Fans and such can suck up a scrap and then it's sitting in some motor/fan area buzzing. I'd try canned air blasts in the area (keep them short!) and hope you can dislodge it.
If not it usually needs to have a tech tear it down and repair.
my printer is making a low volume buzzing/whirring sound (like some tiny electric motor is running constantly inside it) while on stand-by. what may be the reason?