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Encyclopedia > Laser printer
1993 Apple LaserWriter Pro 630 laser printer
1993 Apple LaserWriter Pro 630 laser printer

This article is part of the series on the
History of printing Image File history File links Apple_LaserWriter_Pro_630. ... Image File history File links Apple_LaserWriter_Pro_630. ... The history of printing begins with attempts to streamline communication of commerce, law, religion and culture. ...

Technologies
Woodblock printing 200 AD
Movable type 1040
Intaglio 1430s
Printing press 1439
Lithography 1796
Offset press by 1800s
Chromolithography 1837
Rotary press 1843
Flexography 1890s
Screen-printing 1907
Dye-sublimation 1957
Photocopier 1960s
Pad printing 1960s
Laser printer 1969
Dot matrix printer 1970
Thermal printer
Inkjet printer 1976
Digital press 1993
3D printing
v  d  e

A laser printer is a common type of computer printer that rapidly produces high quality text and graphics on plain paper. As with digital photocopiers and MFPs, laser 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. Yuan Dynasty woodblock edition of a Chinese play For the use of the technique in art, see Woodcut on the technique, and Old master print for the history in Europe and woodblock printing in Japan. ... For the weblog software, see Movable Type. ... For other uses, see Intaglio. ... The printing press is a mechanical device for printing many copies of a text on rectangular sheets of paper. ... Lithography is a method for printing on a smooth surface. ... Offset printing is a widely used printing technique where the inked image is transferred (or offset) from a plate to a rubber blanket, then to the printing surface. ... Folding Card, The Old Woman Who Lived in A Shoe, 6 April 1883. ... This article does not cite its references or sources. ... Flexo redirects here. ... Screen-printing, also known as silkscreening or serigraphy, is a printmaking technique that creates a sharp-edged single-color image using a stencil and a porous fabric. ... Samsung SPP-2040 working. ... A small, much-used Xerox copier in a high school library. ... There are very few or no other articles that link to this one. ... A dot matrix printer or impact matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. ... A thermal printer (or direct thermal printer) produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. ... An Epson inkjet printer Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any medium. ... Digital printing is the reproduction of digital images on physical surface, such as common or photographic paper, film, cloth, plastic, etc. ... Three-dimensional printing is a method of converting a virtual 3D model into a physical object. ... A computer printer, or more commonly a printer, produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. ... A small, much-used Xerox copier in a high school library. ... An MFP (Multi Function Printer/Product/Peripheral), multifunctional, all-in-one (AiO), or mopier (Multiple Optical coPIER) or Multifunction Device (MFD), is an office machine that includes the following functionality in one physical body, so as to have a smaller footprint in a home or small-business setting (the SoHo... Xerography (or Electrophotography) is a photocopying technique developed by Chester Carlson (Born Feb 8 1906 - Died Sep 19 1968) in 1938 and patented on October 6, 1942. ...

Contents

Overview

Laser printers have many significant advantages over other types of printers. Unlike impact printers, laser 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 laser printers can print over 100 pages per minute (6000 pages per hour). Very high-speed laser 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. A computer printer, or more commonly a printer, produces a hard copy (permanent human-readable text and/or graphics) of documents stored in electronic form, usually on physical print media such as paper or transparencies. ... Lithography is a method for printing on a smooth surface. ...


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 laser 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 laser 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. An Epson inkjet printer Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any medium. ... A dot matrix printer or impact matrix printer normally refers to a type of computer printer with a print-head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. ...


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 laser printers to small fixed paper sizes such as letter or A4. Most laser 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.


History

The laser printer, based on a modified xerographic copier, was invented at Xerox in 1969 by researcher Gary Starkweather, who had a fully functional networked printer system working by 1971.[1][2] Laser printing eventually became a multibillion-dollar business for Xerox. Xeroxs former headquarters in Stamford (now headquartered in Norwalk) This article is about the company. ... Gary K. Starkweather is an American engineer and inventor. ... Year 1971 (MCMLXXI) was a common year starting on Friday (link will display full calendar) of the 1971 Gregorian calendar. ...


