Any idea on auto clean coffee filter mechanism? Do you have any idea on how to design a filter for fine substances left over after the brewing process (e.g. ground coffee or tea) without human intervention? This filter will be used in a vending machine, so the auto cleaning process must be done with rotation, blowing, washing, etc.
Not sure if I understand your question correctly but here's what I thought: Maybe a strip of some sort stretched by two rollers. This would enable the use of a rotating cleaning brush. For the material of the strip I'm not sure.. 

Hope it's of any help..