Ricoh A028 Service Training Manual page 146

ADF
2.14.5 Original separation and feed
Original leading edge separation
Air from the ADF blower is blown through six holes in the
air knife casing to the center of the original.
The blower keeps blowing air on the original tray from
the beginning to the end of the original feeding to
prevent double feeding of originals.
Original feed
After the originals are separated by the ADF blower, the
shutter solenoid mounted on the ADF blower is
energized by a paper feed signal from the main control
board. The bottom sheet is held against the transport
belts by the suction of the ADF blower.
Next, through the timing belt and feed magnetic clutch,
the original feed motor drives the feed rollers and
transport belts. The belts transport the original to the
feed rollers.
Blower
The air suction and air knife separation are provided by
two turbine fans on one blower.
A brushless dc servomotor with reduced wear, noise
and electrical noise is used in the ADF blower to ensure
long life and high reliability.
Shutter solenoid
The shutter solenoid controls air suction to hold the
lowest original of the stack against the transport belts.
When this solenoid is OFF, the vacuum shutter is
opened and the original is not affected by suction.
In the stack mode (the ADF mode), the originals may be
damaged by the air suction if the originals stay in the
same place for a long period. To prevent this, in the
stack mode, if the selected copy number for an original
goes over 9, the solenoid is automatically turned OFF.
The solenoid is again turned ON for the last 6 copies.
Air knife casing
Original feed roller
Air inlet
To air knife
Air exhaust
Air suction
2-110
1 July 1994
ADF blower
Shutter solenoid
Original feed
magnetic clutch
Original feed
motor
Joint gear
ADF blower
Shutter solenoid
Vacuum shutter
Suction when solenoid ON