BIXOLON SMP685, User Manual, Page: 7 / 43

Rev. E - 7 -
SMP685
※
Design Precautions
Take precautions on following items when designing products such as terminals using the
printer mechanism.
a) Power on sequence should be as follows.
- Startup: Apply Vdd and then Vp
- Shutdown: Shutdown Vp and then Vdd
b) The surge voltage between Vp and GND should be less than 10V.
c) Connect 0.1 uF capacitor between Vdd and GND near to the connector in order to
prevent noise.
d) The resistance of the wire connected between the power supply device (Vp and GND)
and the printer mechanism (terminal connection) should be as low as possible (less
than 50m
Ω
). Leave sufficient space between signal lines to prevent interference.
e) Shutdown Vp supply while the printer is not printing to protect the thermal head from
electrolytic corrosion. Design your system to maintain the same potential for the GND
signal of the thermal head and the frame ground of the printer mechanism.
f) Use C-MOS IC for signals like
CLK, nLAT, SI, and STB.
g) Never use the
STB terminal during power shutdown or when the printer is not printing.
h) Never activate the thermal head if platen roller block is open and there is no paper.
Incorrect activation of thermal head may damage or reduce the lifespan of the thermal
head and the platen roller.
i) The temporary pause time between the activation of the same thermal device should be
at least longer than 0.5 ms. Precautions should be taken when using 1 section printing
or when the thermal head activation time becomes longer. Activation of the thermal
head without pause for a long time may damage the thermal head.
j) Force to feed the paper may be reduced depending on the motor pulse speed. Check
the actual performance while you use the device.
k) Do not move the thermal paper backward. If the thermal paper breaks away from the
thermal head of platen roller, the printer mechanism may not feed the paper or a paper
jam may occur.
l) Continuous printing may cause issues in the printer mechanism due to accumulated heat
in the stepping motor. If there is a need to print continuously for several minutes, stop
the printing the middle and restart the printing when the step motor has cooled down
sufficiently. Check the actual performance while you use the device.