All down the border you are getting head strikes also, note all the dark ink lines at the edge of the margins, on both sides. What do you have the platen gap set to, with this paper it should be widest or wider. Standard will always cause this type of problem. This is much thicker paper than Luster, even though Epson rates the Luster at a 260 W and EEF at 300. You also may have a bit of curl in the paper which might need a bit of de-curling, but I can't tell for sure.
Check your printer for platen gap settings, and look up the Epson recommended printer settings, also should have come on a sheet of paper in the box of paper.