Windows 7/SP1 with 2 NIC

Hi – We have two NIC cards on windows 7 SP1. 1st NIC connects to the office network and the other NIC connects to Xerox scanner directly via a local switch/HUB. We are able to ping the Xerox scanner from the PC, and we are also able to ping devices on the office network.  The NIC's are on completely separate networks.
However, when we run the scanning application and want the PC to use the NIC connected to the Xerox scanner it fails. The NIC on the office network has all the IP setting/S.Mask & Default Gateway. The 2nd NIC connected to Xerox only has the IP and S.Mask.
What can we do, so that when we run the scanning app on the PC that the PC uses the NIC connected to the Xerox scanner as opposed to the office network. At present we initate the scan from the PC the app times-out, because it cannot reach Xerox….I guess it defaults to using the Office NIC. How can we stop this…..can we create a Static route or use RIP etc…suggestions welcome.
Regards
ADAM