Network Printing

I work at a school, when a staff member is adding a printer, they go to start -> Printers and Faxes -> Add a printer -> A network printer…( generally have them ) -> Connect to this printer, next, from this point it takes a good 3-4 minutes while stating searching for printers…evetually it comes up with shared printers. Is there a reason that it takes so long to generate that list?