Epson SQ-1170, Service Manual

Page: 74 / 176

REV.-A
(1) Charge/discharge circuit
Figure 2-44 shows the circuit,
VH
R35
o
Q3
HI-48
6322 9)
Rs
o
G
0 -
GH
Figure 2-44. Charge/Discharge Circuit
Charge pulse >
When the gate array outputs HIGH pulse from port, the transistors go ON and
thus the Vh voltage charges the elements through the diode and resistor
Figure 2-45 shows the head condition at this time.
Element
Figure 2-45. Head Charge Condition
Discharge pulse >
The data for 48 nozzles stored in the gate array is serially transmitted from HDDAT port to
the printhead drive 16322). Following this, the discharge pulse is transmitted from
to 16322. The 16322 then discharges according to the print data to cause the nozzles
to inject ink. is always charged by Vh.)
For cleaning operation, the sends signal to 16322, which automatically
discharges ail the elements to cause all the nozzles to inject ink.
Figure 2-46 shows the nozzle in discharge condition.
Figure 2-46. Head Discharge Condition
2-35