2.1.3 Tray up/down and paper volume detection
Paper volume detection
Rotation of the tray motor (reversible motor) on the rear
of the tray, raises the paper tray lift rods fastened to the
tray drive wires as shown in the figure.
The tray motor is equipped with a pulse generator disk
and paper volume sensor. The paper feed control board
counts the number of pulses from the tray starts moving
up until the upper limit sensor turns on. The volume of
paper remaining is indicated.
The number of pulses continues to be added as the tray
motor rotates during copying. When the volume of paper
becomes small, the paper volume display is changed
accordingly.
When the paper volume display bar shows 1,
approximately 200 sheets of paper remain. At the
guidance display, paper near end is indicated (displayed
in white letters). However, paper can still feed.
Tray raising
When the lift rods are raised, the paper is also raised.
The upper surface of the paper contacts the pick-up
roller and raises it a little. Next, the actuator enters the
upper limit sensor. The tray motor then turns off and the
paper stops raising.
When copies are made, the upper surface of the paper
lowers. The sensor actuator gradually lowers and
releases the upper limit sensor. The tray motor then
turns on again, and the paper is raised.
Tray lowering
When you press the tray lowering key, the tray motor
reverses and lowers the paper tray lift rods.
When the lower limit sensor is activated by the actuator
on the lift rod, (this is the lower limit position,) the tray
motor stops. To improve performance, the tray motor
rotates at a higher speed when lowering than when
raising.
Rear tray
drive wire
Front tray
drive wire
Lower limit sensor
actuator
Paper volume sensor
Lower limit
sensorTray motor
Pulse
generator disk
Paper tray
lift rod
Reverse roller
Paper feed roller
Pick-up roller
Upper limit
sensor actuator
Upper limit sensor
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