Hi,
1. Do you get any receive any error message?
2. Have you made any recent changes to the computer prior to the issue?
3. Was it working fine before?
Method 1:
Connect the printer wirelessly and run the printer troubleshooter.
Open the Printer troubleshooter
http://windows.microsoft.com/en-US/windows7/Open-the-Printer-troubleshooter
Method 2:
Refer to the following link:
Printer problems in Windows
http://windows.microsoft.com/en-US/windows/help/printer-problems-in-windows
If the issue still persists, I would suggest you to contact Canon support for further help.
Hope this helps.