The Canon Pixma drivers for Windows don't talk to the Canon drivers for Mac. I've had this issue setting up cross platform printing at work and finally gave up. Windows will "see" the printer, but nothing you send will ever come out. The problem has nothing to do with Parallels, since it happens with network shares also.
A Windows network share of a Canon Pixma will print from a windows client, but not a mac client. Similarly, a Mac share of a Canon Pixma will print from a mac client, but not a windows client. Officially, Canon states they do not support network shares of the Pixma series printer, even though it does generally work when not in a cross-platform environment.
I've talked to Canon tech support about a related issue, and their official response was "Canon has found that network/print server/print sharing environments do not function with 100% compliance to Canon compatibility standards."
My suggestion is to just go to your Devices / USB menu of your VM and connect the printer directly to Windows when you need to print. That's what I do with my Canon.
Note: The Canon drivers for OSX Tiger DO work cross platform. It is just the Leopard ones that don't.
Last edited: Dec 31, 2008