9-pin dot matrix

Dot matrix printing is the process of computer printing from a collection of dot matrix data to a device, which can be one of:

Dot matrix (impact) 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.

These printers can print on multi-part (carbon paper) forms since they print using mechanical pressure.

Sometimes called impact matrix printing or dot matrix printing, this 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.

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.

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.

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Wikipedia