Color Printer
A printer capable of printing more than one color. Most color printers are based on the CMYK color model, which prints in four basic colors: cyan, magenta, yellow, and black. By printing combinations of different colors close to each other (or, in the case of thermal dye transfer printers, on top of each other), the CMYK model can simulate most other colors (except for special colors such as fluorescent yellow). This is the same technique used in process color offset printing, which is the technology used to print most color books, magazines, and other paper materials. Some lower-price printers use only three colors — cyan, magenta, and yellow — but these printers cannot print true black and their colors tend to be a bit faded.
Color printers use a variety of techniques to lay down the different colors:
· Thermal dye transfer printers, also called dye sublimation printers, heat ribbons containing dye and then diffuse the dyes onto specially coated paper or transparencies. These printers are the most expensive and slowest, but they produce continuous-tone images that mimic actual photographs. Note that you need special paper, which is quite expensive. A new breed of thermal dye transfer printers, called snapshot printers, produce small photographic snapshots and are much less expensive than their full-size cousins.
· Thermal wax transfer printers use wax-based inks that are melted and then laid down on regular paper or transparencies. Unlike thermal dye transfer printers, these printers print images as dots, which means that images must be dithered first. As a result images are not quite photo-realistic, although they are very good. The big advantages of these printers over thermal dye transfer printers are that they don’t require special paper and they are faster.
· Solid ink-jet printers , also called wax jet or phase change printers, work by melting dyed wax and then spraying it on paper. This produces bright colors on virtually any type of paper. The downside to solid ink-jet printers is that they are slow and relatively expensive.
· Color laser printers laser_printer use the same principle as monochrome laser printers, but they include four toners rather than one. Although laser printers produce better quality output than ink-jet printers, they are also much more expensive.
· Color ink-jet printers are the least expensive color printers. They contain three or four separate nozzles, each of which sprays a different color of ink.
Color printers are sometimes divided into the following categories:
· Bi-level: Each of the ink colors is either on or off for each dot. Different colors are produced by dithering.
· Continuous-tone: Each dot can contain a mixture of colors.
· Contone: Provides more shades per dot than bi-level printers, but less than continuous-tone printers.