JPH08127124A - Ink jet recording head - Google Patents

Abstract

PURPOSE: To enable miniaturization and the densification of nozzles. CONSTITUTION: Grooves 301, recessed pressure chambers 303 and grooves 302 are formed on the surface of a substrate member 3 so as to be arranged side by side at a predetermined interval. A vibration plate 4 is closely bonded and fixed to the upper surface of the substrate member 3 and nozzles 304 are formed to the leading ends of the grooves 301 by this vibration plate 4. Each of piezoelectric members 1 is constituted of a central drive part 103 wherein electrodes 102a, 102b are arranged on the upper and rear surfaces of thin plate-shaped piezoelectric elements 101 in opposed relationship, one non-drive part 104 having only the electrodes 102b arranged thereto and other non-drive part 105 having only the electrodes 102a arranged thereto and the drive part 103 is positionally set so as to be opposed to the almost central part of each of the pressure chambers 303 to be closely bonded and fixed to the vibration plate 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head of an ink jet recording apparatus applied to facsimiles, copying machines, printers and the like.

[0002]

2. Description of the Related Art In recent years, an ink jet recording apparatus for ejecting ink from a nozzle of an ink jet recording head to print on paper has been put into practical use. In an ink jet recording head used in this type of recording apparatus, a piezoelectric element is arranged in close contact with a vibrating plate forming one surface of a pressure chamber, and the piezoelectric element is deformed by voltage application to cause the vibrating plate to absorb ink in the pressure chamber. When pressed, ink is ejected from the nozzle communicating with the pressurizing chamber. Heretofore, various proposals have been made regarding a mounting structure of a piezoelectric element of an ink jet recording head (JP-A-60-90770 and JP-A-3-10846).

In the ink jet recording head described in JP-A-60-90770, a piezoelectric element is laminated on the surface of a vibrating plate facing the pressure chamber of the head body, and the piezoelectric element is attached to the head body by a rigid member. Holds rigidly. This rigid member ensures that the deformation of the piezoelectric element is transmitted to the diaphragm.

Further, in the ink jet recording head described in JP-A-3-10846, the laminated piezoelectric element laminated on the surface of the vibrating plate is partitioned by a groove, and a driving portion facing the pressurizing chamber and an additional portion. The holding portions facing each other are alternately arranged between the pressure chambers. By adopting the piezoelectric element having this structure, it is not necessary to provide a single piezoelectric element for each pressurizing chamber, and the mounting work is facilitated, so that the manufacturing efficiency of the head is improved.

[0005]

However, in the ink jet recording head described in JP-A-60-90770, it is difficult to miniaturize the ink jet recording head because the rigid member is provided separately from the piezoelectric element.

Further, in the ink jet recording head described in JP-A-3-10846, since the holding portion is not used as a drive source, the arrangement interval of the drive portion becomes twice as large as it should be, and therefore the pressurizing chamber facing the same. Also, since the interval between the nozzles is doubled, it is difficult to increase the density of the nozzles.

An object of the present invention is to solve the above problems and to provide an ink jet recording head which can be downsized and the density of nozzles can be increased.

[0008]

In order to achieve the above object, the present invention comprises a substrate and a vibrating plate which is in close contact with and fixed to the substrate, and forms a nozzle and an ink pressurizing chamber communicating with the nozzle. In the ink jet recording head, the piezoelectric member is fixed at a position facing the pressure chamber of the vibration plate, and a piezoelectric member having electrodes arranged on both surfaces is provided. The driving unit is arranged to face each other, and the non-driving unit in which electrodes are not arranged to face each other on both sides of the driving unit, and the driving unit faces the pressurizing chamber. The position is set (Claim 1).

In the head member, a plurality of nozzles and pressure chambers are formed side by side at predetermined intervals in one direction, and in the piezoelectric member, the driving portion and the non-driving portion are orthogonal to each other in the one direction. They are arranged in the direction in which they are aligned (claim 2).

The piezoelectric member is formed by laminating a plurality of thin plate-shaped piezoelectric elements, and the piezoelectric elements are in a laminated state.
A drive section in which electrodes are arranged to face each other and a non-drive section in which electrodes are not arranged to face each other are formed on both surfaces (claim 3).

