Rev.D Product Overview Appendix D-11
TM-U675/U675P (with autocutter) Service Manual
Confidential
Roll paper end detector mechanism
The roll paper end detector mechanism detects the presence of roll paper. It is located behind
the sub paper feed roller in the roll paper feed path so that it can detect the insertion of paper
when semi-automatically loading roll paper.
The roll paper end detector includes an LED and a phototransistor. The reflection of light is
used to detect the presence of paper.
When there is paper in the feed path, or when you are performing semi-autoloading, LED light
is reflected when the roll paper is inserted. This changes the output level of the phototransistor.
The change in output level is detected and is used as the detection signal for the presence of roll
paper.
Figure D-16
GND
High
+5V
GND
Low
When light is
interrupted
When light is emitted
Printer side
Roll paper
Signal level at point A
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