Patent ID: 7198665

Claim:
An ink jet black ink comprising at least a compound represented by the following general formula (I) or a salt thereof, characterized in that the ink jet black ink further comprises at least one moisture-retaining nitrogen compound, and the pH of the ink and the pH of the ink after storing for 10 days in an environment at a temperature of 60° C. are 9.0 or less: wherein R 1 , R 2 , R 3 and R 4 represent each independently a hydrogen atom; a hydroxyl group; an amino group; a carboxyl group; a sulfonic group; an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms; an alkoxy group substituted with a hydroxyl group, an alkoxy group having 1 to 4 carbon atoms, a sulfonic group or a carboxyl group; an alkoxy group having 1 to 4 carbon atoms which may be further substituted with a carboxyl group or a sulfonic group; or an amino group substituted with a phenyl group, an alkyl group or an acyl group, and n represents 0 or 1.