Toner Supply Control - Ricoh A028 Service Training Manual

1 July 1994
2.10.3 Toner supply operation
The toner density reference value (toner supply
threshold 1) is determined by the ratio V
compared with the toner density sensor output. If the
output of the sensor is lower by 0.04 volts than the
reference value during copying, the toner supply motor
is turned ON.
The toner supply motor turns at the toner supply rate of
15%, 30%, 45%, or 60% as selected by the service tool.
The motor is stopped when the output of the toner
density sensor meets the toner density sensor reference
value.

Toner supply control

Toner supply
threshold 1
Toner supply
threshold 2
Toner supply
limit
Toner density sensor output
Toner density sensor
Toner supply threshold 1
Toner supply threshold 2
Toner supply limit
Toner density sensor output
1.
If the toner density sensor output falls below threshold 2 during copying, the toner supply
starts at the predetermined rate.
2.
If the sensor output exceeds threshold 1, the toner supply stops. However, when copying
ends, toner supply stops even if threshold 1 is not exceeded.
3.
If toner consumption cannot be covered by the predetermined toner supply rate during 25
copies, the rate is increased by one step. During more 25 copies, if it cannot be covered,
the rate is increased by one step again. When this does not succeed, copying stops
temporarily and the machine keeps on supplying toner at the maximum supply rate (toner
quick supply mode).
4.
If before entering the toner quick supply mode the toner near-end sensor detects a low toner
condition, the toner end indicator is displayed and copying is stopped.
5.
Toner supply threshold 1 is changed by 0.12 volts according to the ID sensor output.
NOTE
Threshold 1 (Actual Target T.D. value shown in service tool [4-02]) is changed in a range of ± 0.74
volts from the "Setting Target T.D." value according to the ID sensor output. Therefore, if the
"Setting Target T.D." is abnormal, a proper level of threshold 1 might not be obtained. Do not press
the "Developer Forming" key in service tool [4-02] without carrying out setting C. (The "Developer
Forming" key in service tool [3-04] does not change the "Setting Target T.D.")
/V , and it is
SG SP
Toner supply OFF
Toner supply ON
Toner density sensor reference
voltage determined by ID sensor.
Threshold 1 - 0.04 (V)
Threshold 1 - 0.12 (V)
Measured voltage by toner density
sensor
2-77
Toner Density Control