Epson U675 - TM Color Dot-matrix Printer, Service Manual

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Rev.D Product Overview Appendix D-63
TM-U675/U675P (with autocutter) Service Manual
Confidential
The magnetic reader head recognizes the magnetized characters as shown below.
The voltage waveform output from the magnetic reader head is different for each character,
making it possible to recognize each individual character.
Detection Circuits
This printer has detection circuits for paper and various mechanisms. The detection functions
are described in the table below.
Figure D-60
Figure D-61
Table D-12 Detection circuits
Detector Function
Type of
Sensor
Circuit
TOF Slip detection Transparent
photo Voltage drop of load resistor (R69) is read by the AD port of the
CPU
BOF Slip detection Transparent
photo Voltage drop of load resistor (R68) is read by the AD port of the
CPU
Paper
ejection Slip detection Reflective
photo Voltage drop of load resistor (R66) is read by the AD port of the
CPU
Validation Slip detection Reflective
photo Voltage drop of load resistor (R68) is read by the AD port of the
CPU
Paper
Insertion Paper roll
detection Reflective
photo Logical judgment of voltage drop of load resistor (R147)
Near Paper
End Paper roll
detection Microswitch Logical judgment of switch status by the CPU port.
Voltage Power source
voltage Voltage
potential
divider Potential divider ratio of 24V power source voltage 1/7.2 (R71,
R76) is read by the AD port of the CPU
I
S S N N S S N N
0 1