Ink refilling apparatus and method for cartridge of ink jet printer

An ink refilling apparatus for a cartridge of an ink jet printer for refilling a cartridge including a case storing ink, an injection hole through which the ink is injected into the case and a nozzle for ejecting the ink, comprising:

• an injector including a cylinder containing the ink, an ejecting protrusion formed integrally at an end of the cylinder and having an ejection hole, an enclosing protrusion formed integrally at the end of the cylinder while surrounding the ejecting protrusion and being spaced apart therefrom and formed with a female screw around the inner periphery, and a piston inserted into the cylinder for ejecting the ink in the cylinder;
• and
• a refill holder including a base onto which the cartridge is fittingly seated, a first supporting wall which is bent vertically from an end of the base to contactingly support one surface of the cartridge and is formed with a mounting hole which communicates with the injection hole of the cartridge, a second supporting wall which is bent vertically from the other end of the base to contactingly support the other surface of the cartridge, and a coupling member which is fitted into the mounting hole,
• the coupling member including a coupling protrusion which is insertedly bonded to the mounting hole, a contacting plate which is integrally formed at the coupling protrusion while being larger than the coupling protrusion and contacts the outer surface of the first supporting wall, an inserting protrusion which is integrally formed at the contacting plate and formed with a male screw around the outer periphery to be teeth-engaged with the female screw of the injector, and an ink injection passage which is formed through the coupling protrusion, the contacting plate and the inserting protrusion in an axial direction and communicates with the injection hole of the cartridge.