Toshiba e-STUDIO4500c Service Manual page 801

August 2006
Calculate Development Gamma
The laser diodes write a 10-grade potential sensor pattern on each drum. To make
the different densities, the machine changes the PWM duty of the laser diodes.
At this step, the development gamma (development capacity) is measured. The
necessary potentials are calculated. Next, the target values (necessary potentials)
for Vd (charge potential), Vb (development bias), and Vpl (drum potential after
exposure) are retrieved from the Potential Reference Table.
At this time:
Development gamma must be in the range 0.3 to 6.0 V
Development start voltage (Vk) must be in the range –150 to 150 V. This
development start voltage is used to indicate whether the developer has
deteriorated. However, this is only a rough measurement that can be affected by
ambient conditions and the condition of other electrical components.
ID Sensor Pattern Detection Errors
SC Codes SP3821 Procon OK?
SC410~SC413
SC414~SC417
Adjust for Residual Potential
The laser unit fires at full power (PM = +127, PWM = 63) to compensate for a
possible high residual potential on the drum. Next, the amount of residual potential
is detected, and the charge is adjusted to achieve the target potential.
The detected Vr must be less than –200V.
Vr (Residual Potential) Errors
SC Codes SP3821 Procon OK?
SC432~SC435
Adjust Vd
This step adjusts Cdc, the charge applied to adjust dc bias target Vd . Vd is the
targeted bias after Vr (residual potential correction).
The targeted potential of Vd must be within 5V.
Vd (Development Bias) Errors
SC Codes SP3821 Procon OK?
SC420~SC423
55~56, 59 See "Process Control Troubleshooting" in
Section "4. Troubleshooting".
57~58
62 See "Process Control Troubleshooting" in
Section "4. Troubleshooting".
63 See "Process Control Troubleshooting" in
Section "4. Troubleshooting".
6-85
PROCESS CONTROL
For More Details:
For More Details:
For More Details:
B132D925.WMF