Abstract: A high speed color reproduction machine comprised of four separate xerographic type processing units, one for each of the primary colors plus black. The multiple processing units are arranged in close nested relationship to one another with the image transfer stations thereof in close succession along the path of movement of the copy substrate material. A combination air flotation type and vacuum based belt transport system is employed to bring copy substrate material from a supply source into transfer relation with the successive processing units. Exposure of the processing unit's photoreceptors is simultaneous. A precise dimensional relationship between photoreceptor length and spacing for each processing unit assures registration of the color images produced with one another. Following transfer of the last color image, the image bearing copy material is brought to a fuser where the image is fixed. The finished copy is thereafter discharged, or returned for a second duplex pass.