Patents by Inventor Chikayuki Otsuka

Chikayuki Otsuka 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: 5401604
    Abstract: A positive-type photosensitive resin composition containing a resin which results from reactions between a specific polyepoxide compound, a carboxylic acid compound having a specific phenolic hydroxyl group, a carboxylic acid compound having no specific phenolic hydroxyl group, and 1,2-quinone diazide sulfonyl halide. The resin composition has high exposure sensitivity, is capable of inhibiting swell or dissolution of unexposed areas during the stage of development, and yet retains other favorable properties. The resin composition has also attained short developing time.
    Type: Grant
    Filed: January 31, 1994
    Date of Patent: March 28, 1995
    Assignee: Nippon Paint Co., Ltd.
    Inventors: Chikayuki Otsuka, Mamoru Seio, Kiyomi Sakurai, Kazuyuki Kawamura
  • Patent number: 5367039
    Abstract: Disclosed is a process for preparing a colored polymer without color change between a reactant color dye and an obtained polymer. The process of the present invention comprises polymerizing a vinyl polymerizable monomer (A), and a polymerizable dye (B) prepared by reacting a (meth)acryloyl compound having a group reactive with an active hydrogen, with a dye represented by the formula: ##STR1## wherein R.sub.1 and R.sub.2, which are the same or different, show a hydrogen atom or a group having the formula; ##STR2## (R.sub.3 represents --(CH.sub.2)m-NH.sub.2, or --(CH.sub.2)m-OH, R.sub.4 represents a hydrogen atom, an alkyl group, a cycloalkyl group or an allyl group, n is an integer of 1 to 5 and m is 0 or an integer of 1 to 5), provided that both R.sub.1 and R.sub.2 do not represents a hydrogen atom, X and Y, which are different, --OH or --NHR.sub.1,in the presence of a polymerization initiator, and a color difference between the polymerizable dye and the obtained colored vinyl polymer is within .+-.
    Type: Grant
    Filed: January 12, 1993
    Date of Patent: November 22, 1994
    Assignee: Nippon Paint Company, Ltd.
    Inventors: Naoya Yabuuchi, Chikayuki Otsuka, Akio Kashihara
  • Patent number: 5202215
    Abstract: The present invention provides a toner which substantially excludes off set and blocking of the toner particles, and a process for preparing the toner. The toner is prepared by dispersion-polymerizing a vinyl monomer in the presence of a dispersion polymerization stabilizer, a polymerization initiator and silicone-containing organic resin microparticles in a dispersion medium which dissolves said vinyl monomer, dispersion polymerization stabilizer and polymerization initiator and which does not dissolve said silicone-containing organic resin microparticles and resulting toner particles.
    Type: Grant
    Filed: March 7, 1991
    Date of Patent: April 13, 1993
    Assignee: Nippon Paint Co., Ltd.
    Inventors: Akihiro Kanakura, Koichi Fukuda, Chikayuki Otsuka, Masayuki Maruta, Naoya Yabuuchi
  • Patent number: 5124226
    Abstract: The present invention provides a process for producing toner which has very narrow particle size distribution and contains a uniformity dispersed pigment therein. The process comprises dispersion-polymerizing(I) a pigment paste comprising (A) a pigment grinding agent having basic groups, acidic groups or the both, (B) a pigment and (C) vinyl monomers,(II) a polymerization initiator and(III) a dispersion polymerization stabilizerin a dispersion medium which dissolves said vinyl monomers (C) and dispersion polymerization stabilizer (III) and which does not dissolve polymerized resin particles.
    Type: Grant
    Filed: October 16, 1990
    Date of Patent: June 23, 1992
    Assignee: Nippon Paint Co., Ltd.
    Inventors: Naoya Yabuuchi, Masayuki Maruta, Chikayuki Otsuka, Akihiro Kanakura, Akio Kashihara
  • Patent number: 5059505
    Abstract: Disclosed is a process for preparing polymer particles suitable for electrophotographic toner. The substantially spherical resin particles have a weight average particle size of 1 to 30 microns and contain a carbon atom as main component, a silicon atom in an amount of 1.times.10.sup.-1 to 7% by weight and/or a fluorine atom in an amount of 1.times.10.sup.-2 to 2% by weight. The particles are prepared by polymerizing a polymerizable monomer in an organic solvent having a higher solubility parameter (SP value) than the resultant polymer by at least 1.0 in the presence of a dispersion stabilizer which is soluble in said organic solvent and which has a dialkylsiloxane bond and/or a fluorine atom, and then removing said organic solvent.
    Type: Grant
    Filed: August 20, 1990
    Date of Patent: October 22, 1991
    Assignee: Nippon Paint Co., Ltd.
    Inventors: Akio Kashihara, Chikayuki Otsuka, Naoya Yabuuchi
  • Patent number: 4920187
    Abstract: Disclosed is a process for preparing polymer particles having monodisperse particle size comprising:adding a dispersion stabilizer, a polymerizable monomer and a polymerization initiator to an organic solvent to conduct polymerization, wherein said organic solvent has a solubility parameter (SP value) higher than that of the resultant polymer by at least 1.0 and said dispersion stabilizer is soluble in said organic solvent and has a free radical reactive group of 10.sup.-3 to 1 mmol/g; andremoving said organic solvent.
    Type: Grant
    Filed: January 4, 1988
    Date of Patent: April 24, 1990
    Assignee: Nippon Paint Co., Ltd.
    Inventors: Akio Kashihara, Chikayuki Otsuka, Katsukiyo Ishikawa