Patents by Inventor Toyoshi Sawada

Toyoshi Sawada 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: 8263302
    Abstract: A carrier for electrophotographic developer, including a core material; and a layer comprising a binder resin, located overlying the core material, wherein the binder resin includes a segment including one or more polymerizable vinyl monomers as a structural unit; and another segment including a partial cleavage structure of polyhedral oligomeric silsesquioxane and/or another partial cleavage structure of polyhedral oligomeric silsesquioxane as a structural unit.
    Type: Grant
    Filed: September 8, 2009
    Date of Patent: September 11, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoshihiro Moriya, Akihiro Kotsugai, Toyoshi Sawada, Ryota Inoue, Akiyoshi Sabu, Shingo Sakashita
  • Publication number: 20120064451
    Abstract: A carrier comprising a magnetic core particle having a shape factor SF-2 of 130 to 160 and a resin layer covering a surface of the magnetic core particle. The resin layer comprises a conductive particle and a resin obtained by heating a copolymer comprising a silicon-containing A unit and another silicon-containing B unit having.
    Type: Application
    Filed: September 6, 2011
    Publication date: March 15, 2012
    Inventors: Hiroyuki Kishida, Shigenori Yaguchi, Kimitoshi Yamaguchi, Toyoshi Sawada, Hiroshi Tohmatsu, Koichi Sakata, Hitoshi Iwatsuki, Toyoaki Tano, Mariko Takii
  • Publication number: 20120058423
    Abstract: A contact developing method including supplying a two-component developer to an electrostatic latent image on a rotating image bearing member by rotating a developing sleeve and a rotatable magnet having multiple magnetic poles provided inside the developing sleeve, to develop the electrostatic latent image into a toner image. The developing sleeve and the image bearing member rotate in the same direction while facing each other. The two-component developer comprises a non-magnetic toner and a carrier. The carrier comprises a magnetic core particle and a resin layer covering the magnetic core particle. The resin layer comprises a conductive particle and a resin. The conductive particle comprises an alumina-based material and a conductive layer covering the alumina-based material. The resin is obtained by heating a copolymer comprising a monomer A unit and a monomer B unit.
    Type: Application
    Filed: July 13, 2011
    Publication date: March 8, 2012
    Inventors: Kimitoshi Yamaguchi, Shigenori Yaguchi, Hitoshi Iwatsuki, Mariko Takii, Toyoshi Sawada, Toyoaki Tano, Hiroshi Tohmatsu, Koichi Sakata, Hiroyuki Kishida, Saori Yamada
  • Publication number: 20120057898
    Abstract: A carrier including a magnetic core particle and a resin layer covering a surface of the magnetic core particle. The magnetic core particle is a ferrite particle including strontium in an amount of 0.005 to 3% by mass, measured by fluorescent X-ray spectroscopy. The resin layer comprises a resin obtained by heating a copolymer comprising a silicon-containing unit A and another silicon-containing specific unit B.
    Type: Application
    Filed: August 19, 2011
    Publication date: March 8, 2012
    Inventors: Koichi Sakata, Shigenori Yaguchi, Toyoshi Sawada, Kimitoshi Yamaguchi, Hitoshi Iwatsuki, Hiroshi Tohmatsu, Hiroyuki Kishida, Toyoaki Tano, Mariko Takii
  • Publication number: 20110136051
    Abstract: A toner for use in developing an electrostatic latent image is provided. The toner includes a colored particulate material including at least a binder resin and a colorant; and an external additive present on a surface of the colored particulate material and including a particulate crystalline hydroxyapatite. The particulate crystalline hydroxyapatite has an average aspect ratio of not less than 3 and less than 30.
    Type: Application
    Filed: November 23, 2010
    Publication date: June 9, 2011
    Inventors: Masayuki Ishii, Toyoshi Sawada
  • Publication number: 20110129775
    Abstract: The present invention provides an image forming toner including at least a linear polyester resin (b1) as a binder resin, wherein the linear polyester resin (b1) is obtained by reacting a polyester diol (b11) having a polyhydroxycarboxylic acid skeleton, with a polyester diol (b12) other than the polyester diol (b11) in the presence of a chain extending agent.
