Printing technologies and printing devices. Computer device. What does computer consist of? Impact printing technology

In a modern office, almost all tasks related to the accumulation, storage and processing of a wide variety of information are performed using computers. However, whether we like it or not, it is still impossible to switch to a fully electronic document management due to a number of different reasons, and it is unlikely to succeed in the near future. That is why a modern office computer cannot be imagined without input-output devices.

Scanners

Scanners are the eyes of a computer that convert analog images (drawings, photographs, typewritten text, etc.) into one or another electronic format for subsequent storage and processing using various software tools.

Scanners are divided into several types depending on how the media is loaded. The most common at present are flatbed scanners: the document to be scanned is placed face down on a flat glass plate (usually it is closed on top with a special cover), under which there is a movable carriage with a light source, an optical system and a line of photosensitive elements. During scanning, the carriage moves along an axis parallel to the long side of the flatbed and reads the image line by line from the media placed on the flatbed.

The current popularity of flatbed scanners is fully justified, since they are the most versatile devices that allow you to scan individual sheets, pages of books and magazines without stitching, and with certain skills - even small volumetric objects. At the same time, they are easy to handle and do not require regular maintenance.

Sliding scanners are arranged somewhat differently: in them, the light source, the optical system and the line of photosensitive elements remain motionless during the scanning process, and the carrier is pulled through the scanning unit using a system of shafts and rollers. Currently, such devices are used mainly for scanning large format media - A3 and more. The main scope of their application is the input of various drawings, diagrams, maps and similar large-format documents for CAD and GIS systems.

Traverse scanners are not as versatile as flatbed scanners, because they allow you to work with media only in the form of rolls or individual sheets; however, there are restrictions on the maximum and minimum thickness of the carriers.

Previously, handheld and projection scanners were also common, but with the development of technology, the former were replaced by cheap flatbed models, and the latter gave way to more compact and convenient digital cameras. It is worth noting that after leaving the mass market, hand-held scanners have retained a rather specific niche: they are now quite widely used to read bar codes in automated point-of-sale terminals and other similar systems.

Consider the most important characteristics of scanners that you need to pay attention to when choosing the right model.

Resolution is measured in pixels per inch (ppi), and the larger this value, the more detail you can digitize the original images. Manufacturers usually indicate two resolution values: optical and interpolated (for example, 600 and 19,200 ppi), but in fact, it is the first parameter that characterizes the scanner's capabilities.

Another marketing ploy that is quite common among manufacturers is the indication of different optical resolutions for the vertical and horizontal axes, for example, 1200 × 600 ppi. However, one should not deceive oneself in this case, since the real value of the resolution corresponds to the smaller of the given values. Generally speaking, the pursuit of high resolution in the context of choosing an office scanner is hardly justified, since scanning opaque originals in reflected light with a resolution of more than 600 ppi is impractical. The fact is that, for a number of reasons, the detail of the resulting image will increase very slightly, but the file size will be very noticeable. Perhaps one of the few exceptions to this rule is the scanning of color printed originals: using a higher resolution will better cope with the characteristic moiré that inevitably occurs in this case.

As an example, here are the resolutions needed to perform some of the most typical office tasks:

optical text recognition - 300-400 ppi;
copying color and black and white documents - 200-600 ppi;
input of photos and drawings for posting on Web sites, in electronic documents and presentations - 75-150 ppi;
input of photographs and drawings for reproduction on monochrome and color printers - 200-400 ppi.

The number of shades reproduced during scanning is determined by the bit depth, measured in bits per color channel. For color scanners, the sum of the three color channels is often given. For example, the inscription "24 bits" means that for each of the three color channels - red, blue and green - the bit depth is 8 bits per color; the maximum possible number of shades is about 16.7 million. A typical value for this parameter is 8 bits per color channel (24 bits RGB), and many models of modern flatbed scanners allow you to digitize an image with a bit depth of 12, 14 and even 16 bits per color channel (respectively 36, 42 and 48 bit RGB). It must be said that for office applications, increasing the bit depth does not make practical sense, since office applications, as a rule, do not allow processing and placing images with a bit depth of more than 8 bits per color channel in documents. Some time ago, you could still find black and white scanners, but today the vast majority of models allow you to scan in color.

