JP2002248758A - Ink-jet recording head and ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording head having an ink supply path formed in an appropriate length, and an ink-jet recording apparatus. SOLUTION: An ink supply path 12 is formed in a nozzle plate 10 with a plurality of nozzle openings 11 formed, for supplying an ink to each pressure generating chamber 31 formed in a channel forming substrate 30. Thereby, since the ink supply path formed in the nozzle plate is not influenced by applying a polishing process to the channel forming substrate so as to be thinned, the length of the ink supply path can be provided by an appropriate value. Therefore, the ink can be supplied to the pressure generating chamber without excess or shortage as well as a good vibration damping characteristic of the ink in the pressure generating chamber can be provided so as to raise the driving frequency of a recording head for achieving highly fine recording.

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 for pressurizing ink stored in a pressure generating chamber and discharging the ink as ink droplets from nozzle openings, and an ink jet for printing information on a recording medium using the head. The present invention relates to an expression recording device.

[0002]

2. Description of the Related Art In general, an ink jet recording head communicates with a nozzle opening and the nozzle opening.
The pressure generating chamber has a substantially rectangular parallelepiped pressure generating chamber partially constituted by a diaphragm, and a piezoelectric element connected to the diaphragm of the pressure generating chamber. In such a configuration, information is recorded on the recording medium by driving and displacing the piezoelectric element to deform the diaphragm, pressurizing the ink stored in the pressure generating chamber and discharging the ink as ink droplets from the nozzle openings. It is supposed to.

As the ink jet type recording head, a type using a longitudinal vibration mode piezoelectric element which expands and contracts in the axial direction has been put to practical use. According to the ink jet recording head of this type, the volume of the pressure generating chamber can be changed by bringing the end face of the piezoelectric element into contact with the diaphragm, so that it can be suitable for high-density printing. However, in the manufacturing process of disposing the piezoelectric element on the diaphragm, the piezoelectric element is cut into a comb shape in accordance with the arrangement pitch of the nozzle openings, and the cut and divided piezoelectric element is positioned and fixed in the pressure generating chamber. There is a problem that difficult work is required.

On the other hand, as another type of ink jet recording head, a type using a flexural vibration mode piezoelectric element has been put to practical use. According to the ink jet recording head of this type, the piezoelectric element can be disposed on the diaphragm by a relatively simple operation of merely sticking and firing a green sheet made of a piezoelectric material in accordance with the shape of the pressure generating chamber and firing the green sheet. Therefore, the above problem can be solved.
However, since the flexural vibration is used, a certain area of the piezoelectric element is required, and there is a problem that high-density arrangement is difficult.

In order to solve this problem, an ink jet recording head utilizing a film forming technique has been proposed. That is, a piezoelectric material layer is formed uniformly over the entire surface of the vibration plate, and this piezoelectric material layer is cut into a shape corresponding to the pressure generation chambers by lithography, and the piezoelectric elements are formed independently for each pressure generation chamber. I do. According to this, the piezoelectric element can be disposed on the diaphragm by a precise and simple method called lithography, so that the work of attaching the piezoelectric element to the diaphragm becomes unnecessary, and the thickness of the piezoelectric element is further reduced. There is an advantage that high-speed driving becomes possible.

FIG. 6 is a schematic sectional view showing an ink jet recording head utilizing a conventional film forming technique. In this ink jet recording head, a flow path forming substrate 3 having a piezoelectric element 2 formed on a nozzle plate 1 is joined, a reservoir forming substrate 4 is joined on the flow path forming substrate 3, and the reservoir forming substrate 4 A sealing plate 5 and a drive circuit (driver IC) 6 for the piezoelectric element 2 are joined thereon, and these are covered with a case head 7.

The pressure generating chamber 3a and the ink supply path 3b for supplying ink to the pressure generating chamber 3a are formed in the flow path forming substrate 3, and the pressure generating chamber 3a is formed in the nozzle plate 1.
There is formed a nozzle opening 1a for discharging ink stored therein as ink droplets. And the pressure generating chamber 3
a is formed by half-etching the flow path forming substrate 3, the ink supply path 3 b is formed by polishing the flow path forming substrate 3 after the half-etching, and the nozzle opening 1 a is formed by the nozzle plate 1. Is formed by half-etching.

