EPSON Stylus C110/C120/D120 Revision B
OPERATING PRINCIPLE Electrical Circuit Operating Principles 38
2.3.2.2 Printhead Driver Circuit
The printhead driver circuit consists of the following two components:
Head common driver circuit (Head driver IC11 & Wave amplifier transistor
Q3, Q4)
Nozzle selector IC on the printhead driver
The common driver (IC11) generates a basic drive waveform according to the output
signals from CPU (IC8). The basic drive waveform is amplified by the transistors Q3
and Q4 (the amplified one is called drive waveform.) and then transferred to the nozzle
selector IC on the printhead driver board. Print data is converted to serial data by the
CPU and then sent to the nozzle selector IC on the printhead driver board. Based on the
serial data, the nozzle selector IC determines the nozzles to be actuated. The selected
nozzles are driven by the drive waveforms amplified by the transistor Q3 and Q4.
Refer to
Figure 2-20 (p.38) for the printhead driver circuit block diagram.
Head driver circuit
The basic drive waveform is generated in the head driver (IC7) based on the
following 12 signal lines output from the CPU (IC8); DATA0-DATA9, LAT, and
PSAVE. By the DATA signal output from the CPU, the original data for
generating the head drive waveform is written in the memory in the head driver
(IC7). The addresses for the written data are determined by DATA0-DATA9
signals. Then, the necessary data is selected from the address and appropriate basic
drive waveform is generated. The generated head drive waveform is transmitted to
the nozzle selector IC on the printhead driver board through the transistor Q3 and
Q4 and applied to the nozzle PZT specified by nozzle selector IC.
Nozzle selector circuit
A print data is converted into serial data by the CPU (IC8). The serial data is
divided into three for allocating data to each of the three head columns, and
transmitted to the nozzle selector via three signals (HS01 to HS03). The data
transmission from the CPU (IC8) to the nozzle selector synchronizes with the LAT
signal and SCK clock signal. Nozzles to be used are determined depending on the
transmitted data and PZT for the selected nozzles are controlled by the waveform
output from the head driver.
Figure 2-20. Printhead Driver Circuit Block Diagram
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