A printer Call customer service phone number is to contact printers care tech support help center helpline desk technical HelpDeskusacanadalive chat 1800 1 800 tollfree toll☎free telephone Email person 24×7 hour.Printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and multifunction printers (MFPs), printers employ a xerographic printing process but differ from analog photocopiers in that the image is produced by the direct scanning of a laser beam across the printer’s photoreceptor.
Wireless Laserjet Inkjet Multifunction
A laser beam projects an image of the page to be printed onto an electrically charged rotating drum coated with selenium or, more common in modern printers, organic photoconductors. Photoconductivity removes charge from the areas exposed to light. Dry ink (toner) particles are then electro statically picked up by the drum’s charged areas. The drum then prints the image onto paper by direct contact and heat, which fuses the ink to the paper.
Unlike impact printers, printer speed can vary widely, and depends on many factors, including the graphic intensity of the job being processed. The fastest models can print over 200 monochrome pages per minute (12,000 pages per hour). The fastest color printers can print over 100 pages per minute (6000 pages per hour). Very high-speed printers are used for mass mailings of personalized documents, such as credit card or utility bills, and are competing with lithography in some commercial applications.
The cost of this technology depends on a combination of factors, including the cost of paper, toner, and infrequent drum replacement, as well as the replacement of other consumables such as the fuser assembly and transfer assembly. Often printers with soft plastic drums can have a very high cost of ownership that does not become apparent until the drum requires replacement.
A duplexing printer (one that prints on both sides of the paper) can halve paper costs and reduce filing volumes. Formerly only available on high-end printers, duplexers are now common on mid-range office printers, though not all printers can accommodate a duplexing unit. Duplexing can also give a slower page-printing speed, because of the longer paper path.
In comparison with the printer, most inkjet printers and dot-matrix printers simply take an incoming stream of data and directly imprint it in a slow lurching process that may include pauses as the printer waits for more data. A printer is unable to work this way because such a large amount of data needs to output to the printing device in a rapid, continuous process. The printer cannot stop the mechanism precisely enough to wait until more data arrives, without creating a visible gap or misalignment of the dots on the printed page.
Instead the image data is built up and stored in a large bank of memory capable of representing every dot on the page. The requirement to store all dots in memory before printing has traditionally limited printers to small fixed paper sizes such as letter or A4. Most printers are unable to print continuous banners spanning a sheet of paper two meters long, because there is not enough memory available in the printer to store such a large image before printing begins.
The printer was invented at Xerox in 1969 by researcher Gary Starkweather, who had an improved printer working by 1971 and incorporated into a fully functional networked printer system by about a year later. The prototype was built by modifying an existing xerographic. Starkweather disabled the imaging system and created a spinning drum with 8 mirrored sides, with a laser focused on the drum. Light from the laser would bounce off the spinning drum, sweeping across the page as it traveled through the copier. The hardware was completed in just a week or two, but the computer interface and software took almost 3 months to complete.
The first commercial implementation of a printer was the IBM model 3800 in 1975, used for high-volume printing of documents such as invoices and mailing labels. It is often cited as “taking up a whole room,” implying that it was a primitive version of the later familiar device used with a personal computer. While large, it was designed for an entirely different purpose. Many 3800s are still in use.
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The first printer designed for use in an office setting was released with the Xerox Star 8010 in 1981. Although it was innovative, the Star was an expensive ($17,000) system that was purchased by only a relatively small number of businesses and institutions. After personal computers became more widespread, the first printer intended for a mass market was the HP LaserJet 8ppm, released in 1984, using a Canon engine controlled by HP software. The HP LaserJet printer was quickly followed by printers from Brother Industries, IBM, and others. First-generation machines had large photosensitive drums, of circumference greater than the paper length. Once faster-recovery coatings were developed, the drums could touch the paper multiple times in a pass, and could therefore be smaller in diameter.
As with most electronic devices, the cost of printers has fallen markedly over the years. In 1984, the HP LaserJet sold for $3500, had trouble with even small, low resolution graphics, and weighed 71 pounds (32 kg). Low end monochrome printers often sell for less than $75 as of 2008. These printers tend to lack onboard processing and rely on the host computer to generate a raster image (see Winprinter), but still will outperform the LaserJet Classic in nearly all situations.
How it works
Raster image processing
Each horizontal strip of dots across the page is known as a raster line or scan line. Creating the image to be printed is done by aRaster Image Processor (RIP), typically built into the printer. The source material may be encoded in any number of special page description languages such as Adobe PostScript (PS), HP Printer Command Language (PCL), or Microsoft XML Page Specification (XPS), as well as unformatted text-only data. The RIP uses the page description language to generate a bitmap of the final page in the raster memory. Once the entire page has been rendered in raster memory, the printer is ready to begin the process of sending the rasterized stream of dots to the paper in a continuous stream.
The first Hewlett Packard LaserJet only had 128 kilobytes of memory. It typically was used to print text only, and did not operate like modern graphical printers. The page character information was stored in only a few kilobytes, and during printing the actual dot patterns for each raster scan line was looked up in font bitmap tables stored in Read Only Memory (ROM). Additional fonts were stored on ROM cartridges, plugged into expansion slots.
For fully graphical output using a page description language, a minimum of 1 megabyte of memory is needed to store an entire monochrome letter/A4 sized page of dots at 300 dpi. At 300 dpi, there are 90,000 dots per square inch (300 dots per linear inch). A typical 8.5 x 11 sheet of paper has 0.25 inch margins, reducing the printable area to 8.0 x 10.5 inches, or 84 square inches. 84 sq/in x 90,000 dots per sq/in = 7,560,000 dots. Meanwhile 1 megabyte = 1,048,576 bytes, or 8,388,608 bits, which is just large enough to hold the entire page at 300 dpi, leaving about 100 kilobytes to spare for use by the raster image processor.
In a colour printer, each of the four CYMK toner layers is stored as a separate bitmap, and all four layers are typically preprocessed before printing begins, so a minimum of 4 megabytes is needed for a full-colour letter-size page at 300 dpi.
Memory requirements increase with the square of the dpi, so 600 dpi requires a minimum of 4 megabytes for monochrome, and 16 megabytes for colour at 600 dpi. Some printers are capable of variable size dots and interstitial dots; these additional functions may require many times more memory over the minimums described here.
Printers capable of tabloid and larger size may include memory expansion slots. If insufficient memory is available, some features may be disabled, such as being able to print in colour at letter size but only capable of monochrome at tabloid size. Purchasing additional memory may permit printing in colour at the larger size.
In older printers, a corona wire positioned parallel to the drum, or in more recent printers, a primary charge roller, projectsanelectrostatic charge onto the photoreceptor (otherwise named the photoconductor unit), a revolving photosensitive drum or belt, which is capable of holding an electrostatic charge on its surface while it is in the dark.
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