Gestetner B070 Service Manual page 585

TD Sensor Calibration (Vref)
Next, Vref (TD sensor reference voltage) is updated using the latest calibration
values from the ID sensor.
Vref is updated to stabilize the concentration of toner in the development unit. By
shifting the value of Vref, the density of the ID sensor pattern image is controlled.
Toner supply control is covered in the Development and Toner Supply section.
Vref is determined from a table in the machine software, using the following values:
• Vsp/Vsg
Vsp: ID sensor output when checking the ID sensor pattern.
Vsg: ID sensor output when checking the bare drum.
• Vref-Vt:
Vref is the TD sensor reference voltage
Vt is the current output voltage of the TD sensor.
NOTE: If the ID sensor could not be calibrated during the latest process control
(when measuring Vsg), then the previous ID sensor value is used.
If the ID sensor output is abnormal when measuring Vsp, SC350, 351, or
352 is issued, and Vref is not updated (the machine uses the previous
value).
SM
CÓPIA NÃO CONTROLADA
6-69
CÓPIA NÃO CONTROLADA
DRUM UNIT
B070/B071