Epson Stylus Color 640 Service Manual page 75

EPSON Stylus Color 440/640/740
CXA20996(IC14)
22
VCC45
23
Vcc45_2
A0
20
NPNB
A1
18
FB
A2
PNPB
A3
16
CLK1
+5
CLK2
24
/FLOOR
VCC5
/RST
DATA
DCLK
/E
14
VOUTGND
E05B588(IC2)
VHCTL 190
SWC0
189
HWA0
SWC1
HWA1
184
HWA2 HLAT
173
HWA3
HNCHG
HWCLK1
174
HWCLK2 HCLK
175
/HWFLR
IECLK
/HWRST
176
HSI1
HWSDATA
177
HWSCLK
HSI2
/HWSLAT
178
HSI3
179
HSI4
180
HSI5
181
HSI6
TMP95C061(IC1)
105
AN0
Figure 2-34. Head Drive Circuit for Stylus Color 740
Chapter 2 Operating Principles
+42
F1
CN9
27
VHV
26
COM
25
COM
24
COM
23
COM
22
GND2
21
GND2
20
GND2
19
GND2
1
BCO
2
CCO
5
LAT
16
NCHG
14
CLK
12
SI1
11
SI2
10
SI3
9
SI4
8
SI5
7
SI6
3
THM
+5
18
GND
17
GND
15
GND
13
GND
6
GND
4
GND
[Common drive circuit]
The shape of trapezoidal wave form will be different according to the
printing operation, slight vibrations at the non-printing nozzle and
waiting condition. However, the IC6(for Stylus Color 440), IC7(for Stylus
Color 640), IC14(for Stylus Color 740) generates all wave forms as
drive wave forms by resistance(electric) welding control of common
voltage drive control signal that is output from the IC2(gate array) in the
figure above.
Specifications of H8D2813/CXA20995 for Stylus Color 440, 640, 740
Items
Drive Power Voltage 42 5%
Starts supplying after 5V rises and be stabilized./
Stops supplying before +5V drops.
Final Drive Element 2SC3746(for charging),
2SA1469(for discharging)
Operation at the Reset Off on the both charging and discharging sides.
Supplies drive power source.
This common voltage trapezoidal wave form can be observed anytime
after the +5V rises even if there is printing data or not. (Q7:3-pin,Q9:3-
pin for Stylus Color 440 and Q2: 3-pin, Q3: 3-pin for Stylus Color 640,
740)
[Nozzle Selector Drive Circuit]
In order to motivate the print head to carry out printing, it is necessary to
transmit the printing data to the appropriate nozzles, which becomes
direct signals to drive PZT. This data transmission is performed by the
serial method, however the data output for each black and CMY head is
transmitted by the parallel method.
Revision A
Table 2-9.
COntents
75