| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain the subject ink, containing carbon black oxide excellent in water-dispersibility as a coloring agent, capable of printing without clotting a nozzle when used for ink jet recording and having a concentration capable of smoothly writing down even when a fine pen is used. SOLUTION: This ink contains carbon black oxide stably dispersing into water. This carbon black oxide is prepared by oxidating carbon black with a hypohalogenous acid and/or its salt and at least a part of acidic moiety existing on the surface of it is combined with an amine compound (preferably a water-soluble volatile amine) to form an ammonium salt. In order to obtain this carbon black oxide, carbon black finely dispersing into water is oxidized with the hypohalogenous acid and/or its salt and then at least a part of the acidic moiety existing on the surface of the resulting carbon black oxide is preferably neutralized with the amine compound.</p> |
