Over the years, I have seen numerous issues with a Canon imageCLASS Printer. Some are simple to troubleshoot while others are not. Let us go over what I have encountered.
One issue that I see frequently is the end-user having trouble to scan with a Canon imageCLASS MF4450 that is hooked up to their workstation, so I wrote an article to cover it so that they and those searching the Internet can refer to it when needed.
Now, for some reason, the end-users expect to be able to scan to their workstations from a Canon imageCLASS Printer the is set up in a networking environment. An Epson WorkForce is what they need or a Ricoh or HP which can scan to an email address.
If the Canon imageCLASS Printer suddenly shows offline in the Devices and Printer area, check to see if the USB is disconnected or damaged. If you reconnect the cable after confirming the cable is undamaged and working fine on another computer, you will need to save your programs on the troubled computer and then power down the printer and computer for 30 seconds. Once the time is elapsed, power on both the computer and printer. The printer should now show a ready status with the USB cable connected.