Sharp AR-280 Service Manual page 188

Document sizes and sensor states
Document size and
set direction
INCH-1 B5R
INV (5.5 ´ 8.5)
LTR (8.5 ´ 11R)
LGR (8.5 ´ 14R)
B5
B4R
LT (8.5 ´ 11)
WLTR (11 ´ 17R)
A4
A3R
INCH-2 B5R
INV (5.5 ´ 8.5)
LTR (8.5 ´ 11R)
L4R (8.5 ´ 13R)
B5
B4R
LT (8.5 ´ 11)
WLTR (11 ´ 17R)
A4
A3R
SEEG SUK B5R
LGR (8.5 ´ 14R)
Japan
A5
A4R
B5
B4R
LT (8.5 ´ 11)
WLTR (11 ´ 17R)
A4
A3R
SCA B5R
F4R (8.5 ´ 13R)
A5
A4R
B5
B4R
LT (8.5 ´ 11)
WLTR (11 ´ 17R)
A4
A3R
2) Document size detection by the post-separation
sensor (SPS)
This detection method supplements an incompleteness of document
size detection on the document set tray when documents of different
sizes are set together. Therefore, the detection result of this method
has priority over that of the document set tray.
7/13/2000
TRVR
TRS-S TRS-L
Sensor states
(Detection level, or ON: , OFF:
TRVR TRS-S TRS-L
1
2
2
2
3
3
4
4
5
5
1
2
2
2
3
3
4
4
5
5
1
2
2
2
3
3
4
4
5
5
1
2
2
2
3
3
4
4
5
5
The document length is detected by counting the number of pulses of
the paper feed motor (AMOT) and the transport motor (FMOT) during
the time interval from when the paper feed motor (AMOT) starts
rotation, that is, the resist roller starts rotation, and a document is fed
from the paper feed section to the paper transport section to when
the post-separation sensor (SPS) detects the rear edge of the docu-
ment. With the detected document length and the document width
detected by the size volume (TRVR), the document size is identified.
Resist roller
(B) Document rear edge
Resist roller
The number of pulses of the paper feed motor (AMOT) and the
transport motor (FMOT) during the time interval between (A) and (B)
is counted.
3) Document size detection by the read sensor (RDS)
This detection method supplements an incompleteness of document
size detection on the document set tray when documents of same
width but different length are set together (LTR/LGR judgement) or
when document of a larger size than LT whose rear edge is not
detected by the post-separation sensor (SPS) are set. Therefore, the
detection result of this method has priority over that of the document
size detection by the post-separation sensor.
When the transport motor (FOMT) rotates in the normal direction, the
read roller start rotation and the document is fed from the paper feed
section to the paper transport section. At that time, The number of
pulses of the transport motor (FMOT) is counted while the read sen-
sor reads the document from the lead edge to the rear edge, and the
document length is detected from the count.
With the detected document length and the document width detected
by the size volume (TRVR), the document size is identified.
Read roller
(A) Document lead edge
Read sensor
Read roller
(B) Document rear edge
Read sensor
The number of pulses of the transport motor (FOMT) between (A)
and (B).
10 – 8
(A)
Separation roller
Post-separation sensor