Ricoh A028 Service Training Manual page 42

Paper Feed
2.1.5 Paper feed and separation mechanism
Unit configuration
This equipment has four paper feed units, including an
optional LCT.
Paper feed units 1, 2, and 3, and the LCT, are as shown
in the figure. (Units 1 and 2 are the same. The exit paper
guide plate is different for the LCT, trays 1 and 2, and
tray 3.)
An FRR system, using a torque limiter on the reverse
roller shaft, is employed.
Paper feed/separation mechanism
Standby operation
When the main motor is turning, the grip roller rotates in
the direction of the arrow. The reverse roller shaft
always rotates opposite to the direction of paper feed.
The reverse roller has a torque limiter built in. The
reverse roller has a tendency to rotate with the torque of
the torque limiter, but it is stabilized by friction of contact
between the reverse roller and the paper feed roller.
Paper feed operation
When the paper feed motor is turned ON by a paper
feed signal from the main control board, the gear starts
to rotate the pick-up roller in the direction of the arrows.
The internal, one-way clutch starts the rotation of the
paper feed roller.
This action feeds paper. The first paper feed sensor
detects the paper and turns ON the pick-up solenoid.
The pick-up roller raises and the load on the paper is
reduced.
When the paper is fed, the second paper feed sensor
detects the paper, and the paper feed motor is turned
OFF once. The second time the paper feed motor is
turned ON, the grip roller catches the paper and feeds
the paper to the registration roller unit.
Sensor operation
1st paper feed sensor
2nd paper feed sensor
The time from when the paper feed motor is turned ON
the second time to when the registration sensor comes
ON is measured, and time variations are fed back to the
second paper feed motor ON timing. For more details,
see the timing chart section.
Jam detection
Pick-up solenoid ON
Paper feed motor OFF
Jam detection
Pick-up solenoid
Paper feed roller
Pressure spring
Grip roller
2nd paper feed sensor
Grip roller
Paper feed
roller (one-way
clutch, built in)
Reverse roller
2nd paper
feed sensor
Paper
feed roller
1st paper feed sensor
2-6
Paper feed motor
Upper limit sensor
Pick-up roller
Reverse roller
1st paper feed sensor
Paper feed sensor board
Paper feed motor
Reverse roller shaft
Pick-up roller
Pick-up roller
1 July 1994