Media-size detection
The MFP has three media-size detection systems:
■ Cassette (tray 2) media-size detection
■ Media-length detection
■ Media-width detection
Cassette media-size detection
The media-size detection switch (SW102) has two functions: it detects the presence of the cassette,
and it detects the size of the media that is loaded in the cassette. This switch has upper, middle, and
lower components that act together to detect the cassette presence and the media size.
Table 5-3 Cassette media-size detection switch components
Cassette presence or
media size
Upper switch Middle switch Lower switch
No cassette Off Off Off
A4 Off Off On
LTR Off On Off
B5 Off On On
A5 On Off Off
EXE On Off On
LGL On On Off
UNV On On On
Media-length detection
The top-of-page sensor (PS103) determines the length of the media by measuring the time between
detecting the leading and trailing edges. If this size does not match the size that SW102 detects or
the size that the formatter specifies, the dc controller sends a signal to the formatter. If the media
size that PS103 measures is shorter than the media size that the user selected, the formatter masks
part of the image to prevent extra toner from transferring from the photosensitive drum to the transfer-
charging roller.
Media-width detection
Two media-width sensors (PS106 and PS112) act together to determine if the media is narrower
than expected or is skewed. If either of these conditions is detected, the dc controller adjusts the
fuser temperature to prevent overheating. PS106 detects media that is narrower than 122 mm
(4.8 inches). PS112 detects media that is narrower than 188 mm (7.4 inches).
Cassette pickup operation
The dc controller turns on the cassette pickup solenoid (SL101) and the main motor (M101) drives
the cassette pickup roller and the cassette pickup cam. The cam causes the arm that is attached to
108 5 Theory of operation
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