JP4324686B2 - Bonding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for adhering a piezoelectric element and a vibration film in the manufacture of an inkjet head using the piezoelectric element.
[0002]
[Prior art]
In recent years, inkjet printers have been used for printing on personal computers and the like. An ink jet nozzle is used in this ink jet printer. In general, an inkjet nozzle has a piezo element, a vibration film, an ink chamber, and an ink supply path for supplying ink for each nozzle. That is, an ink chamber and an ink supply path are formed from a nozzle plate having a vibration film and a nozzle. When the vibration film is pressed, ink is ejected from the ink chamber through the nozzle. It is the piezo element that transmits the vibration to the vibration film (that is, the ink chamber).
[0003]
Therefore, the inkjet head is required to dispose the piezoelectric element at an accurate position of the vibration film and to accurately transmit vibration to the vibration film.
[0004]
However, since the piezo element and the vibration film are often formed of different materials, the adhesion between the piezo element and the vibration film involves various problems. For example, strong adhesive strength cannot be obtained, or if the adhesive existing between the piezo element and the vibration film acts as an elastic body, the vibration of the piezo element is absorbed and cannot be accurately transmitted. If there is a variation, there is a problem that the ink ejection may vary and the printer may not be able to perform high-speed printing.
[0005]
In view of this, a contrivance has been made to minimize the influence on the ink ejection due to the variation in the thickness of the adhesive. For example, attempts have been made to add an adhesive to glass beads. However, this method also has technical problems such as the homogeneity of the particle size or number of the glass beads to be added and the adjustment of the wettability with the adhesive, and it is difficult to manage because there are too many elements to be managed. And since glass beads are expensive, it is disadvantageous in terms of cost.
[0006]
In addition, it is necessary to increase the number of nozzles in order to adapt to high-speed printing. However, since it is necessary to increase the number of piezo elements, it takes time to bond. The piezoelectric element itself is a fine structure of about 0.1 mm × 0.5 mm × 5 to 10 mm, and the tip portion is fragile. Therefore, the piezoelectric element may be damaged when the adhesive is applied. There is a problem that it takes.
[0007]
[Problems to be solved by the invention]
Therefore, there is a need for a method for simply and strongly bonding a piezo element and a vibration film and accurately transmitting vibration.
[0008]
[Means for Solving the Problems]
The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for easily and strongly bonding a piezo element and a vibration film, and to accurately transmit vibration. Is to provide.
[0009]
The present invention has, for each nozzle, a piezo element, a vibration film, an ink chamber, and an ink supply path for supplying ink. The vibration of the piezo element is transmitted to the vibration film, and ink is ejected from the nozzle. A method for bonding a piezoelectric element and a vibration film in an inkjet head to be printed,
Applying an adhesive to one end of the piezo element plate and drying;
A step of processing the piezo element plate dried from the adhesive into a comb shape so that a piezo element having a predetermined width is left according to the interval of the nozzles; and an adhesive for the piezo element processed into the comb shape Adhering one end to the vibrating membrane;
The present invention relates to a method for bonding a piezoelectric element and a vibration film.
[0010]
In a preferred embodiment, the adhesive and the vibration film are made of a thermosetting resin, and the bonding is performed by heating.
[0011]
The method of the present invention provides a method for easily and strongly bonding a piezo element and a vibration film. The obtained inkjet head can transmit the vibration of the piezoelectric element more accurately.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
【Example】
A method for bonding the piezoelectric element and the vibration film of the present invention will be described with reference to FIG. First, as shown in FIG. 1A, the piezo element plate 1 is fixed on the fixed plate 2. FIG.1 (b) is AA sectional drawing of Fig.1 (a), and the adhesion part is a cantilever state. When the adhesive 3 is applied to the tip of the piezo element plate 1 in this state, the state shown in FIG. 1C is obtained and dried. FIG. 1D is a sectional view taken along line AA in FIG. Next, as shown in FIG. 1E, the piezo element plate 1 is processed into a comb shape at appropriate intervals. As a result, a plurality of piezoelectric elements 4 having the adhesive 3 dried at the tip are formed. FIG. 1F is a cross-sectional view taken along the line AA in FIG.
