How Does a Photocopier Work?
A photocopier uses electrostatic charge to produce a copy. The page you want to be copied is placed onto a sheet of glass.
At the heart of a common plain-paper copier is a plate of selenium. This is an element which holds an electric charge in the dark, but loses it in the light. First, the plate is charged with electricity. An image of your document is then focused onto the plate.
Wherever the dark parts of the image fall, the plate keeps its charge. The image is made visible by dusting the plate with toner (ink) powder that sticks to the charged image. The image is then transferred to the copy paper.
The paper is heated to fuse the powder and forms a permanent print. This is called fixing the image. When you use a photocopier you can feel that the copier paper is still warm.