Sounds like your print spooler is still crashing when you try to communicate with the printer. That is the only way an error on one printer would effect another, especially when its a different vendor like Cannon.
There is most likely a corrupted driver file or .DLL somewhere on the machine that needs to be cleaned up. Try searching the server for the .dll that you mentioned above ( HPM1210GC.DLL) and manually remove it. Then reinstall a print driver and try again. Chances are the file is on the driver store: C:\Windows\System32\DriverStore\FileRepository.
You also should clean up any unused drivers from the Print Server Properties window. Navigate to Start > Printers and Devices > Highlight a printer > Click the Server Properties button > Drivers tab.
UPD's are designed to be automatic by default. When a new printer is plugged in and previous drivers are not found the UPD will take over and auto install. This causes problems for folks on normal PCs who commonly have to USB plug into several physical printers. It is also why UPDs are mostly for enterprise as they normally take a little more maintenance to setup and configure.
You might also want to try installing the printer on a seperate but similar machine. This might help you isolate a corruption issue further and give you confidence that a reload would resolve the problem. I cant tell for sure if you are describing a real print server or some other general purpose server that you want to install the printers directly on.