The maximum size of originals that can be scanned for flatbed scanners is determined by the size of the flatbed; the most typical value is 216x297mm (it can scan documents of the most common A4 size), although sometimes there are models with an extended flatbed (216x356mm). A3 flatbed scanners (297×420 mm) are quite expensive and usually belong to the professional class. As for draw models, the situation here is somewhat different: if the maximum media width is determined by the physical parameters of the device (the width of the feed path), then the limit on the allowable length is imposed by the driver and the software used.

With a heavy load on the scanner, its performance becomes very critical, which depends on the scanning speed. It is worth noting that this parameter even for the same model varies depending on the resolution: the higher the resolution specified in the settings, the slower the scanner works. In addition, the overall performance of the scanner is affected by the pre-scan speed and warm-up time. It should also be taken into account that when setting high resolution values, the bottleneck may not be the scanner itself, but the interface used to connect it.

For some flatbed scanner models, Auto Document Feeders (ADF) are available, which may be included as standard or sold separately. The use of such a device (which is usually installed instead of the standard tablet cover) allows you to increase the productivity of the scanner when entering a large number of originals of the same type on separate sheets, for example, ready-made forms (questionnaires, questionnaires), voluminous typewritten texts, etc.

Today, the most common interface for connecting scanners is USB 1.1. Recently, expensive models of flatbed scanners are equipped with higher-speed interfaces - USB 2.0 and IEEE-1394. Unlike USB 1.1, USB 2.0 and IEEE-1394 controllers are still rarely found as standard in office computers, so connecting scanners with these interfaces will most likely require the installation of an appropriate board.

Among the oldest and cheapest scanners, you can still find models equipped with SCSI and even a parallel IEEE-1284 interface, however, in modern conditions, the acquisition of such devices can hardly be considered expedient.

Printer types

The undisputed leader among office printers today are A4 and A3 monochrome laser printers. They have high productivity, low cost of prints and are able to withstand heavy loads. Another advantage is the consistently high quality of prints, almost independent of the type of paper used.

Recently, there has been an increase in the popularity of color laser printers. A few years ago, these were very expensive and low-performance devices (due to the use of a four-pass process, the print speed in color mode was much lower than in monochrome), but today the prices for color laser models have dropped significantly, and many manufacturers have mastered the production of devices that allow print both monochrome and color images equally quickly.

In many ways, LED printers are similar to laser printers. Due to the use of a simplified (compared to laser) imaging technology, these devices are cheaper than laser ones; however, at the same time they are inferior to the latter in terms of the quality of the resulting prints and performance. Now many manufacturers produce both monochrome and color LED printers.

Currently, the market offers a very wide range of models of laser and LED printers - from desktop personal to network corporate. As a rule, small desktop models have minimal configuration expansion options and are usually used in small departments for this reason. If we talk about laser and LED printers at the level of medium and large workgroups, then almost all of them are a kind of constructor: the required number of different functional modules (additional trays for supplying various media, sorters, booklet makers, finishers, etc.). In addition, there are opportunities to expand the configuration of the base device by installing additional components (memory modules, hard drives, font cartridges, network adapters and print servers, page description language interpreters, automatic two-sided printing modules, etc.). Thanks to this, it is quite easy to change the set of functionality of the printing device, depending on the needs of the department in which it is used.

Inkjet models are also quite widespread in offices, the vast majority of which are colored. Their use is justified in cases where there is a need for color documents, and the average monthly print volumes are small. It should be noted that if the cost of inkjet printers themselves is much lower than laser or LED, then the cost of consumables and, consequently, the cost of a copy is much higher. I would like to draw attention to the fact that three or four years ago, offices used mainly personal models of inkjet printers (since there were practically no others), and today a separate class of corporate inkjet printers specially oriented to office tasks has already emerged and is actively developing. . They are distinguished from personal models by higher productivity, the use of high-capacity cartridges, a long service life and the maximum allowable monthly load, as well as a lower dependence of the quality of the resulting images on the type of paper used.

Large-format inkjet printers stand somewhat apart, however, since they are used to solve quite specific tasks, we will not consider them in this article.

Despite the fact that today dot matrix printers have almost completely lost their positions in the market for personal printing devices, they are still produced and actively used in various organizations. Of course, matrix devices cannot boast of high performance and low noise levels, but thanks to a simple device, they are distinguished by very high reliability and extremely low cost of prints. But the secret of their longevity lies not in this, but in the fact that these are the only percussion printers that are widely used today (in addition to the dye dots, a relief mark remains on the paper), and the specifics of the activities of a number of companies require the use of just such printers when filling out official documents and forms. (for example, rail and air tickets).

