How a laser printer works. The principle of operation of a laser printer

Suitable for both office and home. To decide whether such a device is needed, you must first understand what this type of device is. "Laser" means that this type of printer prints with a laser, and it also works with dry ink.

The article will talk in more detail about how these devices are arranged, how they work, as well as their main advantages and main disadvantages. All this will help you make the right decision.

Internal arrangement and mechanics

The photoelectric part of xerography is the basis of how the device works. What that laser printer prints on the same principle. Devices are also arranged identically. Unless there are more cartridges in color devices. The table below shows the main components of the laser device, as well as their components.

What is the device made of?
Laser scanning unit	It is a system of lenses and mirrors. Consists of:
	A semiconductor type laser with a lens that focuses automatically.
	Mirrors and their groups that are able to rotate, forming an image.
Image transfer node	Its components are a toner cartridge and a roller that is responsible for charge transfer. The cartridge is equipped with three basic elements for image transfer:
	1. photo cylinder;
	2. shaft with precharge;
	3. a magnetic roller that interacts with the printer's drum.
	The ability of the photocylinder to change its conductivity under the action of light falling on it is especially important in this case. When the photo cylinder is charged, it retains it for a long time, when illuminated, its resistance decreases, as a result of which the charge begins to drain from the surface and the necessary impression appears.
Knot for fixing the image	Responsible for fixing the image on paper. Fixation occurs due to the ability of the toner to melt at high temperatures and the heating element, which contributes to this process.

How it works - 8 steps:

The heating part melts the toner;
The melted clumps of powder stick to the paper;
The scraper removes the remaining toner from the drum;
The drum is electrostatically treated and charged (positive or negative);
With the help of mirrors, an image appears on the surface of the drum;
The drum moves along the magnetic shaft, and the toner puts a picture on it;
The drum transfers the image to the paper by rolling over it;
rolled through the oven, whereby the image is fixed.

Toner

Toner is a consumable. This is a dry powder (can be black or colored), which is the ink for laser printers. As already described above, it works like this: with the help of static, it (powder) is transferred to a charged photoconductor, due to which an image appears. It is subsequently transferred to paper.

Each manufacturer produces an original . Only with a proprietary dye, the company can guarantee the stable operation of the device. Such qualities as magnetism and dispersion are individual for dyes. Devices are made with the expectation of using a specific toner. Filling the cartridge with an alternative powder of dubious quality, the user risks disrupting the device's performance. If the required toner is not available, you can choose a compatible version with identical properties.

Attention! Attempting to use incompatible products may result in serious equipment malfunctions. You may also void your warranty.

You should be aware that toner can be harmful to health while it is in powder form. It must not be allowed to enter the respiratory tract.

When refilling or removing excess substance, it is extremely important to observe the following precautions:

use latex gloves;
wear a respirator or medical mask on your face;
work with the substance only in a well-ventilated area;
We recommend using a special vacuum cleaner to remove excess toner.

Even better - do not refill the cartridge yourself, but entrust this business to the pros. By contacting a service center, you can not worry that the toner will damage the printer or harm your health.

In a printer based on laser printing technology, everything works by using static electricity. How it works? A laser beam hits the photoconductor in the cartridge and forms an image. At the next stage of image formation, the photoconductor comes into contact with the toner and at the point of contact, where the laser shone and changed the charge, the toner sticks. By the same principle, toner sticks to the paper from the photodrum, and then it is baked in the so-called “stove”. The paper comes out warm from the stove. Don't worry, it's already a little cold.

Learn more about the laser printer printing process

When the photosensitive drum rotates, a positive charge is formed on its surface, which is applied to the photo roller using a laser beam. The positive charge attracts the toner particles, which are negatively charged, and they adhere to the surface of the drum.

The sheet of paper is positively charged and passes under the rotating photo roller during the printing process. Negatively charged toner particles are transferred from the drum to the sheet of paper, thus the image is transferred to the paper. Further, the toner, which is on the paper, is fixed under the influence of heat.

Unlike printing on dot-matrix and inkjet printers, where the image is transferred to paper line by line, with laser printing, the text on an A4 sheet is formed in just 3 turns of the drum unit.

Laser printers are based on the printing system used in copiers. In copiers, a special lamp transfers the image from the copied sheet to the photosensitive surface of the drum in the form of an electrostatic charge. The photoconductor converts the optical image created by the light reflected from the copied image into its electrostatic equivalent, which attracts toner particles with the opposite charge to the surface of the drum.

However, the laser printer does not have the original image; instead, it has a matrix of 1s and 0s in its memory that transmits the image. In the case of black and white printing, 1 sends a signal to the microprocessor and a laser beam is directed to the photoconductor. When the beam touches the surface of the drum, a positive charge is formed in this place, and negatively charged toner particles will adhere to the drum in this very place. Accordingly, 0 does not transmit a signal and no charge appears on the surface of the drum, and later these areas will remain white on paper. How to get rid of white stripes when printing, read the article -

Many believe that the laser printer is so named because it burns images onto paper with a laser. However, one laser is not enough to get a quality print.

