JP3211508B2 - Ink jet head and method of manufacturing the same - Google Patents

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 and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a drop-on-demand type ink jet head, for example, the volume of an ink flow path is changed by deformation of a piezoelectric ceramic as an ink ejection energy generating element, so that when the volume decreases, the ink flow in the ink flow path is reduced. In some cases, ink is ejected from a nozzle as droplets, and ink is introduced from an ink inlet into a groove when the volume is increased. Then, desired characters and images are formed on a paper surface or the like facing the inkjet head by ejecting ink droplets from the inkjet head at a required position in accordance with required print data.

[0003] As this kind of ink jet head,
For example, JP-A-63-247051 and JP-A-63-27051
There are those described in JP-A-252750 and JP-A-2-150355. Such a conventional example will be described with reference to the drawings.

As shown in FIG. 6, an ink jet head 1 includes a piezoelectric ceramic plate 2 and a cover plate 3.
, A nozzle plate 31 and a substrate 41.

The piezoelectric ceramic plate 2
Has a plurality of grooves 8 formed therein. The side wall 11 serving as the side surface of the groove 8 is polarized in the direction of the arrow 5.
The grooves 8 are of the same depth and are parallel. The depth of the grooves 8 is determined by the one end face 15 of the piezoelectric ceramic plate 2.
The shallow groove 16 is formed in the vicinity of the one end face 15. On the inner surface of the groove 8, metal electrodes 13 are formed on the upper halves of both sides by sputtering or the like. On the inner surface of the shallow groove 16, a metal electrode 9 is formed on the side and bottom surfaces thereof by sputtering or the like. Thus, the metal electrodes 13 formed on both side surfaces of the groove 8 are electrically connected by the metal electrodes 9 formed in the shallow groove 16.

Next, the cover plate 3 is made of a glass material,
It is formed from a ceramic material or a resin material. The cover plate 3 is provided with an ink inlet 21 and a manifold 22 by grinding or cutting.
Are formed. Then, the surface of the piezoelectric ceramic plate 2 on the processing side of the groove 8 and the surface of the cover plate 3 on the processing side of the manifold 22 are bonded with an epoxy-based adhesive or the like. Accordingly, a plurality of ink flow paths 12 (FIG. 7) are formed in the inkjet head 1 so as to cover the upper surface of the groove 8 and have a space therebetween in the horizontal direction. The ink flow path 12 has an elongated shape with a rectangular cross section.
The inside is filled with ink.

[0007] A substrate 41 is bonded to the surface of the piezoelectric ceramic plate 2 opposite to the processing side of the groove 8 with an epoxy-based adhesive or the like. The substrate 41
The conductive layer pattern 42 is formed at a position corresponding to the position of each ink flow path 12. The conductive layer pattern 42 and the metal electrode 9 on the bottom surface of the shallow groove 16 are connected by a conductive wire 43 by well-known wire bonding.

Further, a nozzle plate 31 having nozzles 32 provided at positions corresponding to the positions of the ink flow paths 12 is bonded to the end faces 4 of the piezoelectric ceramic plate 2 and the cover plate 3. This nozzle plate 31
Polyalkylene (eg, ethylene) terephthalate, polyimide, polyetherimide, polyetherketone,
The nozzle 32 is formed by punching a sheet of a resin material such as polyether sulfone, polycarbonate, or cellulose acetate by laser processing or the like. FIG. 7 is a sectional view showing the vicinity of the nozzle plate 31 of the conventional ink jet head 1.

[0009]

However, in the above-described ink-jet head 1, as shown in FIG. 7, the nozzle plate 31 and the cover plate 3 or the piezoelectric ceramic plate 2 form the ink flow path 12 on the nozzle plate 31 side. Has a rectangular shape 7, so that air that has entered the ink flow path 12 is trapped in the rectangular shape 7 portion, air does not escape from the nozzles 32, ink ejection is poor, and print quality is reduced. There was a problem of doing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an ink jet head having excellent print quality and a method of manufacturing the same.

