How HP Printhead Self-Cleaning Works: Dissect Waste Ink Assembly 8022 / 8025 / 8020

Today, we will talk about how the HP printhead self-cleaning works. Printhead cleaning is pretty important for the printer to work correctly. If your printer malfunctions, I hope you have the ability to troubleshoot, but this is just the basics of what each part is and how they work. You can purchase onehere through BCH Technologies if you need a waste ink assembly.

Function of the Gear

First, let’s discuss this thing that goes back and forth and up and down. This ladder is attached to a gear, so this platform can go back and forth when the gear turns. When you go back and forth, it cleans the printhead with this rubber blade. So, if you have dried ink on the bottom of the printhead, this thing can remove the dried inks.

How the Vacuum Works

The second function is this part that can rise and attach to the bottom of the printhead, and so you can use a vacuum to suck ink out of the base. You may wonder why you get just two vacuum chambers but four tubes. I’ve drawn a diagram showing how it works. If you need this diagram, you can text HPWASTE to (855) 452-8332, and I will text you a link through which you can download this image.

Here’s the part that we just talked about. You have four holes and two in the middle that are lower, so that’s where the waste ink gets sucked out. On the left side is the color ink, the CMY, and on the right is the black ink, so I use the blackest color for the black ink. I colored it black so that it’s easier for you to see.

Using the Peristaltic Pump

After the ink gets sucked out, it goes to this peristaltic pump. Peristaltic pumps are widely used in the printing industry. If you look inside, there’s not much to see—you will just see a tube with a roller, so basically, you turn the motor on, and the roller will rotate and massage the tube. When this tube gets massaged, the ink is squeezed out.

The advantage to this is the mechanical part never touches the ink. The ink always flows in a tube. This is different from centrifuge and diaphragm pumps. Below the peristaltic pump is the motor part. These discs have tiny marks on them, so when it rotates, it goes through an optical sensor that can measure the pump's rotation speed.

So, you get the two tubes coming in and two lines going out. HP uses a white tube for the color waste ink and a black one for the black ink. The ink gets dumped out into this little box, and the white tube, which is the colored ink, gets dumped into the front section, and the black ink is downloaded to the lower section of the box.

Finding the Air Tubes

Now you understand the bottom, top, and side parts, and why the set box gets two sections, but what is this other thing? These are actually air tubes. It controls whether the HP wants to suck ink from the left or right of the chamber. For example, if HP wants to suck ink from the left side, it will open the air hole on the right side, so the right side doesn’t have any suctions.

Another two air tubes are connected to this selection lever. The printhead assembly pushes the selection lever, and only one tube is opened each time, so you always clean one side of your printhead.

Final Thoughts

Hopefully, you enjoyed this video. Let me know if you know how the Epson waste ink assembly works. Epson designed a much more complex assembly, and because of that complexity, I think the faulty rate is higher than for HP.