2.3.2.5 Printhead Drive Circuit

Thep rinthead drive circuit for thisp rinter is composed of the following two parts:
Common drive circuit(trape zoidal drive pulse generation)
Headdrive circuit (nozzle control built on the printhead)
SED5620D, the 64-bit thermal head driver in the head drive circuit on the carriage, is used as a
nozzle selector to drive the printhead nozzles selectively. Print data is converted into serial data by
gate array E05A96 (IC2) and is output from port BSO (pin 20) to the black head drive circuit or
output from port CSO (pin 24) to the color head drive circuit. Then, head driver SED5620D latches
the head data when gate array E05A96BA outputs the BLAT or CLAT signal, and the latched data
becomes 64-bit parallel data for the black head, or 48-bit parallel data for the color head. One bit
corresponds to each nozzle.
When data transfer and nozzle selection is complete, gate array E05A96 outputs the common drive
pulse BPWC or CPWC (charge pulse) and BPWD or CPWD (discharge pulse) to the common drive
circuit. The common drive circuit then generates the trapezoidal pulse and applies it to the
printhead as a common drive pulse. After this, the nozzle selected by the head data is activated to
injectink.
In the Micro Dot Printing mode, the gate array E05B09 arranges the puise width of CPWC and
CPWD to became small size of injection ink dot.
Normal Dot Mode
Drive Waveform
Micro Dot Mode
Drive Waveform
Head
Common Driver
Drive Pulse
SELM Pulse
SELN Pulse
Block Resistor
Normal
Micro
Figure 2-23. Normal / Micro Dot Mode Switch Block
Operating Principles Stylus Pro XL
2-20 REV.-A