Epson AcuLaser MX20DNF - Manual (Page 218)

Note:
If the paper is stuck in the clear window, open the window to remove the jammed paper.
7. Insert the photoconductor unit slowly all the way in.
8. Insert the developer unit containing the toner cartridge slowly all the way in.
Note:
❏ If you cannot insert the developer unit all the way in, remove and insert the photoconductor unit,
then insert the developer unit again.
Epson AcuLaser MX21/MX20 Series User's Guide
Troubleshooting 218