Textile
A textile is a flexible material consisting of a network of natural or artificial fibers. Yarn is produced by spinning raw fibres of wool, cotton, hemp, or other materials to produce long strands. Textiles are formed by weaving, crocheting, knotting or tatting, felting, or braiding; the related words "fabric" and "cloth" and "material" are used in textile assembly trades as synonyms for textile. However, there are subtle differences in these terms in specialized usage. A textile is any material made of interlacing fibres, including carpeting and geotextiles. A fabric is a material made through weaving, spreading, crocheting, or bonding that may be used in production of further goods. Cloth may be used synonymously with fabric but is a piece of fabric, processed; the word'textile' is from Latin, from the adjective textilis, meaning'woven', from textus, the past participle of the verb texere,'to weave'. The word'fabric' derives from Latin, most from the Middle French fabrique, or'building, thing made', earlier as the Latin fabrica'workshop.
The word'cloth' derives from the Old English clað, meaning a cloth, woven or felted material to wrap around one, from Proto-Germanic kalithaz. The first clothes, worn at least 70,000 years ago and much earlier, were made of animal skins and helped protect early humans from the ice ages. At some point people learned to weave plant fibers into textiles; the discovery of dyed flax fibres in a cave in the Republic of Georgia dated to 34,000 BCE suggests textile-like materials were made in prehistoric times. The production of textiles is a craft whose speed and scale of production has been altered beyond recognition by industrialization and the introduction of modern manufacturing techniques. However, for the main types of textiles, plain weave, twill, or satin weave, there is little difference between the ancient and modern methods. Textiles have an assortment of uses, the most common of which are for clothing and for containers such as bags and baskets. In the household they are used in carpeting, upholstered furnishings, window shades, coverings for tables and other flat surfaces, in art.
In the workplace they are used in scientific processes such as filtering. Miscellaneous uses include flags, tents, handkerchiefs, cleaning rags, transportation devices such as balloons, kites and parachutes. Textiles are used in many traditional crafts such as sewing and embroidery. Textiles for industrial purposes, chosen for characteristics other than their appearance, are referred to as technical textiles. Technical textiles include textile structures for automotive applications, medical textiles, agrotextiles, protective clothing. In all these applications stringent performance requirements must be met. Woven of threads coated with zinc oxide nanowires, laboratory fabric has been shown capable of "self-powering nanosystems" using vibrations created by everyday actions like wind or body movements. Textiles are made from many materials, with four main sources: animal, plant and synthetic; the first three are natural. In the 20th century, they were supplemented by artificial fibres made from petroleum.
Textiles are made in various strengths and degrees of durability, from the finest microfibre made of strands thinner than one denier to the sturdiest canvas. Textile manufacturing terminology has a wealth of descriptive terms, from light gauze-like gossamer to heavy grosgrain cloth and beyond. Animal textiles are made from hair, skin or silk. Wool refers to the hair of the domestic sheep or goat, distinguished from other types of animal hair in that the individual strands are coated with scales and crimped, the wool as a whole is coated with a wax mixture known as lanolin, waterproof and dirtproof. Woollen refers to a bulkier yarn produced from carded, non-parallel fibre, while worsted refers to a finer yarn spun from longer fibres which have been combed to be parallel. Wool is used for warm clothing. Cashmere, the hair of the Indian cashmere goat, mohair, the hair of the North African angora goat, are types of wool known for their softness. Other animal textiles which are made from hair or fur are alpaca wool, vicuña wool, llama wool, camel hair used in the production of coats, ponchos and other warm coverings.
