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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: The common ''serial dot matrix printers'' use a horizontally moving print head. The print head can be thought of featuring a single vertical column of seven or more pins approximately the height of a character box. In reality, the pins are arranged in up to four vertically or/and horizontally slightly displaced columns in order to increase the dot density and print speed through interleaving without causing the pins to jam. Thereby, up to 48 pins can be used to form the characters of a line while the print head moves horizontally. In a considerably different configuration, so called ''line dot matrix printers'' use a fixed print head almost as wide as the paper path utilizing a horizontal line of thousands of pins for printing. Sometimes two horizontally slightly displaced rows are used to improve the effective dot density through interleaving. While still line-oriented, these printers for the professional heavy-duty market effectively print a whole line at once while the paper moves forward below the print head. The printing speed of ''serial dot matrix printers'' with moving heads varies from 30 to 550 cps. In contrast to this, ''line matrix printers'' are capable of printing much more than 1000 cps, resulting in a throughput of up to 800 pages/hour. Because the printing involves mechanical pressure, both of these types of printers can create carbon copies and carbonless copies. These machines can be highly durable. When they do wear out, it is generally due to ink invading the guide plate of the print head, causing grit to adhere to it; this grit slowly causes the channels in the guide plate to wear from circles into ovals or slots, providing less and less accurate guidance to the printing wires. Eventually, even with tungsten blocks and titanium pawls, the printing becomes too unclear to read, a common problem when users failed to maintain the printer with regular cleaning as outlined in most user manuals. A variation on the dot matrix printer was the ''cross hammer dot printer'', patented by Seikosha in 1982.〔(''Patent US4462705 Cross hammer dot printer'' ), Google Patents, accessed 2013-10-01〕 The smooth cylindrical roller of a conventional printer was replaced by a spinning, fluted cylinder. The print head was a simple hammer, with a vertical projecting edge, operated by an electromagnet. Where the vertical edge of the hammer intersected the horizontal flute of the cylinder, compressing the paper and ribbon between them, a single dot was marked on the paper. Characters were built up of multiple dots. Although nearly all inkjet, thermal, and laser printers also print closely spaced dots rather than continuous lines or characters, it is not customary to call them dot matrix printers. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Dot matrix printing」の詳細全文を読む スポンサード リンク
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