The way the scanner deals with dust is by complaining that there's dust :-) (It doesn't have a special dust error, AFAIK, but it does do some checks that will end up failing if too much dust has accumulated.)
The way to avoid dust accumulation is to keep it covered when it's not being used. That works nicely and is a reasonable thing to do anyway.
The way to avoid dust accumulation is to keep it covered when it's not being used. That works nicely and is a reasonable thing to do anyway.