Functions - Toshiba e-STUDIO556 Service Manual

3.14.2

Functions

(1) Transfer belt unit
The transfer belt unit is a main unit of the transfer section. This unit is divided into 2 parts; the belt
support/power supply section which supports and rotates the belt and supplies the power to the
belt, and the cleaning mechanism section which scrapes off the toner adhered on the belt
surface.
The transfer belt motor (M14) drives the transfer belt unit.
The drive from the transfer belt motor (M14) is transmitted to the drive gear and drive roller
through the timing belt and relay gears. The drive is transmitted to the transfer/transport unit with
a gear having a planetary joint.
(2) Transfer belt support/power supply section
The transfer belt is supported by 3 rollers; transfer belt drive roller, follower roller and power
supply roller. A voltage, whose polarity is reverse to that of the toner on the photoconductive
drum, is applied on the power supply roller. The current flowing to the transfer belt is controlled at
a constant current of 70 µA (85 µA: e-STUDIO756/856). (The voltage is normally between +2 kV
and +5 kV, while the applied voltage changes due to this constant-current control.) A voltage of
+510 V is applied on the follower roller by a varistor. A high-voltage probe is required for this
measurement. Do not use a digital voltmeter for your safety.
(3) Transfer belt
The transfer belt is a high-precision flat rubber belt with coating, holding electrical resistance,
which electrostatically attracts the paper (toner).
(4) Transfer belt cleaning mechanism
The transfer belt cleaning mechanism section scrapes off the residual toner or paper dusts on
the transfer belt surface with the transfer belt cleaning blade and transfer belt cleaning brush,
and also transports the used toner with the recovery auger.
(5) Transfer belt cleaning blade
The cleaning blade removes paper dusts and foreign objects left on the transfer belt surface after
the separation of the paper.
(6) Transfer belt cleaning brush
The cleaning brush is a conductive part to clean the toner electrostatically, and the voltage
whose polarity is reverse to that of toner is applied on it. The current flowing to the cleaning brush
is controlled at a constant current of 5 µA. (The voltage is normally between +100V and +500V,
while the applied voltage changes due to this constant-current control.) A high-voltage probe is
required for this measurement. Do not use a digital voltmeter for your safety.
(7) Recovery auger
The recovery auger transports the residual toner scraped off with the transfer belt cleaning blade
and transfer belt cleaning brush to the used toner transport auger section.
(8) Transport guide
The transport guide leads the electrostatically attracted paper to the fuser unit. The guide is
made of a material which prevents a frictional charge caused by the paper.
e-STUDIO556/656/756/856(Ver03)
OUTLINE OF THE MACHINE
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