It is impossible not to mention the rather exotic devices that are relatively rare in offices - thermal printers. The most famous representatives of thermal printers using solid dye thermal transfer technology are the devices of the American company ALPS and their OEM versions, also produced under the brands Citizen Printiva and OKI. These devices have a rather low printing speed and a very high cost of copies, but they also have a number of undeniable advantages: the use of a solid dye provides a very high resistance of prints to mechanical and chemical stress, and the resulting image is practically independent of the type and quality of the media coating. In addition, when using special media, printed images can be transferred to fabric and to the surface of various objects. It is also worth noting that cassettes with dyes of non-standard colors (for example, white, green, silver, bronze, gold, etc.) are produced for these printers. One of the most typical applications of thermal printers is the production of small runs of souvenir and representative (business cards, forms, invitations, etc.) products.

There are also specialized thermal printers designed for printing images on the surface of CDs. Examples include the Inscripta printers from Primera Technology Corporation and the Perfect Image Prism printers from Rimage Corporation. Such devices can be a good solution for departments whose activities are related to the distribution of various products and information materials on CD and DVD media.

Now that we have familiarized ourselves with the main types of printing devices common today, let's move on to reviewing the main characteristics of printers.

Main characteristics of printers

Resolution is measured in dots per inch (dpi). The larger this setting, the more accurately the printer can reproduce output images: when printing text and monochrome drawings, this means higher image detail, and for grayscale images, the ability to transfer more shades with the same lineature. A resolution of 300-600 dpi is sufficient for printing text documents, while a resolution of 720 dpi or more is required for high-quality output of grayscale and color images.

Currently, manufacturers use various technologies in their products to increase the number of reproduced halftones without increasing the resolution. In addition, it is worth noting that in practice, printers from different manufacturers with the same resolution do not always provide the same quality images.

Printer performance is determined by several parameters: warm-up time, screening speed, and the speed of the printing mechanism. The warm-up time depends on the printing technology used: if inkjet and dot matrix printers are ready for use almost immediately after being turned on, then laser and thermal printers take a certain time (from several seconds to several minutes) to enter the operating mode.

Depending on the design of a particular device, screening of the printed image can be performed both by the driver (which is typical for most inkjet and matrix devices, as well as entry-level laser printers), and by a specialized processor of the printer itself (this solution is usually used in medium and large laser and in some inkjet models). In the first case, the rasterization time is largely determined by the configuration of the computer from which the document is sent for printing. Other things being equal, the rasterization time depends on the resolution set in the print settings: doubling the resolution value will quadruple the size of the raster image of the page, which will significantly increase the time required to process the document and send it to the printer.

Printer manufacturers in the technical specifications of their products usually indicate only two parameters: the maximum speed of the printing mechanism and the first page out time after sending the document to print. However, it should be borne in mind that, unlike laser and LED printers, the speed of operation of the printing mechanisms of inkjet, matrix and some thermal devices significantly depends on the set resolution and page coverage; thus, the actual figures for these printers may be significantly lower than those declared by the manufacturer.

Media requirements typically include a list of media types suitable for a particular device (plain paper, specialty papers, envelopes, postcards, labels, cards, transparencies, etc.) and the acceptable weight range, or specific gravity, for each type of media (usually indicated in grams per square meter, g/m 2; in addition, a limit on the maximum thickness of media is sometimes indicated). Please note that these settings may vary depending on the feeding method (manual or automatic) and the use of various options (auto duplex unit, booklet maker, etc.).

The capacity of the input and output trays is specified in the printer specifications. Most often, this parameter is calculated for sheets of plain paper with a density of 60 or 75 g / m 2.

Speaking about an office printer, one cannot fail to mention the integration of this device into a local network. Various solutions can be used for this, the most common of which is to install a special network adapter or print server in the printer. Naturally, when choosing a printing device, it is necessary to clarify whether the range of network adapters and print servers offered by the printer manufacturer has modules that are compatible with the projected or existing local network of the enterprise or division.

Optimizing Printer Usage

Any system administrator working in a more or less large office is well aware that the load on printers is extremely uneven - periods of temporary calm are suddenly replaced by spontaneous bursts of employee activity, and even high-performance network printers can not always cope with an avalanche of documents falling on them. Here is the most typical situation: one of the users sent a report of several hundred pages to print - as a result, other employees have to wait until their one-two-page letters and invoices are printed.

