JP2002321375A - Flow path unit for multilayer inkjet recording head - Google Patents

Abstract

(57) [Problem] To provide a flow path unit constituting a thin ink jet recording head which is relatively easy to manufacture. SOLUTION: An ink supply member 26 made of a plate member having a through hole for supplying ink from an ink tank to a reservoir 21, a nozzle hole 31, a pressure chamber 2, and a through hole 27 connecting the pressure chamber 2 and the reservoir 21, respectively. The reservoir, the reservoir forming member 20 having a through hole connecting the nozzle opening and the pressure chamber, and the nozzle plate 30 fixed to the other surface of the reservoir forming member 20 and having the nozzle opening 31. It is configured to be integrally joined via an adhesive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head in which a piezoelectric vibrator is attached to a part of a pressure chamber communicating with a nozzle opening, and the piezoelectric vibrator compresses the pressure chamber to generate ink droplets. The present invention relates to a channel unit to be configured.

[0002]

2. Description of the Related Art An ink-jet recording head which stretches a piezoelectric vibrating plate in a partial area of a vibrating plate constituting a pressure chamber and changes the volume of the pressure chamber by displacement of the piezoelectric vibrating plate to generate ink droplets is known. In addition, since a large area of the pressure chamber can be displaced, an ink droplet can be stably generated. However, since the ink droplets fly in a direction perpendicular to the direction of displacement of the diaphragm, the size of the recording paper in the direction perpendicular to the paper surface increases, and there is a problem that the carriage and the like become large. In order to solve such a problem, the pressure-generating member including the diaphragm and the ink flow path forming member are formed in a laminated structure, and a nozzle opening is provided in parallel with the displacement direction of the diaphragm to reduce the thickness of the ink jet. A recording head has been proposed (Japanese Unexamined Patent Publication No. Sho 62
-111758). With such a laminated structure, not only the size can be reduced, but also a simple method of bonding a pressed or etched plate material can be applied, so that the manufacturing process can be simplified. However, since the adhesive of each plate is dependent on the adhesive, the flow of the adhesive into the small holes causes a decrease in the reliability due to the fluctuation of the flow path resistance, and the attachment of the piezoelectric vibrator to the diaphragm Is dependent on an adhesive, etching, or laser processing, which is problematic in that it takes time and effort.
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 laminated and fired to mount the piezoelectric vibrator. An ink jet recording head which does not require an operation has also been proposed (JP-A-63-149159).
However, as described above, the nozzle opening is provided in a direction perpendicular to the displacement direction of the diaphragm, and cannot be applied to make the recording head thinner.

[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 relatively easy-to-manufacture flow path unit constituting a thin ink jet recording head. To provide.

[0004]

SUMMARY OF THE INVENTION In order to solve such a problem, according to the present invention, a through hole for supplying ink from an ink tank to a reservoir, a nozzle opening and a pressure chamber, and the pressure chamber and the reservoir are formed. An ink supply member made of a plate material having a through hole to be connected to each other, a through hole connecting the nozzle opening and the pressure chamber, and a reservoir forming member having the reservoir; and the other surface of the reservoir forming member. A nozzle plate having the nozzle opening to be fixed is integrally joined to the nozzle plate via an adhesive layer.

[0005]

[Function] A thinner and smaller flow path unit can be supplied as a separate member from a pressure unit such as a piezoelectric element or an electrode which requires precise work, so that work efficiency can be improved, and the pressure unit can be easily joined. The recording head can be configured by work.

[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 and an exploded perspective view showing an embodiment of the present invention.
A pressure chamber forming member, a thickness suitable for forming a pressure chamber,
For example, as shown in an enlarged view in FIG. 4, a long circular rectangular pressure chamber 2, 2, 2... In which a long-axis end is rounded on a ceramic plate made of zirconia (ZrO 2) of 150 μm.
And one end of the reservoir 2 as shown in FIG.
1 and long holes 2 ', 2', 2 '#, the other end of which overlaps the nozzle opening 31, are formed at a constant pitch. Reference numeral 4 denotes a diaphragm fixed to one surface of the pressure chamber forming member 1, which is a material having good compatibility and a high elasticity when fired integrally with the pressure chamber forming member 1, and in this embodiment, a pressure chamber forming member. Similarly to the above, a zirconia thin plate having a thickness of 10 μm is formed, and the drive signal applying electrode 5 of the piezoelectric vibrator 7 corresponding to the pressure chamber 2 as shown in FIG.
An 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 in length to the longitudinal direction of the pressure chamber 2 and has a small width, such as PZT, as shown in FIG. It is made of a thin plate of a vibrating material, and is configured to vibrate in a mode that bends in the width direction with the longitudinal direction as an axis. As shown in FIGS. 5 and 6, the common electrodes 8 are formed on the surfaces of the piezoelectric vibrators 7, 7, 7 # and the extraction electrodes 6 by a film forming method such as sputtering. As a result, the respective piezoelectric vibrators 7 are connected to the drive signal applying electrode 5 on the vibration plate 4 side and to the common electrode 8 on the front surface side. 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 to slightly protrude W and W ′ from both ends in the width direction.

