The purpose of a photocopier is to create copies of graphic or text materials through use of either heat, chemicals, electrostatic or light processes. The photocopier was first invented out of the need to create an alternative to the wet photographic reproduction method used prior.
The first photocopying technique was invented during the early 1950s and used a diffusion-transfer method. This method involves a master copy made on a translucent sheet. The master copy is placed over two layers of negative and positive papers. The three sheets are exposed to light, which creates a copy of the master sheet on the positive paper.