It is quite obvious that the purchase of additional printers is unlikely to effectively deal with such situations and, moreover, will entail additional financial costs. But it turns out that you can get by with the existing fleet of printers if you increase the efficiency of their use.

The essence of the solution is as follows: the printers available to this unit are combined into a cluster, the operation of which is controlled by a common print server. Using this scheme provides a number of advantages over the more traditional connection of individual network printers.

One of the most illustrative examples is the parallelization of printing when outputting large documents or a large number of copies. This is implemented as follows: when the minimum number of pages specified in the settings is exceeded, the document sent for printing is divided into several parts, which are printed in parallel on different cluster printers (the user who sent the task will receive a notification on which devices the parts of the document were printed on). This allows not only to reduce the time for obtaining a finished document, but also to evenly distribute the load between the devices included in the cluster. In addition, the cluster controller can redirect jobs in case of failures: for example, if any of the printers runs out of toner or paper jams, all jobs sent to it will be redirected to another device, and users will receive appropriate notifications.

It must be said that from the user's point of view, the printing procedure also becomes simpler: instead of several different printers, the menu remains one universal printing device, to which all tasks are sent, and the choice of the most suitable printer for printing a specific document is controlled by the cluster controller.

Examples of cluster printing solutions include JetCAPS ClusterQue (a joint development between Hewlett-Packard and LBM Systems) and Callisto (a Canon development).

Multifunction devices

it is false to say which of the developers first came up with the idea to combine the printer and scanner into a single device. Yes, it is, in general, and it does not matter. The benefits of such a symbiosis are obvious: the user receives one device that can perform the functions of three different devices at once - a scanner, a printer and a copier, and if you add a fax module, then four. Of course, this solution is cheaper than three or four separate devices and requires much less space. True, some disadvantage in this case is lower reliability: for example, if the power supply fails, you will simultaneously lose the ability to use all devices at once, and if you run out of toner or ink in the printing module, you will not be able to use not only the printer, but also the copier.

Be that as it may, for several years multifunctional devices have been in steady demand, and manufacturers regularly update the lineup of these office combines. Currently, there is a fairly clear division of multifunctional devices into two large groups: compact desktop devices and large corporate complexes.

Multifunctional desktop devices are distinguished by a variety of appearance and technical solutions. On sale you can find multifunctional devices built on the basis of both broaching and flatbed scanning modules. If we talk about the printer part, then it can be an inkjet (color or monochrome) and a laser (usually monochrome) printer. Typically, such devices provide the ability to connect to a computer via a bidirectional parallel interface IEEE-1284 and / or USB.

As for corporate multifunctional complexes, they are often high-performance digital copiers equipped with a computer interface. Typically, they are equipped with a laser printing mechanism (color or monochrome) and a flatbed (less often - traction) scanner module with an automatic document feeder. Similar to corporate laser printers, many multifunctional systems can be expanded by installing additional components and external functional modules.

ComputerPress 9 "2002

The printing device provides the output of data that is electronically stored in its memory of the computer on paper or other media. A characteristic feature that allows such devices to be classified is the method of printing or the technology by which the image is applied to the carrier.

Inkjet Technology

With the use of this technology, the image is transferred by means of a drip or string supply of dye. The picture is transferred to a paper medium of any quality, you just have to buy a 3D printer in the Tsvetnoy Mir store.

Impact printing technology

This is a method of transferring an image to any type of media by hitting the ink ribbon with one letter or a whole set of needles. The advantages of this technology include the ability to transfer images to media with any quality and texture of paper. Of the shortcomings, the most important is the rather high noise effect during its operation at a rather low print speed. Printers in this category are divided into two groups - matrix and printers with the presence of font media in the print head.

Thermoelectric printing technology

This type of printing can be done only by applying an image to a special medium - a special type of paper, in the structure of which changes occur under the influence of heat. At the heating point, such paper darkens, due to which the required image is formed on it. The print head of a thermoelectric printer in its design contains from one to several heating elements.

The main disadvantage of a thermal printer is the ability to use only one type of paper. Therefore, the scope of these printing devices is quite narrow, they are needed, for example, as additional equipment for a fax machine.

