Select System Preferences from the Apple menu > Printers & Scanners (or Print & Scan, Print & Fax) and then select the printer.
Click Options & Supplies > Utility > Open Printer Utility.
Click Power Cleaning.
Follow the on-screen instructions.
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 Cleaning or Power Cleaning again depending on the printed pattern. If quality still does not improve, contact Epson support.