FIGS. 11A and 11B and FIGS. 12A and 12B are a plan view and a side view respectively, showing a modification of the embodiment of FIGS. 4A-4B; FIG. 13 is a schematic view of a recording head cross-section of the embodiment of FIG. 7; FIGS. 14A, 14B and 14C, FIGS. 15A, 15B and 15C, and FIGS. 16A, 16B and 16C are side views, front views and plan views, respectively, showing further embodiments of th