Printer with font media

The print head of the printer, equipped with font carriers, transfers the graphic image to the carrier by hitting a certain set of characters on the ink ribbon. The main advantage of this type of printer is that it prints at high speed with an image quality that is very similar to printing. A significant disadvantage of this type of printing device is the presence of a factor limiting their dynamic development of such printers, which occurs when it is necessary to change the font and print the necessary graphic data.

Dot Order Printer

Obtaining an image on paper or on other media by means of a dot matrix printer is performed by hitting the ink ribbon with a special set of needles. They can be arranged in a row or like a rectangle, performing their function by analogy with the print head. The picture is transferred to the media in dots, while in the print head one head corresponding to a specific point is pulled out, hitting the ink ribbon. The movement of the head itself during printing occurs along the line.

Matrix-type printers have found wide application, since they are quite unpretentious in operation and maintenance, consumables for them are affordable. Also, such devices are capable of transferring an image to a paper medium of any quality, they are characterized by reliability and a high degree of performance.

A dot matrix printer is indispensable when the requirements for the quality of the printed material are minimal and in cases where printing is technically impossible on other types of printers. Its main advantage is the simultaneous printing of a picture in several copies.

Scanners

Consider the most important characteristics of scanners that you need to pay attention to when choosing the right model.

As an example, here are the resolutions needed to perform some of the most typical office tasks:

optical text recognition - 300-400 ppi;
copying color and black and white documents - 200-600 ppi;
input of photos and drawings for posting on Web sites, in electronic documents and presentations - 75-150 ppi;
input of photographs and drawings for reproduction on monochrome and color printers - 200-400 ppi.

Printer types

Large-format inkjet printers stand somewhat apart, however, since they are used to solve quite specific tasks, we will not consider them in this article.

Now that we have familiarized ourselves with the main types of printing devices common today, let's move on to reviewing the main characteristics of printers.

Main characteristics of printers

The capacity of the input and output trays is specified in the printer specifications. Most often, this parameter is calculated for sheets of plain paper with a density of 60 or 75 g / m 2.

Optimizing Printer Usage

Examples of cluster printing solutions include JetCAPS ClusterQue (a joint development between Hewlett-Packard and LBM Systems) and Callisto (a Canon development).

Multifunction devices

ComputerPress 9 "2002

Now you almost never see documents written by hand. Everyone and everywhere requires documents with printed type. Since typewriters are no longer relevant, they have been replaced by a personal computer as a typing device and a printer as a device for outputting electronic information to paper.

The printer has now become so widespread that the price of the simplest does not exceed 600 rubles. And if in firms specialists are engaged in the purchase of this equipment, then everyone chooses a printer for personal use, as a result of which no one is immune from a purchase that can spoil a lot of nerves.

Recently, at home, it is still more common to find not pure printers, but multifunctional devices (MFPs) that combine the functions of a scanner, copier and printer. But you need to choose these devices based on their capabilities and printing technologies, since their scanner characteristics are almost the same. That is why in this material we will operate only with the concept of "printer" or "printing device", but keep in mind that all the information below is equally applicable to the MFP.

PRINT TECHNOLOGIES

The main criterion by which printing devices are divided can be called the principle of printing that they use. The most common are: inkjet technology, laser, matrix and sublimation. From what printing technology is used in certain devices, their functionality and cost, as well as the types of consumables used, directly depend.

inkjet printing

Inkjet printers are based on the technology of spraying ink droplets onto paper. Ink injection occurs through special holes - nozzles (nozzles). The more holes, the better the print quality. The ink from the nozzles is injected either with the help of a thermal element, as a result of which steam is generated, which pushes the ink onto the paper (HP, Canon), or with the help of a piezoelectric element (Epson), which changes the diameter of the nozzles due to an electric discharge.

For full-color printing in this type of device, several cartridges (ink) of different colors are responsible, and their number varies depending on the model. The cheapest devices use four-color printing (black, red, green, blue), but in expensive ones, the number of colors can be up to eight. At the same time, to obtain a more realistic print, not “pure” colors are used, but their shades (pink, turquoise, crimson, etc.).

The main advantages of inkjet printers are the low cost of devices and high print quality, especially images. Therefore, if you plan to use the printer more for printing photos, then this is your choice. True, high-quality printing of images is possible only on specialized photo paper.

