Laser printers are widely used for printing documentation in the office and at home. High print quality and speed of operation are due to the design features. In order to understand the principle of operation of the equipment, it is necessary to study the device in detail. It will not be possible to briefly examine this question, but the more detailed we look at everything, the clearer the answer will be.
At the heart of the work laser printer lies the photoelectric principle of xerography. The design includes complex mechanisms and components, which can be divided into three main blocks.
- It is based on a printing mechanism.
- A controller with a raster processor is responsible for scanning.
- Data exchange is carried out using an interface block.
Elements of the printing mechanism:
- photodrum with a static charge that changes depending on the lighting;
- a laser and a system of mirrors ensures that certain areas on the photodrum are illuminated;
- an intermediate block necessary to transfer the image to the final medium;
- a toner storage and supply unit based on a cartridge;
- mechanisms for drawing paper from the tray to the print head;
- heating elements for developing the image on the sheet.
How the cartridge works
The cartridge consists of a toner and a drum. The chemical composition of toner is a crushed polymer material. Depending on the manufacturer, the powders differ in consistency and physical properties. Toner differs from ink in the quality of the resulting image, but you must be careful when working with it.
Important. For high-quality printing on a laser printer it is necessary to change it on time Consumables. It is not recommended to refill low-quality toner cartridges.
The drum is a cylinder with a photoconductive surface. The magnetic roller recharges the toner and the cleaning blade removes unused toner.
How does a laser printer work?
The operating principle of a laser printer is to create a preliminary image on a drum and then transfer it to paper. A high-quality print is obtained by applying dots to the photodrum using a laser and a system of mirrors. The operating principle of a laser printer is based on the physical process of xerography.
To understand how the device prints, you need to study in detail the stages and operating principle of a laser printer:
- Image processing and charging the drum with charged particles.
- Next comes the preliminary creation of the image.
- The next step involves developing with toner.
Fixing occurs using high temperatures. The design ensures high print quality and speed. Technology is constantly evolving, offering new solutions.
Drum charge
In order to generate a preliminary image, you need to create electric charge on the surface of the drum. There may be positive and negative particles, depending on the printer model and design features.
There are two ways to transfer charge:
- The corona wire is a tungsten filament containing inclusions of gold or platinum. Under the influence of voltage, an electric field is created, which is transferred to the drum. With this method, the quality of the printed material deteriorates over time.
- The charge roller is a shaft with a layer of rubber or foam applied to it. When interacting with the drum, electricity is transmitted. This method creates a reduced voltage, which allows you to extend the service life of complex mechanisms.
Exhibition
The process of creating a preliminary image on the image drum is called exposure. On the surface of the drum there is a semiconductor coating, which, when exposed to light, begins to conduct current. Lighting comes from a thin laser beam and a complex system of mirrors.
By given parameters the beam forms an image by removing the charge in the exposed areas. Drawing or text is applied pointwise. The result is a surface of negatively charged particles. The drum rotates using a stepper motor. The dots are drawn along the entire circle.
Development
The image is developed using toner and magnetic shaft. The mechanism is a metal tube with a magnetic core. By rotating, the toner is attracted to the shaft. The metering blade ensures even distribution of paint over the entire surface. The layer is formed by passing toner through the gap between the blade and the drum.
Attention: It is necessary to install the mechanism correctly to avoid defects on the printed document. Excess toner results in dots and streaks.
The magnetic shaft operates cyclically. As it works, new particles are attracted, creating an image. Excess powder is dumped into a special container.
Transfer
The image is also transferred to paper using a charge. Moving mechanisms feed the sheet from the tray to the photodrum, next to which there is a shaft for transferring the image. Toner particles are transferred through the circuit to the paper medium due to static voltage. Excess paint goes back into the hopper. With help special elements, dust and small particles are removed from the surface of the sheet. The charge is restored after a whole cycle using a corotron. The process is then repeated until the entire image is transferred to paper.
Consolidation
The next stage of printing on a laser printer is consolidation. This stage necessary for the image to remain on the paper. Under the influence of high temperatures, the toner begins to melt, which allows it to firmly adhere to the surface. When the sheet passes between two rollers, heating occurs.
