JP2002326362A - Inkjet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet head wherein an electrostatic type actuator section and a frame are accurately and readily bonded to each other. SOLUTION: The inkjet head 1 comprises a nozzle plate 6 bonded to the electrostatic actuator 5 and an ink passage 14 that supplies ink to a common liquid chamber passage 11 of the electrostatic actuator 5 by communicating with the common liquid chamber passage 11 and is formed on the frame 4. A preliminary adhesive applying region Ar to which a preliminary adhesive for positioning the electrostatic actuator 5 to the frame 4 is to be applied when the electrostatic actuator 5 is bonded to the frame 4, is formed on the frame 4 in the inkjet head 1. As a result, it is possible to apply the preliminary adhesive before the electrostatic actuator 5 is bonded to the frame 4 with a primary adhesive, to enhance the assembling property of the inkjet head 1 and to miniaturize the ink jet head 1.

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 more particularly, to an ink-jet head for easily and accurately bonding an electrostatic actuator unit and a frame to each other.

[0002]

2. Description of the Related Art An ink jet recording apparatus does not require processes such as development and fixing and can perform recording in a non-contact manner. Therefore, the noise at the time of recording is extremely low, and high-speed printing is possible. It has many advantages such as a high degree of freedom of ink and the ability to use inexpensive plain paper.
Among the ink jet recording apparatuses, a so-called ink-on-demand type ink jet recording apparatus which discharges ink droplets only when recording is necessary does not require collection of unnecessary ink droplets for recording, and maintenance is performed. Because of its simplicity, small size, and low cost, it is currently receiving attention.

[0003] Also, recent ink jet recording apparatuses are required to have high speed and high print quality, and in order to achieve high speed and high print quality, it is necessary to use multiple nozzles and high density. In response to such a demand, an electrostatic inkjet head has appeared.

This electrostatic type ink jet head is
A pulse voltage is applied to an electrode provided opposite to the diaphragm in the pressurized liquid chamber, and the diaphragm is attracted by the negative or positive charge on the diaphragm surface corresponding to the positive or negative charge on the electrode surface. Bend. Then, the volume of the pressurized liquid chamber is reduced by the restoring action of the diaphragm when the voltage to the electrode is turned off, and the pressure in the pressurized liquid chamber is instantaneously increased to communicate with the pressurized liquid chamber. Ink droplets are ejected from the corresponding nozzle holes.

In such an electrostatic ink jet head, ink is supplied from a common liquid chamber to a pressurized liquid chamber through a resistance flow path, and a diaphragm provided in a part of the pressurized liquid chamber and a diaphragm provided to the diaphragm are provided. An actuator unit provided with opposed individual electrodes for displacing the diaphragm by electrostatic force generated by a driving voltage applied to the individual electrodes, thereby discharging ink from a nozzle hole communicating with the pressurized liquid chamber; And a frame provided with an ink flow path that supplies ink to the common liquid chamber in communication with the common liquid chamber of the unit, and is formed by bonding. For this bonding, an adhesive bonding method is used. Often.

[0006] Such an ink jet head is detachably mounted on a carriage in which the head moves in the main scanning direction, and performs a printing operation by discharging ink while being moved in the main scanning direction by the carriage.

In this ink jet head, the nozzle plate in which the nozzle holes are formed and the actuator section in which the pressurized liquid chamber is formed need to be positioned with high precision. Once determined, positioning can be performed by abutting the reference of the frame to which the actuator section is joined and the reference of the carriage. Therefore, as described above, the inkjet head and the carriage are configured to be detachable.

In the manufacture of an ink jet head, an actuator unit in which a nozzle plate is joined to an electrostatic actuator and a frame are joined. In this joining, a main adhesive is applied to a joining surface of the frame, and a CCD is attached. (Charge Coupled Device) The nozzle plate and the frame are imaged with a camera or the like, and the nozzle plate and the frame are aligned and joined.

[0009]

However, in an ink jet head, it is necessary to position the nozzle plate and the frame joined to the electrostatic actuator with high precision. When joining the joined actuator unit and frame, apply this adhesive to the joint surface of the frame, image the nozzle plate and frame reference with a CCD camera, etc., and align the nozzle plate and frame. Therefore, there is a problem that workability is poor, high-precision alignment is difficult, and miniaturization of the inkjet head is difficult.

