Fluid ejection device and method of controlling fluid ejection device

1. A tissue removal device which removes tissue by ejecting a fluid at a high speed, the device comprising:

a fluid chamber;

a volume varying unit configured to vary the volume of the fluid chamber;

a fluid supplying unit configured to supply fluid to the fluid chamber; and

an ejection command switching unit configured to switch a fluid ejection between a pulsed flow ejection which ejects the fluid in a pulsed manner by activating the volume varying unit and a continuous flow ejection which ejects the fluid with a fluid supply pressure from the fluid supplying unit higher than that in the case of the pulsed flow ejection, wherein the volume varying unit is stopped during continuous flow ejection.

2. The tissue removal device according to claim 1 , wherein a cross-sectional area A of a fluid ejection opening from which the fluid is ejected has a relationship:

2.57π×10 −9 (m 2 )≦ A≦ 22.5π×10 −9 (m 2 ),

where A (m 2 ) is the cross-sectional area of the fluid ejection opening, and

the ejection command switching unit increases the fluid supply pressure to a value which provides a flow rate of the fluid supplied from the fluid supplying unit of at least 20A (m/sec)*(m 3 /sec.) when performing the continuous flow ejection.

3. The tissue removal device according to claim 1 , the switching unit being configured to switch between the pulsed flow ejection and the continuous flow ejection according to the remaining amount of the fluid supplying unit.

4. A method of controlling a fluid ejection device comprising:

supplying fluid to a fluid chamber; and

switching a fluid ejection between a pulsed flow ejection which ejects the fluid in a pulsed manner by varying a volume of the fluid chamber using a volume varying unit and a continuous flow ejection which ejects the fluid while maintaining the volume of the fluid chamber,

wherein

the switching includes performing the continuous flow ejection with a pressure of the fluid to be supplied to the fluid chamber higher than that in the case of the pulsed flow ejection, and

wherein the volume varying unit is stopped during continuous flow ejection.

5. A tissue removal device which removes tissue by ejecting a fluid, the device comprising:

a fluid chamber;

a bubble generating unit configured to generate bubbles in the fluid chamber;

a fluid supplying unit configured to supply fluid to the fluid chamber; and

an ejection command switching unit configured to switch a fluid ejection between a pulsed flow ejection which ejects the fluid in a pulsed manner by activating the bubble generating unit and a continuous flow ejection which ejects the fluid with a fluid supply pressure from the fluid supplying unit which is higher than the fluid supply pressure in the case of pulsed flow ejection, wherein the bubble generating unit stops generating bubbles during continuous flow ejection.