JPH06198895A - Manufacture of ink-jet head - Google Patents

Abstract

PURPOSE:To provide a manufacture of an ink-jet head which can reduce drastically a production cost, has favorable energy efficiency and is capable of miniaturization of the head. CONSTITUTION:After printing of piezoelectric paste containing a piezoelectric material is printed on the surface of an oscillation plate 5 formed of a material having heat resistance enduring a firing temperature of a piezoelectric body layer 9 by corresponding to a position of a pressure chamber to impart discharge pressure to ink, heating and firing are performed and the piezoelectric layer 9 is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an ink jet head for recording by ejecting ink droplets.

The ink jet recording system has features such as a simple structure, easy colorization, and no noise, and is expected as the mainstream of future recording systems.

[0003]

2. Description of the Related Art In order to eject ink droplets from an ink jet head, a vibrating plate provided facing the pressure chamber is vibrated to apply an ejection pressure to the ink in the pressure chamber.

Generally, a piezoelectric element vibrates the diaphragm, and the piezoelectric element is provided in close contact with the surface of the diaphragm corresponding to the position of the pressure chamber. In the past, such a piezoelectric element was individually formed separately from the diaphragm to have a size corresponding to the size of the pressure chamber, and then bonded to the surface of the diaphragm one by one.

[0005]

However, since it is necessary to attach the same number of piezoelectric elements to the ink jet head as the number of ink discharge nozzles, it is very time-consuming to attach each piezoelectric element to the diaphragm. , Increases the manufacturing cost of the head.

Further, in order to miniaturize the head, it is necessary to arrange the pressure chambers at a high density. Therefore, it is necessary to make the piezoelectric element small in accordance with it, and accordingly it is necessary to reduce the thickness. .

However, if the piezoelectric element is made too small and thin (for example, the size is 1 × 1 mm or less and the thickness is 0.1 mm or less), it becomes difficult to handle at the time of assembling. It was not possible to make it too small, which was a bottleneck for head miniaturization.

Further, since the layer of the adhesive between the piezoelectric element and the diaphragm absorbs the motion to be transmitted from the piezoelectric element to the diaphragm, there is a functional problem that the energy efficiency is poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method of manufacturing an ink jet head which can significantly reduce the manufacturing cost of the head, has high energy efficiency, and can be downsized.

[0010]

In order to achieve the above object, a method for manufacturing an ink jet head according to the present invention includes a piezoelectric layer 9 as shown in FIG. 1 for explaining an embodiment.
A piezoelectric paste containing a piezoelectric material is printed on the surface of the vibrating plate 5 formed of a material having heat resistance that can withstand the firing temperature, at a position corresponding to the position of the pressure chamber 2 for applying the ejection pressure to the ink. And then heating and firing to form the piezoelectric layer 9.

The vibrating plate 5 is for forming a plurality of ink jet heads 4 on one sheet, and a piezoelectric layer 9 for forming the plurality of ink jet heads 4 is simultaneously printed on the vibrating plate 5. You may make it heat and bake.

After forming the electrode layer 8 on the surface of the vibration plate 5 in advance, the piezoelectric layer 9 and the electrode layer 10 are printed and fired on the electrode layer 8 in correspondence with the position of the pressure chamber 2. You may.

[0013]

The piezoelectric layer 9 is directly baked on the surface of the vibration plate 5 by printing the piezoelectric paste on the surface of the vibration plate 5 corresponding to the position of the pressure chamber 2 and then heating the paste.

In this case, a plurality of ink jet heads 4
The piezoelectric layer 9 for forming the plurality of ink jet heads 4 can be simultaneously printed on one vibration plate 5 for forming, and heated and baked.

Before printing the piezoelectric layer 9, the vibrating plate 5
If the electrode layer 8 is previously formed on the surface of, the so-called lower electrode can be obtained.

[0016]

Embodiments will be described with reference to the drawings. 1 to 11 show a first embodiment of the present invention. First, as shown in FIG. 2, for example, a silicon single crystal wafer 1 having a thickness of 0.5 mm is etched to form a pressure chamber 2 and a pressure chamber 2. The ink flow path 3 and the ink flow path 3 are each formed to a predetermined depth.

Although FIG. 2 shows one pressure chamber 2, as shown in FIG. 3, one silicon wafer 1 is used.
Is a size for collectively forming a large number of inkjet heads 4, and as shown in FIG. 4 showing a part A of one inkjet head 4, a large number (for example, 64) of pressures are applied to each inkjet head 4. Room 2 ... is arranged.

