When it is judged that the integral value exceeds a predetermined maximum value, the controller causes a display device to display {HEAD ~ the necessity} of emptying {TAIL ~ the container} 
of emptying
When it is judged that the integral value exceeds a predetermined maximum value , the controller causes a display device to display { HEAD ~ the necessity } of emptying { TAIL ~ the container }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL