Hitachi PXR, Service Manual

Page: 76 / 231

3-13
3.3.2 EZJ94 board (NH board)
[Function]
- Control of nozzle (charging voltage control, excitation voltage, APH detection, PTC
control and the like) is performed.
- The EZJ94 board is used for the model PXR-D/P, and the EZJ94DH is used for the
model PXR-H. (The red check mark and the blue label are put on the EZJ94DH board
for identification.)
[Setting of switch/check point/LED display and the like]
- Setting of switch
Nozzle size
65µm 40µm, 55µm 100µm
DSW1
Remarks
Both of bits are put on
the bottom.
Set only the right bit to
the up position.
Set only the left bit to
the up position.
- Check point/LED
Reference
number
Name Content
TP1 APH signal Charged amount detection signal of ink drops
TP3 GND Ground (for APH)
TP12 Charging
signal
Character signal charging ink drops
TP13 GND Ground (for charge/excitation)
TP14 Excitation
signal
Sine wave signal applied to a nozzle
TP15 PTC signal PTC drive signal
LED1 APH signal For APH signal check with eyes
[Note at the replacement]
- When replacing boards, be sure to turn off the power.
- Set up DSW 1 according to the nozzle diameter.
- After replacing the board, confirm the charging voltage.
- Perform the excitation adjustment.
- Perform the auto phase gain adjustment.
[EZJ94 board external views]
With respect to the
charging voltage
confirmation, refer to
“2.3.2 Charging voltage
confirmation”.
With respect to the auto
phase gain adjustment,
refer to “2.3.4 Auto phase
gain adjustment”.
Mark
Mark
Mark
The EZJ94 board has a portion where high voltage is applied. When performing
the adjustment in a state where the Electric Component cover is opened, be fully
careful about an electric shock.
Caution against an electric shock
With respect to the
excitation adjustment,
refer to “2.3.1 Excitation
adjustment”.
Protective
cover
TP14: Excitation signal
TP13: Ground
TP12: Charging signal
TP3: Ground
TP1: APH signal
TP15: PTC signal
DSW1
Three setscrews
Two studs for fixing
a protective cover
Three setscrews
Three setscrews
Two studs for fixing a
protective cover
(Marked side
）
The red check mark and
the blue label are put on
the EZJ94DH board for
identification.
LED1