The most important element of a laser printer is the photoconductor. It is a cylinder covered with a photosensitive layer. Another necessary component of toner is coloring powder. Its particles are fused into a sheet of paper, leaving the desired image on it.

The imaging drum and toner hopper are most often part of the same one-piece cartridge, which in addition has many other important parts - the charge and developer rollers, the cleaning blade and the waste toner bin.

Now let's look at how this all happens in more detail.

Printer steps

An electronic document is sent for printing. At this point, the printed circuit board processes it, and the laser sends digital pulses to the cartridge. By charging the photoconductor with negative particles, the laser transfers an image or text to it that needs to be printed.

When the laser beam hits the drum, it removes the charge and uncharged zones remain on its surface. Each toner particle is negatively charged and in contact with the drum unit, the toner adheres to uncharged fragments under the influence of static electricity. This is called image development.

A special roller with a positive charge presses a sheet of paper against the photoconductor. Because oppositely charged particles attract, the toner sticks to the paper.

Next, the paper with toner is heated to a temperature of about 200 degrees using a thermal shaft of the so-called stove. Due to this, the toner expands and the image is firmly fixed on the paper. Therefore, documents freshly printed on a laser printer are always warm.

The last step is to charge the photoconductor and clean it of any remaining toner using a cleaning blade and waste toner box.

This is how the printing process works. The laser paints the future image with charged particles. The photoconductor catches and transfers the ink powder to the paper. Toner adheres to paper due to static electricity and fuses to it.

The copier works on the same principle.

Benefits of a laser printer

It is believed that the print speed of a laser printer is higher than that of an inkjet printer. On average, this is 27-28 prints per minute. Therefore, they are used to print a large number of documents.

The device does not make much noise during operation. The print quality is very high at a low print cost, which is achieved due to the low consumption and price of the toner. The cost of most models of laser printers is also quite affordable.

For many years there has been a debate about whether a laser printer is harmful to health. The particles of toner used in laser printing are so small that they easily enter the human body, settle and accumulate in the respiratory tract. With constant contact with toner for 15-20 years, headaches, asthma and other diseases can develop.

However, printer manufacturers assure that there is no harm in daily use of the printer. Production technologies are constantly being improved, and cartridges are tested in laboratories.

Danger can arise only when you try to open and refill the cartridge yourself. Toner particles can get into the lungs and are very poorly excreted from the body, so it is better to entrust the refilling of the printer to specialists.

The speed, service life and print quality of laser printers are really on top. This device is indispensable in the work and everyday life of many users and is not as whimsical as capricious inkjet printers, who often have problems with printing when refilling.

If you still got not the most successful model of a laser printer and you did not use it much at all, then do not despair. KupimToner buys new printers from different brands, as well as accessories for them, offering a decent price.

In domestic conditions, laser and inkjet printers are popular. The principle of printing such devices is fundamentally different, which cannot but affect the operational features. In some cases it is best to use laser products, while in others it is best to use inkjet products. However, to make the final choice in favor of a particular device is possible only after considering the scheme of work.

Working principle of inkjet printer

Still, at home, it is the inkjet printer that is most often used. The principle of printing it is to form an image using liquid ink. They are transferred to the media through special nozzles located on the head. The number of such holes depends on the model of the printer. Usually their number ranges from 16-64 pieces.

Since an inkjet printer prints using liquid ink, it dries on the head nozzles if it is left idle for a long time. This requires cleaning of the printing element, which involves the additional consumption of colorants.

Such devices consist of the following components:

supporting structure;
power supply;
print head;
cleaning system;
devices for supplying media;
control node.

A color image is obtained by superimposing three primary colors on top of each other. Black ink is often added to them, so that it is possible to use devices for the usual printing of texts and black-and-white drawings, saving on color inks.

Core Inkjet Printing Technologies

Different models may have their own advantages and disadvantages. The principle of printing representatives of inkjet printers may also differ slightly depending on the technology used. The difference lies only in the way the ink is transferred to the solid media.

The piezoelectric method involves the formation of ink dots on paper using special devices that are connected to the diaphragm. The electric field has a direct effect on the piezoelectric element, and it expands the tube to fill the capillary system. The main advantage lies in the flexible control of the droplet dimensions, which makes it possible to obtain high-quality images with high resolution.
The gas bubble method implies the presence of heating elements directly in the nozzles. Electricity is passed through them. During the heating process, gas bubbles are formed, which push the right portion of liquid ink through the holes. After the heater cools down, a fresh portion of the coloring matter enters through the nozzles. High quality is noted for detailed drawing of lines, but when printing solid areas, there may be slightly blurry places.
The thermal jet method, as in the previous case, involves the use of a heating element. However, a special mechanism is used with it, which allows for faster injection of colorants. As a result, device performance increases. The color palette of the resulting image differs in contrast.

The inks used may vary. Water-based ink contains a soluble dye and certain additives to adjust the viscosity. Their advantage lies in their low cost. Pigment inks are UV and moisture resistant. The print quality in this case is less dependent on the media.

