Toner Density Detection By The Toner Sensor; Toner Density Control - Kyocera Mita KM-1810 Service Manual

(2) Toner density detection by the toner sensor

The toner sensor (TNS) detects the toner density. As the developer passes by the sensor section of the toner sensor, the
toner sensor detects the ratio of toner to carrier in the developer and converts it into a voltage. When more toner is used,
the ratio of toner to carrier decreases and the toner sensor output voltage increases. When the ratio drops below the
specified value, the increase in toner sensor output voltage triggers toner replenishing. When toner is added and the ratio
of toner to carrier returns to normal, the toner sensor output voltage drops to the point where toner replenishing stops.

(3) Toner density control

Toner sensor
output voltage (V)
Toner empty
detection level (3.2V)
Toner feed start level
(2.2V)
a: If the toner sensor output voltage exceeds the toner feed start level 15 s after the drive motor (DM) has turned on
(end of toner empty detection inhibit time), the toner feed motor (TFM) turns on to replenish toner.
b: As toner is replenished, the toner sensor output voltage falls until it drops below the toner feed stop level and
replenishing stops.
c: When the toner sensor output voltage exceeds the toner empty detection level after toner replenishing is carried out,
the toner being replenished message appears disabling copying and forced toner feed starts. If the toner sensor
output voltage fails to fall to the toner feed stop level within 180 s of the start of forced toner feed, the toner request
message appears.
d: When toner is replenished, the toner sensor output voltage falls until it drops below the toner feed stop level and
replenishing stops. After 60 s aging (15 s while copying) the toner being replenished message disappears and
copying is enabled.
e: After replacing the toner container and the waste toner tank, the toner feed motor (TFM) turns on to replenish toner.
f: When toner is replenished, the toner sensor output voltage falls until it drops to the toner feed stop level. The toner
being replenished message disappears and replenishing stops.
Toner being replenished message
(forced toner feed)
180 s
ab c d
Figure 2-1-15 Toner density control
Toner request message
(Toner container and
waste toner tank to be replaced.)
Copying
e f
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