[0008]

In the case of increasing the density of an ink jet recording head utilizing the above-mentioned conventional film forming technique, for example, as shown in FIG.
The flow path forming substrate 3 having a thickness of about 70 μm, for example, having a thickness t2 of about 70 μm as shown in FIG. However, FIG.
The pressure generating chamber 3 formed in the flow path forming substrate 3 as shown in FIG.
Since the side surface 3aa of a is half-etched on the slope,
If the above polishing is performed, the length 1 of the ink supply path 3b becomes longer than necessary as shown in FIG.

If the length 1 of the ink supply path 3b becomes longer than necessary, a situation in which the supply of ink to the pressure generating chamber 3a becomes insufficient tends to occur. Further, the pressure generating chamber 3a
However, the vibration damping characteristics of the ink inside the ink cartridge deteriorate, that is, the vibration damping time becomes longer, which makes it difficult to increase the driving frequency of the piezoelectric element to perform high-definition printing.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet recording head and an ink jet recording apparatus having an ink supply path formed in an appropriate length. It is in.

[0011]

In order to achieve the above object, in the ink jet recording head according to the first aspect of the present invention, a nozzle plate having a plurality of nozzle openings is provided;
A flow path forming substrate formed with a plurality of pressure generating chambers each communicating with the nozzle opening, and an ink jet type that pressurizes the ink stored in the pressure generating chamber and discharges the ink as ink droplets from the nozzle opening. In the recording head, an ink supply path for supplying the ink to each of the pressure generating chambers is formed in the nozzle plate.

Thus, even if the flow path forming substrate is thinly polished, it does not affect the ink supply path formed in the nozzle plate, so that the length of the ink supply path can be set to an appropriate value. Therefore, ink can be supplied to the pressure generating chamber without excess and deficiency, and the vibration damping characteristics of the ink in the pressure generating chamber can be improved to increase the driving frequency of the recording head to perform high-definition recording.

According to a second aspect of the present invention, in the ink jet recording head according to the first aspect, the ink supply path is opposite to one longitudinal end of the pressure generating chamber corresponding to the arrangement of the nozzle openings. The width is formed so that the width on the supply inlet side to the pressure generating chamber is smaller than the width on the supply outlet side. Accordingly, the flow path resistance on the supply inlet side to the pressure generating chamber increases, so that the vibration damping characteristics of the ink in the pressure generating chamber can be improved.

According to a third aspect of the present invention, in the ink jet recording head according to the first or second aspect, the ink supply path is one of the nozzle plates in the nozzle plate in which two plates made of different materials are bonded to each other. It is characterized by being formed on a plate material. Thus, since the etching rates of the respective plate members are different, the ink supply path can be formed with high accuracy only on one of the plate members.

To achieve the above object, an ink jet recording apparatus according to a fourth aspect of the present invention includes the ink jet recording head according to any one of the first to third aspects,
It is characterized in that information is printed on a recording medium using the head. Accordingly, it is possible to provide a recording device that performs the above-described operations.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing an example of the configuration of an ink jet printer which is one of the ink jet recording apparatuses according to the embodiment of the present invention. In this ink jet printer, an ink jet print (recording) head 100, a head driving mechanism 102, and an automatic sheet feeder (automatic continuous paper feed mechanism) 103 are provided in a main body 101, and a tray 104 is provided at the upper rear of the main body 101. Have been.

Ink jet print head 100
Is provided with a total of four color ink cartridges 105, for example, yellow, magenta, cyan, and black, and is configured to be capable of full-color printing. The ink ejection timing of the inkjet print head 100 and the scanning of the head drive mechanism 102 are controlled by a dedicated controller board or the like built in the main body 101, and high-precision ink dot control, halftone processing, and the like are executed. It has become.

The recording paper 106 fed to the tray 104 is automatically sent out by the automatic sheet feeder 103 and is discharged from a paper discharge port 107 provided on the front of the main body 101. . As the recording paper 106, plain paper, special paper, recommended OHP sheet, glossy paper, glossy film, label sheet, postcard made by government, etc. can be used.

