JPH0948133A - Manufacture of ink jet printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent piezoelectric members from being separated in their bonded part even though the piezoelectric member repeats expansion and contraction by variation in temperature when two sheets of piezoelectric members are bonded to each other in a substrate of an ink jet printer head. SOLUTION: An adhesive 16 having an almost same linear expansion coefficient as that piezoelectric members 6, 7 is manufactured. The piezoelectric members 6, 7 are bonded to each other by using the adhesive 16.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for manufacturing an on-demand type ink jet printer head.

[0002]

2. Description of the Related Art Conventionally, a nozzle plate having an ink discharge port is fixed to the tips of a large number of pressure chambers connected in parallel to an ink supply unit, and the ink pressure in the pressure chambers is selectively increased according to a print command. An on-demand inkjet printer head is known in which an ink droplet is ejected from an ink ejection port.

As a method of increasing the ink pressure in the pressure chamber of such an ink jet printer head to eject ink droplets, at least a part of the side walls arranged on both sides of the pressure chamber is formed by a piezoelectric member, and the side surface of the side wall is formed. Japanese Patent Laid-Open No. 63-247051 discloses a method in which an electrode is provided on the substrate and a voltage is applied to the electrode to deform the side wall in the shear mode.

Here, when a pair of piezoelectric members are bonded to each other in the process of manufacturing an ink jet printer head, or a plate-shaped member such as a ceramics substrate or a glass substrate is bonded to a piezoelectric member to form a substrate, Bubbles may enter between the adhesive surfaces. When such bubbles enter, the adjacent pressure chambers leak due to the bubbles, and the ink pressure in each pressure chamber cannot be increased accurately according to the print command. Therefore, when the piezoelectric members are bonded together or the piezoelectric member and the plate-shaped member are bonded together, it is necessary to prevent bubbles from entering between the bonded surfaces.

As a method of bonding so that air bubbles do not enter between the bonding surfaces, in JP-A-61-292244 and JP-A-4-14636, a plate-shaped member having an adhesive applied to the bonding surface is vacuumed. A method is disclosed for removing bubbles from the adhesive by placing it in an atmosphere.

[0006]

However, in the bonding method disclosed in the above-mentioned JP-A-61-292244 and JP-A-4-14636, the linear expansion coefficient of the plate member and the linear expansion coefficient of the adhesive are Is not considered at all. Therefore, when the difference in linear expansion coefficient between the plate-shaped member and the adhesive is large, the plate-shaped member and the adhesive may be separated while repeatedly expanding and contracting due to temperature change.

When the piezoelectric member or the plate-shaped member and the adhesive are separated from each other in the ink jet printer head, the pressure chambers adjacent to each other leak, and the ink pressure in each pressure chamber can be increased accurately according to the print command. Disappear.

Therefore, according to the first aspect of the present invention, even if the piezoelectric member and the adhesive repeatedly expand and contract due to temperature change, the piezoelectric member and the adhesive can be prevented from peeling, and the pressure chambers adjacent to each other leak due to the peeling. Provided is a method for manufacturing an inkjet printer head that does not have any problems.

Further, according to a second aspect of the invention, even if the piezoelectric member, the plate-shaped member and the adhesive repeatedly expand and contract due to temperature change, the piezoelectric member and the adhesive are separated from each other and the plate-shaped member and the adhesive are separated. (EN) A method for manufacturing an inkjet printer head, which can prevent separation between the pressure chambers and the pressure chambers adjacent to each other due to the separation.

[0010]

According to a first aspect of the present invention, as an adhesive for laminating and adhering two piezoelectric members on a substrate of an ink jet printer head, the linear expansion coefficient of these piezoelectric members is substantially equal. An adhesive having a linear expansion coefficient and mixed with a filler is used. Then, apply this adhesive to the bonding surface of the piezoelectric member by screen printing,
The piezoelectric member on which the adhesive is screen-printed is left in a vacuum atmosphere for a predetermined time to remove bubbles contained in the adhesive, and the piezoelectric members are bonded in a vacuum atmosphere and then returned to the atmosphere and heated. By pressurizing, the bubbles remaining in the adhesive are further defoamed. Therefore, almost no bubbles are contained in the adhesive that bonds the piezoelectric members to each other, and even if the piezoelectric member and the adhesive repeatedly expand and contract due to temperature change, the piezoelectric member and the adhesive can be prevented from peeling off. It is possible to prevent leakage between the matching pressure chambers.

