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Electrophotographic Copying and Printing (Xerography)

  1. Dan A. Hays,
  2. Kenneth R. Ossman

Published Online: 15 JUL 2004

DOI: 10.1002/3527600434.eap575.pub2

Encyclopedia of Applied Physics

Encyclopedia of Applied Physics

How to Cite

Hays, D. A. and Ossman, K. R. 2004. Electrophotographic Copying and Printing (Xerography). Encyclopedia of Applied Physics. .

Author Information

  1. Wilson Center for Research and Technology, Xerox Corporation, Rochester, New York, USA

Publication History

  1. Published Online: 15 JUL 2004


In the electrophotographic process for copying and printing documents, the image content controls the amount of light that selectively discharges a uniformly charged photoreceptor material. The electrostatic image is developed with a charged, pigmented powder that is transferred and bonded to paper with heat and pressure. Over the years, a variety of optical devices and systems have been used as electrophotographic technology has evolved to higher levels of performance and image quality. The earlier copiers utilized a light source and lens optical system to project the document image onto the charged photoreceptor. The imagers for copying use either optics with moving components or flash exposure systems. Electrophotographic printers do not use direct optical imaging but use a digital stream from an external source to generate a printed document. These printers were enabled by advances in digital electronics and light sources that exposed the photoreceptor with a scanning laser beam modulated by digital signals. Alternatively, many electrophotographic printers in recent years utilize a Light Emitting Diode (LED) array and optical lens array to imagewise expose the photoreceptor. An electrophotographic printer combined with an image input scanner becomes a digital copier that provides image editing, multiple copies from a single document scan, and digital image processing for high-quality color documents. The advances in imaging devices over the last half century have played an important role in the current achievement of high-quality color electrophotographic documents.


  • electrophotography;
  • copiers;
  • printers;
  • laser raster output scanning;
  • light emitting diode array;
  • optical scanner