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How Do Photocopiers Work?

28 Mar
2017

Picture the scene: it’s Monday morning and you’re yawning over the photocopier, making various copies of a document for your afternoon meeting. It’s a love hate relationship; sometimes the cursed machine may jam, or not print out, and occasionally it may give you cause to use some creative swearing, yet just imagine where you’d be without it. 

 

Despite its many faults, the humble photocopier really is the work horse of the office and generally doesn’t get enough credit; how much more difficult would your life be if you had to copy all those documents out by hand! But have you ever wondered how this much overlooked office staple actually works? Well, we have, so read on to find out.

 

The Early Days Of The Photocopier

 

When you actually stop and think about it, the fact that you can create exact copies of anything you need in seconds, with just the push of the button, is pretty amazing, but where did it all start?

 

 

Well the first photocopier was invented by a man named Chester Carlson who lived in New York in the 1930s. During the Great Depression, Chester, who had a degree in physics, worked at a battery factory during the day whilst studying law at night, before finally finding a job as a patents’ lawyer. It was within this later role that he had the inspirational idea of creating a way of copying files more efficiently, as he found that part of his job to be the most tedious. Using the knowledge he’d gained from experiments in the field of photoconductivity, Chester discovered that when light hits the surface of certain metals or chemicals, its flow of electrons (or its conductivity) increases.

 

Chester filed his patent for the first photocopier in 1937 and, initially, many large companies passed up on the chance to go into business with him. At the time, they didn’t think the need to copy large volumes of documents in one go was something that would be widely desired, although we’ll bet those same companies were kicking themselves once the photocopier took off and became the must-have piece of technology in every modern office!

 

Originally, these early photocopiers were all analogue, however, as with everything else, they eventually evolved into the digital machines you’ll most commonly find in your office today. So, let’s take a look at how both types of copier work.

 

The Science Behind the First Analogue Photocopiers

 

Now photocopiers may look complicated, but they are actually based on two areas of science that you should probably all remember from your classroom days. Ever rubbed a balloon against yourself at a party for a few seconds so you can stick it to yourself, or maybe gotten a shock when walking across a carpeted room? That’s static electricity. When used within a photocopier, the electrostatic charge becomes a sort of scientific glue. So, the page you want to copy is placed on a sheet of glass and the light shining through it projects the image onto a positively charged belt; this is known as photoconductivity. This belt in turn is coated in a material that conducts electricity when light falls on it, so that when the image of the page is projected onto it, the areas of the belt that are lit lose their electrostatic charge.

 

 

Now the toner (that stuff you’re always having to replace but never know why) is not an ink but a black powder that becomes negatively charged, and is then attracted to the positively charged areas of the belt. As the paper is pulled through and over the belt, it transfers this copied image onto the sheet, and is then heated up to enable the toner to stick and the image to become fixed. It’s also why the paper coming out of the photocopier always felt so warm and toasty.

 

Digital Photocopiers

 

Nevertheless, most photocopiers these days are now digital; in fact, you’re unlikely to find an analogue photocopier anywhere these days, other than in a museum.

 

The first digital copier was invented in 1981 by Ricoh and was quickly followed by Canon. Unlike the old analogue machines, these copiers scan the document using an image sensor chip, creating a digital image of the document, which is then printed onto the paper the same way as an inkjet or laser printer would print it. The image is used to drive a laser and rotating mirror, which deposits an electrically charged version of the original image onto the photoconducting drum, which in turn picks up minute toner particles, thus creating a copy of the image on the drum. Once the image has been created, the paper then feeds through and the image from the drum is printed onto the sheet, before going through heated rollers to fix the image onto the paper. Simples!

 

 

Whilst it’s true that digital copiers create cleaner, higher resolution copies of the original than analogue copiers do, one downside of a digital copier is that it will store the images scanned into it on an internal hard drive, which can pose a security risk if the files being printed are of a confidential nature, as they could be accessed by other people even after they have been deleted.

 

Get In Touch

 

So there you have it, the next time you are impatiently waiting in the queue for the photocopier machine, you can wow your colleagues with your scientific knowledge about how the copier magically transfers your original document onto as many new sheets of paper as you desire. Though not too many, think of the trees!

 

If you’d like to find out more about how any of your office devices actually work, or if you’d like North West Digital to come out and fix or service one of your devices, then please do get in touch with us.

 

You can contact us in any of the usual ways; by email at info@nwdigital.co.uk, by phone on 0161 477 8950 or by completing the Contact Form on the website for one of us to get back to you ASAP.

Rachel Weinhold
author

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