Suddenly cannot print over WiFi
I had the same issue, had to turn off and on the printer to get it to print every time even if the jobs were only a few minutes apart.   I was not thrilled about changing the 5GHz name as suggested above.

I resolved my issue by going into the Airport Utility on my iphone, go to Edit->Advanced->Add WPS Printer->With pin   

Now my Epson Workforce 845 works as it should.  I assume there is something in the router that treats a printer different than a general client and adding it as I did above solves it...at least it did for me.