The following is a general guide on refilling an HP Ink Cartridge:

1. It is important that you refill the cartridge over a surface that is safe in case you happen to spill ink on it. Line the surface with a layer of either an old cloth towel or paper towel. Remove the ink cartridge and put it on the table.

2. Tape over the bottom hole and the top center hole. Make sure that the top center hole seal is air tight. Use black electrical tape as it will provide an air tight seal.

3. Use a clean syringe to fill the fresh ink into the cartridge. A syringe will be included in an inkjet kit.

4. Find the filling hole which will be located on the top or bottom on the cartridge. It is usually sealed with a ball bearing and a plastic film covering. Remove the covering of the filling hole and push the ball bearing into the cartridge. Inject the ink into the top corner hole. When finished, remove the syringe. Use hot glue or hot wax to seal the top corner hole. Insert the correct color ink into the cartridge with the syringe. If you're refilling black ink, use about 20 milliliters. For color ink, use 10 milliliters per chamber.

5. Reseal the filling hole if it is on the bottom of the cartridge Make sure that it is airtight. Squeeze the cartridge sides and insert the plug that should have come with the refill kit. A small amount of ink should trickle from the print head. Seal the top corner hole air tight. Use a hot wax or hot glue. Black electrical tape will often work as well. Squeeze the cartridge just before sealing to set up the vacuum. Remove the tape. Set on a paper towel for an hour as a drip safeguard. There will be a few drips until the vacuum becomes stable.

6. Let the cartridge stand with the print head down for a couple of minutes before putting it back in the printer. This will pull out excessive ink and balance pressure in the cartridge.

It is important that you do not stick a large sharp object into the top center hole as the cartridge will continue to leak. If the seal that is applied to the fill hole is not air-tight, the cartridge will leak. If you have a leak around the bottom hole, you may be able to fix it with some glue. Many experts recommend purchasing a refill kit as it has the correct equipment and guide on how to refill each specific cartridge.

The above tips are designed to make the refilling process of your HP inkjet cartridge much easier and less messy. Refilling an HP inkjet cartridge is much cheaper than purchasing a new cartridge.

Information Source: ehow.com/refill-hp-inkjet-cartridges