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134-643: The LaserWriter is a laser printer with built-in PostScript interpreter sold by Apple, Inc. from 1985 to 1988. It was one of the first laser printers available to the mass market. In combination with WYSIWYG publishing software like PageMaker that operated on top of the graphical user interface of Macintosh computers, the LaserWriter was a key component at the beginning of the desktop publishing revolution. Laser printing traces its history to efforts by Gary Starkweather at Xerox in 1969, which resulted in

268-574: A DC bias on the drum surface to ensure a uniform negative potential. 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 . A laser printer uses

402-558: A Ricoh engine for $ 12,800 in 1983. Sales of the non-networked product were unsurprisingly poor. In 1983, Canon introduced the LBP-CX, a desktop laser printer engine using a laser diode and featuring an output resolution of 300 dpi. In 1984, HP released the first commercially available system based on the LBP-CX, the HP LaserJet . Steve Jobs of Apple Computer had seen the LBP-CX while negotiating for supplies of 3.5" floppy disk drives for

536-412: A buffer underrun (where the laser reaches a point on the page before it has the dots to draw there), a laser printer typically needs enough raster memory to hold the bitmap image of an entire page. Memory requirements increase with the square of the dots per inch , so 600 dpi requires a minimum of 4 megabytes for monochrome, and 16 megabytes for color (still at 600 dpi). For fully graphical output using

670-481: A corona wire positioned parallel to the drum or, in more recent printers, 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. An AC bias voltage is applied to the primary charge roller to remove any residual charges left by previous images. The roller will also apply

804-456: A double-blind test, reviewers generally preferred the output produced using third-party ink over OEM ink. In general, OEM inks have undergone significant system reliability testing with the cartridge and print-head materials, whereas R&D efforts on third-party ink material compatibility are likely to be significantly less. Some inkjet manufacturers have tried to prevent cartridges being refilled using various schemes including fitting chips to

938-637: A raster image , they nonetheless outperform the 1984 LaserJet in nearly all situations. 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. The cost of this technology depends on

1072-524: A "reference model" (but with customization for the Linotronic's different video interface, plus the necessary implementation of "banding" and a hard drive frame buffer and font storage mechanism). Indeed, the PostScript language itself was concurrently enhanced and extended to support these high-resolution "banding" devices (as contrasted to the lower resolution "framing" devices, such as the LaserWriter, in which

1206-433: A combination of factors, including the cost of paper, toner, drum replacement, as well as the replacement of other items 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. Duplex printing (printing on both sides of the paper) can halve paper costs and reduce filing volumes, albeit at

1340-563: A commercial system called the Xerox 9700 . IBM followed this with the IBM 3800 system in 1976. Both machines were large, room-filling devices handling the combined output of many users. During the mid-1970s, Canon started working on similar machines, and partnered with Hewlett-Packard to produce 1980's HP 2680, which filled only part of a room. Other copier companies also started development of similar systems. HP introduced their first desktop model with

1474-591: A considerable amount of ink, and will drive printing costs higher especially if the printer is unused for long periods. If an inkjet head becomes clogged, third-party ink solvents/head cleaners and replacement heads are available in some cases. The cost of such items may be less expensive compared to a transfer unit for a laser printer, but the laser printer unit has a much longer lifetime between required maintenance. Many inkjet printer models now have permanently installed heads, which cannot be economically replaced if they become irreversibly clogged, resulting in scrapping of

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1608-425: A continuous inkjet ink (CIJ) in the 1971 patent US3596285A states " The preferred ink is characterized by viscosity and surface tension characteristics such that the liquid will be maintained over span under the force with which it is moving in bridge or stream. Implicit in such requirement is that the pressure applied to the ink in formation of said stream is sufficient to form a jet and to impart enough energy to carry

1742-420: A control system and character generator, resulting in a printer called EARS (Ethernet, Alto Research character generator, Scanned laser output terminal)—which later became the Xerox 9700 laser printer. In 1976, the first commercial implementation of a laser printer, the IBM 3800 , was released. It was designed for data centers , where it replaced line printers attached to mainframe computers . The IBM 3800

1876-469: A damaged or clogged print head is only a minor problem: the user can simply buy a new cartridge. Hewlett-Packard has traditionally favored the disposable print head, as did Canon in its early models. This type of construction can also be seen as an effort by printer manufacturers to stem third party ink cartridge assembly replacements, as these would-be suppliers do not have the ability to manufacture specialized print heads. An intermediate method does exist:

2010-478: A disposable ink tank connected to a disposable head, which is replaced infrequently (perhaps every tenth ink tank or so). Most high-volume Hewlett-Packard inkjet printers use this setup, with the disposable print heads used on lower volume models. A similar approach is used by Kodak , where the printhead intended for permanent use is nevertheless inexpensive and can be replaced by the user. Canon now uses (in most models) replaceable print heads which are designed to last

2144-429: A heated transfer roller instead of a fuser, that melts the charged ink particles before applying them to the paper. Color laser transfer printers are designed to produce transfer media which are transfer sheets designed to be applied by means of a heat press . These transfers are typically used to make custom T-shirts or custom logo products with corporate or team logos on them. 2-part Color laser transfers are part of

2278-405: A laser because lasers are able to form highly focused, precise, and intense beams of light, especially over the short distances inside of a printer. The laser is aimed at a rotating polygonal mirror which directs the light beam through a system of lenses and mirrors onto the photoreceptor drum, writing pixels at rates up to sixty-five million times per second. The drum continues to rotate during

2412-428: A laser printer is somewhat delicate and, once damaged, often impossible to repair. The drum, in particular, is a critical component: it must not be left exposed to ambient light for more than a few hours, as light is what causes it to lose its charge and will eventually wear it out. Anything that interferes with the operation of the laser such as a scrap of torn paper may prevent the laser from discharging some portion of

