I have had similar issues with getting the wireless canon printers to communicate with Mac computers. The way to resolve this will be to delete the printer and then readd the printer while it is connected with the USB cable. Add as a USB printer and test print then add as a wireless printer.
Deleting /Adding the Printer to the Printer List (Mac OS X)
Note: After confirming that the cable is connected and the printer is powered on, perform the following:
*Users with Mac OS versions older than Leopard (OS X 10.5.x ) click here .
1. In the Apple menu, open System Preferences.
2. Open Print and Fax.
3. Be sure that the printer to be deleted is highlighted in the Printers section.
4. Click the Minus (-) sign, then click 'OK' on the confirmation message. The printer is deleted.
5. To add the printer, click the Plus (+) sign.
6. Select the printer to add, then click 'Add'.*
* For Canon network printers, the printer must be selected from the Canon IJ Network dropdown in the More Printers tab ( see examples, below )
7. The printer is added.
Deleting /Adding the Printer to the Printer List (Mac OS X ver 10.4.x)
1. Open Applications, and Utilities, and double-click the 'Printer Setup Utility' icon.
Note: Printer Setup Utility has a different name, depending on the Mac OS X version. In versions prior to Mac OS X 10.3.x, double-click the Print Center icon. The above is an image using Mac OS X Ver. 10.3.x. The display in prior versions appears different. The images are an example using the i80 model.
2. Highlight the printer you wish to delete and click 'Delete' .
3. Click 'Add' on the toolbar.
4. Select 'USB' (for network printers, select Canon IJ Network or Canon BJ Network depending on model) from the pop-up menu (10.2x and 10.3x OS's)
5. Select the printer name you are using, and click 'Add' (The printer you are using is added to the Printer List dialog).
Re-adding the printer to the Printer List is complete.