    Type: Application
    Filed: June 17, 2009
    Publication date: June 2, 2011
    Inventors: Toyoshi Sawada, Akihiro Kotsugai, Akiyoshi Sabu
  • Patent number: 7824834
    Abstract: A toner including a binder resin; a colorant; a release agent; and a modified layered inorganic material in which at least part of interlayer ions is modified with an organic ion, wherein the toner has a volume average particle diameter (Dv) of 3 to 7 ?m and a ratio (Dv/Dn) of the volume average particle diameter (Dv) to a number average particle diameter (Dn) of the toner of 1.00 to 1.30, and wherein the release agent is included in the toner in an amount (A) of 1 to 10% by weight, and the ratio (B/A) of the amount (A) to the amount (B) of the release agent included in a classified toner in units of percent by weight is 0.7 to 1.3, wherein the classified toner satisfies the relationship (Dv?/Dn??1)/(Dv/Dn?1)?¾wherein Dv? and Dn? respectively represent the volume and number average particle diameters of the classified toner.
    Type: Grant
    Filed: September 14, 2007
    Date of Patent: November 2, 2010
    Assignee: Ricoh Company Limited
    Inventors: Junichi Awamura, Akinori Saitoh, Masahide Yamada, Toyoshi Sawada, Takuya Seshita, Tomomi Suzuki
  • Patent number: 7799498
    Abstract: The present invention provides an image forming apparatus capable of stably producing high quality images with time, without causing missing a central part of a thin line, however, with keeping an appropriate flowability of a toner. The toner used in the image forming apparatus is a toner which contains a binder resin, a colorant, and a laminar inorganic mineral in which at least part of an ion in layers is modified with an organic ion, the toner is granulated in an aqueous system, the volume average particle diameter Dv of the toner is in the range of 3.0 ?m<Dv<6.5 ?m, the aspect ratio of the toner is 0.81 to 0.89, and the surface of the toner is externally added with a plurality of types of fine particles.
    Type: Grant
    Filed: February 6, 2008
    Date of Patent: September 21, 2010
    Assignee: Ricoh Company, Ltd.
    Inventors: Takuya Seshita, Junichi Awamura, Tomomi Suzuki, Toyoshi Sawada, Masahide Yamada
  • Publication number: 20100216068
    Abstract: A toner including a colorant, a thermoplastic resin (a) comprising an amorphous polyester resin having a main chain having a polyhydroxycarboxylic acid skeleton, and a thermoplastic resin (b) is provided. The toner is manufactured by a method including mixing the colorant with the thermoplastic resin (a) to prepare a preliminary mixture, and mixing the preliminary mixture with the thermoplastic resin (b).
    Type: Application
    Filed: February 26, 2010
    Publication date: August 26, 2010
    Inventors: Akihiro KOTSUGAI, Toyoshi Sawada, Ryota Inoue, Akiyoshi Sabu, Shingo Sakashita, Keiko Osaka, Yukiko Nakajima
  • Publication number: 20100119255
    Abstract: An image forming apparatus including an image bearer; a charging device charging the image bearer; a light irradiating device irradiating the charged image bearer with light to form an electrostatic image; a developing device developing the electrostatic image with a developer including a toner to form a toner image on the image bearer; a transfer device transferring the toner image; and a cleaning device cleaning the image bearer, wherein the volume average particle diameter of the toner is greater than 5.0 ?m and less than 5.5 ?m, the content of toner particles having a particle diameter of not greater than 4.0 ?m is not higher than 20% by number, the ratio of the first shape factor SF-1 to the second shape factor SF-2 is from 1.00 to 1.15, and the content of toner particles having a SF-2 of not less than 115 is not less than 67.
    Type: Application
    Filed: January 19, 2010
    Publication date: May 13, 2010
    Inventors: Takuya SESHITA, Toyoshi SAWADA, Tomomi SUZUKI, Tsuneyasu NAGATOMO, Satoshi KOJIMA
  • Publication number: 20100104965
    Abstract: The toner includes a binder resin; a release agent; a colorant; and a dispersing resin configured to disperse the release agent. The dispersing resin includes a polyhydroxycarboxylic acid unit obtained from an optically active monomer. The polyhydroxycarboxylic acid unit has an optical purity of not greater than 80%, wherein the optical purity is defined as the absolute value of difference between the mole percentage of a L-monomer in the optically active monomer and the mole percentage of a D-monomer in the optically active monomer.
