I've been experiencing this issue a lot lately. First off, I have one of those wireless routers with a 2 GHz and a 5 GHz network. I'm not sure if that's what's causing this problem, but I have a feeling it has something to do with that.
I added my wireless printer to my Mac. All works fine, I print something, and then I don't need to print anything for a while.
The next time I need to print something, my printer can suddenly no longer be found on the network. The Mac remembers the printer, but it can't find it. I switch between both the 2 GHz and 5 GHz networks, same result: no printers found. I can't even add the printer again without having to disconnect the printer itself from the WiFi and have it rejoin the network. Since the printer itself is not compatible with 5 GHz networks, it always defaults to the 2 GHz network.
Needless to say, this issue is extremely irritating, and I don't want to keep having to re-add the printer every time I need to print something.
I have had this issue with 2 different printers now, both completely separate brands (first Epson, now HP). I didn't have this issue before I started having two separate wireless networks on my router, which is what makes me think that is what's causing the problem.
Has anyone else experienced this issue or know of a permanent solution?