PURPOSE: To prevent a valve from adhering to a valve seat so as to enable the valve to be surely operated, by forcing the valve of a pump, used for an ink jet recorder of on-demand type or the like, to be opened and closed together with a piston as it is driven.
CONSTITUTION: A plunger 4 provides in its end a sliding member part 10 to be inserted into the hole of a piston 3, enabling the both sliding member part and piston to be relatively slided only by a fixed distance, and the piston 3 provides a communication hole 7 communicating a liquid chamber A with a liquid chamber B. Then a valve 11 opening and closing the communication hole 7 is provided in an end face of the plunger 4. The piston 3 is driven by a reciprocating motion of the plunger 4. While the liquid chamber A is connected to an ink tank through a passage 5 and the liquid chamber B is connected to the head of an ink jet through a passage 6. In this way, the valve 11 is forcibly actuated and prevented from easily causing its adherence.
ISAYAMA TAKUO
YAMAZAKI HIROSHI
MATSUMOTO SHIYUUZOU
KATANO YASUO
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