JPH10250072A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet head by integrally adhering constituting members without using adhesive. SOLUTION: The ink jet head comprises a channel unit 12 having an ink pressurizing chamber 30, an ink supply passage 28, an ink supply chamber 32 and an ink channel 33 made of a nozzle 24, and an ink pressurizing piezoelectric actuator 14 provided on the surface of the unit 12. In this case, the unit 12 is constituted by laminating a plurality of ceramic layers 16, 18, 20, 22 each having a region of part of the channel 33. And, the layers 16, 18, 20, 22 of the unit 12 are integrally adhered to the actuator 14 by heating in the case of baking the actuator 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet head for recording an image by ejecting ink droplets from nozzles in accordance with an image signal and attaching the ink droplets to a recording medium such as recording paper.

[0002]

2. Description of the Related Art Conventionally, as an ink jet head, an ink pressurizing chamber for pressurizing stored ink, an ink supply chamber for supplying ink to the ink pressurizing chamber via an ink supply path, and an ink pressurizing chamber. 2. Description of the Related Art There are known nozzles having a nozzle for discharging pressurized ink and a piezoelectric actuator for pressurizing ink in an ink pressurizing chamber. This type of ink-jet head is usually formed by precisely positioning a plurality of members with an adhesive to form an ink pressurizing chamber, an ink supply chamber, a nozzle, and the like. In addition, for the piezoelectric actuator, a single fired piezoelectric plate is bonded and fixed to the support substrate, and then divided by dicing with a dicing saw in order to provide a plurality of arranged ink pressurizing chambers. Then, there is a method of forming a plurality of piezoelectric actuators.

[0003]

However, in an ink jet head which assembles components by fixing them with an adhesive,
Man-hours for applying the adhesive are required according to the number of constituent members, and the assembling process becomes longer accordingly. Also, it takes time to cut out the piezoelectric actuators one by one with a dicing saw. Therefore, there is a problem that an ink jet head requiring such an assembling and manufacturing process has a low mass productivity and a high production cost.

[0004]

In order to solve the above problems, an ink jet head according to the present invention has an ink pressurizing chamber for pressurizing stored ink, and the ink pressurizing chamber is connected to the ink pressurizing chamber via an ink supply path. Supply ink supply chamber,
A flow path unit including an ink flow path formed of nozzles for discharging ink pressurized in the ink pressurization chamber; and an ink pressurizing piezoelectric provided on the flow path unit in correspondence with the ink pressurization chamber. And an actuator, wherein the flow path unit is formed by stacking a plurality of members each having a region that forms a part of the ink flow path, and each configuration of the flow path unit is heated by firing the piezoelectric actuator. The member and the piezoelectric actuator are integrally bonded.

In this ink jet head, the flow path unit may be formed by laminating a plurality of ceramic layers, and each of the ceramic layers may be fired by the heating and adhered integrally.

The flow path unit is composed of an ink pressurizing chamber forming member made of a metal material and a substrate having the ink supply chamber, the ink supply path, and the nozzle. The substrate and the substrate may be bonded together by diffusion bonding by the heating.

[0007]

According to the ink jet head of the present invention, the constituent members of the ink pressurizing chamber, the ink supply chamber, the ink supply path, and the flow path unit having the nozzle are integrally bonded together with the firing of the piezoelectric actuator. Further, the piezoelectric actuator is also integrally bonded to the channel unit by firing. This eliminates the step of applying an adhesive at the time of assembling the ink jet head, and furthermore, the components of the flow path unit and the piezoelectric actuator can be integrally bonded in one heating step, thereby simplifying the assembling step. . As a result, the mass productivity of the head is improved, and the production cost can be reduced.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 show an inkjet head 10 according to a first embodiment. This head 10
Has a channel unit 12 and a piezoelectric actuator 14. The flow channel unit 12 has four ceramic layers 16, 18, separated by dotted lines in the cross section shown in FIGS.
20 and 22 are laminated, and these are integrally bonded by firing. The flow path unit 12 includes an ink flow path 3 including a nozzle 24, a nozzle communication hole 26, an ink supply path 28, an ink pressurizing chamber 30, and an ink supply chamber 32.
Three.

The above ceramic layers 16, 18, 20, 2
Reference numerals 2 each have an area forming a part of the ink flow path 33. That is, a plurality of the funnel-shaped nozzles 24 are formed in the first ceramic layer 16, and are arranged in a zigzag pattern on both sides of the ink supply chamber 32 in a staggered manner as shown in FIG. 1. In order to stabilize the ink meniscus in the nozzle 24, it is preferable to perform a water-repellent treatment on the lower surface of the first ceramic layer 16.

The nozzle communication holes 26 are formed concentrically in the second ceramic layer 18 so as to communicate with the respective nozzles 24. In the second ceramic layer 18, the ink supply chamber 32 extending in the longitudinal direction at the center of the head 10, the ink supply chamber 32 and the nozzle communication holes 2 are provided.
6 are formed, and the ink supply path 28 is formed to connect the ink supply passages 6 and 6 to each other. One end (not shown) of the ink supply chamber 32 is closed, and the other end 38 is connected to an ink tank (not shown).

