We own an Epson XP-215 inkjet printer/scanner/copier. We print/copy very seldomly and very few pages each time. One of these days I had to copy a drawing and it came out with wide horizontal white areas. A second copy of the same document was even worse!
In order to better understand the problem I created a simple print with increasing numbers, one per line, and you see the result on the right.
Initially I suspected something had gotten into the printer cylinders and periodically moved paper away from the print head, but further prints were even worse. With the help of an Internet search engine I found and watched some tutorials that showed how to clean nozzles that had dried ink all around.
All you need is a piece of kitchen paper, some liquid for cleaning glass (windows) and thin gloves (else you loose sensitivity in your fingers). The quest for these tutorials is left as an exercise to the reader.
Around the black ink nozzle there was something that looked like dry ink. I removed it with the method mentioned above.
Once I re-installed ink cartridges the first test print came out like this:
Mission completed. 60€ printer saved from dumping within one year from purchase. Happy family members.