How to Refill an HP 940XL Ink Cartridge

1. Put on the rubber gloves. Place the HP 940XL ink cartridge on some paper towels to soak up any spilled or splattered ink.
2. Locate the horizontal line in the cartridge, where the two cartridge housing sections meet. Use the knife to cut through the front ink cartridge label at this horizontal line. Leave the back label intact.
3. Insert the tip of the flat blade screwdriver into the horizontal line and gently pry the two sections of the plastic cartridge housing apart, allowing them to remain attached by the back cartridge label.
4. Move the exit port stem aside and locate the fill hole. Remove the small ball from the fill hole with the tip of the knife and set aside.
5. Fill your refill kit syringe with the appropriate color ink for the cartridge. A full ink bottle will be necessary to fill the standard size HP 940XL cartridge.
6. Insert the syringe needle tip into the fill hole. Do not puncture the interior ink bag. Depress the syringe plunger to inject ink into the cartridge.
7. Tilt the cartridge to allow any air bubbles out of the interior ink bag. Suction a small amount (approximately 1/4 tsp.) of frothy ink and air from the fill hole with the syringe.
8. Replace the small ball into the fill hole and press it into place with the tip of a retracted ballpoint pen. Snap the two halves of the plastic cartridge housing back together.
9. Turn the cartridge upside-down and squeeze it gently to check for leaks. If the cartridge leaks, then the interior bag has been punctured or the refill hole ball is damaged, meaning that the cartridge is unusable and must be thrown away. If there are no leaks, the HP 940XL ink cartridge is ready for use and may be installed in your HP printer.