The HKU machines are compact and movable and work with negative pressure. The dusty air is cleaned in the filter unit and the dust is collected with the paper scraps in the dust bin that is placed underneath. The dedusting of the antistatic filter elements happens automatically by using an electro motor vibrator or a jet filter device. The need for dedusting is initialized when the control unit is in stand-by. The emission of clean air occurs directly at the machine. Optionally available is a filling level control for the container as well as a second dust bin.