Old Epson printer software

To completely remove your old Epson printer software and resolve conflicts with your new Canon printer, you need to remove the printer from your system settings and delete its utility software.

Here is how to clean it off your iMac:

Remove the Epson Printer from System Settings

• Click the Apple menu () in the top-left corner and select System Settings.
• Scroll down and click on Printers & Scanners in the sidebar.
• Select your old Epson printer from the list.
• Click the Remove Printer (or minus -) button and confirm.

Uninstall the Epson Software Applications

• Open Finder and go to your Applications folder.
• Look for an Epson folder. If you see one, open it and check for an Epson Uninstaller app. Run it if it's there.
• If there is no uninstaller, look for apps named Epson Software, Epson Scan, or similar utilities.
• Drag those Epson folders and apps directly to the Trash.

Clear Remaining Background Files

Printers often leave behind background files that can cause driver conflicts.

• Open Finder.
• In the top menu bar, click Go > Go to Folder...
• Type or paste ~/Library/Printers and press Enter. Delete any Epson files you see.
• Repeat the "Go to Folder" step for /Library/Printers (without the ~ symbol) and delete the Epson folder inside.
• Empty your Trash.

Restart and Connect the Canon

• Restart your iMac to ensure all cached driver background processes are completely stopped.
• Turn on your Canon printer and go back to System Settings > Printers & Scanners to add it freshly

More info:

Add a printer to your printer list so you can use it on Mac - Apple Support

Print wirelessly from your Mac to your printer - Apple Support