Discharge head and droplet discharging device
A discharge head 10 (in illustrated embodiments) for discharging droplets from discharge ports can withstand high water pressure and is provided with a first orifice plate 3 having first discharge ports 3 a and a second orifice plate 6 having second discharge ports. The first orifice plate 3 and the second orifice plate 6 are separated from each other in the liquid discharge direction of the discharge head 10 and disposed opposite to each other. The diameter of the discharge ports of the second orifice plate 6 is smaller than the diameter of the discharge ports 3 a of the first orifice plate 3 so that very fine droplets 9 are discharged from the discharge head 10 as the liquid discharged from the discharge ports 3 a of the first orifice plate 3 is split by the second discharge ports.
1. A discharge head to be used for a droplet discharging device for discharging liquid from discharge ports by exerting pressure, comprising:
a first orifice plate having first discharge ports of a first discharge port diameter;
a second orifice plate arranged parallel to and at a position separated from said first orifice plate in the liquid discharge direction, said second orifice plate having second discharge ports of a second discharge port diameter; and
a plate-securing member located between said first orifice plate and said second orifice plate and connected to both said orifice plates,
wherein said plate-securing member has a hollow space extending in the liquid discharge direction and connecting said first discharge ports and said second discharge ports such that a cross-section of said hollow space taken along a plane running parallel to said orifice plates becomes smaller as one approaches said first orifice plate or said second orifice plate, and
wherein said second discharge port diameter is smaller than said first discharge port diameter.
2. The discharge head according to claim 1 , wherein said second orifice plate has a plurality of second discharge ports arranged opposite to said first discharge ports.
3. The discharge head according to claim 1 , wherein said first orifice plate and said second orifice plate are disposed such that the liquid discharged from said first discharge ports is turned to droplets before reaching said second orifice plate.
4. The discharge head according to claim 1 , wherein said second orifice plate has a thickness smaller than that of said first orifice plate.
5. The discharge head according to claim 1 , wherein said first orifice plate and said second orifice plate satisfy relationships of T 1 >T 2 , D 1 >D 2 and (T 1 −T 2 )/D 22 >T 1 /D 12 , where T 1 is the thickness of said first orifice plate, D 1 is said first discharge port diameter, T 2 is the thickness of said second orifice plate and D 2 is said second discharge port diameter.
6. The discharge head according to claim 1 , wherein the distance between adjacent discharge ports of said second orifice plate is not less than said diameter of said second discharge ports and not more than said diameter of said first discharge ports.
7. The discharge head according to claim 1 , wherein said diameter of said first discharge ports is not less than 10 μm and not more than 500 μm.
8. The discharge head according to claim 1 , wherein the distance between said first orifice plate and said second orifice plate is not less than 300 μm and not more than 50 mm.
9. The discharge head according to claim 1 , further comprising a liquid collecting section arranged between said first orifice plate and said second orifice plate to collect the liquid that was discharged from said first discharge ports but did not pass through said second discharge ports.
10. The discharge head according to claim 1 , further comprising an energy application mechanism for applying thermal energy, oscillation energy or charging energy to said second orifice plate.
11. The discharge head according to claim 1 , wherein said orifice plates are so disposed and arranged that the contact angle of liquid relative to the surface of said second orifice plate is greater than the contact angle of liquid relative to the surface of said first orifice plate.
12. A droplet discharging device comprising:
a discharge head according to claim 1 ;
a pressure exerting mechanism for applying pressure in order to cause said discharge head to discharge liquid; and
a flow path for supplying the liquid pressurized by said pressure exerting mechanism said discharge head.
13. The droplet discharging device according to claim 12 , wherein the liquid ejected from said discharge head is a liquid medicine to be inhaled by a user.
14. An inhaler provided with a liquid discharging device according to claim 13 .