Toshiba e-STUDIO4500c Service Manual page 800

PROCESS CONTROL
First, a check confirms that all the PCU are set correctly.
NOTE: Please keep in mind that all the readings and calculations described below
are done in each of the four PCUs. For simplicity, however, the discussions
are limited to what occurs in a single PCU.
Detect Vdhome
A charge of –700V is applied to the drum. The potential sensor detects the
potential of the drum and checks if the potential sensor, drum, and charge roller are
functioning normally.
If the charge is within the range –700V to –500V, the drum is functioning normally.
Potential Sensor Calibration Errors
SC Codes SP3821 Procon OK?
SC436~SC439
Adjust AC Charge
The machine finds the current that is necessary for the optimum AC charge (Vpp).
The optimum charge depends on the ambient temperature and humidity. The
optimum charge for each temperature and humidity range is set with SP2204 (ACC
Charge Correction).
Insufficient charge causes white spotting and too much charge causes toner to film
on the surface of the drum.
This check ensures that the average value of Vpp after 20 samplings is Vpp > 2.8
kV.
AC Charge Errors
SC Codes SP3821 Procon OK?
SC316~SC319
Adjust Vsg
Before the gradated patterns are read, the strength of the ID sensor output (LED
PWM) is adjusted to bring the value of Vsg_reg to the specified value.
An abnormal condition is detected when:
Before Vsg adjustment begins, Vsg_reg < 0.5V
After Vsg adjustment, Vsg_reg cannot be adjusted to 4.0 0.2V
ID Sensor Errors
SC Codes SP3821 Procon OK?
SC400, SC418
15~17 See "Process Control Troubleshooting" in
Section "4. Troubleshooting".
31~32 See "Process Control Troubleshooting" in
Section "4. Troubleshooting".
21~23 See "Process Control Troubleshooting" in
Section "4. Troubleshooting".
6-84
For More Details:
For More Details:
For More Details:
August 2006