JP2002307692A - Ink jet head and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solidly maintain an adhesion state of a cover plate and a nozzle plate to an upper face and a front face of a substrate without complicating a manufacturing process, and surely protect an electrode film formed inside an ink chamber from ink. SOLUTION: A plurality of grooves 2 are formed to the upper face of the substrate 1, and electrodes 4 are formed to upper parts of inner side faces of partition walls 3 in each groove 2. The cover plate 5 is bonded via an adhesive to the upper face of the substrate 1. Thereafter, parylene films 6 are formed to two side faces, an upper face and a bottom face inside the ink chamber constituted of the groove 2. The parylene film 6 is surely formed also to a corner formed by an upper end of the electrode 4 and an inner side face of the cover plate 5 in the ink chamber 2, and therefore the electrode 4 is prevented from contacting the ink even partially and being eroded by the ink. Moreover, the ink is prevented from invading a joint between an upper face of the partition wall 3 and the upper end of the electrode 4 at the cover plate 5, so that the adhesive used for jointing the cover plate 5 is prevented from being eroded by the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure vibration generated in an ink chamber due to a shear deformation of a partition when a driving voltage based on image data is applied to an electrode formed on an inner surface of the partition in the ink chamber. The present invention relates to an ink jet head that forms an image by discharging ink from nozzles, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, non-impact printing apparatuses, such as an ink jet system, which are suitable for colorization and multi-gradation, have rapidly spread in place of impact printing apparatuses. In particular, since it is advantageous in terms of printing efficiency, manufacturing cost, running cost, etc., a drop-on that discharges the necessary ink only at the time of printing by the Kaiser method using a piezoelectric element or the thermal jet method using a heating element, etc.・ Demand type is the mainstream.

Here, the Kaiser system in which a part of a wall constituting the ink chamber is deformed to discharge ink by a change in volume of a piezoelectric element disposed outside the ink chamber is difficult to miniaturize and is suitable for high resolution. Absent. In the thermal jet method in which ink is ejected by the pressure of bubbles generated in the ink in the ink chamber due to heating of the heating element, the demand for durability of the ink becomes severe because the ink is repeatedly heated / cooled, Long life and power consumption.

Therefore, as an ink-jet type ink-jet head which solves these drawbacks, for example, as described in JP-A-63-247051, a shear deformation of a piezoelectric material constituting an ink chamber causes the ink chamber to have an ink chamber. There is a method using a method in which ink is ejected by applying pressure vibration to the ink. In this method, a plurality of groove-shaped ink chambers are formed on a piezoelectric material substrate with a partition therebetween, and a driving voltage is applied to an electrode formed on an inner side surface of the partition in the ink chamber to shear the piezoelectric material partition. In this mode, the ink is ejected by using the pressure vibration generated in the ink filled in the ink chamber, and the density of the nozzles is reduced, the power consumption is reduced, and the driving voltage is increased in frequency. Suitable for.

An ink jet head using a substrate made of a piezoelectric material is, for example, as shown in FIG. 4, a flat plate is formed on the upper surface of a substrate 51 having a plurality of grooved ink chambers 52 with a partition wall 53 interposed therebetween. A nozzle plate 56 provided with nozzles 55 corresponding to the respective ink chambers 52 is joined to the front surface of the substrate 51 while joining a cover plate 54 having a rectangular shape. In order for the ink discharged from the nozzles 55 to adhere to the paper surface in a stable state, it is necessary that the outer surface of the nozzle plate 56 facing the paper surface to which the ink has adhered has liquid repellency. Therefore, at least the outer surface of the nozzle plate 55 is coated with a material having liquid repellency. As this material, for example, polyparaxylylene (registered trademark: Parylene: hereinafter, referred to as parylene) is used. Parylene is a polymer that is chemically inert, has high stability to hydrolysis, has low hygroscopicity, and has characteristics such as low diffusion rates of humidity and oxygen.

