Patents by Inventor Yukiko Nakajima

Yukiko Nakajima 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: 8883385
    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: Grant
    Filed: December 5, 2012
    Date of Patent: November 11, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Shingo Sakashita, Hiroshi Yamashita, Masahide Yamada, Shinya Nakayama, Atsushi Yamamoto, Yukiko Nakajima
  • Patent number: 8877415
    Abstract: A toner including a resin particle (C) is provided. The resin particle (C) includes a resin particle (B) and; a resin particle (A) or covering layer (P) that is adhered to a surface of the resin particle (B). The resin particle (B) includes a resin (b) having a polyhydroxycarboxylic acid skeleton. The resin particle (A) or covering layer (P) includes a resin (a). The resin (a) is a polyester resin having a polybasic acid unit and a polyol unit and has a weight average molecular weight within a range from 9,500 to 100,000.
    Type: Grant
    Filed: February 6, 2013
    Date of Patent: November 4, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Daiki Yamashita, Shinya Nakayama, Atsushi Yamamoto, Yukiko Nakajima, Akiyoshi Sabu, Yoshihiro Moriya, Hideyuki Santo
  • Patent number: 8865384
    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: Grant
    Filed: March 8, 2013
    Date of Patent: October 21, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Masahide Yamada, Shinya Nakayama, Atsushi Yamamoto, Hideyuki Santo, Shingo Sakashita, Yukiko Nakajima, Suzuka Amemori, Akiyoshi Sabu
  • Patent number: 8859179
    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: Grant
    Filed: November 16, 2012
    Date of Patent: October 14, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Hideyuki Santo, Masahide Yamada, Kazumi Suzuki, Shinya Nakayama, Atsushi Yamamoto, Tatsuya Morita, Shingo Sakashita, Yukiko Nakajima, Keiji Makabe, Daiki Yamashita
  • Publication number: 20140301757
    Abstract: A toner including at least a crystalline resin as a binder resin, wherein a tetrahydrofuran soluble content of the toner includes 5.0% or more as a peak area of a component having a molecular weight of 100,000 or greater in a molecular weight distribution measured by gel permeation chromatography, and the tetrahydrofuran soluble content of the toner has a weight-average molecular weight of 20,000 to 60,000.
    Type: Application
    Filed: October 17, 2012
    Publication date: October 9, 2014
    Inventors: Shingo Sakashita, Shinya Nakayama, Masahide Yamada, Atsushi Yamamoto, Hideyuki Santo, Yukiko Nakajima, Suzuka Amemori
  • Patent number: 8828635
    Abstract: A toner including a resin particle (C) is provided. The resin particle (C) includes a resin particle (B) and a resin particle (A). The resin particle (B) includes a resin (b). The resin particle (A) or covering layer (P) includes a resin (a). The resin particle (A) or covering layer (P) is adhered to a surface of the resin particle (B). The resin (a) is a polyester resin. The resin (a) has a total acid value of 15 to 36 mgKOH/g. The resin particle (A) or covering layer (P) has a surface acid value of 10 to 27 mgKOH/g.
    Type: Grant
    Filed: August 2, 2012
    Date of Patent: September 9, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoshihiro Moriya, Shinya Nakayama, Atsushi Yamamoto, Hideyuki Santo, Akiyoshi Sabu, Yukiko Nakajima, Daiki Yamashita
  • Patent number: 8735040
    Abstract: To provide a toner including at least a binder resin and a colorant, wherein the binder resin has two glass transition temperatures Tg1 and Tg2 in a differential scanning calorimetry at a heating speed of 5° C./min, the glass transition temperature Tg1 is ?20° C. to 20° C., and the glass transition temperature Tg2 is 35° C. to 65° C., wherein the binder resin comprises a polyester skeleton and a ring-containing skeleton molecule at ends thereof, and wherein the binder resin is obtained by block copolymerization of: a polyester skeleton A which includes a structural unit obtained by dehydration condensation of a hydroxycarboxylic acid in a repeating structure; and a skeleton B which does not include a structural unit obtained by dehydration condensation of a hydroxycarboxylic acid in a repeating structure.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: May 27, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Suzuka Amemori, Masahide Yamada, Yoshihiro Moriya, Taichi Nemoto, Yukiko Nakajima, Yoshitaka Yamauchi, Daiki Yamashita, Keiji Makabe, Akiyoshi Sabu
  • Patent number: 8691486
    Abstract: An electrostatic image developing toner including a toner particle (C), wherein the toner particle (C) has a structure in which a resin particle (A) containing at least a first resin (a) or a coated film (P) containing the first resin (a) is attached to a surface of a resin-containing particle (B) containing a second resin (b), and wherein the resin (b) includes a polyhydroxycarboxylic acid skeleton, and the resin (a) is a polyester resin containing a polybasic acid and a polyhydric alcohol.
