wn in FIGS. 2A, 2B, 2C and 2D; [0041]FIG. 4 is a perspective view, partial in section, of an ink head assembled by using the head substrate shown in FIGS. 1A and 1B; [0042] FIGS. 5A, 5B1 and 5B2 are views showing change in an anti-cavitation film of the present invention caused by ink having high Ta erosion ability in accordance with increase in the number of heater driving pulses; [0043]FIG. 6 is