JP3381790B2 - Pressure generation unit for multilayer inkjet printhead - Google Patents

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 in which a piezoelectric vibrator is attached to a partial region of a pressure chamber communicating with a nozzle opening, and the pressure chamber is compressed by the piezoelectric vibrator to generate ink droplets. The present invention relates to a pressure generating unit.

[0002]

2. Description of the Related Art An ink jet recording head in which a piezoelectric vibrating plate is stretched in a partial area of a vibrating plate which constitutes a pressure chamber and the volume of the pressure chamber is changed by displacement of the piezoelectric vibrating plate to generate ink droplets is known. Since the wide area of the pressure chamber can be displaced, the ink droplets can be stably generated. However, since the ink droplets are ejected in the direction perpendicular to the displacement direction of the diaphragm, the size of the recording paper in the direction perpendicular to the paper surface becomes large, and the carriage and the like become large. In order to solve such a problem, a pressure generating member including a vibrating plate and an ink flow path forming member are configured by a laminated structure, and a nozzle opening is provided in parallel with a displacement direction of the vibrating plate to achieve a thin inkjet printer. A recording head has been proposed (Japanese Patent Laid-Open No. Sho 62).
-111758 publication). With such a laminated structure, not only the size can be reduced, but also a simple method of adhering pressed or etched plate materials can be applied, so that the manufacturing process can be simplified. However, due to the use of adhesives for bonding each plate material, the flow of the adhesive into the minute small holes may lead to a decrease in reliability due to fluctuations in the flow path resistance, and the attachment of the piezoelectric vibrator to the diaphragm. However, since it relies on adhesives, etching and laser processing, it has a problem that it takes time.
In order to solve such a problem, a semi-solidified ceramic plate is processed into a required shape to form a flow path member and a piezoelectric vibrator, and these are stacked and fired to attach the piezoelectric vibrator. An inkjet recording head that does not require work has also been proposed (Japanese Patent Laid-Open No. 63-149159).
However, this is one in which the nozzle openings are provided in the direction perpendicular to the displacement direction of the vibration plate as described above, and this cannot be applied to thin the recording head.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of these problems, and an object of the present invention is to provide a laminated type ink jet recording head which can be thinned and has a good assembly accuracy. It is to provide a suitable pressure generating unit.

[0004]

In order to solve such a problem, in the present invention, a pressure chamber forming member having a plurality of through holes forming a pressure chamber and a surface facing the pressure chamber.
An electrode extending from the position to the end region, a plate member that forms a piezoelectric vibrator on the surface of the electrode to seal one surface of the pressure chamber forming member, and a connection flow path between the reservoir and the pressure chamber. It is formed by laminating a through hole to be formed and a through hole connecting the pressure chamber and the nozzle opening, and a lid member for sealing the other surface of the pressure chamber forming member.

[0005]

[Operation] Since it can be supplied as a separate member from the flow path unit,
The yield can be improved by manufacturing in an environment suitable for forming the piezoelectric elements and electrodes, and the recording head can be configured by a simple operation of joining to the flow path unit.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. 1 and 2 are a sectional view showing an embodiment of the present invention and an exploded perspective view thereof, in which reference numeral 1 indicates
With the pressure chamber forming member, a thickness suitable for forming the pressure chamber,
For example, as shown in an enlarged view in FIG. 4, a ceramic plate made of zirconia (ZrO2) or the like having a diameter of 150 μm is formed into a long round rectangular pressure chamber 2, 2, 2, ...
The shape of the reservoir 2 and one end of the reservoir 2 as shown in FIG.
1 and the other end thereof overlaps with the nozzle opening 31 and is formed at a constant pitch. Reference numeral 4 denotes a vibrating plate fixed to one surface of the pressure chamber forming member 1, which is a material having a good compatibility when fired together with the pressure chamber forming member 1 and having a high elastic modulus. Similarly, a zirconia thin plate having a thickness of 10 μm is formed, and the surface thereof has a drive signal applying electrode 5 of the piezoelectric vibrator 7 corresponding to the pressure chamber 2 as shown in FIG.
The extraction electrode 6 of a common electrode described later is provided.

Reference numeral 7 denotes the above-described piezoelectric vibrator, which covers the drive signal applying electrode 5 and is substantially equal to the length of the pressure chamber 2 in the longitudinal direction as shown in FIG. 4 and has a small width such as PZT. It is made of a thin plate of a vibrating material, and is configured to vibrate in a mode of bending in the width direction with the longitudinal direction as an axis. The common electrodes 8 are formed on the surfaces of the piezoelectric vibrators 7, 7, 7, ... And the extraction electrode 6 by a film forming method such as sputtering as shown in FIGS. As a result, in each piezoelectric vibrator 7, the vibrating plate 4 side is connected to the drive signal applying electrode 5, and the front surface side is connected to the common electrode 8. Further, as shown in FIG. 6, the piezoelectric vibrator 7 is formed so as to be wider than the width of the drive signal applying electrode 5 and slightly project from both ends in the width direction by W and W ′, respectively.

