| abstract |
An ink cartridge includes a thermal ink-jet head provided with a heat generating portion that generates thermal energy for ejecting the ink from an ejection opening, in which: the heat generating portion has, on its surface in contact with the ink, a protective layer containing at least one selected from the group consisting of a silicon oxide, a silicon nitride, and a silicon carbide; and the ink contains a substance that dissolves the protective layer and a compound represented by (R 2 ) n A—. . . —N(R 1 )C(O)R 3 (R 4 )—(A) where A represents alkylene or alkenylene which forms a ring with a nitrogen atom, a carbonyl group and R 3 , R 1 and R 4 each represent hydrogen atom, hydroxyl, alkyl, alkenyl, acyl, carbamoyl, carboxyl or sulfonyl, R 2 represents a group bonded to an arbitrary carbon atom of A and represents hydrogen atom, hydroxyl, alkyl, alkenyl, acyl, carbamoyl, carboxyl or sulfonyl, n represents 0 to 4, and R 3 represents carbon or nitrogen atom, and a content X (% by mass) of the compound satisfies 1≦X≦30. |