Reference. Depending on the model, the stove can heat the powder up to 200–350 °C.
Type of heating:
- Thermal film is used in inexpensive laser printers. It is highly susceptible to mechanical stress.
- The Teflon design heats the surface using a lamp. Reliable and durable design.
Temperature control occurs using a sensor. If the values are exceeded, the device automatically turns off. To prevent the sheet from sticking to the drum, there is a separating mechanism at the outlet. If the basic operating rules are followed, these elements rarely fail.
Color print
Laser color printing is widely used to print high-quality images. Taking into account the fact that the printer creates a subtractive color model, it is possible to obtain any shade. This occurs due to the absorption and reflection of different light waves. When introducing black color, the output is rich colors. A laser printer consists of a large number of modules and blocks that allow you to mix colors and transfer an image onto a sheet. Models differ in technical specifications and the principle of operation.
What printing principle is used in color laser printers?
Unlike a black and white printer, the operating principle of color equipment is different. Before printing begins, the printer processes the image and splits it into monochrome. There are four primary colors used: cyan, magenta, yellow and black. Each of them has a separate compartment. During the printing process, the shades are mixed. Models differ in design and principle of operation.
Color printing methods:
A color laser printer is a high-tech device. The product, as a rule, has its own processor and HDD. The technology of image transfer to the intermediate section is widely used. The method allows you to extend the service life of the product, since there is no contact between the printing mechanism and the paper. Such devices are suitable for use in the office and at home.
In a printer based on laser printing technology, everything works through the use of static electricity. How it works? The laser beam hits the photodrum in the cartridge and forms an image. At the next stage of image formation, the photodrum comes into contact with the toner and the toner sticks at the point of contact where the laser shined and changed the charge. Using the same principle, toner sticks to the paper from the photodrum and is then baked in the so-called “oven”. The paper comes out warm from the stove. Don't be afraid, it's already cooled down a little.
Learn more about the laser printing process
When the photosensitive drum rotates, a positive charge, which is applied to the photo roll using a laser beam. The positive charge attracts toner particles, which are negatively charged, and they stick to the surface of the drum.
The sheet of paper is positively charged and passes under a rotating photo roller during the printing process. The negatively charged toner particles are transferred from the drum to the sheet of paper, thus transferring the image onto the paper. Next, the toner, once on the paper, is fixed under the influence of heat.
Unlike printing on 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 revolutions of the photodrum.
Laser printers are based on the printing system used in copiers. In copiers, a special lamp transfers the image from the sheet being copied to the photosensitive surface of the drum in the form of an electrostatic charge. The image drum converts the optical image created by 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, a laser printer does not have an original image; instead, in its memory there is a matrix consisting of 1s and 0s that transmits the image. In the case of black and white printing, 1 transmits a signal to the microprocessor and directs the laser beam to the photodrum. When the beam touches the surface of the drum, a positive charge is formed at that location, and negatively charged toner particles will stick to the drum at that location. 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 the paper. Read the article about how to get rid of white stripes when printing -
Today it is difficult to imagine life without printing devices. From time to time it is simply necessary to transfer information to paper. Schoolchildren need to print out reports, students need to print out diplomas and coursework, and office employees need to print out documents and contracts.
There are several types of printers. They differ in the printing principle, the format of the paper used, the type of printed materials and other characteristics. Let's consider the principle of operation of two types of printing devices - laser and inkjet.
Working principle of an inkjet printer
First of all, let's look at how it works jet printer. It’s worth mentioning right away that in terms of print quality it lags slightly behind laser. However, the cost of an inkjet printer is significantly lower. This type of printer is perfect for home use. It is easy to handle and easy to maintain.
If we talk about the operating principle of laser and inkjet printers, they are radically different. The main difference is the ink supply technology, as well as the hardware design. Let's first discuss how an inkjet printer works.
The operating principle of this printing device is as follows: an image is formed on a special matrix, after which it is printed on a canvas using liquid ink. There is another type of inkjet printers that have cartridges. Cartridges are installed in a special block. In this design, ink is transferred to the print matrix using the print head. After this, the matrix transfers the image onto paper.
