Disclosed is an ink cartridge for a printer, comprising a body having an opened surface and a predetermined shape to receive ink therein; a cover coupled with the body to define a desired space; and a chamber instrument comprising a filling chamber having a space for receiving a part of the ink in the body, a discharging chamber connected with the filling chamber, an ink transferring channel for moving the ink received in the filling chamber to the discharging chamber, an air guiding hole for guiding air to an inside of the cartridge, an air suction valve for selectively passing the guided air and a pressure regulating valve for regulating an internal pressure of the body.