2546-414: A laser. "Exposing" is also known as "writing" in some documentation. As the drums rotate, toner is continuously applied in a 15- micron -thick layer to the developer roll . The surface of the photoreceptor with the latent image is exposed to the toner-covered developer roll. Toner consists of fine particles of dry plastic powder mixed with carbon black or coloring agents. The toner particles are given

2680-701: A market in which the Mac is still important. The LaserWriter was the first major printer designed by Apple to use the new Snow White design language created by Frog Design . It also continued a departure from the beige color that characterized the Apple and Macintosh products to that time by using the same brighter, creamy off-white color first introduced with the Apple IIc and Apple Scribe Printer 8 months earlier. In that regard it and its successors stood out among all of Apple's Macintosh product offerings until 1987, when Apple adopted

2814-416: A mechanism to reapply moisture to the printhead. Typically there is no separate supply of pure ink-free solvent available to do this job, and so instead the ink itself is used to remoisten the printhead. The printer attempts to fire all nozzles at once, and as the ink sprays out, some of it wicks across the printhead to the dry channels and partially softens the hardened ink. After spraying, a rubber wiper blade

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2948-535: A nearly invisible dot raster , for the purpose of traceability. The dots are yellow and about 0.1 mm (0.0039 in) in size, with a raster of about 1 mm (0.039 in). This is purportedly the result of a deal between the US government and printer manufacturers to help track counterfeiters . 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

3082-445: A negative charge inside the toner cartridge , and as they emerge onto the developer drum they are electrostatically attracted to the photoreceptor's latent image (the areas on the surface of the drum which had been struck by the laser). Because negative charges repel each other, the negatively charged toner particles will not adhere to the drum where the negative charge (imparted previously by the charge roller) remains. A sheet of paper

3216-513: A page description language, a minimum of 1 megabyte of memory is needed to store an entire monochrome letter - or 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 × 11 sheet of paper has 0.25-inch (6.4 mm) margins, reducing the printable area to 8.0 by 10.5 inches (200 mm × 270 mm), or 84 square inches. 84 sq/in × 90,000 dots per sq/in = 7,560,000 dots. 1 megabyte = 1,048,576 bytes, or 8,388,608 bits, which

3350-462: A page, to the business and home markets. No other commonly available printer during this era could also offer this combination of features. A laser beam projects an image of the page to be printed onto an electrically charged, photoconductive , rotating, cylindrical drum. Photoconductivity conducts charged electrons away from the areas exposed to laser light. Powdered ink ( toner ) particles are then electrostatically attracted to remaining areas of

3484-414: A slower page-printing speed because of the longer paper path. 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. In a commercial environment such as an office, it is becoming increasingly common for businesses to use external software that increases the performance and efficiency of laser printers in

3618-418: A stream into droplets. Optimal drop sizes of 0.004 inches (0.10 mm) require an inkjet nozzle size of about 0.003 inches (0.076 mm). Fluids with surface tension may be water based, wax or oil based and even melted metal alloys. Most drops can be electrically charged. There are two main technologies in use in contemporary inkjet printers: continuous (CIJ) and drop-on-demand (DOD). Continuous inkjet means

3752-411: A suitable interpreter and then sent to a software rasterizer program, all inside the printer. To support this, the LaserWriter featured a Motorola 68000 CPU running at 12  MHz , 512 KB of workspace RAM , and a 1 MB frame buffer. At introduction, the LaserWriter had the most processing power in Apple's product line—more than the 8 MHz Macintosh. As a result, the LaserWriter

3886-403: A two-step process whereby the color laser printers use colored toner (dry ink), typically cyan , magenta , yellow , and black ( CMYK ); however, newer printers designed to print on dark T-shirts utilize a special white toner allowing them to make transfers for dark garments or dark business products. The CMYK color printing process allows for millions of colors to be faithfully represented by

4020-539: A unifying warm gray color they called Platinum across its entire product line, which was to last for over a decade. The LaserWriter was also the first peripheral to use the LocalTalk connector and Apple's unified round AppleTalk Connector Family, which allowed any variety of mechanical networking systems to be plugged into the ports on the computers or printers. A common solution was the 3rd party PhoneNET which used conventional telephone cables for networking. Apple's RIP

4154-408: A variety of industrial applications ranging from signage, textiles, optical media, ceramics and 3-D printing into biomedical applications and conductive circuitry. Leading companies and innovators in hardware include HP, Epson, Canon, Konica Minolta, FujiFilm, EFi, Durst, Brother, Roland, Mimaki, Mutoh and many others worldwide. Many "intelligent" ink cartridges contain a microchip that communicates

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4288-449: Is a type of computer printing that recreates a digital image by propelling droplets of ink onto paper and plastic substrates. Inkjet printers were the most commonly used type of printer in 2008, and range from small inexpensive consumer models to expensive professional machines. By 2019, laser printers outsold inkjet printers by nearly a 2:1 ratio, 9.6% vs 5.1% of all computer peripherals. The concept of inkjet printing originated in

4422-434: Is coated with selenium , or more recently, with an organic photoconductor made of N-vinylcarbazole , an organic monomer . There are typically seven steps involved in the process, detailed in the sections below. The document to be printed is encoded in a page description language such as PostScript, Printer Command Language (PCL), or Open XML Paper Specification (OpenXPS). The raster image processor (RIP) converts

4556-492: Is generally shorter (although UV-resistant inks are available) than those produced with solvent-based inkjets; however, so-called "archival inks" have been produced for use in aqueous-based machines which offer extended life. In addition to smearing, gradual fading of many inks can be a problem over time. Print lifetime is highly dependent on the quality and formulation of the ink. The earliest inkjet printers, intended for home and small office applications, used dye-based inks. Even

4690-403: Is ink drying on the printhead's nozzles, causing the pigments and dyes to dry out and form a solid block of hardened mass that plugs the microscopic ink passageways. Most printers attempt to prevent this drying from occurring by covering the printhead nozzles with a rubber cap when the printer is not in use. Abrupt power losses, or unplugging the printer before it has capped the printhead, can cause

