Elements Of Dot Matrix Printing; The Print Head - Epson GX-80 Operating Manual

19
Figure 3-1. A capital T
Chapter3
Elements of Dot Matrix Printing
The Print Head
The GX-80 uses a print head with nine pins or wires mounted
vertically. These pins make the dots by being pushed out of their
resting position. Since this is analogous to shooting with a gun, it is
known as making the pin "fire". 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 1/72nd 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 horizontally across the page, these pins are
fired time after time in different patterns to produce letters, num-
bers, 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 1/60th of an inch, fires the top
pin, moves another 1/60th of an inch, and fires the top pin once
more to finish the letter. All this happens in only 1/lOOth of a
second.
This chapter is for those who want to go into how the printer works.
It is a simple, non-technical explanation of the basics of dot matrix
printing which will give you a better understanding of some of the
later chapters.
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