Therefore, according to the first aspect of the present invention, an actuator section to which the nozzle plate is joined and an ink flow path which communicates with the common liquid chamber of the actuator section and supplies ink to the common liquid chamber are formed. When joining the frame and the frame, the actuator section and the frame are joined by the final joining adhesive by forming a temporary joining adhesive application area where the temporary joining adhesive for positioning with the actuator section is applied to the frame. It is an object of the present invention to provide an ink jet head which can apply a temporary bonding adhesive beforehand, can improve assembling performance, and can be downsized.

According to a second aspect of the present invention, a groove having a predetermined width and a predetermined depth is formed between the temporary bonding adhesive application area and the main bonding adhesive application area to which the main bonding adhesive is applied. As a result, even if the temporary bonding adhesive and the final bonding adhesive are applied at the same time, it is possible to prevent the two adhesives from being mixed and to cause poor curing, and to prevent the poor curing of the adhesive and the temporary bonding adhesive and the final bonding adhesive. It is an object of the present invention to provide an ink jet head which can improve the assembling performance by simultaneously applying a bonding adhesive, and has good performance.

According to a third aspect of the present invention, an instant adhesive is used as the temporary bonding adhesive, so that the time for removing the ink jet head from the bonding apparatus is reduced, the production efficiency is improved, and the assembling performance is further improved. It is intended to provide a simple inkjet head.

[0013]

According to the first aspect of the present invention, there is provided an ink jet head comprising: a plurality of pressurized liquid chambers filled with ink; A common liquid chamber for supplying the ink to the liquid chamber, a diaphragm provided in a part of each of the pressurized liquid chambers, and an individual electrode disposed to face each of the vibration plates with a predetermined gap therebetween An actuator unit that is connected to a nozzle plate having a plurality of nozzle holes that communicate with the pressurized liquid chambers and discharge the ink in the pressurized liquid chambers, and the common part of the actuator unit A frame formed with an ink flow path that communicates with the liquid chamber and supplies the ink to the common liquid chamber. The actuator section and the frame are joined, and the actuator is moved from the ink flow path of the frame to the common liquid chamber. Division of the common Supplying the ink to each of the pressurized liquid chambers through the chamber and the resistance flow path, deforming the vibration plate by an electrostatic force generated by a voltage applied between the vibration plate and the individual electrode, and performing the pressurization. In an ink jet head that generates pressure in a liquid chamber and discharges the ink in the pressurized liquid chamber from the nozzle hole, the frame includes:
The above object is achieved by providing a temporary bonding adhesive application region to which a temporary bonding adhesive for positioning with the actuator unit bonded to the nozzle plate is applied.

According to the above construction, the actuator section to which the nozzle plate is joined is joined to the frame having an ink flow path which communicates with the common liquid chamber of the actuator section and supplies ink to the common liquid chamber. Since the temporary bonding adhesive application area for applying the temporary bonding adhesive for positioning with the actuator portion is formed on the frame, the temporary bonding adhesive is applied before the actuator portion and the frame are bonded with the final bonding adhesive. The bonding adhesive can be applied, and the assembling performance can be improved, and the size can be reduced.

In this case, for example, as set forth in claim 2, the frame has a predetermined width between the temporary bonding adhesive application area and the main bonding adhesive application area where the main bonding adhesive is applied. A groove having a predetermined depth may be formed.

According to the above configuration, a groove having a predetermined width and a predetermined depth is formed in the frame between the temporary bonding adhesive application area and the main bonding adhesive application area where the main bonding adhesive is applied. Therefore, even if the temporary bonding adhesive and the final bonding adhesive are applied at the same time, it is possible to prevent the two adhesives from being mixed and causing poor curing, and to prevent the poor curing of the adhesive while temporarily bonding the adhesive. And the final bonding adhesive can be simultaneously applied to further improve the assembling performance and improve the performance.

Further, for example, the temporary bonding adhesive may be an instantaneous adhesive.

According to the above configuration, as the temporary bonding adhesive,
Since the instant adhesive is used, the time for removing the inkjet head from the joining device can be reduced, the production efficiency can be improved, and the assembling performance can be further improved.

[0019]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. It should be noted that the embodiments described below are preferred embodiments of the present invention, and therefore, various technically preferable limitations are added. However, the scope of the present invention is not limited to the following description. The embodiments are not limited to these embodiments unless otherwise specified.