The first commercial implementation of a laser printer was the IBM model 3800 in 1976, 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. For other uses, see IBM (disambiguation) and Big Blue. ... Year 1976 (MCMLXXVI) was a leap year starting on Thursday (link will display full calendar) of the Gregorian calendar. ...


The first laser printer designed for use with an individual computer 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 laser 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 laser printers from Brother Industries, IBM, and others. The Star workstation, officially known as the 8010 Star Information System, was introduced by Xerox Corporation in 1981. ... AUGUST 25 1981 US Marine Sean Vance is Born on the 25th of August {ear nav|1981}} Year 1981 (MCMLXXXI) was a common year starting on Thursday (link displays the 1981 Gregorian calendar). ... The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is a very large, global company headquartered in Palo Alto, California, United States. ... Image:1984 HP Laserjet. ... This article is about the year. ... Canon Inc. ... Brother Industries, Ltd. ... For other uses, see IBM (disambiguation) and Big Blue. ...


Most noteworthy was the role the laser printer played in popularizing desktop publishing with the introduction of the Apple LaserWriter for the Apple Macintosh, along with Aldus PageMaker software, in 1985. With these products, users could create documents that would previously have required professional typesetting. Adobe InDesign CS2, one of many popular desktop publishing applications. ... Apple Inc. ... The Apple LaserWriter was one of the first laser printers available to the mass market. ... For other uses, see Macintosh (disambiguation) and Mac. ... PageMaker was the first desktop publishing program, introduced in 1985 by Aldus Corporation, initially for the Apple Macintosh but soon after also for the PC. It relies on Adobe Systems PostScript page description language. ... This article is about the year. ... This article or section is in need of attention from an expert on the subject. ...


As with most electronic devices, the cost of laser printers has fallen markedly over the years. In 1985 the HP LaserJet sold for $2995.00 and weighed 71 pounds (32 kg). The Apple LaserWriter (which shipped with a more powerful processor and the Postscript page description language) weighed about 70 lb and cost almost $7000.00. (Work rules in the factory producing the Laserwriter forbade any worker lifting the printer unassisted.) Today a comparable laser printer with more memory, a higher speed and duplexing capability costs about $300.00. A bare-bones laser printer costs less than $100.00.


How it works

Main article: Xerography

There are typically seven steps involved in the laser printing process: Chester F. Carlson Xerography (or Electrophotography) is a photocopying technique developed by Chester Carlson in 1938 and patented on October 6, 1942. ...


Raster image processing

Generating the raster image data
Generating the raster image data

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 a Raster Image Processor (RIP), typically built into the laser printer. The source material may be encoded in any number of special page description languages such as Adobe PostScript (PS) or HP Printer Command Language (PCL), 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. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Raster can refer to either of the following items: Raster graphics, Bit array, the general-purpose data structure, or The scanning pattern of the electron beam to a screen of a Cathode Ray Tube. ... A scan line is one line, or row, in a raster scanning pattern, such as a video line on a Cathode ray tube (CRT) display of a television or computer. ... A raster image processor (RIP) is a component used in a printing system which produces a bitmap. ... Printer Command Language, more commonly referred to as PCL, is a Page description language (PDL) developed by HP as a printer protocol and has become a de facto industry standard. ...

Charging

Appyling a negative charge to the photosensitive drum
Appyling a negative charge to the photosensitive drum

A corona wire (in older printers) or a primary charge roller projects an electrostatic 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. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking (also known as arcing) is not favoured. ... Electrostatics is the branch of physics that deals with the force exerted by a static (i. ...


