Toshiba E-STUDIO520, Service Manual, Page: 454 / 592

e-STUDIO520/600/720/850 TROUBLESHOOTING March 2005 © TOSHIBA TEC
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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.
Main charger output 8 Is the setting value proper?
Is the main charger output normal? 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.
Developer unit 9 Is the contact between the drum and
developer material normal? 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.
Developer bias output 10 Is the setting value proper?
Is the developer bias output normal? If the setting value is out of specifica-
tion, adjust it.
If the output is not normal, check the
circuits. (Note 1)
Increasing toner density 11 Is the Auto-toner sensor connected
correctly? Check the connection of the connec-
tor of the Auto-toner sensor.
12 Is the toner density high? Adjust the toner density.
(Note 2: See the toner density cor-
recting method.)
Image quality sensor/
Surface potential sensor 13 Are the image quality sensor and the
surface potential sensor normal? Check the performance of the image
quality sensor and the surface poten-
tial sensor. (See the troubleshooting
related with the image quality con-
trol.)
Drum cleaning blade 14 Is the drum cleaned properly? (See the troubleshooting for the poor
cleaning.)
Defective area Step Check items Prescription