Epson Stylus Photo RX600 Quick Start Manual page 4

Insert a sheet of 8.5 × 11-inch plain paper—short edge first—
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against the right edge of the sheet feeder and under the tabs on
the edge guides.
5 Press the sides of the left edge guide together and slide it against
the paper (but not too tightly).
6 Flip the feeder guard back over the paper.
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