Ricoh B082 Service Manual page 914

Rev. 09/2003
6.9.4 DEVELOPMENT BIAS
Mechanism
In a negative-positive development
system, black areas of the latent image
are at a low negative charge (about –
150 V) and white areas are at a high
negative charge (about –950 V).
To attract negatively charged toner to
the black areas of the latent image on
the drum, the high voltage supply board
[A] applies a bias of –600 volts to the
development roller throughout the image
development process. The bias is
applied to the development roller shaft
[B] through the bias terminal spring [C]
and bias terminal [D].
The development bias voltage (-600 V) can be adjusted with SP2-201
(Development Bias).
Correction for paper width and thickness (by-pass tray only)
The by-pass tray can be used for non-standard paper narrow than sizes accepted
by the paper trays. Thicker paper, OHP sheets, etc. can also be loaded in the by-
pass tray but adjustments must be performed with the SP modes listed below in
order to avoid jams and misfeeds.
SP Mode
⇒
SP2-201-1 Development Bias
SP2-309-1 Paper Lower Width [a]
SP2-309-2 Paper Upper Width [b]
⇒
SP2-914-3
Process Control Setting (Bγ)
SP2-914-4
Process Control Setting (Bδ)
The way that these SP modes are used is shown below.
SP22011 + SP29143
Default: -510 + 200 V
0 mm
SP2-201-1 + SP2-914-3
SP22011 + SP29143
⇒
Default: -600+250 V
Default: -510 + 200 V
For example, with the default settings, if the paper width fed from the by-pass tray
is 200 mm, the development bias voltage will be –600 + 50 V.
SM
SP Name
SP 2-309-1
Default: 150 mm
Voltage:
SP22011 + SP29144
SP2-201-1 + SP2-914-4
Default: -510 + 50 V Default: -600+50 V
[D]
[B]
Width 216 -297 mm (Default: -510 V)
Width limit: (Default: 150 mm)
Width limit: (Default: 216 mm)
Adjust 10V/step (Default: 200 V)
Adjust 10V/step (Default: 50V)
SP 2-309-2
Default: 216 mm
Voltage: Voltage:
SP2-201-1
SP22011
Default: -600 V
Default: -510 V
6-61
DEVELOPMENT
[A]
[C]
B004D404.WMF
297 mm
B004D508.WMF
B079/B082