4824-455: 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 color printer, each of the four CMYK 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-color letter-size or A4-size page at 300 dpi. During the 1980s, memory chips were still very expensive, which

4958-741: Is limited by their resolution (typically 600–1200 dpi) and their use of just four color toners. They often have trouble printing large areas of the same or subtle gradations of color. Inkjet printers designed for printing photos can produce much higher quality color images. An in-depth comparison of inkjet and laser printers suggest that laser printers are the ideal choice for a high quality, volume printer, while inkjet printers tend to focus on large-format printers and household units. Laser printers offer more precise edging and in-depth monochromatic color. In addition, color laser printers are much faster than inkjet printers, although being generally larger and bulkier. Many modern color laser printers mark printouts by

5092-461: 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 very short contact time. As the drum completes a revolution, it is exposed to an electrically neutral soft plastic blade that cleans any remaining toner from

5226-404: Is now possible to buy inexpensive devices to reliably reset such cartridges to report themselves as full, so that they may be refilled many times. The very narrow inkjet nozzles are prone to clogging. The ink consumed in cleaning them—either during cleaning invoked by the user, or in many cases, performed automatically by the printer on a routine schedule—can account for a significant proportion of

5360-408: 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. Some printers use a very thin flexible metal foil roller, so there is less thermal mass to be heated and the fuser can more quickly reach operating temperature . If paper moves through the fuser more slowly, there

5494-408: Is swept across the printhead to spread the moisture evenly across the printhead, and all jets are again fired to dislodge any ink clumps blocking the channels. Some printers use a supplemental air-suction pump, using the rubber capping station to suck ink through a severely clogged cartridge. The suction pump mechanism is frequently driven by the page feed stepper motor : it is connected to the end of

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5628-440: Is then rolled under the photoreceptor drum, which has been coated with a pattern of toner particles in the exact places where the laser struck it moments before. The toner particles have a very weak attraction to both the drum and the paper, but the bond to the drum is weaker and the particles transfer once again, this time from the drum's surface to the paper's surface. Some machines also use a positively charged "transfer roller" on

5762-437: Is too high, the toner will not fuse well to the paper and may flake off after printing. If the fuser is too hot, the plastic component of the toner may smear, causing the printed text to look like it is wet or smudged, or may cause the melted toner to soak through the paper to the backside. Different manufacturers claim that their toners are specifically developed for their printers and that other toner formulations may not match

5896-566: Is very bad for printer ink cartridges. The user should prevent the printer becoming too hot or too chilly as the cartridges can dry up. For lasting printer efficiency, the user should ensure the area has a regular and steady temperature level. Inkjets use solvent-based inks which have much shorter expiration dates compared to laser toner, which has an indefinite shelf life. Inkjet printers tend to clog if not used regularly, whereas laser printers are much more tolerant of intermittent use. Inkjet printers require periodical head cleaning, which consumes

6030-438: Is water-soluble, care must be taken with inkjet-printed documents to avoid even the smallest drop of moisture, which can cause severe "blurring" or "running". In extreme cases, even sweaty fingertips during hot humid weather could cause low-quality inks to smear. Similarly, water-based highlighter markers can blur inkjet-printed documents and discolor the highlighter's tip. The lifetime of inkjet prints produced using aqueous inks

6164-499: Is why entry-level laser printers in that era always came with four-digit suggested retail prices in US dollars. The primitive microprocessors in early personal computers were so underpowered and insufficient for graphics work that attached laser printers usually had more onboard processing power. Memory prices later decreased significantly, while rapid improvements in the performance of PCs and peripheral cables (most importantly, SCSI ) enabled

6298-414: The HP LaserJet and other non-Postscript printers. Paired with the program Aldus PageMaker , the LaserWriter gave the layout editor an exact replica of the printed page. The LaserWriter offered a generally faithful proofing tool for preparing documents for quantity publication, and could print smaller quantities directly. The Mac platform quickly gained the favor of the emerging desktop-publishing industry,

6432-425: The "frame buffer", for the lowest resolution devices, 300 dpi), as more than 300 dpi of course required more RAM, and some LaserWriters were able to change between 300 dpi and 600 dpi, depending upon how much RAM was installed. 600 dpi, for example, required 6 MB of RAM, but 8 MB of RAM was more commonly found. At this point, Apple's LaserWriters were employing generic non-parity RAM, whereas HP's LaserJets, especially

6566-523: The 'ink' can now also comprise solder paste in PCB assembly , or living cells, for creating biosensors and for tissue engineering . Images produced on inkjet printers are sometimes sold under trade names such as Digigraph , Iris prints , giclée , and Cromalin . Inkjet-printed fine art reproductions are commonly sold under such trade names to imply a higher-quality product and avoid association with everyday printing. Fluid surface tension naturally pulls

6700-644: 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 recently formed Palo Alto Research Center (Xerox PARC) in 1971, Starkweather adapted a Xerox 7000 copier to make SLOT (Scanned Laser Output Terminal). In 1972, Starkweather worked with Butler Lampson and Ronald Rider to add

6834-475: The 20th century, and the technology was first extensively developed in the early 1950s. While working at Canon in Japan, Ichiro Endo suggested the idea for a "bubble jet" printer, while around the same time Jon Vaught at Hewlett-Packard (HP) was developing a similar idea. In the late 1970s, inkjet printers that could reproduce digital images generated by computers were developed, mainly by Epson , HP and Canon. In

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6968-529: The HP model. However, the LaserWriter featured AppleTalk support that allowed the printer to be shared among as many as sixteen Macs, meaning that its per-user price could fall to under $ 450, far less expensive than HP's less-advanced model. The combination of the LaserWriter, PostScript, PageMaker and the Mac's GUI and built-in AppleTalk networking would ultimately transform the landscape of computer desktop publishing. At

