e-STUDIO160/200/250 COPYING PROCESS 3 - 4 December 2002 TOSHIBA TEC
(5) Development
• “Developing” is the process of converting the
electrostatic latent image to an image vis-
ible to the human eye.
The developing agent is fed to the surface of the photosensitive drum by the magnetic rollers, and
impressed on the rollers. Toner in the developer agent attaches to areas on the photosensitive drum
having a potential lower than the developer bias (reverse developing method).
• Switching of developing bias polarity
Fogging is reduced by switching the bias of negative voltage charged areas to positive
polarity (approx. +150V).
• About Developing Agent
Toner and carrier are mixed. The toner is
charged to minus polarity, and the carrier is
charged to plus polarity by friction caused
by stirring.
Toner: Comprises plastic and Magnetite.
Carrier: Ferrite
0
100V
200V
300V
460V
or
430V
600V
Intermediate tones
Black solidWhite background
White background
Image is not developed
by bias potential.
Bias
voltage
When the potential
of the photosensitive
drum is higher than the
developer bias:
When the
potential
of the photosensitive
drum is lower than the
developer bias:
03009-a
Magnetite
(40 ~ 65%)
Resin
(35 ~ 60 %)
[Toner] [Carrier]
Ferrite
5 ~ 20 µm
Approx. 60 µm
Image is developed by
toner.
Drum
Sleeve roller
03008
03009
Magnet
Toner
Carrier
(Always attracted
on to the magnet)
Bias voltage
-460V or -430V
Sleeve
Fig. 3-2-7
Fig. 3-2-9Fig. 3-2-8
Fig. 3-2-10
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