Patents by Inventor Shingo Sakashita

Shingo Sakashita 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: 8603713
    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: Grant
    Filed: February 26, 2010
    Date of Patent: December 10, 2013
    Assignee: Ricoh Company, Limited
    Inventors: Akihiro Kotsugai, Toyoshi Sawada, Ryota Inoue, Akiyoshi Sabu, Shingo Sakashita, Keiko Osaka, Yukiko Nakajima
  • Patent number: 8592118
    Abstract: In accordance with some embodiments, a toner including a first binder resin, a release agent, a release agent dispersing resin, and a colorant is provided. The first binder resin includes an amorphous polyester resin (a) having a polyhydroxycarboxylic acid skeleton in its main chain. The polyhydroxycarboxylic acid skeleton comprises optically-active monomers having an optical purity X of 80% by mole or less. The optical purity X is represented by the following formula: X(% by mole)=|X(L-form)?X(D-form)| wherein X(L-form) and X(D-form) represent ratios (% by mole) of L-form and D-form optically-active monomers, respectively. The release agent includes an ester of a fatty acid having an average carbon number of 18 to 24 with glycerin or a polyglycerin having an average polymerization degree of 2 to 10. The ester has a melting point of 55 to 80° C.
    Type: Grant
    Filed: April 26, 2012
    Date of Patent: November 26, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Shingo Sakashita, Kazumi Suzuki, Tatsuya Morita
  • Publication number: 20130252158
    Abstract: An electrophotographic toner, including: a binder resin; a colorant; and an organically-modified layered inorganic mineral, wherein the binder resin contains 50% by mass or more of a crystalline resin relative to the binder resin, and the crystalline resin contains a resin having a sulfonic acid group, and wherein an amount of the sulfonic acid group is 0.1% by mass to 2.0% by mass relative to the resin having the sulfonic acid group.
    Type: Application
    Filed: March 8, 2013
    Publication date: September 26, 2013
    Inventors: Masahide YAMADA, Shinya NAKAYAMA, Atsushi YAMAMOTO, Hideyuki SANTO, Shingo SAKASHITA, Yukiko NAKAJIMA, Suzuka AMEMORI, Akiyoshi SABU
  • Publication number: 20130244154
    Abstract: Toner containing a binder resin that contains at least one kind of resin having a crystalline polyester unit as its main component and a releasing agent containing a straight-chain mono ester having 48 or more carbon atoms accounting for 40% by weight or more of the releasing agent.
    Type: Application
    Filed: March 4, 2013
    Publication date: September 19, 2013
    Inventors: Atsushi YAMAMOTO, Shinya NAKAYAMA, Hideyuki SANTO, Suzuka AMEMORI, Shingo SAKASHITA, Masahide YAMADA
  • Publication number: 20130236826
    Abstract: A toner for electrophotography, which is prepared by a method including dissolving or dispersing a toner composition including at least a binder resin, or binder resin and a binder resin precursor as a resin component; and a colorant in an organic solvent to form an oil phase; emulsifying or dispersing the oil phase in an aqueous medium to form an emulsion dispersion comprising emulsified particles; converging the emulsified particles to granulate mother toner particles, including controlling a temperature of the emulsion dispersion to control a circularity of the mother toner particles; and removing the organic solvent, wherein the resin component includes a crystalline resin in an amount not less than 50% by weight, and the mother toner particles have an average circularity of from 0.940 to 0.980.
    Type: Application
    Filed: December 10, 2012
    Publication date: September 12, 2013
    Inventors: Keiji MAKABE, Masahide Yamada, Shinya Nakayama, Atsushi Yamamoto, Hideyuki Santo, Yukiko Nakajima, Daiki Yamashita, Kazumi Suzuki, Tatsuya Morita, Shingo Sakashita
  • Publication number: 20130196263
    Abstract: An electrostatic image forming toner including: toner base particles each containing at least a colorant, a binder resin, and a releasing agent, wherein the binder resin contains a non-crystalline polyester resin A and a crystalline polyester resin B, wherein a ratio of B/(A+B)×100 is 10 or more but less than 50 where (A+B) is a total mass of the non-crystalline polyester resin A and the crystalline polyester resin B and “B” is a mass of the crystalline polyester resin B, and wherein the toner base particles have a TMA compression deformation amount (TMA %) of 10% or less which is measured at 50° C. and a relative humidity of 90%.
    Type: Application
    Filed: January 28, 2013
    Publication date: August 1, 2013
    Inventors: Daisuke Asahina, Tsuyoshi Sugimoto, Rintaro Takahashi, Hiroshi Yamashita, Taichi Nemoto, Shingo Sakashita, Yoshitaka Yamauchi, Satoyuki Sekiguchi
  • Publication number: 20130157183
    Abstract: A developer, including a toner including a binder resin comprising a crystalline resin; and a colorant, and a resin carrier comprising a resin; a magnetic particulate material having a magnetic anisotropy, dispersed in the resin, and having a saturated magnetization of from 16 to 30 emu/g, a coercive force of from 15 to 40 kA/m and an average particle diameter not less than 15 ?m and less than 100 ?m.