FIGS. 1 to 8 show an embodiment of the ink jet head of the present invention. FIG. 1 shows an electrostatic ink jet head 1 to which an embodiment of the ink jet head of the present invention is applied. FIG. 2 is a sectional view of a main part of the inkjet head 1 of FIG.

In FIG. 1, the ink-jet head 1
A frame 4 having a filter 3 heat-welded to its lower surface on a joint 2 for supplying ink from an ink supply tank or an ink cartridge;
As shown in FIG. 2, an actuator unit 7 in which a nozzle plate 6 is adhesively bonded to an electrostatic actuator 5 is adhesively bonded on the frame 4.

Electrostatic actuator (actuator section)
5 is formed, for example, by etching silicon. The electrostatic actuator 5 has a plurality of individual electrodes 8 formed on the upper surface thereof. A pressurized liquid chamber 9 is formed at an opposing position on the individual electrode 8, and a diaphragm 10 is formed on the bottom surface of the pressurized liquid chamber 9. A common liquid chamber flow path (common liquid chamber) 11 is formed in the center of the electrostatic actuator 5. Between the electrostatic actuator 5 and the nozzle plate 6, a fluid resistance 12 communicating the common liquid chamber flow path 11 and each pressurized liquid chamber 9 is defined. As will be described later, the fluid resistance 12 The ink in the common liquid chamber flow path 11 is supplied to each pressurized liquid chamber 9.

The nozzle plate 6 is generally formed by a Ni electroforming method, and the nozzle plate 6 is formed with a nozzle hole 13 communicating with each pressurized liquid chamber 9. The nozzle plate 6 allows the ink in the pressurized liquid chamber 9 to pass through the nozzle holes 13.
From a recording medium such as paper.

The frame 4 has an ink flow path 14 communicating with the common liquid chamber flow path 11 and an insertion groove 15. The ink flow path 14 has an ink supply tank or an ink cartridge. To joint 2
Is supplied through the ink passage 14, and the ink flow path 14 supplies the supplied ink to the common liquid chamber flow path 11 of the electrostatic actuator 5.

The insertion groove 15 of the frame 4 has a driver I
FPC with C16 mounted by wire bonding
The cable 17 is inserted, and the FPC cable 17 is electrically connected to the individual electrodes 8 of the electrostatic actuator 5 by an anisotropic conductive film.

In order to seal a pressure chamber between the individual electrode 8 and the diaphragm 10, a diaphragm gap sealing is provided on an outer portion of the diaphragm 10 between the electrostatic actuator 5 and the nozzle plate 6. Agent 18 is applied and the nozzle plate 6
A nozzle plate sealant 19 is applied between the corners of the frame and the frame 4.

Next, an example of joining the electrostatic actuator 5 and the nozzle plate 6 will be described. In order to join the electrostatic actuator 5 and the nozzle plate 6, an adhesive is applied to the upper surface of the electrostatic actuator 5, that is, the upper surface of the silicon liquid chamber in which the pressurized liquid chamber 9 is formed. When the adhesive runs out during bonding of the adhesive, the ink ejection characteristics are affected.
It should be around μm. In this case, as a method of applying an adhesive to the upper surface of the electrostatic actuator 5 where the pressurized liquid chamber 9 is formed, for example, a transfer method can be used. In the transfer method, for example, the adhesive is thinned to a roller with a doctor blade, and the adhesive is transferred from the roller to a transfer pad.
Further, the adhesive is transferred from the transfer pad to the upper surface of the electrostatic actuator 5.

Next, the diaphragm gap sealant 18 is applied to the outer portion of the diaphragm 10 between the electrostatic actuator 5 and the nozzle plate 6 as described above. The diaphragm gap sealant 18 is applied to seal the gap (the entrance of the vibration chamber) of the diaphragm 10 to prevent moisture from entering the inside of the vibration chamber and displacing the diaphragm 10. It is.

A nozzle plate sealant 19 is applied between the corners of the nozzle plate 6 and the frame 4 to position the nozzle plate 6 and the electrostatic actuator 5. As the nozzle plate sealant 19, an ultraviolet-curing adhesive or an instant adhesive for temporary joining is used.