Numerous patents describe the photosensitive drum coating as a silicon sandwich with a photocharging layer, a charge leakage barrier layer, as well as a surface layer. One version uses amorphous silicon containing hydrogen as the light receiving layer, Boron nitride as a charge leakage barrier layer, as well as a surface layer of doped silicon, notably silicon with oxygen or nitrogen which at sufficient concentration resembles machining silicon nitride; the effect is that of a light chargeable diode with minimal leakage, that resists scuffing A patent is a set of exclusive rights granted by a government to an inventor or applicant for a limited amount of time (normally maximum 20 years from the filing date, depending on extension). ... Not to be confused with Silicone. ... Boron nitride is a binary chemical compound, consisting of equal proportions of boron and nitrogen, with formula BN. Structurally, it is isoelectronic to carbon and takes on similar physical forms: a hexagonal, graphite-like one, and a cubic, diamond-like one. ... Silicon nitride (Si3N4) is hard, solid substance, that can be obtained by direct reaction between silicon and nitrogen in high temperatures. ... Closeup of the image below, showing the square shaped semiconductor crystal various semiconductor diodes, below a bridge rectifier Structure of a vacuum tube diode In electronics, a diode is a two-terminal component, almost always one that has electrical properties which vary depending on the direction of flow of charge...

Exposing

How the bitmap is written to the photosensitive drum.
How the bitmap is written to the photosensitive drum.

The laser is aimed at a rotating polygonal mirror, which directs the laser beam through a system of lenses and mirrors onto the photoreceptor. The beam sweeps across the photoreceptor at an angle to make the sweep straight across the page; the cylinder continues to rotate during the sweep and the angle of sweep compensates for this motion. The stream of rasterized data held in memory turns the laser on and off to form the dots on the cylinder. (Some printers switch an array of light emitting diodes spanning the width of the page, but these devices are not "Laser Printers".) Lasers are used because they generate a narrow beam over great distances. The laser beam neutralizes (or reverses) the charge on the white parts of the image, leaving a static electric negative image on the photoreceptor surface to lift the toner particles. Image File history File links Laser_printer-Writing. ... Image File history File links Laser_printer-Writing. ... Various light-emitting diodes (5 mm reds, 3 mm greens and yellows) A light-emitting diode (LED) is a semiconductor device that emits incoherent monochromatic light when electrically biased in the forward direction. ... Static electricity is a class of phenomena involving the net charge present on an object; typically referring to charged object with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... A color toner bottle Toner is a powder used in laser printers and photocopiers to form the text and images on the printed paper. ...

Developing

The surface with the latent image is exposed to toner, fine particles of dry plastic powder mixed with carbon black or coloring agents. The charged toner particles are given a negative charge, and are electrostatically attracted to the photoreceptor where the laser wrote the latent image. Because like charges repel, the negatively charged toner will not touch the drum where light has not removed the negative charge. A color toner bottle Toner is a powder used in laser printers and photocopiers to form the text and images on the printed paper. ...


The overall darkness of the printed image is controlled by the high voltage charge applied to the supply toner. Once the charged toner has jumped the gap to the surface of the drum, the negative charge on the toner itself repels the supply toner and prevents more toner from jumping to the drum. If the voltage is low, only a thin coat of toner is needed to stop more toner from transferring. If the voltage is high, then a thin coating on the drum is too weak to stop more toner from transferring to the drum. More supply toner will continue to jump to the drum until the charges on the drum are again high enough to repel the supply toner. At the darkest settings the supply toner voltage is high enough that it will also start coating the drum where the initial unwritten drum charge is still present, and will give the entire page a dark shadow.


Transferring

The photoreceptor is pressed or rolled over paper, transferring the image. Higher-end machines use a positively charged transfer roller on the back side of the paper to pull the toner from the photoreceptor to the paper.


Fusing

Melting toner into the paper using heat and pressure.
Melting toner into the paper using heat and pressure.

The paper passes through rollers in the fuser assembly where heat and pressure (up to 200 Celsius) bond the plastic powder to the paper. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ...


One roller is usually a hollow tube (heat roller) and the other is a rubber backing roller (pressure roller). A radiant heat lamp is suspended in the center of the hollow tube, and its infrared energy uniformly heats the roller from the inside. For proper bonding of the toner, the fuser roller must be uniformly hot.


The fuser accounts for up to 90% of a printer's power usage. The heat from the fuser assembly can damage other parts of the printer, so it is often ventilated by fans to move the heat away from the interior. The primary power saving feature of most copiers and laser printers is to turn off the fuser and let it cool. Resuming normal operation requires waiting for the fuser to return to operating temperature before printing can begin.


