US 7,370,953 B2
Inkjet recording ink
Takashi Ozawa, Shizuoka (Japan); and Naotaka Wachi, Shizuoka (Japan)
Assigned to FUJIFILM Corporation, Tokyo (Japan)
Filed on Feb. 05, 2004, as Appl. No. 10/771,464.
Claims priority of application No. P.2003-028484 (JP), filed on Feb. 05, 2003.
Prior Publication US 2004/0155947 A1, Aug. 12, 2004
Int. Cl. C09D 11/00 (2006.01)
U.S. Cl. 347—100  [347/95; 347/96; 347/101; 106/31.13; 106/31.6; 106/31.27; 523/160] 7 Claims
 
1. An inkjet recording ink comprising:
an aqueous medium comprising at least one water-miscible organic solvent; and
at least one dye dissolved and/or dispersed in the aqueous medium, wherein said at least one dye has a maximum absorption spectrum λmax at a wavelength range of from 390 nm to 470 nm and a I(λmax+70 nm)/I(λmax) ratio of not greater than 0.4, in which I(λmax) is the absorbance at λmax and I(λmax+70 nm) is the absorbance at λmax+70 nm,
wherein the inkjet recording ink exhibits an accelerated fading rate constant of not greater than 5.0×102 [hour−1], in which the accelerated fading rate constant is determined by printing the ink on a reflection medium to prepare a printed matter, measuring a reflection density through a status A filter to define an initial value of reflection density (DB) in the yellow region by one point between 0.90 and 1.10, and acceleratedly fading the printed matter by using an ozone fading tester capable of always generating 5 ppm of ozone, so as to define the fading rate constant from the time required until the reflection density reaches 80% of the initial value; and
said at least one water-miscible organic solvent satisfies one of the following requirements 1) and 2):
1) said at least one dye has a solubility in all of said at least one water-miscible organic solvent of less than 10 (g/100 g) at 25° C.;
2) said at least one dye has a solubility in at least one of said at least one water-miscible organic solvent of not smaller than 10 (g/100 g) at 25° C., with the proviso that the sum of the weight of the water-miscible organic solvent is not greater than 10% of the weight of the ink.