Patents by Inventor Yoshimichi Ishikawa

Yoshimichi Ishikawa 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: 20140147779
    Abstract: A toner is provided. The toner includes a crystalline resin and a non-crystalline resin, and has a thermal property such that when the toner is heated after being firstly heated to 60° C. followed by cooling in differential scanning calorimetry (DSC), the toner has a clear peak specific to melting of the crystalline resin at a temperature T1, and when the toner is heated after being firstly heated to 80° C. followed by cooling in the differential scanning calorimetry (DSC), the toner does not have a clear peak specific to melting of the crystalline resin at a temperature not higher than the temperature T1.
    Type: Application
    Filed: October 1, 2013
    Publication date: May 29, 2014
    Inventors: Kazuoki FUWA, Takuya KADOTA, Yoshihiro MIKURIYA, Tsuyoshi NOZAKI, Yoshimichi ISHIKAWA, Yuta TAKEUCHI, Tomohiro FUKAO, Tomoharu MIKI, Takayuki NAKAMURA
  • Publication number: 20140147780
    Abstract: A toner is prepared by wet granulation methods, including a monoester wax having carbon atoms of from 36 to 46 on average as a release agent. The toner has a DSC endothermic energy amount (?H1) originating from the wax of from 10 to 12 mJ/mg and a DSC endothermic energy amount (?H2) originating from the wax of from 0.6 to 0.9 times as much as ?H1 after a part of the wax is separated by hexane extraction from the toner. The hexane extraction includes mixing 1 g of the toner in 7 ml of n-hexane to prepare a mixture; stirring the mixture at 120 rpm for 1 min by a pot mill to prepare a dispersion; and subjecting the dispersion to suction filtration.
    Type: Application
    Filed: October 23, 2013
    Publication date: May 29, 2014
    Inventors: Tsuyoshi NOZAKI, Takuya Kadota, Yoshihiro Mikuriya, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki
  • Patent number: 8691484
    Abstract: Disclosed is a non-magnetic toner for use in developing electrostatic toner image, wherein the toner is produced by a toner production method that includes: dispersing in an aqueous medium an organic dispersion liquid that comprises in an organic solvent a pigment, a binder resin and/or a binder resin precursor, and a releasing agent; removing the organic solvent to prepare a dispersion slurry in which toner particles are dispersed in the aqueous medium; heating the dispersion slurry to a temperature equal to or higher than the melting point of the releasing agent; and washing the toner particles.
    Type: Grant
    Filed: March 12, 2008
    Date of Patent: April 8, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuyoshi Nozaki, Chiyoshi Nozaki, Atsushi Yamamoto, Mitsuyo Matsumoto, Takuya Kadota, Katsunori Kurose, Yoshimichi Ishikawa
  • Publication number: 20140050504
    Abstract: An electrostatic image developing toner including: toner base particles each including a binder resin and a colorant; and an external additive, wherein the toner base particles each have protrusions on a surface thereof, an average of lengths of long sides of the protrusions is 0.1 ?m or more but less than 0.5 ?m, a standard deviation of the lengths of the long sides of the protrusions is 0.2 or less, a coverage rate of the protrusions on the surface of each toner base particle is 10% to 90%, and the external additive includes an external additive (A) which is fine inorganic particles each containing silicone oil.
    Type: Application
    Filed: April 25, 2012
    Publication date: February 20, 2014
    Inventors: Tomohiro Fukao, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomoharu Miki
  • Patent number: 8647803
    Abstract: A method for producing colored resin particles including: dissolving or dispersing at least binder resin and colorant in organic solvent to prepare oil phase; dissolving resin A and basic compound in aqueous medium to prepare aqueous phase, the resin A having solubility <2.0 g/100 g water having temperature 25° C. and pH 3.0 and solubility ?2.0 g/100 g water having temperature 25° C. and pH 10.0; dispersing the oil phase in the aqueous phase to prepare core particle dispersion liquid; dispersing resin particles in aqueous medium to prepare resin particle dispersion liquid, and adding the resin particle dispersion liquid to the core particle dispersion liquid so that the resin particles are attached onto the core particles, to prepare dispersion liquid containing particles each having the core particle and the resin particles attached thereonto; removing the organic solvent from the dispersion liquid; washing the particles; and drying the particles.
