| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an ink that can achieve both the reliability of ink that prevents ink retention in a cap and is excellent in storage stability, and the image characteristics of excellent image density and bleeding resistance. <P>SOLUTION: The ink includes a self-dispersible pigment, a salt, a polyoxyethylene alkyl ether and a water-soluble organic solvent. The self-dispersible pigment is a pigment to the surface of a particle of which a functional group containing at least a phosphonic acid group is bonded, the introduced amount of the functional group is 0.10 to 0.33 mmol/g. The salt is constituted by combining a cation such as alkali metal ion and ammonium ion with an anion such as Cl<SP POS="POST">-</SP>, SO<SB POS="POST">4</SB><SP POS="POST">2-</SP>, and HCOO<SP POS="POST">-</SP>. The concentration of anion × the valence number of anion of the salt in the ink is 0.005 to 0.06 mol/L. The water-soluble organic solvent includes glycerol, the content of which in the ink is 35 to 78 mass% based on the total content of the water-soluble organic solvent in the ink. <P>COPYRIGHT: (C)2012,JPO&INPIT |
