How Laser Printers Work

Laser printers are the most popular types of printers currently being used all over the world in a host of widely different applications. Laser printers are popular because they are extremely efficient and cost effective, they can print a variety of images and documents at a high level of quality. While we all appreciate the quiet efficiency of a good laser printer, how many of us actually know how laser printers work?       

The basic concept behind a laser printer is actually quite simple. The main component inside the laser printer is what is known as a drum, or more accurately an electrically charged drum. This electrically charged drum is then exposed to a laser, also within the printer housing. This exposure to the laser then creates areas that are positively charged and other areas that are negatively charged.  

The next phase in the process involves the toner which is a form of powdered ink. This toner is positively charged and thus sticks to the areas on the drum that are negatively charged. The ink is then heated until it becomes a sticky liquid paste. The printing is then applied to paper fed into the laser printer. The image is printed from the drum onto the paper.   

The toner which is hot then cools, this cooling process is how the image or toner is bonded to the paper. The way that colour laser printers work is by applying four different colours of toner, namely black, magenta, yellow and cyan from four separate toner cartridges stored inside the laser printer. At first the early versions of laser printers required a number of separate passes by the paper over the drum. This was necessary to get all of the toner onto the paer and create a proper image.

As laser printer technology evolved laser printers became much better at getting the toner off the drum and onto the paper, todays laser printers only require a single pass in order to make a good print. Generally laser printers require a bit of time to warm up before they can print, this is so the toner is warm enough to stick. The newest laser printers only require a few seconds before they are ready; the drawback to these is that they consume far more electricity in the process.