Correcting The Toner Sensor Control Voltage - Kyocera Mita KM-1530 Service Manual

(4) Correcting the toner sensor control voltage

The toner sensor control voltage is corrected based on the absolute humidity and the total drive motor time so that the
toner density is kept constant regardless of the changes in humidity and the total drive motor time.
Toner sensor control voltage after correction = A + B + C
A: Toner sensor control voltage before correction (value set by maintenance item U131)
B: Correction data based on the absolute humidity
C: Correction data based on the total drive motor time
• Correction based on the absolute humidity
Correction data
+15
0
-15
0
a: When the absolute humidity is between 0 and 1.5 g/m
voltage.
b: When the absolute humidity is between 1.5 and 4.0 g/m
absolute humidity.
c: When the absolute humidity is between 4.0 and 10.0 g/m
d: When the absolute humidity is between 10.0 and 18.0 g/m
absolute humidity, reducing the toner sensor control voltage.
e: When the absolute humidity exceeds 18.0 g/m
toner sensor control voltage.
Computing the absolute humidity
The humidity sensor (HUMSENS) converts the relative humidity detected by the humidity sensing element into a voltage
and sends it to the main PCB (MPCB). The main PCB (MPCB) computes the absolute humidity based on this HUMSENS
signal and the temperature (ETTH signal) detected by the external temperature thermistor (ETTH).
Figure 2-1-18 Absolute humidity computation block diagram
1.5 4.0 10.0
Figure 2-1-17 Correction based on the absolute humidity
3 , a constant value of +15 is added to the toner sensor control
3 , the correction data becomes a constant value of –15, decreasing the
ETTH
Humidity
sensing
element
HUMSENS
19.0
Absolute humidity (g/m
3 , the correction data is reduced according to the rise in
3 , the correction data becomes 0.
3 , the correction data is decreased according to the rise in
MPCB
4 ETTH
CN7-1
3 GND
CN7-2
2 HUMSENS
CN7-3
1 DC5V
CN7-4
2AV/X
3
)
2-1-13
2-1