| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a high concentration layer excellent in water resistance and weatherability by providing a pigment ink containing pigment particles charged with one polarity in an aqueous vehicle, and an ink holder containing at least a functional group chargeable with same polarity as the pigment ink. SOLUTION: An ink dispersed with anions or cations is prepared as an aqueous vehicle and polyurethane foam having an anion and cation group containing a functional group, e.g. -COOH, is prepared as an ink holder. Since the carbon black and the ink holder in an ink are charged with the same polarity of minus or plus, electrostatic repulsion takes place between them and pigment is fed to a print section while being dispersed uniformly into the vehicle without being attracted to the ink holder. Consequently, ink is discharged without causing any clogging and a situation where ink is not discharged despite a large residual quantity can be eliminated.</p> |
