Canon imagePRESS C1 Service Manual - page 288
Chapter 5
5-9
F-5-17
To raise the accuracy of original size identification (as when the original is displaced while the ADF is closed), the machine makes use of the following 2 types of
mechanisms:
1. Presence/Absence of an Original at 2 Points (for each point of measurement)
For each point of measurement in main scanning direction, the machine checks the presence/absence of an original with reference to the CCD output at 2 points
near the point of measurement.
F-5-18
T-5-6
Note:
Changes in the Signal (from ADF open to close)
change: no
other: yes
The machine uses OR combinations for identification.
2.Priority on the Front Sensors
When checking the measurements for main scanning direction, if the absence of an original is indicated at the rear while the presence of an original is indicated at
the front, the machine will give priority to the indication at the front (i.e., presence of an original).
Result of measurement
Result of detection
1A
1B
no
no
original absent
yes
no
original present
no
yes
original present
yes
yes
original present
Point of original
detection 3
Point of original
detection 4
Point of original
detection 1
Print of original
detection 2
B5
B6
A5
A4
B5R
A4R
B4
A3
CCD original detection position
Point of original
detection 2
Point of original
detection 1
Point of original
detection 3
LTRR
STMT
LTR
LGL
279.4×431.8mm
(11"×17")
CCD original detection position
Original
sensor 3
AB-Configuration
Inch-configuration
STMTR
Original
sensor 1
Near 4 mm
Near 13 mm
1A:additional point
of detection
Original size
border line
Original size
border line
1B:conventional point
if detection