For over 20 years, a laser printer has been an integral part of office life - a place where fast, large-scale daily work is needed. The external simplicity of the design hides mechanisms and complex technological units under the body. Laser cartridges can be attributed to the main component of devices of this design, in which toner — a coloring powder — is used to obtain images. To better understand how a laser printer works, you must first disassemble the components of which it consists and understand their purpose.
How the laser printer cartridge works
The body of the laser printing device is two fastened main units: on top is the waste toner bottle, and on the bottom is a paint container.
The upper part includes:
- photowall - a hollow cylinder with a surface of photoconductive material;
- a metal shaft providing a negative charge to the photocell;
- blade for cleaning (squeegee);
- waste toner bottle.
The toner compartment, which is the lower part, includes:
- Magnetic type shaft (developer). It consists of a shell, a core having a positive charge. It attracts particles of the coloring powder, after exposure to a certain voltage. Charged negatively.
- Dosing blade (doctor). To ensure uniform distribution of paint on the shaft.
- Capacity for primary toner.
- Protective seal. Does not allow powder to wake up during transportation.
The principle of laser printing
The principle of laser printing is as follows. The basis of the device is a photoconductive shaft. It allows you to transfer a picture to a medium. This shaft, coated with a photosensitive layer, is a hollow cylinder with a charged surface. Until a light beam hits the surface, the charge is retained.
Another, no less significant part of the device is a laser, an optical-mechanical system of mirrors and lenses. This mechanism moves along the surface of the shaft a thin and “sharp” beam emitted by a quantum generator (laser). There is reflection from a system of four-sided mirrors, the exposure of a certain surface of the drum, more precisely, its photosensitive spraying. When exhibiting a specific area, the surface becomes conductive, the charge "flows" from this area. Where the charge is removed, a neutral zone is formed.
The effect of the pole difference (plus or minus) causes the powder particles to stick to the shaft. As a result, its negatively charged particles adhere to the region illuminated by the beam. The dye toner located on the rotating shaft exits through a narrow hole and is evenly distributed by the metering blade.
Turning the laser on and off by the control microcontroller forms a bitmap. Using a rotating system of mirrors, the light beam unfolds, image lines are formed on the surface of the drum.
As the line is formed, the stepper motor spins the drum, the next line is formed. Further, the process is repeated many times until the whole picture is “applied”.
The final stage is the transfer of paint to the sheet. The drum, with the image on it, continues to rotate. It is negatively charged. Gradually he reaches the surface of the sheet. He, on the other hand, touches the shaft, positively charged. The particles of ink are attracted by paper. This is how images are transferred.
The principle of printing an image with a laser printer should be understood not so much for proper operation as for eliminating and preventing problems that arise during operation.
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