    Type: Grant
    Filed: June 28, 2010
    Date of Patent: April 8, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Akihiro Kotsugai, Akiyoshi Sabu, Shingo Sakashita, Yukiko Nakajima, Keiko Osaka
  • Patent number: 8685604
    Abstract: A toner including a colorant and a first binder resin is provided. The first binder resin has first and second glass transition points at a temperature Tg1 of ?20 to 20° C. and a temperature Tg2 of 35 to 65° C., respectively, measured by a differential scanning calorimeter at a heating rate of 5° C./min. A ratio h1/h2 of a baseline displacement h1 observed in the first glass transition point to a baseline displacement h2 observed in the second glass transition point is less than 1.0. The first binder resin has a structure in which a first phase is dispersed in a second phase. The first and second phases consist of portions having larger and smaller phase difference values, respectively, than an intermediate value between maximum and minimum phase difference values in a binarized phase image obtained by an atomic force microscope with a tapping mode method.
    Type: Grant
    Filed: September 11, 2012
    Date of Patent: April 1, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoshihiro Moriya, Masahide Yamada, Taichi Nemoto, Yukiko Nakajima, Yoshitaka Yamauchi, Daiki Yamashita, Keiji Makabe, Akiyoshi Sabu, Suzuka Amemori
  • Patent number: 8679714
    Abstract: A toner including: a first binder resin; a colorant; a releasing agent; and a crystalline organic compound, wherein the first binder resin contains an amorphous polyester resin (a) having a polyhydroxycarboxylic acid skeleton derived from optically active monomers in a part of a main chain of the amorphous polyester resin, and the polyhydroxycarboxylic acid skeleton has an optical purity X, calculated on the monomer basis, of 80% or less, and the optical purity X is determined from the equation, Optical Purity X (%)=|X(L-form)?X(D-form)| wherein the crystalline organic compound is any one of a crystalline polyester resin (b) and a crystalline low molecular compound having a melting point of 60° C. to 100° C., and being selected from a group consisting of fatty acid having 16 to 24 carbon atoms, alcohol having 16 to 24 carbon atoms, a fatty acid ester compound, and aliphatic carboxylic acid amide.
    Type: Grant
    Filed: September 9, 2010
    Date of Patent: March 25, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Ryota Inoue, Akihiro Kotsugai, Yoshihiro Moriya, Akiyoshi Sabu, Shingo Sakashita, Keiko Osaka, Yukiko Nakajima, Yoshitaka Yamauchi, Daiki Yamashita
  • Publication number: 20140065534
    Abstract: A toner, including: a crystalline resin containing a urethane bond, a urea bond, or both thereof; and a compound represented by the following General Formula (1), wherein an amount of the compound represented by the General Formula (1) is 0.01% by mass to 0.25% by mass: CnH2n+1R??General Formula (1) where n is 8 to 22 and R is COOH, NH2 or OH.
    Type: Application
    Filed: August 29, 2013
    Publication date: March 6, 2014
    Inventors: Suzuka AMEMORI, Atsushi Yamamoto, Masahide Yamada, Yukiko Nakajima, Shinya Nakayama, Hideyuki Santo
  • Patent number: 8663888
    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: Grant
    Filed: December 20, 2010
    Date of Patent: March 4, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Yasutada Shitara, Yohichiroh Watanabe, Yasuo Katano, Shinya Nakayama, Ryota Inoue, Yoshihiro Moriya, Akiyoshi Sabu, Shingo Sakashita, Yukiko Nakajima
  • Patent number: 8658340
    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: Grant
    Filed: May 9, 2011
    Date of Patent: February 25, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Shingo Sakashita, Shinya Nakayama, Ryota Inoue, Yoshihiro Moriya, Akiyoshi Sabu, Yukiko Nakajima, Daiki Yamashita
  • Patent number: 8632932
    Abstract: A toner including a binder resin comprising a resin (a) comprising a polyhydroxycarboxylic acid skeleton formed from an optically-active monomer. The polyhydroxycarboxylic acid skeleton has a weight average molecular weight of from 7,000 to 60,000. The binder resin comprises the polyhydroxycarboxylic acid skeleton in an amount of from 10 to 90% by weight. The optical purity X (%) of the polyhydroxycarboxylic acid skeleton represented by the following formula is 80% or less: X(%)=|X(L-isomer)?X(D-isomer)| wherein X(L-isomer) and X(D-isomer) represent molar ratio (%) of L-isomer and D-isomer of the optically-active monomer, respectively.
