electrophotographic images

Electrophotographic Process

Electrostatic charges are used to create a charged light image on the drum. The toner is attracted to the drum and then to the paper.

Laser and LED Printers

The difference between a laser and LED printer is how the light image is "painted" onto the drum. The laser uses a single light source that is directed by moving mirrors. The LED printer uses an array of hundreds of LEDs that are selectively beamed onto the drum. In a real laser printer, there are many more lenses and parts than in this simple diagram.

The Model A

The first electrophotographic copier was sold in 1950. Although manually operated, it provided the experience and revenue to develop automatic xerographic machines. In 1959, Xerox's 914 copier became a huge success. (Image courtesy of Xerox Corporation.)

Chester Carlson

In this 1965 photo, Carlson enacts his 1938 experiment in which he wrote "10-22-38 ASTORIA" with india ink on a glass slide. The room was darkened and a zinc plate, covered with sulphur, was rubbed vigorously with a handkerchief to apply an electrostatic charge. He put the slide on the plate, exposed it to light for a few seconds, removed the slide and sprinkled lycopodium powder on the plate. He gently blew off the loose powder and what remained was the first electrophotographic copy. After Xerox became very successful, Carlson was showered with honors and wealth. In 1968, he died of a stroke on a street in New York. (Image courtesy of Xerox Corporation.)

More electrophotographic images

Learn more about electrophotographic