It is probably hard to imagine a person in today's society who has never heard of computers and peripheral technology for them. Today, these devices have become almost indispensable in the lives of modern consumers. One of the auxiliary elements for quick and convenient operation are printers. As a rule, similar equipment can be found in almost every office, but for home use its acquisition is much less common. Nevertheless, many people know about the existence of these devices, but not everyone understands the principles of the printer.
There are two main types of printing devices - inkjet and laser. The principles of the laser printer, of course, are not similar to the principle of the inkjet printer, since their design is different. Today, consumers prefer to choose models with laser printing, arguing that higher quality. Of course, such models have a cost much higher, but if there is a constant need for high-quality images, then the price fades into the background.
So, what are the principles of laser printer? First of all, it should be noted that they are based on the design features of the device. The required image is printed using electrophotographic technology. It lies in the fact that each point on the sheet is located in a specific place on the page by changing the charge of electrons on a special film. As a rule, it consists of a semiconductor capable of changing the electrical conductivity under the influence of radiation. The same technology is commonly used in photocopiers.
Whatever the principles of operation of a laser printer, nothing would have happened without a rotating drum, which is the main structural element of the entire device, because it is with its help that the image is transferred to a sheet of paper. It is a kind of cylinder made of metal, which is covered with that very special semiconductor film. First of all, the surface of this drum is charged with positive or negative ions.
Further, with the help of a laser, the thinnest light beam is created, which moves along the drum, reflected from several lenses and mirrors. The spot light incident on the surface of the drum discharges it at the point of contact. The laser, as a rule, is controlled by a microcontroller, turning it on and off if necessary. Usually, image formation on the drum occurs line by line. At the end of compiling the picture in one line, a special engine, also called a stepper motor, slightly rotates the drum so that the possibility of further laser operation appears. Thus, an image consisting of charged points appears on the surface of the cylinder. These points alternate with discharged, located in those places where there should be no image.
At the next stage, the principles of the laser printer involve the direct application of the image on a sheet of paper. Before this, toner having an opposite charge adheres to charged places on the surface of the drum. At the same time, the drum rotates slowly so that the paint is evenly distributed. Continuing to rotate, the cylinder with the toner applied on it is in contact with the surface of the paper, as a result of which the ink is transferred to the sheet.
Next, the paper should pass between the two shafts. Typically, the upper shaft has a high temperature, and the lower shaft presses the sheet against the upper. Thus, the ink particles are heated and fixed on the surface of the paper. Lastly, the drum is cleaned of residual toner with a special device, and then a charge is again applied to its entire surface.