If you are in a canon printer offline  state then you should know the reasons behind it so that you know how to fix it. If you won’t know the reasons then it is quite obvious that you will have a hard time in resolving the issue.
·        If the default printer settings are incorrect then it could be the reason why your printer goes offline. You need to ensure that the canon printer has been set as default
·        You can also check if ‘Use printer offline’ has been enabled or not. If it has been enabled then deactivate it and try again
·        If there is a technical issue with the printer spooler then this will also show the offline status of the printer