The piezoelectric member has a thin plate-shaped first piezoelectric element in which electrodes are provided on the upper surface except for one end portion and electrodes are provided on the lower surface except for the other end portion, and on the upper surface. A thin plate-shaped second piezoelectric element in which an electrode is provided except for the other end and an electrode is provided on the lower surface except for the one end is alternately laminated. (Claim 4).

[0012]

According to the invention described in claim 1, when a voltage is applied between the electrodes of the piezoelectric member, the driving portion is deformed. On the other hand, since the electrodes are not arranged to face the non-driving portion of the piezoelectric member, no electric field is generated and no deformation occurs. Therefore,
The piezoelectric member is supported by the non-driving portions on both sides of the driving portion and is securely fixed to the diaphragm.

According to the second aspect of the present invention, since the direction in which the driving portion and the non-driving portion are arranged is orthogonal to the direction in which the plurality of pressurizing chambers are arranged, the width of the pressurizing chamber and the Even if the distance is reduced, there is no problem such as the non-driving portion coming into contact with the adjacent piezoelectric member. Further, in order to more securely fix the piezoelectric member to the vibration plate, even if the size of the piezoelectric member is increased and the area of the non-driving portion is increased to increase the contact area of the non-driving portion and the vibration plate, the adjacent piezoelectric member is There is no problem such as contact with the non-driving part.

According to the third aspect of the invention, since the thin plate-shaped piezoelectric element is used, the electrode interval is short, and therefore the electric field hardly leaks from the driving part to the non-driving part. Therefore, the deformation of the non-driving portion is reliably prevented, and the piezoelectric member is more reliably fixed to the substrate by the non-driving portion.

According to the fourth aspect of the invention, since the thin plate-shaped piezoelectric element is used, the electrode interval is short, so that the electric field hardly leaks to the one end and the other end. Therefore, when a voltage is applied between the electrodes of the piezoelectric element, the one end and the other end are securely prevented from being deformed. Fixed to the substrate.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ink jet recording head according to the present invention will be described with reference to the drawings. FIG.
(A) is a front view of the same Example, (b) is a BB sectional view of (a).

This ink jet recording head is composed of a piezoelectric member 1, a holding member 2, a substrate member 3 and a vibrating plate 4. The piezoelectric member 1 has electrodes 102a, 10 on the upper and lower surfaces.
It is formed by stacking thin plate-shaped piezoelectric elements 101 on which 2b are arranged. For convenience of explanation, the electrodes 102a and 102b are not shown in FIG. 1A, and the boundaries between the piezoelectric elements 101 are not shown in FIG. 1B.

The holding member 2 is a plate having a constant thickness,
It has a required rigidity and transmits almost all the deformation occurring in the piezoelectric member 1 to the diaphragm 4 side.

The substrate member 3 is, for example, a plate-like body made of glass or the like having a required thickness, and on its surface, a groove 301 having a small cross-sectional area which communicates from the left end to the right end in FIG. A concave pressure chamber 303 and a groove 302 having the same shape as the groove 301 are formed. Further, the groove 301, the pressurizing chamber 303, and the groove 302 are formed side by side at a predetermined interval in the left-right direction in FIG. The vibrating plate 4 is a thin plate made of glass, for example, and is closely attached and fixed to the upper surface of the substrate member 3, and covers the groove 301, the pressure chamber 303, and the groove 302 to form an ink flow path.

By the substrate member 3 and the vibrating plate 4, the groove 3 is formed.
A nozzle 304 is formed at the tip of 01. Pressure chamber 3
Reference numeral 03 denotes a substantially rectangular parallelepiped recess, which deforms the vibrating plate 4 downward by the deformation of the piezoelectric member 1 as described later, thereby pressurizing the ink filled in the inside to generate the nozzle 30.
4 is to eject ink. Also, the groove 302
Is connected to an ink cartridge (not shown), and ink is supplied to the pressure chamber 303.

The piezoelectric element 101 is made of a piezoelectric material such as lead zirconate titanate (PZT) and is polarized in the thickness direction. Then, as shown in FIG. 1B, the piezoelectric member 1 has electrodes 102a, 1 on the upper and lower surfaces of each piezoelectric element 101.
02b facing each other, a central driving unit 103, a non-driving unit 104 on one side where only the electrode 102b is arranged, and a non-driving unit 105 on the other side where only the electrode 102a is arranged.
Are formed. Then, the drive unit 103 causes the pressurizing chamber 30
It is positioned so as to face substantially the center of 3, and the upper surface is fixed to the holding member 2 and the lower surface is fixed to the vibration plate 4, respectively. The piezoelectric members 1 are formed side by side at the same intervals as the pressurizing chamber 303 in the left-right direction of FIG.

