Patent ID: 8814341

Claim:
An ink comprising a coloring material and a lithium ion, wherein; the coloring material comprises a compound represented by the following general formula (I); and a content of the lithium ion in the ink is 3.5 times or more in terms of molar ratio with respect to a content of the compound represented by the general formula (I): in the general formula (I), R 1 represents an alkyl group having 1 to 4 carbon atoms; an alkyl group having 1 to 4 carbon atoms and being substituted with a carboxy group; a phenyl group; a phenyl group substituted with a sulfonic group; or a carboxy group, R 2 represents a cyano group; a carbamoyl group; or a carboxy group, R 3 and R 4 each independently represent a hydrogen atom; an alkyl group having 1 to 4 carbon atoms; a halogen atom; an alkoxy group having 1 to 4 carbon atoms; or a sulfonic group, R 5 and R 7 each independently represent an alkylthio group having 1 to 4 carbon atoms; or an alkylthio group having 1 to 4 carbon atoms and being substituted with at least one kind of group selected from the group consisting of a hydroxy group, a sulfonic group, and a carboxy group, R 6 and R 8 each independently represent an alkylcarbonylamino group having 1 to 4 carbon atoms, R 9 and R 10 each independently represent a hydrogen atom; a carboxy group; a sulfonic group; an acetylamino group; a halogen atom; an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms; or an alkoxy group having 1 to 4 carbon atoms and being substituted with at least one kind of group selected from the group consisting of a hydroxy group, an alkoxy group having 1 to 4 carbon atoms, a sulfonic group, and a carboxy group, and R 11 , R 12 , and R 13 each independently represent a hydrogen atom; a carboxy group; a sulfonic group; a hydroxy group; an acetylamino group; a halogen atom; a cyano group; a nitro group; a sulfamoyl group; an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms and being substituted with at least one kind of group selected from the group consisting of a hydroxy group, an alkoxy group having 1 to 4 carbon atoms; a sulfonic group, and a carboxy group; an alkylsulfonyl group having 1 to 4 carbon atoms; or an alkylsulfonyl group having 1 to 4 carbon atoms and being substituted with at least one kind of group selected from the group consisting of a hydroxy group, a sulfonic group, and a carboxy group.