There are two main printing technologies on the market today for printing devices: piezoelectric and thermal inkjet.

Piezoelectric printing technology is developed on the ability of piezoelectric crystals to deform under the influence of electricity. Due to the use of this technology, it became possible to control printing, namely: to monitor the size of the drop, the speed of its exit from the nozzles, as well as the thickness of the jet, etc. One advantage of such a system is that the droplet size can be controlled. This ability allows you to get better images.

To date, experts have proven that the reliability of such systems is much higher than other inkjet printing systems.

When using this technology, the print quality is very high. Even universal and inexpensive models allow you to get images of the highest quality and high resolution. Also, the most important advantage of PU with a piezo system is high color rendering, which allows the image to look bright and saturated.

Epson technologies - time-tested quality

The printheads of EPSON inkjet printers are of high quality, and this is precisely what explains their high price. If you use a piezoelectric printing system, then you are guaranteed reliable operation of the printer, and the print head does not dry out and does not clog, due to the fact that it has minimal contact with air. The piezoelectric printing system was developed and implemented by EPSON, and only EPSON holds a patent for this system.

The thermal inkjet printing principle is used in Canon, HP, Brother printers. By heating the ink, they are transferred to the paper. By means of an electric current, liquid ink is proportionally heated, which is the reason for the name of this printing method - thermal inkjet. An increase in temperature reproduces a heating element, which is located inside the thermal structure. With a strong increase in temperature, the main part of the paint evaporates, the pressure in the structure quickly rises, and a small drop of paint comes out of the heat chamber through a precision nozzle. This process is repeated repeatedly after one second.

The main disadvantage of the thermal inkjet method is that with such a printing technology, enough a large number of precipitation, which over time can disable it. Also, this scale clogs the nozzles over time, which leads to a loss in quality and print speed of the printer.

Also, devices that use thermal inkjet printing, due to constant temperature fluctuations, the print heads deteriorate, as it corny burns out under the influence of enormous temperature. This is the main disadvantage of such devices. The period of operation of the Epson PG MFP is absolutely identical to the service life of the device itself. This was made possible thanks to the high-quality materials from which the print head was developed. Customers who use thermal inkjet printing often need to change the print head, as the high temperature will often cause it to burn out, greatly increasing financial expenses. The quality of the print head will also make a huge difference if users are using remanufactured cartridges.

Using an Epson inkjet printer in conjunction with refillable cartridges is very beneficial, as it improves the quality of the printer and reduces the cost of each printed image.

The print head of EPSON printers is of great importance not only for the stable operation of the printer. PG Quality allows you to increase print quality and print speed. Also, if the print head does not come into contact with air and dries out, the user will not have to change it, and therefore spend money in vain. Devices that use the thermal inkjet principle of operation can overheat greatly, and, accordingly, the print head can also overheat, which, if overheated, can simply burn out and get out of the standing.

As numerous checks and tests show, in order to print as economically as possible and at the same time be bright and effective, engineers recommend using EPSON printers with CISS. EPSON devices work much longer and more efficiently with the LF system than other similarly priced remote control units from other manufacturing companies.

Epson is a trusted manufacturer of quality products that make your job easier and more productive.

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Brief characteristics of inkjet piezoelectric and thermal inkjet printing technology

Catalog with inkjet piezoelectric printing technology.

The most common printers today are based on inkjet technology: crushed dye droplets are sprayed onto the material. Typically, as in dot matrix printers, the print head moves across the media feed direction to form an image stripe, and then the media shifts to print the next stripe. However, instead of needles, the head has many nozzles for ejecting paint.

In inkjet ink printing technology, two technological branches have developed:

• thermal jet, in which the activation of the paint and its release occur under the influence of heating;
• piezoelectric, in which the ejection of paint occurs under pressure created by the oscillation of the membrane.

Piezoelectric inkjet technology

The piezoelectric system, created on the basis of an electromechanical device and brought to commercial readiness by Epson (a subsidiary of the Japanese Seiko), was first used in Epson inkjet printers back in 1993. Successfully used so far (2011).

