You can run
a Power Cleaning using a utility on your Windows or Mac computer.
Note: After
running a Power Cleaning, you must turn off the product and wait at
least 12 hours before running another Power Cleaning.
If
print quality has not improved after running Power Cleaning, wait
for at least 12 hours without printing, and then print the nozzle
check pattern again. Run Print Head Cleaning or Power Cleaning
again depending on the printed pattern. If quality still does not
improve, contact Epson support.