Some printers use a very thin flexible metal fuser roller, so there is less mass to be heated and the fuser can more quickly reach operating temperature. This both speeds printing from an idle state and permits the fuser to turn off more frequently to conserve power.


If paper moves through the fuser more slowly, there is more roller contact time for the toner to melt, and the fuser can operate at a lower temperature. Smaller, inexpensive laser printers typically print slowly, due to this energy-saving design, compared to large high speed printers where paper moves more rapidly through a high-temperature fuser with a very short contact time.

Cleaning

When the print is complete, an electrically neutral soft plastic blade cleans any excess toner from the photoreceptor and deposits it into a waste reservoir, and a discharge lamp removes the remaining charge from the photoreceptor.


Toner may occasionally be left on the photoreceptor when unexpected events such as a paper jam occur. The toner is on the photoconductor ready to apply, but the operation failed before it could be applied. The toner must be wiped off and the process restarted.


Waste toner cannot be reused for printing because it can be contaminated with dust and paper fibers. A quality printed image requires pure, clean toner. Reusing contaminated toner can result in splotchy printed areas or poor fusing of the toner into the paper. There are some exceptions however, most notably some Brother and Toshiba laser printers, which use a patented method to clean and recycle the waste toner.[3][4] Brother Industries, Ltd. ... Toshiba Corporations headquarters (Center) in Hamamatsucho, Tokyo Toshiba Corporation sales by division for year ending March 31, 2005 Toshiba Corporation ) (TYO: 6502 ) is a Japanese multinational conglomerate manufacturing company, headquartered in Tokyo, Japan. ...


Multiple steps occurring at once

Once the raster image generation is complete all steps of the printing process can occur one after the other in rapid succession. This permits the use of a very small and compact unit, where the photoreceptor is charged, rotates a few degrees and is scanned, rotates a few more degrees and is developed, and so forth. The entire process can be completed before the drum completes one revolution.


Different printers implement these steps in distinct ways. Some "laser" printers actually use a linear array of light-emitting diodes to "write" the light on the drum (see LED printer). The toner is based on either wax or plastic, so that when the paper passes through the fuser assembly, the particles of toner melt. The paper may or may not be oppositely charged. The fuser can be an infrared oven, a heated pressure roller, or (on some very fast, expensive printers) a xenon flash lamp. The Warm Up process that a laser printer goes through when power is initially applied to the printer consists mainly of heating the fuser element. Many printers have a toner-conservation mode or "economode", which can be substantially more economical with fuser consumption at the price of slightly lower contrast. For other uses, see Laser (disambiguation). ... LED redirects here. ... LED printers are identical in principle to laser printers except for the light source used. ... For other uses, see Wax (disambiguation). ... For other uses, see Plastic (disambiguation). ... Xenon flash lamp being fired. ...


Color laser printers

Color laser printers use colored toner (typically, but not always cyan, magenta, yellow, and black-- see CMYK) in four steps or passes. Color adds complexity to the printing process because very slight misalignments known as registration errors can occur between printing each color, causing unintended color fringing, blurring, or light/dark streaking along the edges of colored regions. Cyan (from Greek κυανοs, meaning blue) may be used as the name of any of a number of a range of colors in the blue/green part of the spectrum. ... Magenta is a color made up of equal parts of red and blue light. ... This article is about the color. ... This article is about the color. ... Cyan, magenta, yellow, and key (black) CMYK (or sometimes YMCK) is a subtractive color model used in color printing. ...


To permit a high registration accuracy, some color laser printers use a large belt the size of a full sheet of paper to generate the image. All four layers of toner are precisely applied to the belt, and the combined layers are then applied to the paper in a single step.


Color laser printers typically require four times as much memory as a monochrone printer to print the same size document, because each of the four CMYK color separations needs to be rasterized and stored in memory before printing can begin.


DPI Resolution

1200 DPI printers were commonly available during 2008, with 2400 DPI electrophotographic printing plate makers, essentially laser printers that print on plastic sheets, available


Laser printer maintenance

Most consumer and small business laser printers use a cartridge that combines the photoreceptor (sometimes called "photoconductor unit") with the supply toner and waste toner bottles and various wiper blades. When the supply toner is consumed, replacing the cartridge automatically replaces the photoreceptor, waste toner bottle, and blades.


