B245/B276/B277/B268/B269 Service Manual 18-Jan-06
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The four-toner density control modes are as follows.
Sensor control 1
Mode Sensor control 1 (SP 2921, “0”): Normally use this setting only
Toner supply decision Compare Vt with a reference voltage (Vts or Vref)
Toner control process
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).
Toner supply amount Varies
Toner end detection Performed
Sensor control 2
Mode
Sensor control 2 (SP 2921, “1”): For designer’s use only; do not use
in the field
Toner supply decision Compare Vt with a reference voltage (Vts)
Toner control process This toner control process is the same as sensor control 1 mode.