According to a second aspect of the present invention, the linear expansion coefficient of the piezoelectric member and the line of the plate-shaped member are used as an adhesive for laminating and bonding the piezoelectric member and the plate-shaped member other than the piezoelectric member on the substrate of the ink jet printer head. An adhesive having a linear expansion coefficient close to both the expansion coefficient and a filler mixed therein is used. Then, this adhesive is applied by screen printing to one of the bonding surface of the piezoelectric member and the bonding surface of the plate-shaped member, and the piezoelectric member or plate-shaped member on which the adhesive is screen-printed is left for a predetermined time in a vacuum atmosphere. By removing the bubbles contained in the adhesive by doing so, the piezoelectric member and the plate-like member are bonded in a vacuum atmosphere, and then returned to the atmosphere and heated and pressed to remain in the adhesive. The bubbles are further defoamed. Therefore, almost no bubbles are contained in the adhesive that bonds the piezoelectric member and the plate-shaped member, and even if the piezoelectric member, the plate-shaped member, and the adhesive repeatedly expand and contract due to temperature changes, the piezoelectric member and the plate-shaped member The peeling of the adhesive from the member can be prevented, and the leak between adjacent pressure chambers can be prevented.

[0012]

FIG. 1 shows a first embodiment of the present invention.
A description will be given based on FIG. As shown in FIG. 1, the inkjet printer head 1 has a top plate 3 with respect to a substrate 2.
And the nozzle plate 4 are bonded together.

The substrate 2 is formed in a three-layer structure by bonding two layers of piezoelectric members 6 and 7 on the bottom plate 5. The bottom plate 5 is made of ceramics or glass having high rigidity and less thermal deformation, and has a plate thickness of 0.5 to 5
mm. The piezoelectric members 6 and 7 are bonded in such a manner that they are polarized in the plate thickness direction so that the polarization directions are opposite.

Further, by grooving the substrate 2, a large number of parallel grooves 8 extending from the upper surface of the piezoelectric member 7 to the inside of the piezoelectric member 6 and parallel to each other and a large number of side walls 9 separating these grooves 8 are formed. And are formed alternately. The groove processing is performed by using a diamond wheel of a dicing saw used for cutting the IC wafer or the like. Further, these grooves 8 are formed so as to open on the front side of the substrate 2 and close the back side. Further, although the dimensions of the groove 8 are determined by the specifications of the inkjet printer head, for example, the depth dimension is 0.2 to 1 mm, the width dimension is 20 to 200 μm,
The length dimension is formed to 5 to 500 mm.

Next, the substrate 2 having the groove 8 and the side wall 9 is subjected to electroless plating to form an electrode 10 on the side surface of the side wall 9 and on the upper surface of the piezoelectric member 7. Wiring pattern 1 continuous with these electrodes 10
Form one. Further, when the inkjet printer head 1 is completed using the substrate 2, the electrode 10 is covered with an insulating film 12 in order to prevent the electrode 10 from coming into contact with ink.

The top plate 3 is bonded to the substrate 2 on which the groove 8 and the side wall 9 and the electrode 10 and the insulating film 12 are formed in this manner so as to cover the opening surface on the top side of the groove 8, and Groove 8
The nozzle plate 4 is adhered so as to cover the front end side opening surface of the
A number of pressure chambers 13 are formed by surrounding each groove 8 with the top plate 3 and the nozzle plate 4. The nozzle plate 4
A plurality of ink discharge ports 14 communicating with each pressure chamber 13.
An ink supply passage 1 is formed on the lower surface of the top plate 3 and is connected to each pressure chamber 13 and an ink supply pipe (not shown) for supplying ink to these pressure chambers 13 is connected.
5 is formed.

Now, the step of adhering the piezoelectric members 6 and 7 to each other will be described with reference to FIG. First, the adhesive 16 having a linear expansion coefficient substantially equal to the linear expansion coefficient of the piezoelectric members 6 and 7 is prepared. The adhesive 16 can be produced by mixing an adhesive having resistance to ink, for example, an epoxy adhesive with a filler made of fine ceramic powder or the like. Then, as shown in FIG. 3A, the adhesive 16 is screen-printed on the adhesive surface of one piezoelectric member 6 using a screen printing plate 17. According to this screen printing, the adhesive 16 can be applied very thinly, for example, to a thickness of 5 to 10 μm.