However, although a polymer such as parylene is excellent in liquid repellency, it is poor in adhesiveness to other materials due to low surface energy, and parylene is also provided on the surface of the nozzle plate 56 facing the front surface of the substrate 51. When the nozzle plate 56 is coated, the nozzle plate 56 cannot be securely joined to the front surface of the substrate 51.

Therefore, Japanese Patent Application Laid-Open No. 9-193404 discloses a technique in which a metal material for improving adhesion is coated on the surface of the nozzle plate 56 facing the front surface of the substrate 51 coated with parylene. ing. For example, as shown in FIG. 5, a parylene film 58 is formed on the entire surface of a core 57 made of nickel by chemical vapor deposition.
Is formed, a 5 to 50 nm tantalum layer 59 is formed on the surface facing the front surface of the substrate and on the inner peripheral surface of the nozzle 55 by sputtering to form the nozzle plate 56.

Japanese Patent Application Laid-Open No. Hei 7-110068 discloses that a driving electrode formed on the inner surface of a partition in an ink chamber is protected from ink so that an ink jet head can be used stably for a long period of time. Manufacturing method is disclosed. As shown in FIG. 6, an electrode film 64 and a parylene film are formed on an upper surface of a piezoelectric material substrate 61 in which a plurality of groove-shaped ink chambers 62 parallel to each other are sandwiched between partition walls 63, as shown in FIG. 65 are formed in this order (FIG. 6A), and the electrode film 64 is protected from the ink by preventing deterioration of the ink in the ink chamber 62 and generation of bubbles due to electrolysis. An inorganic oxide film 66 such as silicon oxide is laminated thereon to secure the lyophilic property of the inner surface of the ink chamber 62 (FIG. 6B). This prevents air from entering the ink chamber 62 during ink injection. Next, the upper surface of the partition 63 in the substrate 61 is polished to polish the inorganic oxide film 66, the parylene film 65, and the electrode film 64.
After removing the cover plate 67, the cover plate 67 is bonded (FIG. 6).
(C)). Thereafter, the nozzle plate 6 is provided on the front surface of the substrate 61.
8 (FIG. 6D).

[0009]

However, in the configuration disclosed in Japanese Patent Application Laid-Open No. HEI 9-193404, after a parylene film is once formed on the entire surface of the nozzle plate, the surface of the nozzle plate facing the front surface of the substrate. Is coated with tantalum to improve adhesion, a sputtering process is required, and there is a problem that the manufacturing time becomes longer and the manufacturing equipment becomes larger.

On the other hand, in the configuration disclosed in Japanese Patent Application Laid-Open No. 7-101068, the electrode film, the parylene film, and the inorganic oxide film are removed from the upper surface of the partition wall between the ink chambers on the substrate by polishing. The inorganic oxide film and the parylene film are easily peeled off at the upper end of the inner side surface of the partition wall, and in particular, the parylene film having liquid repellency cannot be securely bonded to the cover plate via an adhesive. As shown in FIG. 7, the ink filled in the ink chamber 62 flows between the upper end surface of the parylene film 65 formed on the inner surface of the partition 63 and the adhesive 69 applied on the inner surface of the cover plate 67. Then, there is a problem that the electrode film 64 penetrates into the electrode film 64 side through the contact hole and cannot reliably protect the electrode film 64 from ink.

Further, since the parylene film and the inorganic oxide film are not formed on the upper surface of the substrate to which the cover plate is bonded, the parylene film and the inorganic oxide film are also formed on the front surface of the substrate to which the nozzle plate is bonded to ensure flatness. No inorganic oxide film should be formed. Therefore, an electrode film for the substrate,
It is necessary to perform a masking process on the front surface of the substrate when the parylene film and the inorganic oxide film are formed, or to perform a polishing process on the front surface of the substrate after forming the electrode film, the parylene film, and the inorganic oxide film. There is a problem that the manufacturing process becomes complicated. Further, when a mechanical force due to polishing or cutting acts on the end surface of the parylene film on the upper surface side of the substrate, there is a problem that the parylene film is peeled off from the film formation surface.

