Printers dropping during RDP Session

I have a pos system that my users access via RDP 6.0 on Windows Server 2003. All works ok when the client logs in, although after being in the session for a while and a print job is sent to the printer the job does not print with a error of the printer in not available. A simple log off and log on the printer is recreated and all works fine. This is ok for some instances but when a patron is standing there waiting on a receipt it can get frustrating. Is there anyway known to avoid having the printers loose it’s connection during the session.