JP2001088303A - Ink jet print head and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet print head capable of improving the yield and simplifying the manufacturing process. SOLUTION: A print head is so constituted that ink supplying passage forming members 902, 903, 107 wherein an ink supplying passage for receiving supply of ink from the outside and a nozzle for ejecting an ink drop are formed and ink cavity forming members 101, 901 wherein an ink cavity 106 pressurized by an elastic diaphragm 103 which is elastically displaced are superposed with each other. A paste type piezoelectric material is screen-printed or a green sheet piezoelectric body is transferred on a surface of the elastic diaphragm 103 where the each piezoelectric element 102 is opposed to each ink cavity 106 corresponding to the ink cavity 106, and then they are baked to be fixed with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a print head used for an ink jet printer.

[0002]

2. Description of the Related Art An ink jet print head is shown in FIG.
As shown in FIG. 7, a plurality of nozzle openings are formed on the wall surface of a container constituting an ink tank, and a piezoelectric element 430 is arranged so as to correspond to each of the nozzle openings so that the expansion and contraction directions are matched. The print head applies a drive signal to the piezoelectric element to expand and contract the piezoelectric element, and discharges ink droplets from the nozzle openings 421 by the dynamic pressure of ink generated at this time to form dots on printing paper. This print head forms a plurality of ink reservoirs, so-called ink cavities, between a glass or plastic substrate and an elastic diaphragm made of a thin plate of glass or plastic,
A piezoelectric plate having electrodes on both sides cut to about the area of the ink cavity is bonded to an elastic vibration plate on the ink cavity.

[0003]

However, due to the formation of nozzle openings, ink cavities, and ink reservoirs on the same substrate, if the area of the print head becomes large and one component fails, Due to missing dots, the print head cannot be used practically, and the yield tends to decrease particularly when a large number of nozzles are provided.
Not only is it difficult to reduce the cost, but also it is necessary to attach a large number of piezoelectric elements, and there is a problem that the manufacturing process is complicated. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an ink jet print head having a small number of nozzles and capable of reducing the manufacturing cost. Another object of the present invention is to propose a method for manufacturing the print head.

[0004]

In order to solve the above-mentioned problems, a print head according to the present invention comprises an ink supply path for receiving an ink supply from outside and an ink supply path formed with nozzles for ejecting ink droplets. A member, an ink cavity forming member in which an ink cavity pressurized through an elastically deformable elastic vibration plate is formed, and a surface of the elastic vibration plate opposed to each of the ink cavities, corresponding to the ink cavity. After screen-printing a paste-like piezoelectric material, or after transferring a green sheet-like piezoelectric body, the piezoelectric body fixed by baking, the ink cavity forming member is located inside the ink flow path forming member. One end of the ink supply path is extended to a region not overlapping with the ink cavity forming member, and One end is positioned such that the vertical relationship between the ink supply path and the ink cavity is in communication with said ink supply path and the nozzle through the communication passage.

[0005]

Since the head is formed by combining the ink supply path forming member and the ink cavity forming member formed separately, the manufacturing yield is improved, and the surface of the elastic vibration plate facing each ink cavity is provided on the surface. After screen-printing a paste-like piezoelectric material or transferring a green sheet-like piezoelectric material corresponding to the ink cavities, the piezoelectric elements are fixed by firing, so the individual piezoelectric elements are attached. Becomes unnecessary.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 is a top view showing one embodiment of the ink jet print head of the present invention, and FIGS. 2A and 2B are views each showing a sectional structure. The piezoelectric body 102 is formed in a thin plate shape, and the elastic vibrating plate 103 is formed so as to correspond to the ink cavity 106.
Is fixed to the surface of the individual electrode 105 formed on the surface of the substrate. An individual electrode 105 is formed below the piezoelectric body 102, that is, on the elastic vibration plate 103, and a common electrode 104 is formed on the surface of the piezoelectric body 102.

The individual electrodes 105 are independently formed for each piezoelectric body so as to extend in the longitudinal direction of the piezoelectric body 102 to a region where the piezoelectric body 102 is not formed, and a drive signal is applied from the outside. The lead portion 105a of the individual electrode 105 is divided on the way, and the resistor 111 is connected between the lead portion 105a and the other lead portion 105b. Then, the extraction portion 105 of each individual electrode 105
a is formed so as to be larger than the arrangement pitch of the individual electrodes 105.

