Interpretation
What this message does — and does not — prove
Official meaningCanon defines 5100 as a printer error and specifically tells users to check FINE cartridge installation and whether cartridge-holder movement is impeded.
Do not assumeCode 5100 is not permission to force the cartridge holder or touch the clear encoder film.
Safe sequence
Work through the manufacturer-scoped path
- 01
Cancel the print job and turn the printer off.
- 02
Confirm the FINE cartridges are properly locked in place.
- 03
Check for jammed paper or another obstruction preventing cartridge-holder movement.
- 04
Avoid touching/scratching Canon's clear film/encoder area; power back on only after the path is clear.
Stop / escalate
When not to keep experimenting
Canon says to request repair if the documented checks do not solve 5100.