Drop ejection system

Piezo technology is based on the property of certain crystals called piezocrystals (an example is quartz crystals in now common quartz crystals). wrist watch), deform under the action of an electric current; thus, the term defines an electromechanical phenomenon. it physical property allows some materials to be used to create a miniature "ink pump" in which a positive to negative voltage change will cause a small volume of ink to be compressed and vigorously ejected through an open nozzle. As with the formation of an ink jet due to thermal effects, the droplet size here is determined by physical characteristics ejection chamber (firing chamber) and the pressure created in this chamber due to the deformation of the piezocrystal.

Modulation, i.e., changing the size of the drop, is carried out by changing the amount of current flowing through the ejection mechanism. As with thermal printers, the frequency of the piezoelectric ejection depends on the potential frequency of the electrical impulses, which in turn is determined by the time it takes for the camera to return to its “quiet” state, when it is filled with ink and ready for the next work cycle. Piezo technology is highly reliable, which is very important because the print head, for purely economic reasons, cannot be part of a replaceable ink cartridge, as in thermal systems, but must be rigidly connected to the printer.

Advantages and disadvantages

For both thermal and piezoelectric systems, the performance is determined by many factors. The ability to change the size of the dot gives piezo technology certain advantages.

On the other hand, piezo technology faces some purely physical limitations. For example, the large geometric dimensions of the electromechanical ejection chamber mean that the vertical density of the nozzles must be less than that of thermal counterparts. Not only does this limit the prospects for further development, but it also means that to achieve higher resolution and uniformity in high quality printing, multiple passes of the print head over the same page are required.

A stationary printhead is somewhat cost-effective because it does not have to be replaced. However, this advantage is partially offset by the risk of air entering the system when changing the cartridge. This clogs the nozzles, reduces print quality, and requires several cleaning cycles to restore normal system performance. Another limitation for piezo systems so far concerns the use of dye-based inks: when using pigment inks, which have more high quality, but at the same time they have a higher density, there is also a risk of clogging of the nozzles.

prospects

The piezoelectric print head, based on prior technology, has lower development costs, but is noticeably more expensive to manufacture. At present, such advantages of piezoelectric heads as high reliability and the ability to change the size of the droplet are very significant and make it possible to manufacture products of very high quality.

Vertical resolution

The number of vertical positions is primarily related to the number of vertical nozzles on the print head (lines per inch). Since there are difficulties in creating a print head that includes elements that span two vertical lines at once, two separate rows of nozzles are placed next to each other.

To achieve an acceptable print speed, the maximum number of lines must be printed during each pass of the printhead. In this situation, the manufacturer must make a choice between speed (higher print head and maximum number of nozzles) and production costs(minimum number of nozzles).

Horizontal Resolution

The number of horizontal positions, called drops per inch (dpi), is a function of the frequency at which drops are ejected and the speed at which the print head moves along the horizontal axis. A controlled nozzle at certain moments discretely ejects drops of ink and thus draws a line.

The main difficulty for the manufacturer is the combination of quality (maximum droplets per line) and speed (minimum droplets per line to achieve higher speed). Droplet ejection speed is from 10 to 20 thousand per second. By varying this frequency or the speed of the print head carriage, the optimum horizontal droplet density can be achieved.

Physiological factors and color perception

The perception of the quality of a color document is closely related to the physiology of human vision. Taking into account some individual deviations, the human eye is able to distinguish only colors having a wavelength in the range from 380 nm (violet) to 780 nm (red). Within this spectrum, the human brain can distinguish about a million shades of colors (again with small individual differences).

The perceived color spectrum plays an important role in visually evaluating differences in the quality of printed documents: printers capable of reproducing more shades of color will produce documents that human vision will subjectively attribute higher quality.

Number of colors

The total number of possible colors in which an elementary point can be colored corresponds to the number of addressable elementary colors. With three primary colors, you can get eight basic colors: cyan (Cyan), magenta (Magenta), yellow (Yellow), red (Cyan + Yellow), green (Yellow + Cyan), blue (Cyan + Magenta), white and black. .

This system is binary in that color points may or may not be present. If we apply the halftone gray scale principle to these three primary colors, thus creating color shades, we get 256 shades for each of the three primary colors and thus 256 to the third power of possible color combinations per dot element. In other words, this number is greater than what the human eye can discern.

