Patents by Inventor Keiji MAKABE

Keiji MAKABE 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).

  • Publication number: 20240310746
    Abstract: Toner may comprise toner particles that comprise a binder resin; the toner particles have a volume average particle diameter from 4.0 ?m to 6.0 ?m, and the toner has a number content of coarse particle of 20 ?m or more from 10 to 250 in 10 mg of the toner.
    Type: Application
    Filed: March 15, 2024
    Publication date: September 19, 2024
    Inventors: Daisuke INOUE, Keiji MAKABE, Tsukiko TAKAHASHI, Taishi YAMASHITA, Shuto SUNAGA
  • Publication number: 20240241458
    Abstract: A toner contains a mother toner particle containing a resin, a colorant, and a wax and an inorganic external additive on the surface of the mother toner particle, wherein the following relationships are satisfied: 20 < A ? 4 ? 0 Relationship ? 1 0 ? B - A ? 10 , Relationship ? 2 2.3 < C < 5. Relationship ? 3 where A (percent by mass) represents the liberation ratio of the inorganic external additive separated by shaking the toner with ultrasonic wave at a power of 20 W and a frequency of 20 kHz for one minute, B (percent by mass) represents the liberation ratio of the inorganic external additive separated by shaking the toner with ultrasonic wave at a power of 60 W and a frequency of 20 kHz for one minute, and C (percent by mass) represents the proportion of the inorganic external additive to the toner.
    Type: Application
    Filed: January 17, 2024
    Publication date: July 18, 2024
    Inventors: Tsukiko TAKAHASHI, Daisuke INOUE, Keiji MAKABE, Taishi YAMASHITA, Shuto SUNAGA
  • Publication number: 20220326632
    Abstract: [Object] An object of the invention is to provide a toner that can both achieve a higher level of low temperature fixability and suppression of the toner scattering. [Means of Achieving the Object] The disclosure is to provide a toner, including base-particles, and an external-additive, wherein a glass-transition temperature obtained from a DSC-curve at a second-warming of a THF-insoluble component is ?50° C. or higher and 10° C. or lower, wherein an average circularity of the toner is 0.975 or more and 0.985 or lower, wherein the toner satisfies the following formula: 1.5?Bt?0.025?Ct?3.0, wherein the Bt [m2/g] is a BET-specific-surface area of the toner-particles, and the Ct [%] is a coverage by the external-additive, and, at least a portion of a surface of the external-additive is coated with either an oxide of a metallic element, a hydroxide of the metallic element, or both.
    Type: Application
    Filed: March 31, 2022
    Publication date: October 13, 2022
    Applicant: Ricoh Company, Ltd.
    Inventors: Keiji MAKABE, Akira Tanaka, Hidekazu Kakinuma, Tsukiko Takahashi
  • Publication number: 20200301308
    Abstract: An image forming apparatus is provided that includes: an image bearer; a charger; an irradiator; a developing device containing a toner; and a transfer device. The image bearer has a Martens hardness of from 185 to 250 N/m2. The toner satisfies a relation 0.13?X/Dn?0.16, where X [?m] represents an average value of an amount of deformation of the toner by micro-indentation at when a load reaches 3.00×10?4 N at a loading rate of 3.0×10?5 N/sec under an environment of 32 degrees C. and 40% RH, and Dn [?m] represents a number average particle diameter of the toner. The toner contains an external additive comprising silica particles and particles composed mainly of strontium titanate. The particles composed mainly of strontium titanate further contain a third element M selected from the group consisting of La, Mg, Ca, Sn, and Si.
    Type: Application
    Filed: March 6, 2020
    Publication date: September 24, 2020
    Inventors: Keiji MAKABE, Tsuneyasu NAGATOMO, Kohsuke SATOH, Daichi HISAKUNI, Kousuke SUZUKI, Shintaro AKIYAMA
  • Publication number: 20180181014
    Abstract: A toner is provided. The toner includes toner particles each including a mother particle and external additive particles covering the mother particle. In a SEM image of the toner, toner particles having a ratio Sd/St of from 5% to 50% are present at a frequency of 15% or more, where Sd representing an area of a largest recessed portion D of each toner particle and St representing whole area of the toner particle, Sd and St determined from the SEM image magnified and binarized to discriminate recessed portions and projected portions of the toner particle from each other. An external additive coverage rate Ca at the largest recessed portion D is from 30% to 100%.
    Type: Application
    Filed: December 19, 2017
    Publication date: June 28, 2018
    Inventors: Keiji MAKABE, Tsuneyasu NAGATOMO, Kohsuke SATOH, Kenji YONEDA
  • Publication number: 20160334722
    Abstract: A toner includes a base particle; and an external additive covering the base particle. The toner includes a tetrahydrofuran (THF)-insoluble component having a glass transition temperature determined from a DSC curve when heated for the second time of from ?50° C. to 10° C. and an average circularity not greater than 0.98, and satisfies the following relation: Bt?0.025×Ct?1.80 wherein Bt represents a BET specific surface area [m2/g]; and Ct represents a coverage [%] of the external additive covering the base particle.
