Warmup Control (Vsg Correction) - Ricoh B286 Service Manual

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6.6.7 WARMUP CONTROL (VSG CORRECTION)

In order to prevent the occurrence of dirty background on the first copy after the machine
warms up, the value of Vsg is checked after the upper unit is closed and after the machine
is turned on (or returns from low power mode).
After Closing the Upper Unit
The machine measures Vsg after the upper unit is closed, and recalibrates the ID sensor if
necessary.
If the machine detects Vsg < 2.5 V twice, the machine issues SC401 (ID Sensor Vsg
!
Error.
! If the machine detects Vsg > 2.5 V, it will perform adjustments or issue SC401 as
shown below, based on the value of the Vsg reading. (See the "ID Sensor
Recalibration Table" below.)
After Power On
If the fusing temperature is below 50°C (122°F) after the machine is powered on (or returns
from the low power mode), the machine measures Vsg. The machine compares this Vsg
reading with the PWM value that was stored when the ID sensor was initialized, in order to
determine if the current Vsg value is correct.
! If the machine detects Vsg < 2.5 V twice, the machine issues SC401 (ID Sensor Vsg
Error.
! If the machine detects Vsg > 2.5 V, it will perform adjustments or issue SC401 as
shown below, based on the value of the Vsg reading.
ID Sensor Recalibration
Readings (V)
Vsg < 3.9
Vsg = 3.9 to 4.10
Vsg = 4.1 to 4.2
Vsg = 4.2 to 4.5
Vsg = 4.5 to 4.8
Vsg > 4.8
B286/B289
How the ID Sensor is Recalibrated
PWM value +0.5%
ID sensor is re-calibrated automatically with the stored
PWM value.
PWM value -0.2%
PWM value -0.5%
PWM value -1.0%
SC401 occurs (ID Sensor Vsg Error). For more details see
section 4.2 "SC Code Descriptions."
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