Xerox’s first true full-color copier, from concept to implementation and build, was introduced in 1973. The only other competitor was 3M’s, which was introduced in 1969.
Xerox had purchased one of these 3M copiers for our engineering lab for study. The physical size of the copier was large, bulky and quite long! In my opinion, it was not a true color copier in the sense that it used three large rolls of sensitized paper: yellow, cyan and magenta (an electrostatic process.) It produced one color copy per minute.
The Xerox color copier program had an internal product code name Epic-6500. When introduced in 1973, it was named the 6500 Color Copier. It made four color copies per minute on plain paper. It used some of the parts from the first fully automatic black-and-white copier in the world, the 914 Copier, launched by the Haloid Xerox Corp. in 1959. The Epic frames and covers were all made of sheet metal in house. read more here