Electrostatic machine incorporating toner scavenging chamber.

摘要

An electrostatic machine has a moving photosensitive drum (10) on which electrostatic images are formed and developed by means of toner powder. The developed images are transferred to copy paper and the drum cleaned for re-use. The drum (10) carries with it a boundary layer of air in which unwanted loose toner particles are entrained. A scavenging chamber has a mouth to draw air from the boundary layer into a vacuum chamber (47). The mouth has a lip (46) forming with the drum (10) a venturi passage (48) through which the air flows to expand into the scavenging chamber. A further knife edge lip (49) peels the boundary layer air from the drum.