| 摘要 |
PURPOSE:To eliminate lack of ink-jetting capability due to sticking of a valve at the time being left to stand still for a long period of time, by a method wherein a negative pressure is generated inside a cylinder by moving a piston in one direction so that an ink is sucked in, and the valve is released by a positive pressure which is generated by moving the piston in the other direction. CONSTITUTION:The piston 32 movable in at least two directions is provided in the cylinder 31, and the ink-jetting capability is restored by the negative pressure generated by moving the piston 32 downwardly. In addition, the piston 32 is moved downwardly to generate a high pressure inside the cylinder 31, thereby releasing the stuck valve. It is preferable to provide a piston resetting spring 35 on the lower side of the piston 32. Also, a resetting spring 36 for pressurizing which has a spring constant larger than that of the spring 35 is preferably provided on the upper side of the piston 3. The normal position of the piston 32 within the cylinder 31 is determined by the spring 36, to that a negative pressure is generated when the piston 32 is pushed downwards against the force of the spring 35 and a positive pressure is generated when the piston 32 is pulled upwards against the force of the spring 36. |
