
    Publication date: December 23, 2004
    Inventors: Shinji Ohtani, Hiroshi Yamashita, Yohichiroh Watanabe, Tsunemi Sugiyama, Takuya Saito
  • Patent number: 6830859
    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: Grant
    Filed: June 7, 2002
    Date of Patent: December 14, 2004
    Assignees: Ricoh Company, Ltd., Takemoto Yushi Kabushiki Kaisha
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Toyoshi Sawada, Takuya Saito, Tatsuhiko Osaki, Satoshi Aratani, Hiroki Ogiso
  • Patent number: 6821698
    Abstract: A toner for developing electrostatic latent images, including a colorant, a releasing agent and a binder resin, wherein the binder resin comprises a first, crystalline polyester resin, and a second, amorphous polyester resin having a softening point higher than that of the first polyester resin and being incompatible with the first polyester resin.
    Type: Grant
    Filed: September 23, 2002
    Date of Patent: November 23, 2004
    Assignee: Ricoh Company, LTD
    Inventors: Toyoshi Sawada, Masanori Suzuki, Yohichiroh Watanabe, Keiko Shiraishi, Takuya Saito
  • Publication number: 20040185365
    Abstract: The present invention relates to a toner useful, for example, for visualizing an electrostatic latent image formed on an image bearing member by a method such as electrophotography and electrostatic recording methods. In addition, the present invention also relates, without limitation, to a developer including a toner, a developing method using a toner and a method of preparing the toner.
    Type: Application
    Filed: March 18, 2004
    Publication date: September 23, 2004
    Inventors: Takuya Saito, Hiroshi Yamashita, Yohichiroh Watanabe, Tsunemi Sugiyama
  • Publication number: 20040137344
    Abstract: The method of manufacturing toner for electrophotography includes the steps of dissolving or dispersing a toner composition containing a resin and a coloring agent into polymerizable monomers to provide a solution or a dispersed system, emulsifying the solution or the dispersed system with a first surface active agent in an aqueous medium to provide an emulsion, and polymerizing the polymerizable monomers in the emulsion to obtain toner. A second surface active agent having polarity opposite to polarity of the first surface active agent is added after the emulsifying step.
    Type: Application
    Filed: July 22, 2003
    Publication date: July 15, 2004
    Inventors: Hiroshi Yamashita, Takuya Saito, Tsunemi Sugiyama, Yohichiroh Watanabe
  • Publication number: 20040131961
    Abstract: A toner composition including toner particles including a binder resin including a modified polyester resin, and a second resin having a weight average molecular weight of from 2,000 to 10,000; a colorant; a release agent; and a particulate material which is present at least a surface portion of the toner particles while embedded into the surface portion, wherein the binder resin has a glass transition temperature not lower than 35° C. and lower than 55° C., and wherein the particulate material has an average particle diameter of from 0.002 to 0.2 times that of the toner particles. A developer including the toner composition and a carrier having a layer thereon which includes at least an acrylic resin and a silicone resin, and a method for fixing an image of the toner composition are also provided.
    Type: Application
    Filed: September 26, 2003
    Publication date: July 8, 2004
    Applicant: RICOH COMPANY LIMITED
    Inventors: Yohichiroh Watanabe, Masanori Suzuki, Tsunemi Sugiyama, Hiroshi Yamashita, Takuya Saito, Naohiro Watanabe, Masami Tomita, Shigeru Emoto, Shinichiro Yagi, Hiroshi Yamada, Toshiki Nanya, Tadao Takigawa
  • 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: 20040115551
    Abstract: An improved toner comprises a binder resin comprising a urea-modified polyester resin; a colorant master batch comprising a colorant; a resin; and a pigment dispersant. The toner is prepared by a method comprising dissolving or dispersing toner compositions including a modified polyester resin capable of forming the urea-modified polyester resin and the colorant master batch in an organic solvent to provide a liquid; dispersing the liquid in an aqueous medium including resin fine particles while reacting the modified polyester resin with at least one of a crosslinker and an elongation agent to provide particles; and washing the particles after removing the organic solvent therefrom.
    Type: Application
    Filed: October 1, 2003
    Publication date: June 17, 2004
    Applicant: RICOH COMPANY, LTD.
    Inventors: Tsunemi Sugiyama, Hiroshi Yamashita, Yohichiroh Watanabe, Takuya Saito, Takeshi Takada, Masanori Suzuki
  • Patent number: 6740461
    Abstract: A carrier is composed of carrier particles, each carrier particle having a core particle containing at least a magnetic material and a surface coating layer provided on the core particle containing at least a resin, the surface coating layer being constituted of a plurality of regions, the regions being separately formed and joined together to form a complex configuration, and having different phase lags when the surface coating layer is subjected to scanning by phase imaging measurement using a scanning probe microscope in a tapping mode, wherein a region having a phase lag over the average phase lag obtained from Eavg=&Sgr;(E(i)·S(i))/&Sgr;S(i) has an area SO, and SO and &Sgr;S(i) are in a relationship of 10%≦SO/&Sgr;S(i)×100≦90% when each region comprises a component A(i) having an area S(i) and a phase lag E(i), in which i represents the number of regions with different phase lags. A two-component developer employs the above-mentioned carrier.
    Type: Grant
    Filed: December 20, 2002
    Date of Patent: May 25, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamashita, Masanori Suzuki, Yohichiroh Watanabe, Kazuhito Watanabe, Keiko Shiraishi, Kohki Katoh
  • Patent number: 6716561
    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: Grant
    Filed: November 27, 2001
    Date of Patent: April 6, 2004
    Assignee: Ricoh Company, Ltd.
    Inventors: Keiko Shiraishi, Masanori Suzuki, Yohichiroh Watanabe, Masahide Yamashita, Akihiro Kotsugai, Toyoshi Sawada, Kohki Katoh
  • Publication number: 20030219670
    Abstract: A color toner including toner particles including a colorant, a binder resin, and a wax; and an external additive including at least one of an inorganic particulate material and a particulate resin, wherein the binder resin includes a polyester resin (A) having a crystallinity and a formula (—O—CO—CR1═CR2—CO—O—(CH2)n—)m, wherein R1 and R2 independently represents a hydrocarbon, and n and m are repeating numbers; a resin (B); and a resin (C), wherein the resins (B) and (C) and the wax have an island-sea structure such that the resin (C) is present like islands in a sea of the resin (B) and the wax is substantially included in the resin (C). A toner container, an image forming method, an image forming apparatus and a process cartridge including the color toner are also provided.
    Type: Application
    Filed: May 23, 2003
    Publication date: November 27, 2003
    Inventors: Toyoshi Sawada, Masanori Suzuki, Kohki Katoh, Yohichiroh Watanabe, Keiko Shiraishi, Takuya Saito, Masashi Nagayama