Angora refers to the long, soft hair of the angora rabbit. Qiviut is the fine inner wool of the muskox. Wadmal is a coarse cloth made of wool, produced in Scandinavia 1000~1500 CE. Sea silk is an fine and valuable fabric, made from the silky filaments or byssus secreted by a gland in the foot of pen shells. Silk is an animal textile made from the fibres of the cocoon of the Chinese silkworm, spun into a smooth fabric prized for its softness. There are two main ty
Sleep
Sleep is a recurring state of mind and body, characterized by altered consciousness inhibited sensory activity, inhibition of nearly all voluntary muscles, reduced interactions with surroundings. It is distinguished from wakefulness by a decreased ability to react to stimuli, but more reactive than coma or disorders of consciousness, sleep displaying different and active brain patterns. Sleep occurs in repeating periods, in which the body alternates between two distinct modes: REM sleep and non-REM sleep. Although REM stands for "rapid eye movement", this mode of sleep has many other aspects, including virtual paralysis of the body. A well-known feature of sleep is the dream, an experience recounted in narrative form, which resembles waking life while in progress, but which can be distinguished as fantasy. During sleep, most of the body's systems are in an anabolic state, helping to restore the immune, nervous and muscular systems; the internal circadian clock promotes sleep daily at night. The diverse purposes and mechanisms of sleep are the subject of substantial ongoing research.
Sleep is a conserved behavior across animal evolution. Humans may suffer from various sleep disorders, including dyssomnias such as insomnia, hypersomnia and sleep apnea; the advent of artificial light has altered sleep timing in industrialized countries. The most pronounced physiological changes in sleep occur in the brain; the brain uses less energy during sleep than it does when awake during non-REM sleep. In areas with reduced activity, the brain restores its supply of adenosine triphosphate, the molecule used for short-term storage and transport of energy. In quiet waking, the brain is responsible for 20% of the body's energy use, thus this reduction has a noticeable effect on overall energy consumption. Sleep increases the sensory threshold. In other words, sleeping persons perceive fewer stimuli, but can still respond to loud noises and other salient sensory events. During slow-wave sleep, humans secrete bursts of growth hormone. All sleep during the day, is associated with secretion of prolactin.
Key physiological methods for monitoring and measuring changes during sleep include electroencephalography of brain waves, electrooculography of eye movements, electromyography of skeletal muscle activity. Simultaneous collection of these measurements is called polysomnography, can be performed in a specialized sleep laboratory. Sleep researchers use simplified electrocardiography for cardiac activity and actigraphy for motor movements. Sleep is divided into two broad types: non-rapid eye movement sleep and rapid eye movement sleep. Non-REM and REM sleep are so different that physiologists identify them as distinct behavioral states. Non-REM sleep after a transitional period is called slow-wave sleep or deep sleep. During this phase, body temperature and heart rate fall, the brain uses less energy. REM sleep known as paradoxical sleep, represents a smaller portion of total sleep time, it is the main occasion for dreams, is associated with desynchronized and fast brain waves, eye movements, loss of muscle tone, suspension of homeostasis.
The sleep cycle of alternate NREM and REM sleep takes an average of 90 minutes, occurring 4–6 times in a good night's sleep. The American Academy of Sleep Medicine divides NREM into three stages: N1, N2, N3, the last of, called delta sleep or slow-wave sleep; the whole period proceeds in the order: N1 → N2 → N3 → N2 → REM. REM sleep occurs as a person returns to stage 1 from a deep sleep. There is a greater amount of deep sleep earlier in the night, while the proportion of REM sleep increases in the two cycles just before natural awakening. Awakening can mean the end of sleep, or a moment to survey the environment and readjust body position before falling back asleep. Sleepers awaken soon after the end of a REM phase or sometimes in the middle of REM. Internal circadian indicators, along with successful reduction of homeostatic sleep need bring about awakening and the end of the sleep cycle. Awakening involves heightened electrical activation in the brain, beginning with the thalamus and spreading throughout the cortex.
During a night's sleep, a small amount of time is spent in a waking state. As measured by electroencephalography, young females are awake for 0–1% of the larger sleeping period. In adults, wakefulness increases in cycles. One study found 3% awake time in the first ninety-minute sleep cycle, 8% in the second, 10% in the third, 12% in the fourth, 13–14% in the fifth. Most of this awake time occurred shortly. Today, many humans wake up with an alarm clock. Many sleep quite differently on workdays versus days off, a pattern which can lead to chronic circadian desynchronization. Many people look at television and other screens before going to bed, a factor which may exacerbate disruption of the circadian cycle. Scientific studies on sleep have shown that sleep stage at awakening is an important factor in amplifying sleep inertia. Sleep timing is controlled by the circadian clock, sleep-wake homeostasis, to some extent by individual will. Sleep timing depends on hormo
Grommet
A grommet is a ring or edge strip inserted into a hole through thin material a sheet of textile fabric, sheet metal or composite of carbon fiber, wood or honeycomb. Grommets are flared or collared on each side to keep them in place, are made of metal, plastic, or rubber, they may be used to prevent tearing or abrasion of the pierced material or protection from abrasion of the insulation on the wire, line being routed through the penetration, to cover sharp edges of the piercing, or all of the above. A small grommet may be called an eyelet, used for example on shoes and sails for lacing purposes. In electrical applications these are referred to as "insulating bushings". Most common are molded rubber that are inserted into small hole diameters up to 2" in diameter. There are many hole configurations from standard round to assorted U-shapes. Larger penetrations that are irregular in shape as well as long straight edges use extruded or stamped strips of continuous length; these continuous length materials are referred to as "grommet edging".
