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EPSON Stylus Color 900 Revision C
Operating Principles Electrical Circuit Operation Principles 62
[Sensor circuit]
The sensors attached to the printer are as described in the following
pages. They are basically divided into 2 major parts: 1) abnormal
temperature detection part and 2) mechanism status detection part. The
former is controlled by the CPU and the latter is controlled by 2 ASICs;
E05B59 (IC2) and E05B60 (IC3).
1) Abnormal temperature detection part
This abnormal temperature detection part is composed of 3 thermisotrs
and the temperature detection circuit which is included in the nozzle
selector inside the printhead. The CPU’s analog ports used for
temperature detection and their functions are as follows:
Figure 2-13. Sensor Circuit Block Diagram (Abnormal Temperature Detection Circuit)
ANODE5
CN8
CN9
THM
N ozzle
Selector
4
H D64F2357(IC1)
Therm istor on the heat
sink on the m ain board
Location (TH 1) on the board
AN7
AN6
AN5
AN4
AN3
AN2
AN1
AN0
112
111
110
109
108
107
106
105
19
21
20
1
2
9
10
HDSAMI
HPDSAMI
THM
ANODE1
ANODE2
ANODE3
ANODE4
Printhead surface
Inside the printhead
Row A
Row C
Row D
Row E
Row B