Hitachi IJ PH, Service Manual

Page: 191 / 211

6-54
6.6.2 Problems due to inappropriate ink stream position to gutter
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If the ink stream does not enter the center of gutter, the following problems may
occur:
(1) The ink stream hits the inner wall of gutter inlet and “splash” occurs. This
will dirty the gutter, causing either Ink Drop Charge Too High or No Ink
Drop Charge.
(2) Ink accumulates on outer circumference of gutter. The ink stream collides
with this sediment, which will cause the lower dots of printing to be missing.
(See section 6.5.1 for details.)
(3) The ink drops charged for auto phase detection are deflected by the deflecting
field. Therefore, the ink stream position is deflected to the positive electrode
from the center of gutter: If A is larger than 2B as shown in figure below, the
ink drops may hit the end surface of gutter.
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Check the ink stream position, and perform adjustment making sure that the ink
stream enters the center of gutter.
Good
Ink
stream
Negative
deflection
electrode
Gutter
Center
End
surface of
gutter
Center
Inner wall
of gutter
inlet
A>2xB