The piezoelectric body 102, the elastic diaphragm 103,
The common electrode 104, the individual electrode 105, and the resistor 111 constitute a pressure generating member 101.

An ink cavity 106 is provided on the lower surface of the pressure generating member 101, and an ink supply amount control nozzle 1 is provided below the ink cavity 106.
09 is located below the ink supply path 108 and the nozzle 110 is located further below the ink supply path 108. Ink cavity 1
06, ink supply amount control nozzle 109, ink supply path 1
08 is a different plate-shaped member 901, 902, 9
03 and the nozzle 110 is the nozzle plate 1
07. Member 901 and elastic diaphragm 103
The ink cavity forming member is laminated with
2, 903 and the nozzle plate 107 are laminated to form an ink supply path forming member.

In this embodiment, the ink cavity 10
6. Both the piezoelectric bodies 102 are arranged in a plurality of rows in two rows, nozzles 110 are arranged on opposite sides of each row, and ink supply amount control nozzles 109 are located on the separated side. The members 102 and 903 exist between the nozzle 110 and the ink cavity 106, and these members are smaller than the width of the ink cavity and smaller than the diameter of the nozzle 110 as shown in FIGS. The communication holes 114 are formed by forming large through holes 112 and 113.

The ink supply path 108 is formed in parallel with the ink cavities 106 of each row so as to partially overlap the ink cavities 106, communicates with the ink cavities 106 via the above-described ink supply amount control nozzles 109, and has an end area. And are integrally formed in a substantially "U" shape.

3 and 4 showing a manufacturing method which will be described later.
As is clear from FIG. 5, the individual electrode 105 formed below the piezoelectric body 102 is formed such that its width W1 is smaller than the width w3 of the ink cavity 106, and the piezoelectric body 102 has its width The width w2 is smaller than the width w3 of the ink cavity 106 and wider than the width W1 of the individual electrode 105. Also, the resistor 111
Are connected to the extraction portions 105a and 105b of the individual electrode 105 in a region where the elastic vibration plate 103 and the members 901 to 903 all overlap.

The ink is stored in the ink cavity 106 from the ink supply path 108 through the ink amount control nozzle 109, and is expanded and contracted by the driving signal transmitted from the individual electrode 105 forming the resistor 111. By repetition, the ink is pushed out from the nozzle 110, and after the ink droplet is ejected, the ink cavity 10 is supplied from the ink supply path 108 via the ink supply amount control nozzle 109.
6 is supplied with ink.

Next, a method of manufacturing the above-described print head will be described. First, the pressure generating member 101 is manufactured. Here, since the firing conditions (temperature, atmosphere, etc.) for the piezoelectric material differ depending on the resistor material to be selected, the piezoelectric body 102 and the resistor 111 may or may not be fired simultaneously.

[0015] When simultaneous firing is possible Alumina (A
A green sheet is formed using a material such as l2O3), zirconia (ZrO2), PZT, etc., dried and fired to obtain an elastic vibration plate 103. Here, the material forming the elastic vibration plate 103 is a material having a thermal expansion coefficient close to that of the piezoelectric body 102 in order to prevent distortion of the pressure generating member 101 due to a difference in thermal expansion coefficient during simultaneous firing with the piezoelectric body 102. It is desirable to choose.

Next, as shown in FIG. 3, on the surface of the elastic vibration plate 103, an individual electrode 105, a lead portion 105a, and a dividing portion 401 for forming the resistor 11 are opened to form a lead portion 105b.
Is formed by a screen printing method such as Ag-Pd or the like,
dry. Next, as shown in FIG. 4, on the surface of the individual electrode 105, a so-called piezoelectric precursor, which becomes the piezoelectric body 102 after firing of lead zirconate titanate (PZT) or the like, is formed corresponding to the position of the ink cavity 106. Piezoelectric body 10
As a method of forming 2, a method of selectively printing and forming a paste-like piezoelectric material by a screen printing method corresponding to the ink cavity 106 (hereinafter, referred to as a printing method).
And a method in which a green sheet-shaped piezoelectric material is formed into a desired shape by a pressing method or the like and transferred to the elastic vibration plate 103 (hereinafter, referred to as a transfer method).

