Toshiba e-STUDIO520 Service Manual page 82

Note:
If the developer material is used for a long time
(beyond its normal life span), the toner is caked
onto the carrier.
p
The carrier's (charging) performance is low-
ered.
Symptom:
1) Image density is decreased.
2) Toner scattering occurs.
3) Background fogging occurs.
Solution:
Replace new developer material.
• Magnetic roller
- Magnetic brush development -
The south and north poles are arranged inside the magnetic rollers, as shown in the following figure.
The developer material forms a brush-like fluff which contacts the photoconductive drum surface
p
This is caused by the lines of magnetic force between the south and north poles.
• Additional Explanation
The life of the toner cartridge (number of copies) varies depending on the following conditions.
1) Coverage of originals (printing image ratio of the original size) and density of original background
2) Size and density of originals
3) The existence of solid black when making copies (when a book is copied and the original cover is
partially open)
4) Temperature and humidity in the room when making copies
5) Copy density and image quality mode
As indicated in the figure below, the life of the toner cartridge varies depending on the copy mode
and coverage of originals
e-STUDIO520/600/720/850 COPY PROCESS
Photoconductive
drum
Fig.3-13
3 - 6
Toner
No frictional electrification
on the area where the toner
is caked on.
Fig.3-12
Lines of
magnetic force
N
Magnetic roller
Carrier
March 2005 © TOSHIBA TEC