This revolutionary invention was based on an inkjet-less machine, able to print text, graphics and images by repeatedly passing a soft laser beam on paper.
What Is a Laser Print?
Invented in the 1970s, a laser printer is a digital machine that prints high-quality text and graphics and moderate-quality images thanks to an electrostatic process repeatedly passing a laser beam on paper. The electrostatic process is possible because of a negatively charged cylinder, called “drum“, which transfers the image on the paper. This process is quite different from inkjet printing: the laser printer makes use of toners. Like digital photocopiers, this is a xerographic process, but in this case the print is produced by reflecting light off an existing document.
While in the 1960s the Xerox Corporation was a leader in the photocopier market, Gary Starkweather, Xerox’s product developer, had the idea of using a laser beam to “draw” an image directly onto the copier drum. A few years later this idea became reality in the Palo Alto Research Center, when Starkweather adapted a Xerox 7000 in a Scanned Laser Output Terminal, or SLOT. This project gave birth to the first commercial laser printer for computer output, the Xerox 1200. But little by little other competitors broke the market: after the success of the IBM 3800, the Japanese camera and optics company Canon developed a low-cost desktop laser printer (the Canon LBP-10), followed by HP and Apple. Today this system invented by Xerox is widely diffuse, also considering its entry-level affordable price.
Laser Printing Process
The whole process is focused around a laser beam, which projects an image of the page to be printed onto an electrically charged cylindrical drum Thanks to the photoconductivity, charged electrons fall away from the areas exposed to light, and a powdered ink (toner) particles are electrostatically attracted to the charged areas of the drum that have not been laser-beamed. In this way, the drum is able to transfer the image by direct contact onto paper, which passed through the machine. Lastly, the finisher uses heat to instantly fuse the toner that represents the image onto the paper, and the print is ready.
This Technology Today
Nowadays the cost of laser printers has fallen markedly: the HP LaserJet, for example, was sold for $3500 but was very distant from the performance of a modern laser printer. By the 1990s, the market provided different printing technology, and laser printers become inexpensive enough for home office use. Fastest modern models can print 12,000 pages per hour. These high-speed laser printers are used for mass mailings of personalized documents, such as credit card or utility bills, and are even competing with lithography in some commercial applications. Even if printing technology has taken giant steps today and we have 3D and digital printing, laser printers are still very often used.