The disadvantages of this printing technology is the high cost of consumables. Sometimes a cartridge can cost more than 50% of the entire printer. In addition, the reliability of "inkjet" leaves much to be desired - due to the small size of the nozzles, they are often clogged with dust or dried ink, which leads to a sharp deterioration in print quality. Most often this is expressed in the fact that the printer begins to streak due to incorrect color mixing.

Despite the fact that almost every inkjet printer software has a built-in nozzle cleaning utility, its use does not always bring positive results. In this case, the solution to this common problem will directly depend on what type of cartridge is used in the printing device, and this fact should be taken into account when choosing a printer.

Typically, two types of cartridges are used for inkjet printing. Some manufacturers combine them with the print head (for example, HP) and then it is enough to simply replace the cartridge to restore print quality. True, the use of this approach leads to an increase in the cost of consumables, which are already expensive in this technology.

Cartridges integrated with the print head

Another type are ink cartridges, where the print head is a separate independent device inside the printer. In this case, the print head can be either removable (Canon) or not (Epson).

Ink cartridges installed in the print head

A removable print head, in case of problems, is enough to be placed in a special solution that will clean the clogged nozzles, but in the case of a fixed head, you will most likely have to contact a service center. At the same time, the cost of its repair or replacement can reach 70% of the cost of a new printer.

In general, all these troubles with nozzles arise when the printer has been idle for quite a long time and in order to avoid them, it is enough to regularly (at least once every few weeks) produce full-color printing of small images that do not consume a lot of precious ink.

laser printing

An alternative to inkjet printers are printers with a laser print head. Laser printers are by far the most common in the corporate sector and have recently been increasingly used in the home.

This is facilitated by several indisputable advantages of this technology:

Higher reliability than inkjet printers. The ink in this technology is not liquid and therefore there are no problems with their drying.
Excellent monochrome print quality (especially texts) without the use of specialized paper
Large resource of cartridges
Inexpensive service

Printing technology is fundamentally different from the technology of inkjet printers. The laser, through special lenses and mirrors, illuminates the surface of the photodrum, which has the property of discretely, that is, at different points in different ways to leave an electric charge. After that, the illuminated part, rotating, comes into contact with the toner, and at the same time, the toner falls off from the illuminated parts, but there are no illuminated parts, and the toner sticks to the unexposed areas. After that, the drum “rolls over the sheet of paper and the toner is transferred from the drum to the sheet. The sheet then passes through an oven where the toner is finally cured.

Most laser printers are monochrome oriented and therefore use a single black toner cartridge. Color printers use four cartridges (black, cyan, yellow, and magenta).

But this technology is not without its downsides. The first and most important is the high price of (especially color) printers. And the second - the worst quality of printing images, and the lack of the ability to print photos.

If you need a printer to print a large number of text documents, without compromising the quality of color images, then this is your choice.

Dot matrix printing

Dot matrix printers are not used as a home printing device, due to the fact that this technology has long been outdated. The principle of printing these printers is similar to the principle of a typewriter. The matrix, with a set of needles in the amount of 9,18 or 24, moves, under the matrix there is an ink ribbon, and under the ribbon there is a sheet of paper. With the help of electromagnets, the needles hit the tape, and the blueberries from the tape in the form of dots remain on the paper. Although this technology is outdated, dot matrix printers are still in use.

The fact is that almost every dot matrix printer prints an image in its own way, so dot matrix printers are used in the manufacture of important papers. In addition, it will not be possible to reduce the ink from the paper. Dot matrix printers can often be found in banks.

The main advantages of matrix technology are:

Possibility of multi-layer printing, as a carbon copy
High document security
Ease of printing on long media such as ribbons

The main disadvantage is the poor quality of printing texts, and especially images.

sublimation printing

Sublimation printers are most widely used in the professional field and are used to apply images to fabrics, awnings, plastic, aluminum, tiles and other non-paper materials, although printing on paper is of course also possible. The principle of printing is based on the evaporation of the dye. First, the print head warms up, then begins to move over the surface on which the dye is applied, when heated, the dye evaporates and settles on the surface to be painted.

Full color printing is achieved by mixing three colors - cyan, magenta and yellow and is carried out in three passes, since the colors are applied to the material in turn.

The advantages of this technology include the high resistance of the image to sunlight and moisture due to the fact that the ink is hard and penetrates deeply into the structure of the printed material. In this case, the images are of very high quality, due to smooth color transitions and the ability to mix colors in a wide range.

