JP3414495B2 - Laminated ink jet recording head and method of manufacturing driving body suitable for the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a piezoelectric vibrator attached to a partial region of a pressure generating chamber communicating with a nozzle opening, and the flexural vibration of the piezoelectric vibrator compresses the pressure generating chamber to generate ink droplets. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording head to be generated, more specifically, a structure of a piezoelectric vibrator, and a manufacturing method thereof.

[0002]

2. Description of the Related Art An ink jet recording head in which a piezoelectric vibrating plate is stretched over a vibrating plate forming a part of a pressure generating chamber, and the volume of the pressure generating chamber is changed by flexural vibration of the piezoelectric vibrating plate to generate ink droplets. Is capable of displacing a wide area of the pressure generating chamber, so that it is possible to stably generate ink droplets. When utilizing the flexural vibration of the piezoelectric vibrator as described above, the surface of the piezoelectric vibrator needs to be sufficiently bonded to the vibration plate constituting the pressure generating chamber, and therefore, JP-A-5-267742 discloses. As shown, in the drive electrode area of the substrate to which the piezoelectric vibration plate is attached, the drive electrode is made of a material that has conductivity and has sufficient bonding force when firing the piezoelectric material, and does not directly contribute to piezoelectric vibration. An actuator has been proposed in which a joining electrode between the piezoelectric vibrator and the substrate is enhanced by forming a lead electrode of the other electrode in the region by using the same material.

On the other hand, the ink jet recording head is a printing apparatus suitable for graphic printing because it is possible to perform printing with extremely excellent color developability by selecting an ink. Therefore, in recent years, it has been particularly required to improve the recording density. Therefore, the nozzle arrangement pitch has become extremely small. In such an ink jet recording head, since the size of the piezoelectric vibrator is inevitably small, it is not only difficult to bring the tip of the piezoelectric vibrator into contact with the common electrode, but even if they are bonded, However, since the degree of variation varies among the piezoelectric vibrators, the tip A of the piezoelectric vibrator is easily lifted from the extraction electrode B as shown in FIG. 8, the bonding force with the substrate is weakened, and the piezoelectric element is formed on the upper surface. One of the problems is that the electrode thickness of the connection point D between the common electrode C and the extraction electrode B is reduced, and the reliability of the inkjet printer is unreliable.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of these problems, and an object thereof is to positively utilize the array structure of piezoelectric vibrators of an ink jet recording head. An object of the present invention is to provide an ink jet recording head capable of firmly bonding a piezoelectric vibrator to a vibration plate serving as a substrate. Another object of the present invention is to
An object of the present invention is to propose a method for manufacturing a driving body suitable for driving an inkjet recording head.

[0005]

In order to solve such a problem, according to the present invention, a plurality of nozzle opening rows in which a plurality of nozzle openings are arranged in a row are communicated with each of the nozzle openings and are common. Flow path forming member configured by arranging pressure generating chambers sealed in the vibration plate in parallel with each other at a constant interval, and a first member formed in the vibration plate corresponding to the pressure generating chambers. Of the electrode, a second electrode formed on the surface of the diaphragm at the center of the region on the opposite side of each nozzle opening row, and one of the first electrodes facing each other with the second electrode interposed therebetween. from near the other end, and the piezoelectric vibrator is formed so as to be continuous in the vicinity of the other end of the other of the first electrode, the table of the piezoelectric vibrator
A third electrode formed on the surface, the first electrode and
Piezoelectric vibration whose displacement region is the region sandwiched by the third electrode
And a piezoelectric driving means including a child .

[0006]

[Action] Since pressure <br/> electrostatic vibrator consecutive to the two pressure generating chambers facing are disposed, the number <br/> end face of the piezoelectric vibrator is reduced, it occurs at the end face There is less licking.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is an exploded perspective view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view in which reference numerals 1, 1, and 1 denote first members integrally formed by firing, respectively. As shown in FIG. 3, it comprises a spacer member 2 and a diaphragm 5. The spacer member 2 is a ceramic plate such as zirconia (ZrO2) having a thickness suitable for forming the pressure generating chambers 50, 51 having a depth of about 150 μm. Through holes to be pressure generating chambers 50, 51 in the substrate made of
, And 4, 4, 4, ... Are arranged and drilled in rows and in a staggered manner.

