Electrophotographic printing machine providing both monochrome and color images

摘要

A copying machine as an example of electrophotographic printing machines is composed of a main body which permits both black-and-white copying and full color copying, and a reverse and retransport unit provided under the main body, for reversing and retransporting a sheet after being copied on one surface thereof to the main body. The main body has a fixing means including upper and lower fixing portions formed between three heat rollers. The lower fixing portion placed closer to the reverse and retransport unit is associated with the black-and-white copying, and the upper fixing portion is associated with the full color copying. Upper and lower discharge transport paths for discharging the sheet out of the device are provided so as to respectively extend from the upper and lower fixing portions. Further, a retransport path is provided so as to extend from the lower fixing portion. Since the above three paths are provided without having any crossing point, the structure of the paths is simplified. Furthermore, when carrying out a black-and-white copying on one surface of the sheet and a color copying on the other surface, the black-and-white copying is carried out first, thereby eliminating the problem of the sheet being stuck in the device.