Ricoh K-C3 - Toner Supply in Abnormal Sensor Conditions

B245/B276/B277/B268/B269 Service Manual 18-Jan-06
235
For sensor control modes 1 and 2, the toner supply motor on time is decided by the following
factors.
 Vt
 Vref or Vts
 TD sensor sensitivity (coefficient: S, value is 0.4)
There are seven levels for toner supply motor on time as shown below.
Level Decision Motor On Time (seconds)
1 (Vts or Vref) < Vt (Vts or Vref) + S/16 t (0.4)
2 (Vts or Vref) < Vt (Vts or Vref) + S/8 t x 2 (0.8)
3 (Vts or Vref) < Vt (Vts or Vref) + S/4 t x 4 (1.6)
4 (Vts or Vref) < Vt (Vts or Vref) + S/2 t x 8 (3.2)
5 (Vts or Vref) < Vt (Vts or Vref) + 4S/5 t x 16 (6.4)
6 Vt (Vts or Vref) + 4S/16 (near-end) T (30); see note 3
7 Vt (Vts or Vref) + S (toner end) T (30); see note 3
 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.