Hitachi UX Twin Nozzle, Service Manual

Page: 325 / 355

6-83
6.5.2 Chipped print (upper dots)
[Caution]
Do not repeat the nozzle backwash procedure more than two times.
If it is repeated in excess, the ink becomes thin, thereby
causing disordered prints.
If the ink is thin and printings become disordered, replace the ink.
Missing
dots
Direction of
deflection
Yes
Since it is conceivable that the
ink flow path may be clogged,
replace the ink filter and MGV
filter, clean joints, backwash
the nozzle, and disassemble
and clean the nozzle.
No
Chipped print
Adjust the ink stream
position so that the ink
stream is centered with
respect to the gutter.
No
Is the ink stream
positioned at the
center of the gutter?
Yes
Is the ink pressure
lower than the
specified limit?
No
Yes
Is it possible to make
normal prints with the
ink pressure raised
above the specified
limit?
Sprinkle the makeup over
the deflection electrode to
clean it.
Yes
Is there any ink or dirt
buildup on the plus
deflection electrode?
Yes
Yes
No
Is the charge
voltage properly
adjusted?
Adjust the charge voltage.
Adjust the ink
pressure until it is
within the limits.
Can the ink pressure be
adjusted?
No
Yes
Resume the
operation.
Replace the ink.
Can normal
prints be made?
No
Yes
Provide pressure relief and
then replace the pressure-
reducing valve.
Is the ink stream
positioned at the center
of the charge electrode?
No
Adjust the ink
stream position.
No