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.
Two types of sensors are used in this printer. Release sensors 1 and 2, the PG sensors, and the front PE sensor
are momentary switches. Pages 2-3 and 2-4 describe the relationship between release and PG sensor
operation and actual print operation.
The HP sensor, rear PE sensor, and PW sensor 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 voltage it measures with a standard voltage that was measured during the power on
sequence.
Additionally, as mentioned on the page 2-24, the +35 V line and head temperatures are monitored to set the
pulse length of the head driver signal.
C P U
P 3 6
P 4 0
A N 2
P 5 3
P 2 7
+ 5 V
PG Sen sor
+ 5 V
+ 5 V
HP Se n so r
+ 5 V
+ 5 V
Re ar PE
Sensor
+ 5 V
Front PE
Sensor
+ 5 V
+ 5 V
P W S e n s o r
6 1
7 6
7 5
6 8
7 0
Relea se
Senso r 1
6 7
6 8
Gate
Array
R2
R1
Relea se
Senso r 2
Figure 2-38 Sensor Circuit
LQ-2070 Service Manual
Operating Principles
Rev.A
2-27
Содержание 2070 - LQ B/W Dot-matrix Printer
Страница 1: ...EPSON TERMINAL PRINTER LQ 2070 SERVICE MANUAL EPSON 4006244 ...
Страница 5: ...REVISION SHEET Revision Issued Date Revision Page Rev A April 8 1996 1st issued ...
Страница 11: ...Product Description LQ 2070 Service Manual Figure 1 1 Exterior View of the LQ 2070 1 2 Rev A ...
Страница 55: ...LQ 2070 Service Manual Operating Principles Rev A 2 7 ...
Страница 58: ...Operation Principles LQ 2070 Servcie Manual 2 10 Rev A ...
Страница 63: ...Down LQ 2070 Service Manual Operating Principles Rev A 2 15 ...
Страница 112: ...Disassembly and Assembly LQ 2070 Service Manual 3 34 Rev A ...
Страница 146: ...Maintenance LQ 2070 Service Manual 6 4 Rev A ...
Страница 165: ...EPSON ...