Hitachi PXR, Service Manual

Page: 208 / 231

7-51
7.6 Miscellaneous
7.6.1 Problems due to inappropriate ink stream position in charged
electrode
>
If the ink stream does not pass through the charged electrode, the following
problems may occur:
(1) The height of printed characters will be larger than standard
(2) Since the ink drops are not charged normally:
- The character quality will degrade (characters are distorted).
- Print fault, such as appearance of crushed characters, will occur.
(3) Since the amount of charge on ink drops that are slightly charged for auto
phase detection among the dots not used for printing is abnormal, those
ink drops will be excessively deflected by the deflecting field and cannot
enter the gutter hole. Therefore, the gutter will be dirty, causing an
alarm of either Ink Drop Charge Too High or No Ink Drop Charge.
> Check the ink stream passing position in charge electrode, and adjust the
electrode so that the ink stream passes through its center.
> Adjustment procedure:
(1) Loosen the screw holding the charge electrode, use the slight clearance to
change the position of electrode, and then tighten the screw.
(2) Use small pliers to apply force to the bent portion of charge electrode for
correction.
Good
Nozzle
Ink
stream
Charge
electrod
Center
Closer
Ink stream drifts to one side.
Closer
Ink stream is oblique