Dot matrix printer

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An Epson MX-80, a classic model that remained in use for many years. IBM sold it as their IBM 5152. Epson MX-80.jpg
An Epson MX-80, a classic model that remained in use for many years. IBM sold it as their IBM 5152.
A rail ticket printed with dot matrix printer Indian railway suburban rail ticket.jpg
A rail ticket printed with dot matrix printer

A dot matrix printer is an impact printer that prints using a fixed number of pins or wires. [2] [3] Typically the pins or wires are arranged in one or several vertical columns. The pins strike an ink-coated ribbon and force contact between the ribbon and the paper, so that each pin makes a small dot on the paper. The combination of these dots forms a dot matrix image. They were also known as serial dot matrix printers. [4]

Contents

While inkjet and laser printers technically exhibit dot matrix printing, they work differently than impact "dot matrix printers" and can deposit ink or toner at higher dot resolutions more quickly, with less inherent noise. The impact printer has the ability to make copies using multi-part forms, unlike an inkjet or laser printer. [5]

History

In the 1970s and 1980s, dot matrix impact printers were generally considered the best combination of cost and versatility, and until the 1990s were by far the most common form of printer used with personal and home computers. [6] [7]

The first impact dot matrix printer was the Centronics 101. [8] [9] Introduced in 1970, [10] it led to the design of the parallel electrical interface that was to become standard on most printers until it was displaced well over two decades later by the Universal Serial Bus (USB).

Digital Equipment Corporation (DEC) was another major vendor, albeit with a focus on use with their PDP minicomputer line. [11] Their LA30 30 character/second (CPS) dot matrix printer, the first of many, was introduced in 1970.

By the dawn of the 1990s, inkjet printers became more common as PC printers. [12] [13]

DEC's dot matrix printers

Unlike the LA30's 80-column, uppercase-only 5x7 dot matrix, DEC's product line grew. New models included:

LA30

The DECwriter LA30 was a 30 character per second dot matrix printing terminal introduced in 1970 by Digital Equipment Corporation (DEC) of Maynard, Massachusetts [15]

It printed 80 columns of uppercase-only 7×5 dot matrix characters across a unique-sized paper. The printhead was driven by a stepper motor and the paper was advanced by a noisy solenoid ratchet drive. The LA30 was available with both a parallel interface (LA30-P) and a serial interface (LA30-S); however, the serial LA30 required the use of fill characters during the carriage-return. In 1972, a receive-only variation named LA30A became available.

LA36

The LA30 was followed in 1974 by the LA36, [16] which achieved far greater commercial success, [17] becoming for a time the standard dot matrix computer terminal. The LA36 used the same print head as the LA30 but could print on forms of any width up to 132 columns of mixed-case output on standard green bar fanfold paper. [17] The carriage was moved by a much-more-capable servo drive using a DC electric motor and an optical encoder / tachometer. The paper was moved by a stepper motor. The LA36 was only available with a serial interface but unlike the earlier LA30, no fill characters were required. This was possible because, while the printer never communicated at faster than 30 characters per second, the mechanism was actually capable of printing at 60 characters per second. During the carriage return period, characters were buffered for subsequent printing at full speed during a catch-up period. The two-tone buzz produced by 60-character-per-second catch-up printing followed by 30-character-per-second ordinary printing was a distinctive feature of the LA36, quickly copied by many other manufacturers well into the 1990s. Most efficient dot matrix printers used this buffering technique.

Digital technology later broadened the basic LA36 line into a wide variety of dot matrix printers.

LA50

The DEC LA50 was designed to be a "compact, dot matrix" [11] printer. When in graphic mode (as opposed to text mode), the printhead can generate graphic images. When in (bitmap) graphics mode, the LA50 can receive and print Sixel [18] graphics format.

