Hi.
I believe there would be an ActiveX control that you could spawn hidden (needn't have a parent window) - The RTF control is standard with Windows. I have used it in a windowless environment to do similar printing - but I haven't tried using it from .NET though...
As for the printers for the ASP.NET account - are they network printers or local printers attached to the machine or "local printers" in that they are printing to a local printer port but happen to be on the network?
Cheers!