Reference numeral 10 denotes a lid member which cooperates with the vibration plate 4 to form the pressure chamber 2, and is a material having a good compatibility when fired together with the pressure chamber forming member 1. In this embodiment, a thin plate of zirconia having a thickness of 150 μm. And a through hole 11 connecting a nozzle opening 31 and the pressure chamber 2 described later, a reservoir 21 and the pressure chamber 2.
Is formed by forming a through hole 12 for connecting to each other. Each of these members 1, 4, 10 is integrally fixed and assembled as a pressure generating unit 15.

Reference numeral 20 denotes a reservoir forming member constituting the flow passage unit 35, which is a substantially V-shaped member for forming the reservoir 21 on a plate material having corrosion resistance such as 150 μm stainless steel suitable for forming an ink flow passage. Through-hole 21 ',
A through hole 22 serving as a communication path connecting the pressure chamber 2 and the nozzle opening 31.
Is formed by drilling. Through hole 2 which becomes the reservoir 21
Reference numeral 1'denotes each pressure chamber 2, 2, 2 from the ink supply port member 24.
It is configured to extend parallel to the end of. That is, in this embodiment including two rows of nozzle openings,
The ink supply port member 24 is used as a tip to branch in a “V” shape to form a linear flow path from each branch to the pressure chambers 2, 2, 2.

Reference numeral 26 denotes an ink supply member fixed to one of the reservoir forming members 20 described above, and a through hole 27 connecting the pressure chamber 2 and the nozzle opening 31, and a reservoir 21 and the pressure chamber 2.
A through hole 2 for connecting to and is formed, and an ink supply port forming member 24 for connecting to an ink tank (not shown) is fixed to the surface.

Reference numeral 30 denotes a nozzle plate fixed to the other surface of the spacer member, which is made of a stainless steel plate having a thickness of 60 μm suitable for forming a nozzle opening having a diameter of 40 μm, and is located at a position facing the pressure chamber 2. Nozzle openings 31, 31 ...
Is provided. These members 20, 26, 30 are
Each of them is integrally laminated by an adhesive, welding, or the like, and is collected as a flow path unit 35. Since these members 20, 26, 30 are made of metal, even if they have a large through-hole 21 'for forming a reservoir inside, they will dig in or deform even if pressure is applied to obtain sufficient adhesive strength. It is possible to assemble them into layers while maintaining high accuracy and dimensional accuracy without causing any problems.

The pressure generating unit 15 and the flow path unit 35 face each other, that is, the lid member 10.
An adhesive is applied to the contact surface between the ink supply member 26 and the ink supply member 26, and is integrally fixed to form a recording head. This allows
The pressure chamber 2 includes the through hole 12 of the lid member 10 and the ink supply member 2.
6 to the reservoir 21 and the lid member 10
Through the through hole 11 of the ink supply member 26 and the through hole 22 of the reservoir forming member 20.

7 and 8 show the structures of the front side and the back side of the laminated type ink jet recording head of the present invention, respectively, and the nozzle openings 31, 31, 31 ,.
Are arranged in two rows at regular intervals, and the pressure generating unit 1 is integrated with the flow path unit 35 on the back surface side.
5 is fixed, and a cable 37 for transmitting an electric signal is connected to each of the piezoelectric vibrators 7, 7, 7.

In this embodiment, when a drive signal is applied to one of the piezoelectric vibrators 7, the piezoelectric vibrator 7 bends in the width direction with the longitudinal direction as an axis as shown in FIG. To the pressure chamber side. As a result, the volume of the pressure chamber 2 is reduced and pressure is applied to the ink present therein. The ink in the pressure chamber 2 passes through the through hole 11 of the lid member 10.
From the through hole 27 of the ink supply member 26, the flow path unit 35
Through the through hole 22 of the reservoir forming member 20 to the nozzle opening 31 of the nozzle plate 30 and ejects from here as an ink droplet.

By the way, the flow path connecting the pressure chamber 2 and the nozzle opening 31 has through holes 11, 27, 2 formed in the lid member 10, the ink supply member 26, and the reservoir forming member 20.
2, the diameter of the nozzle opening side is gradually reduced, so that it is difficult for bubbles in the pressure chamber to enter the flow path. The ink in the pressure chamber 2 passes through the holes 12, 2
Although it also flows into the reservoir 21 through 8, the diameter of the through hole 28 is small, so there is no pressure loss to the extent that it affects the flight of ink droplets.

