If you are encountering a U220B Auto cutter Jam, these are some steps you should try:
Seems pretty obvious, open the Paper cover and ensure that any paper that has crinkled or become stuck.
You should also open the Ribbon cover and check to see if paper has scrunched under the unit.
Check the Auto-cutter Lever
The next step is to check the location of the level under the Paper cover.
First, turn off the printer.
You will need to use a long, skinny pen or pencil to be able to access the knob as it is recessed into the unit.
Rotate the knob to move the silver lever into the centre of the hole.