    Type: Grant
    Filed: February 1, 2012
    Date of Patent: February 11, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Atsushi Yamamoto, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki
  • Publication number: 20140038095
    Abstract: A toner including: toner particles each including a toner base particle and an external additive attached thereon, where the toner base particle includes a binder resin and a colorant, wherein the toner base particles each have protrusions on a surface thereof, an average of lengths of long sides of the protrusions is 0.10 ?m or more but less than 0.50 ?m, a standard deviation of the lengths of the long sides of the protrusions is 0.2 or less, a coverage rate of the protrusions on the surface of the toner base particle is 10% to 90%, and the external additive includes fine inorganic particles whose surfaces have been treated with an amino group-containing silane coupling agent.
    Type: Application
    Filed: April 25, 2012
    Publication date: February 6, 2014
    Inventors: Yoshimichi Ishikawa, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki
  • Patent number: 8642238
    Abstract: A toner including: a core particle; and fine resin particles, the core particle containing at least a binder resin, a releasing agent and a colorant, wherein the toner is in shape of particles, and each toner particle has a sea-island structure having the core particle and island portions, which are convex portions formed from the fine resin particles on surface of the core particle, wherein the binder resin contains first and second resins, and the fine resin particles are made of third resin, wherein the first resin is crystalline resin, and the second and third resins are non-crystalline resin, wherein the second resin has glass transition temperature (Tg2) and the crystalline resin has melting point (Tc1) where Tg2 is higher than Tc1, and wherein the third resin has glass transition temperature (Tg3) and the toner has glass transition temperature (Tgt) wherein Tg3 is higher than Tgt.
    Type: Grant
    Filed: July 25, 2012
    Date of Patent: February 4, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Tsuyoshi Nozaki, Tomoharu Miki, Tomohiro Fukao, Kazuoki Fuwa, Yoshimichi Ishikawa, Yoshihiro Mikuriya, Takuya Kadota
  • Patent number: 8623581
    Abstract: An electrostatic image developing toner including: toner particles each containing binder resin and colorant; and an external additive supported on the toner particles, wherein the toner particles each have protrusions on surface thereof, average of lengths of long sides of the protrusions is 0.10 ?m or more but less than 0.50 ?m, standard deviation of the lengths of the long sides of the protrusions is 0.20 or less, coverage rate of the protrusions on the surface of each toner particle is 30% to 90%, the external additive includes at least two different particles including external additive (A) and one or more external additives (B), external additive (A) has longest average primary particle diameter among the external additives and charged to have the opposite polarity to the toner particles, and at least one of the external additives (B) is charged to have the same polarity as the toner particles.
    Type: Grant
    Filed: March 16, 2012
    Date of Patent: January 7, 2014
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomohiro Fukao, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomoharu Miki
  • Publication number: 20130344427
    Abstract: To provide a toner, which contains a binder resin, a colorant, and a silicone oil-treated external additive, wherein the silicone oil-treated external additive contains free silicone oil, and a total amount of the free silicone oil is 0.2% by mass to 0.5% by mass relative to the toner, and wherein the toner has the average circularity of 0.96 to 1.
    Type: Application
    Filed: March 9, 2012
    Publication date: December 26, 2013
    Inventors: Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki, Masayuki Hagi, Hidekazu Shono, Manabu Hamada, Tetsushi Sakuma
  • Patent number: 8614040
    Abstract: An electrostatic image developing toner including: toner particles; wherein the toner particles each contain: a core particle including a first resin and a colorant; and fine resin particles each formed of a second resin and existing in a surface of the core particle, wherein part of each fine resin particle is embedded in the core particle to form an embedded region, and the remaining part of the fine resin particle is exposed on the surface of the core particle to form an exposed region, and wherein each toner particle satisfies an expression of R1>R1? where, in a cross-section of the toner particle, R1? denotes an average diameter of openings of the first resin in which the second resin is embedded and R1 denotes an average diameter of the exposed regions.
    Type: Grant
    Filed: March 12, 2012
    Date of Patent: December 24, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomohiro Fukao, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomoharu Miki
  • Patent number: 8518625
    Abstract: An electrostatic image developing toner including toner core particles each containing at least a first resin and a colorant, and fine resin particles formed of a second resin, wherein part of each of the fine resin particles is embedded in each of the toner core particles, and the remaining part of the fine resin particle is exposed on a surface of the toner core particle to form a protrusion, and wherein when a rate of the part of the fine resin particle to the fine resin particle is indicated by an embedment rate, an average of the embedment rates in the fine resin particles is 40% to 80%.
