Original Size Detection By Original Size Detection Sensors - Canon imageRUNNER 1750 Series Service Manual

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Technical Explanation > Original Exposure and Feed System > Controls > Original Size Detection by Original Size Detection Sensors

■ Original Size Detection by Original Size Detection Sensors

● Overview
Presence or absence of an original on the copyboard glass is detected as follows according
to the combination of the output levels of reflective photo sensors:
• Absence of original: The level of the reflected light from the reflective photo sensor, which
is detected when the ADF is open, changes when the ADF is closed.
• Presence of original: The level of the reflected light from the reflective photo sensor, which
is detected when the ADF is open, does not change when the ADF is closed.
Sensor mounting locations are shown below.
• Main and sub scanning direction: Reflective photo sensor (2 locations)
Upper left corner
of original
STMTR
Main scanning
direction
A5R
A4R
LTRR/LGL
Original size detection sensor 1
(PS22)
2 Technical Explanation > Original Exposure and Feed System > Controls > Original Size Detection by Original Size Detection Sensors
Sub scanning direction
Size plate
Original size detection sensor 2
(PS21)
● Outline of Original Size Detection
When the ADF is closed at 18 degrees, the ADF open/closed detection sensor (PS23) turns
on. The output levels of the original size detection sensor 1 (PS22) and original size detection
sensor 2 (PS21) are read for 2 seconds after the ADF open/closed detection sensor (PS23)
turns on or until the Start key is pressed. If the output levels change, the machine judges that
no original is present. If they do not change, the machine judges that an original is present.
1) ADF opens (ADF open/closed detection sensor (PS23): OFF)
Original size detection sensor 1 (PS22)/Original size detection sensor 2 (PS21): OFF
2) ADF is closed to an angle of approximate 18 degrees. (ADF open/closed detection
sensor (PS23): ON)
Original size detection sensor 1 (PS22)/Original size detection sensor 2 (PS21): ON or
OFF
F-2-23
PS23: ON
Original size detection sensor 1
(PS22)
ADF
PS23: OFF
Original
F-2-24
ADF
Approx. 18°
Original
Original size detection sensor 2
(PS21)
2-14
F-2-25
2-14