Automatic printer switch off

I wanted my printer to switch off automatically after printer job done
and not caring about fans still running. So I decided to create this thing.

The Power of my printer is derived from an ATX Power adapter and the Printer On switch basically shortcuts the green wire of the ATX supply to ground.

When my printer jobs finishes, my printer does a homing of X and Y, so wenn X axis reaches home position, this could tigger a limit switch.(switch off)

So the basic Idea is to create a second "switched" On switch.
This is an electrical path from ground to 2nd onSwitch - to extra limit switch - and finally to to green wire.

So when you successfully started your print job, you would supply the printer from the 2nd on switch.

Actually a simple limit switch is not sufficient: When homing triggers the limit switch it will disconnect the power, but when looses force it might snap back , providing power again to the printer. So the printer will just make a reset, but not sw