My Epson did this, I took the printer apart (the waranty had ran out) and phisicaly cleaned the print head with spirit wipe & a lint free cloth, put it back together. It was good for about 3 weeks before it was blocked again.
I then Took the POS Epson to the dump and bought a HP (you replace the print head when you change the Ink cart on an HP, It makes the carts more expensive, but it's more reliable IMHO)