Further, between the electrodes 102a and 102b,
A power source (not shown) is connected via a wiring (not shown).
This power supply selectively applies a voltage of a predetermined level between the electrodes 102a and 102b of each piezoelectric member 1 to cause deformation of each corresponding piezoelectric member 1.

Next, an example of the manufacturing procedure of this ink jet recording head will be described with reference to FIGS. FIG. 2 is a diagram for explaining the procedure for producing the piezoelectric base material, and FIG. 3 is a flowchart showing the procedure. FIG. 4A is a front view of the piezoelectric base material fixed to the holding member, and FIG. 4B is a side view of FIG. Note that, in FIG. 2, for convenience of description, the vertical direction is shown in an enlarged manner compared to the horizontal direction. Further, in FIG. 4A, the electrodes 102a and 102b are omitted, and in FIG. 4B, the boundaries between the piezoelectric elements 101 are omitted.

First, the production of the piezoelectric base material 1A is shown in FIG.
This will be described with reference to FIG. First, lead titanate (PbTi
O ₃ ), lead zirconate (PbZrO ₃ ) and a binder are kneaded to form a PZT material (step S1), and the piezoelectric element 101 is formed by screen printing (step S).
2).

Next, a thin-film electrode 102a is formed on the upper surface of the piezoelectric element 101 by screen printing a metal such as aluminum except the left end portion (step S).
3). Next, if the stacking of the piezoelectric element 101 is not completed (NO in step S4), the process returns to step S2, the piezoelectric element 101 is formed, and the electrode 102b is formed (steps S2 and S3). The electrode 102b is formed except for the right end portion. In this way, steps S2 and S3 are repeated to stack the PZT material and the electrodes. The piezoelectric element 101 preferably has the same rectangular surface. The quadrangular shape has a length that is equal to or greater than the length of the pressure chamber 303 and a width that is equal to or greater than the width of the plurality of pressure chambers 303.

When the lamination of the piezoelectric element 101 is completed (YES in step S4), the piezoelectric element 1A is pressed with high pressure (step S5), pre-baked (step S6), and baked (step S7). The production is completed. As a result, in the piezoelectric base material 1A, the central drive unit 103 in which the electrodes 102a and 102b are disposed so as to face each other, the non-drive unit 104 in which only the electrode 102b is disposed, and the non-drive unit in which only the electrode 102a is disposed. The driving unit 105 is formed. The adjacent piezoelectric elements 101 are polarized so that their polarization directions are opposite to each other.

Next, as shown in FIG. 4, the piezoelectric base material 1A is adhered and fixed to the lower surface of the holding member 2 by adhesion or the like. Then, as shown in FIG. 5, slits are formed in a comb-like shape by cutting or the like in the stacking direction of the piezoelectric elements 101 so that the width is almost the same as that of the pressure chamber 303 at the same interval as the pressure chamber 303. To form the piezoelectric member 1.

Then, as shown in FIG. 1, the piezoelectric member 1 thus manufactured is positioned on the vibrating plate 4 fixed to the substrate member 3 by positioning the piezoelectric member 1 so as to face the pressurizing chamber 303. An ink jet recording head is constructed by adhesion and fixing.

Next, the operation of the ink jet recording head configured as described above will be described. Electrode 10
When an output voltage from the power supply is applied between 2a and 102b, the driving unit 103 of the piezoelectric member 1 is deformed to the pressurizing chamber 303 side as shown in FIG.
The ink inside is pressurized, and the ink is ejected from the nozzle 304.

At this time, the non-driving portion 104 of the piezoelectric member 1,
In No. 105, since no electric field is generated in the stacking direction, electrostriction does not occur and deformation does not occur. This non-driving unit 10
Reference numerals 4 and 105 act as supporting portions of the piezoelectric member 1.

As described above, the non-driving portions 104 and 105 formed on both sides of the driving portion 103 by a required width are provided with the pressurizing chamber 303.
By arranging the piezoelectric member 1 in the front and rear, the piezoelectric member 1 can be reliably fixed to the diaphragm 4 by utilizing a part of the piezoelectric member 1 itself.
Therefore, it is not necessary to separately provide a supporting member for fixing the piezoelectric member 1, so that the inkjet recording head can be downsized.

