Printing Head Position Sensor; Paper Tape Presence Detectors; Overall Time Diagram; Fig. 3.6 Outer Part Of The Head Position Sensor - ELCOM Euro-500 Handy Series Service Manual

Euro-500TX Handy

3.4 Printing head position sensor

This sensor detects whether the printing head is up or down. Activation of the head in its top position could
destroy the head or drastically decrease the head durability. The circuit and software were designed so that
the printing head cannot be possibly activated in its top position.
Type
Head up
Head down
Specification

3.5 Paper tape presence detectors

The printer has an internal paper tape presence sensor for the journal tape (output signal PS2x). Head
activation without paper in the printer can destroy the head or drastically decrease its durability. There is an
external paper tape presence sensor for the receipt tape (used photoconductive detector TCST 1103).
VCC1
R31
68k
PS2

Fig. 3.7 Sensor circuit on the main PCB

3.6 Overall time diagram

F A
F B
F A
F B
DATA IN
CLOCK
LATCH
STB1
STB2
STB3
STB4
30
Service manual
photoconductive detector
log. "0"
log. "1"
diode: I = 50 mA maximum
F
U = 6 V maximum
R
transistor: U = 35 V maximum
CEO
I = 20 mA maximum
C
VCC1
R74
68k
PS1
576 bits

Fig. 3.9 Overall time diagram

HS
Fig. 3.6 Outer part of the head position
sensor
VCC1
X
Fig. 3.8 External sensor circuit on the Inter-
connect PCB
576 bits 576 bits
50 100
dots dots
60 100
dots dots
30
dots
30
dots
© Elcom, s. r. o.
VCC1
X
R53
47k
R7
470R
R10
LEDPS1+
470R
R8
LEDPS2+
220R
576 bits
10
dots
10
dots
100 10
dots dots
100 10
dots dots