Some small consumer printers use a separate toner bottle that can be replaced several times separately from the photoreceptor, allowing for a much lower cost of operation. High-volume business laser printers separate all components into individual modules.


After printing about fifty thousand pages, typical maintenance is to vacuum the mechanism, and clean or replace the paper handling rollers. The rollers have a thick rubber coating, which eventually suffers wear and becomes covered with slippery paper dust. They can usually be cleaned with a damp lint-free rag and there are chemical solutions that can help restore the traction of the rubber.


After one hundred thousand pages, it is common for the fuser assembly to either wear out or need cleaning. The fuser heating rollers are often coated with an oil that prevents toner from sticking to the rollers. A small amount of the oil coating is absorbed by each piece of paper passing through the fuser, eventually requiring the oil supply to be replenished or the pressure roller assembly to be completely replaced. It is common for the fuser assembly to be left unmaintained until the toner starts sticking to the rollers, which creates a repeating ragged line on every printed page due to the rollers not being smooth anymore.


Color laser printers are typically more expensive and higher maintenance than monochrome laser printers since they contain more imaging components. Color laser printers intended for high volume use may require supplies that monochrome printers do not use, while the least expensive consumer color laser printers are expected to wear out and fail four times faster during color printing, compared to monochrome printing.[citation needed]


Due to current market incentives, the least expensive consumer color laser printers often cost less than the total value of the replacement parts inside the printer. The photoreceptor assembly for example may last 100,000 pages but may cost as much to replace as buying a new printer with new toner cartridges included.


Steganographic anti-counterfeiting ("secret") marks

An illustration of small yellow dots on white paper, generated by a color laser printer.
An illustration of small yellow dots on white paper, generated by a color laser printer.
Main article: Printer steganography

Many modern color laser printers mark printouts by a nearly invisible dot raster, for the purpose of identification. The dots are yellow and about 0.1 mm in size, with a raster of about 1 mm. This is purportedly the result of a deal between the US government and printer manufacturers to help track counterfeiters.[5] Printer steganography is a type of steganography produced by color printers, including HP and Xerox brand printers, where tiny yellow dots are added to each page. ... Suppose the smiley face in the top left corner is an RGB bitmap image. ... ... A counterfeit is an imitation that is made with the intent to deceptively represent its content or origins. ...


The dots encode data such as printing date, time, and printer serial number in binary-coded decimal on every sheet of paper printed, which allows pieces of paper to be traced by the manufacturer to identify the place of purchase, and sometimes the buyer. Digital rights advocacy groups such as the Electronic Frontier Foundation are concerned that this is a threat to the privacy and anonymity of those who print.[6] In computing and electronic systems, binary-coded decimal (BCD) is an encoding for decimal numbers in which each digit is represented by its own binary sequence. ... EFF Logo The Electronic Frontier Foundation (EFF) is an international non-profit advocacy and legal organization based in the United States with the stated purpose of being dedicated to preserving free speech rights such as those protected by the First Amendment to the United States Constitution in the context of...

Safety hazards, health risks, and precautions

Shock hazards

Although modern printers include many safety interlocks and protection circuits, it is possible for a high voltage or a residual voltage to be present on the various rollers, wires, and metal contacts inside a laser printer. Care should be taken to avoid unnecessary contact with these parts to reduce the potential for painful electrical shock. An interlock is a device used to help prevent a machine from harming its operator or damaging itself by stopping the machine when tripped. ...


Toner clean-up

Toner particles are designed to have electrostatic properties and can develop static-electric charges when they rub against other particles, objects, or the interiors of transport systems and vacuum hoses. Because of this and its small particle size, toner should not be vacuumed with a conventional home vacuum cleaner. Static discharge from charged toner particles can ignite dust in the vacuum cleaner bag or create a small explosion if sufficient toner is airborne. This may damage the vacuum cleaner or start a fire. In addition, toner particles are so fine that they are poorly filtered by conventional household vacuum cleaner filter bags and blow through the motor or back into the room.


