FIGS. 12A, 12B, and 12C are views for explaining an ink reservoir according to the first embodiment, in which FIG. 12A is a sectional front view seen from the front, FIG. 12B is a sectional view taken along the line I???I of FIG. 12A, and FIG. 12C is a sectional view taken along the line II???II of FIG. 12A;