Toshiba e-studio 202L, Service Manual, Page: 109 / 354

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June 2004 © TOSHIBA TEC e-STUDIO200L/202L/230/232/280/282 COPY PROCESS
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5) Development
Development is the process of making the electrostatic latent images visible to the eye (visible
images).
Developer material is supplied to the photoconductive drum surface by the magnetic roller.
The toner in the developer material adheres to the areas on the drum surface where the potential is
lower than the developer bias which is applied to the magnetic roller (reverse development method).
Fig. 3-10
- Switching of developer bias polarity
With the area which has no negative charge, background fogging is decreased by switching the
bias to the positive polarity (approx. +150 V).
- Charging AC bias
To obtain the stable development characteristics, AC bias (approx. 1,100 V) is charged to the
development bias (DC bias).
Fig. 3-8
Fig. 3-9
Drum
Magnetic roller
Photoconductive layer
Magnet
Magnetic roller
Photocon-
ductive
drum
Aluminum base
Toner
Carrier (always attracted
onto the magnet)
Toner
Bias voltage
- 357 VDC
Toner
The (-) potential of
the photoconductive
drum is higher than
the developer bias.
The (-) potential of
the photoconductive
drum is lower than
the developer bias.
0
- 100V
- 200V
- 300V
White background Halftone Solid
White background
Image not developed
Bias
potential
- 495V
- 357V
Image developed by
toner