Epson LQ-780 User Manual page 86

Secure it in place by fitting it into the slot on the both sides.
5. Remove the ribbon cartridge.
For details, see "Replacing the ribbon cartridge" on page 99.
6. Pull up the jammed paper from front side.
7. Install the ribbon cartridge.
For details, see "Replacing the ribbon cartridge" on page 99.
LQ-780/LQ-780N User's Guide
Troubleshooting 86