Olivetti JP 90, Service Manual

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1-8
681640J
Ink-Jet Printing:
Each nozzle expels an ink bubble whenever an electrical signal is applied to the corresponding resistive
heating element for a few microseconds.
The small amount of ink that comes into contact with the resistive heating element the moment the
electrical signal is applied boils and begins to vaporize thus creating an ink bubble.
As the ink bubble begins to expand, it pushes the ink out of the nozzle and onto the paper. This ink droplet
is expelled from the nozzle at a rate of about 15 m/sec.
Figure 1-4a/e shows the highlights of how an ink bubble is created and expelled from the nozzle.
When the resistive heating element is no longer energized and the ink droplet exits from the nozzle, new
ink from the cartridge replaces the ink that was expelled onto the paper.
A new signal can now be applied to the heating element so that another ink bubble can be created.
NOZZLE
H E A T I N G
ELEMENT
Fig. 1-4a
INITIAL STAGE
Fig. 1-4e
NEW INK FROM THE CARTRIDGE REPLACES
THE DROPLET THAT HAS BEEN EXPELLED.
Fig. 1-4d
THE INK BUBBLE BREAKS AND THE INK IS
PROPELLED ONTO THE PAPER.
Fig. 1-4c
THE INK BUBBLE EXPANDS TO ITS
MAXIMUM SIZE.
Fig. 1-4b
AN ELECTRICAL SIGNAL IS APPLIED TO
THE HEATING ELEMENT AND AN INK
BUBBLE IS CREATED.
THE INK EXITS FROM THE NOZZLE.
Fig.1-4 Creation of an Ink Droplet
INK