2.5 HOME SWITCH
The home switch is a push-open type mechanical switch, which switches “OFF” when the head is at the
home position (left end). The switch has two functions. The first is to detect the home position when
the head stops there. Upon returning to the home position, the home switch switches from “ON” to
“OFF”, and brakes are applied to stop the motion of the print head.
The second function is it is used as reference point for starting the counting of the print timing signals.
As the head begins to move to the right from the home position, the home switch switches from “OFF”
to “ON”, at which point counting of the print timing signal begins (TG signals after waveform shaping).
(1) Contact resistance
5
Ω
max. (measuring current: 50
μ
A)
(2) Current
1.0 mA max. (5.0 V DC)
(3) OFF-to-ON detection
Figure 2-6 OFF-to-ON Detection
This switch has the characteristics that the ON state exists for more than 100
μ
s within 2 ms of when the
home switch switches from OFF-to-ON. Do not detect the switch until after 1-line has printed after
detection of the first ON detection.
(4) ON-to-OFF detection
Figure 2-7 ON-to-OFF Detection
This switch has the characteristics that the OFF state exists for more than 450
μ
s within 2 ms of when
the home switch switches from ON-to-OFF. Do not detect the switch for 10 ms after detection of OFF.
2-9
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