Ink cartridge

An ink cartridge comprising:

• a hollow ink tank body defining a cavity therein, and an outlet port formed on a bottom thereof;
• a cover member connected to a top of the hollow ink tank body;
• wherein the cover has an air vent penetrating therethrough, and a first through-hole protrusion adjacent to the air vent and extending forwards the cavity of the hollow ink tank body;
• a hollow tube connected to the first through-hole protrusion of the cover;
• and
• a pressure regulator arranged inside the cavity of the hollow ink tank body and connected to the hollow tube;
• wherein the pressure regulator includes a holder, a resilient member arranged inside the holder, an elastic plate connected to the resilient member and abutting against the holder, a secure member disposed over the elastic plate, a thin film, sealing the air vent, covered the secure member;
• wherein the pressure regulator further includes a through-hole projection extending outwardly from the holder and the secure member in an alternative manner, for communicating an inside of the holder and connecting the hollow tube, so that the atmospheric air passes through the pressure regulator via the hollow tube after a sealing film is removed.