Canon imageRUNNER 2545 Series Service Manual page 37

2
Technology > Original Exposure System > Controls > Detecting the Size of Originals
● Detection Operation Overview
1) Standby state (The following is in case that the AB type, A4R size is set.)
CCD unit: shading position
LED: OFF
Original sensor: OFF
CCD unit
ADF
Reader unit
CCD original detection position
2) ADF opened
CCD unit: moves to original detection position
LED: OFF
Original sensor: OFF
(External
light)
3) ADF closed
CCD unit: in original detection position
LED: OFF to ON
Original sensor: in original detection operation
- With the ADF angle at 25 deg or less, the external light is blocked at the original width
area. Then, the machine determines that the original is absent at the points that the
external light is detected (external light search operation). When the original mount sensor
(rear) detects [close], original size detection is started. In this case, B5/B4/A4/A3 size is
eliminated at this point.
- After external light search, LED is turned ON at main scanning side and the CCD checks
the reflection light (4 points). For sub scanning direction, original sensor detects the size.
（External
light）
2 Technology > Original Exposure System > Controls > Detecting the Size of Originals
Original sensor
Position of detection 1
Position of detection 2
Position of detection 3
Position of detection 4
Copyboard glass
F-2-17
F-2-18
F-2-19
25°
4) ADF fully closed (5 deg or less)
CCD unit: in original detection position
LED: ON
Original sensor: in original detection operation
- For 2 sec from the original mount sensor (front) detected [close], this monitors the
changes of output level of each sensor. The machine determines that the original is
present in the position where the level is not changed.
The machine identifies the original size by the combination of level changes at 5 points (in
case of AB type size).
5°
5) Standby status (waiting for start key)
CCD unit: in original detection position
LED: OFF
Original sensor: OFF
ABtype
CCD detection position
Original
Original
1 2 3 4
size
sensor 0
A B A B A B A B
A3
B4
A4R
A4
B5
B5R
A5
B6
Absent
2-11
F-2-20
F-2-21
F-2-22
Inch type
CCD detection position
Original Original
1 2 3
size sensor 1
A B A B A B
11"×17"
LGL
LTRR
LTR
STMTR
STMT
Absent
：No change ：Changed
F-2-23
2-11