    Type: Grant
    Filed: May 23, 2011
    Date of Patent: August 27, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Tomohiro Fukao, Takuya Kadota, Chieko Yamazaki, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Atsushi Yamamoto, Kazuoki Fuwa, Tomoharu Miki
  • Patent number: 8440380
    Abstract: A toner containing core particles each containing at least a resin A having a polyester skeleton and a colorant; and vinyl resin fine particles each of which encapsulates a resin B having at least a polyester skeleton and an endothermic peak measured by differential scanning calorimeter (DSC) at 40° C. to 110° C., wherein the vinyl resin fine particles are attached onto each of the core particles.
    Type: Grant
    Filed: December 6, 2010
    Date of Patent: May 14, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Atsushi Yamamoto, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki, Masayuki Hagi
  • Patent number: 8435709
    Abstract: A toner for developing a latent electrostatic image produced by suspension polymerizing a polymerizable monomer composition in an aqueous dispersion medium, wherein the polymerizable monomer composition contains a polymerizable monomer, a colorant, and a layered inorganic mineral in which at least a part of an interlayer ion is replaced with an organic ion, and a process cartridge and an image forming method using the toner.
    Type: Grant
    Filed: March 17, 2008
    Date of Patent: May 7, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Atsushi Yamamoto, Chiyoshi Nozaki, Tsuyoshi Nozaki, Takuya Kadota, Hiroyuki Murakami, Mitsuyo Matsumoto, Katsunori Kurose, Yoshimichi Ishikawa
  • Patent number: 8431314
    Abstract: The present invention provides a method for producing a colored resin particle, the method including: preparing an oil phase in which at least a resin and a colorant are dissolved or dispersed in an organic solvent; preparing an aqueous phase containing at least a surfactant in an aqueous medium; dispersing the oil phase in the aqueous phase to prepare a colored particle dispersion liquid so as to form core particles; causing resin fine particles to adhere to surfaces of the core particles by adding at least the resin fine particles to the colored particle dispersion liquid, in which the core particles have been formed; removing the solvent from the colored particle dispersion liquid to obtain colored resin particles, washing the colored resin particles, and drying the colored resin particles, wherein an inorganic base is dissolved in the colored particle dispersion liquid.
    Type: Grant
    Filed: August 27, 2010
    Date of Patent: April 30, 2013
    Assignee: Ricoh Company, Ltd.
    Inventors: Yoshihiro Mikuriya, Tomoharu Miki, Tomohiro Fukao, Kazuoki Fuwa, Takuya Kadota, Yoshimichi Ishikawa, Atsushi Yamamoto, Tsuyoshi Nozaki
  • Publication number: 20130029260
    Abstract: A toner including: a core particle; and fine resin particles, the core particle containing at least a binder resin, a releasing agent and a colorant, wherein the toner is in shape of particles, and each toner particle has a sea-island structure having the core particle and island portions, which are convex portions formed from the fine resin particles on surface of the core particle, wherein the binder resin contains first and second resins, and the fine resin particles are made of third resin, wherein the first resin is crystalline resin, and the second and third resins are non-crystalline resin, wherein the second resin has glass transition temperature (Tg2) and the crystalline resin has melting point (Tc1) where Tg2 is higher than Tc1, and wherein the third resin has glass transition temperature (Tg3) and the toner has glass transition temperature (Tgt) wherein Tg3 is higher than Tgt.
    Type: Application
    Filed: July 25, 2012
    Publication date: January 31, 2013
    Inventors: Tsuyoshi NOZAKI, Tomoharu Miki, Tomohiro Fukao, Kazuoki Fuwa, Yoshimichi Ishikawa, Yoshihiro Mikuriya, Takuya Kadota
  • Patent number: 8354164
    Abstract: A semiconductive member including an alkali metal salt having the formula (M)n.X in a surface layer thereof. M represents Na+, K+, or Li+; X represents Cl?, Br?, I?, F?, CH3COO?, CF3COO?, CH(COOH)CHCOO?, (CHCOO?)2, CH2(COOH)CH2COO?, (CH2COO?)2, (HOOC)Ar(COO?), Ar(COO?)2, (HOOC)2Ar(COO?), (HOOC)Ar(COO?)2, Ar(COO?)3, (HOOC)3Ar(COO?), (HOOC)2Ar(COO?)2, (HOOC)Ar(COO?)3, Ar(COO?)4, Ar—SO3?, Ar(SO3?)2, an oligomer or a polymer having an acrylic acid anion unit, or an oligomer or a polymer having an methacrylic acid anion unit; Ar represents a benzene ring, a naphthalene ring, or a biphenyl ring; and n is a numeral equivalent to the anionic valence of X.
