Laser printer is a variationA computer printer that uses a laser beam to create an image. The image is created as an array of very small points. The use of laser in this case allows you to create very clear detailed images, text or photographic, the quality of which corresponds to the offset printing used for printing books and magazines.
Today, a huge number of models are produced.laser printers. In order not to get lost in this diversity, it is necessary to have clear guidelines. The main parameters of laser printers include print speed, resolution (image clarity), printer control language, internal memory size and paper size used. Since contactless printing technology is used in laser printers, they are very quiet, and many users consider the absence of noise to be an important criterion when buying a device for office use. Laser printers are simplex, i.e., they print only on one side of the paper, and duplex - print on both sides. They can print color images, but most of them are monochrome. Thus, the main parameters of laser printers include such parameters as noise level, the possibility of duplex printing and the ability to print color images.
Laser printers are available in widespeed range. The main parameters of laser printers are indicators such as speed in one-sided images per minute and in pages per minute. These speeds are equal for one-sided printers, and two-sided printers print two images on one sheet. Since a duplex is usually a one-sided printer that can turn the paper on the other side, the duplex printing speed in pages per minute is about half the speed of a simplex printer.
The parameter that manufacturers indicateprinting devices, is the highest speed that the printing mechanism is able to provide. When printing simple pages with a minimum of text or complex graphics, most devices will achieve the indicators declared by the manufacturer, however complex pages with a lot of text or complex graphics can load the controller so much (the processor that forms the data in the image) that a long processing time will not allow device to work at full speed. The consequence of this is that when printing complex pages, the actual print speed may not exceed 10% of the nominal.
The first color laser printers printeach color required a separate pass through the printing mechanism. Most color devices use four colors, magenta, cyan, black, and yellow, and can print in both color and black and white images. With color printing, they operate at a rate that is a quarter of the speed of their printing in monochrome. There are also color devices that create a full-color image in 1 pass.
Laser printers are generally classifiedby speed of work. Personal printers operate at speeds of up to about 20 ppm, office or desktop printers fall in the range of 20-40 ppm, workgroup printers - 40-60-, and large printing presses - up to 60 ppm and more. The speed of the fastest printers exceeds 200 ppm.
If you evaluate the main parameters of the laserprinters resolution is the most important indicator of their quality of work. The resolution corresponds to the number of individual points that it can print within a given area. Laser printers create an image using an array of dots called “bitmap images”. Modern laser printers achieve a resolution of 1200 points per square meter. inch. Since most devices have the same horizontal and vertical resolution, this measurement is usually reduced to "dots per inch" (d / d), which corresponds to the resolution on both the horizontal and vertical axes. Some of the latest models of laser printers have a resolution of 38400x600 dpi or 23,040,000 dots per square inch. Obviously, the higher this figure, the thinner and more detailed the image the printer can produce.
Manufacturers use other technologies.image enhancement. For example, Hewlett-Packard's ImageREt system changes the size and position of the dots that make up the text or image, which allows, for example, placing very small dots at the edge of a pixel, making the image clearer, with sharp, smooth contour lines. In addition, she:
- uses multi-level printing, thanks to which, to achieve the desired pixel hue, the printer prior to mixing, using complex algorithms, varies the amount of toner of each color;
- applies adaptive halftoning,using multi-level printing technology to smooth out the contours and even print large areas, increasing or decreasing the frequency of digital halftones by reducing or increasing the distance between them;
- uses color trapping - a patented technology of intentionally overlapping one color with another to improve image quality in transition areas;
- reduces halo - automatically removes one color from the edge of another, reducing the overlap zones and making them less visible;
- automatically conducts closed calibrationcolors by pre-printing the image onto an electrostatic tape and selecting the amount of toner that is needed for reliable and stable color transfer
Technologies that improve the basic parameters of laser printers are exclusive HP innovative technologies. At this time, several levels of ImageREt have been developed:
Language used in the printing deviceis a set of commands that it performs to format the data transmitted from the computer. These commands are embedded and interpreted by the printer. There are many control languages: some are specifically designed for laser printers, while others that were used earlier in simple devices are interpreted by some devices for compatibility with old software.
Control language refers to the main parameterslaser printers, as most computer applications support only a fraction of the variety of languages. IBM mainframes and minicomputers support management languages created by IBM. On Macintosh, most applications use Adobe PostScript, the industry standard language for describing complex pages.
Printer Management Languages are divided into twocategories. There are page description languages (PDL) and ESC sequence languages. The former are usually more versatile and complex and allow you to print more complex pages and graphics that are suitable for creating such high-quality products as presentation materials, technical instructions, catalogs, flyers, etc. The second is used by software packages that produce complex, highly formatted output, including in graphic design programs, word processors, spreadsheets with extensive graphing capabilities.
The main disadvantage of page description languagesis that they require significant computational resources, with the result that PDL printers format data more slowly. This is overcome by installing a more powerful printer controller, which affects the cost of the device.
