Transfer unit for xerographic printing machine with constant ventilating interior

摘要

A transfer unit for a xerographic printing machine including at least two rollers and an endless belt supported by the rollers. A frame member supports the rollers. A photoreceptor is disposed adjacent to the endless belt, and a charging means is disposed opposite to the photoreceptor so that the endless belt is locate between the charging means and the photoreceptor. Pressure in the space within the transfer unit, which is surrounded by the endless belt and the frame member and contains the endless belt charging means disposed therein, is slightly higher than atmosphere pressure outside the transfer unit.