Editing Printer (computing) (section)

=====Dot-matrix printers=====
{{main|Dot matrix printer}}

[[File:Dot matrix example text.png|thumb|right|Sample output from  9-pin dot matrix printer (one character expanded to show detail)]]
The term [[dot matrix printer]] is used for impact printers that use a matrix of small [[pin]]s to transfer ink to the page.<ref>{{cite book
 |author1=David W. Beskeen |author2=Carol Cram |author3=Jennifer Duffy |author4=Lisa Friedrichsen |author5=Elizabeth Eisner Reding
 |title=Microsoft Office 2007 illustrated: Introductory
 |url=https://archive.org/details/microsoftofficew00jenn_1|url-access=registration|date=2008|publisher=Thomson Course Technology|location=Boston, Mass.|isbn=978-1418860479
 |edition=Windows XP}}</ref> The advantage of dot matrix over other impact printers is that they can produce [[graphic design|graphical]] images in addition to text; however the text is generally of poorer quality than impact printers that use letterforms (''type'').

Dot-matrix printers can be broadly divided into two major classes:
* Ballistic wire printers
* [[Stored energy printer]]s

Dot matrix printers can either be [[character (computing)|character]]-based or line-based (that is, a single horizontal series of pixels across the page), referring to the configuration of the print head.

In the 1970s and '80s, dot matrix printers were one of the more common types of printers used for general use, such as for home and small office use. Such printers normally had either 9 or 24 pins on the print head (early 7 pin printers also existed, which did not print [[descender]]s). There was a period during the early home computer era when a range of printers were manufactured under many brands such as the [[Commodore International|Commodore]] VIC-1525 using the [[Seikosha]] '''Uni-Hammer''' system.  This used a single solenoid with an oblique striker that would be actuated 7 times for each column of 7 vertical pixels while the head was moving at a constant speed. The angle of the striker would align the dots vertically even though the head had moved one dot spacing in the time.  The vertical dot position was controlled by a synchronized longitudinally ribbed platen behind the paper that rotated rapidly with a rib moving vertically seven dot spacings in the time it took to print one pixel column.<ref>{{cite web|title=VIC-1525 Graphics Printer User Manual|url=http://www.classiccmp.org/cini/pdf/Commodore/VIC-1525%20Printer%20User%27s%20Manual.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.classiccmp.org/cini/pdf/Commodore/VIC-1525%20Printer%20User%27s%20Manual.pdf |archive-date=2022-10-09 |url-status=live|publisher=Commodore Computer|access-date=22 February 2015}}</ref> 24-pin print heads were able to print at a higher quality and started to offer additional type styles and were marketed as [[Dot matrix printing#Near Letter Quality .28NLQ.29|Near Letter Quality]] by some vendors. Once the price of inkjet printers dropped to the point where they were competitive with dot matrix printers, dot matrix printers began to fall out of favour for general use.

Some dot matrix printers, such as the NEC P6300, can be upgraded to print in color. This is achieved through the use of a four-color ribbon mounted on a mechanism (provided in an upgrade kit that replaces the standard black ribbon mechanism after installation) that raises and lowers the ribbons as needed. Color graphics are generally printed in four passes at standard resolution, thus slowing down printing considerably. As a result, color graphics can take up to four times longer to print than standard monochrome graphics, or up to 8-16 times as long at high resolution mode.

Dot matrix printers are still commonly used in low-cost, low-quality applications such as [[cash register]]s, or in demanding, very high volume applications like [[invoice]] printing. Impact printing, unlike laser printing, allows the pressure of the print head to be applied to a stack of two or more forms to print [[Multipart stationery|multi-part documents]] such as sales invoices and [[credit card]] receipts using [[continuous stationery]] with [[carbonless copy paper]]. It also has security advantages as ink impressed into a paper matrix by force is harder to erase invisibly. Dot-matrix printers were being superseded even as receipt printers after the end of the twentieth century.