Among the PDL languages stand out:
- PostScript - the language of the company Adobe Systems,originally used in Apple computers. Its advantage lies in the greater detail of the image and the independence of the print results from the printing device used, and the drawback is in the slowness, increased requirements for the amount of memory and the lack of support on many platforms.
- PCL - language created in the companyHewlett-Packard, the main difference is the use of printer resources for imaging, which reduces the size of the transmitted file, speeds up processing and reduces printing time. However, the result may look different on different printers, and in Macintosh the language is not supported.
To the main parameters of laser printersinclude the presence, type and amount of memory used in them. The latter is the main component in the printer controller. It contains an array of dots that forms an image, raw data and commands sent by a computer, as well as fonts, forms and graphics. The parameters of a laser printer are directly dependent on the amount of internal memory. The larger it is, the more data it can use at the same time.
In addition, additional memory allowsspeed up printing, as the controller can prepare a raster image of the page while the previous one is printed. This does not increase the maximum print speed, the printer will simply be more often to achieve it.
Many personal and office printerssupplied as standard - only with enough memory to print regular text documents. Since the graphics occupy a significant part of it, the device is not capable of printing large images. In addition, additional fonts can be stored in memory, which reduces the space available for images. Additional memory is often needed for complex applications such as graphics, presentations, and desktop publishing. Thus, the laser printers parameters of a photo, text files (their size, the number of used fonts, the degree of loading) that you want to print, have a significant impact.
The memory usually comes on a PCB,which is inserted into the printer controller. In some devices, it has the design features of a printer manufacturer, in others it is possible to use standard modules designed for a PC.
Since the printer controller isspecialized computer, then it needs access to the data. Small devices store information in ROM, but users who use many fonts, such as graphic designers, may need additional storage space. And some printers provide the ability to connect a hard disk or SSD. The drives can be embedded or supplied with their own power and connected to the printer with a cable.
Another question being asked whenchoose a laser printer: "What parameters depend on the paper used?" Laser printers usually use sheet stationery. The page size is limited by the size of the input tray - the container inserted into the paper feeder. Most laser printers come with trays of the same standard size, which in the USA is called Letter (8.5 x 11 inches), and the rest of the world is A4 (210 mm × 297 mm). Other paper sizes can be used with trays of the appropriate size, usually sold separately, or in a very awkward manual feed mode. Therefore, the main parameters of laser printers include the paper format used in them.
Some models allow you to customize the tray undervarious paper sizes. Desktop laser printers, due to their size, are not designed for paper sizes larger than A4 or Letter. Large printers are capable of printing on A3 or 17 "x11" paper at a speed twice lower than the nominal one.
Besides paper, most laser printersIt can also print on other materials, including thin cardboard, stickers and projection films. It is also possible to print on envelopes using a manual feed or with an optional envelope feeder.
The number and capacity of trays depends on the size andtype of printer. Most personal printers have one input feeder per 100 sheets of standard paper and a manual feed device. Office printers usually have two trays of 250 sheets each. Workgroup printers are equipped with special electric drives with a capacity of 1000 sheets. Large production printers can have several feeders with a motor drive with a capacity of up to 3,500 sheets each.
The possibility of duplex printing also applies toThe main parameters of laser printers. Most desktop devices are simplex, i.e. they print on one side of the paper. Some are equipped with an optional duplex module that turns a sheet of paper over before printing the other side. Almost all outdoor printers are equipped with an integrated duplex unit. Duplex is necessary when printing working documentation, technical manuals, but is not necessary for the needs of office printing.
Двухсторонние печатают одну сторону бумаги, turn it over and then print it on the other side, i.e., two printing operations are expended on one sheet. Because of this, the printing speed of duplex printers is half as much as one-sided.
For office users usually duplexno printer is needed, but in rare cases duplex printing is necessary. Therefore, printers allow you to work in the "manual duplex" mode when one side of the document is printed, and then the user turns the sheet of paper and continues printing. Manual duplex printing of multi-page documents is complicated, as it requires the software to print even and odd pages separately.
Duplexes are usually less reliable than simplexes.since the paper rotation mechanism is mechanically complicated, and the paper can jam in it. In addition, the printing mechanism does not always feed the paper perpendicularly, so the edge of the printed sheet is not always parallel to the edge of the paper. This bias is especially noticeable with double-sided printing.
In addition to the above, the main parameters of laser printers include:
The best multi-functional devices in 2016,According to the British computer magazine PC Advisor, the following are: Samsung Xpress M2022W, Xpress M2070W (laser printers) and Samsung MFP. Their parameters are such that they allow almost any user to choose a device to their liking. Next, we consider them in more detail.
Samsung Xpress M2875FW - Samsung Laser Printer. Options :
HP Color LaserJet Pro MFP M277dw - HP Laser Printer. What parameters to consider:
Canon i-SENSYS MF6180dw - Canon laser printer. Main settings:
