Patent ID: 8720434

Claim:
A medicine ejection device for ejecting a medicine, comprising: a medicine ejection portion having an ejection nozzle and an element that generates energy for ejecting a medicine from the ejection nozzle; a medicine storing portion that is connected to the medicine ejection portion and stores the medicine therein, the medicine storing portion being blocked from outside air except for a path through the ejection nozzle; a movable wall, which is displaced by a pressure difference between an inside and an outside of the medicine storing portion caused by an ejection of the medicine through the ejection nozzle to decrease a volumetric capacity of the medicine storing portion; a pressure unit for pressurizing the movable wall so as to decrease the pressure difference; a reading unit for reading a displacement of the movable wall corresponding to an ejection amount of the medicine and providing a reading result; and a controller that computes, based on the reading result obtained from the reading unit, a period between a time when the ejection has started and a time when the movable wall starts moving or a moving speed of the movable wall, and changes a driving condition of the medicine ejection portion so as to increase an ejection amount per unit hour when the period between the time when the ejection has started and the time when the movable wall starts moving is longer than a predetermined period of time, or when the moving speed of the movable wall is smaller than a predetermined speed.