The vibrating plate 5 exhibits a sufficient bonding force when integrally fired with the spacer member 2 and is elastically deformed by the strain of the piezoelectric vibrators 6, 6, 6, ... In the embodiment, the spacer member is made of the same zirconia thin plate having a thickness of 10 μm. 6,
.. are piezoelectric vibrators formed by sintering on the surface of the vibrating plate, one half 6a of which is formed in the through holes 3, 3, 3, .. The half 6b faces through holes 4, 4, 4, ... Forming the pressure generating chambers of the other row, and the through holes 3, 4 of the pressure generating chambers are formed in the central portion 6c.
And the pressure generating chambers 50 and 51 are connected to each other and are joined to the common electrode extraction electrode 32a described later.

Returning to FIG. 1 and FIG. 2 again, reference numeral 7 in the drawing is
A lid plate integrally attached to the other surface of the spacer member 2. In this embodiment, the lid plate is made of a zirconia thin plate having a thickness of 150 μm, and has nozzle openings 21, 21, 21, ...
2 ... and pressure generating chambers 50, 50, 50 ..., 51, 5
, And 9, 9, 9 ..., and through holes 10, 11 for forming reservoirs 53, 54, which will be described later, and pressure generating chambers 50, 50. , 50, ...
... 51, 51, 51 ... through holes 12, 12,
.., 13, 13, 13, ..

Reference numeral 15 is an ink supply flow path forming plate, which is suitable for forming an ink flow path and has a substantially V-shape for forming the reservoirs 53 and 54 on a plate material having corrosion resistance such as 150 μm stainless steel. Arranged through holes 10, 11, pressure generating chambers 50, 51 and nozzle openings 21, 21, 21 ...
It is configured by forming through holes 16 and 17 that connect 22, 22, 22 ... Through-hole 1 serving as reservoirs 53, 54
0 and 11 are ink supply ports 18 and 1 provided in the cover plate 7.
, 18 and so on, and from there through through holes 12 and 13, pressure generating chambers 50, 50, 50, ...
Ink consumed by printing can be supplied to 1, 51, ....

A nozzle plate 20 has a diameter of 40 μm.
Nozzle openings 21, 21, 21, ..., 22, 22, 22
It is made of a stainless steel plate having a thickness of 60 μm and is suitable for perforating each of the nozzle openings 21, 21, 21, ...
2, 22, 22, ..., Pressure generating chambers 50, 50, 50, ..., 51, which face the through holes 8 and 9 of the cover plate 7 and the through holes 16 and 17 of the ink flow path forming plate 15, respectively. 51, 51
It is communicated with.

Each of these members 1, 7, 15 and 20 is laminated and joined by a joining method suitable for the material of which it is made, and is assembled into an ink jet recording head.

FIG. 3 shows the surface structure of the above-described piezoelectric vibrators 6, 6, 6, ... Built on the surface of the vibration plate 5, and reference numerals 30, 30, 30 ,. Are drive electrodes formed facing the pressure generating chambers 50, 50, 50, ... In one row, and 31, 31, 31, ... Are opposed to the pressure generating chambers 51, 51, 51. The drive electrodes formed by the above are formed in a rectangular shape so as to have a certain distance from the common electrode lead-out electrode 32a located in the center and the other end to be located near the end of the diaphragm 5. There is.

Reference numeral 32 denotes the above-mentioned common electrode extraction electrode, which is located between the two rows of nozzle openings 21, 21, 21 ... And the nozzle openings 22, 22, 22. , 30, 30, ..., 31, 31, 31, 31 ... Extending in the arrangement direction, and a portion 32 orthogonal to this.
and b.

Of these electrodes, the piezoelectric vibrator 6,
The drive electrodes 30 and 31, which come into contact with the electrodes 6, 6, and the common electrode lead-out electrode 32a exhibit a strong bonding force to both the vibrating plate 5 and the piezoelectric vibrator 6, and also have a conductive material such as platinum. It is formed by vapor deposition or sputtering of platinum alloy or the like.