These are quite common in applications that range from telecom switches and data center cabinets to complex and dense wire/cable and hydraulic tubing in aircraft, transportation vehicles and medical equipment. Grommets are used to reinforce holes in leather, shoes and other fabrics, they can be made of metal, rubber, or plastic, are used in common projects, requiring only the grommet itself and a means of setting it with a punch, a metal rod with a convex tip. A simple punch sold with the grommets, can be struck with a hammer to set the grommet, it can be set with an electronic, pneumatic, or gas-powered machine. There are dedicated grommet presses with punch and anvil, as shown in the picture, ranging from inexpensive to better-quality tools, which are somewhat faster to use, they are used to strengthen holes. The grommet prevents the cord from tearing through the hole, thereby providing structural integrity. Small grommets are called eyelets when used in clothing or crafting. Eyelets may be used purely decoratively for crafting.
When used in sailing and various other applications, they are called cringles. Sometimes field workers refer to them as grunyons. If metal or another hard material has a hole made in it, the hole will have sharp edges. Electrical wires, rope, lacings, or other soft vulnerable material passing through the hole can become abraded or cut, or electrical insulation may break due to repeated flexing at the exit point. Rubber, plastic or plastic coated metal grommets are used to avoid this; the grommet could protect the wiring/cabling from contamination from dirt, water, etc. The smooth and sometimes soft inner surface of the grommet shields the wire from damage. Grommets are used whenever wires pass through punched/drilled sheet metal or plastic casings for this reason. Molded and continuous strip grommets known as edge grommets, are manufactured in a wide variety of sizes and lengths expressly for this purpose. Two-piece hard plastic devices are available which grip the wire that passes through; these are called strain relief bushings and are used to insulate and protect power cords where they enter panels.
Preventing a tug or twist on the wire from stressing the electrical connections inside the connected equipment. Sleeved grommets have a flexible extension tapered or moulded to flex towards the free end in order to reduce fracturing of electrical insulation. Grommets made of rubber or other elastic material are used to minimize the transmission of vibration, they were used for mounting shock-sensitive computer disk drives in equipment subject to vibration or jarring, but are not used with more robust modern drives. The screws that hold the drive in place pass through grommets that decouple it acoustically from the chassis. Grommets are used in a similar way to acoustically isolate electronic circuit components that are susceptible to microphonism caused by mechanical vibration or jarring. In chronic cases of otitis media with effusions present for months, surgery is sometimes performed to insert a grommet, called a "tympanostomy tube" into the eardrum to allow air to pass through into the middle ear, thus release any pressure buildup and help clear excess fluid within.
This is a correcting measure for a patulous Eustachian tube. Blind rivet Cable grommet Cringle Shoulder washer Media related to Grommets at Wikimedia Commons The dictionary definition of grommet at Wiktionary
Pompeii
Pompeii was an ancient Roman city near modern Naples in the Campania region of Italy, in the territory of the comune of Pompei. Pompeii, along with Herculaneum and many villas in the surrounding area, was buried under 4 to 6 m of volcanic ash and pumice in the eruption of Mount Vesuvius in AD 79. Volcanic ash buried inhabitants who did not escape the lethal effects of the earthquake and eruption. Preserved under the ash, the excavated city offers a unique snapshot of Roman life, frozen at the moment it was buried and providing an extraordinarily detailed insight into the everyday life of its inhabitants. Organic remains, including wooden objects and human bodies, were entombed in the ash and decayed away, making natural molds; the numerous graffiti carved on the walls and inside rooms provides a wealth of examples of the lost Vulgar Latin spoken colloquially, contrasting with the formal language of the classical writers. Pompeii is a UNESCO World Heritage Site status and is one of the most popular tourist attractions in Italy, with 2.5 million visitors every year.
