PURPOSE: To generate ink particles stably with an easy adjustment by controlling excitation voltage to the operation area where to keep small-diameter particles from being generated from a nozzle through a regulation of the phase and the component ratio of input signals from an excitation voltage source.
CONSTITUTION: An excitation voltage source 5 is made up of a main amplifier 10 and a preamplifier 11. A relative shift in the phase is adjusted between the first signal component of a frequency F and the second signal component of a frequency 2F with phase shift circuit elements 23a and 23b of the preamplifier 11 while the component ratio of the two signals is adjusted with resistances 24a and 24b. These two factors are added up and an addition signal is applied to the main amplifier 10 providing a band pass filter characteristic with a frequency F. Output signals thereof is applied as excitation voltage Ve to an electric-mechanical conversion element 4 attached to a nozzle 2 to prevent the generation of small-diameter particles thereby enabling the simplification of the structure and adjustment and lower cost.
TANNO KIYOHIKO
TADAUCHI MITSUHARU
YAMADA TAKEHIRO
YOSHINO EIJI
HITACHI KOKI KK