An object of the present invention is to make it possible to maintain the adhesion state of the cover plate and the nozzle plate to the upper surface and the front surface of the substrate firmly without complicating the manufacturing process, and to improve the electrode film formed in the ink chamber. An object of the present invention is to provide an ink jet head that can be reliably protected from ink and a method for manufacturing the same.

[0013]

The present invention has the following arrangement as means for solving the above-mentioned problems.

(1) A plurality of grooves are formed on the upper surface of the piezoelectric material substrate with a partition therebetween, and an electrode is formed on the upper end side of the inner surface of the partition in each groove, and a cover plate is formed on the upper surface of the substrate. In an ink jet head having a nozzle plate joined to the front surface, a polymer coat film is provided on at least the inner surface of each groove including the joint with the upper surface of the partition and the upper end of the electrode on the inner surface of the cover plate. .

In this configuration, a polymer coat film is formed on the two side surfaces, the upper surface, and the bottom surface of the inside of the ink chamber which is formed by the groove whose upper surface is closed by the cover plate. Therefore, the two side surfaces, the upper surface, and the bottom surface of the ink chamber are protected from the ink, and the ink is reliably prevented from coming into contact with the corner formed by the upper end of the electrode and the upper surface of the ink chamber.

(2) The nozzle plate is bonded to the front surface of the substrate and the front end of the electrode with a polymer coat film interposed therebetween.

In this configuration, a polymer coat film is interposed between the electrode in the ink chamber and the nozzle plate.
Therefore, even when the electrode is insulated from the nozzle plate by the polymer coat film, and the nozzle plate is formed of a conductive material, the inkjet head can be accurately driven by applying the driving voltage to the electrode.

(3) The joint portion between the nozzle plate and the front surface of the substrate is characterized in that a polymer coat film is present at least at a corner formed by the inner surface of the nozzle plate and the front end of the groove of the substrate.

In this configuration, the contact of the ink is reliably prevented even at the corner formed by the front end of the electrode and the front surface of the ink chamber formed by the inner surface of the nozzle plate.

(4) The exposed surface of the polymer coat film in the ink chamber has lyophilic property in the ink chamber.

In this configuration, the two side surfaces, the top surface, and the bottom surface of the inside of the ink chamber are covered with a lyophilic polymer coat film on the exposed surface. Therefore, the ink filled in the ink chamber comes into contact with the lyophilic surface of the polymer coat film.

(5) A groove forming step of forming a plurality of grooves on the substrate of the piezoelectric material with the partition wall interposed therebetween, an electrode forming step of forming an electrode on the upper end side of the inner side surface of the partition wall in each groove section, A cover plate joining step of joining the cover plates and a polymer coating step of forming a polymer coat film on the entire surface in each groove are performed in this order.

In this configuration, the two side surfaces, the upper surface, and the lower surface of the ink chamber formed by the cover plate joined to the upper surface of the partition and the upper end of the electrode are covered with a polymer coat film. Therefore, the two side surfaces, the upper surface, and the bottom surface of the ink chamber are protected from the ink, and the ink is reliably prevented from coming into contact with the corner formed by the upper end of the electrode and the upper surface of the ink chamber.

(6) After the polymer coating step, a nozzle plate joining step of joining a nozzle plate to the front surface of the substrate is performed.

In this configuration, the nozzle plate is joined to the front surface of the substrate with the front end of the electrode in the ink chamber covered with the polymer coat film. Therefore,
A polymer coat film is interposed between the front end of the electrode and the nozzle plate, the electrode is insulated from the nozzle plate by the polymer coat film, and a drive voltage is applied to the electrode even when the nozzle plate is formed of a conductive material. Thus, the inkjet head is accurately driven.

(7) A nozzle plate joining step of joining a nozzle plate to the front surface of the substrate is performed between the cover plate joining step and the polymer coating step.