Drop size

The drop size is a complex function of the pressure at which the ink is ejected and the diameter of the nozzle. Usually the droplet size remains unchanged. In certain cases, the size may change and this technology is known as variable droplet printing.

There is a definite relationship between the size of the drop and the size of the dot reproduced on paper. Theoretically, a 20 picolitre drop would make a 60 micron dot (that's approximately one four hundredth of an inch), while a 2 picoliter drop would make a 30 micron dot barely visible to the human eye.

Resolution matrix M

Resolution is the most easily quantified parameter in determining the print quality of a document. Resolution measures the precision with which dots are placed on the page.

The resolution matrix specifies, for any given point, the total number of possible positions. With dual print head technology, there can be two different matrices, one for color printing and the other for black and white. The matrix allows you to create color levels for each elementary point. Since resolution is the result of combining two different technological processes, the horizontal and vertical resolution may differ.

The latest advance in inkjet printing at the time was the horizontal resolution of 2400 dpi, which makes it possible to place 2400 print dots per inch of printed line, which is twice the most common standard today.

Thanks to the precision of printing and the microscopic droplet size of 7 picoliters, such high results are achieved that the image raster becomes completely indistinguishable for human vision. The 2400 dpi resolution is thus intended for printing documents that require the highest possible resolution and impeccable quality.

Because print speed is highly dependent on the number of dots printed, printing at 2400 x 1200 resolution will be slightly slower than printing at lower resolutions.

Inkjet printers work on one of two technologies. The first is thermal jet: the dye is ejected onto the work surface under the influence of temperature. In the second, the dye is transferred to the surface under pressure, which occurs when the membrane vibrates. This is what is called piezoelectric printing. Let's take a look at its features.

Depending on the method of ink supply, the process can be continuous (constant ink supply) and pulsed (droplet supply is regulated, time intervals are set). In the first case, a high speed of applying the image is achieved, in the second - the accuracy of the parameters.

Epson print head

The head of the printing mechanism consists of nozzles, the diameter of which is less than the thickness of a human hair. It moves perpendicular to the printed material and leaves ink on it. This results in high-quality images with high detail and clarity.

The essence of technology

Piezoelectric inkjet printing gets its name from the piezo crystals. The technology has been used since the 70s of the last century, although it was invented almost a hundred years earlier. Its discovery belongs to P. Curie and J. Curie.

Scientists described the essence of the piezoelectric effect as follows: electric charges of opposite signs appear on crystalline bodies under pressure. If you do not put pressure on these bodies, but stretch them, then the charges will change their sign to the opposite. When a positive charge is changed to a negative charge, the crystals change in size and act like a piston, squeezing the paint out of the nozzles.

In practice, this means that an alternating current can be applied to the piezoelectric elements, under the influence of which they will contract and expand, creating vibrations. To obtain the desired image, it is enough to change the electric field. The volume of the drop varies and depends on the diameter of the nozzles of the print head, the pressure, the size of the ejection chamber.

High detail of images allows you to print photos on special paper

Technology development by Epson

The principle of piezoelectric inkjet printing in printers is implemented and patented by Epson. She released equipment that works according to this technique at the end of the twentieth century.

On the initial stage development of the method, crystal plates were built into the head of the device. Later they were replaced by lamellar piezo transducers. Since 1994, all Epson devices of the Stylus series have been equipped with such lamellas. The company has a monopoly on the production of such equipment. To do this, Epson representatives had to obtain several thousand patents in different countries.

Despite the fact that the piezo technique is identified with the Epson name, the first devices of this type were created by Siemens in 1977. In them, the role of the transducer was performed by piezotubes.

Epson Piezo Inkjet Printer

Features of printing on inkjet printers

Plate-type piezoelectric transducers have replaced tubular and flat ones. They are compact, provide high-frequency spraying of the dye.

Modern printers are equipped with plate-type piezoelectric transducers that are sensitive to electrical impulses. When electrically charged, they bend and press on the meniscus of the ink tank. The reservoir pushes the ink onto the paper.