Excavations recommenced in several unexplored areas of the city, in 2018 new discoveries were reported. Pompeii in Latin is a second declension plural noun. According to Theodor Kraus, "The root of the word Pompeii would appear to be the Oscan word for the number five, which suggests that either the community consisted of five hamlets or it was settled by a family group." The ruins of Pompeii are located near the modern town of Pompei and about 8 km away from Mount Vesuvius. It stands on a spur about 40 m above sea level formed by an ancient lava flow to the north of the mouth of the Sarno River. Three sheets of sediment from large landslides lie on top of the lava triggered by extended rainfall. Today, Pompeii is some distance inland, it covered a total of 64 to 67 hectares and was home to 11,000 to 11,500 people, on the basis of household counts. The first stable settlements on the site date back to the 8th century BC when the Oscans, a people of central Italy, founded five villages in the area.
With the arrival of the Greeks in Campania from around 740 BC Pompeii entered into the orbit of the Hellenic people and the most important building of this period is the Doric Temple, built not near the centre, but in a more isolated position in what would become the Triangular Forum, as the Greeks wanted to control just the streets and the port. At the same time the cult of Apollo was introduced. Greek and Phoenician sailors used the location as a safe port. Around the 6th century BC, it merged into a single community on the important crossroad between Cumae and Stabiae and was surrounded by a tufa city wall, it began to flourish and the first maritime trade started with the construction of a small port near the mouth of the river. The earliest settlement was focussed in regions VII and VIII of the town as identified from stratigraphy below the Samnite and Roman buildings. 524 BC saw the arrival and settlement of the Etruscans in the area including Pompeii, finding in the river Sarno a communication route between the sea and the interior.
To the Greeks, the Etruscans did not conquer the city militarily, but controlled it and Pompeii enjoyed a sort of autonomy. Pompeii became a member of the Etruscan League of cities. Recent excavations have shown the presence of a 6th-century BC necropolis. Under the Etruscans a primitive forum or simple market square was built, as well as the temple of Apollo, in both of which objects including fragments of bucchero were found by Maiuri. Several houses were built with typical of this people; the city wall was strengthened in the early 5th century BC with two façades of thin, vertically set, slabs of Sarno limestone some 4 m apart filled with earth. In 474 BC the Greek city of Cumae, allied with Syracuse, conquered the Etruscans definitively at the Battle of Cumae and gained control of the area; the period between about 450–375 BC witnessed large areas of the city being abandoned while important sanctuaries such as the Temple of Apollo show a sudden lack of votive material remains. The Samnites, people coming from the areas of Abruzzo and Molise, allies of the Romans, conquered Greek Cumae between 423 and 420 BC and it is that in advance, all the surrounding territory, including Pompeii, was conquered around 424 BC.
The new rulers imposed their architecture and enlarged the town. From 343 BC the first Roman army entered the Campanian plain bringing with it the customs and traditions of Rome and in the Roman war against the Latins the Samnites were faithful to Rome. Pompeii, although governed by the Samnites, entered in effect in the Roman orbit, to which it remained faithful during the third Samnite war and in the war against Pyrrhus; the city walls were reinforced in Sarno stone in the early 3rd century BC. It formed the basis for the visible walls with an outer wall of rectangular limestone blocks as an enormous terrace wall supporting a large agger, or earth embankment, behind it. After the Samnite Wars from 290 BC, Pompeii was forced to accept the status of socii of Rome, however and administrative autonomy. From the outbreak of the Second Punic War in which Pompeii remained faithful to Rome, an addit
Toner
Toner is a powder mixture used in laser printers and photocopiers to form the printed text and images on the paper, in general through a toner cartridge. Granulated plastic, early mixtures only added carbon powder and iron oxide, however mixtures have since been developed containing polypropylene, fumed silica, various minerals for triboelectrification. Toner using plant-derived plastic exists as an alternative to petroleum plastic. Toner particles are melted by the heat of the fuser, are thus bonded to the paper. In earlier photocopiers, this low-cost carbon toner was poured by the user from a bottle into a reservoir in the machine. Copiers, laser printers from the first 1984 Hewlett-Packard LaserJet, feed directly from a sealed toner cartridge. Laser toner cartridges for use in color copiers and printers come in sets of cyan, magenta and black, allowing a large color gamut to be generated by mixing; the specific polymer used varies by manufacturer but can be a styrene acrylate copolymer, a polyester resin, a styrene butadiene copolymer, or a few other special polymers.
