Windows 7 network brother printer shows offline when it is online and working

I have a brother duplex network printer. From my main machine which is always  on I can see the printer - it says it is ready and I can print to it. All is well. But I also have a windows 7 laptop.

Now when the printer was re-installed it could see it for a couple a days. The overnight the laptop could see the printer as offline.
Now many of the fixes on the Net tell be about firewalls - no change here, changed IP addresses - not changed switching the printer to offline mode - ok now this works up to a point but if the printer is turned off.

So for the Solution
Re-install the printer. I had to on mine because it would not let me do this until I had.
Start -> Devices and Printers -> Double click on the new printer -> Customise Printer -> Ports -> Configure Port
SNMP Status Enabled Uncheck  then OK

The laptop occasionally sends a message to the printer asking it if it is there, via SNMP. If the laptop does not get a reply it assumes the printer is offline. Some how when the windows 7 machine goes off it loses the SNMP connection with the printer and can't find it again.