7102-535: The LaserWriter II was designed to allow for complete replacement of the computer circuit board that operates the printer. Across all the different models, the print engine was the same. Three years later in 1991, two updated versions of the LaserWriter II were produced. To deliver higher performance, Apple eventually switched from the 68000 series to the Am29000 series of processors to drive later models, starting with

7236-458: The LaserWriter to the Mac over an RS-422 serial port. At 230.4 kbit / s LocalTalk was slower than the Centronics PC parallel interface, but allowed several computers to share a single LaserWriter. PostScript enabled the LaserWriter to print complex pages containing high-resolution bitmap graphics , outline fonts , and vector illustrations. The LaserWriter could print more complex layouts than

7370-468: The Officejet Pro 8620 and HP's Pagewide series. The disposable head philosophy uses a print head which is supplied as a part of a replaceable ink cartridge . Every time a cartridge is exhausted, the entire cartridge and print head are replaced with a new one. This adds to the cost of consumables and makes it more difficult to manufacture a high-precision head at a reasonable cost, but also means that

7504-497: The Personal LaserWriter NTR in 1992. Laser printing The laser printer was invented at Xerox PARC in the 1970s. Laser printers were introduced for the office and then home markets in subsequent years by IBM , Canon , Xerox, Apple , Hewlett-Packard and many others. Over the decades, quality and speed have increased as prices have decreased, and the once cutting-edge printing devices are now ubiquitous. In

7638-663: The Pixelmaster color printer with solid ink using Thermojet technology. This technology consists of a tubular single nozzle acoustical wave drop generator invented originally by Steven Zoltan in 1972 with a glass nozzle and improved by the Howtek inkjet engineer in 1984 with a Tefzel molded nozzle to remove unwanted fluid frequencies. The emerging ink jet material deposition market also uses inkjet technologies, typically printheads using piezoelectric crystals, to deposit materials directly on substrates. The technology has been extended and

7772-480: The advantage of practically no warm up time, and often lower cost per page. However, low-cost laser printers can have lower per-page costs, at least for black-and-white printing, and possibly for color. For some inkjet printers, monochrome ink sets are available either from the printer manufacturer or from third-party suppliers. These allow the inkjet printer to compete with the silver-based photographic papers traditionally used in black-and-white photography, and provide

7906-413: The backside of the paper to help pull the negatively charged toner from the photoreceptor drum to the paper. The paper passes through rollers in the fuser assembly, where temperatures up to 427 °C (801 °F) and pressure are used to permanently bond the toner to the paper. One roller is usually a hollow tube (heat roller) and the other is a rubber-backed roller (pressure roller). A radiant heat lamp

8040-719: The best dye-based inks are not as durable as pigment-based inks, which are now available for many inkjet printers. Many inkjet printers now utilize pigment based inks which are highly water resistant: at least the black ink is often pigment-based. Resin or silicone protected photopaper is widely available at low cost, introducing complete water and mechanical rub resistance for dye and pigment inks. The photopaper itself must be designed for pigment or for dye inks, as pigment particles are too large to be able to penetrate through dye-only photopaper protection layer. The highest-quality inkjet prints are often called " giclée " prints, to distinguish them from less-durable and lower-cost prints. However,

8174-410: The blade allows too much toner to remain on the developer roll, the toner particles might come loose as the roll turns, precipitate onto the paper below, and become bonded to the paper during the fusing process. This will result in a general darkening of the printed page in broad vertical stripes with very soft edges. If the fuser roller does not reach a high enough temperature or if the ambient humidity

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8308-450: The businesses and institutions at which it was targeted. Later, in 1984, the first laser printer intended for mass-market sales, the HP LaserJet , was released; it used the Canon CX engine, controlled by HP software. The LaserJet was quickly followed by printers from Brother Industries , IBM , and others. First-generation machines had large photosensitive drums, of circumference greater than

8442-521: The carrier fluid. Desktop inkjet printers, as used in offices and homes, tend to use aqueous ink based on a mixture of water, glycol and dyes or pigments . These inks are inexpensive to manufacture but difficult to control on the surface of media, often requiring specially coated media. HP inks contain sulfonated polyazo black dye (commonly used for dyeing leather ), nitrates and other compounds. Aqueous inks are mainly used in printers with thermal inkjet heads, as these heads require water to perform

8576-438: The cartridge is empty. The frequent cleaning conducted by some printers can consume quite a bit of ink and has a great impact on cost-per-page determinations. Clogged nozzles can be detected by printing a standard test pattern on the page. Some software workaround methods are known for rerouting printing information from a clogged nozzle to a working nozzle. Ink cartridges have been the traditional method for delivering ink to

8710-640: The cartridges that log how much the cartridge has printed and prevent the operation of a refilled cartridge. The warranty on a printer may not apply if the printer is damaged by the use of non-approved supplies. In the US the Magnuson–Moss Warranty Act is a federal law which states that warrantors cannot require that only brand name parts and supplies be used with their products, as some printer manufacturers imply. However, this would not apply if non-approved items cause damage. Inkjet documents can have poor to excellent archival durability, depending on

8844-538: The chip claims the cartridge is empty, although a researcher who over-rode the system found that in one case he could print up to 38% more good quality pages, even though the chip stated that the cartridge was empty. Third-party ink suppliers sell ink cartridges at significant discounts (at least 10–30% off OEM cartridge prices, sometimes up to 95%, typically averaging around 50%), and also bulk ink and cartridge self-refill kits at even lower prices. Many vendors' "intelligent" ink cartridges have been reverse-engineered . It

8978-494: The development of low-end laser printers which offload rasterization to the sending PC. For such printers, the operating system's print spooler renders the raw bitmap of each page into the PC's system memory at the target resolution, then sends that bitmap directly to the laser (at the expense of slowing down all other programs on the sending PC). The appearance of so-called "dumb" or "host-based" laser printers from NEC made it possible for

