Greetings,
Jam, dirty encoder strip, reset...
The last item usually at fault can be something keeping the ink carrier from moving freely. Be sure to inspect the carrier assembly for any obstructions by lifting the cover and watching as it moves. You can try removing and reseating the inks. If you are not using Canon branded ink cartridges, this too may cause problems.
~Rick
Bay Area - CA
~R5 C (1.0.9.1) ~RF Trinity, ~RF 100 Macro, ~RF 100~400, ~RF 100~500, ~RF 200-800 +RF 1.4x TC, BG-R10, 430EX III-RT ~DxO PhotoLab Elite ~DaVinci Resolve Studio ~ImageClass MF644Cdw/MF656Cdw ~Pixel 8 ~CarePaks Are Worth It