    Type: Application
    Filed: April 21, 2016
    Publication date: November 17, 2016
    Inventors: Keiji MAKABE, Tsuneyasu Nagatomo, Kohsuke Satoh, Junichi Watanabe, Kenji Yoneda, Daichi Hisakuni
  • Publication number: 20160091812
    Abstract: A toner includes a binder resin including a copolymer resin containing structural units derived from crystalline and non-crystalline resins, respectively. Spin-spin relaxation time (t50) of the toner at 50° C. measured by pulse NMR is ?0.05 msec., spin-spin relaxation time (t130) at 130° C. when warmed from 50° C. to 130° C. is >15 msec., and spin-spin relaxation time (t?70) at 70° C. when cooled from 130° C. to 70° C. is ?1.00 msec. A binarized image obtained by binarizing a phase image of the toner observed by a tapping mode AFM based on intermediate value between maximum and minimum phase difference values in the phase image includes first phase difference images constituted by large phase-difference portions and a second phase difference image constituted by a small phase-difference portion. The first phase difference images are dispersed in the second phase difference image. The dispersion diameter of the first phase difference images is 150 nm or less.
    Type: Application
    Filed: November 27, 2013
    Publication date: March 31, 2016
    Inventors: Keiji MAKABE, Tsuyoshi SUGIMOTO, Akinori SAITO, Suzuka AMEMORI, Toyoshi SAWADA, Hiroshi YAMASHITA, Shinya NAKAYAMA, Atsushi YAMAMOTO, Daisuke ASAHINA, Satoyuki SEKIGUCHI
  • Publication number: 20150212442
    Abstract: A toner is provided. The toner includes mother toner particles. Each mother toner particle includes a binder resin and inorganic-layer-containing resin particles. Each inorganic-layer-containing resin particle includes a resin particle and an inorganic layer on the surface of the resin particle.
    Type: Application
    Filed: January 28, 2015
    Publication date: July 30, 2015
    Inventors: Masayuki ISHII, Toyoshi SAWADA, Keiji MAKABE
  • Publication number: 20150072287
    Abstract: A toner is provided. The toner includes a crosslinked polyester resin, and a block copolymer. The crosslinked polyester resin includes a diol component, which includes an aliphatic diol component having 3 to 10 carbon atoms in an amount of 50% by mole, and a crosslinked component, which is at least one of a crosslinked component of an aliphatic alcohol having three or more valences and a crosslinked component of an aliphatic acid having three or more valences, and the block copolymer includes a crystalline segment (a) and a non-crystalline segment (b). The toner has a first glass transition temperature (Tg1st) of from 20° C. to 50° C., which is determined by subjecting the toner to differential scanning calorimetry (DSC) and measuring a glass transition temperature in a first temperature rising process in the differential scanning calorimetry (DSC).
    Type: Application
    Filed: August 28, 2014
    Publication date: March 12, 2015
    Inventors: Suzuka AMEMORI, Tsuyoshi SUGIMOTO, Akinori SAITO, Toyoshi SAWADA, Keiji MAKABE
  • Publication number: 20140080051
    Abstract: To provide a toner (X), which contains toner particles, each toner particle contains: a core phase (Q) containing a crystalline resin (A); and a shell phase (S) provided on a surface of the core phase (Q), where the shell phase (S) contains a crystalline polyurethane resin (B), wherein maximum peak temperature (Ta) of heat of melting of the crystalline resin (A) is 40° C. to 70° C., and maximum peak temperature (Tu) of heat of melting of the crystalline polyurethane resin (B) is 50° C. to 90° C.
    Type: Application
    Filed: September 17, 2013
    Publication date: March 20, 2014
    Inventors: Toyoshi SAWADA, Masahide YAMADA, Atsushi YAMAMOTO, Tatsuya MORITA, Satoyuki SEKIGUCHI, Keiji MAKABE, Kousuke NAGATA
  • 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: 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
  • Publication number: 20120295188
    Abstract: A resin for use in toner is provided. The resin comprises an oligomer segment and a soft segment. The oligomer segment comprises a polyhydroxycarboxylic skeleton and an aromatic diol skeleton.
    Type: Application
    Filed: May 15, 2012
    Publication date: November 22, 2012
    Inventors: Yukiko NAKAJIMA, Masahide YAMADA, Taichi NEMOTO, Yoshihiro MORIYA, Yoshitaka YAMAUCHI, Keiji MAKABE, Daiki YAMASHITA, Akiyoshi SABU
  • Publication number: 20120231383
    Abstract: A resin for toner containing a polyhydroxy carbonate skeleton and a rigid skeleton.
    Type: Application
    Filed: March 7, 2012
    Publication date: September 13, 2012
    Applicant: RICOH COMPANY, LTD.
    Inventors: Hideyuki SANTO, Shinya NAKAYAMA, Atsushi YAMAMOTO, Yoshihiro MORIYA, Akiyoshi SABU, Daisuke ASAHINA, Yoshitaka YAMAUCHI, Taichi NEMOTO, Yukiko NAKAJIMA, Daiki YAMASHITA, Masahide YAMADA, Keiji MAKABE
  • Publication number: 20110305987
    Abstract: A method for producing toner particles by ejecting a liquid from at least one ejection hole to form the liquid into liquid droplets, and solidifying the liquid droplets to produce toner particles. The ejecting is accomplished by applying a vibration to the liquid in a liquid column resonance-generating liquid chamber in which an ejection hole is formed to form a standing wave through liquid column resonance, and ejecting the liquid from the ejection hole which is formed in a region corresponding to an antinode of the standing wave to thereby form the liquid into the liquid droplets. Toner produced by the method.
    Type: Application
    Filed: May 20, 2011
    Publication date: December 15, 2011
    Inventors: Watanabe YOHICHIROH, Yoshihiro NORIKANE, Yasutada SHITARA, Keiji MAKABE