[0011]

Means for Solving the Problems] According to claim 1 of the present invention in order to achieve this object, a nozzle plate ink discharge port is formed, an ink flow path communicating with Lee ink discharge port of the nozzle plate Formed in the ink flow path.
In the inkjet head having an actuator portion provided with an electrode to give an injection energy to ink, the Lee
To protect the electrodes in the ink channel from ink.
A resin layer was formed to cover the electrode in the ink flow path, and a tapered resin layer integrally formed with the resin layer was formed in a rectangular portion formed by the ink flow path and the nozzle plate. It is characterized by the following.

[0012] In claim 2, the nozzle plate ink discharge port is formed, in the manufacturing method of the ink-jet head having an actuator unit for an ink flow path is formed that communicates with the Lee ink ejection port of the nozzle plates, A step of supplying a resin into the ink flow path, a step of bonding a plate not provided with the ink discharge ports serving as the nozzle plate to the actuator section, and heating the actuator section and the plate; The method is characterized by comprising a step of depositing the resin in the ink flow path on the plate side and a step of forming an ink discharge port in the plate.

[0013] According to claim 3, the nozzle plate ink discharge port is formed, an ink flow path communicating with Lee ink discharge port of the nozzle plates are formed on the ink flow path
A method of manufacturing an ink jet head having an actuator section having an electrode for applying ejection energy to ink, wherein the electrode in the ink flow path is protected from ink.
Supplying a resin covering the electrodes into the ink flow path , bonding the nozzle plate to the actuator section, heating the actuator section and the nozzle plate, The resin
Flowing and depositing on the nozzle plate side;
Removing the resin in the ink discharge ports of the nozzle plate to communicate the ink discharge ports with the ink flow paths.

[0014]

According to the ink jet head of the present invention having the above-described structure, a rectangular portion formed by the nozzle plate of the actuator portion is provided with a resin layer for protecting the electrode.
Since the tapered resin layer of the body is formed, even if air enters the ink flow path, the air is easily discharged.

In the method of manufacturing an ink jet head according to the present invention, a plate which is not provided with the ink discharge ports serving as the nozzle plate is adhered to the actuator section, the actuator section and the plate are heated, and the ink plate is heated. Resin supplied into the flow path is deposited on the plate side, and a communication surface between the ink discharge port and the ink flow path is curved by the resin. And
An ink ejection port is formed in the plate.

According to a third aspect of the present invention, the nozzle plate is bonded to the actuator section, and the actuator section and the nozzle plate are heated to protect the electrodes in the ink flow path.
The flow of the resin is carried out and deposited on the nozzle plate side, and the communication surface between the ink discharge port and the ink flow path is curved by the resin. Then, the resin in the ink discharge port of the nozzle plate is removed, and the ink discharge port and the ink flow path are communicated.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. For convenience, the same parts and equivalent parts as in the conventional example are denoted by the same reference numerals, and description thereof will be omitted.

The ink jet head of this embodiment comprises a piezoelectric ceramic plate 2 (FIG. 6), a cover plate 3 (FIG. 6), a nozzle plate 31 (FIG. 6), and a substrate 41 (FIG. 6) as in the prior art. Have been. A plurality of grooves 8 (FIG. 6) separated by side walls 11 (FIG. 6) are formed in the piezoelectric ceramic plate 2, and these side walls 11 are polarized in the direction of arrow 5 shown in FIG. The metal electrodes 13 formed on the upper half of both sides of the groove 8
(FIG. 6) shows the metal electrode 9 formed in the shallow groove 16 (FIG. 6).
(FIG. 6).

Then, the surface of the piezoelectric ceramic plate 2 on the processing side of the groove 8 and the surface of the cover plate 3 on the processing side of the manifold 22 are adhered to form a plurality of ink flow paths 12 as shown in FIG. I have.

A nozzle plate 31 provided with a nozzle 32 at a position corresponding to the position of each ink flow path 12 is adhered to the end surface 4 (FIG. 6) of the piezoelectric ceramic plate 2 and the cover plate 3.