After that, the transducer is set in reverse motion and takes away the meniscus. The reservoir increases in size, due to which traction is created and it is filled with ink again.

Printing on inkjet printers has the following features:

• Meniscus control. Thanks to the active control and the absence of heating in the system, only the main droplets are emitted from the nozzles, without the so-called "satellites". The image is clear, with well-defined contours. Improves color rendering.
• Drop volume setting. With a smaller droplet volume, quality is improved, but productivity is reduced. By adjusting their size, it is possible to choose the optimal ratio between the duration of the process and the characteristics of the print.
• Applying paint with microdrops. This way it is possible to achieve the highest possible resolution, but only devices that print with a resolution of 2880x1440 dpi have this option.

The volume of microdroplets in Epson printers is 2 pl. This is the lowest indicator for inkjet equipment. For Lexmark printers, the drop size reaches 3 pl, for HP - 4 pl.

Another feature of piezoelectric inkjet printing is ink. They do not contain additives and additives, as, for example, in inks for thermal inkjet devices. The compositions differ in electrical conductivity, degree of viscosity, they are not interchangeable.

Ink bottles are included with the printer but can be purchased separately

Advantages and disadvantages of piezo printing

With the help of piezoelectric technology, it is possible to take control of the entire process of inkjet printing - from the choice of droplet volume and jet thickness, to the speed of ejection of ink onto paper. This feature allows you to more accurately select settings for specific tasks, materials and formats of printing.

Other benefits of piezo printing include:

• high quality, natural color reproduction - suitable for making photographs;
• system reliability - the head is installed directly on the printer, and not on a replaceable cartridge, thanks to which it lasts a long time;
• the ability to work with different images - the desired characteristics of the image are achieved;
• Energy Efficient - Unlike dot matrix printers, you don't need to apply pressure to move the print head. special efforts because it has a small mass.

However, the technology is not without drawbacks. Sometimes, to obtain a high-quality result, it is necessary that the print head passes over the working surface several times. This increases the cost and increases the print time.

When changing cartridges, there is a risk of air entering the nozzles. They become clogged and the print quality deteriorates noticeably. To correct the situation, cleaning of the mechanism is required.

Epson Stylus Printer Cartridges

For printed materials special requirements. Since the ink is quite liquid, on loose paper it may bleed and the outlines of the image will be fuzzy. Therefore, it is better to use high quality media, such as coated paper.

A few years ago, Epson developed a new ink that can print on almost any paper. They are resistant to UV radiation and moisture.

Watch the video review of the Epson L800 piezoelectric inkjet printer:

Results

• Piezoelectric inkjet printing technology relies on the ability of piezoelectric crystals to vibrate when subjected to an electric current.
• Thanks to the ability to adjust the droplet size, it is possible to obtain high-quality images with realistic color reproduction.
• The system is more reliable than other types of inkjet printing.
• The technology is patented by EPSON and cannot be used in printers from other manufacturers.

There are two main printing technologies in the inkjet printer market: piezoelectric and thermal inkjet.

The differences between these systems are in the way the ink drop is brought to the paper.


Piezoelectric technology was based on the ability of piezocrystals to deform under the influence of an electric current on them. Thanks to the use of this technology, full control of printing is carried out: the size of the drop, the thickness of the jet, the speed of ejection of the drop onto the paper, etc. are determined. One of the many advantages of this system is the ability to control the droplet size, which allows you to get high-resolution prints.

The reliability of the piezoelectric system has been proven to be significantly higher compared to other inkjet systems.

The print quality of piezoelectric technology is extremely high: even the most versatile low-cost models produce near-photographic quality and high resolution prints. Also, the advantage of printing devices with a piezoelectric system is the naturalness of color reproduction, which becomes really important when printing photos.

The printheads of EPSON inkjet printers have a high level of quality, which explains their high cost. With a piezoelectric printing system, reliable operation of the printing device is ensured, and the print head rarely fails and is installed on the printer, and is not part of the replacement cartridges.

The piezoelectric printing system was developed by EPSON, it is patented and its use is prohibited by other manufacturers. Therefore, the only printers that use this printing system are EPSON.

