| 摘要 |
<p>PURPOSE:To contract the seal area of a valve so as to have sealing property stabilized by arranging a blocking releasing valve in a discharging hole whose diameter is smaller than that of the penetrating hole of a piston rod in a piston, in a pump for supplying/discharging ink into a cylinder by means of reciprocation of a piston forced by a piston rod. CONSTITUTION:When a piston shaft 3 falls down, the piston push part 3d thereof abuts on the first projection part 2d of a piston 2, so that a valve 4 is closed and a discharging hole 2c is blocked. When the piston shaft 3 falls down further, a piston 2 falls down in one body with the piston shaft 3, and negative pressure is generated in the intake pipe 1a of a cylinder 1, so that ink is sucked from a nozzle. On the other hand, when the piston shaft 3 is raised while inverting from a bottom dead point, the valve 4 is opened. When the piston shaft 3 is raised further, the piston 2 is raised in one body with the piston shaft 3, and ink is discharged into a discharging pipe 1b through the notch part 3e of the piston shaft 3. Since the valve 4 is arrannged in the discharging hole 2c whose diameter is smaller than that of the penetrating hole 2a of the piston 2, the seal area of the valve 4 can be reduced.</p> |