Then, the nozzle plate 6 formed by Ni electroforming and the electrostatic actuator 5 having the adhesive applied on its upper surface are aligned with each other, and a temporary pressurization is performed. In this case, if the adhesive to be used is an ultraviolet-curable adhesive, the adhesive is cured by irradiating ultraviolet (UV), and is subjected to main pressure to be heated and cured, so that the nozzle plate 6 and the electrostatic actuator 5 And the actuator unit 7
Assemble. If the electrostatic actuator 5 is long at the time of the heat bonding, the silicon forming the electrostatic actuator 5 and the nozzle plate 6 usually formed of Ni or SUS are warped due to a difference in linear expansion coefficient. appear. When this warpage occurs, the electrostatic actuator 5 may be broken due to internal stress.

Therefore, as the adhesive, it is preferable that the curing temperature is low, so that a two-component mixed type (room temperature curing type) epoxy adhesive is desirable. As the curing temperature of the adhesive, the lower the better, the better, but preferably from 40C to 100C.

At the time of joining the nozzle plate 6 and the electrostatic actuator 5, in order to easily and accurately align the nozzle plate 6 with the electrostatic actuator 5, as shown in FIG. And through holes 20 formed on the upper surface of both ends in the short side direction for alignment, and as shown in FIG. 4, formed in both ends of the upper surface of the electrostatic actuator (silicon liquid chamber substrate) 5 in the short side direction. As shown in FIG. 5, the alignment mark 21 is
By aligning, the nozzle plate 6 and the electrostatic actuator 5 are positioned with high accuracy. Note that the alignment mark 21 formed on the electrostatic actuator 5 is
Since the silicon liquid chamber substrate has 110 surfaces, it has a hexagonal shape as shown in FIG.

When the actuator unit 7 is assembled by joining the electrostatic actuator 5 and the nozzle plate 6 as described above, next, the joint 2 and the frame 4 to which the filter 3 is heat-welded are bonded and joined. An adhesive is applied to the upper surface of the frame 4 that has been joined to the joint portion 2 in order to adhesively join the actuator unit 7,
The actuator unit 7 is aligned with the actuator unit 7 and bonded to the upper surface of the frame 4 by adhesive bonding.

In the ink jet head 1 of the present embodiment, a temporary bonding adhesive region Ar is provided at both ends of the bonding surface (upper surface) of the frame 4 as shown by a dashed line in FIG. Actuator unit 7 and frame 4
In joining with the actuator unit 7 and the frame 4, first, the temporary joining adhesive area Ar
Is coated with an adhesive for temporary bonding. Next, a permanent bonding adhesive is applied to the upper surface of the frame 4, and the actuator unit 7 in which the nozzle plate 6 and the electrostatic actuator 5 shown in FIG. The actuator unit 7 is adhesively bonded to the upper surface.

In this case, as shown in FIG. 8, at both ends of the joint surface of the frame 4 with the actuator unit 7,
Between the temporary bonding adhesive region Ar and the final bonding adhesive region Br (region indicated by the two-dot line) to which the final bonding adhesive is applied,
A predetermined depth (for example, about 1 mm) and a predetermined width (for example,
A separation groove 30 of about 0.5 mm) may be formed.

In this manner, the temporary bonding adhesive region Ar
Can be prevented from being mixed with the temporary bonding adhesive applied to the final bonding adhesive and the final bonding adhesive applied to the final bonding adhesive region Br, and the two adhesives can be mixed and cured at the time of bonding. The occurrence of defects can be prevented.

When an instant adhesive that does not require pressurizing and heating is used as the temporary bonding adhesive, the inkjet head can be removed from the bonding apparatus in a few seconds, and the working efficiency can be improved.

As described above, the ink jet head 1
When the pulse voltage is applied to the individual electrode 8, the diaphragm 10 is deformed toward the individual electrode 8 by the electrostatic force and the volume of the pressurized liquid chamber 9 is increased. The ink flows from the flow path 11 through the fluid resistance 12. Here, when the pulse voltage applied to the individual electrode 8 is released, the electrostatic force acting on the diaphragm 10 disappears, and the diaphragm 10 returns to the original state.
The pressure in the pressurized liquid chamber 9 increases due to the elastic force of the vibration plate 10, and ink is ejected from the nozzle holes 13.

Although the invention made by the present inventors has been specifically described based on the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the gist of the invention. It goes without saying that it is possible.

