Canon i-SENSYS MF729Cx Important Safety Instructions And Installation Manual page 645

If Printouts are Poor in Quality
If your printouts begin to show any of the following features, one of your toner cartridges is consumed. Replace the nearly empty toner
cartridge even if no message is displayed.
How to Replace Toner Cartridges
White streaks appear
Toner smudges and splatters appear
Checking the Amount Remaining in the Toner Cartridges
Use the procedure below to check the amount remaining in the toner cartridges. It is particularly important to check whether you need
to have a new toner cartridge ready before starting a large print job.
<Device Status>
Amount Remaining in Cartridge
Displays the amount remaining in the toner cartridges. Other internal parts may reach the end of their lifetime before the toner
runs out.
The displayed amount remaining in a toner cartridge can be used only as a guide and may differ from the actual amount.
LINKS
Consumables
Blank space of originals becomes grayish in printouts
<Amount Remaining in Cartridge>
Partially faded
Checking the amount remaining in the toner cartridges
Uneven density