Toner particles melt (or fuse) when warmed. Small toner spills can be wiped up with a cold, damp cloth.


If toner spills into the laser printer, a special type of vacuum cleaner with an electrically conductive hose and a high efficiency (HEPA) filter may be needed for effective cleaning. These are called ESD-safe (Electrostatic Discharge-safe) or toner vacuums. Similar HEPA-filter equipped vacuums should be used for clean-up of larger toner spills. HEPA (IPA: ) is a type of air filter. ...


Toner is easily cleaned from most water-washable clothing. As toner is a wax or plastic powder with a low melting temperature, it must be kept cold during the cleaning process. Washing a toner stained garment in cold water is often successful. Even warm water is likely to result in permanent staining. The washing machine should be filled with cold water before adding the garment. Washing through two cycles improves the chances of success. The first may use hand wash dish detergent, with the second cycle using regular laundry detergent. Residual toner floating in the rinse water of the first cycle will remain in the garment and may cause a permanent graying. A clothes dryer or iron should not be used until it is certain that all the toner has been removed.


Ozone hazards

As a natural part of the printing process, the high voltages inside the printer can produce a corona discharge that generates a small amount of ionized oxygen and nitrogen, forming ozone and nitrogen oxides. In larger commercial printers and copiers, a carbon filter in the air exhaust stream breaks down these oxides to prevent pollution of the office environment. In electricity, a corona discharge is an electrical discharge brought on by the ionization of a fluid surrounding a conductor, which occurs when the potential gradient exceeds a certain value, in situations where sparking (also known as arcing) is not favoured. ... For other uses, see Ozone (disambiguation). ... Nitrogen has six different oxides: Nitric oxide (NO) Nitrous oxide (N2O) Nitrogen dioxide (NO2) Dinitrogen trioxide (N2O3) Dinitrogen tetroxide (N2O4) Dinitrogen pentoxide (N2O5) The term nitrogen oxide is imprecise and can be used to refer to any of these or to a mixture of them. ...


However, some ozone escapes the filtering process in commercial printers, and ozone filters are not used in many smaller consumer printers. When a laser printer or copier is operated for a long period of time in a small, poorly ventilated space, these gases can build up to levels at which the odor of ozone or irritation may be noticed. A potential for creating a health hazard is theoretically possible in extreme cases.[citation needed]


Respiratory health risks

According to a recent study conducted in Queensland, Australia, some printers emit sub-micrometre particles which some suspect may be associated with respiratory diseases.[7] Of 63 printers evaluated in the Queensland University of Technology study, 17 of the strongest emitters were made by Hewlett-Packard and one by Toshiba. The machine population studied, however, was only those machines already in place in the building and was thus biased toward specific manufacturers. The authors noted that particle emissions varied substantially even among the same model of machine. According to Professor Morawska of Queensland University, one printer emitted as many particles as a burning cigarette.[8] A micrometre (American spelling: micrometer, symbol µm) is an SI unit of length equal to one millionth of a metre, or about a tenth of the diameter of a droplet of mist or fog. ... The Hewlett-Packard Company (NYSE: HPQ), commonly known as HP, is a very large, global company headquartered in Palo Alto, California, United States. ... Toshiba Corporations headquarters (Center) in Hamamatsucho, Tokyo Toshiba Corporation sales by division for year ending March 31, 2005 Toshiba Corporation ) (TYO: 6502 ) is a Japanese multinational conglomerate manufacturing company, headquartered in Tokyo, Japan. ...

"The health effects from inhaling ultrafine particles depend on particle composition, but the results can range from respiratory irritation to more severe illness such as cardiovascular problems or cancer." (Queensland UT).[9]

A 2006 study in Japan found that laser printers increase concentrations of styrene, xylenes, and ozone, and that ink-jet printers emitted pentanol.[10] For transport in plants, see Vascular tissue. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... QUT Gardens Point Campus Queensland University of Technology (QUT) is located in Brisbane, Queensland, and is one of Australias largest universities, however is globally known as one of the worst in the region. ... C8H8 redirects here. ... The term xylenes refers to a group of 3 benzene derivatives which encompasses ortho-, meta-, and para- isomers of dimethyl benzene. ... For other uses, see Ozone (disambiguation). ... An Epson inkjet printer Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any medium. ... Pentanol, more properly called 1-pentanol, is a higher alcohol with a five carbon atoms and a general formula of C5H11OH. H H H H H | | | | | H - C - C - C - C - C - OH | | | | | H H H H H Also see amyl alcohol. ...


