Morning, thanks for your reply. It is completely random when the printer "disappears". There is no duplicate IP as I have a reseveration for it included in my DHCP service.
I have engaged HP, they updated the firmware but that didn't solve the problem. I now have a local tech assigned and he is waiting for parts then I expect he'll be swapping out the board or maybe even the entire device.
I will post the results once they are known.