FIG. 2 is an exploded perspective view showing a schematic configuration example of the ink jet print head 100 of FIG. In this figure, only one color head is shown for convenience. In the ink jet type print head 100, a flow path forming substrate 30 in which the piezoelectric element 20 is formed on the nozzle plate 10 is joined, and a reservoir forming substrate 40 is joined on the flow path forming substrate 30 to form a reservoir. A sealing plate 50 and a drive circuit (driver IC) 60 for the piezoelectric element 20 are joined on the substrate 40, and these are covered with a case head 70.

FIG. 3 is a sectional view showing details when the ink jet print head 100 of FIG. 2 is assembled. In this figure, only the head for one color is shown for convenience. The nozzle plate 10 has a thickness of, for example, 0.1
It is made of a silicon single crystal substrate having a plane orientation of (100) mm to 1 mm. As shown in FIG. 3, a plurality of nozzle openings 11 arranged in two rows are formed in the nozzle plate 10 by anisotropic etching. Further, on the side of the nozzle plate 10 facing the flow path forming substrate 30, an ink supply path 12, which is a characteristic part of the present invention and is divided by a plurality of partition walls, which will be described in detail later, is anisotropically etched. Is formed.

The material of the nozzle plate 10 has a thickness of, for example, 0.1 mm to 1 mm and a plane orientation of (10
0) The thickness is, for example, 0.1 mm to 1 mm and the coefficient of linear expansion is, for example, 3 mm.
It may be made of glass ceramics, non-rust steel, or the like having a temperature of not more than 00 ° C and 2.5 to 4.5 (× 10 ⁻⁶ / ° C).

The flow path forming substrate 30 has a thickness of, for example, 150
It is made of a silicon single crystal substrate having a thickness of from μm to 300 μm and a plane orientation of (110). As shown in FIG. 3, the surface of the flow path forming substrate 30 facing the nozzle plate 10 is formed as an opening surface, and the surface of the flow path forming substrate 30 facing the reservoir forming substrate 40 has a thickness of silicon dioxide previously formed by thermal oxidation. An elastic film (not shown) of 1 μm to 2 μm is formed, and a piezoelectric element 20 is further formed as shown in FIG.

As shown in FIG. 3, pressure generating chambers 31 defined by a plurality of partition walls are arranged in the width direction on the opening surface of the flow path forming substrate 30 by anisotropic etching. As shown in FIG. 2 and FIG. 3, a communication part 32 that forms a part of a reservoir 80 that communicates with a reservoir part 41 of a reservoir forming substrate 40 to be described later and serves as a common ink chamber of each pressure generation chamber 31 is formed. Formed by anisotropic etching,
One end of each pressure generating chamber 31 in the longitudinal direction is communicated with an ink supply path 12 provided in the nozzle plate 10.

As shown in FIG. 3, the nozzle plate 10 is located on the opening side of the flow path forming substrate 30 and the nozzle opening 11 is located at one longitudinal end of the pressure generating chamber 31. Ink supply path 1 at the other end in the longitudinal direction of
2 is fixed via an adhesive, a heat welding film or the like so as to be positioned. For this reason, the nozzle plate 10
One of the surfaces also functions as a reinforcing plate that entirely covers one surface of the flow path forming substrate 30 and protects it from impact and external force. The nozzle plate 10 and the flow path forming substrate 30 are formed of the same material as a silicon single crystal substrate, and the nozzle plate 10 and the flow path forming substrate 30 have the same deformation due to heat. It is possible to easily and surely join using an adhesive or the like.

On the other hand, as shown in FIGS. 2 and 3, the lower electrode film having a thickness of about 0.2 μm For example, about 1
A piezoelectric element 20 composed of a piezoelectric layer having a thickness of μm and an upper electrode film having a thickness of, for example, about 0.1 μm is laminated by a thin film forming process. Generally, one of the electrodes of the piezoelectric element 20 is used as a common electrode, and the other electrode and the piezoelectric layer are patterned for each of the pressure generating chambers 31. And
The lead electrode 21 extends from the vicinity of one longitudinal end of the upper electrode film of the piezoelectric element 20 to a region facing the peripheral wall of the pressure generating chamber 31.

The reservoir forming substrate 40 has a thickness of, for example, 1
It is made of a silicon single crystal substrate having a size of 50 μm to 300 μm and a plane orientation of (110). Thus, similarly to the case of the nozzle plate 10 described above, the flow path forming substrate 30 and the reservoir forming substrate 40 can be easily and reliably bonded using a thermosetting adhesive or the like.