The main disadvantage is the high price of devices and consumables, which greatly limits their distribution and use at home.

QUALITY AND SPEED OF PRINTING

The next important characteristics of printers are the speed and quality of printing. Print quality directly depends on the number of dots per inch applied by the printing device to the material. The higher this figure, the better print you can get. For inkjet printers, 1200 dots per inch (dpi) or higher is considered acceptable. For lasers, this threshold is lower - 600 dpi is considered normal print quality. Printing images and photos requires higher resolutions, at least 2400 dpi.

The print speed of printers is measured in the number of pages they print per minute. Almost all modern printers have fairly high speeds. Still, laser technology shows the most impressive results, and the print speed of such devices does not depend on the set resolution. For inkjet printers, one should take into account the fact that manufacturers, as a rule, indicate the print speed in the worst quality and when printing at normal resolution, it will be much less than indicated.

PRINT FORMATS

Most printers are A4 format, i.e. the maximum sheet size on which it can print is 21 cm wide and 29.7 cm high (regular sheet of paper). For the convenience of printing smaller sizes (photos, envelopes), many devices have an adjustable paper feed tray or additional feed trays. If you need to print on larger A3 sheets (29.7 cm x 42 cm), you will have to choose a large format printer, which will cost much more. There are also more highly specialized printers that can print on A0 roll paper.

CONSUMABLES

Consumables include cartridges, ink, toners, and in the case of dot matrix printers, and ink ribbon. Also, they include various specialized paper, for example, for printing photos or stickers.

When choosing a printing device, it is appropriate to clarify the cost of new cartridges for it, their capacity and the possibility of refilling. At the moment, many laser and inkjet printer cartridges are refilled after they run out of ink or toner. However, some of them even after several refueling retain acceptable print quality. Of course, manufacturers of consumables do not welcome this approach, but this allows users to save a lot of money. After all, refilling a cartridge is much cheaper than buying a new one.

Also keep in mind that when buying a new printer, it comes with cartridges refilled at 30, 50 or 60%. That is why they end much faster than bought separately. True, if later such a cartridge can be refilled, then its resource will not differ from others in any way.

Before buying, be sure to weigh all the costs of consumables - sometimes it is better to pay for a more expensive printer, which will more than pay off with cheaper maintenance.

CONNECTION TYPES

In modern printers, the main connection interface is USB. But you can still find printers that support the old LPT standard. For office solutions, where the device can be used by several users at once, there are printers with a wired (LAN) or wireless (Wi-Fi) network interface.

MULTIFUNCTIONAL DEVICES

Now the so-called MFPs or multifunctional devices have gained particular popularity.

Typically, these devices combine the functions of a printer, scanner and copier. The latter is a device resulting from a combination of a printer and a scanner. It is intended for obtaining copies of documents, drawings, photographs and other images from one sheet to another, without the participation of a computer. In the people, often, the copier is called a copier, but this name is erroneous and incorrect. In some MFPs, primarily designed for offices, a fax device may also be added.

CONCLUSION

Now let's briefly summarize. For home use, we would recommend using a laser printer or MFP. An inkjet printer is also suitable for the home as a budget option, or if the print quality of a multifunctional device does not suit you. It is not advisable to purchase dot-matrix and sublimation printers for the home. When buying, you should clarify the cost of consumables and service for the device you have chosen.

On this page, we will talk about topics such as: Printing devices, Dot matrix printers, inkjet printing, Print technology, Laser printer and about everything connected with it.

Computer a printer, or simply a printer(from English Print - "print") - a printing device for obtaining a "hard copy" (printing on various types of media, mainly paper) of texts, images, graphics - i.e. documents initially stored in a digital form understandable to a computer and other information processing devices.

Note

Initially, a computer printer meant a peripheral device connected to a PC via one of the widely used interfaces (including wireless or network) ...

This definition is now somewhat outdated. Since, firstly, there are many ways to output data to a printer without the "mediation" of a computer - for example, directly from Flash cards, digital video and photo cameras, built-in fax modems. Secondly, a fairly common class of MFPs has appeared, which are a combination of input devices, plus a built-in “mini-computer” for prepress data processing.

MFP- multifunction device. In relation to devices for creating a "hard copy" of documents, this abbreviation, as a rule, means a printer, structurally, logically and programmatically integrated with one or more data processing devices and auxiliary solutions.