Storing ink and applying it to the canvas
There are several ways to apply ink to canvas:
— gas bubble method;
— piezoelectric method;
— drop-on-demand method.
The piezoelectric method involves the creation of ink dots on the canvas using a piezoelectric element. The tube opens and contracts again, preventing excess ink drops from falling. The gas bubble method is also known as the injected bubble method. They leave an imprint on the canvas due to high temperatures. The nozzle of each printing matrix has a heating element. It takes a fraction of a second to heat up such an element. After heating, the resulting bubbles are transferred to the canvas through nozzles.
The drop-on-demand method also uses gas bubbles. However, this is a more optimized method. Print speed and quality have increased significantly.
Ink in an inkjet printer is typically stored in two ways. The first method involves the presence of a separate reservoir from which ink is supplied to the print head. In the second method, a special cartridge is used to store ink, which is located in the print head. To replace the cartridge, you will have to change the print head itself.
Using Inkjet Printers
Inkjet printers have gained particular popularity due to the fact that these devices have the ability to print in color. An image in color printing is created by superimposing basic tones with varying degrees of saturation on top of each other. The basic set of colors is also known by the abbreviation CMYK. It includes the following colors: black, cyan, purple and yellow. Initially, a set of three colors was used. It included all the colors listed above except black. But even when applying cyan, yellow and magenta colors at 100% saturation, it was still not possible to achieve black, the result was either gray or brown. For this reason, it was decided to add black ink to the main set.
Inkjet printer: operating features
The main indicators of printer performance are usually considered to be print speed, noise characteristics, durability and print quality. Let's consider the performance qualities of an inkjet printer.
The operating principle of such a printer has already been discussed above. Ink is supplied to paper through special printers. An inkjet printer operates very quietly, unlike, for example, needle printers, in which ink is applied through a mechanical impact process. You will not hear the inkjet printer printing; you can only hear the noise of the mechanism that moves the print heads. If we talk about the noise characteristics of inkjet printers in quantitative terms, then when such a device is operating, the noise level does not exceed 40 decibels.
Now let's talk about printing speed. An inkjet printer prints much faster than a pin printer. However, the quality of printing directly depends on such an indicator as speed. In this sense, the faster the print speed, the worse the quality. If you select High Quality Print mode, the process will slow down significantly. The paint on the canvas will be applied carefully. This printer prints at an average speed of 3 to 5 pages per minute. In modern printing devices, this figure has been increased to 9 pages per minute. Color images will take a little longer to print.
One of the main advantages of an inkjet printer is the font. In terms of the quality of font display, an inkjet printer can be compared, perhaps, only with a laser one. You can improve print quality by using good paper. The main thing is to choose paper that can quickly absorb moisture. High image quality can be achieved using paper with a density of 60 to 135 g/m2. Copier paper has proven itself well. Its density is 80 g/m2. To speed up the drying process of ink, some printing devices have a paper heating function. Despite the completely different operating principles of inkjet and laser printers, when using these devices it is possible to achieve the same quality.
Printing paper
An inkjet printer, unfortunately, is not suitable for printing on roll media. It is also not intended for making copies: you will have to use multiple printing.
Disadvantages of an inkjet printer
As mentioned earlier, inkjet printers print using a matrix. An image when printed on an inkjet printer is formed from dots. The most important and valuable element in the entire device is the print head. To reduce the size of the device, many companies integrate the print head into the cartridge. Inkjet and laser printers differ in their printing principles. The disadvantages of inkjet printers include the following:
1. Low printing speed;
2. Ink dries out after prolonged inactivity
3. High cost and short resource of consumables
Advantages of inkjet printers
1. Optimal price/quality ratio. When choosing a printing device, many users are most attracted by the price of this type of printer.
2. The printer has fairly modest dimensions. This makes it possible to mark it even in a small office or office. This will not create any inconvenience for the user.
3. Possibility to refill cartridges yourself. You can simply buy ink and read in the user manual how to refill it correctly.
