Page 576 - Book Hosokawa Nanoparticle Technology Handbook

APPLICATIONS 30 NOZZLE-FREE INKJET TECHNOLOGY

Droplet was shoot

Liquid surface was raised Unstable state by balance of emission pressure
by emission pressure of and surface tension
ultra sonic

Figure 30.2
Droplet shooting process by the nozzle-free technique.

Droplet 1000

PC controller Water 25°C
Droplet diameter ( m)
Function 100
Vessel
generator
Partition 10
Burst wave
Water
Power 1
amplifier 1 10 100 1000
Acoustic frequency (MHz)
Ultra sonic vibrator
Figure 30.4
Figure 30.3 Relation between acoustic wave and droplet diameter.
Schematic diagram of the developed system.

these experimental results [1]. Further, in order to direction of propagation of the ultrasonic waves, there
protect the ultrasonic transducer from the corrosive will be reflections of the acoustic wave due to mis-
liquid such as a strong acid, a polyethylene container matching of the acoustic wave impedance. Because
is used for holding the liquid solution of raw material, the reflection of the ultrasonic waves is as less as 1%
a partition wall is provided between the liquid solu- at the interface with water, polyethylene is used as the
tion container and the ultrasonic transducer, and water material for the container. In addition, by making the
is inserted in between as the medium for transmitting thickness of the bottom of the container less than
the acoustic waves. This structure is being adopted for about 300 m, a transmittivity of more than 90% has
replacement of liquid solution reagent, or for contin- been achieved thereby aiming to maintain the effi-
uous spraying of different types of liquid solutions. ciency of the droplet spray. An outline of the develop-
Since different types of materials are arranged in the ment system is shown in Fig. 30.5 [2]. The plate to be

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