| 摘要 |
<p>An ink for ink jet recording comprises an azo dye with a lambda max in an aqueous solution of 390-470 nm; and an I(lambda max + 70 nm) / l(lambda max) ratio of = 0.4, in which l(lambda max) is the absorbance at lambda max and I(lambda max + 70 nm) is the absorbance at (lambda max + 70 nm). The dye is dissolved and/or dispersed in an aqueous medium. The ink has a forced fading rate constant of = 5.0 x 10 -> 2> [hour -1>] : An ink for ink jet recording comprises an azo dye of formula of A-N=N-B (where A, B = a heterocyclic group which may be substituted) with a lambda max in an aqueous solution of 390-470 nm; and an I(lambda max + 70 nm) / l(lambda max) ratio of = 0.4, in which l(lambda max) is the absorbance at lambda max and I(lambda max + 70 nm) is the absorbance at (lambda max + 70 nm). The dye is dissolved and/or dispersed in an aqueous medium. The ink has a forced fading rate constant of = 5.0 x 10 -> 2> [hour -1>]. The forced fading rate constant is decided by printing the ink on a reflection type medium, measuring a reflection density through a Status A filter, specifying one point having a reflection density (DB) in a yellow region of 0.90 to 1.10 as an initial density of the ink, forcedly fading the printed matter by use of an ozone fading tester that can regularly generate 5 ppm of ozone, and determining the time taken until the reflection density reaches 80% of the initial density. The total amount of cations in the ink except for a monovalent metal ion, a hydrogen ion, an ammonium ion an organic quaternary nitrogen ion and an ion produced by the proton addition to a nitrogen atom in a basic organic material is = 0.5 wt.%. An independent claim is also included for ink set comprising the ink for inkjet recording.</p> |
