I have printed out the Nozzle Check and things seem good but the yellow is hard to see on any paper I try. But looking careful I can see under the light that they print as unbroken as the other five colors do so I think they are not in a problem where they are clogged.
It is fortunate to see that the R280 does not clog yet at all when I use it. Older Epson ink jet model did clog often.
Print Head is not part of the ink cartridges so how do you make sure it is not wearing out?