Further, since the width and the interval of the piezoelectric member 1 can be freely made by the width and the interval of the slit formed in the piezoelectric base material 1A, the pressurizing chamber 303 and the nozzle 304 are provided.
The arrangement interval of can be made smaller and can be arranged at high density.

Further, the piezoelectric member 1 is replaced by a thin plate-shaped piezoelectric element 1
01 is laminated to form electrodes 102a and 102b.
Can be shortened, the drive unit 103 to the non-drive unit 104,
The leakage electric field to 105 can be almost eliminated. Therefore, since the non-driving portions 104 and 105 can be reliably prevented from being deformed, the piezoelectric member 1 can be more reliably fixed to the diaphragm 4.

Further, since the amount of deformation of the piezoelectric element 101 is proportional to the internal electric field strength, the voltage applied between the electrodes 102a and 102b can be made low by making each piezoelectric element 101 a thin plate. Even in this case, the piezoelectric element 10
Since the piezoelectric members 1 are formed by laminating the piezoelectric members 1, it is possible to secure a required amount of deformation in the entire piezoelectric member 1.

The piezoelectric base material 1A forming the piezoelectric member 1
Is not limited to the structure shown in FIG. 2, but may be the structure shown in FIGS.

In FIG. 6, thin film electrodes 102a and 102b are provided on the upper and lower surfaces of the piezoelectric element 101 by vapor deposition or sputtering of a metal such as aluminum.
At this time, the electrode 102a is arranged excluding the left end portion, and the electrode 102b is arranged excluding the right end portion. Further, the insulating film 106 is formed on the lower surface. After this, the piezoelectric element 101
Are laminated by a required number of sheets and fixed to each other by adhesion or the like to produce the piezoelectric base material 1A.

In FIG. 7, thin film electrodes 102a and 102b are provided on the upper and lower surfaces of the piezoelectric elements 101a and 101b by vapor deposition or sputtering of a metal such as aluminum. Here, the piezoelectric element 101 a includes the electrode 102.
a is provided except for the left end of the upper surface, and the electrode 102b is provided except for the right end of the lower surface. On the other hand, the piezoelectric element 1
In 01b, the electrode 102b is arranged except for the right end of the upper surface, and the electrode 102a is arranged except for the left end of the lower surface. Then, the piezoelectric elements 101a and 101b are alternately laminated and fixed to each other by adhesion or the like to manufacture the piezoelectric base material 1A. The piezoelectric elements 101a and 101b are arranged so that their polarization directions are opposite to each other.

In FIG. 8, thin film electrodes 102a and 102b are provided on the upper surfaces of the piezoelectric elements 101c and 101d by vapor deposition or sputtering of a metal such as aluminum. Here, the piezoelectric element 101c includes the electrode 102a.
Is provided except for the left end portion, and the piezoelectric element 101d is provided with the electrode 102b except for the right end portion. Then, the piezoelectric elements 101c and 101d are alternately laminated and fixed to each other by adhesion or the like to manufacture the piezoelectric base material 1A. In addition,
The piezoelectric elements 101c and 101d are arranged such that their polarization directions are opposite to each other.

In the configurations of FIGS. 6 to 8 also, the electrodes 102a, 1
02b facing each other, a central driving unit 103, a non-driving unit 104 only having an electrode 102b, and an electrode 10.
A non-driving portion 105 in which only 2a is arranged is formed. Therefore, the same effect as in the case of FIG. 2 is obtained.

The piezoelectric member 1 may be a plate-shaped one-piece piezoelectric element having a required thickness.
Even in this case, one electrode is arranged excluding one end of the upper surface of the piezoelectric element, and the other electrode is arranged excluding the other end of the lower surface, so that it does not deform even when a voltage is applied. If the non-driving portions are formed on both sides, similarly, the piezoelectric member 1 can be securely fixed to the diaphragm 4.

[0041]

As described above, according to the first aspect of the invention, the piezoelectric member is provided with the drive section in which the electrodes are arranged so as to face each other, and the electrodes are arranged so as to face each other on both sides of the drive section. Since it is configured with a non-driving portion which is not formed, and the driving portion is positioned so as to face the pressurizing chamber and is fixed to the diaphragm, by supporting the non-driving portion that is not deformed by voltage application, The piezoelectric member can be securely fixed to the diaphragm.

