EPSON Stylus COLOR C70/C80
Revision A
Operating Principles
Electrical Circuit Operating Principles
58
2.2.2.5 EEPROM Control Circuit
Since EEPROM is nonvolatile memory, it keeps written information if the printer
power is turned off. When the printer is turned ON, CPU (IC7) reads data from
EEPROM (IC6 : Stylus COLOR C70, IC18 : Stylus COLOR C80) via the RAM and
when the power is turned OFF it stores data to EEPROM via the RAM.
Information stored in EEPROM is listed below.
Various ink counter (I/C consumption counter, waste pad counter, etc.)
Mechanical setting value (Head ID, Bi-D adjustment, USB ID, etc.)
See Table 7-8, “EEPROM Address Map,” on page 187 that provides detailed
information on the values stored in EEPROM.
Figure 2-31. EEPROM Circuit Diagram
EEPROM is connected to CPU with 4 lines and each line has the following function.
CS:
Chip selection signal
SK (CLK):
Data synchronism clock pulse
DI:
Data writing line (serial data) at power off.
DO:
Data reading line (serial data) aPEPEt power on.
NOTE:
Items with brackets are for the C80, and items without brackets are for
the C70.
2.2.2.6 Sensor Circuit
C424 MAIN-B is equipped with the following one sensor to detect the status of the
printer. Unlike the previous product, ASF HP sensor and HP sensor are not equipped
and the ASF HP is determined with the clutch mechanism (“Paper Feeding
Mechanism”).
PE Sensor
This sensor uses photo interrupter method and detects the following two status.
The photo interrupt component and two detection levers consists of this sensor.
Paper Top & End position
When the Paper is in the paper path, this sensor outputs the HIGH signal.
When the Paper is not in the paper path, this sensor outputs the LOW signal.
This status is always monitored during the printer is in the power on status
with this sensor.
Thermistor (THM)
The thermistor is attached directly on the printhead driver board. It monitors the
temperature around the printhead and determines the proper head drive voltage
according to the ink viscosity that varies by the temperature. This information is
fed back to the CPU analog port. When the temperature rises, the head drive
circuit lowers the drive voltage: When the temperature lowers, the head drive
circuit rises the drive voltage. This circuit is different from head inside
temperature detection circuit. (Please refer to page -56 for details.)
Linear Scale & CR Encoder
To make the current CR position manage, CR encoder always monitors the bar-
code on the linear scale during CR motor drivers. Also this model has no HP
sensor and judges the home position when the CR goes out of step at right side.
Rotary Scale & PF Encoder
To make the paper feed pitch precisely. PF encoder always monitors the bar-code
on the rotary scale during PF motor drivers.
The block diagram for the sensor circuit is shown below
IC7
E01A27CA
IC18 (IC6)
EEPROM-93C
+5V
8
7
5
VCC
NC
ORG
GND
DO
DI
SK
CS
166
167
168
171
ECS
ECK
EDI
EDO
4 (2)
3 (3)
2 (4)
1 (5)
6
+5V
(CLK)
Summary of Contents for Stylus Color C70
Page 1: ...EPSONStylusColorC70 C80 Color Inkjet Printer SEIJ01 004 SERVICE MANUAL ...
Page 5: ...Revision Status Revision Issued Date Description A July 31 2001 First Release ...
Page 9: ...C H A P T E R 1 PRODUCTDESCRIPTION ...
Page 35: ...C H A P T E R 2 OPERATINGPRINCIPLES ...
Page 60: ...C H A P T E R 3 TROUBLESHOOTING ...
Page 96: ...C H A P T E R 4 DISASSEMBLYANDASSEMBLY ...
Page 137: ...C H A P T E R 5 ADJUSTMENT ...
Page 169: ...C H A P T E R 6 MAINTENANCE ...
Page 182: ...C H A P T E R 7 APPENDIX ...
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