Epson WorkForce WF-3010DW User Manual page 22

User's Guide
Note:
Make sure the number of envelopes does not exceed the limit.
"Selecting Paper" on page 14
&
D
Slide the edge guides to the edges of the envelopes and check that the envelopes are not sticking out from the end
of the cassette.
Note:
Even if you do not feel a click, slide the edge guides to the edges of the envelopes.
E
Keep the cassette flat and slowly and carefully reinsert it all the way into the product.
Paper and Media Handling
22