Laserdrucker

A laser printer is one of the impact-free printers, the non-impact printers.
It is also used for the production of printouts on foil or paper using laser exposure and toner particle printing processes. This means that a laser printer prints onto paper with a resolution of 600 to 1200 dpi using a laser beam and high printing speeds. A laser printer has a built-in light-sensitive drum called the imaging drum.
It consists of a semiconductor material and for this reason reacts to the irradiation with light.
First, the drum is negatively electrically charged in order to be exposed afterwards.
In the past, a laser was used for this, which was guided over the drum with the help of a polygon mirror.
The charge is neutralized in the exposed areas. A charge image is created.
A dot pattern of the files to be printed is written onto the drum, so the charge image becomes more and more similar to the printed image.
The imaging drum moves past a roller that has a thin layer of negatively charged toner particles on it. These react with the negatively charged spots on the image drum and are repelled, so they can only stick to the neutral spots. This is how the toner image is created. The paper to be printed is positively charged and is fed past the toner-loaded image drum.
The opposite polarity of the charge causes the toner to be drawn onto the paper. The toner image is now on the paper, but still needs to be fixed so that it doesn`t smudge. This usually happens with heat and pressure. This means that the paper is pulled onto a hot roller which presses the toner onto the paper and heats it up at the same time.
Today, most laser printers work with LEDs, i.e. light-emitting diodes. These are arranged in a row and replaces the printer line. Each LED represented a pixel of this line.
The advantage of this is that you use fewer mechanical parts for the construction and can therefore also make it cheaper.