The ink pressurizing chamber 30 is formed in the third ceramic layer 20 and communicates with each nozzle communication hole 26 and the ink supply path 28. The fourth ceramic layer 22 covers the ink pressurizing chamber 30 so as to form one wall, and functions as a diaphragm. A common electrode 34 made of a conductive metal layer is formed on the upper surface of the fourth ceramic layer 22.

The above-mentioned substantially disk-shaped piezoelectric actuator 14
Is the surface of the channel unit 12 and the common electrode 34
The ink pressure chambers 30 are provided on the upper side respectively. In addition, individual electrodes 36 made of a conductive metal layer are provided above the piezoelectric actuator 14.

Next, the manufacturing process of the ink jet head 10 having the above-described configuration will be described. Each of the ceramic layers 16, 18, 20, and 22 is made of a known ceramic material (for example, zirconium oxide or aluminum oxide), and is individually processed in a green sheet state before firing.

As shown in FIG. 4, an excimer laser beam is applied to a green sheet 40 serving as the first ceramic layer 16 through a mask 44 having a plurality of openings 42, and each nozzle 24 is formed by ablation. I do.

As shown in FIG. 5, the green sheet 46 serving as the second ceramic layer 18 is formed by punching with a super hard die 48 so that the nozzle communication holes 2 are formed.
6. Form a through hole or a groove to be the ink supply path 28 and the ink supply chamber 32. In order to form the nozzle communication holes 26 and the ink supply passages 28 on both sides of the ink supply passage 32, the carbide die 48 or the green sheet 46 may be rotated to perform two punchings, or one punching operation. The mold shape of the super hard mold 48 may be formed so as to be able to be formed by the above.

As shown in FIG. 6, a rectangular through hole which becomes the ink pressurizing chamber 30 is similarly formed by punching a green sheet 50 which becomes the third ceramic layer 20 with a super hard mold 52. I do.

As shown in FIG. 7, a common electrode 3 is formed on the upper surface of a green sheet 54 serving as the fourth ceramic layer 22.
An electrode material, for example, Ag-Pd paste 4 is applied to a uniform thickness by a screen printing method or the like, and a well-known paste-like piezoelectric material (for example, PZT) is applied thereon by a screen printing method or the like. 14 is formed.

Each green sheet 4 processed as described above
The layers 0, 46, 50, and 54 are laminated in this order while being accurately positioned by a jig, and after lamination, pressure is applied to each sheet to bring the sheets into close contact. Then, the laminate is placed in a heating furnace and fired. The firing conditions are, for example, about 1200 ° C.
The temperature was raised over 2 hours until the temperature was maintained at that temperature for 1.5 hours, followed by natural cooling in a furnace. As a result, the ceramic layers 16, 18, 20, 22 and the piezoelectric actuator 14 are baked and bonded together.

On the fired body taken out of the heating furnace, an individual electrode 36 is formed on the upper part of each piezoelectric actuator 14 by Ag-P.
It is formed by screen printing of d paste or Au sputtering. Then, a high voltage is applied between the common electrode 34 and the individual electrode 36 at a high temperature to polarize the piezoelectric actuator 14.

As described above, in the ink jet head 10 of the present embodiment, the plurality of ceramic layers 16, 18, 20, 22 and the piezoelectric actuator 14 constituting the flow path unit 12 are integrally formed simultaneously with firing without using an adhesive. Glued. Therefore, the inkjet head 1
No assembly process is required at the time of assembling, and the baking and bonding of each member can be performed simultaneously in a single heating process, which simplifies the head assembly and manufacturing process, and enables mass production. And production costs can be reduced.

In the ink jet head 10, ink supplied from an ink tank (not shown) to the ink supply chamber 32 is supplied to the ink pressurizing chamber 30 via the ink supply path 28.
It is accommodated in the nozzle communication hole 26 and the nozzle 24. In this state, when a driving voltage is applied between the individual electrode 36 and the common electrode 324 from the driver circuit according to the image signal, the piezoelectric actuator 14 is instantaneously contracted and deformed in the radial direction. Due to this deformation, the fourth ceramic layer 22 is curvedly displaced in a convex shape toward the ink pressurizing chamber 30, as indicated by a dotted line 58 in FIG. The ink pressurized by this displacement is ejected from the nozzles 24 as ink droplets, and adheres to a recording medium (not shown) to record an image. When the voltage application is released, the walls of the piezoelectric actuator 14 and the ink pressurizing chamber 30 return to the original state, and the ink supply chamber 3
Ink is supplied to the ink pressurizing chamber 30 from 2.

It should be noted that the number of laminated ceramic layers constituting the flow path unit 12 of the ink jet head 10 described above is not limited to four, but can be variously changed.

