Electrostatic copying machine

An electrostatic copying machine wherein a carriage is reciprocable between a horizontal copyboard for originals and the flat upper reach of an endless backing belt the outer side of which has a photosensitive surface. The carriage supports at least one exposing device which exposes line images of the original onto the upper side of the upper reach of the belt while the carriage moves from a starting position and the belt is at a standstill. The carriage further supports a corotron which is mounted ahead of the exposing device and charges successive increments of the upper reach, and a developing device which applies toner particles to the electrostatic image on the upper reach. The belt is thereupon moved to transfer the thus obtained powder image onto a paper sheet. The exposing device has several strip-shaped optical imaging components, and the developing device employs a rotary magnetic drum or a set of magnets which are fixedly mounted on the carriage. If the carriage supports several corotrons, several exposing devices and several developing devices, each exposing device contains a differently colored filter so that the powder image is a color image of the original on the copyboard.