PURPOSE: To prevent the generation of the irregularity of the sound pressure applied to an ink jet, by arranging an ultrasonic wave absorbing member to the absorbing end part of an ink flow passage and absorbing and attenuating the advance wave of the ultrasonic wave propagating through the ink flow passage to prevent the reflection of the ultrasonic wave.
CONSTITUTION: An ultrasonic wave absorbing device block 18 is mounted to one end of a cylindrical pipe 1 which is, in turn, engaged with and fixed to an ultrasonic wave generator block 17. The leakage of ink between the cylindrical pipe 1 and the block 18 is prevented at the leading end of the cylindrical pipe 1 by an O-ring 14 and at the outer periphery thereof by an O-ring 19. Silicon rubber 25 as an ultrasonic wave absorbing member is arranged to the end part of the ultrasonic wave absorbing device block 18 and, as the silicone rubber 25, one near to ink in acoustic impedance and having ink resistance is used. Since the ultrasonic wave absorbing member 9 is formed into a knife edge shape at the leading end thereof and prepared from an acoustically soft member, an ultrasonic wave is efficiently incident to the absorbing member 9 without being reflected from the surface thereof and gradually attenuated during the repetition of roughness and fineness.
KOIZUMI YUKIHISA
WAKABAYASHI KIMIHIRO
| JPS63176154A | 1988-07-20 |