Canon DADF-AG1, Service Manual

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Technology > Controls (DADF) > Document Detection > Initial Document Size Detection
Technology > Controls (DADF) > Document Detection > Initial Document Size Detection
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Initial Document Size Detection
The document length sensor 1 (SR7) and document length sensor 2 (SR10) detect the
longitudinal size of the document placed on the document tray, and the document width
volume (VR1) and A4R/LTRR identification sensor (SR8) detect the lateral size of the
document.
When a document is placed on the document tray, detection levers of the two document
length sensors move the light shielding plate to prevent light from passing through the photo
interrupter.
If the slide guide is adjusted to the document size, the resistance of the document width
volume mounted inside the document tray changes to detect the document size.
Document sizes are determined by the combination of the ON/OFF states of document length
sensors, the combination of ON/OFF states of document width volume, and the combination
of ON/OFF states of A4R/LTRR identification sensor.
SR10
SR7
VR1
SR8
F-2-10
The following table shows the relationship among length detection sensor signals,
document widths, and initial document sizes.
Document width detection Document length
detection
Detected size
Detection by
document width
volume (VR1) (mm)
A4R/LTRR
identification
sensor
(SR8)
Document
length
sensor 2
(SR10)
Document
length
sensor 1
(SR7)
AB/Inch
mixed
system
AB
system
Inch
system
W > 289
―
OFF OFF A4 A4 (LTR)
― ON ― A3 A3 (LDR)
― ― ON A3 A3 (LDR)
289 >/= W > 274 ― OFF OFF LTR (A4) LTR
―
ON
―
LDR (A3) LDR
― ― ON LDR (A3) LDR
274 >/= W > 247 ― OFF OFF B5 B5 (LTR)
― ON ― (B4) (B4) (LDR)
― ―
ON B4 B4 (LDR)
247 >/= W > 200 ON OFF OFF A5 A5 (STMT)
ON OFF A4R A4R (LTRR)
― ON (B4) (B4) (LGL)
OFF OFF OFF STMT (A5) STMT
ON OFF LTRR (A4R) LTRR
― ON LGL (B4) LGL
200 >/= W > 172 ― OFF OFF B6 B6 (STMT)
―
ON OFF B5R B5R (LTRR)
― ― ON (B4) (B4) (LGL)
172 >/= W ― OFF OFF A5R A5R (STMT)
― ON OFF (B5R) (B5R) (LTRR)
― ―
ON (B4) (B4) (LGL)
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