CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2019-213858, filed on Nov. 27, 2019, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

Field of the Invention

The present disclosure relates to a liquid discharging head configured to discharge liquid from a nozzle.

Description of the Related Art

As a liquid discharging head which discharges liquid from a nozzle, there is a known ink-jet recording head which discharges ink from a nozzle. In the known ink-jet recording head, a pressure chamber communicating with the nozzle is formed to have a width which is 320 μm, a height which is 140 and a length which is 2.5 mm, and to have a taper angle of an inner wall surface of the nozzle which is not less than 10 degrees. Further, in the known ink-jet recording head, the size of the pressure chamber and the taper angle of the inner wall surface of the nozzle are made to be as described above, thereby making it possible to drive the ink-jet recording head at a driving frequency of approximately 10 kHz.

SUMMARY

Here, the liquid discharging head is required to further reduce the size of the pressure chamber and to further increase the driving frequency, from the viewpoint of increasing the speed of discharge and of further reducing the size of the device. However, in the above-described ink-jet recording head, in a case that the size of the pressure chamber is further reduced and that the driving frequency is increased, there is such a fear that the discharge of the liquid from the nozzle might become unstable.

An object of the present disclosure is to provide a liquid discharging head capable of stably discharging liquid from the nozzle even in a case that the size of the pressure chamber is reduced and that the driving frequency is increased.

According to an aspect of the present disclosure, there is provided a liquid discharging head including: a channel unit having a liquid channel which includes: a nozzle arranged at an end part, of the channel unit, on one side in a first direction; and a pressure chamber arranged at an end part, of the channel unit, on the other side in the first direction and communicating with the nozzle; and a piezoelectric element including: a vibration plate arranged on a surface, of the channel unit, on the other side in the first direction and covering the pressure chamber; and a piezoelectric layer arranged on a surface, of the vibration plate, on the other side in the first direction, wherein an area, of the pressure chamber, which is projected in the first direction is not more than 50000 μm2, a diameter of the nozzle is increased from the one side toward the other side in the first direction, and a relationship of: θ+1.5×10−4×S>11 is satisfied, provided that θ is an inclination angle of an inner wall surface of the nozzle with respect to the first direction, and that the area of the pressure chamber is S μm2.

