Epson Printers are renowned for clogging the printhead. This happens regardless of the type of ink cartridges used and can just as easily occur with genuine or compatible printer ink. The Epson printhead cannot be removed which makes cleaning an even more difficult task. Although it sounds odd "Windex" (window cleaner) can actually be used to break down the dried ink which remains inside of the printhead.
Windex consists of around 50% ammonia which is the key ingredient for cleaning the printhead. Simply remove the cartridges and spray some Windex in the offending holes where the ink flows into the printhead itself. You can leave this for several hours or even overnight untill all dried ink inside the printhead is dissolved. Next re install the cartridges and keep printing untill you are satisfied with the print quality. Printhead Cleaning Kits can be purchased here.
Instead of going through the lengthy process of different cleaning methods let me simply refer you to some very interesting and helpful links. Cleaning an Epson Printhead
The following link also gives a very detailed reasoning as to why the Epson Printheads clog so easily! How to Unclog Epson Print Heads
The following link is a video of how to clean an Epson printhead ! Cleaning a Blocked Epson Printhead Video
The following link is interesting as it gives illustrations of how the actual Epson Printhead functions! Unclogging an Epson Print Head