Saturn S300 Series Service Manual page 130

Maintenance
Print Quality (Nozzle Drive Set-up Procedure)
Introduction
Definition: Foldback
Procedure
Nozzle
Plate
Figure 6-20. Locating the Breakoff Point
The purpose of the nozzle drive set-up procedure is to locate the
"drive window," or the nozzle drive range that yields good print
quality, and set the nozzle drive inside the drive window.
Complete the nozzle drive set-up procedure immediately after you
complete the ink stream calibration procedure and set the ink
flow time.
The drive window for one particular printhead may vary from
another printhead due to differences in inks and variations in
nozzles. This procedure will work for all ink types and all SATURN
nozzles.
The nozzle drive set-up procedure requires that you find the
"foldback" nozzle drive level. Foldback is the point at which the
breakoff point just begins to move toward the front end of the
printhead as you increase the nozzle drive level. The drive
window is always below foldback. This concept is explained in
depth in the procedure.
CAUTION: The following procedure may have to be repeated if
the ambient temperature changes substantially.
1. Perform the viscosity calibration procedure (refer to page 6-24)
to set the ink pressure and the set-point ink flow time.
2. Enter a text message using the font you intend to print.
3. Find the foldback nozzle drive level using the following
procedure.
a. Set the nozzle drive level at 1 and increase the nozzle
drive level until the breakoff point is just inside the charge
electrode window. Observe the position of the breakoff
point inside the charge electrode window with a loupe or
magnifying glass. (Refer to Figure 6-20 for an example of
what the ink stream may look like inside the charge
electrode.)
Breakoff Point
6-27
Front end
of Printhead
Direction of
Ink Stream