    Type: Grant
    Filed: December 30, 2009
    Date of Patent: January 21, 2014
    Assignee: Ricoh Company, Limited
    Inventors: Akiyoshi Sabu, Akihiro Kotsugai, Ryota Inoue, Keiko Osaka, Shingo Sakashita, Yukiko Nakajima, Satoshi Mochizuki
  • Patent number: 8623580
    Abstract: To provide a toner including: a resin particle (C) containing a first resin (a1), a second resin (a2), and a resin particle (B) to a surface of which the first resin (a1) and the second resin (a2) are attached, wherein the first resin (a1) and the second resin (a2) have mutually different glass transition temperatures, and wherein the resin particle (B) contains a third resin (b) having an amorphous polyhydroxycarboxylic acid skeleton.
    Type: Grant
    Filed: August 3, 2010
    Date of Patent: January 7, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Yukiko Nakajima, Akihiro Kotsugai, Ryota Inoue, Akiyoshi Sabu, Shingo Sakashita, Keiko Osaka
  • 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
  • Publication number: 20130260298
    Abstract: A toner including: a binder resin; and a colorant, wherein the toner is obtained by dispersing or emulsifying an oil phase in an aqueous solvent containing an organic sulfonic acid salt and an inorganic salt, the oil phase including the binder resin and the colorant dissolved or dispersed in an organic solvent, wherein the binder resin comprises a crystalline resin in an amount of 50% by mass or more relative to the binder resin, and wherein the toner has an average circularity of 0.980 or less.
    Type: Application
    Filed: March 8, 2013
    Publication date: October 3, 2013
    Inventors: Suzuka AMEMORI, Masahide YAMADA, Shinya NAKAYAMA, Yukiko NAKAJIMA
  • 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: 20130244168
    Abstract: A toner including a resin particle (C) is provided. The resin particle (C) includes a resin particle (B) and; a resin particle (A) or covering layer (P) that is adhered to a surface of the resin particle (B). The resin particle (B) includes a resin (b) having a polyhydroxycarboxylic acid skeleton. The resin particle (A) or covering layer (P) includes a resin (a). The resin (a) is a polyester resin having a polybasic acid unit and a polyol unit and has a weight average molecular weight within a range from 9,500 to 100,000.
    Type: Application
    Filed: February 6, 2013
    Publication date: September 19, 2013
    Inventors: Daiki YAMASHITA, Shinya Nakayama, Atsushi Yamamoto, Yukiko Nakajima, Akiyoshi Sabu, Yoshihiro Moriya, Hideyuki Santo
  • Publication number: 20130244167
    Abstract: A toner including a binder resin having a glass transition temperature (Tg) observed at least at one point from 25 to 65° C. in a differential scanning calorimeter at a rate of temperature increase of 5° C./min, wherein the toner has a structure in which a structure appearing as a high phase difference image is dispersed in a structure appearing as a low phase difference image in a two-dimensional phase difference image observed by tapping mode AFM, and an X-ray diffraction chart in which a peak originated from an crystalline resin is observed in a range of a diffraction angle 2? of from 20 to 25°, and wherein a ratio (I1/I2) of an intensity of the peak originated from an crystalline resin to an intensity (I2) of a halo originated from an amorphous composition is from 0.2 to 1.
    Type: Application
    Filed: January 31, 2013
    Publication date: September 19, 2013
    Inventors: Daiki YAMASHITA, Yoshihiro Moriya, Yukiko Nakajima, Taichi Nemoto, Yoshitaka Yamauchi, Keiji Makabe, Masahide Yamada, Suzuka Amemori