The advent of new printer technology in the late 1970s and early 1980s brought users the affordable and reliable office printer with replaceable laser toner cartridges. Further improvements and cost reductions introduced the laser printer to a much larger segment of the population – the home user. Since then, the laser printer has proven to be a remarkably dependable and cost efficient tool for home use.
The Basics
The laser printer in all its forms is a superb combination of high-tech engineering and exact manufacturing methods. While no one will be able to construct one in their garage, the principles upon which the new printer technology operates are readily understood.
Information Transfer
Information is sent to a laser printer from a computer or other “smart” enabled device. A portion of this information is then converted by a Raster Image Processor (RIP) into a line of code which indicates whether a toner particle should be placed. This process is repeated until the entire image is completed.
Initial Toner Transfer
The transfer of toner to the page from the laser toner cartridges is accomplished using electricity and the electrical properties of the toner itself. The information encoded by the RIP is electrically transferred to a photoreceptor belt. This belt contains a charge at each location where a particle of toner will adhere. As the photoreceptor belt turns, all parts of it are exposed to the toner particles which are attracted to the appropriate spaces.
Secondary Transfer
Once the toner is on the photoreceptor belt, it travels past a second belt that holds the final printing medium, usually being paper. The toner is then transferred onto the paper via pressure or another electrical charge emanating from the opposite side of the paper.
Fusing and Cleaning
The next step involves heating or “fusing” the toner so that it remains permanently affixed to the paper. This is an important step as the toner will simply wipe off if not properly fused. As almost any office worker can tell, unfused toner is incredibly messy and can ruin clothes in an instant. It is the body heat of the user that sets the toner and makes it almost impossible to remove. The last step eliminates this problem by cleaning the paper of any unfused toner with a final electrical charge.
Color Copiers
Color copiers may seem significantly more complicated than simple black and white models, but they operate on the very same principles. However, four toner cartridges, or one with four separate compartments, are needed to accomplish the job. These four colors, cyan, magenta, yellow and black, are simply placed one on top of each other to obtain any of the colors of the rainbow.
