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