Photocopier, Copier

Today, photocopiers usually work on the Xerox or dry principle. Wet methods are frequently used for large architectural drawings but in the past all copiers used wet methods.

In the Xerox method a light source illuminates the original and the reflected image is focussed onto a negatively charged selenium drum. Where the light (from the white paper) hits the drum the charge is dissapated but the drum remains charged where the light doesn't strike the drum (corresponding to the black type). Toner (a black powder) is attracted to the charged areas so that there is a pattern on the drum corresponding to the black areas on the original. The drum rotates and comes close to a sheet of paper. A positively charged wire below the paper attracts the negatively charged toner onto the paper. The paper then passes below a heater that fuses the toner onto the paper to give a permanent image. Coloured toners may also be used.

Feel free to copy the graphic and text without restriction. Created by Mijami World.

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