4. Availability of a continuous ink supply system. This system will significantly reduce printing costs for large volumes.
5. High quality printing of images and photos
6. Big choice Print media used
Laser printer
A laser printer today means a special type of printing equipment designed for applying text or images to paper. This type of equipment has a very unusual history. The principle of operation of a laser printing device began to be discussed only in 1969. Scientific research was carried out over several years.
To improve the operating principle of this device, many methods have been proposed. The world's first copying machine using a laser beam to create a print appeared in 1978. This device It was huge in size, and its cost was off the charts. Some time later, Canon took up this development.
The first desktop laser printer appeared in 1979. This led to other companies beginning to optimize and promote new models of laser printers. The principle of printing itself has not changed. Prints obtained using a laser printer have high performance. They are not afraid of fading or erasing, they are not afraid of moisture. Images produced using a laser printer are highly durable and of high quality.
How a laser printer works
Let us briefly describe the operating principle of a laser printer. An image when printed on a laser printer is applied in several stages. First, a special powder called toner melts under the influence of temperature. It sticks to the paper. After this, the unused toner is removed from the drum with a special scraper and moved to the waste storage tank. The surface of the drum is polarized by a corona generator. An image is formed on the surface of the drum. The drum then moves along the surface of the magnetic roller, which contains the toner. Toner sticks to charged areas of the drum. The drum then comes into contact with the paper and leaves toner on it. Then the paper is rolled through a special oven, in which the powder melts under high temperature and sticks to the paper.
Color laser printer
The process of printing on a color printer differs from black and white by using several shades. By mixing these shades in a certain ratio, you can create primary colors. Typically, laser printers have their own compartment for each color. This is their main difference. Printing color images on such a printer occurs in several stages. First, the image is analyzed, after which the charge distribution is formed. Next, the same sequence of operations is carried out as for black and white printing: a sheet of toner is passed through an oven, where the powder melts and sets with the paper.
Advantages of laser printers
1. High speed print
2. Image endurance and durability
3. Low cost
4. High quality
Disadvantages of laser printers
1. During operation, ozone is released. Print on a laser printer only in a well-ventilated area
2. Bulky
3. High power consumption
4. High price
Conclusion
Having analyzed the operating principle and main characteristics of inkjet and laser printers, we can say that for home use The first type of device is more suitable. They are affordable and small in size. Laser printers are more suitable for offices where large quantities of documents need to be printed.
Page 2 of 2
IN article is being considered principle actions and device modern laser printers. She opens series articles, dedicated principles and problems laser boards.
The image obtained using modern laser printers (as well as matrix and inkjet printers) consists of dots. The smaller these dots and the more frequently they are located, the higher the image quality. The maximum number of dots that a printer can print separately on a 1-inch (25.4 mm) section is called resolution and is characterized in dots per inch, and the resolution can be 1200 dpi or more. The quality of text printed on a laser printer with a resolution of 300 dpi is approximately the same as typographical. However, if the page contains drawings containing shades of gray, then to obtain a high-quality graphic image you will need a resolution of at least 600 dpi. With a printer resolution of 1200 dpi, the print is almost photographic quality. If you need to print a large number of documents (for example, more than 40 sheets per day), a laser printer seems to be the only reasonable choice, since for modern personal laser printers the standard parameters are a resolution of 600 dpi and a print speed of 8...1 2 pages per minute.
OPERATING PRINCIPLE OF A LASER PRINTER
The laser printer was first introduced by Hewlett Packard. It used the electrographic principle of creating images - the same as in photocopiers. The difference was in the method of exposure: in photocopiers it occurs using a lamp, and in laser printers, lamp light replaced the laser beam.
The heart of a laser printer is an Organic Photo Conductor, often called a print drum or simply a drum. It is used to transfer images onto paper. The photodrum is a metal cylinder coated with a thin film of photosensitive semiconductor. The surface of such a cylinder can be provided with a positive or negative charge, which remains until the drum is illuminated. If any part of the drum is exposed, the coating becomes conductive and charge flows away from the illuminated area, creating an uncharged zone. This is a key point in understanding how a laser printer works.
