Canon Color Image Reader - L1 Service Manual page 20

2
Technology
Following is the combination of detection result and original size.
A/B: Original presence/absence detection result of 2 points (Refer to [2 point original detec-
tion at each detection position].).
Y: Output level has no change (refer to [Detection operation]).
-: Output level has change (refer to [Detection operation]).
Scanner unit detection position
Original size 1 2
A B A B A
A3 Y Y Y Y Y
B4 Y Y Y Y Y
A4R Y Y Y Y Y
A4 Y Y Y Y Y
B5 Y Y Y Y Y
B5R Y Y Y Y -
A5 Y Y Y Y Y
B6 Y Y Y Y -
A5R Y Y - - -
None - - - - -
Scanner unit detection position
Original size 1 2
A B A B A
11" x 17" Y Y Y Y Y
LGL Y Y Y Y -
LTRR Y Y Y Y -
LTR Y Y Y Y Y
STMTR Y Y - - -
STMT Y Y Y Y -
Absent - - - - -
To keep the high accuracy detection even though an original moves when the DADF is
closed, this machine has 2 types of controls.
2
Technology
3 4 5 Original size sensor 1
B A B A B
Y Y Y Y Y Y
Y Y Y - - Y
Y - - - - Y
Y Y Y Y Y -
Y Y Y - - -
- - - - - Y
Y - - - - -
- - - - - -
- - - - - -
- - - - - -
3 Original size sensor 2
B
Y Y
- Y
- -
Y -
- -
- -
- -
a. 2 point original detection at each detection position
In main scanning direction, the machine determines whether the original is present or not
from the 2 points of CMOS output near the original detection position.
Original size
border line
Near 13 mm
1A: additional point
Near 4 mm
1B: conventional point
Original size
border line
Result
Judgment
A B
Y Y Present
Y - Present
- Y Present
- - Absent
* Signal change with DADF Open to Close
Changed: -
Others: Y
The machine uses OR combinations of 2 points for identifi cation.
of detection
if detection
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2-9