Reference numeral 10 denotes a lid member which forms the pressure chamber 2 in cooperation with the vibration plate 4, and is a material which is compatible with the pressure chamber forming member 1 when fired integrally, in this embodiment, a thin plate of zirconia having a thickness of 150 μm. And a through hole 11 for connecting a nozzle opening 31 and a pressure chamber 2 to be described later, and a reservoir 21 and a pressure chamber 2
Is formed by drilling a through hole 12 for connecting. These members 1, 4, and 10 are integrally fixed as a pressure generating unit 15.

Reference numeral 20 denotes a reservoir forming member which forms the flow path unit 35. The reservoir forming member 21 is formed on a corrosion-resistant plate material such as stainless steel of 150 μm suitable for forming the ink flow path. A through hole 21 ′,
Through hole 22 serving as a communication passage connecting pressure chamber 2 and nozzle opening 31
It is constructed by drilling. Through hole 2 serving as reservoir 21
1 ′ is connected to each pressure chamber 2, 2, 2 from the ink supply port member 24.
It is configured to extend in parallel with the end of ‥‥. That is, in this embodiment having two nozzle opening rows,
With the ink supply port member 24 as a tip, a branch is made into a “V” shape, and a linear flow path is formed from each branch to the pressure chambers 2, 2, 2.

Reference numeral 26 denotes an ink supply member fixed to one of the above-mentioned reservoir forming members 20, and a through hole 27 connecting the pressure chamber 2 and the nozzle opening 31;
And an ink supply port forming member 24 connected 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 and suitable for forming a nozzle opening having a diameter of 40 μm. Nozzle opening 31, 31 ‥
‥ is provided. These members 20, 26, 30
Each of them is integrally laminated by an adhesive, welding, or the like, and assembled as a flow path unit 35. Since these members 20, 26, and 30 are made of metal, even if they have a large through-hole 21 'for forming a reservoir inside, even if a pressure for obtaining a sufficient adhesive strength is applied, the members 20, 26, and 30 bite or deform. , And high accuracy and dimensional accuracy can be maintained to form a layer.

The pressure generating unit 15 and the flow path unit 35 are integrally fixed by applying an adhesive to the opposing surfaces thereof, that is, the contact surface between the lid member 10 and the ink supply member 26 to constitute a recording head. Is done. Thereby, the pressure chamber 2 is connected to the through hole 12 of the lid member 10 and the ink supply member 26.
Is connected to the reservoir 21 through the through hole 28 of the ink supply member 26, and to the nozzle opening 31 through the through hole 27 of the ink supply member 26 and the through hole 22 of the reservoir forming member 20. .

FIGS. 7 and 8 show the structure of the front side and the back side of the multi-layer ink jet recording head of the present invention, respectively.
Are arranged at a constant interval in two rows, and the pressure generating unit 1
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 about the longitudinal direction 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 here. The ink in the pressure chamber 2 is supplied to the through-hole 11 of the lid member 10.
From the through hole 27 of the ink supply member 26 and the flow path unit 35
Moves through the through hole 22 of the reservoir forming member 20 to the nozzle opening 31 of the nozzle plate 30, and comes out as an ink droplet from this.

The flow path connecting the pressure chamber 2 and the nozzle opening 31 includes through holes 11, 27, 2 formed in the lid member 10, the ink supply member 26, and the reservoir forming member 20.
2, and the diameter of the nozzle opening side is gradually reduced, so that the bubbles in the pressure chamber hardly enter the flow path. The ink in the pressure chamber 2 is supplied through the through holes 12, 2, and 2.
Although the fluid also flows into the reservoir 21 through 8, the diameter of the through hole 28 is small, so that there is no pressure loss to such an extent as to affect the flight of the ink droplet.

The application of the drive signal is released and the piezoelectric vibrator 7 is released.
Returns to the 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 supplied 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 opening 31, but the nozzle opening 31, 31,
The meniscus generated at 31 ° prevents the ink from retreating to the pressure chamber side, and effectively acts on ink suction from the reservoir 21.

Since the flow path unit 35 and the pressure generating unit 15 are connected via a thin layer of an adhesive made of a polymer material of about 30 μm, a difference in thermal expansion between the two units occurs due to a temperature change. However, the difference in thermal expansion is not buffered by the adhesive layer and does not cause distortion in the nozzle plate, so that a decrease in print quality is prevented by the adhesive layer.

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

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

Needless to say, even if the first sheet 40 serving as a pressure chamber forming member is provided with a through hole 41 serving as a pressure chamber, the width of the through hole 41 is extremely small. The pressure is appropriately concentrated on the portion of the through hole 41 without causing unnecessary deformation of the third and second sheets 45 and 42 which sometimes become the vibration plate and the cover member, thereby forming the vibration plate and the cover member. This contributes to sintering the sheets 45 and 42 to the first sheet 40, and helps to finish the volume of the pressure chamber according to design standards.

