| 摘要 |
PROBLEM TO BE SOLVED: To diminish nitrogen generation, prevent blind spots, and enable satisfactory delivery by regulating the sum of nitrate ions and nitrite ions contained in an ink composition to less than a prescribed value. SOLUTION: The sum of nitrate ions and nitrite ions contained in this ink composition is regulated to less than 5ppm to obtain a recording ink which, during transportation, storage and use, is free from gas generation and bubbling even in a high-temp. atmosphere and which hence causes no blind spots and attains high printing stability. 0.1-20wt.% water-soluble dye is mixed with a solvent which is water or a mixture of water with a water-soluble organic solvent. The content of the organic solvent is 0-95wt.% and that of water is 10-95wt.%. This ink is obtained by passing an ink through an anion exchange resin to remove nitrate ions and nitrite ions by adsorption or by passing it through an ultrafiltration membrane to remove those ions by filtration. According to need, the ink is degassed and stored in a gas-impermeable container. |
