Toner Supply In Abnormal Sensor Conditions; Toner Near End/End Detection And Recovery - Ricoh K-C3 Service Manual

B245/B276/B277/B268/B269 Service Manual
The value of "t" can be changed using SP 2922 (default: 0.4 second)
The value of "T" can be changed using SP 2923 (default: 30 seconds)
T (30) means that toner is supplied intermittently in a 1/3 duty cycle (1 s on, 2 s off)
for 30 seconds

Toner Supply in Abnormal Sensor Conditions

ID Sensor
Readings are abnormal if any of the following conditions occur:
Vsg 2.5V
Vsg < 3.5V when maximum power (979) is applied
Vsp 2.5V
(Vsg – Vsp) < 1.0V
Vt 4.5V or Vt 0.2V
The above ID sensor values can be checked using SP 2221.
When this is detected, the machine changes the value of Vref to 2.5 V then does the toner
density control process (in a similar way to sensor control mode 2).
No SC code is generated if the ID sensor is defective.
TD Sensor
The TD sensor output is checked every copy. If the readings from the TD sensor become
abnormal, the machine changes the toner density control mode to fixed supply mode 2, and
the toner supply amount per page is always 200 ms, regardless of the value of SP 2925. If
the machine detects the TD sensor error condition 10 times consecutively, an SC code is
generated (SC390) and the machine must be repaired.

Toner Near End/End Detection and Recovery

The toner near end and end conditions are detected using the Vt and Vref values, in a
similar way to toner density control.
This is done in all toner supply modes except for fixed mode 2, when toner end is not
detected.
Toner Near End Detection
If Vt is at level 6 (see the table on the previous page) five times consecutively, the machine
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