Hitachi UX Twin Nozzle, Service Manual

Page: 335 / 355

6-93
6.5.11 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
make the gutter dirty, causing either excessive charging or no charge on ink
drops.
(2) Ink drops which hit the gutter accumulates around gutter, and then the character
quality will degrade by missing the lower dots of the printing.
(3) The ink drops charged for auto phase detection are slightly deflected by the
deflecting field. Therefore, if the ink stream position is bent to the positive
electrode side from the center of gutter as shown in the figure below, A will be
larger than 2xB. In this case, the ink drops may hit the end of the gutter.
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Check the ink stream position, and adjust the ink stream goes through the center of
gutter.
Good
Negative
deflection
electrode
Gutter
A>2xB
Ink
stream