[0013]
The obtained piezo element 4 is bonded to the vibration film. A schematic diagram of adhesion to the vibrating membrane is shown in FIG. The piezo element 4 obtained in FIG. 1 is inserted in the direction of the arrow P along a guide (not shown) in the space 5, and lightly P so that the diaphragm 6 and the adhesive 3 of the piezo element 4 come into contact with each other. Apply pressure in the direction and heat. The adhesive melts and adheres by heating. At this time, the piezo element 4 is pressed by the pressure applied in the P direction, and is bonded on the planned bonding surface of the vibration film 6.
[0014]
In this way, when the bonding is completed, the external electrode 7 is connected to this, and an ink jet head is formed. Alternatively, after connecting the external electrode 7 and the piezo element 4, the piezo element 4 may be adhered to the vibration film 6 to form an ink jet head.
[0015]
The method for bonding the piezo element plate 1 and the fixed plate 2 is not particularly limited. The adhesive may be determined in consideration of the material of the piezo element and the fixing plate. As the adhesive, a phenol novolac type epoxy resin is preferably used. The fixing plate 2 is installed for the purpose of damping the vibration so as not to transmit the vibration to the adjacent ink chamber after the piezoelectric element 4 transmits the vibration.
[0016]
The adhesive 3 applied to the piezo element plate 1 is not particularly limited as long as it is an adhesive that can be melted by heat and adhered to the vibration film 6. A thermoplastic resin or a thermosetting resin may be used, but a thermosetting resin is preferable in that it can be heat-bonded. Among them, it is preferable to make the vibration film to be bonded with a thermosetting resin and use the same thermosetting resin. As a result, the adhesion becomes strong and the adhesive does not act as an elastic body, so that the vibration of the piezo element is directly and accurately transmitted.
[0017]
As the thermosetting resin, an epoxy resin, a phenol resin, a polyimide resin, and a melamine resin are preferable.
[0018]
The adhesive 3 used in the present invention is used after being dissolved in a solvent. The solvent is not particularly limited as long as it is a resin that can dissolve a resin serving as an adhesive and can be easily dried. When using an epoxy resin, a phenol novolac type epoxy resin is preferable.
[0019]
The concentration of the adhesive is not particularly limited, but is preferably a concentration that can be disposed at the tip of the piezoelectric element. For example, in the case of an epoxy resin, 15 to 30% is preferable. 18-22% is more preferable.
[0020]
Further, the adhesive may contain a curing agent, a curing accelerator and the like that are usually used for thermosetting.
[0021]
After application, the adhesive is dried. Drying is performed at a temperature at which the thermosetting resin does not melt. Although it depends on the solvent, it is preferably 50 to 80 ° C. Thus, a piezoelectric element plate 1 having a dried adhesive 3 at one end as shown in FIGS. 1C and 1D is produced.
[0022]
Next, the piezo element plate 1 having the dried adhesive 3 at one end is processed into a comb shape. Processing is performed using a dicer, a band saw, a wire cutter, or the like. In the processing, it is necessary to make the interval between the generated piezo elements 4 constant. As shown in FIG. 2, the inkjet head 10 includes an ink supply chamber 11, an ink supply port 12, and an ink chamber 13 that are configured by an ink chamber member 15 having a nozzle 14 and a vibration film 6. The piezo element 4 is bonded to the vibration film 6 via the adhesive 3, but the position thereof is substantially the center position of the ink chamber 13, so that the ink is accurately adjusted according to the vibration of the piezo element 4. In addition, ink can be ejected from the nozzle 14. Such a position is determined along a guide (not shown) in the space 5 as described above. Therefore, the piezoelectric element plate 1 is processed into a comb shape by deleting the distance (B in FIG. 2) between the spaces 5 shown in FIG.
[0023]
Thereby, the comb-like piezo element 4 shown in FIGS. 1E and 1F is obtained.
[0024]
Next, a piezo element is inserted along a guide (not shown) in the space 5 shown in FIG. 2 and heated while lightly applying pressure in the P direction. The case where an epoxy resin is used is demonstrated based on FIG. When heated in a solidified state (FIG. 3a), the solid state epoxy resin melts as the temperature rises and changes to a liquid state (FIG. 3b), and rapidly hardens and solidifies at a certain temperature. (C of FIG. 3), it adheres to the vibrating membrane 6. At this time, since the piezo element 4 is pressed at a constant pressure, the vibration film 6 and the plurality of piezo elements are uniformly bonded.