Using continuous ink supply

With the principle of printing an inkjet printer, everything became clear. Special cartridges are used to store dyes. However, there is a special system that allows you to continuously supply ink in order to save money. In this case, the capsule reservoirs are installed directly on the print head.

The system is a set of containers connected by a silicone cable, through which ink is supplied from donors to the main unit. Thanks to this device, the constant presence of the original dyes in the print head is achieved. Many large format office fixtures have a built-in ink system that cannot be seen from the outside.

The principle of operation of the laser device

A completely different branch of the development of printing devices is laser technology, which can be used to achieve high-quality deposition of colorants on paper. The formation of characters and images occurs due to the beam illumination of the device elements with photosensitivity. The resulting copies with text or graphic information are resistant to fading and abrasion.

Inkjet and laser printers have completely different printing principles. Toners act as colorants, which can be transferred to a solid carrier in three ways.

Using a two-component development system. The dye particles needed to be transferred to a special photosensitive drum are not able to be fixed on a magnetic roller without a special magnetic carrier charged as a result of agitation.
With the use of one-component toner without additional impurities. Particles of matter in this case are endowed with magnetic properties. In some devices, electrostatic application can be carried out. With this option, the toner does not require magnetization.
Using a two-component dye, mixed at the factory.

Unlike an inkjet printer, the principle of printing a laser analog is based on building an image using the photographic method. The laser beam hits a special shaft, the surface of which is electrified due to impact ionization of the internal air.

Design of laser devices

Laser printers succeed in obtaining high-quality printing due to technological features. They include the following elements.

The photodrum, which is a cylinder made of aluminum. It is treated with a photosensitive material that tends to change electrical resistance in the presence of lighting.
The magnetic roller is used to transfer the toner from the reservoir directly to the drum or developing roller installed in some models of modern printers.
The doctor blade acts as a cleaning blade. With its help, excess coloring matter is removed from the screen roller. It can be made of plastic, steel or fiberglass.
The waste toner hopper is made in the form of a container. This compartment may be separate from the cartridge or together with it. The filling speed of such a tank depends on the quality of the toner.
The laser unit is designed to create an invisible image on the surface of the photoconductor by highlighting specific areas. The intensity of the beam can vary significantly.
The primary charge roller is made in the form of a metal rod covered with a layer of rubber. This element allows you to ensure the uniformity of the negative charge.
The transfer tape is necessary for applying an intermediate result from color cartridges.
The development unit allows you to transfer the toner directly onto the electrostatic image created on the surface of the photoconductive element.

Laser printing process

Not everyone fully understands the principle of printing laser printers from computer science courses. Inkjet devices operate according to a simplified scheme, so there are no special questions about them. How does the laser printing process work?

First, the photoconductive roller is charged. An electric charge is evenly distributed over its surface by rotating the roller. The rotating rod system reduces voltage and reduces the amount of ozone produced.
A laser scan is performed. At this moment, the charged surface of the shaft passes under the light beam. The laser hits only those places where the coloring matter will be applied in the future.
The toner is applied. A roller that has a negative charge transfers it to the toner. The dye from the hopper is attracted directly to the magnetic shaft, after which it comes into contact with the photoconductive element in those areas where the negative charge remains.
The transfer roller in contact with the solid carrier is no longer negatively charged but positively charged. Particles of the coloring matter fall on the surface of the paper due to electrostatic action.
The toner distributed over the carrier is fixed by heat and pressure. The thermal chamber consists of two shafts between which the paper moves. The temperature is controlled by a special sensor. The dye is melted and incorporated into the texture of the paper.

comparison table

It is suggested to look at the table to compare the properties of inkjet and laser printers, which print principle is very different.

Parameters	Printer type
Parameters	laser	Jet
Text printing
Obtaining color images in the form of diagrams and graphs
Printing photos
Performance
Number of pages printed after replacing ink cartridges

Having briefly considered the principle of printing an inkjet printer, one cannot fail to note the features of operation.

It is not recommended to use the device less than once a week to avoid ink drying out.
It is necessary to purchase high quality dyes, otherwise the head can quickly become clogged.
The correct paper should be used and should be marked as suitable for inkjet printing.
It is essential to keep the product clean, as dust wears out moving parts.

Features of working with laser devices

The main advantage of laser printers is the absence of the need for regular operation. It can even be used once a month. This will not affect the quality of work or wear of parts. However, you must use only original toner cartridges, otherwise there is a high risk of damage to the device. In addition, third-party supplies may simply not work.

Before purchasing a device with a lot of positive reviews, you need to find out additional information about the cost:

Supplies;
wear parts;
one page printout.

Sometimes it turns out that it is easier to purchase a new device than to replace any parts.

Final part

Having briefly considered the principle of printing inkjet and laser printers, we can draw certain conclusions about the acquisition of certain devices. However, the final choice will depend on what goals are pursued during operation. For printing large volumes of text information, it is more profitable to buy laser devices. If you need to get high-quality photos, then it is better to give preference to inkjet counterparts.