Next, the piezoelectric member 6 screen-printed with the adhesive 16 is attached to the rotary pump 1 as shown in FIG. 3 (b).
8 into a vacuum device 19 equipped with a rotary pump 18
Is left for a predetermined time, for example, 10 minutes to 1 hour in a vacuum atmosphere created by driving. The degree of vacuum required in this case is about 1 Torr.
It is a value easily obtained by driving 8. Then, after the piezoelectric member 6 on which the adhesive 16 is screen-printed is left in a vacuum atmosphere for a predetermined time, the piezoelectric member 6 and the piezoelectric member 7 are bonded via the adhesive 16 in the vacuum device 19. In this case, a weight 20 is attached to apply light pressure.

After the piezoelectric members 6 and 7 are adhered to each other in the vacuum device 19, the piezoelectric members 6 and 7 are taken out from the vacuum device 19 and attached to an adhesive jig 21 as shown in FIG. And pressurize by heating. In this case, the applied pressure is 1 to 3 kg / cm ² , and the heating temperature is selected within the range of 40 to 200 ° C., which is suitable for the type of the adhesive 16.

In the ink jet printer head 1 having such a structure, when a voltage is applied to the electrode 10 via the wiring pattern 11 in a state where ink is supplied into the pressure chamber 13, the side wall formed by the piezoelectric members 6 and 7. 9 deforms in shear mode in the direction of increasing the volume of the pressure chamber 13,
Eventually, the side wall 9 suddenly returns to the initial position. And
When the side wall 9 suddenly returns to the initial position, the ink in the pressure chamber 13 is pressurized to eject a part of the ink as an ink droplet from the ink ejection port 14. In addition, in order to prevent crosstalk during the ejection of these ink droplets,
The even-numbered pressure chambers 13 and the odd-numbered pressure chambers 13 are alternately pressurized. Further, since the ink ejection port 14 is formed in a taper shape whose diameter is gradually reduced toward the tip side,
Ink droplets are smoothly ejected from the ink ejection port 14.

Adhesive 1 in which two piezoelectric members 6 and 7 are adhered
Since the coefficient of linear expansion of No. 6 is substantially equal to the coefficient of linear expansion of the piezoelectric members 6 and 7, the piezoelectric members 6 and 7 are affected by the temperature change.
When is expanded or contracted, the adhesive 16 is also expanded or contracted in the same manner.
Therefore, even if the piezoelectric members 6 and 7 and the adhesive 16 repeatedly expand and contract due to temperature change, the bonded state between the piezoelectric members 6 and 7 and the adhesive 16 is reliably maintained. Therefore, the piezoelectric members 6,
7 and the adhesive 16 are not separated from each other, the problem that the adjacent pressure chambers 13 leak due to the separation can be solved, and the ink pressure in the pressure chambers 13 can be accurately increased according to the print command. At the same time, it is possible to reliably eject ink droplets according to the print command.

Although the viscosity of the adhesive 16 is increased by mixing the filler, the adhesive 16 is applied to the adhesive surface of the piezoelectric member 6 by screen printing so that the adhesive 16 can be applied in a thin and uniform film thickness. You can Then, since the thickness of the adhesive 16 is reduced, the rate of change in volume of the pressure chamber 13 when the side wall 9 is deformed in the shear mode is increased, and the ejection performance of ink droplets from the ink ejection port 14 is improved. FIG. 2 illustrates the rate of change in the volume of the pressure chamber 13 when the shear mode is changed when the thickness of the adhesive 16 between the piezoelectric members 6 and 7 is changed. FIG. As a result, the adhesive 16 is applied thinly, and FIG. 2B shows the adhesive 16 applied thick. Since the adhesive 16 does not deform in the shear mode, the volume change rate of the pressure chamber 13 becomes smaller as the film thickness of the adhesive 16 becomes thicker, and the ink droplet ejection performance deteriorates. That is, as described above, by reducing the film thickness of the adhesive 16, the ink droplet ejection performance is improved.

