From Babbage Technologies:
RenPrinters 3 is a service for Server 2003, Server 2008 and Server 2012 that will rename printers installed by Terminal Service / Remote Desktop clients.
When a Remote Desktop Client logs in to the server their printer is installed on the system in a format similar to the following (depending on your language):
Server 2003 Example: HP LaserJet 5 (from client) in session 10;
Server 2008 Example: HP LaserJet 5 (10);
Server 2008 R2 Example: HP LaserJet 5 (redirected 10);
Server 2012 Example: HP LaserJet 5 (redirected 10).
Every time a client logs in to the Terminal Server the Session number in the printer name will change. This causes a problem in some programs that require the printer name to remain exactly the same. Or you just may need a differrent / shorter naming format than what Windows provides.
The RenPrinters service will rename printers when Terminal Service / Remote Desktop Clients connect to the server.