Toner formulations vary from manufacturer to manufacturer and from machine to machine. Formulation, granule size and melting point vary the most; the particle size of toner averaged 14–16 micrometres or greater. To improve image resolution, particle size was reduced reaching about 8–10 micrometers for 600 dots per inch resolution. Further reductions in particle size producing further improvements in resolution are being developed through the application of new technologies such as Emulsion-Aggregation. Toner manufacturers maintain a quality control standard for particle size distribution in order to produce a powder suitable for use in their printers. Toner has traditionally been made by compounding the ingredients and creating a slab, broken or pelletized turned into a fine powder with a controlled particle size range by air jet milling; this process results in toner granules with aspherical shapes. To get a finer print, some companies are using a chemical process to grow toner particles from molecular reagents.
This results in more uniform size and shapes of toner particles. The smaller, uniform shapes permit more accurate colour reproduction and more efficient toner use. Toner can be washed off skin and garments with cold water. Hot or warm water softens the toner. Toner fused to skin wears off, or can be removed using an abrasive hand cleaner. Toner fused to clothing cannot be removed. Toner particles have electrostatic properties by design and can develop static-electric charges when they rub against other particles, objects, or the interiors of transport systems and vacuum cleaner hoses; because of this and the small particle size, toner should not be vacuumed with a conventional home vacuum cleaner. Static discharge from charged toner particles theoretically may ignite dust in the vacuum cleaner bag or create a small explosion if sufficient toner is airborne. Toner particles are so fine that they are poorly filtered by household vacuum cleaner filter bags and can blow through the vacuum motor into the room.
So they can cause overheating by clogging the motor filter and short circuit by their electric conductivity when they melt inside the motor. If toner spills into the laser printer, a special type of vacuum cleaner with an electrically conductive hose and a high efficiency filter may be needed for effective cleaning; these are called electrostatic toner vacuums. Similar HEPA-filter equipped vacuums should be used for clean-up of larger toner spills. Unfused toner is cleaned from most water-washable clothing; because toner is a wax or plastic powder with a low melting temperature, it must be kept cold while cleaning. The washing machine should be filled with cold water before adding the garment. Two complete wash cycles improve the chances of success; the first may use hand wash dish detergent, the second may use regular laundry detergent. Residual toner floating in the rinse water of the first cycle will remain in the garment and may cause permanent graying. A clothes dryer or iron should not be used.
As a fine powder, toner can remain suspended in the air for some period, is considered to have health effects comparable to inert dust. It can be an irritant to people with respiratory conditions such as asthma or bronchitis. Following studies on bacteria in the 1970s that raised concerns about health effects resulting from pyrrole, a contaminant created during manufacture of the carbon black used in black toner, manufacturing processes were changed to eliminate pyrrole from the finished product. Research by the Queensland University of Technology has indicated that some laser printers emit submicrometer particles which have been associated in other environmental studies with respiratory diseases. Muhle et al. reported that the responses to chronically inhaled copying toner, a plastic dust pigmented with carbon black, titanium dioxide and silica, were similar qualitatively to titanium dioxide and diesel exhaust. Carbon black, one of the components of toner, is classified as "possibly carcinogenic" by the IARC.
