What could be causing this?
Since the print is already in progress, I would have to suspect the driver.... so I have to ask whether you downloaded the W7 driver from Canon and was it a match for your 32 or 64 bit Windows 7?
Fred
Fred meant "W7 driver from
Epson" but otherwise, I think this is the best advice. 90% of problems come from not having the Windows 7 specific driver installed. Also realize that after moving to Windows 7, your Qimage saved jobs and saved print settings will not be compatible with the ones you saved/used in XP/Vista because Windows 7 driver settings are not compatible with XP/Vista driver settings. You may need to use "Help", "Reset printer settings" in Qimage and after that, be sure not to load any prior saved jobs/setups unless they were saved from Windows 7.
Mike