InkjetPrinter

No matter where you are reading thisarticle, you most likely have a printer nearby. And there's a very good chancethat it is an inkjet printer. Since their introduction in the latterhalf of the 1980s, inkjet printers have grown in popularity and performancewhile dropping significantly in price.

An inkjet printer is anyprinter that places extremely small droplets of ink onto paper to create animage. If you ever look at a piece of paper that has come out of an inkjetprinter, you know that:

• The dots are extremely small (usually between 50 and 60 microns in diameter), so small that they are tinier than the diameter of a human hair (70 microns)!
• The dots are positioned very precisely, with resolutions of up to 1440x720 dots per inch (dpi).

The dots can have different colors combined together to create photo-qualityimages. In this edition of HowStuffWorks, you will learn about thevarious parts of an inkjet printer and how these parts work together to createan image. You will also learn about the ink cartridges and the special papersome inkjet printers use.

First, let's take a quick look at the various printer technologies.

Impact vs. Non-impact

There are several major printertechnologies available. These technologies can be broken down into two maincategories with several types in each:

• Impact - These printers have a mechanism that touches the paper in order to create an image. There are two main impact technologies:
  • Dot matrix printers use a series of small pins to strike a ribbon coated with ink, causing the ink to transfer to the paper at the point of impact.
  • Character printers are basically computerized typewriters. They have a ball or series of bars with actual characters (letters and numbers) embossed on the surface. The appropriate character is struck against the ink ribbon, transferring the character's image to the paper. Character printers are fast and sharp for basic text, but very limited for other use.
• Non-impact - These printers do not touch the paper when creating an image. Inkjet printers are part of this group, which includes:
  • Inkjet printers, which are described in this article, use a series of nozzles to spray drops of ink directly on the paper.
  • Laser printers, covered in-depth in How Laser Printers Work, use dry ink (toner), static electricity, and heat to place and bond the ink onto the paper.

• Solid ink printers contain sticks of wax-like ink that are melted and applied to the paper. The ink then hardens in place.
• Dye-sublimation printers have a long roll of transparent film that resembles sheets of red-, blue-, yellow- and gray-colored cellophane stuck together end to end. Embedded in this film are solid dyes corresponding to the four basic colors used in printing: cyan, magenta, yellow and black (CMYK). The print head uses a heating element that varies in temperature, depending on the amount of a particular color that needs to be applied. The dyes vaporize and permeate the glossy surface of the paper before they return to solid form. The printer does a complete pass over the paper for each of the basic colors, gradually building the image.
• Thermal wax printers are something of a hybrid of dye-sublimation and solid ink technologies. They use a ribbon with alternating CMYK color bands. The ribbon passes in front of a print head that has a series of tiny heated pins. The pins cause the wax to melt and adhere to the paper, where it hardens in place.
• Thermal autochrome printers have the color in the paper instead of in the printer. There are three layers (cyan, magenta and yellow) in the paper, and each layer is activated by the application of a specific amount of heat. The print head has a heating element that can vary in temperature. The print head passes over the paper three times, providing the appropriate temperature for each color layer as needed.

Out of all of these incredibletechnologies, inkjet printers are by far the most popular. In fact, the onlytechnology that comes close today is laser printers.

From howstuffworks