In 1969-1971 American engineer Gary Starkweather, working at a Xerox research facility in Webster, New York, and later at Xerox PARC, invented the laser printer by combining a laser, a xerographic copier, and a Research Character Generator (RGG) that converted digital information to a form readable by a laser. By 1971 or 1973, (sources vary on this point) the first perfected version of Starkweather's invention could print two pages per second at a resolution of 300 dpi. However Xerox did not market a laser printer until 1977 when they offered the Xerox 9700, the first commercially available stand-alone laser printer. Prior to this in 1976 IBM produced the IBM 3800 as a peripheral to computer systems.
Reilly, Milestones in Computer Science and Information Technology, p. 152.