[0040]

According to the first aspect of the present invention, there is provided an ink jet head which communicates with an actuator portion to which a nozzle plate is joined and a common liquid chamber of the actuator portion to supply ink to the common liquid chamber. When joining the frame with the road, the temporary joining adhesive application area for applying the temporary joining adhesive for positioning with the actuator section is formed on the frame. The temporary bonding adhesive can be applied before joining with the bonding adhesive, so that the assembling performance can be improved and the size can be reduced.

According to the second aspect of the invention, the frame has a predetermined width and a predetermined depth between the temporary bonding adhesive application area and the main bonding adhesive application area where the main bonding adhesive is applied. Since the grooves are formed, even if the temporary bonding adhesive and the main bonding adhesive are applied at the same time, it is possible to prevent mixing of the two adhesives and to prevent poor curing. By simultaneously applying the temporary bonding adhesive and the final bonding adhesive while preventing the assembly, the assembly performance can be further improved and the performance can be improved.

According to the ink jet head of the third aspect of the present invention, since the instant adhesive is used as the temporary bonding adhesive, the time for removing the ink jet head from the bonding apparatus can be shortened, and the production efficiency can be improved. Let me
The assembling performance can be further improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an inkjet head to which an embodiment of an inkjet head according to the present invention is applied.

FIG. 2 is a sectional view of a main part of the inkjet head of FIG. 1;

FIG. 3 is an enlarged plan view of the nozzle plate of FIG. 1;

FIG. 4 is an enlarged plan view of the electrostatic actuator of FIG. 1;

5 is an enlarged plan view of a through hole of the nozzle plate of FIG. 3 and an alignment mark of FIG. 4;

FIG. 6 is an enlarged plan view of the frame of FIG. 1 in which a temporary bonding adhesive region is formed on a bonding surface with an actuator unit.

FIG. 7 is a plan view of an actuator unit in which the electrostatic actuator and the nozzle plate of FIG. 1 are joined.

FIG. 8 is an enlarged plan view of the frame of FIG. 6 in which a separation groove is formed between a temporary bonding adhesive region and a main bonding adhesive region on a bonding surface with an actuator unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink jet head 2 Joint part 3 Filter 4 Frame 5 Electrostatic actuator 6 Nozzle plate 7 Actuator unit 8 Individual electrode 9 Pressurized liquid chamber 10 Vibrating plate 11 Common liquid chamber flow path 12 Fluid resistance 13 Nozzle hole 14 Ink flow path 15 Insertion groove Reference Signs List 16 driver IC 17 FPC cable 18 diaphragm gap sealant 19 nozzle plate sealant 20 through hole 21 alignment mark 22 positioning hole 30 separation groove Ar temporary bonding adhesive area Br final bonding adhesive area

Claims (3)

[Claims] 1. A plurality of pressurized liquid chambers filled with ink, a common liquid chamber communicated with each of the pressurized liquid chambers via a resistance flow path, and supplies the ink to each of the pressurized liquid chambers; A vibrating plate provided in a part of the pressurized liquid chamber, and an individual electrode disposed to face each of the vibrating plates with a predetermined gap therebetween, and communicate with each of the pressurized liquid chambers. An actuator unit connected to a nozzle plate having a plurality of nozzle holes for discharging the ink in the pressurized liquid chamber, and supplying the ink to the common liquid chamber by communicating with the common liquid chamber of the actuator unit A frame having an ink flow path formed therein, wherein the actuator section and the frame are joined to each other, and the ink passages from the ink flow path of the frame pass through the common liquid chamber and the resistance flow path of the actuator section. Supply the ink to the pressure chamber Deforming the vibrating plate with electrostatic force generated by a voltage applied between the vibrating plate and the individual electrodes to generate pressure in the pressurized liquid chamber, and causing the ink in the pressurized liquid chamber to be ejected by the nozzle In the inkjet head that discharges from the holes, the frame is provided with a temporary bonding adhesive application area to which a temporary bonding adhesive for positioning with the actuator unit bonded to the nozzle plate is applied. Inkjet head. 2. The frame according to claim 1, wherein a groove having a predetermined width and a predetermined depth is formed between the temporary bonding adhesive application area and the main bonding adhesive application area to which the final bonding adhesive is applied. The ink-jet head according to claim 1, wherein: 3. The ink jet head according to claim 1, wherein the temporary bonding adhesive is an instantaneous adhesive.