Gravity refilling was introduced as a method of refilling those pesky HP color cartridges. Since HP color cartridges are so susceptible to air pockets when refilling in the conventional manor a better refilling method was devised that all but eliminated the air pockets.

It's not just for HP color cartridges. People have been reporting success refilling Lexmark, Compaq, Epson and Dell cartridges this way. Just about any cartridge that is sponge filled will respond well to gravity refilling.

With gravity refilling you simply remove the plunger from the injector and let gravity suck the ink into the cartridge. Granted this is time consuming but the success rate is hard to ignore. Cartridges that were otherwise impossible to refill successfully responded wonderfully to the gravity method. In combination with the PRIMER tool and Starter Solution, refillers are now able to achieve nearly a 100% successful refill rate with HP and other black and color cartridges.

Here's how to do it.

You need two ink injectors. Remove the plunger from one of the injectors. The plunger is the part that you push on when you inject the ink. Remove it completely from the injector. It snaps out with just a little force. It's a good idea to remove the needle before doing this unless you enjoy acupuncture. :-)

This plunger-less injector is the one that will be injected into the cartridge. Don't put any ink in the plunger-less injector yet, just inject it into the cartridge. Use a 4" needle and get it in as far as you can. The middle chamber in C1823 / C6625 / C6578 / HP51641 cartridges will not go as deep. Don't force it.

Now get your other injector, the one that still has the plunger. Using this injector measure out the proper amount of ink and slowly shoot it into the plunger-less injector's cavity.

The ink will seem like it's not going anywhere at first but let it sit this way for about 20 minutes. It will slowly go into the cartridge. Depending on your elevation and the amount of ink it may take less than 20 minutes.

Repeat this procedure with the other colors.

That's all there is to it. A little patients goes a long way.