Patents by Inventor Takashi Hirasa

Takashi Hirasa 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: 5859092
    Abstract: A recording liquid containing an aqueous medium, a pigment and a polymer, wherein the polymer comprises at least one polymer containing a repeating unit A having at least one of a carboxyl group and an acid anhydride group and an allylether unit B of the formula (I), ##STR1## wherein R.sub.1 and R.sub.2 are a hydrogen atom or a substituted or unsubstituted C.sub.1 -C.sub.5 alkyl group, R.sub.3 is a hydrogen atom, an alkyl group, an alkylcarbonyl group, an alkenyl group, an alkenylcarbonyl group, an aryl group, an arylcarbonyl group, an aralkyl group, an aralkylcarbonyl group, a cycloalkyl group, a cycloalkylcarbonyl group, a heterocyclic group or a carbonyl group having a heterocyclic group, and these groups other than a hydrogen atom may have a substituent, and n is from 1 to 50.
    Type: Grant
    Filed: April 18, 1997
    Date of Patent: January 12, 1999
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Takashi Hirasa, Hiroshi Takimoto, Yukichi Murata, Hiroshi Mikami, Shoji Toki
  • Patent number: 5738714
    Abstract: Disclosed is a recording liquid comprising a carbon black dispersed in an aqueous medium, which is characterized in that a toluene extract of the carbon black has an absorbance of 0.05 or less at .lambda.max within the range of from 330 nm to 340 nm or at 337.5 nm when the toluene extract does not have .lambda.max within the range of from 330 nm to 340 nm. The recording liquid can be used in ink-jet recording in high safety. During and after long storage of the recording liquid, the carbon black does not precipitate out. Using the recording liquid, reliable recording can be attained with good jettable durability of the liquid. Even when the recording liquid is recorded onto ordinary papers, high-quality images with good water-fastness and good light-fastness can be formed. The recording liquid is especially suitable for thermal ink-jet recording systems.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: April 14, 1998
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Takashi Hirasa, Hiroshi Takimoto, Makoto Ishizu, Katsuji Honda
  • Patent number: 5725644
    Abstract: A black-type recording liquid, even when used for ink-jet recording instruments or for recording with ordinary writing instruments on plain paper, is capable of forming a recorded image with high printing quality: high density, excellent color tone, and excellent water and light resistance, and is highly stable when stored for a long time.
    Type: Grant
    Filed: July 12, 1996
    Date of Patent: March 10, 1998
    Assignee: Mitsubishi Chemical Corp.
    Inventors: Hideo Sano, Hiroshi Takimoto, Toru Nishimura, Masahiro Yamada, Takashi Hirasa
  • Patent number: 5713992
    Abstract: The present invention relates to a recording liquid characterized by comprising an aqueous medium and at least one monoazo dye selected from dyes, the free acid forms of which are represented by general formula {I}: ##STR1## (wherein R.sub.1, R.sub.2, and R.sub.3 each independently represents a substituted or unsubstituted alkyl group having 1 to 9 carbon atoms, an alkoxy group having 1 to 9 carbon atoms, a halogen atom, a hydrogen atom, a hydroxyl group, a substituted or unsubstituted carbamoyl group, a substituted or unsubstituted sulfamoyl group, a substituted or unsubstituted amino group, a nitro group, a sulfonic ester group, a sulfonyl group, a COOH group, or a carboxylic ester group;m represents a number of 0, 1, or 2; andR.sub.4, R.sub.5, R.sub.6, and R.sub.
    Type: Grant
    Filed: January 13, 1997
    Date of Patent: February 3, 1998
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Nobuyoshi Satoh, Takashi Hirasa, Yukichi Murata
  • Patent number: 5542969
    Abstract: A recording liquid containing carbon black dispersed in an aqueous medium, wherein the volume ratio of carbon black having a particle size of at least 0.2 .mu.m to the total carbon black is at least 50% by volume, and the volume ratio of carbon black having a particle size of at least 0.6 .mu.m to the total carbon black is at most 20% by volume.
    Type: Grant
    Filed: September 26, 1995
    Date of Patent: August 6, 1996
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Takashi Hirasa, Hiroshi Takimoto, Nobutake Mise