INK, METHOD FOR IMPROVING INTERMITTENT DELIVERY PROPERTY OF INK JET RECORDING APPARATUS, INK JET RECORDING METHOD, INK CARTRIDGE, RECORDING UNIT, INK SET AND IMAGE-RECORDING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an ink containing self-dispersible carbon black as a coloring material and excellent in ink jet recording characteristics. SOLUTION: The title ink comprises a coloring material containing at least self-dispersible carbon black having at least one hydrophilic group bonded directly or via another atomic group to the surface of the carbon black and an aqueous medium and has a Ka value measured by the Bristow process of less than 1.5 and the total amount of multivalent cations having a functionality of 2 or higher of 0.05-1 mole/l.