Canon Color Image Reader - L1 Service Manual page 21

2
Technology
b. Priority on the front original presence
As a result of main scanning direction measurement, if the original absence is detected at
the rear while the original presence is detected at the front, a priority is given to the result of
original presence at the front.
Point of detection 1
Point of detection 2
Point of detection 3
Point of detection 4
B5
Point of detection 5
Scanner unit
original detection position
Original detection position Result Identifi ed size
1 Y
2 -
3 -
4 Y
5 -
Judgment
* Signal change with DADF Open to Close
Change: -
Others: Y
2
Technology
Original
size
sensor1
Y
Y
Y
Y
-
B5
Detection operation
Following is the overview of operation for original size detection (AB type).
1) Wait status
Scanner unit: shading position
LED lamp unit: OFF
Original size sensor: OFF
DADF
DADF open/closed sensor 2
DADF open/closed sensor 1
Reader unit
2) DADF opened (The angle of DADF is 25 degree or more).
Scanner unit: It moves to the original detection position (20mm from the original push-on
position)
LED lamp unit: OFF
Original size sensor: OFF
Scanner unit
Original size
sensor 1
Point of detection 1
Point of detection 2
Point of detection 3
Point of detection 4 Copyboard
Point of detection 5 glass
Original detection position
2-10
2-10