Printer Mechanism Drive Circuit; Print Head Drive Circuit - Epson TM U200D - B/W Dot-matrix Printer Technical Manual

Printer Mechanism Drive Circuit

Print head drive circuit

The head drive signal is output from CPU (U5) pin 64 to 72. Receiving this drive signal, the
transistor array (QM1, QM2) and transistor array (QM3) turn On, Off, and drive the head.
Power supply time to the head is adjusted by the supplied power voltage. CPU (U5) changes the
power voltage between analog and digital at AN0 (pin 7) and decides and controls the head
power supply time according to the internal time table.
In order to prevent damage to the head during excessive printing, a heat Detector has been
installed in the print head. An analog-digital conversion of the partial pressure difference
between the heat Detector and R18 is carried out in AN1 (PIN8) of the CPU (U5) and the
temperature is calculated. If the head is overheating or working improperly, the ERROR LED
flashes.
U5
P60/ANO
P61/AN1
AVCC
AVSS
Rev. B
+24DT +5V
D50
R46
R8
7 V DTC
8 HD TEMP
C29
+
R45
C33
_
+5V
5
C19
6
C31 C30
HEAD1
Q5
HEAD5
HEAD6
Q7
71
P47
HEAD2
67
P43
66 Q12
P42
70
P46
HEAD4
68
P44
69
P45
65
P41
72
P50
HEAD3
64
Q9
P40
HEAD7
HEAD9
Q11
HEAD8
Figure 2-24 Print head drive circuit
TM-U200D/U200PD Technical Manual
+5V
R18
R19
D27 D28
Q4
D32
Q6
D38
QM1
1
RM3
7 8 8 9
5 6
3 4
6 7
1 2
D39
4 5
2 3
D40
1
0
D44 R20
Q8
Q13
D41
Q10
D42
QM2 1
RM4
7 8 8 9
5 6
3 4
6 7
1 2
D43
4 5
2 3
D45
1 D7
0
Mechanism Configuration and Operating Principles
Print head unit
w b h j b g
CN7
FG
1
# 2
2
# 4
3
4 # 6
# 8
5
COM (# 4.6.8 )
6
# 9
7
8 C0M ( # 1.2.9 )
THEM1
9
THEM2
10
11 COM (# 3.5.7 )
# 5
12
# 7
13
# 1
14
15 # 3
+24A