Toshiba e-STUDIO 200L Service Manual page 109

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).
Magnetic roller
Fig. 3-8
The (-) potential of
the photoconductive
drum is higher than
the developer bias.
The (-) potential of
the photoconductive
drum is lower than
the developer bias.
- 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).
June 2004 © TOSHIBA TEC
Drum
Magnetic roller
Bias voltage
- 357 VDC
Photocon-
ductive
drum
White background
White background
- 495V
- 357V
- 300V
- 200V
- 100V
0
Fig. 3-10
3 - 5
Magnet
Toner
Carrier ( always attracted
onto the magnet )
Toner
Toner
Photoconductive layer
Aluminum base
Fig. 3-9
Solid
Halftone
Image not developed
Bias
potential
Image developed by
toner
e-STUDIO200L/202L/230/232/280/282 COPY PROCESS
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