In my limited experience (one 30-user network), we've done
this:
0) (Optional) Do everything at a quiet time (night/weekend);
1) Set up and test all your printers on the desired server,
with the latest drivers;
2) Unshare each shared printer on your DC;
3) Share and test each printer on the new server;
4) Deploy each printer as necessary throughout the network.
Either delete the old ones and add new, or - if the drivers
are the same - add and change ports as necessary. I've
find it most convenient to delete the old printers and use
IE to specify the print server and find the new printers.
Hope this helps.