HP 21 Black Ink Cartridge

Please do the following steps in refilling HP 21 Black Ink Cartridge. HP 21 is a sponged black ink cartridge and therefore, it has to be refilled with a needle from the holes located on the top and under vacuum in a vacuum chamber. Due to the sponge inside the cartridge, it is crucial that the air should be removed prior to refilling and then the ink can be filled. Otherwise, because of the existing air bubbles inside the sponge, cartridge stops printing after several print outs. Furthermore, we cannot refill the original ink volume.

Steaming the print head is the first step in ink cartridge cleaning

1. Steam the print head with Steam Generator Machine and apply the steam for approximately 10 seconds. It is crucial that the steam gun should be pointed in a perpendicular position. As for all black cartridges, you can get the steam gun closer to the print head for better results.

2. Fix the cartridge into the refill clip and connect to the waste evacuation line. In MIS ink cartridge refill machines, vacuum chambers can also be used to take the waste ink out. In order to do that, connect the cartridge, which is fixed into its refill clip and start the vacuum compressor. While the compressor runs and removes the air inside the chamber, the waste ink will be evacuated, as well.

Insert the needle in a diagonal position through the marked hole with a red circle.

3. Put the cartridge into the vacuum chamber and insert the refill needle through refill hole marked with red circle in a diagonal position. If you insert the needle perpendicularly, you can damage the filter.

In order to see how to connect and refill in different ink refill machines, please refer to the “Ink Refill Machines” menu on the left.

4. Refill 8 ml of black ink.

5. Remove the needle and take the cartridge out of the vacuum chamber.

6. Get a clean and dry tissue and wipe the print head. Afterwards touch the print head to the tissue quickly one after another and check whether the ink is coming. If you see two bold and parallel lines on the tissue as shown in the image, it means that the nozzles are open and if there is nothing wrong with the electronic circuit, the cartridge will print very well.

You should see this bold line after refilling an HP 21 black ink cartridge

7. Fix the cartridge into the printer and get a test print out. It would be a good idea to make a new Word document, which has a content of some text and bold rectangles. For a sample page, please click here. If you get your print out from this Word document, you will be able to see the printing performance of the refilled cartridge.

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8. If the print out test is satisfactory, then we can switch to sealing and packing. In order to prevent the ink from drying, we put a drop of cleaning solution on the print head and wipe it with a clean and dry tissue and put the blue tape over it.

It is crucial to know that in order to prevent any ink dripping, wipe your finger around the print head. Otherwise, the air left between blue tape and print head will make an air pressure and pull the ink out of print head. Such a result will lead ink dripping and drying as the time passes.

While sealing the print head, put one “Pull Off Tape” sticker between blue tape and print head.

For a visual presentation, please refer to “Videos” menu on the left.

9. Eventually, put your refill cartridge in a plastic bag and seal the bag opening.


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