Muhle et al. (1991) reported that the responses to chronically inhaled copying toner, a plastic dust pigmented with carbon black, titanium dioxide and silica were also similar qualitatively to titanium dioxide and diesel exhaust.[11]


See also

A daisy wheel printer is a type of computer printer that produces high-quality type, and is often referred to as a letter-quality printer (this in contrast to high-quality dot-matrix printers, capable of near-letter-quality, or NLQ, output). ... A dot matrix printer or impact matrix printer refers to a type of computer printer with a print head that runs back and forth on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like a typewriter. ... An Epson inkjet printer Inkjet printers operate by propelling variably-sized droplets of liquid or molten material (ink) onto almost any medium. ... LED printers are identical in principle to laser printers except for the light source used. ... A thermal printer (or direct thermal printer) produces a printed image by selectively heating coated thermochromic paper, or thermal paper as it is commonly known, when the paper passes over the thermal print head. ... Samsung SPP-2040 working. ... This article is about hidden messages. ...

External links

  • Howstuffworks "How Laser Printers Work"
  • Is Your Printer Spying On You? (by EFF)
  • Detailed description, modelling and simulation of the electrophotographic print process (technical; 7.2MB)
  • Xerographic Color Technology (pdf), Katun (supplier of OEM-compatible imaging supplies, photoreceptors, and parts), July 1999

EFF Logo The Electronic Frontier Foundation (EFF) is an international non-profit advocacy and legal organization based in the United States with the stated purpose of being dedicated to preserving free speech rights such as those protected by the First Amendment to the United States Constitution in the context of...

References

  1. ^ Edwin D. Reilly (2003). Milestones in Computer Science and Information Technology. Greenwood Press. ISBN 1573565210. 
  2. ^ Roy A. Allan (2001). A History of the Personal Computer: The People and the Technology. Allan Publishing. ISBN 0968910807. 
  3. ^ U.S. Patent 5231458 - Printer which utilizes previously used developer
  4. ^ Simplified explanation of Brother waste toner recycling process at fixyourownprinter.com
  5. ^ Electronic Frontier Foundation- privacy on printers
  6. ^ Electonic Frontier Foundation Threat to privacy
  7. ^ Particle Emission Characteristics of Office Printers.
  8. ^ Particle Emission Characteristics of Office Printers.
  9. ^ Study reveals the dangers of printer pollution.
  10. ^ Are Laser Printers Hazardous to Your Health? - Yahoo! News.
  11. ^ 11.6 METALS. 070821 epa.gov

  Results from FactBites:
 
Laser Printer Shopping and Price comparison (1100 words)
Printer - B / Laser Printer /W - laser - Legal, A4 - 2400 dpi x 600 dpi - up to 16 ppm - capacity: 250 sheets - USB - The Brother HL-2030 is stylishly designed and compact enough to fit onto a shelf or workstation.
Printer - B/W - laser - Legal, A4 - 1200 dpi x 600 dpi - up to 20 ppm - capacity: 150 sheets - USB - Samsung has created a substantial line-up of inkjet and laser printers, a line up that is being expanded with mid-range printers as customers demand greater speed and a hi...
Laser Printer 1 2 3 4 5 6 7 8...
Laser printer - Wikipedia, the free encyclopedia (1415 words)
Like photocopiers, laser 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.
The first laser printer designed for use with an individual computer was released with the Xerox Star 8010 in 1981; however, although it was highly innovative, the Star was an expensive ($17,000) system that was only purchased by a small number of laboratories and institutions.
Lasers (now typically laser diodes) are used because they generate a coherent beam of light for a high degree of accuracy.
  More results at FactBites »

 
 

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