In this article he mentions many troubleshooting techniques. He also recommends using a secondary IP Address and assigning it to iPrint.
"It is probably a good idea to get an IP address assigned to your iPrint service, since you can move it via a cluster, or even in case of a server failure. If all your users install printers that point at a service address (like iprint.yournetwork.com) instead of a server address (serverA.yournetwork.com), when you move it around, your clients will not need to reinstall the printer. If the IP of the service changes, then the printers look like new printers."
You can assign it as a Secondary IP address. At the console type:
add secondary ipaddress 10.0.0.5