Epson 440 Service Manual page 65

EPSON Stylus Color 600
[Nozzle Selector Drive Circuit]
In order to motivate the print head to carry out printing, it is necessary to transmit the print data to the
appropriate nozzles, which becomes direct signals to drive PZT. This data transmission is performed
by the serial transport method, however the data output for each black and CMY head is transmitted by the
parallel method. The figure below shows data transmission circuit.
Figure 2-25. Nozzle Selector Circuit Block Diagram
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(U101) At this time, since the number of nozzle for Color head is fewer(21-nozzles) and different
from the ones for black head, 0 is transmitted forcefully for the data for 43 nozzle (64-21=43).
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Rev. A