In the printing method, PbO, TiO2, ZrO2, and additives are mixed and mixed, and then calcined at 800 to 1000 ° C., pulverized, and a binder is added to produce a PZT paste. By using a screen mask of about 400 to 1000 mesh patterned into a desired shape corresponding to the ink cavity 106, the individual electrodes 105, 105a,
PZT is formed on the surface of the elastic diaphragm 103 on which the 105b is formed.
Print and dry the paste.

On the other hand, the transfer method uses PbO, TiO2, Zr
After mixing and mixing O2 and additives, the mixture is calcined at 800 to 1000 DEG C. and pulverized to form a PZT paste by adding a binder, and the PZT sheet (green) is controlled in thickness by a doctor blade method, an extrusion method, or the like. Sheet). Next, as shown in FIG. 7, a green sheet 303 having a high releasability spread on a platen 301 by a pressing method or the like.
Is punched into a desired shape corresponding to the ink cavity 106 to form the piezoelectric material 302. Further, as shown in FIG. 8, the piezoelectric material 302 of the sheet 303 is transferred to the surface of the individual electrode of the elastic vibration plate 103 by being aligned with the elastic vibration plate 103 on which the individual electrode 105 is formed as shown in FIG. Then dry.

Next, as shown in FIG. 5, a resistor 111 such as ruthenium oxide (RuO 2) is placed in a region 401 between the lead portions 105 a and 105 b of the individual electrode 105.
20 so that 5a and 105b partially overlap
Screen printing with 0-400 mesh, then 12
Dry at 0-130 ° C.

As described above, the piezoelectric body 102, the electrode 105, and the extraction portions 105a and 105 are formed on the surface of the elastic vibration plate 103.
b, 1000-1200 formed resistor 111
Fire in air at ℃. Thereafter, as shown in FIG. 6, a common electrode 104 is formed on the surface of the piezoelectric body 102 by a printing method, a sputtering method, or the like. Thereafter, a resistance value inspection is performed, and resistance value trimming is performed by a laser trimmer as necessary so that each resistance value falls within an allowable variation level.

[0021] When Simultaneous Firing is not Possible: In the above-described manufacturing method, ruthenium oxide (RuO2)
Skipping the step of forming the resistor 111 such as 1000
After firing in the air at 1200 ° C., the resistor 111 such as carbon is connected to the lead portions 105 a,
5b, a part of each of the extraction portions 105a,
5b, screen-printed, and then dried to a temperature suitable for a carbon-based resistor material.
Bake at 0-200 ° C. Thereafter, as shown in FIG. 6, the common electrode 104 is formed, the resistance value is inspected, and the resistance value is trimmed by a laser trimmer as necessary so that each resistance value falls within the allowable variation level.

The pressure generating member 1 constructed as described above
01 is a member 90 having the ink cavity 106 formed therein.
1. The member 90 on which the ink supply amount control nozzle 109 is formed
2. The member 903 having the ink supply passage 108 and the nozzle plate 107 are laminated and adhered to complete the head.

The members 901, 902, 903 and the nozzle plate 107 are formed by printing on a metal plate such as SUS or Ni by injection molding of a polymer or by forming a resist in a desired shape by a photolithography process and leaving the resist. Etching method to remove unexposed parts by etching Print resist on substrate, form resist in desired shape by photolithography process, and apply N2 by electroless plating or electrolytic plating
An electroforming method for growing i and the like. There is a pressing method.

The pressure generating member 101, the ink cavity forming member 901, the ink supply amount control nozzle forming member 90
2. Ink supply path forming member 903, nozzle plate 10
As a method for bonding 7, a method using an adhesive such as epoxy or polyimide is applied to the ink cavity 106 and the nozzle plate 107.
When a metal such as i is selected, a metal such as Ni is metallized on the surface of the pressure generating member 101 to which the nozzle plate or the like is adhered by a sputtering method or a plating method.
06, a method in which the nozzle plates 107 are stacked, pressurized, and left in a high-temperature atmosphere to bond them by thermal diffusion.

Here, in the adhesive method, the nozzle is liable to be clogged by the adhesive due to the flow of the adhesive at the time of applying and curing the adhesive.
It is desirable that the thickness be controlled to μm or less.