The application of the drive signal is released and the piezoelectric vibrator 7
When returns to its original shape, the volume of the pressure chamber 2 expands and a negative pressure is generated in the pressure chamber 2. As a result, ink corresponding to the consumed amount is replenished from the reservoir 21 to the pressure chamber 2 through the through holes 28 and 12. The negative pressure generated in the pressure chamber 2 also acts on the nozzle openings 31, but the nozzle openings 31, 31,
The ink is prevented from retreating to the pressure chamber side due to the meniscus formed in 31 .., and the ink is effectively sucked from the reservoir 21.

Since the flow path unit 35 and the pressure generating unit 15 are connected via a thin layer of a polymer material adhesive having a thickness of about 30 μm, a difference in thermal expansion between the two units occurs due to a temperature change. Even in this case, the difference in thermal expansion is not buffered by the adhesive layer to cause distortion in the nozzle plate, and the adhesive layer prevents deterioration of print quality.

Next, a method of manufacturing the above-described recording head will be described with reference to FIG.
A description will be given based on 0. A ceramic material having a thickness suitable for forming the pressure chamber 2 when fired, in this example, a clay-like thin plate of zirconia, a so-called green sheet 40, is punched at a position where the pressure chamber is to be formed with a press to form a through hole. A first sheet having 41, 41, ... Perforated is prepared. Similarly, a second sheet 42 is prepared by press-forming through holes 43 and 44, which are communication holes between the reservoir 21 and the nozzle openings 31, in a zirconia green sheet having a thickness suitable for forming the lid member 10. .

A second sheet 42 and a third sheet 45 made of a zirconia green sheet having a thickness suitable for the diaphragm 4 are laminated in a sandwich so as to sandwich the first sheet 40, and a uniform pressure is applied. Is added, and the three pieces are dried while being adhered. By this drying process, three sheets 40,
42 and 45 are temporarily adhered to each other to be in a semi-solidified state. Then, it is fired at a temperature of, for example, 1000 ° C. while applying a pressure to prevent warpage. As a result, each sheet changes into ceramics, and at the same time, at the boundary surface of each sheet, the three sheets become integrated as if they were originally composed of one sheet due to the sintering action (FIG. 10I).

Needless to say, even if the first sheet 40 serving as the pressure chamber forming member is provided with the through hole 41 serving as the pressure chamber, the lateral width of the through hole 41 is extremely small, so that temporary bonding is performed. Without causing unnecessary deformation of the third and second sheets 45 and 42 which sometimes become the diaphragm and the lid member, the pressure is appropriately concentrated on the portion of the through hole 41 to form the diaphragm and the lid member. It contributes to the sintering of the sheets 45, 42 into the first sheet 40 and helps to finish the pressure chamber volume as designed.

By firing, the sheets 40, 42 and 45 function as the pressure chamber forming member 50, the lid member 51 and the vibrating plate 52, respectively. In this state, a conductive paste is formed on the surface of the vibration plate 52 at the position of the pressure chamber 53 and at the position of the common electrode lead terminal by the thick film printing method and dried. Then, a clay-like piezoelectric material is thick-film printed using a mask having through holes formed according to the shape of the pressure chamber 53. When the oscillator constituent material is dried to a state suitable for firing, the entire body is heated at a temperature suitable for firing the piezoelectric oscillator and the electrodes, for example, about 1000 to 1200 ° C. As a result, the piezoelectric vibrator 54 can be formed in each pressure chamber 53 (see FIG. 1).
0 II). Then, when the piezoelectric vibrator 54 is formed,
When a layer of a conductive material is formed by a film forming method such as sputtering so as to cover the common electrode lead terminal and the piezoelectric vibrator 54, the diaphragm, the pressure chamber forming member, and the lid member are made of the same material as if they were configured as a block. Complete pressure generation unit.

On the other hand, an ink supply member 60 in which through holes 61 and 62 corresponding to the communication hole 27 and the flow path limiting hole 28 are formed by pressing in a metal plate material having a predetermined thickness, and the reservoir 2
1, a reservoir forming member 66 in which through holes 64 and 65 that will be the communication holes 22 are formed by pressing, and a nozzle plate 69 in which through holes 68 that will be the nozzle openings 31 are formed by pressing are prepared, and shown in FIG. In this way, through holes 70, 70, ...
, 72, ..., 73 are interposed and thermocompression-bonded to form a flow path unit (FIG. 10 III).

