They control the paper feed. When a sheet of paper is fed into the printer they move down allowing the pick up roller to feed a single sheet. Then they pop up to keep the rest of the paper in its place. Otherwise all the sheets would slide down and several sheets would feed at once.
I had a quick look at the manual but could not see them listed as a separate part. I suspect Epson will only supply them as part of a larger unit. Otherwise you can get a "parts only" printer off ebay.
Unless you are getting multiple paper feed problems, you may not need to replace them at all.
Kind regards
Chris