The surfaces of the drive electrodes 30 and 31 are shaped so as to be continuous with the ones that are immediately opposite to each other, and have a width that covers the side ends of the drive electrodes 30 and 31. A piezoelectric vibrator 6 having a length extending from the outer end of the pressure generating chamber of one row to the outer end of the pressure generating chamber of the other row;
6 (areas indicated by cross hatching in the figure) are provided.

Reference numeral 33 is a common electrode, which is a piezoelectric vibrator 6, 6,
It is provided by vapor-depositing a conductive material or forming a thick film on a region closer to the center than the side ends 6d and 6e (FIG. 3) of 6 and covering the common electrode lead electrode 32.

In this embodiment, when a drive signal is applied to the common electrode 33 and one drive electrode 30, the piezoelectric vibrator 6
Deforms the diaphragm 5 to the pressure generating chamber side by bending only the half region 6a where these electrodes overlap with each other in the width direction with the longitudinal direction as the axis. That is, since the piezoelectric vibrator 6 is electrically separated into two so as to sandwich the nozzle opening rows 21 and 22, only one region is curved.

Since the vibrator 6 has the full width of the common electrode lead-out electrode 32a on the nozzle opening side and the working area fixed to the diaphragm 5 via the drive electrodes 30 and 31, it is sufficient for the diaphragm 5. It is possible to transmit various displacements.

As a result, the volume of the pressure generating chamber 50 is reduced, and the pressure is applied to the ink existing therein. The ink in the pressure generating chamber 50 flows from the through hole 8 of the lid plate 7 through the through hole 16 of the ink supply flow path forming plate 15 into the nozzle opening 21 of the nozzle plate 20, and then ejects as an ink droplet from there.

The application of the drive signal is released and the piezoelectric vibrator 6
When the first half 6a returns to the original shape, the volume of the pressure generating chamber 50 expands and a negative pressure is generated in the pressure generating chamber 50. As a result, ink corresponding to the consumed amount is replenished from the reservoir 10 to the pressure generating chamber 50 through the through hole 12 of the cover plate 7.

The piezoelectric vibrator 6 continuously covers the two pressure generating chambers 50 and 51 facing each other, and there is no cut on the nozzle opening side, and the surface and the side surface are covered with the common electrode 33. Therefore, invasion of moisture in the environment is prevented, and deterioration does not occur even in long-term use.

Further, although not directly contributing to ink ejection, the central portion 6c of the piezoelectric vibrator 6 is also provided in the vicinity of the nozzle opening.
Is fixed to the diaphragm 5, this portion is reinforced, and factors such as crosstalk that deteriorate print quality can be reduced.

Next, a method of manufacturing the above-described recording head will be described with reference to FIG.
It will be described based on. Pressure generation chambers 50, 5 when fired
1, a ceramic material having a thickness suitable for forming No. 1, a zirconia clay thin plate in this embodiment, a so-called green sheet, is punched at a position where a pressure generating chamber is to be formed by a press, and the through holes 3, 3, 3 are formed. ... 4, 4, 4, ...
A first sheet having the holes is prepared. Similarly, a zirconia green sheet having a thickness suitable for the diaphragm 5 is prepared.

The first sheet and the second sheet are laminated, and uniform pressure is applied to dry the two sheets in a state of being adhered. By this drying step, the two sheets are temporarily adhered to each other to be in a semi-solidified state. Then temperature, eg 1000 ° C
Then, it is fired while applying a pressure to prevent warpage. As a result, the respective sheets become ceramics and, at the same time, the two sheets are integrally joined at the boundary surface of the respective sheets by the sintering action as if they were originally composed of one sheet.

Patterns 55, 55, 55 extending from the opposite ends of the pressure generating chambers 50, 51 toward the side ends of the diaphragm 5 on the surface of the member thus constructed which becomes the diaphragm 5.
, 56, 56, 56, and the like, which are electrically conductive and have a high bonding force when firing the diaphragm 5 and a green sheet of a piezoelectric material described later, such as platinum, a platinum-based alloy, or silver. , A silver-based alloy material is used by applying a conductive pattern forming technique such as vapor deposition, sputtering, or screen printing.

