Epson 4500 - Manual (Page 117)

Graphics
I n c o m e B r e a k d o w n
M a r k e t i
A d v e r t i
S a l a r i e
P r o d u c t
i t
The Print Head
To understand dot graphics you need to know a little about how your
printer’s print head works.
The print head has 24 pins. As the print head moves across the page,
electrical impulses cause the pins to fire. Each time a pin fires, it strikes
the inked ribbon and presses it against the paper producing a small dot.
As the print head moves along, the pins fire time after time in different
patterns forming letters, numbers, and symbols.
Because the dots overlap each other both horizontally and vertically in
Letter Quality mode, it is difficult to see the individual dots. Instead,
the letters and symbols seem to be made up of unbroken lines.
In order for the dots to overlap vertically, the pins in the print head are
in more than one column, but the intelligence of the printer handles the
timing of pin firings so that the effect is that of 24 pins arranged in a
single vertical column.
Dot patterns
The print head is able to print graphics as well as text because graphic
images are formed by the printer in about the same way that pictures in
newspapers and magazines are printed. If you look closely at a
4-10 Software and Graphics