Hitachi HT-4139-28 Maintenance Manual page 56

7.8.5.3 Ultra sonic sensor level
NOTE: The ultra sonic sensor detects dual paper feed by checking its level reduced by air layer between
papers.
The level of the ultra sonic sensor is mostly constant.
Check if it works correctly by changing the number of sheets on the feeding mechanism
The figure below shows an example of level change during paper feeding.
FF
EC
threshold
37
0
Single sheet
Value for more than one
(1) Confirm the best gain of the Ultra sonic sensor.
(2) "Level of ultrasonic sensor" in the "Information
display of Photo / Video level / SW/ Supersonic
sensor" dialog, specify parameters and click the
"RUN" button.
･Gain of ultrasonic sensor: xx（Specify the gain
confirmed at (1)）
･Motor: Main(default)
･Motor speed: 0.822 m/s(default)
･Sensor sending wave: Exists (default)
･Motor operation: Detected（default）
･Lamp mode 1: Light on (default)
･Lamp mode 2: Light off
If necessary, change parameter and perform this.
(3)Level of ultrasonic sensor will be displayed every a
few second
To fix the screen, click the "Pause" button.
The "Pause" button will be changed to the "FINISH"
button. To finish display, click the "FINISH" button.
（AF）
（19）
Dual sheet
Single sheet
Refer to "7.8.4.4 Ultra Sonic Sensor"
no sheet
threshold < Level
Judgment 0
None or 1
threshold > Level
judgment1
more than 2
Value for more than two
REV0 2010.02.15
-H7-23-