You want the IP address of the printer to be consistent. There's a few ways to do this:
1) manually enter the network info (address, gateway, subnet) into a printer via control panel (or web interface, if it gets one via DHCP & you can connect)
2) reserve an address in DHCP for it. You'll need the printer's MAC address, sometimes you can get that from a status printout. This is better than choice 1 because now the router won't assign the manual address to another device.