The print head manufactured in this manner includes: a piezoelectric body 102 material: PZT; a piezoelectric body thickness: 30 μm; an elastic vibrating plate 103 material: ZrO2;・ 10 μm ・ Resistor 111 material ・ ・ ・ RuO2 manufacturing method ・ Piezoelectric 102 screen printing method ・ Common electrode 104 sputtering method ・ Individual electrode 105 screen printing method ・ Resistor 111 screen printing method ・ Ink cavity member 901 etching method ・ Nozzle plate 107 Etching method Ink cavity member 901, ink supply amount control nozzle forming member 902, ink supply path forming member 90
3. The nozzle plate 107 is joined to each other by a thermal diffusion method, and the pressure generating member 101 and the ink cavity member 901 are joined by an epoxy adhesive.

FIGS. 10 and 11 show another embodiment of the present invention, in which the cross section in the arrangement direction of the piezoelectric bodies 102 and the longitudinal direction thereof are enlarged, respectively. Is filled with an insulating material 601 to prevent electrical leakage. Further, as is apparent from FIGS. 10 and 11, the width W1 of the individual electrode 105,
02 is the width w3 of the ink cavity 106.
The width W1 of the individual electrode is smaller than the width w2 of the piezoelectric body 102. On the other hand, in the longitudinal direction of the piezoelectric body 102, the piezoelectric body 102 is formed so as to slightly project from the opposite ends of the ink cavity 106 by ΔL1 and ΔL2. It is protruding.

According to the above structure, the piezoelectric member 102 made of PZT, which is as thin as 30 μm, can be easily formed on the elastic vibration plate 103. Therefore, a displacement of 0.2 μm can be obtained even with a low voltage of about 30V. As a result, sufficient characteristics as an ink jet print head could be secured.

In this embodiment, the process of forming the piezoelectric material, the electrode and the resistor material on the sintered elastic vibration plate has been described. When the piezoelectric material, electrode material, and resistor material are formed and then fired integrally, the thickness of the adhesive layer changes because the adhesive layer such as a polymer material does not intervene between the elastic diaphragm and the piezoelectric material. The variation in the ink droplet ejection characteristics due to the above can be greatly reduced.

The members located on the surface side of the ink cavity forming member 901, that is, the ink cavity forming member 901, the elastic vibration plate 103, the individual electrode 105, and the piezoelectric body 1
02 and the resistor can be formed by firing simultaneously, the size and the number of nozzles can be reduced, the shape management and inspection can be facilitated, and the cost can be reduced.

FIG. 12 shows another embodiment of the present invention. In this embodiment, a wiring pattern 122 for mounting an IC connected to an individual electrode is formed on the surface of an elastic vibration plate 3. A driver IC 121 for driving a piezoelectric body and a resistor 111 are formed on a wiring pattern 122. According to this embodiment, when the drive signals for the number of nozzles of the print head are supplied from the recording apparatus main body, the number of lines required for at least the number of nozzles is reduced to only the number of IC drive signals. The number of signal lines can be reduced.

[0032]

As described above, according to the present invention, an ink supply path forming member provided with an ink supply path for receiving ink supply from the outside and a nozzle for ejecting ink droplets, an elastically deformable elastic diaphragm An ink cavity forming member formed with an ink cavity pressurized through the ink passage forming member, wherein the ink cavity forming member is located inside the ink flow path forming member and one end of the ink supply path overlaps the ink cavity forming member. Since the ink cavity is extended to an area where the ink supply path is not extended, and one end of the ink cavity is located in a vertical relationship with the ink supply path, and the ink cavity is connected to the nozzle and the ink supply path via a communication flow path. In order to form a head by combining an ink supply path forming member and an ink cavity forming member formed separately, It is possible to improve the manufacturing yield of the head. After screen-printing a paste-like piezoelectric material corresponding to the ink cavities or transferring a green sheet-like piezoelectric material to the surface of the elastic diaphragm that faces each ink cavity, the piezoelectric elements are fixed by firing. This eliminates the need for attaching individual piezoelectric elements, thereby simplifying the manufacturing process.

[Brief description of the drawings]

FIG. 1 is a top view showing one embodiment of an ink jet print head of the present invention.

FIGS. 2 (a) and 2 (b) show A in FIG.
It is a figure which shows the cross-sectional structure in the -A line and the BB line.

FIGS. 3A and 3B are a top view showing an electrode forming step and a cross-sectional view taken along line AA, respectively, of the manufacturing process of the ink jet print head of the present invention.

