Canon imagePROGRAF iPF610 User Manual page 161

If paper is jammed deep in the Paper Feed Slot, remove the Roll Feed Unit and clear the paper jam as follows.
1.
Turn off the printer and remove the Roll Feed Unit from the printer. (→P.153)
2.
Remove the jammed paper from the Paper Feed Slot.
After removing the paper, make sure there are no other scraps of paper in the printer.
3.
Install the Roll Feed Unit on the printer again. (→P.154)
Handling rolls
Handling Paper 147