9112-415: The drum that have not been laser-beamed. The drum then transfers the image onto paper which is passed through the machine by direct contact. Finally, the paper is passed onto a finisher, which uses heat to instantly fuse the toner that represents the image onto the paper. The laser is typically an aluminium gallium arsenide (AlGaAs) semiconductor laser ), which emits red or infrared light. The drum

9246-422: The drum to pick up excessive toner on the next revolution from the developer roll and causing a repeated but fainter image from the previous revolution to appear down the page. If the toner doctor blade does not ensure that a smooth, even layer of toner is applied to the developer roll, the resulting printout may have white streaks from this in places where the blade has scraped off too much toner. Alternatively, if

9380-419: The drum which were struck by the laser, however, momentarily have no charge, and the toner being pressed against the drum by the toner-coated developer roll in the next step moves from the roll's rubber surface to the charged portions of the surface of the drum. Some non-laser printers ( LED printers ) use an array of light-emitting diodes spanning the width of the page to generate an image, rather than using

9514-406: The drum, causing those areas to appear as white vertical streaks. If the neutral wiper blade fails to remove residual toner from the drum's surface, that toner may circulate on the drum a second time, causing smears on the printed page with each revolution. If the charge roller becomes damaged or does not have enough power, it may fail to adequately negatively charge the surface of the drum, allowing

9648-510: The entire "frame" could be contained within the available RAM ). In most cases, such RAM was fixed in size and was soldered to the logic board. In late PostScript Level 1, and in early PostScript Level 2, the RAM size was made variable and was generally extensible, through plug-in DIMMs, beyond the 2.0 to 2.5 MB minimum (0.5 to 1.0 MB for instructions, depending upon PostScript version, and 1.5 MB minimum for

9782-522: The entire printer. On the other hand, inkjet printer designs which use a disposable printhead usually cost significantly more per page than printers using permanent heads. By contrast, laser printers do not have printheads to clog or replace frequently, and usually can produce many more pages between maintenance intervals. Inkjet printers have traditionally produced better quality output than color laser printers when printing photographic material. Both technologies have improved dramatically over time, although

9916-408: The estimated ink level to the printer; this may cause the printer to display an error message, or incorrectly inform the user that the ink cartridge is empty. In some cases, these messages can be ignored, but some inkjet printers will refuse to print with a cartridge that declares itself empty, to prevent consumers from refilling cartridges. For example, Epson embeds a chip which prevents printing when

10050-459: The exhausted print heads. Compared to earlier consumer-oriented color printers, inkjet printers have a number of advantages. They are quieter in operation than impact dot matrix or daisywheel printers . They can print finer, smoother details through higher resolution. Consumer inkjet printers with photographic print quality are widely available. In comparison to technologies like thermal wax , dye sublimation , and laser printing , inkjets have

10184-436: The flow is pressurized and in a continuous stream. Drop-on-demand means the fluid is expelled from the jet nozzle one drop at a time. This can be done with a mechanical means with a push or some electrical method. A large electrical charge can pull drops out of a nozzle, sound waves can push fluid from a nozzle or a chamber volume expansion can expel a drop. Continuous streaming was investigated first many years ago. Drop-on-demand

10318-439: The four colors. Color printing 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. To permit a high registration accuracy, some color laser printers use a large rotating belt called a "transfer belt". The transfer belt passes in front of all

10452-526: The frequency of drops. DOD may use a single nozzle or thousands of nozzles. One DOD process uses software that directs the heads to apply between zero and eight droplets of ink per dot, only where needed. Inkjet fluid materials have expanded to include pastes, epoxies, hot-melt inks, biological fluids, etc. DOD is very popular and has an interesting history. Mechanical DOD came first, followed by electrical methods including piezoelectric devices and then thermal or heat expansion methods. The earliest reference to

10586-434: The ink tank. The channel is long and narrow to reduce moisture evaporation through the vent tube, but some evaporation still occurs and eventually the ink cartridge dries up from the inside out. To combat this problem, which is especially acute with professional fast-drying solvent inks, many wide-format printer cartridge designs contain the ink in an airtight, collapsible bag that requires no vent. The bag merely shrinks until

10720-447: The ink used in the machine. Inkjet printing head nozzles can be cleaned using specialized solvents, or by soaking in warm distilled water for short periods of time (for water-soluble inks.) The high cost of OEM ink cartridges and the intentional obstacles to refilling them have been addressed by the growth of third-party ink suppliers. Many printer manufacturers discourage customers from using third-party inks, stating that they can damage

10854-571: The ink-expelling function. While aqueous inks often provide the broadest color gamut and most vivid color, most are not waterproof without specialized coating or lamination after printing. Most dye -based inks, while usually the least expensive, are subject to rapid fading when exposed to light or ozone. Pigment -based aqueous inks are typically more costly but provide much better long-term durability and ultraviolet resistance. Inks marketed as " archival quality " are usually pigment-based. Some professional wide format printers use aqueous inks, but

10988-488: The jet as a continuous liquid mass notwithstanding the defective forces which are or may be applied. Furthermore, the color of the ink and the color of the carrier should be such that good optical contrast is formed there between the following printing. The preferred ink is a " hot-melt ink ". That is to say it will assume a solid phase at the temperature of the carrier and liquid phase at some higher temperature. The range of commercially available ink compositions which could meet

11122-407: The late 1990s, monochrome laser printers had become inexpensive enough for home-office use, having displaced other printing technologies, although color inkjet printers (see below) still had advantages in photo quality reproduction. As of 2016 , low-end monochrome laser printers can sell for less than $ 75, and while these printers tend to lack onboard processing and rely on the host computer to generate

11256-476: The later 1950s, heated wax inks became popular with CIJ technologies. In 1971, Johannes F. Gottwald patent US3596285A, Liquid Metal Recorder used molten metal ink with a magnetic flux field to fabricate formed symbols for signage. This may have been the first 3D metal object printed using magnetic core memory as data to produce each symbol. There are many ways to produce a drop-on-demand (DOD) inkjet. Common methods include thermal DOD and piezoelectric DOD to speed up

