Liquid jetting head and method for manufacturing the same
A liquid jetting head includes a flow channel substrate formed with pressure chambers, an actuator covering the pressure chambers, and a temperature sensor. A dummy pressure chamber is formed in a surface, of the flow channel substrate, in which the pressure chambers are open. The actuator includes: a vibration plate which covers the pressure chambers and the dummy pressure chamber and which has a first surface facing the pressure chambers and a second surface opposite to the first surface, and a piezoelectric body arranged on the second surface of the vibration plate to face the pressure chambers. The temperature sensor is arranged on the second surface of the vibration plate at a position facing the dummy pressure chamber.
1. A liquid jetting head comprising:
a flow channel substrate in which pressure chambers are formed;
an actuator covering the pressure chambers; and
a temperature sensor,
wherein a dummy pressure chamber is formed in a surface, of the flow channel substrate, in which the pressure chambers are open;
the actuator includes:
a vibration plate covering the pressure chambers and the dummy pressure chamber and having a first surface facing the pressure chambers and a second surface opposite to the first surface; and
a piezoelectric body arranged on the second surface of the vibration plate to face the pressure chambers, and
the temperature sensor is arranged on the second surface of the vibration plate at a position facing the dummy pressure chamber.
2. The liquid jetting head according to claim 1 , wherein the piezoelectric body is not provided at the position facing the dummy pressure chamber on the second surface of the vibration plate.
3. The liquid jetting head according to claim 1 , wherein the dummy pressure chamber is filled with liquid which flows inside the flow channel substrate.
4. The liquid jetting head according to claim 3 , wherein the flow channel substrate is formed with nozzles which communicate with the pressure chambers respectively and from which the liquid is jetted, and a dummy nozzle which communicates with the dummy pressure chamber and from which the liquid is not jetted.
5. The liquid jetting head according to claim 1 ,
wherein the dummy pressure chamber has the same shape and size as each of the pressure chambers,
the pressure chambers and the dummy pressure chamber are arranged at regular intervals along an arrangement direction of the pressure chambers, and
the dummy pressure chamber is positioned at most outside in the arrangement direction among the pressure chambers and the dummy pressure chamber.
6. The liquid jetting head according to claim 1 ,
wherein the pressure chambers are arranged to form one or more pressure chamber rows,
the dummy pressure chamber is one of dummy pressure chambers opening in the surface of the flow channel substrate,
the dummy pressure chambers are arranged in an arrangement direction of the pressure chambers,
the dummy pressure chambers include an adjacent dummy pressure chamber which is adjacent to one pressure chamber row among the one or more pressure chamber rows in the arrangement direction, and a distant dummy pressure chamber which is distant further from the one pressure chamber row than the adjacent dummy pressure chamber in the arrangement direction, and
the temperature sensor is arranged at a position facing the distant dummy pressure chamber.
7. The liquid jetting head according to claim 6 , wherein the temperature sensor is arranged across the dummy pressure chambers.
8. The liquid jetting head according to claim 1 ,
wherein the actuator includes a common electrode which is common to the pressure chambers and arranged between the vibration plate and the piezoelectric body to face the pressure chambers and the dummy pressure chamber, and
the temperature sensor is arranged on the common electrode.
9. The liquid jetting head according to claim 1 ,
wherein the actuator includes individual electrodes corresponding to the pressure chambers respectively,
the individual electrodes are arranged on a surface of the piezoelectric body on a side opposite to the vibration plate at positions facing the pressure chambers respectively, and
an electrode for the temperature sensor is arranged on a surface of the temperature sensor on a side opposite to the vibration plate.
10. The liquid jetting head according to claim 9 , wherein the electrode for the temperature sensor is made of the same material as the individual electrodes.
11. The liquid jetting head according to claim 1 , wherein the temperature sensor is made of a material in which electric resistance is changed depending on temperature.
12. The liquid jetting head according to claim 11 , wherein the material is combined metal oxide.
13. The liquid jetting head according to claim 1 ,
wherein the flow channel substrate is formed with a supply flow channel configured to supply liquid to each of the pressure chambers from a storing chamber storing the liquid, and
the temperature sensor is arranged on an upstream side of the pressure chambers in a flow direction of the liquid in the supply flow channel.
14. The liquid jetting head according to claim 1 ,
wherein the flow channel substrate is formed with a first flow channel through which a first color liquid flows and a second flow channel through which a second color liquid flows,
the pressure chambers are arranged to form one or more pressure chamber row,
the pressure chambers include a first pressure chamber and a second pressure chamber arranged along an arrangement direction of the pressure chambers, the first pressure chamber belonging to the first flow channel, the second pressure chamber belonging to the second flow channel,
the dummy pressure chamber is one of dummy pressure chambers opening in the surface of the flow channel substrate,
the dummy pressure chambers include a first dummy pressure chamber and a second dummy pressure chamber arranged in the arrangement direction, the first dummy pressure chamber being adjacent to the first pressure chamber in the arrangement direction, the second dummy pressure chamber being adjacent to the second pressure chamber in the arrangement direction, and
the temperature sensor includes a first temperature sensor arranged at a position facing the first dummy pressure chamber, and a second temperature sensor arranged at a position facing the second dummy pressure chamber.
15. The liquid jetting head according to claim 14 ,
wherein the flow channel substrate is further formed with a third flow channel through which a third color liquid flows,
the pressure chambers further include a third pressure chamber which belongs to the third flow channel and which is aligned with the first pressure chamber and the second pressure chamber in the arrangement direction,
the dummy pressure chambers further include a third dummy pressure chamber adjacent to the third pressure chamber in the arrangement direction,
the temperature sensor further includes a third temperature sensor arranged at a position facing the third dummy pressure chamber, and
the first temperature sensor, the second temperature sensor, and the third temperature sensor are arranged in the arrangement direction at regular intervals.
16. The liquid jetting head according to claim 1 , wherein thickness of the temperature sensor is smaller than thickness of the piezoelectric body.