Epson B 510DN - Manual (Page 27)

Note:
Avoid adding paper before running out of paper. Doing so may prevent the paper from feeding
smoothly.
Note:
If the optional legal-size paper cassette is attached as the front paper cassette, close its cover.
5. Slide the edge guides while pinching their knob to fit the paper you are loading.
B-310N/B-510DN User’s Guide
Paper Handling 27