Patents by Inventor Kazufumi Tomita

Kazufumi Tomita 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: 6033819
    Abstract: A microcapsule toner comprising an outer shell and a core containing a fixable component, wherein the fixable component has a micro phase separation structure composed of a liquid continuous phase and a disperse phase containing a resin and having a glass transition temperature of not higher than 20.degree. C., and said fixable component contains a block and/or graft copolymer comprising two or more monomer components, at least one of the monomer components being compatible with said disperse phase with the other monomer component or components being compatible with said continuous phase. On pressure application, the toner is instantaneously fixed to provide a fixed toner image which does not fall off or is not destroyed by outer force. The fixable component forms a stable micro phase separation structure which satisfies both fluidity before fixing and hardness after fixing and retains fixability during long-term preservation.
    Type: Grant
    Filed: June 28, 1993
    Date of Patent: March 7, 2000
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Izuru Matsui, Kazufumi Tomita
  • Patent number: 5389490
    Abstract: A capsule toner and a process for producing the same, the capsule toner comprising a core material containing a fixing component, an outer shell covering the core material, and a chargeable substance adhered on the surface of the outer shell, the outer shell containing a polyurea resin and/or a polyurethane resin each obtained from an aliphatic polyisocyanate and an aromatic polyisocyanate. The capsule toner exhibits satisfactory charging properties while surely holding the fixing component inside to provide high quality images with excellent fixing properties.
    Type: Grant
    Filed: July 21, 1993
    Date of Patent: February 14, 1995
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazufumi Tomita, Izuru Matsui, Koichi Takashima
  • Patent number: 5312710
    Abstract: An electrophotographic toner comprising toner particles having adhered on the surface thereof a polymer comprising a monomer unit derived from a fluorine-containing vinyl monomer represented by formula (I) or (II): ##STR1## wherein X represents --COO--, --OCO--, --O--, or a p-phenylene group; R.sub.1 and R.sub.2 each represent a hydrogen atom or an alkyl group having from 1 to 3 carbon atoms; m represents an integer of from 1 to 7; n represents an integer of from 1 to 19; o and p each represent an integer of from 0 to 7; and Y represents a hydrogen atom or a fluorine atom.The toner exhibits satisfactory charging stability against the environment or mechanical forces while having a narrow charge distribution. It can be prepared with a wide choice of materials and without requiring any special reaction apparatus.
    Type: Grant
    Filed: June 30, 1992
    Date of Patent: May 17, 1994
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazufumi Tomita, Yoshihiro Inaba, Koichi Takashima, Tsutomu Kubo, Izuru Matsui
  • Patent number: 5300388
    Abstract: A toner for electrophotography having good electrification stability even under high-temperature and high-humidity conditions is disclosed, which comprises toner particles having a radical-formable substance at least on the surfaces thereof and a copolymer adherent to said surfaces, said copolymer containing as monomer units at least one vinyl group-containing carboxylic acid represented by formulae (I), (II), and (III) and a fluorine-containing vinyl monomer: ##STR1## wherein R.sub.1 represents hydrogen atom or methyl group and n is an integer of 1 to 8.
    Type: Grant
    Filed: July 1, 1992
    Date of Patent: April 5, 1994
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Yoshihiro Inaba, Kazufumi Tomita
  • Patent number: 5215851
    Abstract: A toner comprising capsule particles composed of a core and an outer shell wherein the capsule particles have at least a substance capable of forming a radical at the surface thereof, and the capsule particles have adhered on the outer shell a copolymer comprising a hydrophilic vinyl monomer unit and a hydrophobic vinyl monomer unit. The toner exhibits stable chargeablity against environmental changes with a narrow charge distribution.
    Type: Grant
    Filed: September 4, 1991
    Date of Patent: June 1, 1993
    Assignee: Fuji Xerox Co., Ltd.
    Inventors: Kazufumi Tomita, Yoshihiro Inaba, Koichi Takashima