Another important part of the printer is the laser and the optical-mechanical system of mirrors and lenses that moves the laser beam along the surface of the drum. The small-sized laser generates a very thin beam of light. Reflecting from rotating mirrors (usually tetrahedral or hexagonal), this beam illuminates the surface of the photodrum, removing its charge at the exposure point.
To obtain a spot image, the laser is turned on and off using a control microcontroller. The rotating mirror turns the beam into a line of latent image on the surface of the photodrum.
After forming the string, special stepper motor turns the drum to form the next one. This offset corresponds to the printer's vertical resolution and is typically 1/300 or 1/600 inch. The process of forming a latent image on a drum is reminiscent of the formation of a raster on a television monitor screen.
Two main methods of preliminary (primary) charging of the surface of the photocylinder are used:
Ø using a thin wire or mesh called “corona wire”. The high voltage applied to the wire creates a glowing ionized area around it, called a corona, and gives the drum the necessary static charge;
Ø using a pre-charged rubber roller (PCR).
So, an invisible image in the form of statically discharged dots is formed on the drum. What's next?
DEVICECARTRIDGE
Before we talk about the process of transferring and fixing an image on paper, let’s look at the device of the cartridge for the Laser Jet 5L printer from Hewlett Packard. This typical cartridge has two main compartments: the waste toner compartment and the toner compartment.
Main structural elements of the waste toner compartment:
1 - Image drum(Organic Photo Conductor (OPC) Drum). It is an aluminum cylinder coated with an organic photosensitive and photoconductive material (usually zinc oxide) that is capable of retaining the image created by the laser beam;
2 - Shaft primary charge(Primary Charge Roller (PCR)). Provides a uniform negative charge to the drum. Made from a conductive rubber or foam base applied to a metal shaft;
3 - « Viper» , squeegee, cleaning blade(Wiper Blade, Cleaning Blade). Clears the drum of any remaining toner that has not been transferred to the paper. Structurally, it is made in the form of a metal frame (stamping) with a polyurethane plate (blade) at the end;
4 - Blade cleaning (Recovery Blade). Covers the area between the drum and waste toner box. Recovery Blade passes the toner remaining on the drum into the hopper and prevents it from spilling out in the opposite direction (from the hopper onto the paper).
Main structural elements of the toner compartment:
1 - Magnetic shaft(Magnetic Developer Roller, Mag Roller, Developer Roller). Represents metal tube, inside of which there is a stationary magnetic core. Toner is attracted to the magnetic shaft, which, before being supplied to the drum, acquires a negative charge under the influence of direct or alternating voltage;
2 - « Doctor» (Doctor Blade, Metering Blade). Provides uniform distribution of a thin layer of toner on the magnetic roller. Structurally, it is made in the form of a metal frame (stamping) with a flexible plate (blade) at the end;
3 - Sealing blade magnetic shaft(Mag Roller Sealing Blade). A thin plate similar in function to the Recovery Blade. Covers the area between magnetic shaft and toner supply compartment. Mag Roller Sealing Blade allows toner remaining on the magnetic roller to flow into the compartment, preventing toner from leaking backwards;
4 - Bunker For toner (Toner Reservoir). Inside it is the “working” toner, which will be transferred to the paper during the printing process. In addition, a toner activator (Toner Agitator Bar) is built into the hopper - a wire frame designed for mixing toner;
5 - Seal, check (Seal). In a new (or regenerated) cartridge, the toner hopper is sealed with a special seal that prevents toner from spilling during transportation of the cartridge. This seal is removed before use.
PRINCIPLE OF LASER PRINTING
The picture shows a cross-section of the cartridge. When the printer turns on, all components of the cartridge begin to move: the cartridge is prepared for printing. This process is similar to the printing process, but the laser beam is not turned on. Then the movement of the cartridge components stops - the printer goes into a ready-to-print state.
After sending a document for printing, the following processes occur in the laser printer cartridge:
Charger drum. The Primary Charge Roller (PCR) uniformly transfers a negative charge to the surface of the rotating drum.
