Originally Posted by
mudski
What O/s are you using and what brand and model printer is it? I'm guessing your printer, it has a dynamic IP address which takes it offline when it cycles through its IP addresses, and is not being seen by the network. You will need to get into the settings of the printer and manually set the IP address of the printer. How? depending on the printer but usually there will be a settings tab and find an option that may say sometihng like "choose or setup up network". It will be in there somewhere.
There is an option somewhere in your setting to print off the network settings, which will show what IP address is currently being used. Then use that as your permanent IP address when you go into the network settings.