In this configuration, the upper surface of the groove is closed by the cover plate joined to the upper surface of the partition and the upper end of the electrode, and the front surface of the groove is sealed by the nozzle plate joined to the front surface of the partition and the front end of the electrode. Is closed, the front face, the two side faces, the top face, and the bottom face of the ink chamber formed by the cover plate, the nozzle plate, and the groove are covered with the polymer coat film. Therefore, the two side surfaces, the top surface, and the bottom surface of the ink chamber are protected from ink, and the corner formed by the upper end of the electrode and the upper surface of the ink chamber, and the front end of the electrode and the front surface of the ink chamber are formed. The contact of the ink is reliably prevented in the entire range of the electrode including the corner portion to be formed.

(8) After the polymer coating step, a lyophilic step for lyophilic the exposed surface of the polymer coat film in the ink chamber is performed.

In this configuration, the exposed surface in the ink chamber of the polymer coat film covering the two side surfaces, the upper surface, and the bottom surface of the ink chamber is provided with lyophilicity. Therefore, the ink filled in the ink chamber comes into contact with the lyophilic surface of the polymer coat film.

[0030]

FIG. 1 is a perspective view showing a state before a nozzle plate joining step of an ink jet head according to a first embodiment of the present invention. The inkjet head 10 according to this embodiment is formed by the following procedure. First, a diamond blade or the like is formed on a top surface of a piezoelectric substrate 1 made of a piezoelectric ceramic material such as lead zirconate titanate (PZT) or lead titanate (PZ) which is polarized in a thickness direction. About 3 depth using
A plurality of grooves 2 having a width of about 100 μm and a width of about 100 μm are formed in parallel with each other with a partition wall 3 interposed therebetween.

Next, in the electrode forming step, a vapor deposition device,
Using a sputtering device or a plasma CVD device,
In the upper part of the inner side surface of the partition wall 3 in each groove 2, Cu,
A driving metal electrode 4 is formed by forming a conductive metal film such as Al, Cr, or Au to a thickness of about 1 μm. Thereafter, in the cover plate joining step, the upper surface of the substrate 1 is polished to remove unnecessary electrodes formed on the upper surface of the partition walls 3 and smoothed, and the cover plate 5 is bonded to this portion via an adhesive. I do.

Up to this step, a plurality of inkjet heads 10 are collectively performed in the longitudinal direction of the groove 2 on one piezoelectric material wafer, and the upper surface of the substrate 1 having the electrode 4 formed in the groove 2 Are cut out one by one at predetermined positions in the longitudinal direction of the groove 2 in a state where the cover plate 5 is joined to the groove 2. Therefore, the front end of the electrode 4 is
Is flush with the front surface 1a, which is the cut surface in FIG.

Next, in a polymer coating step, parylene, which is a polymer having liquid repellency, is deposited by chemical vapor deposition (CVD) on two side surfaces and an upper surface of an ink chamber formed by a groove 2 whose upper surface is closed by a cover plate 5. And a parylene film 6 is formed on the bottom surface so as to have a thickness of about 3 μm. At this time, the parylene film 6 is similarly formed on the front surface 1a of the substrate 1.

It is known that chemical vapor deposition allows parylene to penetrate into details and form a film with a uniform film thickness. Two side surfaces, an upper surface and a lower surface in the ink chamber (groove) 2 before the nozzle plate 7 is bonded. The parylene film 6 having a predetermined thickness can be easily formed on the entire surface of the substrate. In particular, the parylene film 6 is surely formed at the corner formed by the upper end of the electrode 4 and the inner surface of the cover plate 5 in the ink chamber 2.
When there is a gap between the inner surface of the electrode 4 and the parylene, the entire surface of the electrode 4 is completely covered with the parylene film 6 in the ink chamber 2 by the parylene entering the gap.

As a result, the electrode 4 does not come into contact with any part of the ink filled in the ink chamber 2 and is not eroded by the ink.
It is possible to reliably prevent the operation failure of the inkjet head 10 due to the deterioration of the ink jet head. In addition, it is possible to reliably prevent ink from entering the joint between the upper surface of the partition wall 3 and the upper end of the electrode 4 in the cover plate 5, and the adhesive used for joining the cover plate 5 is eroded by the ink. Therefore, the adhesive strength of the cover plate 5 to the substrate 1 can be maintained robust.

