2.3.7 Sensor Circuits
The CPU detects conditions of the following sensors: home position (HP) sensor, release sensors 1 and 2,
platen gap (PG) sensor, rear and front paper end (PE) sensors, paper width (PW) sensor, and cover open
sensor.
Two types of sensors are used in this printer. Release sensors 1 and 2 , PG sensors, the front PE sensor, and
cover open sensor are momentary switches. Pages 2-3 and 2-4 describe the relationship between release and
PG sensor operation and actual print operation.
The other type of sensor is used for the HP sensor, rear PE sensor, and PW sensor, which are photo diode
switches. The HP sensor detects CR home position when the photo diode rays are cut off by the printhead.
The rear PE sensor detects that paper has been loaded when the photo diode rays are cut off by the sensor
plate, which is included in the rear PE sensor. The PW sensor, used for paper width measurement and paper
loading positioning, detects the paper edge by comparing the measured voltage with standard voltage, which
was measured during the power on sequence.
Additionally, as mentioned on the page 2-24, the +35 V line and head temperature are monitored to set the
pulse length of the head drive signal.
C P U
P 3 6
P 4 0
A N 2
P 5 3
P 3 2
P 3 3
P 3 4
P 3 5
+ 5 V + 5 V
PG S en s or 2
PG S en s or 1
Re le ase
Se nso r 1
Re le ase
Se n so r 2
+ 5 V
+ 5 V
+ 5 V + 5 V
HP S e ns o r
+ 5 V
+ 5 V
Re ar PE
Sensor
+ 5 V
Front PE
Sensor
+ 5 V
+ 5 V
PW Sensor
INT7
+ 5 V
Cover Open
Sensor
18
67
66
65
64
76
75
68
70
Figure 2-38 Sensor Circuits
LQ-2170 Service Manual
Operating Principles
Rev.A
2-27
Summary of Contents for LQ-2170
Page 1: ...EPSON TERMINAL PRINTER LQ 2170 SERVICE MANUAL EPSON 4005735 ...
Page 5: ...REVISION SHEET Revision Issued Date Revision Page Rev A December 5 1995 1st issued ...
Page 11: ...Figure 1 1 Exterior View of the LQ 2170 Product Description LQ 2170 Service Manual 1 2 Rev A ...
Page 80: ......
Page 127: ...1 Abnormal CR Operation LQ 2170 Service Manual Troubleshooting Rev A 5 5 ...
Page 141: ...LQ 2170 Service Manual Troubleshooting Rev A 5 19 ...
Page 156: ...Appendix LQ 2170 Service Manual A 10 Rev A ...
Page 158: ...Appendix LQ 2170 Service Manual A 12 Rev A ...
Page 159: ...Figure A 3 C165 PSB Board Assembly Circuit Diagram LQ 2170 Service Manual Appendix Rev A A 13 ...
Page 160: ...Appendix LQ 2170 Service Manual A 14 Rev A ...
Page 161: ...Figure A 4 C165 PSE Board Assembly Circuit Diagram LQ 2170 Service Manual Appendix Rev A A 15 ...
Page 162: ...Appendix LQ 2170 Service Manual A 16 Rev A ...
Page 167: ...Figure A 9 LQ 2170 Exploded Diagrams 2 LQ 2170 Service Manual Appendix Rev A A 21 ...
Page 168: ...Figure A 10 LQ 2170 Exploded Diagrams 3 Appendix LQ 2170 Service Manual A 22 Rev A ...
Page 169: ...Figure A 11 C S F Bin1 Exploded Diagrams 1 LQ 2170 Service Manual Appendix Rev A A 23 ...
Page 170: ...Figure A 12 C S F Bin1 Exploded Diagrams 2 Appendix LQ 2170 Service Manual A 24 Rev A ...
Page 171: ...Figure A 13 C S F Bin2 Exploded Diagrams LQ 2170 Service Manual Appendix Rev A A 25 ...
Page 172: ...Table A 15 Part No Reference Table Appendix LQ 2170 Service Manual A 26 Rev A ...
Page 173: ...Table A 15 Part No Reerence Table Continue LQ 2170 Service Manual Appendix Rev A A 27 ...
Page 174: ...Appendix LQ 2170 Service Manual A 28 Rev A ...
Page 175: ...EPSON Printed in Japan 95 12 05 S ...