Personal computer is a completely separate device, which is all that is necessary for an autonomous life. While talk of a "paperless" technologies are already under way for some time, the normal work with the computer is still difficult to use without a printing device. Often the need for paper copy of a document, image, etc., available in a computer file. There are printers primarily on the method of printing. Widely distributed several types of printers: the matrix, inkjet, laser, LED.
Matrix printer.
Matrix printers - the most common type of printer. The idea of matrix printers is that the desired image is reproduced from a set of specific points, inflicted on paper. In this type of printer used to print Printing heads (PG), which contains one or two rows of thin needles. The head mounted on rackets and moves along the printed line. At the same needles at the right time hit through the color tape and paper. This allows the formation of a paper symbols and images. In the low-cost models of printers used with PG 9 needles. Print quality is improving in these printers when printing information not one but two or four passes along the PG printed line. Better and fast printing provides 24-igolochnymi printers. However, these printers are more expensive compared to 9-igolochnymi less reliable.
To move krasyaschey tape used gear that uses the movement of the carriage. During the movement of the carriage to meet the stepping motor. Another step motor is responsible for the movement bumagoopornogo roller. Print speed matrix printers is low. Depending on the selected print quality and printer print speed ranges from 10 to 60 seconds per page.
Inkjet printer.
Method jet printing is now almost a hundred years. Lord Raleigh, a Nobel laureate in physics, made his fundamental discoveries in the collapse of the jets and the formation of liquid droplets even in the last century, date of birth jet printing technology can be considered only in 1948. It was then that a Swedish firm Siemens Elema filed a patent application for a device that works as a galvanometer, but are not equipped with measuring the arrow, a dispenser in which the recorded measurement results.
And even now, after almost half a century, this Brilliantly simple printing system is used, for example, in medical devices. However, liquid oscilloscope able to print only curves, rather than text and graphics. This efficient scheme has been improved and a new inkjet printer that operates on the principle of continuous spraying dye or print at high pressure.
The developers took advantage of regularity, identified by Lord Raleigh: jet of liquid is seeking disintegrate into separate drops. Just a little fix a random process of disintegration jets, nakladyvaya through pezoelektricheskogo changes in the jet dye emitted under high pressure (up to 90 bar), high-pressure fluctuations.
In this way, can released to a million droplets per second. Their size depends on the geometry nozzles, dispensers and accounted for only a few microns, and the speed with which they Doletaj before the paper reaches 40 m / sec.
With its high speed drops allowed to use the surface with a powerful speed control humps and depending on the quality of the press to place them at a distance of 1-2 cm from the nozzle, spray. As a result, you can mark, for example on the shelf life of the product on cartons, bottles, cans, eggs or cables. This technology is not difficult to learn to print spots appearing to be uneven, and how to fray.
Since the early 70-ies unusually intensified research activity aimed at creating a system without the shortcomings inherent in printing systems under high pressure. The first solution specialists - printers heads with piezoelectric transducers emitting at the request of individual drops of dye.
Printers with piezoelectric
executive mechanisms.
The first application for registration of the invention of inkjet printing with piezoelectric executive mechanisms have been filed in 1970 and 1971. For several years, various companies and institutions conducting basic research, until finally, the company Siemens was unable to translate this principle into a form acceptable to the market. In 1977 he was shown the first inkjet printer with dozirovannym release of the dye. This printer is equipped with twelve nozzles, dispensers and printers almost silently at speeds of 270 characters per second, made the revolution even in professional circles.
Siemens as an electromechanical transducer using piezoelectric trubochku incorporated in the channel from litevoy resin .. All channels end plate with a calibrated orifice for spraying, located on the front side of the device. Transmission of electricity and dye is produced solely by fluctuations of pressure applied to the channel in accordance with the laws of acoustics. Fluctuations in reaching the end of the channel is shown there inversion phase, ie in this place rocking with low pressure and vice versa.
Pezoplastiny.
In early 1985, the company Epson introduced the first of its pezoplanarnyh inkjet printers.