Each of the sheets 40, 42, and 45 functions as a pressure chamber forming member 50, a lid member 51, and a diaphragm 52 by firing. 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-out terminal by a thick film printing method and dried. Next, a thick film of a clay-like piezoelectric material is printed using a mask in which through holes are formed in accordance with the shape of the pressure chamber 53. At the time when the material for forming the vibrator is dried to a state suitable for firing, the whole is heated at a temperature suitable for firing the piezoelectric vibrator and the electrode, for example, about 1000 to 1200 ° C. Thus, a piezoelectric vibrator 54 can be formed in each pressure chamber 53 (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 technique such as sputtering so as to cover the common electrode lead-out terminal and the piezoelectric vibrator 54, the diaphragm, the pressure chamber forming member, and the lid member are configured as the same material as a block. Complete pressure generating unit.

On the other hand, an ink supply member 60 in which through holes 61 and 62 corresponding to the communication holes 27 and the flow path restriction holes 28 are formed by pressing a metal plate having a predetermined thickness,
A reservoir forming member 66 in which through holes 64 and 65 serving as the communication holes 1 and the communication holes 22 are formed by pressing, and a nozzle plate 69 in which through holes 68 serving as the nozzle openings 31 are formed by pressing are prepared, as shown in FIG. Thus, the through holes 70, 70,..., 7 between the members 60, 66, 69 allow for a margin of adhesion that does not block the through holes 61, 62, 64, 65, 68 of the members.
A channel unit is formed by thermocompression bonding with adhesive films 75 and 76 provided with perforations 1, 72, 72, 72 #, 73 (FIG. 10 III).

As shown in FIG. 12A, an adhesive is applied to the surface of one of the units, for example, the ink supply member 60 of the channel unit, on the joint surface between the pressure generating unit and the channel unit thus configured. The adhesive layer 80 is formed by coating or a heat-sealing film (FIG. 10 IV), and the lid member 51 of the pressure generating unit is inserted into the through holes 56 and 57.
When they are aligned and joined so that they are concentrically positioned (FIG. 10V), an adhesive layer 81 serving as a cushioning material for absorbing a difference in thermal expansion between different materials is provided between the flow path unit and the pressure generating unit. The completed recording head is completed. Since the adhesive layer 80 spreads horizontally when pressure is applied from the two members to be joined, a region 82 where the adhesive is not applied is provided on the outer periphery of the through hole, and the through hole of the lid member 51 and the ink supply member 60 is formed. It is prevented from flowing.

According to this embodiment, the pressure generating member is made of ceramics having a lower density than metal, so that the vibration transmitted from the adjacent piezoelectric vibrator has a large damping degree as much as possible. And crosstalk can be prevented. In addition, since a member that is constantly deformed by vibration can be integrally formed without intervening a dissimilar material in the middle, it is possible to reliably prevent ink leakage due to poor joining. Furthermore, since the base of the pressure generating unit and the ceramics constituting the vibration generating unit can be fired at a temperature suitable for each, the reliability can be improved.

[0025]

As described above, according to the present invention, a thin and compact flow path unit can be supplied as a member separate from a pressure unit such as a piezoelectric element or an electrode which requires a precise operation. Can be improved, and the recording head can be formed by a simple operation of joining the pressure units.

[Brief description of the drawings]

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

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

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

FIG. 4 is a view 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.

FIG. 6 is a diagram showing the structure of the piezoelectric vibrator attached to the diaphragm in a cross section taken along line AA of FIG. 5;

FIG. 7 is a perspective view showing an overview of an ink jet recording head using the flow channel unit of the present invention.

FIG. 8 is a perspective view showing a back surface structure of an ink jet recording head using the flow channel unit of the present invention.

FIGS. 9A and 9B show a state in which ink droplets are generated in the recording head in a cross section in a longitudinal direction and a width direction (line BB);
FIG.

FIGS. 10 (I) to (V) are views showing a method of manufacturing a flow channel unit of the present invention and a step of fixing a pressure generating unit, respectively.

FIG. 11 is a view showing a bonding step of each plate constituting the flow channel unit.

FIGS. 12 (a) and (b) are diagrams showing an adhesive layer for bonding a channel unit and a pressure generating unit, respectively.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 pressure chamber forming member 2 pressure chamber 4 diaphragm 5 signal applying electrode 6 common electrode extraction electrode 7 piezoelectric vibrator 8 common electrode 10 cover member 15 pressure generating unit 20 reservoir forming member 21 reservoir 24 ink supply port member 26 ink supply member 30 Nozzle plate 31 Nozzle opening 35 Channel unit

Claims (2)

[Claims] An ink supply member comprising a plate material having a through hole for supplying ink from an ink tank to a reservoir, a nozzle opening and a pressure chamber, and a through hole connecting the pressure chamber and the reservoir, respectively, and the nozzle A through hole for connecting an opening and the pressure chamber, and a reservoir forming member including the reservoir, and a nozzle plate including the nozzle opening fixed to the other surface of the reservoir forming member via an adhesive layer. A flow path unit of a laminated type ink jet recording head integrally formed. 2. The flow path of the multilayer ink jet recording head according to claim 1, wherein the adhesive layer is formed of a thermocompression-bondable adhesive film having through holes so as not to obstruct the flow of ink. unit.