Next, by leaving the piezoelectric member 6 screen-printed with the adhesive 16 in a vacuum atmosphere for a predetermined time, the bubbles 23 contained in the screen-printed adhesive 16 are removed. By thinly applying the adhesive 16 by screen printing, defoaming of the bubbles 23 from the adhesive 16 in a vacuum atmosphere is promoted. Then, in the same vacuum atmosphere, the piezoelectric members 6 and 7 are bonded together by the adhesive 1.
Bonding via 6 can prevent bubbles from entering the adhesive 16 during this bonding.
Furthermore, the viscosity of the adhesive 16 is lowered by putting the piezoelectric members 6 and 7 bonded in a vacuum atmosphere in a high temperature tank 22 and applying heat and pressure, and the bubbles 23 trapped in the adhesive 16 are removed from the adhesive 16. The bubbles 23 can be discharged from the inside, and the bubbles 23 remaining in the adhesive 16 can be further reduced.

Since the air bubbles 23 contained in the adhesive 16 are reduced in this way, when the grooves 8 and the side walls 9 are formed by adhering the piezoelectric members 6 and 7 to each other, the adjacent grooves 8 are separated from each other. Bubbles with large dimensions, such as 20
Bubbles larger than the width of the side wall 9 and exceeding .mu.m are adhesive 16
It does not remain inside. Therefore, after the ink jet printer head 1 is formed, the pressure chambers 13 adjacent to each other do not leak due to the air bubbles remaining in the adhesive 16, and the ink droplets are surely ejected in accordance with the print command. Can be made.

In the present embodiment, the case where the two piezoelectric members 6 and 7 are bonded with the adhesive 16 having a linear expansion coefficient substantially equal to the linear expansion coefficient of the piezoelectric members 6 and 7 is an example. However, the piezoelectric member and a plate-shaped member other than the piezoelectric member, for example, a ceramics substrate or a glass substrate may be bonded to form the substrate. In this case, an adhesive having a linear expansion coefficient close to both the linear expansion coefficient of the piezoelectric member and the linear expansion coefficient of the plate-shaped member is prepared, and the piezoelectric member and the plate-shaped member are formed using this adhesive. To glue. The linear expansion coefficient of the produced adhesive can be adjusted by changing the amount and type of filler to be mixed.

Next, a second embodiment of the present invention will be described with reference to FIG.
It will be described based on. The same parts as those described with reference to FIGS. 1 to 3 are designated by the same reference numerals, and description thereof will be omitted (same below). The method of manufacturing the inkjet printer head of the present embodiment is basically the same as the method of manufacturing shown in FIGS. The difference is that the adhesive 16
When the screen-printed piezoelectric member 6 is adhered to the piezoelectric member 7 after being left in a vacuum atmosphere for a predetermined time, the piezoelectric members 6 and 7 are opposed to each other with one end side contacting and the other end side being separated from each other. That is, the piezoelectric member 7 is rotated with the contact portion between the piezoelectric members 6 and 7 as a fulcrum, and the bonding between the piezoelectric members 6 and 7 is gradually performed from one end side to the other end side.

By adhering the piezoelectric members 6 and 7 in this manner, the air located between the piezoelectric members 6 and 7 is adhered to the piezoelectric members 6 and 7, and the air between the piezoelectric members 6 and 7 is adhered to each other. The bubbles are gradually extruded from the sheet, and the bubbles that enter the adhesive 16 when the piezoelectric members 6 and 7 are bonded to each other are further reduced.

Next, a third embodiment of the present invention will be described with reference to FIG.
It will be described based on. The method of manufacturing the inkjet printer head of the present embodiment is basically the same as the method of manufacturing shown in FIGS. The different point is that when the bonded piezoelectric members 6 and 7 are put into the high temperature tank 22, they are mounted on the bonding jig 21, but at this time, they are mounted by mounting an elastic member 24 such as silicon having a thickness dimension of several mm. Is.

In this way, by attaching the piezoelectric members 6 and 7 to the adhesive jig 21 via the elastic members 24, the adhesive 16 between the piezoelectric members 6 and 7 is uniformly applied with pressure. Therefore, the film thickness of the adhesive 16 becomes more uniform, and the bubbles remaining in the adhesive 16 become smaller.

