| 摘要 |
PURPOSE:To keep the speed of an ink almost constant even if the droplet volume is changed to prevent recording distortion, by determining a nozzle shape and the viscosity resistances of a check valve and an ink passage so that a time required in bringing the flow speed of ink injected from a nozzle to a steady state after a voltage pulse is applied becomes shorter than the min. width of the voltage pulse. CONSTITUTION:An ink jet head is constituted of a nozzle 1, a pressure chamber 3, an ink supply port 4 and check valves 5, 6 for inhibiting the flow in the direction of the ink supply port 4. When voltage having polarity for reducing the volume of a pressure chamber 3 is applied to an electromechanical conversion element 2, the ink is injected from the nozzle 1 while passing the check valve 5. When voltage is returned to original one, the ink is sucked from an ink supply port through the check valve 6. By determining the resistance of the check valve flow passage so that time constant determined by the inertia resistance of the nozzle and the normal direction resistances of the flow passage and the check valves becomes shorter than the variable range of a driving pulse width, it is possible to change the volume of the ink droplet while keeping the speed thereof constant. |