11390-457: The level of detail and control over the page layout. HP's own LaserJet was driven by a simple page description language , known as Printer Command Language , or PCL. The version for the LaserJet, PCL4, was adapted from earlier inkjet printers with the addition of downloadable bitmapped fonts. It lacked the power and flexibility of PostScript until several upgrades provided some level of parity. It

11524-498: The life of the printer, but can be replaced by the user should they become clogged. Additive manufacturing 3D printheads have very long operating "print times" and failures will occur from internal clogs, orifice damage from bumping obstacles on the print table, calibration failures from overstressed piezoelectric bond life failures and other unexpected causes. Replacement printheads are on spare parts lists for most long use-life 3D printers. The primary cause of inkjet printing problems

11658-402: The life of the printer. The idea is that because the head need not be replaced every time the ink runs out, consumable costs can be made lower and the head itself can be more precise than a cheap disposable one, typically requiring no calibration. On the other hand, if a fixed head is damaged, obtaining a replacement head can become expensive, if removing and replacing the head is even possible. If

11792-474: The loaded paper's length. Once faster-recovery coatings were developed, the drums could touch the paper multiple times in a pass, and therefore be smaller in diameter. A year later, Apple introduced the LaserWriter (also based on the Canon CX engine), but used the newly released PostScript page-description language (up until this point, each manufacturer used its own proprietary page-description language, making

11926-619: The loading of fonts . The Xerox 9700 excelled at printing high-value documents on cut-sheet paper with varying content (e.g. insurance policies). Inspired by the Xerox 9700's commercial success, Japanese camera and optics company Canon developed in 1979 the Canon LBP-10, a low-cost desktop laser printer. Canon then 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 (who rejected

12060-413: The majority in professional use today employ a much wider range of inks, most of which require piezo inkjet heads and extensive maintenance. There are two main design philosophies in inkjet head design: fixed-head and disposable head . Each has its own strengths and weaknesses. The fixed-head philosophy provides an inbuilt print head (often referred to as a gaiter-head ) that is designed to last for

12194-500: The manufacturer to identify the place of purchase, and sometimes the buyer. Digital-rights advocacy groups such as the Electronic Frontier Foundation are concerned about this erosion of the privacy and anonymity of those who print. In particular, the tracking dots were implicated as a tool that directly lead to the arrest and conviction of whistleblower Reality Winner . Inkjet printing Inkjet printing

12328-497: The new printer. Arranging his own funding through a venture capital firm, Brainerd formed Aldus and began development of what would become PageMaker . The venture capital coined the term "desktop publishing" during this time. The LaserWriter was announced at Apple's annual shareholder meeting on January 23, 1985, the same day Aldus announced PageMaker. Shipments began in March 1985 at the retail price of US$ 6,995, significantly more than

12462-567: The offer), Hewlett-Packard (HP), and Apple Computer . In 1981, the first small personal computer designed for office use, the Xerox Star 8010, reached market. The system used a desktop metaphor that was unsurpassed in commercial sales, until the Apple Macintosh . Although it was innovative, the Star workstation was a prohibitively expensive ( US$ 17,000 ) system, affordable only to a fraction of

12596-588: The ones which offered a plug-in PostScript interpreter card, required special parity-type PS/2 RAM modules with a "presence detect" function according to IBM specs. Building on the success of the original LaserWriter, Apple developed many further models. Later LaserWriters offered faster printing, higher resolutions , Ethernet connectivity, and eventually color output in the Color LaserWriter . To compete, many other laser printer manufacturers licensed Adobe PostScript for inclusion into their own models. Eventually

12730-426: The operator to manually clean the print heads and capping mechanism and to replace the wiper blades and other parts used in the automated cleaning processes. The volume of ink used in these printers often leads to "overspray" and therefore buildup of dried ink in many places that automated processes are not capable of cleaning. The ink consumed in the cleaning process needs to be collected to prevent ink from leaking in

12864-552: The original specifications in terms of either tendency to accept a negative charge, to move to the discharged areas of the photoreceptor drum from the developer roll, to fuse appropriately to the paper, or to come off the drum cleanly in each revolution. As with most electronic devices, the cost of laser printers has decreased significantly over the years. In 1984, the HP LaserJet sold for $ 3500, had trouble with even small, low-resolution graphics, and weighed 32 kg (71 lb). By

12998-411: The page description into a bitmap which is stored in the printer's raster memory. Each horizontal strip of dots across the page is known as a raster line or scan line . Laser printing differs from other printing technologies in that each page is always rendered in a single continuous process without any pausing in the middle, while other technologies like inkjet can pause every few lines. To avoid

13132-416: 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 warmup process that a laser printer goes through when power is initially applied to the printer consists mainly of heating the fuser element. The mechanism inside

13266-476: The patent US2566443 invented by Rune Elmqvist dated September 4, 1951. In CIJ technology, a high-pressure pump directs liquid ink from a reservoir through a gunbody and a microscopic nozzle (usually .003 inch diameter), creating a continuous stream of ink droplets via the Plateau-Rayleigh instability . A piezoelectric crystal may be used to create an acoustic wave as it vibrates within the gunbody and causes

13400-402: The photoreceptor drum and deposits it into a waste reservoir. A charge roller then re-establishes a uniform negative charge on the surface of the now-clean drum, readying it to be struck again by the laser. 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

13534-419: 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. LED printers use a linear array of light-emitting diodes to "write" the light on the drum. The toner is based on either wax or plastic, so that when

13668-504: The print heads due to not being the same formulation as the OEM inks, cause leaks, and produce inferior-quality output (e.g., of incorrect color gamut). Consumer Reports has noted that some third-party cartridges may contain less ink than OEM cartridges, and thus yield no cost savings, while Wilhelm Imaging Research claims that with third-party inks the lifetime of prints may be considerably reduced. However, an April 2007 review showed that, in

