Inkjet recording ink

1. An inkjet recording ink comprising an aqueous medium having dissolved therein a dye represented by the following formula (I), which is water-soluble and contains a lithium ion as a counter ion,

wherein the total amount of a cation in said ink except for a lithium ion, a hydrogen ion, an ammonium ion, an organic quaternary nitrogen ion and an ion produced by proton addition to a nitrogen atom in a basic organic material is 0.5 wt % or less:

wherein X 1 , X 2 , X 3 and X 4 each independently represents —SO-Z, —SO 2 -Z, —SO 2 NR 1 R 2 , a sulfo group, —CONR 1 R 2 or —CO 2 R 1 , and at least one of X 1 , X 2 , X 3 , and X 4 represents —SO 2 -Z or —SO 2 NR 1 R 2 ; Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted heterocyclic group; R 1 and R 2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted heterocyclic group, and when a plurality of Zs are present, the Zs may be the same or different; Y 1 , Y 2 , Y 3 and Y 4 each independently represents a monovalent substituent, and when a plurality of X 1 s, X 2 s, X 3 s, X 4 s, Y 1 s, Y 2 s, Y 3 s or Y 4 s are present, the X 1 s, X 2 s, X 3 s, X 4 s, Y 1 s, Y 2 s, Y 3 s or Y 4 s may be the same or different; a 1 to a 4 and b 1 to b 4 represent the number of substituents X 1 to X 4 and Y 1 to Y 4 , respectively; a 1 to a 4 each independently represents an integer of 0 to 4 but all of a 1 to a 4 are not 0 at the same time; b 1 to b 4 each independently represents an integer of 0 to 4; M represents a hydrogen atom, a metal atom, or an oxide, hydroxide or halide thereof.

2. The inkjet recording ink as described in claim 1 , wherein the dye represented by formula (I) is a dye represented by the following formula (II):

wherein X 11 to X 14 , Y 11 to Y 14 and M have the same meanings as X 1 to X 4 , Y, to Y 4 and N in the formula (I), respectively, and a 11 to a 14 each independently represents an integer of 1 or 2.

3. The inkjet recording ink as described in claim 1 , which further comprises a hydrogen ion.

4. The inkjet recording ink as described in claim 1 , wherein the cation in said ink except for a lithium ions 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 at least one selected from the group consisting of a potassium ion, a sodium ion, a cesium ion, a magnesium ion, a zinc ion, a calcium ion, a strontium ion, an aluminum ion and a transition metal ion.

5. The inkjet recording ink as described in claim 1 , wherein the cation in said ink except for a lithium 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 at least one of a potassium ion and a sodium ion.

6. The inkjet recording ink described in claim 1 , wherein the dye has an ionic hydrophilic group.

7. The inkjet recording ink described in claim 1 , wherein the dye has at least two hydrophilic groups within one molecule.

8. The inkjet recording ink described in claim 1 , wherein the dye has an ionic hydrophilic group selected from the group consisting of a carboxyl group, a phosphono group and a sulfo group.

9. The inkjet recording ink as described in claim 2 , wherein in formula (II) Y 11 to Y 18 each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, a cyano group, an alkoxy group, an amido group, a ureido group, a sulfonamide group, a carbamoyl group, a sulfamoyl group, an alkoxycarbonyl group, a carboxyl group or a sulfo group.

10. The inkjet recording ink as described in claim 2 , wherein in formula (II) Y 11 to Y 18 represents a hydrogen atom.

11. The inkjet recording ink as described in claim 1 , wherein the dye represented by formula (I) is present in an amount of 0.2 to 20 wt %.

12. The inkjet recording ink as described in claim 2 , wherein the dye represented by formula (II) is present in an amount of 0.2 to 20 wt %.

13. The inkjet recording ink as described in claim 1 , wherein glycerin is present in an amount of 10 to 50 wt %.