Toshiba e-studio600 Service Manual page 472

Defective area
Developer bias output
Decreasing toner density
Image quality sensor/ Sur-
face potential sensor
Main charger
Note: Note:
1. Toner density correcting method
Change the setting value 'Toner density life correction setting (08-414)' (6 is the default setting.)
0: Appox. 0.75% lower than the current value
1: Appox. 0.50% lower than the current value
2: Appox. 0.25% lower than the current value
3: The current value (Default setting)
4: Appox. 0.15% higher than the current value
5: Appox. 0.25% higher than the current value
6: Appox. 0.50% higher than the current value
7: Appox. 0.75% higher than the current value
<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. There-
fore 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.
e-STUDIO520/600/720/850 TROUBLESHOOTING
Step Check items
9 Is the setting value proper?
Is the developer bias output normal?
10 Is the Auto-toner sensor connected
correctly?
11 Is the toner density low?
12 Are the image quality sensor and the
surface potential sensor normal?
13 Is the main charger dirty?
Replace the high-voltage transformer
with a new one and print out a test
chart.
If any abnormal image appears,
check the harness connection
between the LGC board and the
high-voltage transformer, power sup-
ply and stain on the main charger
wire.
Check the connection of the connec-
tor of the Auto-toner sensor.
Correct the toner density.
(Note 2: See 'Toner density correct-
ing method'.)
Check the performance of the image
quality sensor and the surface poten-
tial sensor. (See the trouble shooting
related with the image quality con-
trol.)
Clean or replace it.
5 - 144
Prescription
March 2005 © TOSHIBA TEC