Epson 4003353 - Manual (Page 50)

Operating Principles
Drive Circuit
The pnnthead drive circuit for this printer is composed of the following two parts:
■ Common drive circuit (trapezoidal drive pulse generation)
Head drive circuit (nozzle control theprinthead)
The W-bit thermal head driver in the head drive circuit on the carriage is used as a
nozzle selector to selectively drive the nozzles. Print data is into serial data by
gate array and is output from port (pin 20) to the black head drive or
output from port (pin 24) to the color head drive circuit. Then, head driver latches
the head data when gate array E05A96BA outputs the BLAT or signal, and the latched data
64-bit parallel data the black head, or 48-bit parallel data for the color head. One bit
corresponds to each nozzle.
When data transfix and nozzle selection is complete, gate array outputs the comrnon drive
pulse or (charge pulse) and or (discharge pulse) to the drive
The common drive circuit then generates the trapezoidal pulse and applies it to the
as a common drive pulse. After this, the nozzle selected by the head data is activated to
inject ink.
VH
---------------------- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - - - - . - - . . . - - . - - - - -- - - -
Tc: Charge time 82-88 Pc: Charge pulse 92
Th: Idle time 3 Ph: Idle pulse 2 Head drive voltage 16-26 V
Td: Discharge time Pd: Discharge pulse 10
Figure 2-24. Trapezoidal Drive Wave Form
‘ ; : ●
19 ● Row A
1 I I
CCL’
“
23
-1
C137 MAIN
0048-33 ● Row R (Magenta)
On Carriage (Head Driver Board)
2-25. Drive Circuit Block Diagram Figure
2-20
Rev. A