The Wikipedia logo, converted to Sixel format Sixel Wikipedia logo.png
The Wikipedia logo, converted to Sixel format

Centronics 101

The Centronics 101 [19] (introduced 1970) was highly innovative and affordable at its inception. Some selected specifications:

IBM 5103

The IBM 5103 [20] was the only IBM printer that could be attached to the IBM 5100, an early day portable computer. Printing was 8 DPI, 10 pitch, 6 LPI, and capable of printing bidirectionally from a 128 character set. Two models were offered: [21] 80 and 120 characters per second. [22]

Low-cost dot-matrix printers

In the mid-1980s, dot-matrix printers were dropping in price, [3] [23] and, being "faster and more versatile than daisywheel printers" (including becoming even more flexible in what they can do because of 24-pin print heads, versus the earlier 9-pin models) they've continued to sell. [24]

Increased pincount of the printhead from 7, 8, 9 or 12 pins to 18, 24, 27, 36 permitted superior print-quality, which was necessary for success in Asian markets to print legible CJKV characters. [25] Epson's 24-pin LQ-series rose to become the new de facto standard, at 24/180 inch (per pass - 7.5 lpi). Not only could a 24-pin printer lay down a denser dot-pattern in a single-pass, it could simultaneously cover a larger area and print more quickly (largely due to the 24-pin's ability to print NLQ with a single pass).

Although the text-quality of a 24-pin was still visibly inferior to a true letter-quality printer such as a daisy wheel or laser-printer, as manufacturing costs declined, 24-pin printers gradually replaced 9-pin printers.

Draft mode

To obtain the maximum output speed, albeit at a lower quality, each character and line is only printed once. This is called "draft mode".

Near Letter Quality (NLQ)

Near Letter Quality modeinformally specified as almost good enough to be used in a business letter [26] endowed dot-matrix printers with a simulated typewriter-like quality. By using multiple passes of the carriage, and higher dot density, the printer could increase the effective resolution. In 1985, The New York Times described the use of "near letter-quality, or N.L.Q." and "near letter quality" as "just a neat little bit of hype" [3] but acknowledged that they "really show their stuff in the area of fonts, print enhancements and graphics."

PC usage

In 1985, PC Magazine wrote "for the average personal computer user dot matrix remains the most workable choice". [1] At the time, IBM sold Epson's MX-80 as their IBM 5152. [27]

Another technology, inkjet printing, which uses the razor and blades business model (give away the razor handle, make money on the razor blade) [28] has reduced the value of the low cost for the printer: "a price per milliliter on par with liquid gold" for the ink/toner. [29]

Personal computers

In June 1978, the Epson TX-80/TP-80, [30] an 8-pin dot-matrix printer mainly used for the Commodore PET computer, was released. This and its successor, the 9-pin MX-80/MP-80 (introduced in 1979/1980), [31] sparked the popularity of impact printers in the personal computer market. [32] The MX-80 combined affordability with good-quality text output (for its time). Early impact printers (including the MX) were notoriously loud during operation, a result of the hammer-like mechanism in the print head. The MX-80 even inspired the name of a noise rock band. [33] The MX-80's low dot density (60 dpi horizontal, 72 dpi vertical) produced printouts of a distinctive "computerized" quality. When compared to the crisp typewriter quality of a daisy-wheel printer, the dot-matrix printer's legibility appeared especially bad. In office applications, output quality was a serious issue, as the dot-matrix text's readability would rapidly degrade with each photocopy generation.

PC Software

Initially, third-party printer enhancement software offered a quick fix to the quality issue. General strategies were:

  • doublestrike (print each line twice), and
  • double-density mode (slow the print head to allow denser and more precise dot placement).

Some newer dot-matrix impact printers could reproduce bitmap images via "dot-addressable" capability. In 1981, Epson offered a retrofit EPROM kit called Graftrax to add this to many early MX series printers. Banners and signs produced with software that used this ability, such as Broderbund's Print Shop, became ubiquitous in offices and schools throughout the 1980s.

As carriage speed increased and dot density increased (from 60 dpi up to 240 dpi), with some adding color printing, additional typefaces allowed the user to vary the text appearance of printouts. Proportional-spaced fonts allowed the printer to imitate the non-uniform character widths of a typesetter, and also darker printouts. 'User-downloadable fonts' gave until the printer was powered off or soft-reset. The user could embed up to 2 NLQ custom typefaces in addition to the printer's built-in (ROM) typefaces.

