| abstract |
[PROBLEMS] To minimize the change in drive pulse and the change in output image even when held for a long period of time, such as during distribution or when an ink cartridge containing ink is installed in a printing apparatus. Providing ink-jet ink and ink cartridges that have characteristics, printing durability, and low temperature rise associated with printing. An ink cartridge having a thermal ink jet head provided with a heat generating part for discharging ink from an ejection port and containing ink, wherein a surface of the heat generating part in contact with ink is made of silicon, Having a protective layer containing at least one selected from oxides, nitrides and carbides, and the ink contains any of a polyvalent carboxylic acid and a salt thereof; An ink cartridge having a total of 0.001 to 0.5 mmol / l and the ink for the head. [Selection] Figure 1 |