A study at the University of Rostock has found that the microscopic particles in toner are carcinogenic, similar to asbestos. Several technicians, working with printers and copiers on a daily basis were observed for several years, they showed increased lung problems. This confirms previous research published in 2006; the toner container can be a simple pack, for toner storage and transportation, or further, a consumable component of the printer. The most common way to consume toner is with a ton
Front curtain
A front curtain known as a house curtain, act curtain, grand drape, main drape or main rag, is the stage curtain or curtains at the front of a theatrical stage. The front curtain is opened at the beginning of a performance to reveal the stage set and closed during intermissions and at the end of a performance; the most common material for the front curtain is a heavy velour material with pleated fullness sewn into the fabric to create a more opulent appearance. There are several types of house curtains, which vary in construction and cost. Depending on a curtain's type, its fabric may be flat or pleated, it may drape, hang, or do both; some types open by rising into the fly space above the stage. Some require mechanical power to operate whereas others may be operated by a person, by pulling an operating line or directly pulling the curtains; the Austrian curtain or Austrian drape called a puff curtain, has multiple vertical lines spaced evenly across the width of the fabric, a thin satin, charmeuse, or chiffon material that bunches well.
Each line runs through a pulley at the top of the curtain and horizontally to a common head block. The lines descend from the head block to a mechanical winch, used to raise the curtain. A winch is necessary to perform this function as the curtain would otherwise be too heavy for one person to raise; as the winch turns, the curtain rises and is collected in a series of swags, which are accentuated by horizontal pleats sewn into the curtain from top to bottom, thereby giving it both vertical and horizontal fullness. Austrian curtains reached their height of popularity in the mid twentieth century, they are considered visually attractive and simple to operate and require little fly space, but have complicated rigging and are expensive. A variation on the Austrian is the waterfall curtain: in this version, instead of horizontal festoons, the curtain has vertical pleats like a traditional theater curtain, but it still gathers from the bottom in a number of swags; the waterfall has a pipe batten along the bottom edge to ensure the lines rise evenly.
A brail curtain or drape appears as a pleated panel much like a traveler curtain when in the lowered position. It is rigged, however, as an Austrian curtain: the multiple lines leading through rings sewn to along the seams on the back side of the curtain cause the fabric to gather along the bottom in swags as the curtain is raised, it has a faster action than a traveler curtain, like an Austrian it requires little fly space. An olio drop called an olio curtain, roll drop, or an olio, consists of a single large canvas called a drop, attached at the bottom to a long rigid tube; the canvas is decorated with a mural. Olio curtains were popular in vaudeville theatre as they require a minimum of overhead space, were simple to construct, in most cases could be operated by a single person; each end of the rigid tube of the drop has a single coil of rope called an "operating line" wrapped around it. One end of each operating line is secured to the fly space; the line descends from the fly space and loops around the tube once rises back up to the fly space and through a pulley.
The other end of the line attaches to a counterbalance in the form of sandbags before running back down to the stage floor. When the two lines are pulled, the sandbags descend in unison, causing the tube to rotate and rise, thereby rolling up the canvas onto the tube and revealing the stage. An olio requires a sturdy roll tube to prevent sagging; the larger the tube diameter, the more it will descend when the ropes are loosened. The most common type of front curtain is called a draw curtain, traveler curtain, bi-parting curtain, or just traveler. Traveler curtains remain at a fixed elevation and open and close horizontally, breaking in the middle, require a minimum of fly space, they always hang and therefore are referred to as "drapes". The curtains are made of velvet and decorated with a series of vertical box pleats along the top edge, they are the least costly kind of theater curtain to construct and are simple to operate. The tableau, tab, or tabbed curtain called opera drapes, though iconic of the theater setting, is the rarest of curtains to be employed on the stage.
It consists of two overlapping panels secured along the top to a batten, with the lower onstage corners or center points of the panel edges attached to lines or cables. These lines run through series of rings behind each curtain diagonally, through pulleys in the batten and down to the floor; when the cord is pulled, the fabric is lifted diagonally away from the center. In this position, it does not clear the stage, instead creating a frilled tent-like viewing frame for the performance– it is because of this tendency to limit the audience's view that it is used except in small venues. However, as the top of the curtain never moves, it requires no track and as the curtain itself is never raised, neither does it require any sandbag counterweights; the Venetian curtain known as a profile or contour curtain, has multiple vertical lines distributed across the length of the single panel of fabric, made with as much as 200% fullness and must be thin and soft so it gathers well. The curtain is opened by pulling on the lines.
