Dot matrix printing

Dot matrix printing or impact matrix printing is a type of computer printing which uses 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. However, unlike a typewriter or daisy wheel printer, letters are drawn out of a dot matrix, and thus, varied fonts and arbitrary graphics can be produced.

Design

Each dot is produced by a tiny metal rod, also called a "wire" or "pin", which is driven forward by the power of a tiny electromagnet or solenoid, either directly or through small levers (pawls). Facing the ribbon and the paper is a small guide plate named ribbon mask holder or protector, sometimes also called butterfly for its typical shape. It is pierced with holes to serve as guides for the pins. This plate may be made of hard plastic or an artificial jewel such as sapphire or ruby.

The portion of the printer containing the pins is called the print head. When running the printer, it generally prints one line of text at a time. There are two approaches to achieve this:

Dot matrix

A dot matrix is a 2-dimensional patterned array, used to represent characters, symbols and images. Every type of modern technology uses dot matrices for display of information, including cell phones, televisions, and printers. They are also used in textiles with sewing, knitting, and weaving.

An alternate form of information display using lines and curves is known as a vector display, was used with early computing devices such as air traffic control radar displays and pen-based plotters but is no longer used. Electronic vector displays were typically monochrome only, and either don't fill in the interiors of closed vector shapes, or shape-filling is slow, time-consuming, and often non-uniform, as on pen-based plotters.

In printers, the dots are usually the darkened areas of the paper. In displays, the dots may light up, as in an LED, CRT, or plasma display, or darken, as in an LCD.

Usage in printers

As an impact printer, the term mainly refers to low-resolution impact printers, with a column of 8, 9 or 24 "pins" hitting an ink-impregnated fabric ribbon, like a typewriter ribbon, onto the paper. It was originally contrasted with both daisy wheel printers and line printers that used fixed-shape embossed metal or plastic stamps to mark paper.

Bohemian Rhapsody

"Bohemian Rhapsody" is a song by the British rock band Queen. It was written by Freddie Mercury for the band's 1975 studio album A Night at the Opera. It is a six-minute suite, consisting of several sections without a chorus: an intro, a ballad segment, an operatic passage, a hard rock part and a reflective coda. The song is a more accessible take on the 1970s progressive rock genre. It was the most expensive single ever made at the time of its release.

When it was released as a single, "Bohemian Rhapsody" became a commercial success, staying at the top of the UK Singles Chart for nine weeks and selling more than a million copies by the end of January 1976. It reached number one again in 1991 for another five weeks when the same version was re-released, eventually becoming the UK's third best-selling single of all time. It topped the charts in several other markets as well, including Canada, Australia, New Zealand, Ireland and The Netherlands, later becoming one of the best-selling singles of all time. In the United States the song originally peaked at number nine in 1976. It returned to the chart at number two in 1992 following its appearance in the film Wayne's World, which revived its American popularity.