Instead of piezoelectric trubochek, like Siemens, for printing heads Epson, made from the structured glass plates, strengthened small pezoplastinki. If they make an electrical voltage, the diameter of a little change, but this will be enough to sognulis together with a passive multi-layer glass substrate like a bimetallic plate that would create a channel dye is pushed in the same way as in print heads with pezotrubochkami.
In 1987, the company Dataproducts suggested another principle of pezoelektrikov for inkjet printing, based on the use of plate pezopreobrazovatelya. In subsequent years, this technique has remained relatively little known and not so much because of a design based on the converter, but because of the liquid wax ink to be applied in all inkjet printers from Epson plate pezopreobrazovatelem production
According to this method pezopreobrazovatel, a long flat plate (bar), is located behind a small vessel with dyes. If the impact on bar-voltage pulse length varies slightly, resulting in a surge of pressure inside the tank, which, in turn, pushed a drop of nozzle-spray.
Plate pezopreobazovateli combine the advantages of a flat or tubular systems treble dispersal and compact design. Today, the printing heads with pezolamelyami are betting firms such as Dataproduts, Tektronix and Epson.
In early 1994, Epson demonstrated pezotehnologiyu MACH (Multilayer Actuator Head - head with multi-actuators). Nevertheless, in the piezoelectric printing heads MACH-heads are used pezolameli. However, the company Epson was able to produce a series of nozzles pezolameli-dispensers in a single unit (Multilayer). Thus it was possible further reduce the size of printing heads, to deploy converters, feeds and dispensers nozzle-less distance and simultaneously reduce production costs.
Printers with thermal executive
mechanisms.
In 1985, caused a sensation Thinkjet company Hewlett-Packard - the first jet-puzyrkovy thermal. The method of bubble-jet termopechati for several years subdued market (number of thermal inkjet totaled 10 million)
What is this revolutionary technology? As often happens in such cases, achievement was the reduction of production costs. If the piezoelectric printing machinery accounted for with more or less difficult to collect from many individual parts, the bubble-jet printer heads, representing the crystal on silicon substrates, constructed by hundreds of thin-layer technology.
In the thin-layer technology applicable in principle the same production processes that were used in the manufacture of integrated circuits. Channels filing dye, nozzle-dispensers, actuators and tokopodvodyaschie tire arise in alternating layers on the substrate causing, for example, means ion-beam sputtering, and subsequent structuring of these layers.
Thus, upon the completion of the production of more than hundreds of steps on one substrate is a lot termopechatayuschih elements. All structures must be implemented to the nearest thousandth of a millimeter. In addition, the slightest contamination in the production leads to denial. For this reason, bubble-jet printers are manufactured items in clean rooms and the use of machines, typical for the semiconductor industry.
As head of bubble-jet termopechati made on the same principle as integrated circuits, leads to the idea of integrating the latest in printing chips. And the first step in this direction has made firm Canon, built-in printer heads of their transistor matrix printers. The example was followed by Canon Company Xerox, published in 1993, the model of bubble-jet printer head equipped 128 dispensers, and fully integrated series-parallel converters.
The operation of bubble-jet nozzle, spray:
First, a strong impulse voltage duration of 3-7 ms applied to the tiny heating element, which instantly nakalyaetsya to 500 grams. Celsius. On its surface temperature exceeds 300 grams. Celsius. Power of heating surface is so high that if you lengthen the duration of voltage pulse of only a few microseconds heating element might be destroyed instantly.
Immediately in a thin film over the heating elements are beginning to boil ink, and after 15 microseconds to the closure of steam bubble of high pressure (up to 10 bar). It is pushing a drop of ink from the nozzle, spray, with what speed drops to 10 m / s or more. After 40 microseconds bubble, combined with the atmosphere, again opadaet, but it will be 200 microseconds, while the new ink by the action of capillary forces will not suck from the shell.
From the beginning of bubble-jet printer heads were divided into two groups. The company Canon, inventor of the system preferred option Edlgeshooter. Almost simultaneously firm Hewlett-Packard has developed a type of head Sidechooter, which now produces and the company Olivetti.
