Laser Printers

Did you know Laser Printers use Electrostatics to work?

What is a Laser Printer?

It is a printer that uses a laser to react with a selenium drum and ink to provide a desired image. Electrostatics is a electrical charge that remains on the suface of an object and doesn't go away immediately. We use Laser printers in everyday life but do we know that it uses electrostatics as a main component to work?

Electrostatics behind a laser printer and how it works

Before anything is printed the selenium drum is given a positive charge by the charge corona wire attached. Once the charge is given by electrical charge, a laser turns on and starts to draw text or pictures one the drum. SInce the drum is made up of a photoconductive substance it is able to be discharged by light photons provided by the laser. This creates an negative electrostatic image, and positive background. Finally positively charged toner is applied by the developer roller, since positive attracts negative (according to Law of electrostatics) it is attracted on to the drum ready for printing. A sheet of paper rolls in and matches the rolling speed of the drum for precision. Once the paper obtains the toner it passes through heat rollers to be permanently attached to each other. Once printing is done a discharge lamp flashes and the process start all over again.
Lexmark Laser Technology Presentation

Knowledge on electrostatics

We have electrostatics around us all the time, and by understanding how it works on everyday objects that we use, you can see just how fascinating it is! Just imagine what we might come up with next using electrostatics.


Harris, Tom. "How Laser Printers Work" 14 March 2007. <> 13 February 2013.

By: Harry Chan