    Type: Application
    Filed: October 8, 2009
    Publication date: April 29, 2010
    Inventors: Ryota INOUE, Akihiro Kotsugai, Toyoshi Sawada, Akiyoshi Sabu
  • Patent number: 7695878
    Abstract: An image forming apparatus including an image bearer; a charging device charging the image bearer; a light irradiating device irradiating the charged image bearer with light to form an electrostatic image; a developing device developing the electrostatic image with a developer including a toner to form a toner image on the image bearer; a transfer device transferring the toner image; and a cleaning device cleaning the image bearer, wherein the volume average particle diameter of the toner is greater than 5.0 ?m and less than 5.5 ?m, the content of toner particles having a particle diameter of not greater than 4.0 ?m is not higher than 20% by number, the ratio of the first shape factor SF-1 to the second shape factor SF-2 is from 1.00 to 1.15, and the content of toner particles having a SF-2 of not less than 115 is not less than 67.8% by number.
    Type: Grant
    Filed: March 16, 2007
    Date of Patent: April 13, 2010
    Assignee: Ricoh Company Limited
    Inventors: Takuya Seshita, Toyoshi Sawada, Tomomi Suzuki, Tsuneyasu Nagatomo, Satoshi Kojima
  • Publication number: 20100061759
    Abstract: A carrier for electrophotographic developer, including a core material; and a layer comprising a binder resin, located overlying the core material, wherein the binder resin includes a segment including one or more polymerizable vinyl monomers as a structural unit; and another segment including a partial cleavage structure of polyhedral oligomeric silsesquioxane and/or another partial cleavage structure of polyhedral oligomeric silsesquloxane as a structural unit.
    Type: Application
    Filed: September 8, 2009
    Publication date: March 11, 2010
    Applicant: RICOH COMPANY, LTD.
    Inventors: Yoshihiro MORIYA, Akihiro Kotsugai, Toyoshi Sawada, Ryota Inoue, Akiyoshi Sabu, Shingo Sakashita
  • Patent number: 7550243
    Abstract: The object of the present invention is to provide a toner characterized in that the toner comprises a first binder resin and a second binder resin, the first binder resin is an amorphous resin and the second binder resin is a crystalline resin, and the glass-transition temperature of the toner (TgA) is lower than the glass-transition temperature expressed by the following equation (1) (TgC). TgC = ? i = 1 n ? ? b i / ? i = 1 n ? ? ( b i TgB i ) Equation ? ? ( 1 ) In the above equation (1), “TgBi” represents the glass-transition temperature of the amorphous resin, “n” represents the number of amorphous resins, and “b” represents the content of the amorphous resin (part by mass). Examples of the preferred aspect of the present invention includes the one that at least a part of the amorphous resin and a part of the crystalline resin are compatible each other, and the one that the glass-transition temperature of the toner (TgA) is 10° C.
    Type: Grant
    Filed: June 17, 2008
    Date of Patent: June 23, 2009
    Assignee: Ricoh Company, Ltd.
    Inventors: Keiko Matsumoto, Toyoshi Sawada
  • Publication number: 20090142093
    Abstract: An image forming toner, including a mother particle including a paraffin wax having a melting point of from 60 to 90° C. and a binder resin, wherein the mother particle has an endothermic peak of the paraffin wax of from 2.0 J/g to 5.5 J/g when measured by a DSC and an aspect ratio of from 0.8 to 0.90.
    Type: Application
    Filed: October 29, 2008
    Publication date: June 4, 2009
    Inventors: Toyoshi SAWADA, Tomomi Suzuki, Tsuneyasu Nagatomo, Satoshi Kojima
  • Publication number: 20090142686
    Abstract: To provide an image forming method including conveying a toner by means of a toner supply device that supplies the toner from inside a toner housing container into a developer housing section of a developing device with the use of a screw pump, and forming an image on a recording medium by developing a latent image on a latent image bearing member to form a toner image with the use of a developer and by transferring the toner image to the recording medium by means of a transfer device, wherein the toner is formed by adding small particle size silica to toner base particles, and wherein when A represents the average degree of circularity of the toner, and B, expressed as percent by mass, represents the amount of the small particle size silica relative to the mass of the toner base particles, the expression ?18A+17.92?B??34A+33.96 is satisfied.
