Liquid ejection head and ink jet printer

Patent metadata

Field	Value
Publication number	US-10179451-B2
Application number	US-201615547247-A
Country	US
Kind code	B2
Filing date	Jan 28, 2016
Priority date	Jan 30, 2015
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

A liquid ejection head includes an ejection port to eject liquid, a pressure chamber communicating with the ejection port, and a piezoelectric element to pressurize the pressure chamber and eject from the ejection port, the liquid stored in the pressure chamber. At least a part of a wall portion defining the pressure chamber includes a portion where vibration characteristics are different between a pressurized state in which the pressure chamber is pressurized by the piezoelectric element and a depressurized state in which the pressure chamber is depressurized by ejecting the liquid from the ejection port and stopping pressurization to the pressure chamber, and the portion having different vibration characteristics is adapted to reduce pressure fluctuation in the pressure chamber in the depressurized state.

First claim

The invention claimed is:

1. A liquid ejection head comprising:
an ejection port configured to eject liquid;
a pressure chamber communicating with the ejection port; and
a piezoelectric element configured to pressurize the pressure chamber and eject, from the ejection port, the liquid stored in the pressure chamber, wherein
a lower wall of the pressure chamber includes a portion where vibration characteristics are different between a pressurized state in which the pressure chamber is pressurized by the piezoelectric element and a depressurized state in which the pressure chamber is depressurized by ejecting the liquid from the ejection port and stopping pressurization to the pressure chamber,
the portion having different vibration characteristics is configured to reduce pressure fluctuation in the pressure chamber in the depressurized state,
the portion having different vibration characteristics includes a first layer and a second layer having rigidity higher than rigidity of the first layer, the second layer being formed separately from the first layer so as to form a gap in a space with the first layer,
the first layer and the second layer are sequentially arranged from the pressure chamber side,
the first layer is deformed together with the second layer in a state of contacting the second layer in the pressurized state, and
the first layer is deformed independently from the second layer in the depressurized state.

2. The liquid ejection head according to claim 1 , wherein the part of the wall of the pressure chamber is located on a wall portion different from a side where the piezoelectric element is arranged.

3. The liquid ejection head according to claim 2 , wherein the portion having different vibration characteristics has rigidity in the depressurized state lower than rigidity in the pressurized state.

4. The liquid ejection head according to claim 2 , wherein the portion having different vibration characteristic is formed by providing a plurality of groove portions opened toward the pressure chamber side on at least a part of the wall portion defining the pressure chamber.

5. The liquid ejection head according to claim 2 , wherein
the first layer is made of a porous member.

6. The liquid ejection head according to claim 2 , wherein
the first layer is formed of a stress control film configured to apply tensile stress to the portion having different vibration characteristics.

7. The liquid ejection head according to claim 2 , wherein
the first layer is formed of a stress control film configured to apply compressive stress to the portion having different vibration characteristics.

8. The liquid ejection head according to claim 1 , wherein the portion having different vibration characteristics has rigidity in the depressurized state lower than rigidity in the pressurized state.

9. The liquid ejection head according to claim 1 , wherein the gap is formed of an air layer filled with air.

10. The liquid ejection head according to claim 1 , wherein the second layer has a protrusion protruding toward the pressure chamber, and the first layer covers the protrusion so as to form a gap in a space with the protrusion.

11. The liquid ejection head according to claim 1 , wherein the first layer is made of resin, silicon, or a metal film.

12. The liquid ejection head according to claim 1 , wherein the portion having different vibration characteristic is formed by providing a plurality of groove portions opened toward the pressure chamber side on at least a part of the wall portion defining the pressure chamber.

13. The liquid ejection head according to claim 1 , wherein
the first layer is made of a porous member.

14. The liquid ejection head according to claim 1 , wherein
the first layer is formed of a stress control film configured to apply tensile stress to the portion having different vibration characteristics.

15. The liquid ejection head according to claim 1 , wherein
the first layer is formed of a stress control film configured to apply compressive stress to the portion having different vibration characteristics.

16. An ink jet printer including the liquid ejection head according to claim 1 and configured to perform printing by ejecting the liquid toward a recording medium from the liquid ejection head.

Assignees

• Konica Minolta Inc

Inventors

• Matsuda Shinya

Classifications

• B41J2/1433

  Structure of nozzle plates · CPC title

• B41J2/055 Primary

  Devices for absorbing or preventing back-pressure · CPC title

• B41J2/1623

  bonding and adhesion · CPC title

• B41J2/1629

  wet etching · CPC title

• B41J2/16

  Production of nozzles · CPC title