Thermal inkjet printing technology used in Canon, HP, Brother printers. The supply of ink to paper is carried out by heating them. The heating temperature can be up to 600°C. The quality of thermal inkjet printing is an order of magnitude lower than that of piezoelectric printing, due to the inability to control the printing process due to the explosive nature of the drop. As a result of such printing, satellites (satellite drops) often appear, which interfere with obtaining high quality and clarity of prints, leading to distortion. This disadvantage cannot be avoided, as it is inherent in the technology itself.

Another disadvantage of the thermal inkjet method is the formation of scale in the print head of the printer, since the ink is nothing more than a collection chemical substances dissolved in water. The scale that forms over time clogs the nozzles and significantly spoils the print quality: the printer starts to streak, color reproduction deteriorates, etc.

Due to constant temperature fluctuations in devices using thermal inkjet printing technology, the print head is gradually destroyed (burns out under the action of high temperature when the fusers overheat). This is the main disadvantage of such devices.
The service life of the print head of EPSON printers is the same as that of the device itself, due to the high quality of the PG workmanship. Users of thermal inkjet devices will have to buy a new print head and replace it every time, which not only reduces the durability of the printer, but also significantly increases the cost of printing.
The quality of the print head is also important when using non-original consumables, in particular CISS.

The use of CISS allows the user to increase the volume of printing by 50%.
The print head of EPSON printers, as already mentioned more than once in this article, is of high quality, due to which an increase in print volumes does not negatively affect the operation of the printer, but rather allows the user to get maximum savings without compromising print quality.

Due to the characteristics of printers using thermal inkjet technology, an increase in print volumes can lead to the failure of the printer's PG.

Observations show that in order to obtain maximum savings with perfect print quality, it is more expedient to use EPSON printers with CISS. EPSON printers work with the continuous ink supply system more stable than printers from other manufacturers.

What are the technologies?

Photo printers have almost universally replaced conventional inkjet models. This is quite natural and is a consequence of technological progress, because all modern A4 inkjet photo printers easily perform the function of universal printing devices, easily coping with both text and work schedule, and with photo printing, the quality is not inferior to the products of a photo lab.

In order to understand how the many photo printer models available in stores differ from each other, and which one is more likely to satisfy your need for obtaining quality photos, we will talk about the principles of imprint formation in such devices.

Currently, two fundamentally different types of home photo printers are being produced: inkjet and sublimation.

Inkjet photo printing

The first inkjet printer appeared in 1984, and we owe it to the American company Hewlett-Packard. The printing technology of such printers is hidden in the name: the image on paper is formed by jets of ink that are ejected from the print head. By the way, it was inkjet printers that made multi-color printing available, since black ink could be replaced or supplemented with inks of other colors. There are three inkjet printing technologies: Epson and Brother use piezoelectric technology, Canon use bubble technology, Lexmark and Hewlett-Packard use thermal inkjet technology. Each technology has its own zest, but in principle they are all extremely close, and the differences come down to how the ejection of ink drops from the nozzles onto the paper is organized.

Piezoelectric printing technology

Piezoelectric technology is based on the property of piezoelectric crystals to deform when an electric current is applied to them. Piezocrystals act as mini-pumps that eject a strictly defined amount of ink onto paper. Among the advantages of such a system is the possibility of flexible control of the droplet size, which is carried out at the electrical level, which simplifies the production of high-resolution prints. It is believed that the reliability of such a system is significantly higher than that of all other inkjet printing systems. The reverse side of the advantages is the comparative high cost of the print head, so it is usually installed in the printer, and not part of a replaceable cartridge. Unfortunately, the piezoelectric head is very afraid of air or counterfeit ink getting into the nozzles. In both cases, you can get clogged nozzles, followed by head replacement, the cost of which can be comparable to the price of the printer itself. In addition, to keep the nozzles in working order, it is necessary to periodically print at least something on such a printer, otherwise ink residues can also clog the nozzles.

However, the new generation of Epson branded ink allows you to forget about this shortcoming. Appeared and pigment ink Epson DURAbrite is a new generation in which microscopic homogeneous ink particles are in a liquid polymer. Such ink practically does not blur on any paper, which allows to increase print resolution and have high light and moisture resistant properties.