At the same time, these drive electrode patterns 55, 5 are formed.
In accordance with the formation of 6, the common electrode extraction electrode pattern 57a and the external connection pattern 57b are provided in the center of the opposite sides of these patterns and are electrically conductive, and the vibration plate 5 is provided.
And a high material that exhibits a strong bonding force when firing a green sheet of a piezoelectric material described later, such as platinum or a platinum-based alloy,
It is formed by using a conductive pattern forming technique such as vapor deposition, sputtering, screen printing or the like using a material of silver or a silver-based alloy (FIG. 5A).

The patterns 55, 56, 57 of these electrodes
When a and 57b are formed, they are slightly larger than the widths of the drive electrode patterns 55 and 56, and face each other across the common electrode extraction electrode pattern 57a from the vicinity of the side end of one drive electrode pattern 55. The pattern 58 of the piezoelectric material that continuously extends to the vicinity of the side end of the pattern 56 on the side where
A green sheet suitable for a vibrator is formed by a thick film printing method using a template or the like (FIG. 5B). Examples of this piezoelectric material include lead zirconate titanate (PZ
T) and the like are desirable.

Even when printing a thick film of this piezoelectric material, two piezoelectric vibrators that drive two pressure generating chambers facing each other are
Since printing is performed through one continuous window, it is possible to press the electrode pattern uniformly, as compared with the case where an individual window is provided for each pressure generating chamber.

When the piezoelectric material reaches a predetermined dryness,
The piezoelectric material is heated at a temperature suitable for firing, for example, about 1000 to 1200 ° C. Even in the firing process, the piezoelectric material is not separated on the opposite side, and is pressed against the common electrode extraction electrode pattern 57a made of a material having a high bonding property, which is continuous, so that the tip portion is different from the conventional case. It does not turn up.

When the firing of the piezoelectric material is completed,
A conductive pattern 59 that covers the vicinity of both ends of each piezoelectric vibrator and the common electrode lead-out layer is formed by sequentially forming a layer of a conductive material, copper, and nickel by film forming means such as vapor deposition, and The electrodes are formed (FIG. 5C). Of course, the patterns 55 and 56 of the drive electrodes are the pattern 5 that becomes the piezoelectric vibrator in the region other than the side end that becomes the external connection portion.
Since it is covered with Nos. 5 and 56, no short circuit with the common electrode 59 occurs.

As a result, as shown in FIG. 6, the piezoelectric vibrator 58 formed so as to be continuous with the conductive patterns 55 and 56 of the two drive electrodes straddles the common electrode extraction electrode 57a at the center thereof. It will be formed and will be fixed to the diaphragm 5 with a large joining force.

In the above-mentioned embodiment, the case where the nozzle openings to be assembled are arranged in a staggered manner has been described as an example. However, for nozzles having nozzle nozzle openings to be assembled on the same line, As shown in the figure, the drive electrodes 61 are arranged so as to face each other so that the common electrode extraction electrode 32a formed in the center of the surface of the diaphragm 5 is a line object.
It is obvious that the strip-shaped piezoelectric vibrators 64, 64, 64 may be arranged so as to straddle the common electrode extraction electrode 32a so as to connect 61, 61, ... And 62, 62, 62. is there. Note that reference numeral 65 in the figure denotes a common electrode formed on the surface of the piezoelectric vibrators 64, 64, 64.

Although the actuator member is divided into three parts, it is obvious that the same effect can be obtained by forming the actuator member on one diaphragm.

Further, in the above-described embodiment, the piezoelectric vibrator is built with the vibrating plate and the spacer member integrated, but the piezoelectric vibrating plate can be built with the vibrating plate alone.

[0036]

As described above, according to the present invention, even an extremely small piezoelectric vibrator can be reliably bonded to the vibration plate, and the piezoelectric vibrator is provided in the area facing the nozzle opening. In addition, since the piezoelectric vibrator is continuous, there is no break in the piezoelectric vibrator near the nozzle opening, which not only prevents deterioration due to ingress of moisture, but this portion also serves as a reinforcing material for the diaphragm. Also works and can improve reliability.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing an embodiment of the present invention.