Next, as shown in FIG. 5, the silicon single crystal wafer 1 is ground to a thickness of 0.1 mm, for example, from the surface opposite to the side where the pressure chamber 2 is formed. As a result, the back side portion of the pressure chamber 2 has a predetermined thickness (for example, 0.
02 to 0.025 mm).

Next, as shown in FIG. 6, a nozzle plate 7 made of a silicon single crystal wafer having nozzle holes 6 formed by etching is formed on the silicon single crystal wafer 1 so as to cover the surface of the pressure chamber 2. To join.

This joining can be carried out by so-called direct joining, in which the joining surfaces are brought into close contact with each other and heated in vacuum at, for example, 1100 ° C. for 30 minutes to integrate the joining surfaces.

The positional relationship between the nozzle hole 6 and the pressure chamber 2 is as shown in FIG. 7, and the silicon single crystal wafer 1 and the nozzle plate 7 are arranged so that the nozzle hole 6 is located near the end of each pressure chamber 2. And can be combined.

Next, as shown in FIG. 8, the surface of the silicon single crystal wafer 1 opposite to the pressure chamber 2, that is, the vibrating plate 5.
On the entire surface of, for example, a conductive paste having a viscosity adjusted to 2000 cP by mixing, for example, a powder of silver and palladium, a binder for binding them, and an organic solvent, is printed to a thickness of 5 μm by a screen printing method, After drying, the lower electrode layer 8 is baked by heating at a high temperature of 1000 ° C. for 2 hours in an electric furnace.

Since the silicon single crystal wafer 1 is not melted up to a high temperature of about 1200 ° C. and no distortion occurs, it can sufficiently withstand the heat treatment at the time of firing as described above.

Next, on the surface of the lower electrode layer 8, for example, piezoelectric fine powder (PZT) made of lead oxide, zirconium oxide and titanium oxide, a binder for binding the powders and an organic solvent are mixed. And viscosity is 3000 cP
The piezoelectric paste adjusted in step 1 is printed with a thickness of 30 μm by screen printing.

When the piezoelectric layer 9 is formed by screen printing, the thickness is preferably in the range of 5 to 100 μm, and the electrode layers 8 and 10 may be formed in the thickness of 1 to 10 μm. it can. The temperature for firing the electrode layers 8 and 10 and the piezoelectric layer 9 varies depending on the material used, but is 400
A range of ~ 1500C is used.

As a material for the piezoelectric paste, a material such as barium titanate-based ceramic, PMN-PT to which a compound having a perovskite structure is added, or PNN-PTPZ can be used.

In the screen printing, as schematically shown in FIG. 9, a screen 21 on which a print pattern is formed is arranged on the surface of the silicon single crystal wafer 1, and a conductive paste or a piezoelectric paste 22 is applied on the screen 21. It is performed by pressing the squeegee 23 and moving it.

At this time, the piezoelectric paste 22 is printed by
The position and size of the pressure chamber 2 are matched. When the printed piezoelectric paste 22 is dried, it is heated in an electric furnace at a high temperature of, for example, 1000 ° C. for 2 hours to burn off an organic solvent or the like from the piezoelectric paste 22.

As a result, as shown in FIGS. 10 and 11, the piezoelectric layer 9 is fired on the surface of the vibrating plate 5 so as to match the position and size of each pressure chamber 2. When the piezoelectric layer 9 is fired in this manner, finally, as shown in FIG. 12, an upper electrode layer 10 having a thickness of 3 is formed on the surface of the piezoelectric layer 9.
Print and fire at μm. The material and firing conditions of the upper electrode layer 10 may be the same as those of the lower electrode layer 8.

As described above, in the present invention, the diaphragm 5
Since the electrode layer 8 and the piezoelectric layer 9 are directly formed on the surface of, the manufacturability is excellent, and the desired thickness, size, and shape can be formed with high reliability.

When the piezoelectric layer 9 and the upper and lower electrode layers 8 and 10 are formed on the surface of the vibrating plate 5 in this way, the whole structure is shown in FIG.
The inkjet heads 4 shown in FIG.

In the ink jet head thus formed, the ink is supplied from the ink flow path 3 to the pressure chamber 2.
The piezoelectric layer 9 is deformed by filling the inside and applying a voltage between the upper and lower electrodes 8 and 10, whereby the vibrating plate 5 vibrates and an ejection pressure is applied to the ink in the pressure chamber 2,
The ink in the pressure chamber 2 is discharged as an ink droplet from the nozzle hole 6 to perform recording.

