Correcting The Toner Sensor Control Voltage - Kyocera Mita KM-1810 Service Manual

2A1/2

(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
+8
0
-5
0
a: When the absolute humidity is between 0 and 12 g/m
decreases the toner sensor control voltage.
b: When the absolute humidity is between 12 and 91 g/m
absolute humidity.
c: When the absolute humidity is 91 g/m
d: When the absolute humidity is between 91 and 321 g/m
absolute humidity, which increases the toner sensor control voltage.
e: When the absolute humidity exceeds 321 g/m
the 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).
2-1-14
c
b
a
12 91
Figure 2-1-16 Correction based on the absolute humidity
3 , the correction data becomes 0.
3
, the correction data becomes a constant value of +8, which increases
HUMSPCB
ETTH
Humidity
sensing
element
HUMSENS
Figure 2-1-17 Absolute humidity computation block diagram
e
d
321
Absolute humidity (g/m
3
, the correction data becomes a constant value of –5, which
3
, the correction data is increased according to the rise in
3 , the correction data is increased according to the rise in
MPCB
4 ETTH
CN9-1
3 GND
CN9-2
2 HUMSENS
CN9-3
1 5 V DC
CN9-4
3
)