Upper: Inmac ink ribbon cartridge with black ink for Dot matrix printer. Lower: Inked and folded, the ribbon is pulled into the cartridge by the roller mechanism to the left Ink cartridgee and inside zoom.jpg
Upper: Inmac ink ribbon cartridge with black ink for Dot matrix printer. Lower: Inked and folded, the ribbon is pulled into the cartridge by the roller mechanism to the left

Contemporary use

The desktop impact printer was gradually replaced by the inkjet printer. When Hewlett-Packard's patents expired on steam-propelled photolithographically produced ink-jet heads,[ when? ] the inkjet mechanism became available to the printer industry. For applications that did not require impact (e.g. carbon-copy printing), the inkjet was superior in nearly all respects: comparatively quiet operation, faster print speed, and output quality almost as good as a laser printer. By 1995, inkjet technology had surpassed dot matrix impact technology in the mainstream market and relegated dot matrix to niche applications. [34]

As of 2021, dot matrix impact technology remains in use in devices and applications such as:

Thermal printing is gradually supplanting them in some of these applications, but full-size dot-matrix impact printers are still used to print multi-part stationery. For example, dot matrix impact printers are still used at bank tellers and auto repair shops, and other applications where use of tractor feed paper is desirable such as data logging and aviation. Most of these printers now come with USB interfaces as a standard feature, to facilitate connections to modern computers without legacy ports.

Vendors

Some companies, such as Printek, DASCOM, WeP Peripherals, Epson, Okidata, Olivetti, Compuprint, Lexmark, and TallyGenicom still produce serial printers. Printronix is now the only manufacturer of line printers. Today, a new dot matrix printer actually costs more than most inkjet printers and some entry-level laser printers. Despite this initial price difference, the printing costs for inkjet and laser printers are a great deal higher than for dot matrix printers, and the inkjet/laser printer manufacturers effectively use their monopoly over arbitrarily priced printer cartridges to subsidize the initial cost of the printer itself. Dot matrix ribbons are a commodity and are not monopolized by the printer manufacturers themselves.

Related Research Articles

Printer (computing) Computer peripheral that prints text or graphics

In computing, a printer is a peripheral machine which makes a persistent representation of graphics or text, usually on paper. While most output is human-readable, bar code printers are an example of an expanded use for printers. Different types of printers include 3D printers, inkjet printers, laser printers, and thermal printers.

Laser printing Electrostatic digital printing process

Laser printing is an electrostatic digital printing process. It produces high-quality text and graphics by repeatedly passing a laser beam back and forth over a negatively-charged cylinder called a "drum" to define a differentially-charged image. The drum then selectively collects electrically-charged powdered ink (toner), and transfers the image to paper, which is then heated to permanently fuse the text, imagery, or both, to the paper. As with digital photocopiers, laser printers employ a xerographic printing process. Laser printing differs from traditional xerography as implemented in analog photocopiers in that in the latter, the image is formed by reflecting light off an existing document onto the exposed drum.

Dot matrix printing

Dot matrix printing, sometimes called impact matrix printing, is a computer printing process in which ink is applied to a surface using a relatively low-resolution dot matrix for layout. Dot matrix printers typically use a print head that moves back and forth or in an up-and-down motion on the page and prints by impact, striking an ink-soaked cloth ribbon against the paper, much like the print mechanism on a typewriter or line printer. However, a dot matrix printer is able to print arbitrary patterns and not just specific characters.

A page printer is a computer printer which processes and prints a whole page at a time, as opposed to printers which print one line or character at a time such as line printers and dot-matrix printers. Page printers are often all incorrectly termed “laser printers”—although virtually all laser printers are page printers, other page printing technologies also exist

Inkjet printing Type of computer printing

Inkjet printing 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%.

Dot matrix

A dot matrix is a 2-dimensional patterned array, used to represent characters, symbols and images. Most types of modern technology use dot matrices for display of information, including mobile phones, televisions, and printers. The system is also used in textiles with sewing, knitting and weaving.