    Type: Application
    Filed: November 16, 2012
    Publication date: June 20, 2013
    Inventors: Hideyuki Santo, Masahide Yamada, Kazumi Suzuki, Shinya Nakayama, Atsushi Yamamoto, Tatsuya Morita, Shingo Sakashita, Yukiko Nakajima, Keiji Makabe, Daiki Yamashita
  • Publication number: 20130157184
    Abstract: To provide a toner, including at least: a non-crystalline polyester resin; and a crystalline polyester resin, wherein the toner has a glass transition temperature in a first heating Tg1st and a glass transition temperature in a second heating Tg2nd, and a difference between Tg1st and Tg2nd (Tg1st?Tg2nd) is 10° C. or greater, and wherein the crystalline polyester resin is a modified crystalline polyester resin having a urethane skeleton or a urea skeleton, or both thereof.
    Type: Application
    Filed: November 26, 2012
    Publication date: June 20, 2013
    Inventors: Tsuyoshi SUGIMOTO, Hiroshi Yamashita, Daisuke Asahina, Rintaro Takahashi, Masahide Yamada, Shinya Nakayama, Atsushi Yamamoto, Shingo Sakashita
  • Publication number: 20130157185
    Abstract: A toner includes a binder resin, a coloring agent, and a releasing agent containing two or more kinds of alkyl monoester compounds having a different number of carbon atoms in a range of from 30 to 50 carbon atoms. The toner has a crystallinity of 10% or more as measured by x-ray diffraction and/or the binder resin is a crystalline resin in an amount of 50% by weight or more of the binder resin. The two or more kinds of alkyl monoester compounds include a component A accounting for the largest amount ranging from 30% by weight to less than 50% by weight of the releasing agent and a component B accounting for the second largest amount ranging from 10% by weight to less than 50% by weight of the releasing agent.
    Type: Application
    Filed: December 5, 2012
    Publication date: June 20, 2013
    Inventors: Shingo SAKASHITA, Hiroshi Yamashita, Masahide Yamada, Shinya Nakayama, Atsushi Yamamoto, Yukiko Nakajima
  • Publication number: 20130017480
    Abstract: A toner set for electrophotography, including a black toner; a yellow toner; a magenta toner; a cyan toner; and a bright yellow toner, wherein the magenta toner includes a magenta colorant mainly including C.I. Pigment Red 122, the yellow toner has a hue angle of from 93 to 100° and the bright yellow toner has a hue angle of from 60 to 85° in L*a*b* color system.
    Type: Application
    Filed: June 19, 2012
    Publication date: January 17, 2013
    Inventors: Kazumi SUZUKI, Tatsuya MORITA, Shingo SAKASHITA
  • Patent number: 8329374
    Abstract: There is provided a method for producing a carrier, which includes depositing a resin coating layer on the surface of a magnetic material; adding a treatment agent for a conductor precursor to the resin coating layer so as to treat the resin coating layer with the treatment agent; and exposing the treatment agent-added resin coating layer to a conductor precursor in a supercritical or subcritical fluid so as to form a conductor in the resin coating layer.
    Type: Grant
    Filed: December 31, 2008
    Date of Patent: December 11, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Akihiro Kotsugai, Yoshihiro Moriya, Shingo Sakashita
  • Publication number: 20120288791
    Abstract: In accordance with some embodiments, a toner including a first binder resin, a release agent, a release agent dispersing resin, and a colorant is provided. The first binder resin includes an amorphous polyester resin (a) having a polyhydroxycarboxylic acid skeleton in its main chain. The polyhydroxycarboxylic acid skeleton comprises optically-active monomers having an optical purity X of 80% by mole or less. The optical purity X is represented by the following formula: X (% by mole)=|X(L-form)?X(D-form)| wherein X(L-form) and X(D-form) represent ratios (% by mole) of L-form and D-form optically-active monomers, respectively. The release agent includes an ester of a fatty acid having an average carbon number of 18 to 24 with glycerin or a polyglycerin having an average polymerization degree of 2 to 10. The ester has a melting point of 55 to 80° C.
    Type: Application
    Filed: April 26, 2012
    Publication date: November 15, 2012
    Inventors: Shingo Sakashita, Kazumi Suzuki, Tatsuya Morita
  • 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: 20120202147
    Abstract: An anisotropic magnetic material-dispersed resin carrier including: fine magnetic particles; and a binder resin in which at least the fine magnetic particles are dispersed, wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the fine magnetic particles are orientated in the same direction, and wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 ?m or more but less than 100 ?m.