    Type: Grant
    Filed: November 20, 2009
    Date of Patent: January 15, 2013
    Assignee: Ricoh Company, Limited
    Inventors: Chiyoshi Nozaki, Tetsumaru Fujita, Shintaro Yamada, Yuji Nagatomo, Shin Murayama, Manabu Hamada, Yoshimichi Ishikawa
  • Patent number: 8309290
    Abstract: A toner including toner particles comprising a binder resin, a coloring agent and a wax. The toner particles are prepared by agglomerating and/or fusing at least two kinds of resin particulates and particles of the coloring agent dispersed in an aqueous medium. A first resin particulate among the at least two kinds of resin particulates contains a resin having a polyester skeleton and the wax. At least 50% by weight of the binder resin is polyester resins.
    Type: Grant
    Filed: September 14, 2007
    Date of Patent: November 13, 2012
    Assignee: Ricoh Company, Ltd.
    Inventors: Atsushi Yamamoto, Chiyoshi Nozaki, Tsuyoshi Nozaki, Mitsuyo Matsumoto, Takuya Kadota, Hiroyuki Murakami, Katsunori Kurose, Yoshimichi Ishikawa
  • Publication number: 20120264048
    Abstract: Provided is a toner including: toner particles, each toner particle containing a toner base particle, wherein the toner contains a binder resin; and a colorant, wherein the toner base particle has protrusions at a surface thereof, wherein an average of lengths of long sides of the protrusions is 0.1 ?m or more but less than 0.5 ?m, a standard deviation of the lengths of the long sides of the protrusions is 0.20 or less, and a coverage rate of the protrusions is 30% to 90%, wherein a resin forming the protrusions is prepared through polymerization of a monomer mixture containing at least a monomer having a sulfonic acid group, and wherein the monomer mixture contains styrene in an amount of 90% by mass or more and the monomer having a sulfonic acid group in an amount of 0.1% by mass to 5% by mass.
    Type: Application
    Filed: April 10, 2012
    Publication date: October 18, 2012
    Inventors: Yoshimichi ISHIKAWA, Takuya KADOTA, Yoshihiro MIKURIYA, Tsuyoshi NOZAKI, Kazuoki FUWA, Tomohiro FUKAO, Tomoharu MIKI, Atsushi YAMAMOTO
  • Publication number: 20120251938
    Abstract: A method for producing colored resin particles including: dissolving or dispersing at least binder resin and colorant in organic solvent to prepare oil phase; dissolving resin A and basic compound in aqueous medium to prepare aqueous phase, the resin A having solubility <2.0 g/100 g water having temperature 25° C. and pH 3.0 and solubility ?2.0 g/100 g water having temperature 25° C. and pH 10.0; dispersing the oil phase in the aqueous phase to prepare core particle dispersion liquid; dispersing resin particles in aqueous medium to prepare resin particle dispersion liquid, and adding the resin particle dispersion liquid to the core particle dispersion liquid so that the resin particles are attached onto the core particles, to prepare dispersion liquid containing particles each having the core particle and the resin particles attached thereonto; removing the organic solvent from the dispersion liquid; washing the particles; and drying the particles.
    Type: Application
    Filed: February 1, 2012
    Publication date: October 4, 2012
    Inventors: Atsushi Yamamoto, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomohiro Fukao, Tomoharu Miki
  • Publication number: 20120237253
    Abstract: An electrostatic image developing toner including: toner particles; wherein the toner particles each contain: a core particle including a first resin and a colorant; and fine resin particles each formed of a second resin and existing in a surface of the core particle, wherein part of each fine resin particle is embedded in the core particle to form an embedded region, and the remaining part of the fine resin particle is exposed on the surface of the core particle to form an exposed region, and wherein each toner particle satisfies an expression of R1>R1? where, in a cross-section of the toner particle, R1? denotes an average diameter of openings of the first resin in which the second resin is embedded and R1 denotes an average diameter of the exposed regions.
    Type: Application
    Filed: March 12, 2012
    Publication date: September 20, 2012
    Inventors: Tomohiro FUKAO, Takuya Kadota, Yoshihiro Mikuriya, Tsuyoshi Nozaki, Yoshimichi Ishikawa, Kazuoki Fuwa, Tomoharu Miki