Intermec EasyCoder 501 XP & 601 XP – Service Manual
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Chapter 8 Print Unit
8.6 Label Stop Sensor
Description (EasyCoder 501 XP and 601 XP)
The label stop sensor (LSS) is used to control the media feed and
consists of a sliding carriage on which two photoelectrical sensors
are fi tted. Both sensors are identical and contain one light-emitting
diode and one light-sensitive receiver. The distance from the light
path between the two parts of the LSS to the dot line on the print-
head is 46.3 mm (1.82 inches.) The sensors can be moved up to
50 mm (1.97 inches) out from the inner edge of the media path by
means of a screw protruding through the lower outer gable of the
print unit. The label stop sensor is hidden inside the print mecha-
nism and covered by two black plastic guide plates, which can be
removed for cleaning.
Working Principles (EasyCoder 501 XP and 601 XP)
The label stop sensor serves a number of purposes, depending on
how the printer is set up in regard of media type:
Label (w gaps)
A beam of light is emitted from the upper sensor and received by
the lower sensor. The fi rmware detects the
front
of each label, taht
is when the light is completely interrupted by the opaque label, as
opposed to the semi-transparent liner in the gaps between labels.
If no label has been detected during a media feed corresponding
to more than 150% of the set label length (Setup\Media\Media
Size\Length), a “next-label-not-found” condition is assumed. If a
renewed print operation gives the same result, an “out-of-paper”
condition is assumed.
Ticket (w mark)
A beams of light is emitted from the lower sensor
1
. The beam can
either be refl ected back to the same sensor by the white media, or
be absorbed by a black mark. The fi rmware detects when the front
edge of a black mark passes the sensor, that is when light starts
to be absorbed. If no mark has been detected during a media feed
corresponding to more than 150% of the set ticket length (Setup\
Media\Media Size\Length), a “next-label-not-found” condition is
assumed. If a renewed print operation gives the same result, an
“out-of-paper” condition is assumed.
Ticket (w gaps)
The light is emitted from the upper sensor and received by the
lower one. The light will either pass uninterrupted through a detec-
tion gap in the media or be blocked by the non-transparent ticket.
The fi rmware detects the rear edges of detection gaps, that is when
the light starts being interrupted. If no ticket has been detected
during a paper feed corresponding to more than 150% of the set
ticket length (Setup\Media\Media Size\Length), a “next-label-not-
found” condition is assumed. If a renewed print operation gives the
same result, an “out-of-paper” condition is assumed.
1
/. For detection of black marks on the
top of the media, the cables from the
two sensors could be switched on the
CPU board.