Here, a method of manufacturing the piezoelectric ceramic plate 2 will be described.

A piezoelectric ceramic sheet is formed from the piezoelectric ceramic powder by a sheet forming method and sintered to obtain a piezoelectric ceramic sintered body. Next, a polarization process is performed on the piezoelectric ceramic sintered body to form a piezoelectric ceramic element. The piezoelectric ceramic element is cut by a thin disk-shaped diamond blade to form a groove 8.
Is formed, and the metal electrode 1 is formed by sputtering or the like.
3, 9 are formed. Thus, the piezoelectric ceramic plate 2 is formed.

Next, the piezoelectric ceramic plate 2
Then, a film of an epoxy resin (Epotech 377, manufactured by Epoxy Technology Co., Ltd., viscosity: 500 cps) for protecting the metal electrodes 13 and 9 from ink is formed by spin coating.

First, as shown in FIG. 2, the center of the piezoelectric ceramic plate 2 is set on a rotary table 71 on which a work is set.
It is installed at a position 100 mm from the center of rotation. At this time,
The end surface 4 of the piezoelectric ceramic plate 2 is arranged so as to face outward from the center of the turntable 71. Then, the epoxy resin 72 is dropped from the chemical solution supply nozzle 70 onto the piezoelectric ceramic plate 2 at a dropping rate of 1 cc / sec while rotating the rotary table 71 at a rotation speed of 500 rpm. After that, the rotation speed is increased at an acceleration of 150 rpm / sec, and the rotation speed is maintained at 2000 rpm for 10 seconds. Leave in. By appropriately selecting the viscosity of the resin, the distance from the rotation center, the rotational acceleration, and the maximum rotational speed, the amount of the residual resin can be easily controlled.

In addition to the epoxy resin, a phenol resin, a phenoxy resin and the like can be used as the resin, but an epoxy resin is more preferable from the viewpoint of ink resistance.

Next, the surface of the alumina ceramics cover plate 3 on which the ink inlet 21 (see FIG. 6) and the manifold 22 (see FIG. 6) are formed by grinding and cutting, is provided with a piezoelectric material. The surface of the ceramic plate 2 on the processing side of the groove 8 is temporarily bonded.

Here, the cover plate 3 may be made of a ceramic material such as zirconia ceramics or piezoelectric ceramics, a glass material, or a resin material, in addition to alumina ceramics.

Then, a polyimide film serving as the nozzle plate 31 is set on the end faces 4 (see FIG. 6) of the piezoelectric ceramic plate 2 and the cover plate 3.

Then, the piezoelectric ceramic plate 2, the cover plate 3, and the polyimide film in a state of being temporarily bonded are temporarily bonded in a heating oven with the polyimide film on the lower side.

Then, it is heated to 150 ° C. and kept for 60 minutes. As a result, the piezoelectric ceramic plate 2, the cover plate 3, and the polyimide film serving as the nozzle plate 31 are firmly adhered to each other, and the viscosity of the epoxy resin remaining in the groove 8 temporarily decreases in the initial stage of heating. On the polyimide film side by gravity,
It deposits in a spherical shape due to surface tension and is completely cured at the end of heating.

Next, nozzles 32 are formed by excimer laser or the like at positions corresponding to the positions of the respective ink flow paths 12 on the polyimide film to be the nozzle plate 31.

As a result, as shown in FIG.
An ink jet head is formed in which a tapered resin layer 73 is formed at the boundary between the ink flow path 2 and the ink flow path 12.

The nozzle plate 31 is made of liquid crystal polymer, polyacetal, polyphenylene sulfide, polyphenylsulfone, polyphthalamide, polyethylene terephthalate, polyetherimide, polyether ketone, polyether sulfone, polycarbonate, cellulose acetate, in addition to polyimide. And the like.
In addition, not only a film-shaped plate but also a plate manufactured by injection molding can be used.

