Fusing Bias; Fusing Unit Scs - Ricoh B156 Service Manual

[A]: High voltage supply
[B]: Terminal
[C]: Fusing belt
[D]: Hot roller
[E]: Heating roller
[F]: Pressure roller
[G]: Oiling roller

Fusing Bias

The high voltage supply [A] provides the fusing bias in a new fusing unit until 2K
prints are made. The fusing bias is a negative voltage that quenches static
electricity created on the belt [C] and rollers [D]∼[F] in a new fusing unit by the
paper. This prevents the belt and rollers from attracting dust and dirt, which can
cause offset image in black areas and/or white spots in half tone images because
of toner attracted to the fusing belt.
After 2K prints, the static electricity is not very high. If the bias is applied to the
oiling roller, this can attract dust and dirt to the oil supply felt area. Because of this,
the bias is turned off after 2K prints.
With SP2-503, you can select the status of bias control (Always off, Always on, or
Auto [turns off after 2k prints]). After a new fusing unit is installed, fusing bias must
be applied during the first 2K prints. To do this, you must reset the PM counter of
the fusing unit with SP7-804-7, and fusing bias control will automatically switch on
(the machine uses the Auto setting).
SP2-501 shows the current status of fusing bias control. The setting is changed
from 1 (ON) to 0 (OFF) when 2K prints from the new unit are made or when SC420
is detected. At this time, the fusing bias is stopped.

Fusing Unit SCs

If a thermistor/thermostat problem occurs, a fusing unit SC may be displayed on
the operation panel. Fusing unit SCs disable the machine (
fusing unit SCs, use SP5-810 (
B156/B220
CÓPIA NÃO CONTROLADA
[C]
[D]
[E]
[F]
5.1.2).
6-68
CÓPIA NÃO CONTROLADA
IMAGE FUSING AND PAPER EXIT
[B]
[G]
4.1.1). To reset
[A]
B156D053.WMF
SM