What's this?

Refill Instructions
HP 51641, C1823, and C6578 Tri-Color Cartridges

Updated November 28, 2001

Many HP Deskjet Printers, Officejets, Printer/Scanner/Copiers, and CertainPlotters.


The ink in this cartridge is retained because the cartridge hasan internal sponge. Refilling this one can be a bit tricky, sobe sure to follow the instructions carefully.

There are two key issues with this cartridge:


Please note that the ink used in the 51641 cartridges is different than the ink which is used in the C1823 and the C6578 cartridges. Do not mix the inks, or your printing performance will suffer.

51641 Inks

  • WJ-243 Cyan (Blue)
  • WJ-637 Magenta (Red)
  • WJ-717 Yellow

C1823/C6578/#25 Inks

  • WJ-276 Cyan (Blue)
  • WJ-668 Magenta (Red)
  • WJ-745 Yellow


  1. Put the cartridge on some paper towels in an area whereyou can tolerate a spill.

  2. Look at the top of the cartridge. You will notice threeentry points with plugs in them. (if you look carefully at the plugs, you will see that they have molded air channels in the side of them. This is why we do not reseal the top after refilling.)

    A few of these cartridges don't have these holes. If your cartridge doesn't, you willneed to drill three 1/16 inch (1.5mm) holes, one over each colorchamber if you have one of these odd cartridges.

    (An alternative plan is to drill holes in the front (label side) of the cartridge, near the bottom of the cartridge. This allows the ink to be delivered directly to the printhead, which avoids trapping air under the ink. If you decide to use this method, you will need to reseal these holes to prevent leaking.)

  3. Push the plugs into the cartridge with a ball point penor similar device. Warning: Ignore the color bars on the label of the cartridge. These do not indicate the sequence of colors in the cartridge.

    Typically, when looking from the side withthe copper contacts, the colors from left to right are cyan (blue), magenta (red),and yellow. However, to determine for sure which color ink is in whichchamber, insert a toothpick or unbent paperclip and check the color of the ink onthe toothpick when it is withdrawn.

  4. On this cartridge, it is important to only fillthe color which is low, since over-filling can lead to severalproblems.

    If a large drop of ink comes out of the bottom of the cartridge, immediately blot this with a paper towel to prevent the ink from migrating upward into a less full chamber and causing cross-color contamination.

    Insert the syringe needle fully into the hole, angling towardthe front (the side with the copper strips). We suggest that you tape over the other two holes whilefilling to avoid accidental color contamination.

    The syringe must be inserted as deeply as possible so that the ink will fill the sponge from the bottom up, driving the air up and out.

  5. Inject 8-10 ml (1/4th of a syringe bottle) of the inkinto the fill hole slowly. Go slowly or you willdevelop air dams in the lower sponge which will block ink flow. Donot add additional ink!

  6. If the ink starts to come out of the print head, the cartridgeis over full. Immediately blot the ink from the bottom of thecartridge to prevent it from seeping up into the other chambers.

  7. Remove your needle from your syringe. Set aside the needle.

  8. Do this step over a sink! Mate the syringe (without needle) to the hole on the top of the cartridge. Force air down into the hole to pressurize the chamber slightly. (This will force ink downward and into the space between the printhead and the nozzle plate, priming the printhead.) When a small drop of ink comes out of the printhead, stop forcing in air and wipe away the drop immediately.

  9. Remove any tape on any holes. (The holes on top must be open during printing.) You maytape them over for longer storage or during transport. (If you look carefully at the original plugs, you will see a small air passage molded into them which allows air to vent into the cartridge.)

  10. Set above a paper towel for a few minutes as a drip precaution. Do not allow the cartridge to touch the paper, since the paper will draw out the ink.

  11. For best results, let sit overnight before using.

To Clean the Printhead

  1. Only clean the printhead if you get poor print quality or no print.
  2. Be sure that you don't have an air bubble or nozzle plate problem.
  3. Follow the directions in the printer manual to run the cleaning routine.
  4. If this doesn't work, take the cartridge to the nearest hot water faucet.

To Clean Your Sink

The ink is water-soluble. Use plenty of soap and warm water. You may also need to use Comet or a similar cleaner if the stains persist.

To Clean Your Hands

On hands, the best substance to use is Ink Be GoneTM, a specially developed hand cleaner available from ACSI Bulk Inks. (To place an order, Click Here.)

To Place An Ink Order

You can telephone us at 1-888-728-2465 (USA Tollfree) or 1+740-374-9949. You can also Order Online or by other ways including by Fax, or by Postal Mail, or by EMAIL.
What's this?
Copyright 1999, 2001 Automation Consulting & Supply, Inc.
Contact us at 1-304-622-5086 or email us at Order Email.
Main Ink Page | Other Refill Instructions and Help | Home