Hitachi UX Twin Nozzle, Service Manual

Page: 327 / 355

6-85
6.5.4 Increased character distortion
[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.
Increased character
distortion
Optimize the clearance
between the nozzle head
end and print target.
No
Is optimum clearance
provided between the
nozzle head end and print
target?
Yes
Is the ink pressure
higher than the
specified limit?
No
Yes
Adjust the ink
pressure until it is
within the limits.
Replace the ink.
Has the operating
time exceeded the ink
shelf life?
No
Yes
Adjust the excitation
voltage and pressure to
ensure proper ink drops
generation.
Are ink drops
properly generated?
Yes
No
Yes
Is the normal height
obtained when the ink
pressure is raised above
the specified limit?
No
Can the ink pressure
be adjusted?
No
Yes
Resume the
operation.
Adjust the charge voltage.
Is the charge
voltage properly
adjusted?
Yes
No
Replace the ink.
Are normal
prints obtained?
No
Yes
Provide pressure relief and
then replace the pressure-
reducing valve.
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
Is the ink stream
positioned at the center
of the charge electrode?
Adjust the ink
stream position.
No