Toshiba e-STUDIO650 Service Handbook page 237

Defective area Step
Main charger output 8
Developer bias output 9
Increasing toner density 10 Is the performance of the auto-toner
11 Is the toner density high?
Image quality sensor/ 12 Are the image quality sensor and the
Surface potential sensor
Drum cleaning blade 13 Is the drum cleaned properly?
Note 1:
If the output from the main charger or the developer bias is abnormal, replace the high-voltage transformer with a new one and
output the chart again. If the output stays abnormal, check if the harness connecting the LGC board and high-voltage
transformer is open-circuited, if the power supply is normal and if the main charger wire is dirty.
Note 2:
Toner density correcting method
Change the setting value 'Toner density life correction setting (08-414)' (6 is the default setting.)
3: Appox. 1.5% lower than the current value
4: Appox. 0.8% lower than the current value
5: Appox. 0.3% lower than the current value
6: The current value (Default setting)
<Caution for correction>
When increasing or decreasing the toner density too much, the image may become poor or the life of developer material,
cleaner, photoconductive drum and fuser unit, etc. may shorten. Therefore it is not recommended to correct (to shift) the toner
density basically. If it is shifted, make sure that the image may be improper in a few minutes after shifting.
JUNE 2002 © TOSHIBA TEC
Check Items
Is the setting value proper?
Is the main charger output normal?
Is the setting value proper?
Is the developer bias output normal?
sensor control normal?
surface potential sensor normal?
7: Appox. 0.3% higher than the current value
0: Appox. 0.5% higher than the current value
1: Appox. 0.8% higher than the current value
2: Appox. 1.5% higher than the current value
5 - 109
Prescription
If the setting value is out of specification,
adjust it.
If the output is not normal, check the
circuits. (Note 1)
If the setting value is out of specification,
adjust it.
If the output is not normal, check the
circuits. (Note 1)
Check the performance of the
auto-toner sensor.
Adjust the toner density.
(Note 2: See the toner density
correcting method.)
Check the performance of the image
quality sensor and the surface potential
sensor. (See the troubleshooting
related with the image quality control.)
See the troubleshooting for the
poor cleaning.)
e-STUDIO550/650/810 TROUBLESHOOTING
Remarks