Classical MFP- it a printer, combined with a scanner, resulting in a device for printing, scanning and copying in one housing. The addition of a fax modem card and telephone line interface turns this device into an office device. MFP with fax processing function. Modern MFPs, as a rule, are universal - they have several interfaces at once, slots for Flash cards, built-in memory for storing data, etc.

Print technology.

laser printing- conditional general simplified name of electrographic dry printing systems, when the raster of the printed page prepared by the processor is applied to the photosensitive drum laser or a similar light source, then, using static electricity (due to the potential difference), the special toner is transferred to the drum. Next, the toner is transferred to a paper carrier, where it is subsequently fixed (fixed) using heat, sometimes additional pressure.

Usually, laser printer slightly more expensive than inkjet models with similar performance, but due to the high capacity of a typical toner cartridge and a number of other parameters such as high speed, durability, low cost per print (especially in the case of a monochrome laser printer) it is more preferable for office use for printing documents .
Laser printers come in both monochrome and color.

Variety laser printers can be considered light-emitting diode (LED) printers. LED and laser digital printing technologies are similar to the use of electrography, however, if in the first case a laser unit is used as a light source to form a surface charge on a photosensitive drum or tape, then in an LED printer there is a line (or several - if we are talking about a color model) of thousands of LEDs, through focusing lenses illuminating the surface of the photosensitive drum / tape at once across the entire width.

Inkjet printing.

inkjet printing – printing technology, in which the imprint on the media is formed by ink drops "shooting" from the nozzles of the print head. As a rule, the size of ink drops of modern printers measured in units of picoliters (10-12, one trillionth of a liter), respectively, the print resolution with this method of imprint formation is thousands of dots per inch.

Printheads of modern inkjet printers With tens to hundreds of nozzles, the matrix nozzle arrangement increases print speed and better color blending of miniature ink droplets for more realistic results.

Typical jet printer is generally inexpensive to produce, other benefits include significantly higher quality photo printing than a typical laser printer.

The disadvantages of inkjet printing include the fact that often the cost printer comparable to the price of a new set of ink cartridges.

Inkjet printing is much more demanding on media, moreover, ink, in case of long periods of non-use printer tend to dry out, sometimes resulting in the need to replace the print head.

There are also inkjet photo printers- as a rule, models with a large number of different ink colors, up to ten, the ink of which reproduces the photorealistic color gamut better on special photographic paper for inkjet printing.

In general, modern inkjet printing significantly differs from the samples of a decade and even five years ago: the printing speed has been significantly increased, the cost of a print has been reduced, many issues have been resolved with the use of various types of media and ink drying.

Dot matrix printers.

Dot matrix printers use combinations of small pins that hit the ink ribbon, which leaves an imprint of the character on the paper. Each character printed on printer, is formed from a set of 9, 18 or 24 needles formed in the form of a vertical column. The disadvantages of these inexpensive printers are noisy and poor print quality.

Printing principle: printhead printer contains a vertical row of needles that are the cores of electromagnets. When a current pulse is applied to the winding of one or another magnet, the needle is pushed out of the winding and strikes the paper through the ink ribbon. These dots form the image.

Solid ink printing.

Solid ink printing- a technology for transferring molten wax ink through holes whose diameter is less than the thickness of a human hair, from stationary printheads to a rotating drum, from which the image is then transferred to the media.

The advantages of the technology are the reproduction of bright colors on almost any surface, excellent coverage of the RGB gamut by CMYK ink; simple design of the color printing mechanism that transfers solid ink in one pass of the media; high speed. There is also a drawback - high ink consumption during a "cold start" for preparation and calibration.

Sublimation printing.

Sublimation(Dye sublimation) printers in the process of forming a print, heating of special tapes is used, as a result of which the color dye is transferred to the carrier. Most common sublimation printers for working with one color - they are usually used to print on media such as plastic cards, paper or canvas. Color models are also common, where several ribbons with dyes of several colors are used for transfer.

Thermal printing, thermal transfer.

Thermal printing, thermal transfer- the principle of printing, which uses a special carrier that changes its color after heating. A typical example of such printer– fax on thermal paper, where the special media roller, after local heating, is capable of transmitting the “facsimile” character of the original.

This concludes this article, I hope you have fully understood the topics: Printing devices, Dot matrix printers, inkjet printing, printing technology,Laser printer.