serial exception disconnected 4.5 into 5 hour prnt\

what is this??

Print started at: 08:49:35
ok p:22.20 i:1.08 d:114.00 c:0.13
Can’t read from printer (disconnected?) (SerialException): call to ClearCommError failed
Can’t write to printer (disconnected?) (SerialException): WriteFile failed ([Error 31] A device attached to the system is not functioning.)

Make sure you have sleep or power saving features turned off on your computer.