Each line is independently operated, making it possible to control the shape and height
Laser printing
Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by passing a laser beam back and forth over a negatively charged cylinder called a "drum" to define a differentially charged image; the drum selectively collects electrically charged powdered ink, transfers the image to paper, heated in order to permanently fuse the text, imagery, or both. As with digital photocopiers, laser printers employ a xerographic printing process. However, laser printing differs from analog photocopiers in that the image is produced by the direct scanning of the medium across the printer's photoreceptor; this enables laser printing to copy images more than most photocopiers. Invented at Xerox PARC in the 1970s, laser printers were introduced for the office and home markets in subsequent years by IBM, Xerox, Hewlett-Packard and many others. Over the decades and speed have increased as price has fallen, the once cutting-edge printing devices are now ubiquitous. In the 1960s, the Xerox Corporation held a dominant position in the photocopier market.
In 1969, Gary Starkweather, who worked in Xerox's product development department, had the idea of using a laser beam to "draw" an image of what was to be copied directly onto the copier drum. After transferring to the formed Palo Alto Research Center in 1971, Starkweather adapted a Xerox 7000 copier to create SLOT. In 1972, Starkweather worked with Butler Lampson and Ronald Rider to add a control system and character generator, resulting in a printer called EARS —which became the Xerox 9700 laser printer. 1973: The Xerox 1200 was "the first commercial laser printer." A Xerox 2012 lookback described it as the "first commercial non-impact Xerographic printer for computer output." Input was either directly from a mainframe computer. The technology came from the Xerox 3600 copier. 1976: The first commercial implementation of a laser printer was the IBM 3800 in 1976. It was designed for data centers; the IBM 3800 was used for high-volume printing on continuous stationery, achieved speeds of 215 pages per minute, at a resolution of 240 dots per inch.
Over 8,000 of these printers were sold. 1977: The Xerox 9700 was brought to market in 1977. Unlike the IBM 3800, the Xerox 9700 was not targeted to replace any particular existing printers; the Xerox 9700 excelled at printing high-value documents on cut-sheet paper with varying content. 1979: In 1979, inspired by the Xerox 9700's commercial success, Japanese camera and optics company, developed a low-cost, desktop laser printer: the Canon LBP-10. Canon began work on a much-improved print engine, the Canon CX, resulting in the LBP-CX printer. Having no experience in selling to computer users, Canon sought partnerships with three Silicon Valley companies: Diablo Data Systems, Hewlett-Packard, Apple Computer. 1981: The first laser printer designed for office use reached market in 1981: the Xerox Star 8010. The system used a desktop metaphor, unsurpassed in commercial sales, until the Apple Macintosh. Although it was innovative, the Star workstation was a prohibitively expensive system, affordable only to a fraction of the businesses and institutions at which it was targeted.
1984: The first laser printer intended for mass-market sales was the HP LaserJet, released in 1984. The LaserJet was followed by printers from Brother Industries, IBM, others. First-generation machines had large photosensitive drums, of circumference greater than the loaded paper's length. Once faster-recovery coatings were developed, the drums could touch the paper multiple times in a pass, therefore be smaller in diameter. 1985: Apple introduced the LaserWriter, but used the newly released PostScript page-description language. Up until this point, each manufacturer used its own proprietary page-description language, making the supporting software complex and expensive. PostScript allowed the use of text, graphics and color independent of the printer's brand or resolution. PageMaker, written by Aldus for the Macintosh and LaserWriter, was released in 1985 and the combination became popular for desktop publishing. Laser printers brought exceptionally fast and high-quality text printing in multiple fonts on a page, to the business and consumer markets.
No other available printer during this era could offer this combination of features. 1995: Xerox ran magazine print ads headlined "Who invented the laser printer?" and answered "it's Xerox." A laser beam projects an image of the page to be printed onto an electrically charged, selenium-coated, cylindrical drum. Photoconductivity allows the charged electrons to fall away from the areas exposed to light. Powdered ink particles are electrostatically attracted to the charged areas of the drum that have not been laser-beamed; the drum transfers the image onto paper by direct contact. The paper is passed onto a finisher, which uses heat to fuse the toner that represents the image onto the paper. There are seven steps involved in
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Media related to Curtains at Wikimedia Commons
