Epson SQ-B50/2550 Technical Manual page 105

REV.-A
2.4.1.7 Paper-end Sensor and Top-edge Sensor
This section describes the basic operating principles of the PE (paper-end) and TE (top-edge) sensors.
The PE sensor is located beneath the platen and paper guide, and senses the presence or absence of
paper. Sensing is performed using a photo-interrupter.
If paper is supplied and the lever is depressed, the lever that normally covers the photo-sensor will be
released, and a LOW signal will be output.
The TE sensor detects the presence or absence, at the paper bail, of the top edge of the paper. Operation
is as follows. The TE roller is linked to the photo-interrupter through the lever. If the paper-end is present,
there will be pressure on the roller, which will cause the lever that normally covers the photo-sensor
to be released, which in turn will cause a LOW signal to be output.
Paper feed, paper eject, paper changeover, and the TEAR OFF function are controlled in accordance
with the signals generated by the PE and TE sensors.
For both PE and TE sensors:
Detection Method:
Collector withstand voltage:
Shunt regulator:
Ph oto-i nte rru pte r
30VDC
O.3mA or less (at 10VDC)
Paper feed roller PE sensor lever
TE holder
TE sensor lever
Platen
Lower paper guide
Figure 2·39. PE Sensor and TE Sensor
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