Epson B 310N - Manual (Page 23)

Paper Handling 23
4. Load the paper with the printable side down.
Note:
Avoid adding paper in the middle of print jobs. Doing so may prevent the paper from feeding
smoothly.
5. Squeeze the edge guides and slide them against the paper until they click.
Note:
If the legal-size paper cassette is attached instead of the front paper cassette, close its cover.
6. Gently reinsert the cassette into the printer.