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 sec