Exhibition. The negatively charged surface of the drum is exposed to the laser beam only in those places where the toner will be applied. When exposed to light, the photosensitive surface of the drum partially loses its negative charge. Thus, the laser exposes a latent image to the drum in the form of dots with a weakened negative charge.
Application toner. At this stage, the latent image on the drum is converted into a visible image with the help of toner, which will be transferred to paper. The toner located near the magnetic roller is attracted to its surface under the influence of the field of the permanent magnet from which the core of the roller is made. When the magnetic shaft rotates, the toner passes through a narrow slot formed by the “doctor” and the shaft. As a result, it acquires a negative charge and sticks to those areas of the drum that were exposed. “Doctor” ensures uniform application of toner onto the magnetic roller.
Transfer toner on paper. Continuing to rotate, the drum with the developed image comes into contact with the paper. On the reverse side, the paper is pressed against the Transfer Roller, which carries a positive charge. As a result, negatively charged toner particles are attracted to the paper, which produces an image “sprinkled” with toner.
Consolidation Images. A sheet of paper with an unfixed image is moved to a fixing mechanism, which consists of two contacting shafts, between which the paper is pulled. The Lower Pressure Roller presses it against the Upper Fuser Roller. The top roller is heated, and when it touches it, the toner particles melt and adhere to the paper.
Cleaning drum. Some toner does not transfer to the paper and remains on the drum, so it needs to be cleaned. This function is performed by the “viper”. All toner remaining on the drum is removed by a wiper into the waste toner bin. At the same time, the Recovery Blade covers the area between the drum and the hopper, preventing toner from spilling onto the paper.
"Erase" Images. At this stage, the latent image created by the laser beam is “erased” from the surface of the drum. Using the primary charge shaft, the surface of the photodrum is evenly “covered” with a negative charge, which is restored in those places where it was partially removed under the influence of light.
Laser and inkjet printers are popular at home. The printing principle of such devices is radically different, which cannot but affect the operational features. In some cases, it is best to use laser products, and in others, inkjet products. However, the final choice in favor of one device or another can be made only after considering the operating diagram.
Operating principle of inkjet printing device
Still, at home, an inkjet printer is most often used. The principle of printing 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 printing device. Usually their number ranges from 16-64 pieces.
Since the printing principle of an inkjet printer involves the use of liquid ink, if it is not used for a long time, it dries out on the head nozzles. This requires cleaning the printing element, which involves additional consumption of ink.
Such devices consist of the following components:
- supporting structure;
- power supply;
- print head;
- cleaning system;
- media supply devices;
- control node.
A color image is obtained by superimposing three basic colors on top of each other. Black ink is often added to them to make it possible to use the device for regular printing of texts and black-and-white drawings, saving on color inks.
Basic Inkjet Printing Technologies
Different models may have their own advantages and disadvantages. The printing principle of inkjet printers may also differ slightly depending on the technology used. The only difference is in the method of transferring the ink to the solid medium.
- The piezoelectric method involves the formation of ink dots on paper using special devices that are connected to a diaphragm. The electric field has a direct effect on the piezoelectric element, and it opens the tube to fill the capillary system. The main advantage is the flexible control of the droplet dimensions, which makes it possible to obtain high-quality, high-resolution images.
- The gas bubble method involves the presence of heating elements directly in the nozzles. Passes through them electricity. During the heating process, gas bubbles are formed, which push the required portion of liquid ink through the holes. After the heater cools down, a fresh portion of the coloring agent enters through the nozzles. High quality is observed when drawing detailed lines, but when printing solid areas there may be slightly blurred areas.
- The thermal jet method, as in the previous case, involves the use of a heating element. However, a special mechanism is used with it to ensure faster injection of dyes. In this regard, the performance of devices increases. The color palette of the resulting image differs in contrast.
The ink used may have different compositions. Water-based inks contain soluble dye and certain additives to adjust the viscosity. Their advantage lies in their low cost. Pigment ink is resistant to ultraviolet radiation and humid environments. Print quality in this case depends less on the media.
