What are printers?

What do printers do?

A printer is a device that receives text and graphic output from a computer and prints the data on paper, typically on sheets of paper that are standard size, 8.5" by 11". The size, speed, sophistication, and price of printers varies. For more frequent printing or color printing with high resolution, more expensive printers are typically employed.

Impact and non-impact personal computer printers can be distinguished from one another. Early impact printers used a key to make an inked impression on the paper for each printed character, operating somewhat like an automatic typewriter. A common low-cost choice was the dot matrix printer, an impact printer that prints one line at a time on the paper.

The inkjet and laser printers are the most popular non-impact printing devices. While the laser printer employs a laser beam reflected from a mirror to attract ink (referred to as toner) to specific paper locations as a sheet rolls over a drum, the inkjet printer sprays ink from an ink cartridge at very close range to the paper as it rolls by.

Different types of printers

There are many different printer manufacturers available today, including Canon, Epson, Hewlett-Packard, Xerox and Lexmark, among many others. There are also several types of printers to choose from, which we'll explore below.

• Inkjet printers recreate a digital image by spraying ink onto paper. These are the most common type of personal printer.
• Laser printers are used to create high-quality prints by passing a laser beam at a high speed over a negatively charged drum to define an image. Color laser printers are more often found in professional settings.
• 3D printers are a relatively new printer technology. 3D printing creates a physical object from a digital file. It works by adding layer upon layer of material until the print job is complete and the object is whole.
• Thermal printers produce an image on paper by passing paper with a thermochromic coating over a print head comprised of electrically heated elements and produces an image in the area where the heated coating turns black. A dye-sublimation printer is a form of thermal printing technology that uses heat to transfer dye onto materials.
• All-in-one printers are multifunction devices that combine printing with other technologies such as a copier, scanner and/or fax machine.
• LED printers are similar to laser printers but use a light-emitting diode array in the print head instead of a laser.
• Photo printers are similar to inkjet printers but are designed specifically to print high-quality photos, which require a lot of ink and special paper to ensure the ink doesn't smear.

Older printer types

There are a few first-generation printer types that are outdated and rarely used today:

• Dot matrix printer: Dot matrix printing is an older impact printer technology for text documents that strikes the paper one line at a time. Dot matrix printers offer very basic print quality.
• Line printer: A line printer prints a single line of text at a time. While an older form of printing, line printers are still in use today.

Features to look for in a printer

The four printer qualities of most interest to users are:

• Color: Most modern printers offer color printing. However, they can also be set to print in black and white. Color printers are more expensive to operate since they use two ink cartridges -- one color and one black ink -- or toners that need to be replaced after a certain number of pages are printed. Printing ink cartridges or toner cartridges are comprised of black, cyan, magenta and yellow ink. The ink can be mixed together, or it may come in separate monochrome solid ink printer cartridges, depending on the type of printer.
• Resolution: Printer resolution -- the sharpness of text and images on paper -- is usually measured in dots per inch (dpi). Most inexpensive printers provide sufficient resolution for most purposes at 600 dpi.
• Speed: If a user does a lot of printing, printing speed is an important feature. Inexpensive printers print only about 3 to 6 sheets per minute. However, faster printing speeds are an option with a more sophisticated, expensive printer.
• Memory: Most printers come with a small amount of memory -- typically 2-16 megabytes- that can be expanded by the user. Having more than the minimum amount of memory is helpful and faster when printing out pages with large images.