you can connect a printer to a network two different ways
cheap - enable printer sharing on your networked computer that has a printer attached to it, downside is you have to have this computer turned on to use the printer from anywhere else on the network.
a little more money - get a printer server (essentially a miniature computer, with memory). the printer server attaches to the network just like a computer would. you connect it to the router or switch that you have througha cat5 connection. the printer server either plugs into the printer in a slot (if your printer has this), or else it is a smallish box that has a parallel port out connector which goes to your printer. some servers can accomodate multiple printers at the same time.
the printer server can accept printing from any computer on the network without any other computer being involved.
you do not "need" a printer server