FIGS. 4A and 4B are a top view and a cross-sectional view taken along line AA, respectively, showing a piezoelectric laminating step in the manufacturing process of the ink jet print head of the present invention.

FIGS. 5A and 5B are a top view and a cross-sectional view taken along line AA, respectively, showing a resistor mounting step in a manufacturing process of the ink jet print head of the present invention.

FIGS. 6A and 6B are a top view and a cross-sectional view taken along line AA, respectively, showing a process of forming a common electrode in the process of manufacturing the ink jet print head of the present invention.

FIGS. 7A and 7B are a top view and a side view, respectively, showing a manufacturing process of a piezoelectric body.

FIGS. 8A and 8B are a top view and a side view, respectively, showing a step of transferring a piezoelectric body.

FIGS. 9A and 9B are a top view and a side view showing a step of forming an upper electrode of a piezoelectric body, respectively.

FIG. 10 is an enlarged view showing a cross-sectional structure of another embodiment of the ink jet print head of the present invention in the direction in which the piezoelectric bodies are arranged.

FIG. 11 is an enlarged view showing a longitudinal sectional structure of a piezoelectric body of another embodiment of the ink jet print head of the present invention.

FIG. 12 is a top view showing another embodiment of the ink jet print head of the present invention.

FIG. 13 is a diagram showing an example of a conventional ink jet print head.

FIG. 14 is a diagram showing a drive circuit of the ink jet print head.

FIG. 15 is a diagram illustrating a driving circuit of the ink jet print head.

[Explanation of symbols]

 Reference Signs List 101 pressure generating member 102 piezoelectric body 103 elastic vibration plate 104 common electrode 105 individual electrode 106 ink cavity 107 nozzle plate 108 ink supply path 109 ink supply amount control nozzle 110 nozzle 111 resistor

Claims (3)

[Claims] An ink supply path forming member having an ink supply path for receiving supply of ink from outside and a nozzle for discharging ink droplets, and an ink cavity pressurized through an elastically deformable elastic diaphragm are formed. After paste-printed piezoelectric material corresponding to the ink cavity is screen-printed on the surface of the formed ink cavity forming member and the elastic vibration plate facing the ink cavity, or a green sheet-shaped piezoelectric body is transferred. And a piezoelectric body fixed by baking, wherein the ink cavity forming member is located inside the ink flow path forming member and one end of the ink supply path extends to a region not overlapping with the ink cavity forming member. And
And an ink-jet printhead in which one end side of the ink cavity is positioned so as to be in a vertical relationship with the ink supply path, and the ink cavity is connected to the nozzle and the ink supply path via a communication channel. . 2. An ink supply path forming member having an ink supply path for receiving ink supply from outside and a nozzle for discharging ink droplets, and an ink cavity pressurized through an elastically deformable elastic diaphragm. And a method for manufacturing an ink jet print head in which an ink cavity forming member having a piezoelectric body fixed to the surface of the elastic vibration plate and displaced corresponding to the ink cavity is laminated and fixed, comprising alumina, zirconia, or Baking a green sheet of a piezoelectric material to produce the elastic vibrating plate, forming a lower electrode on the surface of the elastic vibrating plate, and transferring or printing the surface of the lower electrode to the ink cavity. Forming a piezoelectric precursor by subjecting the elastic vibrating plate, lower electrode, and piezoelectric precursor to 1000 to 1000
Baking at 1200 ° C., a method for manufacturing an ink jet print head. 3. An ink supply path forming member having an ink supply path for receiving ink supply from outside and a nozzle for discharging ink droplets, and an ink cavity pressurized through an elastically deformable elastic diaphragm. And a method for manufacturing an ink jet print head in which an ink cavity forming member having a piezoelectric body fixed to the surface of the elastic vibration plate and displaced corresponding to the ink cavity is laminated and fixed, comprising alumina, zirconia, or Manufacturing a green sheet of a piezoelectric material; forming a lower electrode on the surface of the green sheet; and forming a precursor of a piezoelectric body corresponding to the ink cavity by transfer or printing on the surface of the lower electrode. A process, wherein the green sheet, the lower electrode, and the precursor of the piezoelectric body are 100
Baking at a temperature of 0 to 1200 ° C.