Replace the ink cartridges of your Canon PIXMA MX printer. Which ink cartridges you use depends on your printer. Each cartridge has a unique size and fits in a specific printer. So make sure to check which Canon PIXMA MX printer you have first. You can find it on the front of the printer or in the manual. There are regular cartridges or XL cartridges. With an XL cartridge, you can save money when you print a lot.