As shown in FIGS. 2 and 3, the reservoir forming substrate 40 communicates with a part of a reservoir 80 which serves as a common ink chamber for the pressure generating chambers 31 of the flow path forming substrate 30 described above. The reservoir section 41 communicating with the section 32 is arranged in the width direction by anisotropic etching. As shown in FIG. 3, an ink introduction path 42 communicating with an ink introduction port 51 of a sealing plate 50 described later is anisotropic. It is formed by reactive etching.

The piezoelectric element 2 of the reservoir forming substrate 40
In the area corresponding to 0, as shown in FIG.
A sealable space 43 is formed by anisotropic etching so as not to hinder the movement of zero, and a communication hole (not shown) for communicating the space 43 with the outside is provided by anisotropic etching. In addition, a drive circuit 60 and a wiring pattern 61 for the piezoelectric element 20 are provided on the surface opposite to the surface on which the space 43 is formed, as shown in FIGS.

The space 43 is filled and sealed with a drying fluid such as an inert gas through a communication hole. The inside of this space 43 is sealed at a pressure lower than the atmosphere,
Thus, the piezoelectric element 20 is securely sealed in the dry fluid atmosphere and is isolated from the external environment. As the drying fluid, a reducing gas can be used in addition to the inert gas. Conversely, by including an oxidizing gas, an environment for preventing the deterioration of the piezoelectric layer can be formed. . When such an inert gas is used, it is desirable to reduce the vapor pressure (partial pressure) of water therein as much as possible.

As shown in FIGS. 2 and 3, between the reservoir 41 of the reservoir forming substrate 40 and the formation of the space 43, the drive circuit 60
And a plurality of wirings 6 penetrating the lead surface 21 of the piezoelectric element 20 and the drive circuit 60.
A through-groove 44 through which 2 passes is formed by anisotropic etching.

The sealing plate 50 is made of, for example, a laminate of a PPS film and a stainless steel plate. This sealing plate 5
0 has a role of sealing the reservoir 80. Also,
As shown in FIG. 3, the ink introduction slot 51 communicating with the ink introduction path 42 of the reservoir forming substrate 40 is formed on the sealing plate 50 as described above. The case head 70 has a role of covering and protecting the above-described components, and forming a space for injecting the sealing resin 71 of the drive circuit 60 and the wiring 62 as shown in FIG.

FIGS. 4A and 4B are a sectional view and a plan view showing the nozzle plate 10 and the flow path forming substrate 30 around the pressure generating chamber 31. FIG. A nozzle opening 11 is perforated at a position corresponding to one longitudinal end of the pressure generating chamber 31 in the nozzle plate 10, and an ink supply path 12 is formed at a position corresponding to the other longitudinal end of the pressure generating chamber 31. Have been. The ink supply path 12 is formed such that the width w1 on the supply inlet side to the pressure generating chamber 31 is smaller than the width w2 on the supply outlet side.

As described above, since the ink supply path 12 is formed on the nozzle plate 10 side instead of the conventional flow path forming substrate side, even if the flow path forming substrate 30 is thinly polished, the nozzle plate 10 Ink supply path 12 formed in
Has no effect. Therefore, the ink supply path 12
Can be set to an appropriate value, so that ink can be supplied to the pressure generating chamber 31 without excess or deficiency.

Further, since the width of the ink supply path 12 is formed so that the supply outlet side is wider than the supply inlet side to the pressure generating chamber 31, the flow resistance on the supply inlet side to the pressure generating chamber 31 is reduced. Can be increased. Therefore, the vibration damping characteristics of the ink in the pressure generating chamber 31 can be improved, and the driving frequency of the inkjet print head 100 can be increased to perform high-definition recording.

FIGS. 5A and 5B are a cross-sectional view and a plan view showing a nozzle plate 10 'and a flow path forming substrate 30 around the pressure generating chamber 31 in a different form from FIG. The nozzle plate 10 'in this example is composed of two plate members 13 and 14 made of different kinds of materials bonded by an adhesive. The ink supply path 12 ′ is
0 ′, that is, one plate 13, that is, the flow path forming substrate 3
It is formed on the plate 13 on the 0 side. This ink supply path 1
2 ′ is also formed such that the width w1 ′ on the supply inlet side to the pressure generating chamber 31 is smaller than the width w2 ′ on the supply outlet side.

