I have two 8620er at full work here since 10 or more? years.
The defective print head seems to be a "wanted" standard problem for these printers after 10 or 20.000 printouts.
and I tried a lot of ways to "repair" that in the past. There are many videos on youtube for how to reanimate (clean) the print head,
but none of them ever worked for me. Also buying a (chinese) new print head did not fix the problem.
Some month ago I was lucky in buying a badly used 8620er for 50eu on eBay, I just wanted to swap the print head,
but it turned out that it was used for 500 prints only, so for now, now I have a new printer 🥰
Still looking for more machines