Using continuous ink supply
Everything became clear with the principle of printing with an inkjet printer. Special cartridges are used to store dyes. However, there is a special system that allows for a continuous supply of ink in order to save money. In this case, 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, a constant presence of the original dyes in the print head is achieved. Many large format office products have a built-in ink supply system that cannot be seen from the outside.
Operating principle of a laser device
A completely different branch of the development of printing devices is laser technology, with which it is possible to achieve high-quality application of coloring substances to paper. The formation of symbols and images occurs due to the illumination of light-sensitive device elements by a beam. Received copies with text or graphic information are resistant to fading and abrasion.
Inkjet and laser printers have completely different printing principles. Toners act as coloring substances, which can be transferred to a solid carrier in three ways.
- Using a two-component development system. The dye particles required for transfer to a special light-sensitive drum are not able to be fixed on the magnetic shaft without a special magnetic carrier that is charged as a result of mixing.
- Using single-component toner without additional impurities. In this case, the particles of the substance are endowed with magnetic properties. Some devices may use electrostatic application. With this option, the toner does not require magnetization.
- Using a two-component colorant mixed in the factory.
Unlike an inkjet printer, the printing principle of a laser analogue is based on constructing 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 are able to produce high-quality printing due to technological features. They include the following elements.
- The photodrum is a cylinder made of aluminum. It is treated with a photosensitive material that tends to change electrical resistance in the presence of light.
- The magnetic roller is used to transfer toner from the reservoir directly to the drum or developing roller installed in some models of modern printers.
- The squeegee serves as a cleaning blade. It is used to remove excess coloring matter from the raster 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 or together with the cartridge. The filling speed of such a reservoir depends on the quality of the toner.
- The laser unit is designed to create an invisible image on the surface of the photodrum by illuminating specific areas. The intensity of the beam can vary significantly.
- The primary charge roller is made in the form of a metal rod coated with a layer of rubber. This item allows you to ensure uniformity of the negative charge.
- Transfer tape is necessary for applying intermediate results from color cartridges.
- The developing unit allows you to transfer 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. The 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.
- Laser scanning is performed. At this moment, the charged surface of the shaft passes under the light beam. The laser hits only those places where the dye will be applied in the future.
- Toner is being applied. The roller, which 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 a negative charge remains.
- The portable roller in contact with the solid carrier is supplied with a positive rather than a negative charge. Particles of coloring matter fall onto the surface of the paper due to electrostatic action.
- The toner, distributed across the media, is fixed through heat and pressure. The thermal chamber consists of two shafts between which paper moves. The temperature is controlled using a special sensor. The coloring matter melts and is embedded in the texture of the paper.
comparison table
It is suggested that you take a look at the table to compare the properties of inkjet and laser printers, the printing principles of which are very different.
Options | Printer type |
|
Laser | Jet |
|
Text printing | ||
Obtaining color images in the form of diagrams and graphs | ||
Printing photos | ||
Performance | ||
Number of pages printed after replacing cartridges | ||
Having briefly examined the printing principle of an inkjet printer, it is impossible not to note the operating features.
- It is not recommended to use the device less than once a week to avoid the ink drying out.
- It is necessary to purchase dyes High Quality, otherwise the head may quickly become clogged.
- Suitable paper must be used and it must be marked as suitable for inkjet printing.
- It is necessary to keep the product clean, as dust causes wear on moving parts.
Features of working with laser devices
The main advantage of laser printers is that they do not require regular operation. It can be used even 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 device failure. Additionally, third-party supplies may simply not work.
Before purchasing a device with many positive feedback, need to know Additional information about the cost:
- Supplies;
- wear parts;
- one page printouts.
Sometimes it turns out that it is easier to purchase a new device than to replace any parts.
Final part
Having briefly examined the printing principle of inkjet and laser printers, we can draw certain conclusions about the purchase of certain devices. However, the final choice will depend on what goals are being pursued during operation. For high volume printing text information It is more profitable to buy laser devices. If you need to get high-quality photographs, then it is better to give preference to inkjet analogues.
Loading...
