Patents by Inventor Akiyoshi Sabu

Akiyoshi Sabu 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: 8741520
    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: Grant
    Filed: June 17, 2009
    Date of Patent: June 3, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Toyoshi Sawada, Akihiro Kotsugai, Akiyoshi Sabu
  • 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
  • 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: 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: 20130244011
    Abstract: A colorless transparent toner containing a crystalline resin having a urethane bond and/or a urea bond.
    Type: Application
    Filed: February 4, 2013
    Publication date: September 19, 2013
    Inventors: Akiyoshi SABU, Shinya NAKAYAMA, Atsushi YAMAMOTO, Yukiko NAKAJIMA, Hideyuki SANTO
  • Publication number: 20130202996
    Abstract: The toner includes a pigment; and a block copolymer having a polyester block A including a residual group of a hydroxycarboxylic acid, and a polyester block B including an anionic group. When cross-section of the block copolymer is observed by a tapping mode atomic force microscope to obtain a phase image of the cross-section, the polyester block B, which has relatively large phase delay, is dispersed as domains having an average size of from 20 nm to 100 nm in a domain of the polyester block A, which has relatively small phase delay. The block copolymer has a first glass transition temperature of from ?20° C. to 20° C., and a second glass transition temperature of from 35° C. to 65° C. when the first and second glass transition temperatures are determined from a thermogram obtained by subjecting the block copolymer to differential scanning calorimetry (DSC) at a temperature rising speed of 5° C./min.
    Type: Application
    Filed: December 17, 2012
    Publication date: August 8, 2013
    Inventors: Yoshitaka Yamauchi, Masahide Yamada, Yoshihiro Moriya, Taichi Nemoto, Yukiko Nakajima, Keiji Makabe, Daiki Yamashita, Suzuka Amemori, Akiyoshi Sabu
  • Publication number: 20130171550
    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: Application
    Filed: December 27, 2012
    Publication date: July 4, 2013
    Inventors: Suzuka Amemori, Masahide Yamada, Yoshihiro Moriya, Taichi Nemoto, Yukiko Nakajima, Yoshitaka Yamauchi, Daiki Yamashita, Keiji Makabe, Akiyoshi Sabu
  • Publication number: 20130149642
    Abstract: To provide a toner, which contains a first binder resin, and a second binder resin, wherein the first binder resin is a block polymer containing at least a polyester skeleton A having, in a repeating structure thereof, a constitutional unit formed by dehydration condensation of hydroxycarboxylic acid, and a skeleton B that does not have, in a repeating structure thereof, a constitutional unit formed by dehydration condensation of hydroxycarboxylic acid, and the first binder resin has glass transition temperature Tg1 and Tg 2 as measured by differential scanning calorimetry at a heating rate of 5° C./min, wherein the Tg1 is ?20° C. to 20° C., and the Tg2 is 35° C. to 65° C., and wherein the second binder resin is a crystalline resin.
    Type: Application
    Filed: November 20, 2012
    Publication date: June 13, 2013
    Inventors: Akiyoshi SABU, Yoshihiro MORIYA, Taichi NEMOTO, Yoshitaka YAMAUCHI, Yukiko NAKAJIMA, Keiji MAKABE, Suzuka AMEMORI, Daiki YAMASHITA, Masahide YAMADA
  • Publication number: 20130065172
    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: Application
    Filed: September 11, 2012
    Publication date: March 14, 2013
    Inventors: Yoshihiro MORIYA, Masahide YAMADA, Taichi NEMOTO, Yukiko NAKAJIMA, Yoshitaka YAMAUCHI, Daiki YAMASHITA, Keiji MAKABE, Akiyoshi SABU, Suzuka AMEMORI
  • Patent number: 8383307
    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: Grant
    Filed: October 8, 2009
    Date of Patent: February 26, 2013
    Assignee: Ricoh Company, Limited
    Inventors: Ryota Inoue, Akihiro Kotsugai, Toyoshi Sawada, Akiyoshi Sabu
  • Publication number: 20130045442
    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: Application
    Filed: August 2, 2012
    Publication date: February 21, 2013
    Inventors: Yoshihiro MORIYA, Shinya Nakayama, Atsushi Yamamoto, Hideyuki Santo, Akiyoshi Sabu, Yukiko Nakajima, Daiki Yamashita
  • Patent number: 8329370
    Abstract: An image forming apparatus including: a latent electrostatic image bearing member, a charging unit, an exposing unit, a developing unit, a transfer unit, and a fixing unit, wherein the toner contains at least a binder resin and a colorant, the binder resin contains a polyester resin obtained by polycondensation of an alcohol component with a carboxylic acid component containing a rosin compound, the amount of the rosin compound contained in the carboxylic acid component is 5% by mass or more based on the total mass of the alcohol component and carboxylic acid component, and the amount of an abietic acid contained in the toner is 1% by mass or less.
    Type: Grant
    Filed: October 17, 2008
    Date of Patent: December 11, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Shinya Nakayama, Akihiro Kotsugai, Akiyoshi Sabu