In the present invention, the thickness of the piezoelectric layer 9 can be freely formed within the range of 2 to 200 μm by controlling the thickness of the printing plate. Therefore, the thickness of the piezoelectric layer 9 is set to the most preferable thickness with respect to the thickness of the vibration plate 5, and the particles can be ejected from the nozzle with high particle formation efficiency and low drive voltage.

Further, since the vibrating plate 5 and the electrode layer 8 and the electrode layer 8 and the piezoelectric layer 9 are directly joined by printing and firing, there is no adhesive layer as in the prior art, and the efficiency of particle formation is further enhanced. You can

12 and 13 show a second embodiment of the present invention, in which photosensitive glass is used as the nozzle plate 7, and the lower electrode layer 8 is formed by depositing platinum by sputtering. It is a thing.

In this case, since the photosensitive glass cannot withstand the firing temperature of the piezoelectric layer 9, as shown in FIG. 12, the piezoelectric layer is not attached to the silicon single crystal wafer 1 before the nozzle plate 7 is attached. 9 and the upper electrode layer 10 are printed and fired, after which the nozzle plate 7 as shown in FIG.
Are bonded to the silicon single crystal wafer 1.

FIGS. 14 to 16 show a third embodiment of the present invention. First, one stainless steel substrate 3 is used.
1, the pressure chamber 2 and the ink supply path 3 are formed by etching. The size of the pressure chamber 2 is, for example, 1 × 2 mm,
The diameter of the outlet of the nozzle hole 6 is 50 μm.

The vibrating plate 5 is made of an austenitic stainless steel plate (SUS304) having a thickness of 50 μm, and the substrate 31 and the vibrating plate 5 are joined by diffusion bonding.

A printing plate having an opening mesh of 1 × 2 mm is placed on the vibrating plate 5, an electrode material containing silver as a main component is mixed with an organic resin binder and an organic solvent, and the viscosity is 2000 c.
The paste adjusted to P is squeegeeed to a thickness of 5 μm.
To form the lower electrode 8 as shown in FIG.

Then, a paste containing a piezoelectric material is printed thereon with a thickness of 50 μm using a printing plate of the same shape to form a piezoelectric layer 9 as shown in FIG. The piezoelectric material used was a powder of PZT mixed with an organic resin binder to have a viscosity adjusted to 3000 cP.

Further, the same material as the lower electrode layer 8 is printed on the piezoelectric layer 9 to a thickness of 3 μm to form the upper electrode 10 as shown in FIG. Then, the entire inkjet head configured as described above is heated in a heating furnace at 100 ° C. for 10 minutes, and further heated in a heating furnace at 1000 ° C. for 1 minute.
Heat for hours.

By injecting the ink liquid into the ink jet head manufactured as described above and applying a voltage of 50 V to the electrodes 8 and 10, the ink droplets are stably ejected from the nozzle holes 6 at a speed of 7 m / s. I was able to.

For comparison, a conventional manufacturing method of 1 × 2 mm,
As a result of investigating the characteristics of a head manufactured by adhering a piezoelectric element having a thickness of 100 μm with an epoxy resin adhesive, a voltage of 120 V was required to obtain a similar particle velocity.

It is to be noted that, by using a heat-resistant glass having a thickness of 100 μm for the vibrating plate 5, both electrodes 8 and 10 have a thickness of 2 μm and the piezoelectric layer 9 has a thickness of 20 μm in the same manner as the third embodiment.
In the ink jet head which was printed by the screen printing method at a thickness of 100 ° C., heated at 100 ° C. for 10 minutes and then baked at 900 ° C. for 1 hour, a particle velocity of 7 m / s was obtained at an applied voltage of 60 V.

FIG. 17 shows a fourth embodiment of the present invention, in which the same head constituent material, electrode material and piezoelectric material as those of the third embodiment are used by using the dispenser 40 to form the diaphragm 5.
On top of which an electrode layer 8 (thickness of 3 μm) and a piezoelectric layer 9 (25 μm
m thickness) and the electrode layer 10 (3 μm thickness) in order of radius 0.5
A head was manufactured as a prototype by forming it into a disk shape of mm and then heating and firing.

The viscosity of the printing paste at this time is 500
It was suitable to be about cP. As a result of investigating the characteristics of the manufactured inkjet head, a particle velocity of 7 m / s was obtained at 40V.

18 and 19 show a fifth embodiment of the present invention, in which a nozzle plate 7 having a plurality of nozzle holes 6 and
In the multi-nozzle head configured by the vibration plate 5 and the ink flow path plate 41 in which the pressure chambers 2 corresponding to the plurality of nozzle holes 6 are formed, the piezoelectric layer 9 is formed on the part of the vibration plate 5 corresponding to each pressure chamber 2. Is formed by printing.

