EPSON Stylus COLOR 900/900N
Chapter 2 Operating Principles
58
2.3.9 Cooling Fan Driver Circuit
The cooling fan keeps the temperature of the printhead driver
transistors within their normal operating range. When the transistors
become too hot, it blows air through the heatsink to which they are
attached. The cooling fan also regulates the temperature of the
adjacent printhead pre-driver ICs (IC15 and IC16), located under the
heatsink. The figure below shows the cooling fan driver circuit block
diagram.
Figure 2-21. Cooling Fan Driver Circuit Block Diagram
The cooling fan driver circuit relies on input from two thermistors (“t1”
and “t2” in
). Thermistor
t1 is attached directly to the heat
sink, while
t2 is located on the main board between the printhead pre-
driver ICs. The table below shows the detected temperature and the
corresponding fan operation.
Table 2-15. Detected Temperature and Cooling Fan Operation
IC1 processes the temperature detected by the thermistors every two
seconds, even while the printer is idle, and IC2 outputs a cooling fan
driver signal as shown in the table below:
Table 2-16. IC2 Output and Cooling Fan Operation
Cooling fan on
Cooling fan off
t1
≥
40
°
C or t2
≥
50
°
C
t1
≤
36
°
C and t2
≤
42
°
C
+ 4 2
6 . 8
C N 1 3
G N D
2
1
+ 3 5
3 9 K
E 0 5 B 5 9 ( I C 2 )
1 7 6
F A N
F A N
F 6
D r o p s t o 3 5 V .
IC2 output (pin 176)
Cooling fan operation
High (5 V)
On
Low (0 V)
Off
Summary of Contents for 900N
Page 1: ...EPSONStylusCOLOR900 900N Color ink jet printer TM SC900 N 6 59 0 18 ...
Page 8: ... 37 5 PRODUCTDESCRIPTION ...
Page 37: ... 37 5 OPERATINGPRINCIPLES ...
Page 67: ... 37 5 TROUBLESHOOTING ...
Page 89: ... 37 5 DISASSEMBLYANDASSEMBLY ...
Page 121: ... 37 5 ADJUSTMENTS ...
Page 156: ... 37 5 MAINTENANCE ...
Page 169: ... 37 5 APPENDIX ...
Page 179: ...EPSON Stylus COLOR 900 900N Chapter 7 Appendix 176 Figure 7 3 C265 Main Board Soldering side ...
Page 181: ...EPSON Stylus COLOR 900 900N Chapter 7 Appendix 178 Figure 7 6 C265 PNL Board ...
Page 195: ...06 03 01 02 for S E ASIA 03 03 05 03 04 EPSON STYLUS COLOR 900 No 7 10056 Rev 01 ...
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