The ink supply path 12 'is formed by bonding the two plates 13 and 14 with an adhesive and then anisotropically etching only the plate 13. The plate material 13 on which the ink supply path 12 'is formed has a thickness of, for example, 0.05 mm to 0.5 mm and a plane orientation of (10
The plate member 14 is made of, for example, a stainless plate having a thickness of, for example, 0.05 mm to 0.5 mm. The plate 13 is not limited to a silicon single crystal substrate, and a metal plate other than a stainless steel plate can be used. As described above, since the type of each of the plate members 13 and 14 is different, the etching rate is also different.
Can be formed on only one of the plate members 13 with high accuracy.

In the above-described embodiment, a printer has been described as an example. However, the present invention is not limited to this, and the present invention is also applicable to an ink jet recording apparatus such as a facsimile apparatus and a copying apparatus.

As described above, the present invention has been described with respect to various embodiments. However, the present invention is not limited to the above embodiments, and other embodiments may be included within the scope of the invention described in the claims. It goes without saying that also applies.

[0040]

As described above, according to the ink jet recording head and the ink jet recording apparatus of the present invention, the ink supply path formed in the nozzle plate is formed even when the flow path forming substrate is thinly polished. Since there is no influence, the length of the ink supply path can be set to an appropriate value. Therefore, ink can be supplied to the pressure generating chamber without excess and deficiency, and the vibration damping characteristics of the ink in the pressure generating chamber can be improved. Therefore, it is possible to perform high-definition recording by increasing the driving frequency of the recording head.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration example of an ink jet printer which is one of the ink jet recording apparatuses according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a schematic configuration example of the inkjet print head of FIG.

FIG. 3 is a sectional view showing details when the ink jet print head of FIG. 2 is assembled.

FIG. 4 is a cross-sectional view and a plan view showing a nozzle plate and a flow path forming substrate around a pressure generating chamber of the ink jet print head of FIG. 2;

5A and 5B are a cross-sectional view and a plan view showing a nozzle plate and a flow path forming substrate around a pressure generating chamber in another form of the ink jet recording head of FIG. 2;

FIG. 6 is a schematic sectional view showing an ink jet recording head using a conventional film forming technique.

FIG. 7 is a cross-sectional view for explaining a problem of an ink jet recording head using a conventional film forming technique.

[Explanation of symbols]

10, 10 'Nozzle plate 11 Nozzle opening 12, 12' Ink supply path 13, 14 Plate material 20 Piezoelectric element 30 Flow path forming substrate 31 Pressure generating chamber 32 Communication part 40 Reservoir forming substrate 41 Reservoir part 42 Ink introducing path 43 Space 44 Penetration Groove 50 Sealing plate 51 Ink inlet 60 Drive circuit (driver IC) 70 Case head 71 Sealing resin 80 Reservoir 100 Inkjet printhead 101 Main body 102 Head drive mechanism 103 Auto sheet feeder (automatic continuous paper feed mechanism) 104 Tray 105 Ink cartridge 106 recording paper 107 paper exit

Claims (4)

[Claims] A nozzle plate having a plurality of nozzle openings formed therein; and a flow path forming substrate having a plurality of pressure generation chambers respectively connected to the nozzle openings, and stored in the pressure generation chamber. An ink jet recording head that pressurizes the ink and discharges the ink as ink droplets from the nozzle openings, wherein an ink supply path for supplying the ink to each of the pressure generating chambers is formed in the nozzle plate. Type recording head. 2. The ink supply path, wherein a width of a supply inlet side to the pressure generation chamber is opposite to a longitudinal end of the pressure generation chamber corresponding to an arrangement of the nozzle opening, and the width of the supply inlet side is the supply outlet. 2. The ink jet recording head according to claim 1, wherein the ink jet recording head is formed to have a width smaller than a width of the side. 3. The ink-jet apparatus according to claim 1, wherein the ink supply path is formed in one of the plate members of the nozzle plate in which two plate members made of different materials are adhered to each other. Type recording head. 4. An ink jet recording apparatus comprising the ink jet recording head according to claim 1, and printing information on a recording medium using the head.