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).
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TONER, DEVELOPING AGENT, TONER HOUSING UNIT, IMAGE FORMING APPARATUS, AND A METHOD OF FORMING IMAGES
Publication number: 20220326632Abstract: [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: ApplicationFiled: March 31, 2022Publication date: October 13, 2022Applicant: Ricoh Company, Ltd.Inventors: Keiji MAKABE, Akira Tanaka, Hidekazu Kakinuma, Tsukiko Takahashi -
Patent number: 11079700Abstract: 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: GrantFiled: March 6, 2020Date of Patent: August 3, 2021Assignee: Ricoh Company, Ltd.Inventors: Keiji Makabe, Tsuneyasu Nagatomo, Kohsuke Satoh, Daichi Hisakuni, Kousuke Suzuki, Shintaro Akiyama
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Patent number: 11061345Abstract: A toner including toner particles, each toner particle including a toner base particle, and inorganic particles, wherein the inorganic particles include particles of a fluorine-containing aluminium compound, and a liberation ratio of the inorganic particles is 10% or greater but 60% or less.Type: GrantFiled: February 24, 2020Date of Patent: July 13, 2021Assignee: Ricoh Company, Ltd.Inventors: Kohsuke Satoh, Tsuneyasu Nagatomo, Keiji Makabe, Daichi Hisakuni
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Patent number: 11054757Abstract: A toner including toner base particles each including a binder resin and a colorant, and external additive, wherein the toner satisfies conditions (a), (b), and (c) below: (a) storage elastic modulus G?(50) of the toner at 50° C. and storage elastic modulus G?(90) of the toner at 90° C. satisfy Formula (1); G?(50)/G?(90)?6.0×102??Formula (1) (b) a BET specific surface area Bt(m2/g) of the toner and a coverage Ct (%) of the toner base particles covered with the external additive satisfy Formula (2); and Bt?0.03×Ct?1.60??Formula (2) (c) the external additive includes at least cohered particles, the cohered particles are non-spherical secondary particles each formed through cohesion of primary particles, and a number average secondary particle diameter of the cohered particles is 130 nm or greater.Type: GrantFiled: September 26, 2019Date of Patent: July 6, 2021Assignee: Ricoh Company, Ltd.Inventors: Yohichi Kitagawa, Keiji Makabe, Yuka Mizoguchi, Tsuneyasu Nagatomo, Shinya Nakayama
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Publication number: 20200301308Abstract: 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: ApplicationFiled: March 6, 2020Publication date: September 24, 2020Inventors: Keiji MAKABE, Tsuneyasu NAGATOMO, Kohsuke SATOH, Daichi HISAKUNI, Kousuke SUZUKI, Shintaro AKIYAMA
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Publication number: 20200272066Abstract: A toner including toner particles, each toner particle including a toner base particle, and inorganic particles, wherein the inorganic particles include particles of a fluorine-containing aluminium compound, and a liberation ratio of the inorganic particles is 10% or greater but 60% or less.Type: ApplicationFiled: February 24, 2020Publication date: August 27, 2020Inventors: Kohsuke Satoh, Tsuneyasu Nagatomo, Keiji Makabe, Daichi Hisakuni
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Publication number: 20200103775Abstract: A toner including toner base particles each including a binder resin and a colorant, and external additive, wherein the toner satisfies conditions (a), (b), and (c) below: (a) storage elastic modulus G?(50) of the toner at 50° C. and storage elastic modulus G?(90) of the toner at 90° C. satisfy Formula (1); G?(50)/G?(90)?6.0×102??Formula (1) (b) a BET specific surface area Bt(m2/g) of the toner and a coverage Ct (%) of the toner base particles covered with the external additive satisfy Formula (2); and Bt?0.03×Ct?1.60??Formula (2) (c) the external additive includes at least cohered particles, the cohered particles are non-spherical secondary particles each formed through cohesion of primary particles, and a number average secondary particle diameter of the cohered particles is 130 nm or greater.Type: ApplicationFiled: September 26, 2019Publication date: April 2, 2020Inventors: Yohichi Kitagawa, Keiji Makabe, Yuka Mizoguchi, Tsuneyasu Nagatomo, Shinya Nakayama
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Patent number: 10295919Abstract: 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: GrantFiled: December 19, 2017Date of Patent: May 21, 2019Assignee: Ricoh Company, Ltd.Inventors: Keiji Makabe, Tsuneyasu Nagatomo, Kohsuke Satoh, Kenji Yoneda
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Publication number: 20180181014Abstract: 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: ApplicationFiled: December 19, 2017Publication date: June 28, 2018Inventors: Keiji MAKABE, Tsuneyasu NAGATOMO, Kohsuke SATOH, Kenji YONEDA
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Patent number: 9851649Abstract: 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: GrantFiled: November 27, 2013Date of Patent: December 26, 2017Assignee: Ricoh Company, Ltd.Inventors: Keiji Makabe, Tsuyoshi Sugimoto, Akinori Saito, Suzuka Amemori, Toyoshi Sawada, Hiroshi Yamashita, Shinya Nakayama, Atsushi Yamamoto, Daisuke Asahina, Satoyuki Sekiguchi
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Patent number: 9804516Abstract: 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: GrantFiled: April 21, 2016Date of Patent: October 31, 2017Assignee: Ricoh Company, Ltd.Inventors: Keiji Makabe, Tsuneyasu Nagatomo, Kohsuke Satoh, Junichi Watanabe, Kenji Yoneda, Daichi Hisakuni