The quality of piezoelectric printing is extremely high: even inexpensive universal models can produce prints of almost photographic quality with high resolution. Another advantage of Epson printers is the naturalness of color reproduction, which is especially critical when printing photographs. The only "but": all these advantages are realized only when using branded ink, and master fakes on the Russian market great amount. There is only one way out - to buy ink exclusively in large companies that are official dealers of the manufacturer. Do not forget that a broken printer with a "left" cartridge is automatically removed from the warranty.

Thermal inkjet printing technology

Thermal jet technology, which, by the way, was also used in the world's first serial inkjet printer The HP ThinkJet differs in that ink heating is used for printing: in this case, part of the ink is heated, and part, due to excess pressure, is ejected through the nozzle. The process of heating and cooling is repeated several thousand times within one second, the heating temperature is up to 600°C, and the time of the thermal pulse itself does not exceed two millionths of a second. All modern HP models feature proprietary PhotoREt hardware and software technology, which is responsible for the most realistic color reproduction and high speed color printing.

The quality of thermal inkjet printing is very close to the quality of piezoelectric printing, besides, the manufacturing technology of the print head is close to the technology of manufacturing chips, so the heads are cheaper than piezoelectric ones and, as a rule, are built into a replaceable ink cartridge. Naturally, such a cartridge is somewhat more expensive than just a sealed ink container, but a "non-original" cartridge will no longer be able to completely disable the printer.

Bubble printing technology

Canon's bubble technology is a special case of thermal inkjet printing, in which ink is ejected solely by gas bubbles formed when the ink is heated, with the heating element located to the side of the nozzle, rather than behind it, as in classic thermal inkjet printers. Canon specialists knowingly invested a lot of money in the development of a proprietary print head using FINE technology (Full-photolithography Inkjet Nozzle Engineering), which means “photolithographic production of ink nozzles”: it provides not only high-quality, but also high-speed color photo printing.

The FINE print head uses a micro nozzle system: millions of microscopic ink droplets of a constant volume are applied to the paper every second with the highest precision. Unlike traditional inkjet technology, more ink is applied to the page in less time, which makes it possible to high speed print photos “edge-to-edge” (borderless) up to A4 format.

sublimation printing

The common disadvantage of all inkjet photo printers, caused by technological reasons - the banding of the print, which manifests itself in different models to varying degrees. At best, it is imperceptible or barely noticeable, however, if part of the nozzles become clogged or the printer mechanics fail, the print becomes divided into unattractive horizontal stripes. Sublimation printers belonging to the class of thermal printers are completely free from this drawback.

Sublimation printing technology comes from the Latin word sublimare ("lift up") and represents the transition of a substance when heated from a solid state to a gaseous state, bypassing the liquid state.

The principle of operation of a sublimation printer is as follows: when a print job is received, the printer heats the film with the dye applied to it, as a result of which the dye evaporates from the film and is applied to special paper. As a result of the same heating, the pores of the paper open and the dye is clearly fixed on the print, after which the surface of the paper again becomes smooth and glossy. Printing is carried out in several passes, since the three main dyes must be transferred to the paper in the correct combinations: magenta, cyan and yellow.

Since pixelation and banding are completely absent in this case due to the printing technology itself, sublimation printers working with a seemingly modest resolution of 300x300 dpi are capable of producing photographs that are not inferior in quality to prints of inkjet models with a much higher resolution. The main disadvantages of sublimation models are the high cost of consumables and the lack of household models that work with A4 sheets.

Conclusion

Which printer to choose, of course, you decide. For our part, we can suggest that a self-respecting inkjet photo printer works with a resolution of at least 4800x1200 dpi, sublimation - at least 300x300 dpi. Expendable materials inkjet photo printers are cheaper than sublimation ones, but the latter allow you to get a print with a quality much higher than inkjet ones. All modern sublimation photo printers for home printing are still compact models, and cannot boast of printing photos in A4 format, which is aimed at the vast majority of inkjet photo printers. Other than that, both are good.

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