In this embodiment, the number of nozzle holes 6 is 64, and 64 pressure chambers 2 corresponding to this are also arranged. The size of one pressure chamber 2 is 0.5 x 1.0
mm.

In manufacturing this, first, a screen printing plate having an opening mesh corresponding to the entire 64 pressure chambers 2 is used on the vibrating plate 5, and an electrode material containing silver as a main component is used as an organic material. Mix with resin binder and organic medium to increase viscosity to 2
The paste adjusted to 000 cP is printed with a squeegee to a thickness of 5 μm to form the lower electrode 8.

Next, a piezoelectric plate 9 having a thickness of 40 μm is formed by using a printing plate having a plurality of opening meshes corresponding to the pressure chambers 2.
Print with m. Further, an electrode material similar to that of the lower electrode 8 is printed on each piezoelectric layer 9 in a thickness of 3 μm to form an upper electrode (not shown).

The head manufactured in this way is
The inkjet head is completed by heating at 0 ° C for 10 minutes and then baking at 1000 ° C for 2 hours.
Then, as a result of injecting ink into this head and applying a voltage pulse to each electrode, ink particles were ejected from each nozzle hole 6 at an average speed of 7 m / s at a drive voltage of 40V. The variation in the particle velocity of each nozzle hole 6 was ± 10% or less.

For comparison, 0.5 was obtained by the conventional manufacturing method.
A head was manufactured by adhering piezoelectric elements each having a thickness of 1.0 mm and a thickness of 100 μm one by one with an epoxy adhesive, and the characteristics of the head were investigated. A particle velocity of 7 m / s was obtained. The variation in the speed of each nozzle was ± 30% or more.

FIG. 20 shows a sixth embodiment of the present invention. One ink jet head material 51 is one stainless steel substrate on which a flow path is formed by etching.

The size of the outlet of the nozzle hole 6 is 50 μm in diameter.
The size of the pressure chamber 2 is 0.5 × 1.0 mm.
The vibration plate 5 is made of a stainless steel plate (SUS304),
The thickness was 50 μm. The vibration plate 5 and the flow path substrate are joined by
Diffusion bonding was used.

The ink jet head material 51 thus formed is placed on the head fixing jig 50 of 4 × 5 rows with the diaphragm 5 facing upward as shown in FIG. Although not shown in the drawing, on the diaphragm 5 of these heads, openings for one head in which 64 opening meshes of 0.5 × 1.0 mm are arrayed are further arranged in total of 4 rows and 5 columns, for a total of 20 rows. Printing plates 21 in which heads are arranged are stacked, an electrode material containing silver as a main component is mixed with an organic resin binder and an organic solvent, and a paste having a viscosity adjusted to 2000 cP is printed with a squeegee 23 to a thickness of 5 μm. To form the lower electrode layer 8.

Further, the piezoelectric layer 22 was formed by printing the piezoelectric paste 22 with a thickness of 30 μm using the printing plate 21 having the same shape. The piezoelectric paste 22 used was prepared by mixing PZT powder and an organic resin binder to adjust the viscosity to 3000 cP.

Further, the same material as the lower electrode layer 8 was printed on the piezoelectric layer 9 by 3 μm to form an upper electrode 10.
Then, the entire head fixing jig 50 was heated in a heating furnace at 100 ° C. for 10 minutes and further baked in a heating furnace at 1000 ° C. for 1 hour.

The thus-manufactured ink jet heads 4 are taken out of the head fixing jig 50, ink is injected into these heads 4, and voltage pulses are applied to the respective electrodes. As a result, each nozzle hole is driven at a driving voltage of 40V. Ink particles were ejected at a speed of 6 to 7 m / s on average.

The variation in particle velocity of each nozzle hole 6 is ± 1.
0% or less, and the average flow velocity of 20 heads is 7
The variation was within m / s ± 5%. For comparison, 0.5 × 1.0 mm, thickness 100 μm by conventional manufacturing method
Attach the piezoelectric elements of each one with epoxy adhesive one by one.
As a result of making heads and investigating the characteristics of the heads, a particle velocity of 7 m / s was obtained as an average of all nozzles at a high driving voltage of 150 V, but the variation in the velocity of each nozzle was ± 30% or more. The average speed variation of the 20 heads was ± 25% or more.