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Patent number: 9791794Abstract: A toner includes a base particle comprising a crystalline polyester resin; and an external additive which is a group of silica particles having a number-average particle diameter of from 0.01 ?m to 0.11 ?m on the surface of the toner. A number ratio of the silica particles having a circularity not less than 0.8 is 20% or more in the total number of the silica particles.Type: GrantFiled: February 24, 2016Date of Patent: October 17, 2017Assignee: Ricoh Company, Ltd.Inventors: Junichi Watanabe, Kenji Yoneda, Kohsuke Satoh, Tsuneyasu Nagatomo, Keiji Makabe, Daichi Hisakuni
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Patent number: 9594322Abstract: 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: GrantFiled: August 28, 2014Date of Patent: March 14, 2017Assignee: Ricoh Company, Ltd.Inventors: Suzuka Amemori, Tsuyoshi Sugimoto, Akinori Saito, Toyoshi Sawada, Keiji Makabe
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Publication number: 20160334722Abstract: 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: ApplicationFiled: April 21, 2016Publication date: November 17, 2016Inventors: Keiji MAKABE, Tsuneyasu Nagatomo, Kohsuke Satoh, Junichi Watanabe, Kenji Yoneda, Daichi Hisakuni
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Publication number: 20160266507Abstract: A toner includes a base particle comprising a crystalline polyester resin; and an external additive which is a group of silica particles having a number-average particle diameter of from 0.01 ?m to 0.11 ?m on the surface of the toner. A number ratio of the silica particles having a circularity not less than 0.8 is 20% or more in the total number of the silica particles.Type: ApplicationFiled: February 24, 2016Publication date: September 15, 2016Inventors: Junichi WATANABE, Kenji Yoneda, Kohsuke Satoh, Tsuneyasu Nagatomo, Keiji Makabe, Daichi Hisakuni
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Publication number: 20160091812Abstract: 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: ApplicationFiled: November 27, 2013Publication date: March 31, 2016Inventors: Keiji MAKABE, Tsuyoshi SUGIMOTO, Akinori SAITO, Suzuka AMEMORI, Toyoshi SAWADA, Hiroshi YAMASHITA, Shinya NAKAYAMA, Atsushi YAMAMOTO, Daisuke ASAHINA, Satoyuki SEKIGUCHI
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Patent number: 9176406Abstract: Toner contains a binder resin containing a crystalline resin having a urethane and/or urea bonding; and a colorant, wherein in a diffraction spectrum of the toner as measured by an X-ray diffraction instrument, a ratio {C/(C+A)} of an integral intensity C of the spectrum derived from the crystalline structure to an integral intensity A of the spectrum derived from the non-crystalline structure is 0.12 or greater, wherein the toner satisfies the following relation 1: T1?T2?30° C. (Relation 1), where T1 represents the maximum endothermic peak in the first temperature rising from 0° C. to 100° C. at the temperature rising rate of 10° C./min and T2 represents the maximum exothermic peak in the first temperature falling from 100° C. to 0° C. at the temperature falling rate of 10° C./min as T1 and T2 are measured by diffraction scanning calorimetry (DSC).Type: GrantFiled: August 5, 2013Date of Patent: November 3, 2015Assignee: Ricoh Company, Ltd.Inventors: Satoyuki Sekiguchi, Hiroshi Yamashita, Minoru Masuda, Susumu Chiba, Tatsuya Morita, Atsushi Yamamoto, Shinya Nakayama, Masahide Yamada, Kohsuke Nagata, Keiji Makabe, Toyoshi Sawada
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Patent number: 9141013Abstract: An electrophotographic toner including: a binder resin, wherein the binder resin has one glass transition temperature Tg and the glass transition temperature Tg of the binder resin is within 25° C. to 65° C. as measured in second heating with a differential scanning calorimeter at a heating rate of 5° C./min, and wherein a phase image of the binder resin obtained with an atomic force microscope (AFM) of tapping mode contains first phase difference regions and a second phase difference region such that the first phase difference regions are dispersed in the second phase difference region, where the first phase difference regions correspond to greater phase difference regions and the second phase difference region corresponds to a smaller phase difference region when an intermediate value between a maximum value and a minimum value of the phase differences is used as a threshold.Type: GrantFiled: September 12, 2012Date of Patent: September 22, 2015Assignee: Ricoh Company, Ltd.Inventors: Yoshihiro Moriya, Masahide Yamada, Taichi Nemoto, Yukiko Nakajima, Yoshitaka Yamauchi, Keiji Makabe, Daiki Yamashita, Suzuka Amemori, Akiyoshi Sabu
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Patent number: 9128397Abstract: 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: GrantFiled: May 15, 2012Date of Patent: September 8, 2015Assignee: Ricoh Company, Ltd.Inventors: Yukiko Nakajima, Masahide Yamada, Taichi Nemoto, Yoshihiro Moriya, Yoshitaka Yamauchi, Keiji Makabe, Daiki Yamashita, Akiyoshi Sabu
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Patent number: 9127118Abstract: A resin for toner contains a polyhydroxycarboxylic acid skeleton and a rigid skeleton.Type: GrantFiled: March 7, 2012Date of Patent: September 8, 2015Assignee: 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