On a network of any size, you probably will concentrate your printer installations at a few servers. A computer acting as a print server can act as a file server or database server at the same time. No special hardware requirements exist for print servers except that they have appropriate printers (output ports) for parallel or serial print devices.
Managing a large number of printers or many large documents requires an adequate amount of memory. Disk space requirements are minimal except in cases where large or numerous documents are likely to accumulate.
When you use Advanced Server for both file and print sharing, file operations have first priority. Printing transactions never slow access to files. Moreover, file operations have negligible impact on printers that are attached directly to the server; parallel and serial ports are always the greater bottlenecks. A dedicated print server may be desirable if a server is required to manage many frequently-used printers.
The decision to combine print and file servers may depend on security concerns. While printers always should be available to those persons using them, you may want to restrict physical access to file servers by keeping them in secured rooms.