Epson SQ-2000, Operating Manual

Page: 87 / 181

When the SQ-2000 produces 8-dot graphics options, it prints
with every third nozzle.
Each byte of data received controls the nozzles for only one
vertical column of dots. This means you have to send the printer
more information when printing dot graphics, but it also means
that you have full control over what each print nozzle is doing.
A byte of data contains eight binary digits, or bits. Each bit
controls
one
of the eight nozzles used for 8-dot graphics. Figure
6-l shows how a graphics data byte controls eight print head
nozzles.
Graphics data byte
Most significant
b i t
Least significant
b i t
Print head
dot nozzles
Figure 6-Z. Graphics data byte and print head nozzles
Creating binary bit patterns like this may be easy for compu-
ters, but it’s difficult for humans. There is an easier way to create
graphics data bytes. If you assign each of the print head nozzles a
value, the value of a graphics data byte is the sum of the values of
the nozzles that you want to print (see Figure 6-2).
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