Chapter2 Elements of Dot Matrix Printing This chapter is for those who want to know something about how your printer works. It's a simple, non-technical explanation of the basics of dot matrix printing that will help you understand some of the later chapters. The Print Head The MPS 1000 uses a print head with nine pins or wires mounted vertically. Each time a pin is fired, it strikes the inked ribbon and presses it against the paper to produce a dot. This dot is about 1I72nd of an inch in diameter. The size varies slightly depending upon the age of the ribbon and the type of paper used.
As the head moves horizon- tally across the page, these pins are fired time after time in different patterns to produce letters, numbers, symbols or graphics. For example, to print a pica capital T, the head fires the top pin, moves 1/60th of an inch, fires the top pin again, moves 1/60th of an inch, fires the top seven pins, moves 1I60th of an inch, fires the top pin, moves another 1I60th of an inch, and fires the top pin once more to finish the letter. All this happens in only 1 I lOOth of a second. Figure 2-1. A capital T 25