FIG. 3 is an exploded perspective view showing an example of a drive unit.

FIG. 4 is a top view showing an example of a drive unit.

5A, 5B and 5C are views showing a manufacturing process of the above drive unit.

6 (a), (b), and (c) are diagrams showing the relationship between the central common electrode extraction electrode, the piezoelectric vibrator, and the drive electrode, respectively. FIG. 6 (a) is a top view, (B) is a sectional view taken along the line A-A, and (c) is a sectional view taken along the line BB.

FIG. 7 is a top view showing another embodiment of the present invention.

FIG. 8 is a sectional view showing a piezoelectric vibrator tip region of an actuator using a conventional piezoelectric vibrator.

[Explanation of symbols]

1 drive unit 2 spacer 3, 4 through holes forming pressure generating chamber 5 diaphragm 6 Piezoelectric vibrator 7 Lid plate 8, 9 through holes 10, 11 through holes forming a reservoir 12, 13 through holes 15 Ink supply flow path constituent plate 16, 17 through holes 20 nozzle plate 21,22 nozzle opening 30, 31 Drive electrode 33 Common electrode

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (8)

(57) [Claims] 1. A plurality of which a plurality of nozzle openings in a row
A nozzle opening row of the communicating with the nozzle openings, and a common vibration plate and sealed the pressure generating chamber at regular intervals by arranging parallel to the passage component, wherein The first formed on the vibration plate corresponding to the pressure generating chamber
Of the electrode, a second electrode formed on the surface of the diaphragm at the center of the region on the opposite side of each nozzle opening row, and one of the first electrodes facing each other with the second electrode interposed therebetween. A piezoelectric vibrator formed so as to be continuous from the vicinity of the other end to the vicinity of the other end of the other first electrode, and formed on the surface of the piezoelectric vibrator.
A third electrode that is electrically connected to the first electrode and the third electrode.
A laminated-type ink jet recording head comprising: a piezoelectric driving unit including a piezoelectric vibrator having a region sandwiched by a pole as a displacement region . 2. The third electrode is in contact with the second electrode.
The laminated ink jet recording head according to claim 1, which is continued . 3. The flow path forming member includes a diaphragm made of an insulating material, a spacer member having through holes forming pressure generating chambers formed in two rows and one set, and the other of the spacer members. A lid plate having a through hole that communicates the reservoir and the pressure generating chamber, and the nozzle opening and the pressure generating chamber, is connected to the ink tank and communicates with the nozzle opening and the pressure generating chamber. 2. The laminated ink jet recording head according to claim 1, which is configured by laminating an ink supply member having a through hole and a through hole forming the reservoir, and a nozzle plate having a nozzle opening. 4. The ink jet recording according to claim 1, wherein the vibrating plate is made of zirconia, and each electrode formed on the surface of the vibrating plate is platinum, platinum-based alloy, silver or silver-based alloy. head. 5. The ink jet recording head according to claim 1, wherein the vibrating plate and the spacer member are made of ceramic. 6. The nozzle opening is made of a material selected from platinum, a platinum-based alloy, silver, and a silver-based alloy that has a conductive property and exhibits a strong bonding force between the material forming the diaphragm and the piezoelectric material. Forming a pair of first electrodes in two rows and facing each other, and a step of forming a pattern of the second electrode between the first electrode rows, and slightly larger than the pattern of the first electrode,
A step of forming a pattern of a piezoelectric material continuously extending from the vicinity of one side edge of the pattern of the first electrode to the vicinity of the side edge of the pattern of the first electrode on the opposite side across the pattern of the second electrode. And a step of firing the piezoelectric material, and a method for manufacturing a drive body for an inkjet recording head. 7. A spacer member for forming an ink flow path is previously fixed to the vibration plate so as to be integrated with the vibration plate.
And a method for manufacturing a driving body for an inkjet recording head. 8. The vibrating plate is ceramic.
And a method for manufacturing a driving body for an inkjet recording head.