2-10
Operation Principles
Rev. A
Confidential
Platen-open detector mechanism
The platen-open detector mechanism has a
microswitch
which detects whether the
platen
is
open (printing impossible because the
thermal
head
is away from the
platen
) or closed
(printing possible). The
microswitch
can be OFF only when the
frame, platen
is perfectly
closed, and at all other times is ON.
Figure 2-13 Platen-open detector circuit
Head temperature detector mechanism
The
thermal head
has a
thermistor
to detect the temperature of the
thermal head
.
Black mark detector mechanism
The black mark mechanism is a device which can be attached inside the paper guide mechanism
to determine the printing position when using pre-printed thermal paper. This mechanism uses
the reflective photo sensor.
Figure 2-14 Black mark detector circuit
<printer side>
Pin No.
platen open
platen open
Pins 14 and 15 can be reversed.
14
15
SW2
SW1
Pin No.
black mark detector
output
<printer side>
220
Ω
0 to 100 K
Ω
10 K
Ω
13
V
DD
12
7, 8, 10
GND