Initial Document Size Detection - Canon H1 Service Manual

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Technology > Controls (DADF) > Document Detection > Initial Document Size Detection

■ 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
SR8
2 Technology > Controls (DADF) > Document Detection > Initial Document Size Detection
SR7
VR1
F-2-33
The following table shows the relationship among length detection sensor signals,
document widths, and initial document sizes.
Document width detection Document length
detection
Detection by A4R/LTRR Document
document width identification length
volume (VR1) (mm) sensor sensor 2
(SR8) (SR10)
―
W > 289 OFF
― ON
― ―
289 >/= W > 274 ― OFF
―
ON
― ―
274 >/= W > 247 ― OFF
― ON
― ―
247 >/= W > 200 ON OFF
ON
―
OFF OFF
ON
―
200 >/= W > 172 ― OFF
― ON
― ―
―
172 >/= W OFF
― ON
― ―
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Detected size
Document AB/Inch AB Inch
length mixed system system
sensor 1 system
(SR7)
OFF A4 A4 (LTR)
― A3 A3 (LDR)
ON A3 A3 (LDR)
OFF LTR (A4) LTR
―
LDR (A3) LDR
ON LDR (A3) LDR
OFF B5 B5 (LTR)
― (B4) (B4) (LDR)
ON B4 B4 (LDR)
OFF A5 A5 (STMT)
OFF A4R A4R (LTRR)
ON (B4) (B4) (LGL)
OFF STMT (A5) STMT
OFF LTRR (A4R) LTRR
ON LGL (B4) LGL
OFF B6 B6 (STMT)
OFF B5R B5R (LTRR)
ON (B4) (B4) (LGL)
OFF A5R A5R (STMT)
OFF (B5R) (B5R) (LTRR)
ON (B4) (B4) (LGL)
T-2-13
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