FIG. 21 shows a seventh embodiment of the present invention, in which 64 head constituent materials, electrode materials and piezoelectric materials similar to those in the sixth embodiment shown in FIG. 20 are arranged per head. Further, a lower electrode layer (thickness of 3 μm) is formed on the vibrating plate 5 by using a dispenser 60 having a plurality of nozzles corresponding to a pattern in which the heads are arranged in 4 × 5 rows.
Piezoelectric layers (thickness of 25 μm) and upper electrode layers (thickness of 3 μm) were formed in this order into a disk shape with a radius of 0.5 mm, and then heated and fired to manufacture a plurality of heads at the same time.

The viscosity of the printing paste at this time is 500
About cP was suitable. As a result of examining the characteristics of 20 prototype heads, the variation in particle velocity was ± 20% or less.

It should be noted that the head constituent material of the present invention can be applied not only to the materials described here, but also to ceramics such as alumina, various metals and photosensitive glass, and various crystalline materials. Nor. Further, as the electrode material and the material of the piezoelectric layer, various materials can be used as well as the head constituent material.

The present invention is not limited to the above-mentioned embodiments, and for printing, for example, any printing method other than screen printing such as letterpress or intaglio may be used.

[0064]

According to the method of manufacturing an ink jet head of the present invention, since the piezoelectric layer is formed on the surface of the vibration plate by printing and firing, the number of assembling steps can be reduced and a large cost reduction can be achieved. Moreover, since the piezoelectric layer can be formed to a thin and high density which is as small as the limit of the printing technology, the inkjet head can be remarkably downsized.

Further, since the diaphragm and the piezoelectric layer are formed in direct contact with each other without an adhesive layer, the deformation of the piezoelectric layer is efficiently transmitted to the diaphragm, and the energy loss is very small. It is efficient.

[Brief description of drawings]

FIG. 1 is a front partial cross-sectional view showing a manufacturing process of a first embodiment.

FIG. 2 is a front partial cross-sectional view showing the manufacturing process of the first embodiment.

FIG. 3 is an overall plan view showing a manufacturing process of the first embodiment.

FIG. 4 is a plan sectional view showing a manufacturing process of the first embodiment.

FIG. 5 is a front partial cross-sectional view showing the manufacturing process of the first embodiment.

FIG. 6 is a partial front sectional view showing the manufacturing process of the first embodiment.

FIG. 7 is a plan view showing a manufacturing process of the first embodiment.

FIG. 8 is a front partial cross-sectional view showing the manufacturing process of the first embodiment.

FIG. 9 is a schematic side view showing the manufacturing process of the first embodiment.

FIG. 10 is a plan view showing a manufacturing process of the first embodiment.

FIG. 11 is a partial front sectional view showing the manufacturing process of the first embodiment.

FIG. 12 is a front partial cross-sectional view showing the manufacturing process of the second embodiment.

FIG. 13 is a front partial cross-sectional view showing the manufacturing process of the second embodiment.

FIG. 14 is a front cross-sectional view showing the manufacturing process of the third embodiment.

FIG. 15 is a front cross-sectional view showing the manufacturing process of the third embodiment.

FIG. 16 is a front cross-sectional view showing the manufacturing process of the third embodiment.

FIG. 17 is a partial vertical cross-sectional view showing the manufacturing process of the fourth embodiment.

FIG. 18 is a plan view showing a fifth embodiment.

FIG. 19 is a front sectional view showing a fifth embodiment.

FIG. 20 is a schematic front sectional view showing a manufacturing process of the sixth embodiment.

FIG. 21 is a schematic front view showing the manufacturing process of the seventh embodiment.

[Explanation of symbols]

 2 Pressure chamber 5 Vibration plate 9 Piezoelectric layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mineharu Tsukada 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor, Katsuharu Hida 1015, Kamedotachu, Nakahara-ku, Kawasaki, Kanagawa Prefecture, Fujitsu Limited

Claims (3)

[Claims] 1. A position of a pressure chamber (2) for applying an ejection pressure to ink on a surface of a vibrating plate (5) formed of a material having heat resistance to withstand a temperature for firing a piezoelectric layer (9). Corresponding to step 1, a method for manufacturing an ink jet head is characterized in that a piezoelectric paste containing a piezoelectric material is printed and then heated and fired to form the piezoelectric layer (9). 2. The vibrating plate (5) is for forming a plurality of inkjet heads (4) on one sheet, and a piezoelectric layer (9) for forming the plurality of inkjet heads (4) is provided. The method according to claim 1, wherein the vibration plate (5) is printed at the same time and heated and baked. 3. An electrode layer (8) is previously formed on the surface of the vibrating plate (5), and the piezoelectric layer corresponding to the position of the pressure chamber (2) is provided on the electrode layer (8). The method for producing an inkjet head according to claim 1, wherein (9) and the electrode layer (10) are printed and baked.