Have you tried using a dilute ammonia solution to clean the head?
I'm not sure exactly how this is done with an Epson's piezo
arrangement, but I seem to recall that someone had advised soaking a
small pad with the solution and inserting it after removing the
cart. Might have to sit there for a while to fully dissolve the
residue.
The ink that is used during a cleaning cycle winds up in an
absorbent pad, and after a number of cleanings, your printer is
likely to shut down. The good news is that you can remove and clean
or replace this pad (by disassembling the printer), and you can also
reset the printer by (as I recall) holding the paper button down for
at least 10 seconds while powering on. Either that, or get the free
"SSCServe" program that should include a reset function.