13802-402: The printer's head cannot be removed, the printer itself will then need to be replaced. Fixed head designs are available in consumer products, but are more likely to be found on industrial high-end printers and large format printers . In the consumer space, fixed-head printers are manufactured primarily by Epson and Canon; however, many more recent Hewlett-Packard models use a fixed head, such as

13936-477: The printer. Some larger professional printers using solvent inks may employ a replaceable plastic receptacle to contain waste ink and solvent, which must be emptied or replaced when full. There is a second type of ink drying that most printers are unable to prevent. For ink to spray from the cartridge, air must enter to displace the removed ink. The air enters via an extremely long, thin labyrinth tube, up to 10 cm (3.9 in) long, wrapping back and forth across

14070-476: The printer. The collection area is called the spittoon , and in Hewlett-Packard printers this is an open plastic tray underneath the cleaning/wiping station. In Epson printers, there is typically a large absorption pad in a pan underneath the paper feed platen. For printers that are several years old, it is common for the dried ink in the spittoon to form a pile that can stack up and touch the printheads, jamming

14204-430: The printhead to be left in an uncapped state. Even when the head is capped, this seal is not perfect, and over a period of several weeks the moisture (or other solvent) can still seep out, causing the ink to dry and harden. Once ink begins to collect and harden, the drop volume can be affected, drop trajectory can change, or the nozzle can completely fail to jet ink. To combat this drying, nearly all inkjet printers include

14338-505: The printhead. Continuous ink system (CISS) inkjet printers connect the printhead either to high-capacity ink tanks or packs, or replenish the built-in cartridges via external tanks connected via tubes, typically a retrofit configuration . Supertank printers –a subset of CISS printers–have high-capacity integrated ink tanks or ink packs, and are manually refilled via ink bottles. When supertank ink systems are paired with disposable printhead technology, replaceable cartridges are used to replace

14472-411: The quality of the inks and paper used. If low-quality paper is used, it can yellow and degrade due to residual acid in the untreated pulp; in the worst case, old prints can literally crumble into small particles when handled. High-quality inkjet prints on acid-free paper can last as long as typewritten or handwritten documents on the same paper. Because the ink used in many low-cost consumer inkjets

14606-421: The receptor material (substrate), or allowed to continue on deflected to a collection gutter for re-use. The more highly charged droplets are deflected to a greater degree. Only a small fraction of the droplets is used to print, the majority being recycled. CIJ is one of the oldest (1951) ink jet technologies in use and is fairly mature. Drop-on-demand was not invented until later. The major advantages of CIJ are

14740-417: The requirement of the invention are not known at the present time. However, satisfactory printing according to the invention has been achieved with a conductive metal alloy as ink. It is extremely hard at room temperature and adheres well to the surface of the carrier. The basic problem with inkjet inks is the conflicting requirements for a coloring agent that will stay on the surface versus rapid bleed through

14874-492: The retail cost of low-end 300-dpi laser printers to decrease to as low as US$ 700 by early 1994 and US$ 600 by early 1995. In September 1997, HP introduced the host-based LaserJet 6L, which could print 600 dpi text at up to six pages per minute for only US$ 400. 1200 dpi printers have been widely available in the home market since 2008. 2400 dpi electrophotographic printing plate makers, essentially laser printers that print on plastic sheets, are also available. In older printers,

15008-438: The same range of tones: neutral, "warm" or "cold". When switching between full-color and monochrome ink sets, it is necessary to flush out the old ink from the print head with a cleaning cartridge . Special software or at least a modified device driver are usually required, to deal with the different color mapping . Some types of industrial inkjet printers are now capable of printing at very high speeds, in wide formats, or for

15142-407: The same time-frame as Apple's LaserWriter, Adobe was licensing the very same version of PostScript to Apple's potential competitors (Apple's PostScript licensing terms were non-exclusive); however, all non-Apple licensees of PostScript generally employed one of Adobe's PostScript "reference models" (Atlas, Redstone, etc.) and even Linotype 's first image setter which featured PostScript employed such

15276-403: The shaft. The pump only engages when the shaft turns backwards, hence the rollers reversing while head cleaning. Due to the built-in head design, the suction pump is also needed to prime the ink channels inside a new printer, and to reprime the channels between ink tank changes. Professional solvent- and UV-curable ink wide-format inkjet printers generally include a "manual clean" mode that allows

15410-415: The standardization on Ethernet for connectivity and the ubiquity of PostScript undermined the unique position of Apple's printers: Macintosh computers functioned equally well with any Postscript printer. After the LaserWriter 8500, Apple discontinued the LaserWriter product line in 1997 when Steve Jobs returned to Apple. In 1988, to address the need for both an affordable printer and a professional printer,

15544-723: The stream of liquid to break into droplets at regular intervals: 64,000 to 165,000 irregular-sized ink droplets per second may be achieved. The ink droplets are subjected to an electrostatic field created by a charging electrode or by a magnetic flux field as they form; the field varies according to the degree of drop deflection desired. This results in a controlled deflection by electrostatic charge on each droplet. Charged droplets may be separated by one or more uncharged "guard droplets" to minimize electrostatic repulsion between neighboring droplets. The droplets pass through another electrostatic or magnetic field and are directed (deflected) by electrostatic deflection plates or flux field to print on

15678-418: The substrate and dry quickly. The ink system requires active solvent regulation to counter solvent evaporation during the time of flight (time between nozzle ejection and gutter recycling), and from the venting process whereby air that is drawn into the gutter along with the unused drops is vented from the reservoir. Viscosity is monitored and a solvent (or solvent blend) is added to counteract solvent loss. In

15812-485: The supporting software complex and expensive). PostScript allowed the use of text, fonts, graphics, images, and color largely independent of the printer's brand or resolution. PageMaker , developed by Aldus for the Macintosh and LaserWriter, was also released in 1985 and the combination became very popular for desktop publishing . Laser printers brought exceptionally fast and high-quality text printing in multiple fonts on

