Hitachi UX Twin Nozzle Service Manual page 326

6.5.3 Varying character height
Optimize the clearance
between the nozzle head
end and print target.
Adjust the character
height setting.
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.
Yes
Are normal prints
obtained?
No
Replace the ink.
Adjust the charge voltage.
[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.
Varying character
height
Is optimum clearance
No
provided between the
nozzle head end and print
target?
Yes
Was the character
Yes
height setting
changed?
No
Is the ink pressure
within the specified
range?
yes
Is the normal height
Yes
obtained when the ink
pressure is raised above
the specified limit?
No
Is the ink stream
positioned at the center
of the charge electrode?
Yes
Is the charge
No
voltage properly
adjusted?
Yes
Resume the
operation.
6-84
No
Can the ink pressure be
adjusted?
No
Provide pressure relief and
then replace the pressure-
reducing valve.
No
Adjust the ink
stream position.
Yes
Adjust the ink
pressure until it is
within the limits.