Janet Tweedy wrote:

It isn't in Epson's' which is why their ink is cheaper than HP. However
when you buy a new HP ink you get a new nozzle etc. which does help. i
have thrown away several Epson's as there was no way to unblock them and
no repair shop would look at them once they were a few years old, yet
they were generally sturdier built and didn't blow your eyeballs off
with their colours as sometimes happens in HPs.

It is possible to unblock Epson nozzles in a sonic bath. Not everyone
has access to such a device and TBH very few people can tolerate the
noise.