[0025]
If the same resin as that of the vibration film is used as the adhesive for the piezo element, the adhesive strength becomes stronger than when the resin is bonded with a different resin.
[0026]
[Action]
The method of the present invention is characterized in that an adhesive is applied before a piezo element is processed into a comb shape. In the case of an inkjet head in which piezo elements are arranged corresponding to a plurality of nozzles, it is desirable that the amount of adhesive applied to each piezo element is uniform, but when applying an adhesive after processing into a comb shape, bonding Viscosity, amount (thickness) of the agent must be finely managed, which is very laborious, whereas according to the method of the present invention, by applying the adhesive before comb processing of the piezo element, As long as the coating thickness is managed, the amount of adhesive becomes uniform even after comb processing, so that process management becomes extremely easy. In this case, by dissolving the adhesive in a solvent, workability at the time of application is improved, and management of the thickness of the adhesive becomes easy. In addition, since it can be applied thinner, it is possible to suppress the adhesive from acting as an elastic body, and to efficiently transmit the displacement of the piezoelectric element to the vibration film.
[0027]
(Example)
First, a piezo element plate having a thickness of 0.5 mm was attached to a fixed plate as shown in FIG. Next, 20% by weight of a phenol novolac type epoxy resin (trade name Epicron N770: manufactured by Dainippon Ink Co., Ltd.) and a phenolic curing agent (trade name Phenolite TD2106: manufactured by Dainippon Ink Co., Ltd.) and imidazole are used as adhesives. A varnish in a state where the curing accelerator of the system compound was dissolved in acetone so as to be an appropriate amount was prepared. This varnish was applied to the surface corresponding to the vibration film adhesion of the piezo element plate. After coating, the coated surface was dried at 50 ° C. for 15 minutes, the solvent was removed, and a piezo element plate with an adhesive applied to one end as shown in FIG. 2C was formed.
[0028]
Next, the end face to which the adhesive for the piezoelectric element was applied was processed using a wire cutter, and a piezo having a width of 0.15 mm, a thickness of 0.5 mm, and a length of 7 mm while making a notch with a width of 0.25 mm. The element was formed, and the processed surface was washed with water containing a surfactant to produce a comb-shaped piezo element as shown in FIG.
[0029]
Next, the obtained comb-shaped piezo element was inserted along the guide of the space 5 in FIG. 2, heated to 120 ° C. to melt the adhesive, and pressed against the vibration film of the inkjet head with a pressure of 10 KPa. The vibration film of the inkjet head was formed of the same phenol novolac type epoxy resin (Epicron N770) as the adhesive. While pressing the piezo element against the vibration film at a pressure of 10 KPa, the temperature was raised to 200 ° C., heated and held for 5 minutes, the adhesive was cured, and the piezo element and the vibration film were bonded.
[0030]
When printing was carried out using the ink jet head thus obtained, it was possible to print beautifully, and it was shown that the bonding method of the present invention is useful.
[0031]
【The invention's effect】
According to the present invention, a method for easily and strongly bonding a piezoelectric element and a vibration film is provided. The obtained inkjet head can transmit the vibration of the piezoelectric element more accurately.
[Brief description of the drawings]
FIG. 1 is a view showing a bonding method of the present invention.
FIG. 2 is a schematic diagram of an inkjet head having a piezoelectric element.
FIG. 3 is a diagram showing a phase change of an epoxy resin adhesive.

Claims (2)

Each nozzle has a piezo element, a vibration film, an ink chamber, and an ink supply path for supplying ink, and transmits the vibration of the piezo element to the vibration film to print the ink by ejecting from the nozzle. A bonding method between a piezoelectric element and a vibration film in a head,
Applying an adhesive to one end of the piezo element plate and drying;
Processing the piezo element plate dried with the adhesive into a comb shape so that a piezo element with a predetermined width remains in accordance with the interval of the nozzles; and an adhesive for the piezo element processed into the comb shape Adhering one end to the vibrating membrane;
Only including,
A method for bonding a piezoelectric element and a vibration film, wherein the adhesive and the vibration film are made of a thermosetting resin, and the bonding is performed by heating . The adhesive and the vibrating membrane ing from the same resin, the method described in 請 Motomeko 1.

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