The Written Word
Since ancient times it has been important to record thoughts so they may be passed on accurately. This process was made easier by the printing press. However, the problem with the press was that it took hours to set up one page for printing.
Years later with the invention of the typerwriter it became easy to make type on paper. However once something was down on the paper, it could not be changed. Eventually, the personal computer and the word processor came along. These magic machines allowed text to be edited on screen. However getting the text, pictures, and spreadsheets people were now creating was the new challenge. The first types of printers are what is known as dot matrix. That is they use dot's to from the characters. For Example:
This is very much enlarged and exaggerated but you get the idea. One drawback of this format is it is more suited to text then it is to graphics. On top of that, color printers of this type are impractical. The way the dot matrix system works involves hundreds of little pins. When each pin stamps down it hits an ink ribbon, pushing it against the paper in that spot. That is where the Dot part of the word comes from. Matrix means a plate used for casting type faces. So Dot Matrix is simply a set of dots that make type.
A process similar to Dot Matrix but much more precise is the use of ink jet printers. These printers each have four ink nozzles, or jets as they are called. There are four jets in all. Each jet has it's own special color: yellow, cyan, (red) magenta, (blue) and black. By laying down tiny dots of these colors in the right proportion, any color can be created. The density and where the dots are placed are controlled by a microprocessor (small computer) inside the printer itself.
Another type of printer is the laser printer. This printer uses a tiny laser bouncing off a computer controlled mirror. This laser is then bounced onto a metal drum. It makes the design of what the image is, only in reverse. Where the laser touches the drum, static electricity makes a special ink called toner stick to it. Then as a piece of paper is brushed against the drum the toner is transfered to it. Then the paper is pressed and heated so the toner becomes permanent.
