The act of photocopying: its origins, working and wide-ranging impact

Source: The post is based on the article “The act of photocopying: its origins, working and wide-ranging impact” published in “The Hindu” on 31st October 2023

Why in the News?

Photocopying technology has revolutionized the way we copy, print and distribute textual material.

What is Photocopying?

Photocopying is a process used to duplicate printed or written material by various techniques, primarily involving light. 

The modern and most commonly recognized form of photocopying refers to xerography, which is widely utilized in offices and print centers.

How does Xerography work?

1.Photoconductive Surface: A surface coated with a photoconductive material that allows the flow of electrons when exposed to light but blocks them in darkness.

2.Charging the Surface: The photoconductive surface is negatively charged using a wire with high voltage placed next to it.

3.Paper Illumination: The sheet of paper to be copied is illuminated by a bright light. The areas with print or ink appear darker and don’t reflect light, while unmarked areas reflect light.

4.Reflection on Photoconductive Surface: The reflected light from the paper falls on the photoconductive surface through lenses and mirrors.

5.Electron Dissipation: Light-exposed areas on the surface allow the photoconductive material to become conductive, enabling the dissipation of electrons.

6.Toner Application and Transfer: A powdery substance called toner, positively charged, is applied to the surface. It settles on the negatively charged areas.The surface then transfers the toner pattern to a sheet of paper, attracted by its stronger negative charge.

7.Fusing and Output: The toner, once transferred to the paper, is heated to melt and fuse with the paper.The completed copy exits the machine within seconds.

How did xerography change the world?

Counterfeiting Prevention: Xerography played a role in preventing counterfeiting by incorporating unique markings, like the Orion constellation’s star-like rings, on banknotes. 

– This anti-photocopying feature deterred counterfeiters from duplicating or printing currency notes using xerographic machines.

Impact on Art and Creativity: The spread of copy machines in the 1970s fostered a vibrant arts scene in New York, allowing artists, writers, and musicians to utilize low-cost reproduction methods. 

– It enabled self-publishing of books facilitating the distribution of artistic work beyond galleries and museums.This empowered creative individuals to promote their work independently.

UPSC Syllabus: Science and Technology