There are many guides already published, explaining everything except how to properly remove the toner cartridge. Even the original manual does not explain this simple but crucial part as just pulling the cartridge out as recommended does not work and may in fact damage your printer.
To remove the cartridge you need firstly position the drum correctly as explained in the manual. Then you need to release the two hidden lockers by pushing them carefully one by one as shown with a small screwdriver or better with a wooden or plastic pin, around 20 cm long. Pull simultaneously but carefully the cartridge and you can easily remove the empty cartridge. Repeat this step for every cartridge.
The new cartridge just slides in smoothly and locks automatically. Might also work with other Canon printers.
Post time: Jul-14-2017