Installing Canon MX420 Driver on Mac OS X 10.12 Sierra
The Mac Post Presents Links on How-to Download and Install the Canon MX420 Series Printer/Scanner Drivers on Mac OS X 10.12 Sierra Unix/BSD Desktop.
Your Mac should Automaticallly Installs Canon MX420 Drivers, it is enough to Check for Updates.
Check for Updates on Mac 10.12 SierraMac OS X Drivers Updates
Then simply Connect and Start to Use the Canon MX420 Printer.