15946-413: The sweep, and the angle of sweep is canted very slightly to compensate for this motion. The stream of rasterized data held in the printer's memory rapidly turns the laser on and off as it sweeps. The laser beam neutralizes (or reverses) the charge on the surface of the drum, leaving a static electric negative image on the drum's surface which will repel the negatively charged toner particles. The areas on

16080-473: The time, Apple planned to release a suite of AppleTalk products as part of the Macintosh Office , with the LaserWriter being only the first component. While competing printers and their associated control languages offered some of the capabilities of PostScript, they were limited in their ability to reproduce free-form layouts (as a desktop publishing application might produce), use outline fonts , or offer

16214-481: The toner cartridges and each of the toner layers are precisely applied to the belt. The combined layers are then applied to the paper in a uniform single step. Color printers usually have a higher cost per page than monochrome printers, even if printing monochrome-only pages. Liquid electrophotography (LEP) is a similar process used in HP Indigo presses that uses electrostatically charged ink instead of toner, and using

16348-530: The unique imaging process. Manufacturers use a similar business model for both low-cost color laser printers and inkjet printers : the printers are sold cheaply while replacement toners and inks are relatively expensive. A color laser printer's average running cost per page is usually slightly less, even though both the laser printer and laser toner cartridge have higher upfront prices, as laser toner cartridges print many more sheets relative to their cost than inkjet cartridges. The print quality of color lasers

16482-416: The upcoming Apple Macintosh computer. Meanwhile, John Warnock had left Xerox to found Adobe Systems to commercialize PostScript and AppleTalk in a laser printer they intended to market. Jobs was aware of Warnock's efforts, and upon his return to California he began convincing Warnock to allow Apple to license PostScript for a new printer that Apple would sell. Negotiations between Apple and Adobe over

16616-545: The use of PostScript began in 1983 and an agreement was reached in December 1983, one month before Macintosh was announced. Jobs eventually arranged for Apple to buy $ 2.5 million in Adobe stock. At about the same time, Jonathan Seybold ( John W. Seybold 's son) introduced Paul Brainerd to Apple, where he learned of Apple's laser printer efforts and saw the potential for a new program using the Mac's GUI to produce PostScript output for

16750-426: The use of the term is no guarantee of quality, and the inks and paper used must be carefully investigated before an archivist can rely on their long-term durability. To increase the durability of inkjet printer prints, more attention is needed for the inkjet ink cartridge. One way to treat ink cartridges on an inkjet printer is to maintain the temperature of the printer itself. Excessive variation in space temperature

16884-425: The very high velocity (≈20 m/s) of the ink droplets, which allows for a relatively long distance between print head and substrate, and the very high drop ejection frequency, allowing for very high speed printing. Another advantage is freedom from nozzle clogging as the jet is always in use, therefore allowing volatile solvents such as ketones and alcohols to be employed, giving the ink the ability to "bite" into

17018-476: The very same LBP-CX form factor, although the external packaging was, for marketing purposes, somewhat different. Since the cost of a LaserWriter was several times that of a dot-matrix impact printer , some means to share the printer with several Macs was desired. LANs were complex and expensive, so Apple developed its own networking scheme, LocalTalk . Based on the AppleTalk protocol stack , LocalTalk connected

17152-480: The workplace. The software can be used to set rules dictating how employees interact with printers, such as setting limits on how many pages can be printed per day, limiting usage of color ink, and flagging jobs that appear to be wasteful. Color laser printers use colored toner (dry ink), typically cyan , magenta , yellow , and black ( CMYK ). While monochrome printers only use one laser scanner assembly, color printers often have two or more, often one for each of

17286-447: The worldwide consumer market, four manufacturers account for the majority of inkjet printer sales: Canon, HP, Epson and Brother . In 1982, Robert Howard came up with the idea to produce a small color printing system that used piezos to spit drops of ink. He formed the company, R.H. (Robert Howard) Research (named Howtek, Inc. in Feb 1984), and developed the revolutionary technology that led to

17420-488: Was also one of Apple's most expensive offerings. For implementation purposes, the LaserWriter employed a small number of medium-scale-integration Monolithic Memories PALs , and no custom LSI , whereas the LaserJet employed a large number of small-scale-integration Texas Instruments 74-Series gates, and one custom LSI. The LaserWriter was, thereby, in the same form factor (for its RIP ), able to provide much greater function, and, indeed, much greater performance, all within

17554-443: Was of its own design, and was implemented using few ICs, including PALs for most combinatorial logic; with the subsystem timing DRAM refreshing, and rasterization functions being implemented in very few medium-scale-integration PALs. Apple's competitors (i.e., QMS , NEC , and others) generally used a variation of one of Adobe's RIPs with their large quantity of small-scale-integration (i.e., Texas Instruments ' 7400 series) ICs. In

17688-424: Was only discovered in the 1920s. The continuous inkjet (CIJ) method is used commercially for marking and coding of products and packages. In 1867, Lord Kelvin patented the syphon recorder , which recorded telegraph signals as a continuous trace on paper using an ink jet nozzle deflected by a magnetic coil. The first commercial devices (medical strip chart recorders ) were introduced in 1951 by Siemens . using

17822-400: Was some time before similar products became available on other platforms, by which time the Mac had ridden the desktop publishing market to success. The LaserWriter used the same Canon CX printing engine as the HP LaserJet, and as a consequence early LaserWriters and LaserJets shared the same toner cartridges and paper trays. PostScript is a complete programming language that has to be run in

17956-450: Was used for high-volume printing on continuous stationery , and achieved speeds of 215 pages per minute (ppm), at a resolution of 240 dots per inch (dpi). Over 8,000 of these printers were sold. Soon after, in 1977, the Xerox 9700 was brought to market. Unlike the IBM 3800, the Xerox 9700 was not targeted to replace any particular existing printers; however, it did have limited support for

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