PURPOSE: To obtain the subject ink chemically neutral and excellent in lubricity by using an organic solvent, a coloring agent, and a specified fatty acid ester of polyglycerin as the constituents.

CONSTITUTION: The subject ink contains at least one organic solvent (e.g. ethylene glycol monophenyl ether and propylene glycol monoethyl ether), a coloring agent (e.g. Valifast Black 1802), and a fatty acid ester of polyglycerin of the formula (wherein (n) is 2 or greater; R1, R2, and Rx are each H or 12-22C acyl except for the case where all of them are H at the same time).