Daisy wheel printing Impact printing technology

Daisy wheel printing is an impact printing technology invented in 1970 by Andrew Gabor at Diablo Data Systems. It uses interchangeable pre-formed type elements, each with typically 96 glyphs, to generate high-quality output comparable to premium typewriters such as the IBM Selectric, but two to three times faster. Daisy wheel printing was used in electronic typewriters, word processors and computers from 1972. The daisy wheel is so named because of its resemblance to the daisy flower.

Parallel port Computer interface

In computing, a parallel port is a type of interface found on early computers for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once, as opposed to serial communication, in which bits are sent one at a time. To do this, parallel ports require multiple data lines in their cables and port connectors and tend to be larger than contemporary serial ports, which only require one data line.

Centronics Data Computer Corporation was an American manufacturer of computer printers, now remembered primarily for the parallel interface that bears its name, the Centronics connector.

ImageWriter

The ImageWriter is a product line of dot matrix printers formerly manufactured by Apple Computer, Inc., and designed then to be compatible with their entire line of computers. There were three different models introduced over time, which were popular mostly among Apple II and Macintosh owners.

Dots per inch Measure of dot density

Dots per inch is a measure of spatial printing, video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm). Similarly, the more newly introduced dots per centimetre refers to the number of individual dots that can be placed within a line of 1 centimetre (0.394 in).

Thermal-transfer printing

Thermal-transfer printing is a digital printing method in which material is applied to paper by melting a coating of ribbon so that it stays glued to the material on which the print is applied. It contrasts with direct thermal printing, where no ribbon is present in the process.

HP LaserJet

LaserJet as a brand name identifies the line of laser printers marketed by the American computer company Hewlett-Packard (HP). The HP LaserJet was the world's first desktop laser printer. Canon supplies both mechanisms and cartridges for all HP's laser printers.

IEEE 1284 Standard for parallel peripheral interfaces, known as the Centronics port

IEEE 1284 is a standard that defines bi-directional parallel communications between computers and other devices. It was originally developed in the 1970s by Centronics, and was widely known as the Centronics port, both before and after its IEEE standardization.

Epson Japanese multinational electronics company

Seiko Epson Corporation, or simply known as Epson, is a Japanese multinational electronics company and one of the world's largest manufacturers of computer printers and information- and imaging-related equipment. Headquartered in Suwa, Nagano, Japan, the company has numerous subsidiaries worldwide and manufactures inkjet, dot matrix, thermal and laser printers for consumer, business and industrial use, scanners, laptop and desktop computers, video projectors, watches, point of sale systems, robots and industrial automation equipment, semiconductor devices, crystal oscillators, sensing systems and other associated electronic components. The company has developed as one of manufacturing and research & development companies of the Seiko Group, a name traditionally known for manufacturing Seiko timepieces since its founding. Seiko Epson was one of the major companies in the Seiko Group, but does not belong to the Seiko Holdings Group.

A letter-quality printer was a form of computer impact printer that was able to print with the quality typically expected from a business typewriter such as an IBM Selectric.

ESC/P, short for Epson Standard Code for Printers and sometimes styled Escape/P, is a printer control language developed by Epson to control computer printers. It was mainly used in dot matrix printers and some inkjet printers, and is still widely used in many receipt thermal printers. During the era of dot matrix printers, it was also used by other manufacturers, sometimes in modified form. At the time, it was a popular mechanism to add formatting to printed text, and was widely supported in software.

DECwriter

The DECwriter series was a family of computer terminals from Digital Equipment Corporation (DEC). They were typically used in a fashion similar to a teletype, with a computer output being printed to paper and the user inputting information on the keyboard. In contrast to teletypes, the DECwriters were based on dot matrix printer technology, one of the first examples of such a system to be introduced. Versions lacking a keyboard were also available for use as computer printers, which eventually became the only models as smart terminals became the main way to interact with mainframes and minicomputers in the 1980s.

Near letter-quality (NLQ) printing is a process where dot matrix printers produce high-quality text by using multiple passes to produce higher dot density. The tradeoff for the improved print quality is reduced printing speed. Software can also be used to produce this effect. The term was coined in the 1980s to distinguish NLQ printing from true letter-quality printing, as produced by a printer based on traditional typewriter technology such as a daisy wheel, or by a laser printer.

References

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