Canon imageRUNNER ADVANCE 4551i Service Manual page 86

Document width is detected by the Document width sensor 1/2/3 (SR13/SR14/SR15) which performs by light prevention plate
connected with the Slide guide adjustment.
Document sizes are determined by combination of ON/OFF states of these sensors.
The Document length sensor 1 (SR7) is a Reflection Sensor which is available to detect the length of a document in case that
the curled paper is placed on the document pickup tray.
The following table shows the relationship among length detection sensor signals, document widths, and initial document sizes.
Document width detection
Width (mm) Document
width sensor
1 (SR13)
143.9 or less OFF
More than OFF
143.9 and
165.0 or less
More than OFF
165.0 and
196.0 or less
More than ON
196.0 and
213.9 or less
More than ON
213.9 and
236.5 or less
More than ON
236.5 and
263.5 or less
SR15
Document Document
width sensor width sensor
2 Document 3 (SR15)
(SR14)
OFF OFF
ON ON
OFF ON
OFF ON
ON ON
OFF OFF
SR8
SR14
Document length detec-
tion
Document Document
length sensor length sen-
1 (SR7) sor 2 (SR8)
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
OFF OFF
ON ON
OFF ON
ON OFF
73
SR7
SR13
Detected size
AB INCH AB/INCH
- - STMTR
- - STMTR
- - STMTR
- STMTR STMTR
- - A5R
- - A5R
- - A5R
A5R - A5R
- - B5R
- - B5R
B5R - B5R
B6 - B6
- - A4R
- - A4R
A4R - A4R
A5 - A5
- LGL LGL
- - LGL
- LTRR LTRR
- STMT STMT
B4 - B4
- - B4
- - B4
2. Technology
AB/K
A5R
A5R
A5R
A5R
A5R
A5R
A5R
A5R
B5R
B5R
B5R
B6
A4R
A4R
A4R
A5
B4
B4
B4
B5
B4
B4
B4