A substrate 41 (see FIG. 6) is bonded to the surface of the piezoelectric ceramic plate 2 opposite to the processing side of the groove 8 with an epoxy-based adhesive or the like.
On the substrate 41, a conductive layer pattern 42 (see FIG. 6) is formed at a position corresponding to the position of each ink flow path 12. The conductive layer pattern 42 and the metal electrode 9 on the bottom surface of the shallow groove 16 are connected by a wire 43 (see FIG. 6) by wire bonding.

Next, the configuration of the control unit will be described with reference to FIG. 3 showing a block diagram of the control unit. The conductive layer patterns 42 formed on the substrate 41 are individually connected to the LSI chip 51. Further, the clock line 52, the data line 53, the voltage line 54 and the ground line 55 are also LS.
It is connected to the I chip 51. The LSI chip 51
Based on the continuous clock pulse supplied from the clock line 52, it is determined which nozzle 32 should eject the ink droplet according to the data appearing on the data line 53. Then, the LSI chip 51 applies the voltage V of the voltage line 54 to the pattern 42 of the conductive layer that is electrically connected to the metal electrode 13 in the ink flow path 12 to be driven.
Further, the LSI chip 51 applies a voltage of 0 V of the ground line 55 to the conductive layer pattern 42 that is connected to the metal electrode 13 other than the ink flow path 12 to be driven.

Next, the operation of the ink jet head will be described with reference to FIGS.

It is determined that the LSI chip 51 will eject ink from the ink flow path 12b of the ink jet head according to required data. Then, the metal electrode 13e
And 13f, a positive drive voltage V is applied, and the metal electrode 13
d and 13g are grounded. Then, as shown in FIG. 5, a driving electric field in the direction of arrow 14b is generated on the side wall 11b, and a driving electric field in the direction of arrow 14c is generated on the side wall 11c. Then, since the driving electric field directions 14b and 14c are orthogonal to the polarization direction 5, the side walls 11b and 11c are
In this case, the ink flow path 12
Deforms rapidly toward the inside of b. Due to this deformation, the volume of the ink flow path 12b decreases, the ink pressure rapidly increases, a pressure wave is generated, and ink droplets are ejected from the nozzle 32 (FIG. 1) communicating with the ink flow path 12b. When the application of the drive voltage V is stopped, the side walls 11b and 11c
Returns to the position before the deformation (see FIG. 4).
The ink pressure in b decreases. Then, the ink inlet 2
1 (see FIG. 6), ink is supplied into the ink flow path 12b through the manifold 22 (see FIG. 6).

In order to improve the efficiency of ink ejection, the direction of the polarization 5 is usually reversed, and a positive voltage is applied to first deform the side walls 11b and 11c away from each other. By stopping the application of the voltage, the side walls 11b and 11c may return to the positions before the deformation and eject the ink droplets.

In the case of the conventional ink jet head as shown in FIG. 7, the air trapped in the ink flow path 12 is not discharged, and the ink jetting becomes defective. When an ink ejection test was performed using ink using tripropylene glycol monomethyl ether as a solvent, even if air entered the ink flow path 12, the air was easily discharged because the tapered resin layer 73 was formed. It was ejected and good ink ejection was performed. Further, in the case of the conventional ink jet head shown in FIG. 7, a driving voltage of 28 V was required to obtain stable ink jetting, but in the case of the ink jet head of this embodiment, stable ink jetting was performed at 22 V. Was able to do. Furthermore, even when the solvent of the ink was highly corrosive tripropylene glycol monomethyl ether, the resin layer 73 was not corroded in the case of an epoxy resin.

In this embodiment, the tapered resin layer 73 is formed by using the surplus portions of the protective films of the metal electrode 13 and the metal electrode 9 formed by the spin coating method. The number of steps for forming the resin layer 73 is reduced.

In this embodiment, the amount of the resin present in the ink flow path 12 is controlled by the spin coating method, but may be controlled by the dipping / pulling method.

