ABSTRACT
From this time the growth of Xerox was explosive, reaching $1 billion in sales by 1968. Although Carlson had used sulfur as the first photoactive material, selenium metal was found to be much more practical, and this was the basis for Xerox’s technology in the 1960s. The first commercial “ dry inks’’ used with selenium were based on styrene methacrylate copolymers and had a negative electrical charge.