The head Edgeshooter, as is clear already from the title, spray ink droplets "a corner", ie perpendicular to the direction of education bubbles. As head Sideshooter, where the plate with nozzles, dispensers are on top of heating elements and channels feed ink, bubbles and drops moving in one direction. Because the edge of nozzle-type dispensers in the head Sideshooter made of homogeneous, rather than from different materials, as in Edgeshooter, the process of manufacturing dispensers with openings of a certain size to Sideshooter much easier than for heads Edgeshooter. In addition, it must take into account the different damping varied surface of the head Edgeshooter.
Quality requirements for any system of ink jet termopechati very high, much higher than pezosistemah. The principle of operation and high temperatures make use of only mixed soluble dyes in the water.
Dyes must comply with a number of requirements:
- To work together with the materials from which a printing mechanism;
- Do not form sediments in the canals and dispensers, and does not flake;
- Stored for a long time;
- Have certain performance density, viscosity and surface tension at temperatures from 10 to 40 grams. Celsius;
- Well serve as a breeding ground for bacteria and algae education;
- Do not contain toxic or carcinogenic substances and did not ignite.
By the same colors for jet termopechati should form bubbles of steam without sediment deposits and short-term withstand heat up to 350 grams. Celsius.
And so we see that the way inkjet printing, which had originated about 50 years ago - a relatively young technology. It is likely that inkjet printers win mass market, thus displacing matrix printers. If the developers will be able to improve the resolution and printing speed of inkjet printers, the manufacturer of laser printers will have to seriously fight for a place in the market.
So far, no other method of printing does not pose such a diversity of options, such as jet printing, with what is beyond doubt that the ability of this technology for a long time will not be exhausted.
Laser printers
Laser printers, and fax machines use the principle of dry xerography, which is based on the powder coating material, followed by fried.
How then arranged an ordinary laser printer? But before the move directly to printers consider first copy machines, since their buildings were made of laser printers.
Functionally the unit consists of the following components (if not seen skaniruyuschuyu part):
1. Photoreceptor (drum)
2. Magnetic shaft
3. Rakelny knife
4. Korotron charge
5. Val transfer (korotron transfer)
6. Korotron clipping
7. Bunker with toner
8. Bunker deep
9. Stove (fyuzer)
Photoreceptor is a special material (usually selenium), caused by the metal framework. Usually it is done in a shaft, so sometimes it is called drum (drum unit).
Photoreceptor charged korotronom charge, which is a metal (usually gold or platinum wire) or a rubber roller with a metal base. And rubber tokoprovodyaschaya. On older vehicles used wire korotron. There is a shift to other technologies. The fact is that the wire korotron heavily ozoniruet air from the high voltage to be applied to him. As you know ozone is useful, but in small quantities. Therefore, the characteristic odor of ozone in the copy center slowly back and forth.
After charging to the photoreceptor fed the image that in copiers highlights a powerful source of light and projected through a system of mirrors. Usually used to illuminate the original carriage with a lamp in the scanner, to increase or decrease the image is a lens with variable focal length. The speed of the drum and feed should be aligned. Those seats on the photoreceptor, which drops the light of changing its potential or even lose their charge (depending on the type of copy machine). Thus on the photoreceptor remains the original picture in the form of charged sites.
Then the photoreceptor is in contact with a magnetic shaft, which is covered with a mixture of toner and media.
Toner is a dust composed of fine particles particular color. To achieve a higher quality print manufacturers eager to build more small particles of toner.
Media (developer) represents the iron particles, which is deposited toner. Thus on a magnetic shaft are iron particles coated with toner. In some vehicles vehicle separated from the toner and zapravlyaetsya separately, in other toner is a powder has been mixed with a carrier. Toner is in a special bunker. Inside the bunker installed mixer, which prevents spressovyvanie toner.
Toner is transferred to the photoreceptor from the opposite charge on the photoreceptor. The whole process is called developer.
During this process, paper submitted for registration. Ie She is selected from the tray and placed in such a way as to start printing. When the sensor registration paper said that the paper came to the photo drum happening with the photo image transfer drum to the paper.
After the toner moved fed paper. Under the paper passes korotron transfer (Val transfer), which has a capacity greater capacity photoreceptor. This shaft is made of metal covered with a special conducting rubber. A shaft by a stronger capacity for it has delayed a toner, which is deposited on paper. Then, using a special mechanism paper torn off of receptor-fried and served on.