page_title: Dot matrix printing
section_title: Design
hierarchical_section_title: Dot matrix printing / Design
caption_attribution_description: Close-up of text from a dot-matrix printer. This is representative of the most basic output from a 9-pin printer (or one in draft mode), without NLQ. Note the enlargement of single letter for detail. Scale: This image represents an area of approximately 4.5 x 1.5 cm.
context_page_description: 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.
  The perceived quality of dot matrix printers depends on the vertical and horizontal resolution and the ability of the printer to overlap adjacent dots. 9-pin and 24-pin are common; this specifies the number of pins in a specific vertically aligned space. With 24-pin printers, the horizontal movement can slightly overlap dots, producing visually superior output, usually at the cost of speed.
  Dot matrix printing is typically distinguished from non-impact methods, such as inkjet, thermal, or laser printing, though they too may use a bitmap to represent the printed work.
context_section_description: Dot matrix printing 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.
  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. The plate may be made of hard plastic or an artificial jewel such as sapphire or ruby.
  The portion of the printer that contains the pin is called the print head. When running the printer, it generally prints one line of text at a time. The printer head is attached to a metal bar that ensures correct alignment, but horizontal positioning is controlled by a band that attaches to sprockets on two wheels at each side which is then driven with an electric motor. This band may be made of stainless steel, phosphor bronze or beryllium copper alloys, nylon or various synthetic materials with a twisted nylon core to prevent stretching.  Actual position can be found out either by dead count using a stepper motor, rotary encoder attached to one wheel or a transparent plastic band with markings that is read by an optical sensor on the printer head (common on inkjets).
  Because the printing involves mechanical pressure, dot matrix printers can create carbon copies and carbonless copies.
  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.
  Dot matrix printers have one of the lowest printing costs per page.
  They are able to use fanfold continuous paper with tractor holes.
  Dot matrix printers create noise when the pins or typeface strike the ribbon to the paper, and sound-damping enclosures may have to be used in quiet environments.
  They can only print lower-resolution graphics, with limited color performance, limited quality, and lower speeds compared to non-impact printers.
caption: Typical output from a dot matrix printer operating in draft mode. This entire image represents an area of printer output approximately 4.5 cm × 1.5 cm (1.77 in × 0.59 in) in size
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