Why won't my new iMac El Capitan print from Word?
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Try reinstalling, or resetting up any drivers for your printer. You can do this using either built-in mac features, or using any drivers provided by Canon on their website (available here).

For the built-in Apple feature head over to System Preferences.
Then navigate to Printers and Scanners.
Click the - and remove your printer.
Click the + and add follow the steps to re-add your printer.

Hopefully this fixes your issue!