Next, an ink jet head 60 according to a second embodiment will be described with reference to FIG. FIG. 8 is a partial cross-sectional view of the head 60 in the same direction as FIG. 2 showing the inkjet head 10, and its plan view is almost the same as FIG.

As shown in FIG. 8, each of the flow path units 12 of the ink jet head 60 is composed of a substrate 62 made of a metal material and an ink pressurizing chamber forming member 64 laminated so as to cover the substrate. The substrate 62 is made of, for example, Ni.
Formed by electroforming, the nozzle 24, the nozzle communication hole 26,
An ink supply chamber 32 and an ink supply path 28 connecting the nozzle communication hole 26 and the ink supply chamber 32 are provided.
The ink pressurizing chamber forming member 64 is formed with a hemispherical ink pressurizing chamber 30 communicating with the nozzle communication hole 26 and the ink supply path 28 by, for example, embossing a Ni thin plate. The individual electrodes 36 are provided above the ink pressurizing chamber 30.
Is provided. In this embodiment, since the ink pressurizing chamber forming member 64 itself has conductivity, it can be used as a common electrode.

The substrate 62 and the ink supply chamber forming member 64
Means that when the piezoelectric actuator 14 is heated at the time of firing, the piezoelectric actuator 14 is bonded by diffusion bonding at its contact surface. Therefore, also in the present embodiment, as in the case of the above-described inkjet head 10, the substrate 62, the ink pressurizing chamber forming material 64, and the piezoelectric actuator 14 can be bonded in a single heating step without using an adhesive. Can be simplified, the mass productivity can be improved, and the production cost can be reduced.

In the ink jet head 60, when a drive voltage is applied between the individual electrode 36 and the ink pressurizing chamber forming material 64 from the driver circuit, the piezoelectric actuator 14 contracts and deforms in the direction of the arrow. Due to this deformation, the inner surface of the ink pressurizing chamber 30 is displaced to the state shown by the dotted line, the ink in the ink pressurizing chamber 30 is pressurized, and ink droplets are ejected from the nozzles 24.

The ink pressurizing chamber forming material 64 is not limited to the shape shown in FIG. 8, but can be variously modified. For example, the third and fourth ceramic layers 20 of the ink jet head 10 can be used. , 22 may be integrally formed.

In the first embodiment, the individual electrodes are provided after the firing and the polarization of the piezoelectric actuator is performed. However, the electrode material for the individual electrodes is screen-printed or the like before the firing. In this case, the individual electrodes can be joined together at the same time, and the manufacturing process of the head can be simplified. In this case, after a certain period of time elapses during sintering and the crystallization of the piezoelectric material proceeds, a high voltage is applied between the common electrode 34 and the individual electrodes 36 to polarize the piezoelectric actuator. Can also. In this way, the polarization of the piezoelectric actuator can be performed in one step, and the manufacturing process of the head can be further simplified.

[Brief description of the drawings]

FIG. 1 is a partial plan view of an inkjet head according to a first embodiment.

FIG. 2 is a cross-sectional view of the head shown in FIG. 1, taken along the line II-II.

FIG. 3 is a sectional view of the head shown in FIG. 1, taken along line III-III.

FIG. 4 is a view showing a method of processing a first ceramic layer of the flow channel unit.

FIG. 5 is a view showing a method for processing a second ceramic layer of the flow channel unit.

FIG. 6 is a diagram illustrating a method of processing a third ceramic layer of the flow channel unit.

FIG. 7 is a diagram illustrating a method of forming a fourth ceramic layer and a piezoelectric actuator of the flow channel unit.

FIG. 8 is a partial cross-sectional view of an inkjet head according to a second embodiment.

[Explanation of symbols]

10, 60: inkjet head, 12: flow path unit, 16, 18, 20, 22: ceramic layer, 14: piezoelectric actuator, 24: nozzle, 28: ink supply path, 30: ink pressurizing chamber, 32: ink supply Room, 33 ...
Ink flow path, 62: substrate, 64: ink pressurizing chamber forming member.

Claims (3)

[Claims] 1. An ink pressurizing chamber for pressurizing stored ink, an ink supply chamber for supplying ink to the ink pressurizing chamber via an ink supply path, and an ink pressurizing chamber that pressurizes the ink pressurized in the ink pressurizing chamber. A flow path unit including an ink flow path composed of a nozzle for discharging, and a piezoelectric actuator for ink pressurization provided on the flow path unit in correspondence with the ink pressurization chamber; An ink-jet ink comprising a plurality of members each having an area forming a part of a path, and each of the constituent members of the flow path unit and the piezoelectric actuator are integrally bonded by heating when firing the piezoelectric actuator; head. 2. The ink jet head according to claim 1, wherein the flow path unit is formed by laminating a plurality of ceramic layers, and each of the ceramic layers is baked by the heating and adhered integrally. 3. The ink pressure chamber forming member made of a metallic material, and the flow path unit includes a substrate provided with the ink supply chamber, the ink supply path, and the nozzle. The ink jet head according to claim 1, wherein the substrate and the substrate are bonded together by diffusion bonding by the heating.