Epson Stylus Pro 7800 User Manual page 302

Note:
Do not touch the circuit board attached to the print head when
replacing the cutter blade.
8. Slowly take your finger off the side pin. The paper cutter
raises so it can be removed.
Note:
Be careful not to let the cutter or the spring coil pop out of the casing.
9. Carefully remove the old cutter from the printer.
10. Remove the new paper cutter from its package.
11. Make sure the spring coil is inside the cutter holder and if
necessary, reinstall the coil.
12. Fully insert the new cutter into the paper cutter holder in the
direction as shown below.
302
Maintenance and Transportation