Liquid jetting head and liquid jetting apparatus

Abstract

A liquid droplet jetting head, having: a plurality of dividing walls to divide a plurality of flow channels, wherein at least a portion of the dividing wall is formed with a piezoelectric element; a flow path having a rectangular tubular from formed by an upper wall to close an upper surface of the flow path along an array direction of the plurality of the flow paths, and a lower wall to close a lower surface of the flow path; a nozzle to jet liquid in the flow path as the liquid droplet; and two driving electrodes formed independently on each wall surface of the dividing wall in a longitudinal direction of the flow path having the rectangular tubular form, wherein the nozzle is formed on either the upper wall or the lower wall.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a schematic structure of an inkjet recording apparatus.

FIG. 2 is an exploded perspective view of a shear mode type inkjet head representing an embodiment of the liquid jetting head.

FIG. 3 (a) is a cross-sectional view of the head in FIG. 2 in which a wiring substrate and a manifold are provided.

FIG. 3 (b) is a perspective view of a cross section D-D in FIG. 2.

FIG. 4 (a) is a view showing operation of the head to jet the ink droplet.

FIG. 4 (b) is a view showing operation of the head to jet the ink droplet.

FIG. 4 (c) is a view showing operation of the head to jet the ink droplet.

FIG. 5 (a) is a drawing to describe time shearing operation of the head.

FIG. 5 (b) is a drawing to describe time shearing operation of the head.

FIG. 5 (c) is a drawing to describe time shearing operation of the head.

FIG. 6 is a timing chart of driving signals applied to ink flow paths in each of groups a, b and c.

FIG. 7 is a timing chart of driving signals in case only positive voltage is used.

FIG. 8 is a timing chart of driving signals applied to ink flow paths in each of groups a, b and c.

FIG. 9 is a timing chart of driving signals in case only positive voltage is used.

Claims

1. A liquid droplet jetting head, comprising: dividing walls to form a plurality of flow paths in a shape of rectangular tubular having an upper wall to close an upper surface of the flow path and a lower wall to close a lower surface of the flow path wherein at least a portion of each dividing wall is formed with a piezoelectric element;nozzles to jet liquid in the flow paths as a liquid droplet; andtwo driving electrodes independently formed on each wall surface of the dividing walls in a longitudinal direction of the flow paths in the shape of rectangular tubular;wherein the nozzles are formed on either the upper wall or the lower wall.

2. The liquid droplet jetting head of claim 1, wherein driving signals are applied to each of two driving electrodes independently.

3. The liquid droplet jetting head of claim 2, wherein the diving signals to be applied to two driving electrodes are rectangular waves having consistent inflation and deflation voltages and a time difference Δt between falling edges of the driving signals satisfies a formula below. 0≦Δt≦2 AL

4. The liquid droplet jetting head of claim 2, wherein an amount of the liquid droplet is varied by changing a voltage of the driving signal while maintaining a consistent flying speed of the liquid droplet.

5. The liquid droplet jetting head of claim 1, wherein one nozzle is disposed at a position corresponding to middle of two driving electrodes.

6. The liquid droplet jetting head of claim 5, wherein two driving electrodes are symmetrically disposed centering around a position corresponding to the nozzle.

7. A liquid droplet jetting apparatus, comprising: the liquid droplet jetting head of claim 1.

8. A liquid droplet jetting apparatus, comprising: the liquid droplet jetting head of claim 2.

9. A liquid droplet jetting apparatus, comprising: the liquid droplet jetting head of claim 3.

10. A liquid droplet jetting apparatus, comprising: the liquid droplet jetting head of claim 4.

11. A liquid droplet jetting apparatus, comprising: the liquid droplet jetting head of claim 5.

12. A liquid droplet jetting apparatus, comprising: the liquid droplet jetting head of claim 6.