How Do Laser Printers Work?

You might wonder how laser printers work. Every time you click the Print button on your computer, you are not waving a magic wand like in a Harry Potter movie. Far from it! Complex processes are at play, and they involve lasers, mirrors, carbon, static electricity, and heat. Read more to understand how laser printers work.

How Laser Printers Work: A Short Explanation

The laser inside the printer projects the image or text on a specially coated metal cylinder called a drum, giving it a static charge. When the drum rolls, the carbon toner particles with opposite static charge attract to the drum and transfer to the paper that’s passing through, which is then heated to melt the toner on the page.

What Is A Laser Printer?

Many different types of printers are available on the market today, and each uses different technologies to achieve a similar printed page as a result. The laser printer was the first to be invented. It was created in 1969 by Gary Starkweather who worked in the Xerox product development team. His idea was to use lasers to print an image on a copier drum, which then would be transferred onto paper. Hence the name “laser printer.”

So why choose a laser printer over another type of printer like an inkjet?

Well, laser printers are very efficient and cost-effective when you need to print high volumes in a short interval. Toner cartridges can print thousands, sometimes tens of thousands of pages, which is something inkjet printers cannot do. However, as the inkjet technology advanced, many exceptions to the rule are now available.

How Laser Printers Work: Full Technical Explanation

There are many moving parts and components inside a laser printer. Each part has a key role to play and they work together to produce your final document or image. The key parts of the printer include the toner cartridges, the image drum (also called drum or photoconductor), the transfer roller or belt, the fuser, the laser, and the mirrors.

Step by Step

As soon as you click “Print” on your computer, tablet or mobile device, the information is sent to the printer memory, where the data is stored.
The printer starts to warm up. This is the point where you usually hear a noise as the corona wire gets hot and ready to send its positive static charge to the drum.
When the drum (coated metal cylinder) begins to roll, it receives a positive charge across its entire surface. Some printers contain 4 drums, one for each color—cyan, magenta, yellow, and black.
The laser activates and beams against a series of mirrors to reflect the surface of the drum(s) printing the shape of your print using an opposite negative electrical charge.
The toner cartridge and the hopper, placed next to the drum(s), slowly release toner positively charged carbon toner particles on the drum as it rolls, and the toner is attracted to any areas negatively charged, leaving positively charged areas of the drum intact.
The transfer belt rolls the paper through the printer by giving it a positive charge, and as it passes under the drum, the negatively charged toner is attracted to the page in the shape of your print.
The toner is then melted on the paper by hot rollers collectively called the fuser unit and, there you go, your page is printed!