Further, according to the invention of claim 2, the direction in which the driving portion and the non-driving portion are lined up is orthogonal to the direction in which the plurality of pressurizing chambers are lined up. The piezoelectric member can be formed corresponding to the above. Therefore, the nozzles can be arranged at high density. Further, the area of the non-driving portion can be increased by enlarging the piezoelectric member without disturbing the adjacent piezoelectric members. Therefore, by increasing the contact area between the non-driving portion and the diaphragm, the piezoelectric member can be more reliably fixed to the diaphragm.

According to the third aspect of the invention, since the piezoelectric member is formed by laminating thin plate-shaped piezoelectric elements, since the electrode interval is short, an electric field is almost generated from the driving part to the non-driving part. Since it does not leak, deformation of the non-driving portion can be reliably prevented. Therefore, the piezoelectric member can be more reliably fixed to the diaphragm.

According to the fourth aspect of the invention, the piezoelectric member has a thin plate-like shape in which electrodes are provided on the upper surface except for one end and electrodes are provided on the lower surface except for the other end. An electrode is provided on the upper surface of the first piezoelectric element except for the other end portion,
Since the thin plate-shaped second piezoelectric elements in which electrodes are provided except for the one end portion are formed alternately on the lower surface, the electrode interval is short, so that one end portion from the drive portion Since the electric field hardly leaks to the other end, it is possible to reliably prevent the deformation of the one end and the other end. Therefore, by supporting the one end and the other end, the piezoelectric member can be more reliably fixed to the diaphragm.

[Brief description of drawings]

FIG. 1A is a front view of an embodiment of an inkjet recording head according to the present invention, and FIG. 1B is a sectional view taken along line BB of FIG.

FIG. 2 is a diagram illustrating a procedure for manufacturing a piezoelectric base material.

FIG. 3 is a flowchart showing a procedure for producing a piezoelectric base material.

FIG. 4A is a front view of a piezoelectric base material fixed to a holding member, and FIG. 4B is a side view of FIG.

FIG. 5 is a front view of a piezoelectric member having slits formed by cutting.

FIG. 6 is an explanatory diagram showing a different configuration example of the piezoelectric base material.

FIG. 7 is an explanatory diagram showing a different configuration example of the piezoelectric base material.

FIG. 8 is an explanatory diagram showing a different configuration example of the piezoelectric base material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric member 1A Piezoelectric base material 101 Piezoelectric element 102a, 102b Electrode 103 Driving part 104, 105 Non-driving part 106 Insulating film 2 Holding member 3 Substrate member 301, 302 Groove 303 Pressurizing chamber 304 Nozzle 4 Vibration plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Watanabe 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Setsuo Hori 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Within Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A head member comprising a substrate and a vibrating plate closely fixed to the substrate, in which a nozzle and a pressure chamber for ink communicating with the nozzle are formed, and a head member facing the pressure chamber of the vibrating plate. In an ink jet recording head including a piezoelectric member fixed at a position where electrodes are provided on both sides, the piezoelectric member includes a drive unit in which electrodes on both sides are arranged facing each other and both sides of the drive unit. The inkjet recording head is characterized in that the electrodes are formed so as not to face each other and the driving unit is positioned so as to face the pressurizing chamber. 2. The head member has a plurality of nozzles and a pressurizing chamber formed side by side at predetermined intervals in one direction, and the piezoelectric member has the driving portion and the non-driving portion orthogonal to the one direction. The ink jet recording head according to claim 1, wherein the ink jet recording heads are arranged in a direction in which the ink jet recording head is aligned. 3. The piezoelectric member is formed by laminating a plurality of thin plate-shaped piezoelectric elements, and the piezoelectric elements are arranged in a laminated state such that the electrodes are opposed to a drive section in which electrodes are arranged on both sides of the piezoelectric element. 3. The ink jet recording head according to claim 1 or 2, wherein a non-driving portion which is not disposed is formed. 4. The piezoelectric member is a thin plate-shaped first piezoelectric element in which an electrode is provided on an upper surface except for one end portion, and an electrode is provided on a lower surface except for the other end portion, and an upper surface is provided. A thin plate-shaped second piezoelectric element in which an electrode is provided except for the other end and an electrode is provided on the lower surface except for the one end is alternately laminated. The ink jet recording head according to any one of claims 1 to 3, wherein