STYLUS 800 Service Manual Operating Principles
Principles of the Printing Operation
The operation of the
printhead
to inject ink from each nozzle is:
(1) Normal state
No electrical charge is applied to the
MLP
(Multi-Layer
Piezoelectric)
element attached to the back
of the cavity, and pressure inside the cavity is kept at constant level.
Nozzl
(2) Injecting state
The head data signal is applied to the specific nozzle control line to select the active nozzle for
printing, and the
MLP
element is gradually charged by the drive voltage. By charging the
MLP
element, the vibration plate is bent to compress the cavity. Then, ink is injected from the nozzle.
@
Figure 2-3. Principles of the Printing Operation
When the ink charge or
printhead
cleaning operation is performed, the ink in the cavity is
vacuumed out with the pump mechanism. During printing, on the other hand, the ink is
simultaneously supplied from the ink
cartridge
and
injected from the nozzle, according to the
change of volume in the cavity.
A thermistor is attached to the
printhead
drive board to monitor the temperature, because the
viscosity of the ink varies, depending on the temperature.
The detected temperature level is fed
back to the
printhead
drive voltage control circuit to regulate the drive voltage to a proper level.
Rev.
A
2-3