. "FIGS. 16A to 16C are diagrams illustrating the depth and shape of a guide groove of the ink cartridge according to the embodiment of the invention, in which FIG. 16A is a bottom plan view of the ink cartridge, FIG. 16B is a cross-sectional view taken along a line b-b in FIG. 16A, and FIG. 16C is a cross-sectional view taken along a line c-c in FIG. 16A. FIG. 17 is a diagram showing the motion of a" . . .