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Dot matrix printing

technology Maturity 9-11 Next article →

Dot matrix printing, also known as impact matrix printing, is a computer printing process. It uses a low-resolution dot matrix to create layouts on a surface. This method is classified as an impact printing technology. Unlike inkjet or laser printers, it relies on physical contact to transfer ink.

Dot matrix example text
Dot matrix example text

This capability makes it unique in the world of computer hardware. It remains useful for specific tasks that require physical pressure.

The mechanism of a dot matrix printer is a mechanical process. The print head contains a fixed number of small metal rods called pins or wires.

Tally Genicom T2240 print head pins
Tally Genicom T2240 print head pins

These pins are driven forward by tiny electromagnets known as solenoids. Each solenoid can act on a pin, either directly or through small levers called pawls.

Tally Genicom T2240 print head assembly - cross section
Tally Genicom T2240 print head assembly - cross section

As a pin moves, it strikes an ink-soaked cloth ribbon against the paper. The print head typically moves in a back-and-forth or up-and-down motion. This movement allows the pins to create a pattern of dots. These dots combine to form characters or arbitrary graphics.

There are several distinct types of dot matrix printers. Serial impact dot matrix printers (SIDM) use a horizontally moving print head. This head usually features a vertical column of pins.

9 nadel druckkopf-star nl10--hinnerk ruemenapf vs01-p50
9 nadel druckkopf-star nl10--hinnerk ruemenapf vs01-p50

Some designs use up to four slightly displaced columns to increase dot density. This technique is called interleaving. Another type is the line matrix printer. These use a fixed print head that is almost as wide as the paper path. A line matrix printer uses thousands of pins to print a whole line at once. There is also a variation called the cross hammer dot printer. This uses a spinning, fluted cylinder and a hammer to mark dots.

The history of this technology spans many decades. In 1925, Rudolf Hell invented the Hellschreiber, a facsimile-like teletypewriter. Fritz Karl Preikschat later developed the PKT printer in Germany between 1954 and 1956. In 1968, the Japanese manufacturer OKI introduced the Wiredot. This was the first serial impact dot matrix printer.

Epson MX-80
Epson MX-80

Digital Equipment Corporation (DEC) entered the market in 1970 with the LA30 printer. By the mid-1980s, dot matrix printers were outselling daisywheel printers. They were favored for their high speed and versatility. The Apple ImageWriter became a popular consumer model during the 1980s.

Specific technical details define the quality and speed of these machines. The resolution depends on the number of pins in the print head. Common configurations include 9-pin and 24-pin models.

Tally Genicom T2240 print head assembly - cross section
Tally Genicom T2240 print head assembly - cross section

A 24-pin printer can overlap adjacent dots to produce near letter-quality (NLQ) output. This improves visual quality but often reduces speed. Speed is measured in characters per second (CPS). The DEC LA30 printed at 30 CPS. However, line matrix printers are much faster. They can achieve throughputs of up to 800 pages per hour. They can also print more than 1000 CPS.

Dot matrix printers offer unique advantages over non-impact methods. Because they use mechanical pressure, they can print on multi-part forms. This allows for the simultaneous creation of multiple copies. These copies can even be on different colors of paper.

Indian railway suburban rail ticket
Indian railway suburban rail ticket

They also support the use of continuous, fanfolded paper with tractor holes.

This makes them ideal for long documents like receipts. Despite being noisier than laser printers, they have very low printing costs per page.

This technology connects to broader developments in computing and communication. The design of Centronics printers led to a parallel electrical interface. This interface became a standard for most printers until the late 1990s. This was when the Universal Serial Bus (USB) began to replace it. Dot matrix printing also shows the evolution of digital character representation. While modern printers use higher resolutions, the concept of using a bitmap for layout remains a shared foundation.

Epson dot matrix printer
Epson dot matrix printer
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🖼️ Images & Media (13)
File:Tally 5040 Passbook dot matrix printer.jpg
Tally 5040 Passbook dot matrix printer.jpg
File:"Delivery", printed in a bold, large font on a dot matrix printer.jpg
"Delivery", printed in a bold, large font...
File:Indian railway suburban rail ticket.jpg
Indian railway suburban rail ticket.jpg
File:Epson MX-80.jpg
Epson MX-80.jpg
File:Dot matrix example text.png
Dot matrix example text.png
File:Printer dot matrix EPSON VP-500.jpg
Printer dot matrix EPSON VP-500.jpg
File:Tally Genicom T2240 print head assembly - cross section.jpg
Tally Genicom T2240 print head assembly -...
File:Epson dot matrix printer.jpg
Epson dot matrix printer.jpg
File:Epson Wide Carriage 9-pin printer - with legal paper 8.5x14.jpg
Epson Wide Carriage 9-pin printer - with...
File:Tally Genicom T2240 print head pins.jpg
Tally Genicom T2240 print head pins.jpg
File:9 nadel druckkopf-star nl10--hinnerk ruemenapf vs01-p50.jpg
9 nadel druckkopf-star nl10--hinnerk...
File:IBM 5103 printer in Tekniska museet (1).jpg
IBM 5103 printer in Tekniska museet (1).jpg

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