As shown in FIG. 12 (a), an adhesive agent is applied to the surface of the ink supply member 60 of one unit, for example, the flow path unit, as shown in FIG. The adhesive layer 80 is applied or formed by a heat-welding film (IV in FIG. 10), and the lid member 51 of the pressure generating unit is attached thereto, and the through holes 56 and 57 are formed.
When they are aligned and joined so that they are positioned concentrically (FIG. 10V), an adhesive layer 81 serving as a cushioning material that absorbs the difference in thermal expansion between different materials is interposed between the flow path unit and the pressure generating unit. The recording head is completed. Since the adhesive layer 80 spreads laterally when pressure is applied from the two members to be joined, a region 82 to which no adhesive is applied is provided on the outer periphery of the through hole so that the cover member 51 and the ink supply member 60 have through holes. It is prevented from flowing.

According to this embodiment, since the pressure generating member is made of ceramics having a lower density than metal, vibrations propagating from adjacent piezoelectric vibrators having a large degree of damping are damped as much as possible. And crosstalk can be prevented. Further, since the members that are constantly deformed by vibration can be integrally configured without interposing a different material in the middle, it is possible to reliably prevent ink leakage due to defective joining. Furthermore, since the base body of the pressure generating unit and the ceramics constituting the vibration generating unit can be fired at temperatures suitable for each, reliability can be improved.

[0025]

As described above, according to the present invention, since it can be supplied as a member separate from the flow path unit, it can be manufactured in an environment suitable for forming piezoelectric elements, electrodes, etc., and the yield can be improved. In addition, it is possible to configure a recording head that can be thinned by a simple operation of joining the flow path unit.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an ink jet recording head using a pressure generating unit of the present invention.

FIG. 2 is an exploded perspective view showing an embodiment of an ink jet recording head using the pressure generating unit of the present invention.

FIG. 3 is a diagram showing a relative positional relationship between pressure chambers.

FIG. 4 is a diagram showing a mounting position of a piezoelectric vibrator.

FIG. 5 is a perspective view showing a positional relationship between a piezoelectric vibrator and each electrode.

6 is a diagram showing a structure of a piezoelectric vibrator attached to a diaphragm in a cross section taken along line AA of FIG.

FIG. 7 is a perspective view showing an overview of a laminated inkjet recording head using the pressure generating unit of the present invention.

FIG. 8 is a perspective view showing a back surface structure of a laminated ink jet recording head using the pressure generating unit of the present invention.

9A and 9B are sectional views in the longitudinal direction and a width direction (line BB) showing a state when ink droplets are generated in the recording head.
2 is a cross-sectional view indicated by and.

10 (A) to 10 (V) are views showing a process of assembling a flow channel unit suitable for the pressure generating unit of the present invention and a process of fixing the pressure generating unit to the flow channel unit.

FIG. 11 is a diagram showing a step of adhering each plate constituting the flow path unit.

12 (a) and (b) are views showing an adhesive layer for adhering the flow path unit and the pressure generating unit, respectively.

[Explanation of symbols]

1 Pressure chamber forming member 2 Pressure chamber 4 diaphragm 5 Signal application electrode 6 Common electrode Extraction electrode 7 Piezoelectric vibrator 8 common electrode 10 Lid member 15 Pressure generation unit 20 Reservoir forming member 21 reservoir 24 Ink supply port member 26 Ink supply member 30 nozzle plate 31 nozzle opening 35 flow path unit

Claims (5)

(57) [Claims] 1. A pressure chamber forming member having a plurality of through holes forming a pressure chamber, an electrode extending from a position facing the pressure chamber to an end region on the surface, and a piezoelectric vibrator formed on the surface of the electrode. A plate member that seals one surface of the pressure chamber forming member, a through hole that forms a connection flow path between the reservoir and the pressure chamber, and a through hole that connects the pressure chamber and the nozzle opening, A pressure generating unit of a laminated inkjet recording head, which is configured by laminating a lid member that seals the other surface of the pressure chamber forming member. 2. The stack according to claim 1, wherein an electrode is formed that extends from a region where the piezoelectric vibrator is not formed to the end region and that is electrically connected to a common electrode that is formed on a surface of the piezoelectric vibrator. Type inkjet recording head pressure generation unit. Wherein the pressure chamber, the pressure generating unit of the multilayer ink jet recording head according to claim 1 which is formed to the long round rectangular shape ends of the major axis side is substantially circular. 4. The pressure generating unit of a laminated ink jet recording head according to claim 1, wherein the piezoelectric vibrator has a width smaller than a width of the pressure chamber. Wherein said pressure chamber is two rows so as to be positioned in a plurality straight line, the hole center-side for connecting the pressure chamber and the nozzle opening, also with said pressure chamber and the reservoir The pressure generating unit of the laminated ink jet recording head according to claim 1, wherein the through hole to be connected is formed so as to be located on the end side.