| 摘要 |
PURPOSE:To enable stable recording with high reliability, by setting prescribed opening angles for a longitudinal section including an axis which extends through the center of an orifice parallel to the flowing direction of a liquid. CONSTITUTION:An ink ejection unit 1 comprises a first passage 7 which extends with a length l from the front of an orifice 5 to a dotted line X''Y'' and whose longitudinal section linearly increases at an opening angle alpha from the front of the orifice toward a pressure chamber 2, and a second passage 8 which extends from the dotted line X''Y'' to another XY and whose longitudinal section has a part with the maximum opening angle beta on the side of the orifice 5 and smoothly increases toward the pressure chamber 2. The ink ejection unit 1 is provided on the front of a head. The pressure chamber 2 extends from the dotted line XY extending through an inflection point 6. The pressure chamber has an almost constant inside diameter d and is coupled with an ink feed unit. The length l is set at 0.1-0.7 time of the inside diameter d on the connection point of the pressure chamber 2 with the ink ejection unit, namely, on the dotted line XY. The opening angle alpha is set at 20 deg. or less. The maximum opening angle beta is set at 60-150 deg.. |