[0030]

According to the first aspect of the present invention, even if the piezoelectric member and the adhesive repeatedly expand and contract due to a temperature change, the piezoelectric member and the adhesive can be prevented from peeling off, and by this peeling, the adjacent pressure chambers can be prevented. It is possible to prevent mutual leakage.

According to the second aspect of the invention, even if the piezoelectric member, the plate-shaped member and the adhesive repeatedly expand and contract due to temperature change, the piezoelectric member and the adhesive are separated from each other, and the plate-shaped member and the adhesive are separated. It is possible to prevent the separation between the pressure chambers and the adjacent pressure chambers from leaking.

[Brief description of drawings]

FIG. 1 is a perspective view showing an inkjet printer head according to a first embodiment of the present invention with a part thereof cut away.

FIG. 2 is a front view for explaining the volume change rate of the pressure chamber at the time of shear mode deformation due to the difference in film thickness of the adhesive agent that adheres the piezoelectric members to each other. FIG. It is a state where it is applied, and (b) is a state where the adhesive is applied thickly.

3A and 3B are diagrams for explaining a step of adhering a pair of piezoelectric members. FIG. 3A is a perspective view illustrating a step of screen-printing an adhesive using a screen printing plate, and FIG. A front view illustrating a step of putting a screen-printed piezoelectric member in a vacuum atmosphere to remove bubbles from an adhesive and to bond the piezoelectric members to each other in the vacuum atmosphere.
(C) is a front view explaining the process of heating and pressurizing the adhered piezoelectric members.

FIG. 4 is a front view showing a step of bonding piezoelectric members to each other in a vacuum atmosphere in the second embodiment of the invention.

FIG. 5 is a front view illustrating a step of heating and pressing the bonded piezoelectric members in the third embodiment of the present invention.

[Explanation of symbols]

 1 Inkjet printer head 2 Substrate 3 Top plate 4 Nozzle plate 6,7 Piezoelectric member 8 Groove 9 Side wall 10 Electrode 13 Pressure chamber 14 Ink ejection port 16 Adhesive

Claims (2)

[Claims] 1. A substrate to which two piezoelectric members are laminated and adhered, a large number of grooves and side walls alternately formed on the piezoelectric member, electrodes provided on the side walls, and an opening surface on the top side of the grooves. The top plate fixed to the substrate so as to cover it, the nozzle plate fixed to the substrate so as to cover the front end side opening surface of these grooves by forming a large number of ink ejection openings corresponding to the grooves, and the groove. In an inkjet printer head having a pressure chamber formed by being surrounded by the top plate and the nozzle plate, one of adhesives mixed with filler having a linear expansion coefficient substantially equal to that of the piezoelectric member is used. Screen printing is performed on the bonding surface of the piezoelectric member, the piezoelectric member is left in a vacuum atmosphere for a predetermined time, the piezoelectric members are bonded in a vacuum atmosphere, and the bonded piezoelectric member is returned to the atmosphere and heated and pressed. Special Inkjet printer head manufacturing method. 2. A substrate in which a piezoelectric member and a plate-shaped member other than the piezoelectric member are laminated and adhered, a plurality of grooves and side walls which are alternately formed on the substrate and at least a part of which is the piezoelectric member, An electrode provided on the side wall, a top plate fixed to the substrate so as to cover the opening surface on the top side of the groove, and a large number of ink ejection openings corresponding to the groove are formed to open the opening surface on the tip side of these grooves. In an inkjet printer head having a nozzle plate fixed to the substrate so as to cover it, and a pressure chamber formed by surrounding the groove with the top plate and the nozzle plate, a linear expansion coefficient of the piezoelectric member and the plate shape Screen-printing on one of the adhesive surface of the piezoelectric member and the adhesive surface of the plate-shaped member, an adhesive containing a filler having a linear expansion coefficient close to both the linear expansion coefficient of the member, Piezoelectric member or The plate-shaped member is left in a vacuum atmosphere for a predetermined time, the piezoelectric member and the plate-shaped member are bonded in a vacuum atmosphere, and the bonded piezoelectric member and the plate-shaped member are returned to the atmosphere and heated. A method for manufacturing an inkjet printer head, which comprises applying pressure.