Near End/End Detection - Gestetner B147 Service Manual

2.5 NEAR END/END DETECTION

This tray holds two stacks of paper, so the machine needs to monitor the status of
both these stacks. There are seven sensors to do this.
In the right tray (paper feed side), three height sensors ([E] in the diagram on the
previous page) measure the height of the stack, and an end sensor detects when
all the paper is used up. As the amount of paper remaining in the tray decreases,
the base plate rises and the actuator activates the paper height sensors. When
paper runs out in the right tray, the stack in the left tray is moved across to the right
tray.
There are also two height sensors ([F] in the diagram on the previous page) and an
end sensor in the left tray (paper storage side) ([G] in the diagram on the previous
page). When there is no paper in both trays, paper end is detected.
The machine determines the amount of remaining paper based on the sensor
outputs, as shown in the following table.
Paper Height Sensor 1
Paper Height Sensor 2
Paper Height Sensor 3
Right Tray Paper End Sensor
Paper Height Sensor 4
Paper Height Sensor 5
Left Tray Paper End Sensor
Paper Height Sensor 1
Paper Height Sensor 2
Paper Height Sensor 3
Right Tray Paper End Sensor
Paper Height Sensor 4
Paper Height Sensor 5
Left Tray Paper End Sensor
Right tray paper end sensor: " = Low (no paper), $ = High (paper present)
Other sensors: " = Low (paper present), $ = High (no paper)
The following diagram is the sensor layout, as viewed from the front.
SM
100% 75%
" " "
" " "
" " $
$ $ $
" " "
" $ "
" " "
Amount of paper
25%
$ " "
–
" $
– –
$
$ $ $
" $ $
$ $ $
" " "
Paper Storage Side Paper Feed Side
Paper Height
Sensor 1
Paper Height
Paper Height
Sensor 5
Sensor2
Paper Height
Paper Height
Sensor 4
Sensor 3
Paper End
Sensor 2
15
NEAR END/END DETECTION
Amount of paper
50%
" " " $
–
" " $
– –
" "
$ $ $ $
$ $ " "
$ $ " "
" $ " "
Near-end
" " $ $
– –
" $
– – –
$
$ $ $ $
$ $ $ $
$ $ $ $
$ $ " $
Paper End
Sensor 1
B600D112.WMF
" "
" $
–
$
$ $
" "
$ $
" "
End
–
–
–
"
$
$
$
B600