The first xerographic machine came onto the market in 1949, but it was slow, dirty and hard to use. Not until 1959 did Xerox introduce an office copier, the 914, which became the basis for the current multibillion-dollar industry. CHIP HOLT is vice president of the Joseph C. Wilson Center for Research and Technology at Xerox Corporation. The electrostatic charge on the belt fades in areas receiving light from the projected image. A sheet of copy paper approaching the belt is also given a static charge sufficiently strong to draw the image pattern in the toner away from the belt.
Rollers then apply heat and pressure to fuse the toner image into place.
For color copying, a multistep process is used, which scans the image through color filters and then applies separate toners for magenta, cyan, yellow and black.