Cannot connect to scanner over network.

I have a Canon MG2100 printer/scanner connected to a Windows 7 PC and shared over a wireless network.

I have set up the printer/scanner on my Mac, and all drivers are installed. When I connect to the Printer/scanner via the USB cable, the device works perfectly and is recognised in Image Capture/Preview and in the Printer/Scanner Preferences pane I have a button for Print and one for Scan listed above the device.

However, whilst I can connect to the device and print over the wireless network, my machine is unable to recognise it as a scanner. In Image Capture no devices are listed, in Preview the "import from scanner" option is greyed out, and in the Printer/Scanner Preferences pane, the listing for the networked device has only a Print tab.

Has anyone faced this difficulty before and knows how to overcome it? I don't object too strongly to having to plug in a USB cord on the rare occasions that I have to scan something, but now I'm just annoyed that I can't get it to work and would like to sort it just to satisfy myself that it can be done!