2.13.5 Duplex blower mechanism
Duplex blower motor
In this machine, the paper floats on air to improve the
reliability of duplex paper feeding. Separation is easier
and damaging or soiling the leading edge of the paper is
prevented. Paper feed is also done by belt
transportation and suction from the duplex blower, so
there are two thin turbo fans with one blower motor.
A brushless dc servomotor with less friction, noise, and
electric noise is employed in the duplex blower to ensure
reliability and long life for the motor.
Vacuum solenoid
The solenoid is energized during duplex paper feeding.
The bottom sheet of the stack in the duplex tray is held
against the transport belts by the suction of the duplex
blower.
Air volume control for air knife
The motor rotation speed is controlled according to
paper size and the number of sheets stacked on the
duplex tray. So, the volume of air for the air knife
corresponds to the paper weight. It is always changed
during duplex paper feeding to apply the correct amount
of air to the leading edge of the paper in the duplex tray.
If the air volume is too high, the lowest sheet of the stack
cannot be transported by the belts. If it is too low, a
multifeeding may occur.
Air volume
L 4,500 rpm
M 6,000 rpm
H 7,000 rpm
Air knife solenoid
When the number of sheets in the duplex tray becomes
10 during duplex feeding, the air knife solenoid is
de-energized. (The blower rotation speed is not
changed.) This opens the air knife control shutter. The
shutter directs the air for the air knife to the exhaust,
preventing the air knife separation from affecting the
paper feed.
Due to this operation, the lowest sheet in the duplex tray
is held closely in contact with the transport belts by the
suction of the duplex blower. The lowest 10 sheets in the
duplex tray are mainly separated by the duplex feed and
reverse rollers rather than the air knife.
Air knife
control shutter
Exhaust
External
air
Air knife
solenoid
Turbo fan
Air
exhaust
External
airVacuum
solenoid
Air from duplex
transport belt
Vacuum shutter
Air knife solenoid ON
Waste air
Wind
volume: L, M,
Air knife SOL OFF
Air knife
SOL ON
Air knife
solenoid ON
Air knife solenoid OFF
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