Ink droplet jet device

An ink droplet jet device comprising:

• a piezoelectric plate having plural grooves formed therein defining ink channels, the grooves being delineated by upstanding side walls in the piezoelectric plate, the side walls having upper surfaces;
• and
• a nozzle plate secured to the piezoelectric plate at an end of the ink channels by an adhesive agent having a Young's modulus and a thickness,
• wherein a value obtained by dividing the Young's modulus of the adhesive agent by the thickness of the adhesive agent is 1.times.10.sup.6 kg/mm.sup.3 or less and greater than zero so that the adhesive agent has an optimal elasticity to maintain a volume variation in the ink channels, due to a piezoelectric effect of the side walls, within a predetermined volume variation amount.

An ink droplet jet device comprising:

• a piezoelectric ceramic plate having plural grooves formed therein defining ink channels, the grooves being delineated by upstanding side walls in the piezoelectric plate, the side walls having upper surfaces;
• a cover plate secured to the piezoelectric plate at the upper surfaces of the side walls by an adhesive agent having a Young's modulus and a thickness;
• and
• a nozzle plate secured to the piezoelectric plate at an end of the ink channels by the adhesive agent,
• wherein a value obtained by dividing the Young's modulus of the adhesive agent by the thickness of the adhesive agent is in a range of 5.times.10.sup.3 kg/mm.sup.3 and 1.times.10.sup.6 kg/mm.sup.3 so that the adhesive agent has an optimal rigidity and elasticity to maintain a volume variation in the ink channels, due to a piezoelectric effect of the side walls, within a predetermined volume variation amount to ensure stable jetting of ink droplets.