Tally Dascom 7010, Maintenance Manual

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2-1. Operation of Each Mechanism
2-9
Detecting labels: (Media Sensor menu: “See Through”)
For detecting label on the liner, both reflective sensor and transparent sensor are used. Label
paper passes through between both sensors. The light emitted from the LED of the transparent
sensor passes through the media and reaches the phototransistor of the reflective sensor. In liner
part and label part, the amount of light that can pass through differs. Thus, the current flowing into
the phototransistor differs, and the output of the phototransistor also differs.
From the difference in outputs, the CPU on the Main PCB can detect the leading edge of label.
Detecting U-shaped notches of tag: (Media Sensor menu: “See Through”)
For detecting U-shaped notches of tag, the same principle as for detecting label applies, except
that the light is directly falls on the phototransistor through the notch.
Detecting black marks on tag: (Media Sensor menu: “Reflect”)
For detecting black marks on tag, only the reflective sensor is used. Light emitted from the LED is
reflected by the tag (at other than the black mark) and reaches the phototransistor of the reflective
sensor. At the black mark, the light is not reflected. The CPU on the Main PCB detects the black
mark by sensing the output of the phototransistor.
Detecting continuous media: (Media Sensor menu: “None”)
For detecting continuous media, only the reflective sensor is used. In this case, only media end is
detected by the reflective sensor.
Detecting media end:
For any media, media end is detected with the sensor.