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Black ink for ink-jet recording

  • US 7,029,523 B2
  • Filed: 09/29/2003
  • Issued: 04/18/2006
  • Est. Priority Date: 09/30/2002
  • Status: Active Grant
First Claim
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1. A black ink for ink-jet recording, comprising a dye dissolved and/or dispersed in an aqueous medium, wherein the dye has a λ

  • max of 500 to 700 nm and a half value width of 100 nm or more in an absorption spectrum of a dilute solution normalized to an absorbance of 1.0 and is a dye represented by the following general formula (1);

    embedded imagewherein A, B and C each independently represent an aromatic or heterocyclic group, which are substituted or unsubstituted provided that two or more of A, B and C is a substituted or unsubstituted, unsaturated heterocyclic group;

    m is 1 or 2;

    n is 1 or 2,wherein the black ink has;

    a transition metal ion content of 0.1 mmol/l or less; and

    a forced fading rate constant kvis of 5.0×

    10

    2
    [hour

    1
    ] or less, in which the forced fading rate constant kvis is decided by printing a black square symbol of JIS code 2223 in 48-point by using the black ink, measuring a reflection density Dvis of the printed symbol through a status A filter to obtain an initial density, forcedly fading the printed symbol by an ozone fading tester capable of continuously generating 5 ppm of ozone, and determining the time taken until the reflection density Dvis reaches 80% of the initial density.

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