It's 2023 and I have a circa 2011 Canon MG6120 printer. We print pretty infrequently (a few pages every few weeks), and use the copy/scan functionality even more rarely. Given the relative light use in my household, I've been intent to squeeze every last bit of life. When I got the U052 error, I was extremely frustrated since my ink cartridges were pretty new. But given that the alternative was buying a new printer, I decided to try to fix the problem, and it worked. Here's what I did:
1) Remove the print head. It's pretty easy. Watch some videos online. First remove the cartridges, then flip the lock, then maneuver the head out.
2) Clean the print head. In a bowl or plastic bin, pour enough 99% isopropyl alcohol in to dunk/submerge the print head and leave it in there for 2-5 minutes. You can shake the print head around and watch the ink come out. If there's still color on parts where the cartridge makes contact, repeat. Then let the printhead dry for a few hours. 24 hours is probably ideal, though a couple of hours might be fine. (the alcohol evaporates pretty quickly and shouldn't damage the electronics bits. And even if it did, just think that the printer was already broken beyond repair anyway!)
3) Clean inside the printer. While you're soaking the print head, unplug the printer so the guide remains in place. With 99% isopropyl alcohol and a rag/microfiber cloth/sturdy paper towel, wipe up the metal contacts in case some excess ink or oxidation formed on the contacts (pretty unlikely, but keep reminding yourself that the printer is basically garbage at this point)
4) After 24 hours, reinstall the print head, first without ink. You may still get U052 again, or perhaps a new error message (No ink cartridges found or something like that).
If you still get U052, turn it off, and wait another day. If it just asks you for ink cartridges, insert the old ink cartridges and see if you get past U052. If you get that error again, try installing BRAND NEW ink cartridges (you can try 3rd party ink - remind yourself that the printer is basically unrepairable garbage, so you want to invest a minimum amount to see if you can get it to work).
5. Congratulations. If you're like me, your printer will initialize like normal and be ready for printing. At first, my black ink didn't print. So I ran a deep clean cycle. Voila! That did the trick. My printer has been working perfectly for about a week - I've made a point of printing a few pages every day since and it continues to work.
It's really not a lot of work. Taking out the printhead takes about 1 minute. 99% isopropyl alcohol can be purchased cheap at most drug stores or dollar stores. Soaking doesn't take much effort at all. You're mostly just setting and forgetting. And if it works, you just saved yourself $50-200, depending on your model Canon inkjet printer. Good luck!