    Type: Application
    Filed: January 31, 2012
    Publication date: August 9, 2012
    Applicant: RICOH COMPANY, LTD.
    Inventors: Kazumi SUZUKI, Masaki Yoshino, Hisao Kurosu, Tatsuya Morita, Tomoko Kino, Shingo Sakashita
  • Publication number: 20120082926
    Abstract: A toner comprising an amorphous polyester, a crystalline polyester that is forming domains in the toner, and a colorant that is being dispersed at least in the domains of the crystalline polyester. The toner may be obtained by dispersing an oil phase including the amorphous polyester or a precursor capable of producing the amorphous polyester, the crystalline polyester, the colorant, and an organic solvent, in an aqueous medium to prepare an O/W dispersion, the oil phase; and removing the organic solvent from the O/W dispersion.
    Type: Application
    Filed: September 20, 2011
    Publication date: April 5, 2012
    Inventors: Kazumi SUZUKI, Tatsuya MORITA, Shingo SAKASHITA, Tsuyoshi SUGIMOTO
  • Patent number: 8105743
    Abstract: The present invention provides an organic silicone fine particle for latent electrostatic image developing toners, wherein the organic silicone fine particle has a volume average particle diameter of 0.05 ?m to 6.0 ?m which is obtained by measurement based on Coulter principle, and has a hemispherical polysiloxane cross-linked structure. By mixing an appropriate amount of an organic silicone resin particle formed in a deformed shape (a hemispherical shape) in a toner or developer, the present invention prevents movement of the organic silicone resin particle from surface functional sites, the movement caused by a phenomenon such as detachment thereof from a toner surface or rolling movement on the toner surface, by the effect of its shape, and makes it possible to effectively achieve the expected function.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: January 31, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Masayuki Ishii, Ryota Inoue, Yoshihiro Moriya, Shingo Sakashita
  • Patent number: 8084181
    Abstract: To provide a method for producing a carrier including treating a coating layer on a surface of a core material with a polymer precursor in a supercritical fluid and/or a subcritical fluid so as to add the polymer precursor to the coating layer, and subjecting the coating layer to oxidation treatment so as to form a polymer from the polymer precursor in the coating layer, and a carrier produced by the method.
    Type: Grant
    Filed: April 30, 2008
    Date of Patent: December 27, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Masayuki Ishii, Yoshihiro Moriya, Takuya Seshita, Shingo Sakashita, Chiaki Tanaka
  • Publication number: 20110281213
    Abstract: A toner containing a binder resin comprising a first binder resin A and a second binder resin B, a coloring agent, and a releasing agent, wherein the first binder resin A is formed by reacting a compound A1 having an active hydrogen group with a resin A2 having a portion reactive with the compound A1 in an organic solvent and the resin A2 is formed by reacting a non-crystalline polyester resin “a” having a polyhydroxy carboxylic acid skeleton in the main chain with a compound having the portion reactive with the compound A1 having an active hydrogen group.
    Type: Application
    Filed: May 9, 2011
    Publication date: November 17, 2011
    Inventors: Shingo SAKASHITA, Shinya Nakayama, Ryota Inoue, Yoshihiro Moriya, Akiyoshi Sabu, Yukiko Nakajima, Daiki Yamashita
  • Patent number: 8043785
    Abstract: The present invention provides a method for producing a carrier that includes dissolving at least a coating material in carbon dioxide in a liquid state, and forming a coating layer on a core material surface by reducing the solubility of the liquid with at least the coating material dissolved therein through control of at least any one of the pressure and temperature. The present invention also provides a carrier produced by the method for producing a carrier.
    Type: Grant
    Filed: November 23, 2007
    Date of Patent: October 25, 2011
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Chiaki Tanaka, Masayuki Ishii, Yoshihiro Moriya, Shingo Sakashita
  • Publication number: 20110151370
    Abstract: The present invention provides a toner including: a colorant, and a binder resin, wherein the toner is fixed on a recording medium using a fixing liquid containing a softening agent for softening the toner, and wherein a weight average molecular weight of a THF soluble fraction of the toner in a molecular weight distribution measured by gel permeation chromatography (GPC) is 3,000 to 8,300; and a glass transition temperature of the toner measured by differential scanning calorimetry (DSC) is 50° C. to 70° C.
    Type: Application
    Filed: December 20, 2010
    Publication date: June 23, 2011
    Inventors: Yasutada SHITARA, Yohichiroh Watanabe, Yasuo Katano, Shinya Nakayama, Ryota Inoue, Yoshihiro Moriya, Akiyoshi Sabu, Shingo Sakashita, Yukiko Nakajima