Service manual

EPSON Stylus Color 400 Service Manual
Rev.A
2-2
8
[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. The figure below shows data transmission circuit.
CLK(Clock) pulse considered as source of serial communication is commonly used for both black and
CMY. The serial data transmits data as 64-Clock unit, synchronizing with this pulse. After the data
transmission of 64-Clock is completed, LAT(Latch) signal is activated and is hold temporarily in the
IR2C72C. At this time, since the number of nozzle for Color head is fewer(21-nozzle) and different from
the ones for black head, 0 is transmitted forcefully for the data for 43 nozzle (64-21=43).
VH
COM
NCHG
CLK
SI1
SI2
LAT
THM
CN8
SI0(for black)
SI1(for colr)
SCLK
LAT
XCHG
COM
VHV
VD1/2
Gate Array
E05B43(IC2)
U101
IR2C72C
Black Data
Latch
Color Data
Latch
Black Nozzle
Color Nozzle
Figure 2-25. Nozzle Selector Circuit Block Diagram