Ricoh K-C3 Service Manual page 222

B245/B276/B277/B268/B269 Service Manual
The four-toner density control modes are as follows.
Sensor control 1
Mode
Toner supply decision Compare Vt with a reference voltage (Vts or Vref)
Toner control process
Toner supply amount
Toner end detection
Sensor control 2
Mode
Toner supply decision Compare Vt with a reference voltage (Vts)
Toner control process
Toner supply amount
Toner end detection
Fixed control 1
Mode
Toner supply decision Compare Vt with a reference voltage (Vts or Vref)
Sensor control 1 (SP 2921, "0"): Normally use this setting only
Toner is supplied to the development unit when Vt is higher than
the reference voltage (Vts or Vref). This mode keeps the Vref value
for use with the next toner density control.
Vts is used for the first toner density control after a new PCU has
been installed, until it has been corrected with the ID sensor output.
Vref is used after Vts has been corrected with the ID sensor output
voltage (corrected during the first toner density control for a new
PCU).
Varies
Performed
Sensor control 2 (SP 2921, "1"): For designer's use only; do not
use in the field
This toner control process is the same as sensor control 1 mode.
However, the reference voltage used is always Vts.
Varies
Performed
Fixed control 1 (SP 2921, "2"): For designer's use only; do not use
in the field
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