    Type: Application
    Filed: November 19, 2008
    Publication date: June 4, 2009
    Inventors: Satoshi KOJIMA, Toyoshi Sawada, Tsuneyasu Nagatomo
  • Publication number: 20090142685
    Abstract: An image forming method including charging an image bearing member by applying combination of DC voltage and AC voltage with frequency of 6.5 to 8.5 cycle/mm; irradiating the image bearing member with light to form an electrostatic image; developing the electrostatic image with a developer including toner to form a toner image; transferring the toner image onto a receiving material; fixing the toner image; cleaning the image bearing member with a blade; then applying a lubricant to the image bearing member; and then spreading the lubricant with a spreading member countering the image bearing member. The toner includes toner particles granulated in an aqueous medium; and at least three kinds of external additives including a first particulate hydrophobic silica, a particulate hydrophobic titanium oxide and a second particulate hydrophobic silica respectively having BET specific surface areas of 20 to 40 m2/g, 40 to 80 m2/g, and 130 to 300 m2/g.
    Type: Application
    Filed: November 24, 2008
    Publication date: June 4, 2009
    Inventors: Tsuneyasu NAGATOMO, Toyoshi Sawada, Satoshi Kojima
  • Publication number: 20090142094
    Abstract: A toner including a binder resin and a colorant which produces a torque of from 1.4 to 2.0 mNm, when a cone rotor having a vertical angle of 60° and grooves on a surface thereof intrudes into a bulk of the toner at an intrusion speed of 5 mm/min for a depth of 20 mm while rotating at a rotation speed of 1 rpm. The bulk of the toner is formed by consolidating 30 g of the toner in a cylindrical container having an internal diameter of 60 mm for 60 seconds with a consolidation load of 585 g.
    Type: Application
    Filed: November 14, 2008
    Publication date: June 4, 2009
    Inventors: Toyoshi Sawada, Tomomi Suzuki, Tsuneyasu Nagatomo, Takuya Seshita, Satoshi Kojima, Junichi Awamura
  • Publication number: 20090067876
    Abstract: An image forming method, including charging the surface of an image bearer with a charger; irradiating the charged surface of the image bearer to form a latent image; developing the latent image with a toner to form a visible toner image; transferring the toner image onto a transfer medium directly or through an intermediate transferer; removing the toner remaining on the surface of the image bearer with a cleaning blade; applying a lubricant to the surface of the image bearer; and fixing the toner image on the transfer medium, wherein the toner is a water-granulated toner having the following properties (1) to (4): (1) a volume-average particle diameter of from 3.0 to 7.0 ?m; (2) an average shape factor SF-1 of from 120 to 160; (3) an average shape factor SF-2 of from 100 to 140; and (4) a BET specific surface area of from 2.5 to 7.0 m2/g.
    Type: Application
    Filed: September 2, 2008
    Publication date: March 12, 2009
    Inventors: Takuya SESHITA, Toyoshi Sawada, Tomomi Suzuki, Tsuneyasu Nagatomo, Satoshi Kojima
  • Publication number: 20080292361
    Abstract: The present invention provides an image forming apparatus capable of stably producing high quality images with time, without causing missing a central part of a thin line, however, with keeping an appropriate flowability of a toner. The toner used in the image forming apparatus is a toner which contains a binder resin, a colorant, and a laminar inorganic mineral in which at least part of an ion in layers is modified with an organic ion, the toner is granulated in an aqueous system, the volume average particle diameter Dv of the toner is in the range of 3.0 ?m<Dv<6.5 ?m, the aspect ratio of the toner is 0.81 to 0.89, and the surface of the toner is externally added with a plurality of types of fine particles.
    Type: Application
    Filed: February 6, 2008
    Publication date: November 27, 2008
    Inventors: Takuya SESHITA, Junichi Awamura, Tomomi Suzuki, Toyoshi Sawada, Masahide Yamada