Various Detector Circuits - Epson TM U200D - B/W Dot-matrix Printer Technical Manual

Operation panel
The operation panel is located on the main circuit board and has 3 LEDs (POWER, ERROR, and
PAPER OUT) and 1 switch (FEED). The POWER LED is driven at the same as +5V is supplied
by the power supply circuit. The ERROR and PAPER OUT LEDs are driven by U5. Switch
detection is also executed by the U5.
U5
32 PF SW
P82
1 ELED/DSW9
P57/T03
80 PLED/DSW0
P56/INT3/TI2

Various detector circuits

When the printer detects paper, the Paper detector at the paper inlet turns input signal to CPU
(U5) low. This Detector also functions as semi-automatic loading detector.
The Detector is provided to detect the print head position. The input signal to CPU (U5)
becomes low when the home position is detected.
A near-end detector is an option that detects the remaining amount of a paper roll. The input
signal to CPU (U5) becomes low when a near-end is detected.
U5
RE
11
P64/AN4
12
P65/AN5
HP DET
9
P62/AN2
NE
GND
2-22 Mechanism Configuration and Operating Principles
+5V
Q35
R54
1 (POWER)
D13
2
Figure 2-20 Operation panel circuit
+5V
+5V
R36
R38
R53
C22 C23 C46
Figure 2-21 Various detector circuits
Q36
R55 R56
1 (PAPER) 1 (ERROR)
D12 D11
2 2
Mechanism 1
+5R
CN8
R40
1
REC
1
2
R37
2
HPC
3
3
R39
4
4
R16
C44
Mechanism 2
CN11
NEC 1
1
2
2
R41
R15
GND
SW2
C17
Printer mechanism
+5V
H.P
GND
R.E
1 2
N.E 1 2
GND
Rev.B