Abstract: An electrostatographic printer is described for forming an image onto a moving web or sheet. The printer includes a number of toner image-producing electrostatographic stations having rotatable drums onto which a toner image can be formed. A development station forms a toner image on the drums. Drive rollers convey the web past the image-producing stations. Corona discharge devices transfer the toner image on the drum surface onto the moving web. The printer also has an air-conditioning device which has filters for removing dust and ozone from air leaving the environment of the image-producing station, a heat exchanger and a humidifier for adjusting the temperature and humidity of air leaving the environment of the image-producing station, and an inlet manifold for introducing a stream of the conditioned clean air into the environment of the image-producing stations.