Further, in this embodiment, a polyimide film having no nozzle 32 formed thereon is temporarily bonded to the piezoelectric ceramic plate 2 and the cover plate 3 and subjected to a heat treatment, so that the piezoelectric ceramic plate 2 and the cover The polyimide film to be the plate 3 and the nozzle plate 31 is firmly adhered and the epoxy resin is deposited on the polyimide film side. However, heat treatment is performed using the nozzle plate 31 in which the nozzle 32 is formed. Alternatively, an epoxy resin may be deposited on the nozzle plate 31 side. In this case, after the heat treatment, the nozzle 32
The epoxy resin in the inside is removed by a laser or the like, and the ink flow path 12 and the nozzle 32 are communicated.

Further, in this embodiment, the nozzle plate 31
Is heated downward to deposit the resin by gravity, but the resin may be deposited not in the nozzle plate 31 but in a diagonally downward direction. However, in this case, the position of the nozzle 32 is provided not above the center but above the ink flow path 12. Alternatively, the resin may be deposited by centrifugal force with the nozzle plate 31 horizontal.

[0044]

As is apparent from the above description, according to the ink jet head of the present invention, the communication surface between the ink discharge port and the ink flow path is made of a resin for protecting electrodes.
Since the resin is formed into a tapered shape, even if air enters the ink flow path, the air is easily discharged, the printing quality is excellent, the ink flow is smooth, and the driving voltage can be reduced. In addition, since the tapered resin layer is formed using a resin for protecting the electrodes, the number of steps for forming the tapered resin layer is reduced.

According to the method of manufacturing an ink jet head of the present invention, the resin supplied into the ink flow path is deposited on the plate side by heating, and the communication surface between the ink discharge port and the ink flow path is formed. Ru can be easily formed on a curved surface of a resin.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an inkjet head according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a method of manufacturing the ink jet head of the embodiment.

FIG. 3 is an explanatory diagram showing a control unit of the ink jet head of the embodiment.

FIG. 4 is a cross-sectional view showing a configuration of the ink jet head of the embodiment.

FIG. 5 is an explanatory diagram showing an operation state of the ink jet head of the embodiment.

FIG. 6 is a perspective view schematically showing a configuration of a conventional inkjet head.

FIG. 7 is a cross-sectional view illustrating a configuration of the conventional inkjet head.

[Explanation of symbols]

 2 Piezoelectric ceramic plate 3 Cover plate 8 Groove 12 Ink flow path 31 Nozzle plate 32 Nozzle 73 Resin layer

Claims (3)

(57) [Claims] A nozzle plate 1. A ink discharge port is formed, the ink flow path communicating with Lee ink discharge port of the nozzle plate is formed, ejecting the ink in the ink flow path
An actuator section having an electrode for applying energy, wherein the electrode in the ink flow path is protected from ink.
Forming a tree layer over the electrode in the ink flow path
An ink jet head, wherein a tapered resin layer integrally formed with the resin layer is formed in a rectangular portion formed by the ink flow path and the nozzle plate. A nozzle plate wherein the ink discharge port is formed, in the manufacturing method of the ink-jet head having an actuator unit for an ink flow path is formed that communicates with the Lee ink discharge port of the nozzle plates, the ink flow A step of supplying a resin into a passage; a step of bonding a plate, which is not provided with the ink discharge ports serving as the nozzle plate, to the actuator unit; heating the actuator unit and the plate to form the ink flow path A step of depositing the resin inside the plate on the plate side, and a step of forming an ink discharge port in the plate. 3. A nozzle plate ink discharge port is formed, the ink flow path communicating with Lee ink ejection port of the nozzle plates are formed, ejecting the ink in the ink flow path
A method of manufacturing an ink jet head having an actuator section having an electrode for applying energy, wherein the electrode in the ink flow path is protected from ink.
Supplying a resin covering the electrode into the ink flow path , bonding the nozzle plate to the actuator section, heating the actuator section and the nozzle plate, A step of flowing a resin and depositing the resin on the nozzle plate side; and a step of removing the resin in the ink discharge port of the nozzle plate to communicate the ink discharge port with the ink flow path. Manufacturing method of an inkjet head.