Patent ID: 7144452

Claim:
An ink jet black ink comprising at least a coloring material and a water-soluble organic solvent, wherein the coloring material comprises a compound represented by the following general formula (I) or a salt thereof, and wherein the water-soluble organic solvent is a water-soluble organic solvent having a relative permittivity of from 30.0 or more to less than 70.0 at 20° C. and capable of dissolving the compound represented by the following general formula (I) or a salt thereof, by 1.0 mass% or more at 25° C., and is in a content of 50.0 mass% or more with respect to the total content of all water-soluble organic solvents contained in the ink jet black ink: wherein R 1 and R 2 each independently represent a hydrogen atom, a hydroxyl group, an amino group, a carboxyl group, a sulfonic group, an alkyl group having 1 to 4 carbon atoms or an alkoxyl group having 1 to 4 carbon atoms; and R 3 and R 4 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, a hydroxyl group, an alkyl group having 1 to 4 carbon atoms which may be substituted with a hydroxyl group or with an alkoxyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms which may be substituted with a hydroxyl group, with an alkoxyl group having 1 to 4 carbon atoms, with a sulfonic group or with a carboxyl group, or an amino group which is substituted with an alkyl group or with an acyl group; and n represent 0 or 1.