FIGS. 8A is a magnified perspective view of a substrate, constituting the principal part in the printing head shown in FIG. 7, and FIG. 8B is a magnified perspective view of a portion 8B in FIG. 8A. In these drawings, a substrate 2 is composed for example of silicon, and, on the substrate 2, there is placed a ceiling plate 6 provided with an orifice plate in which plural ink discharge openings (al