Further, in the lyophilic process, a hydroxyl group or a carbonyl group is generated on the exposed surface of the parylene film 6 by performing a plasma process using an ashing device or the like, and the lyophilic process is performed. This makes it possible for the entire surface of the ink chamber 2 covered with the parylene film 6 that is in contact with the ink to be made lyophilic, so that the occurrence of problems such as air mixing during ink injection into the ink chamber 2 is ensured. Can be prevented.

Finally, in the nozzle plate joining step, a flat plate made of a resin material such as polyimide or a metal material such as stainless steel is placed on a flat plate of 20 μm to 3 μm facing each ink chamber 2.
A nozzle plate 7 having a tapered nozzle 8 having an inner diameter of about 0 μm is bonded to the front surface 1a of the substrate 1 with an adhesive. At this time, since the front end of the electrode 4 is covered with the parylene film 6 of an insulating material together with the front surface 1a of the substrate 1, the inner surface of the nozzle plate 7 is
Is not electrically connected to the front end of the horn. Therefore,
Even when the nozzle plate 7 is formed of a conductive material, the insulation of the electrode 4 for each ink chamber can be ensured, and the inkjet head 10 can be accurately operated by applying a drive voltage to the electrode 4. be able to.

The front end of the electrode 4 and the front surface 1 of the substrate 1
The parylene film 6 covering a is also made lyophilic by plasma treatment at the same time as the parylene film 6 covering the inside of the ink chamber 2. Therefore, the adhesive used for bonding the nozzle plate 7 to the front surface 1a of the substrate 1 does not easily peel off from the parylene film 6, and the bonding strength between the front surface 1a of the substrate 1 and the nozzle plate 7 is maintained robust. You.

A liquid-repellent parylene film or another water-repellent film is previously formed on the outer surface of the nozzle plate 7 facing the image forming surface of the sheet on which the ink ejected from the nozzle 8 adheres. . As a result, ink adhered to the image forming surface of the sheet is not transferred to the outer surface of the nozzle plate 7, and a stable image forming state on the sheet is obtained.

FIG. 2 is a perspective view of an ink jet head according to a second embodiment of the present invention, showing a state where a part of a nozzle plate is cut away. The inkjet head 20 according to this embodiment is formed by the following procedure. First, in a groove processing step, a diamond blade or the like is placed on the upper surface of a piezoelectric substrate 11 made of a piezoelectric ceramic material such as lead zirconate titanate (PZT) or lead titanate (PZ) that has been polarized in the thickness direction. A plurality of grooves 12 having a depth of about 300 μm and a width of about 100 μm are formed in parallel with each other with a partition wall 13 interposed therebetween.

Next, in the electrode forming step, a vapor deposition device,
Using a sputtering device or a plasma CVD device,
The upper part of the inner side surface of the partition 13 in each groove 12 has C
A driving metal 14 is formed by forming a conductive metal film such as u, Al, Cr, or Au to a thickness of about 1 μm. Thereafter, in the cover plate joining step, the substrate 1
By polishing the upper surface of 1, unnecessary electrodes formed on the upper surface of the partition 13 are removed and smoothed, and the cover plate 15 is bonded to this portion via an adhesive.

Thereafter, in a nozzle plate bonding step, a flat plate made of a resin material such as polyimide or a metal material such as stainless steel is placed on a flat plate of 20 μm
A nozzle plate 17 having a tapered nozzle 18 having an inner diameter of about 30 μm is placed on a front surface 11 a of a substrate 11.
Is bonded through an adhesive.

Further, in the polymer coating step, parylene which is a polymer having liquid repellency by chemical vapor deposition (CVD) is filled with a groove 12 having a top surface closed by a cover plate 15 and a front surface closed by a nozzle plate 17. Front, two sides, top and bottom, and nozzle plate 1
The parylene film 16 is formed on the outer surface of the substrate 7 so as to have a thickness of about 3 μm.

Finally, in the lyophilic step, the parylene film 16 on the outer surface of the nozzle plate 17 is protected by a resist or the like, and is subjected to plasma processing using an ashing device or the like, so that the exposed surface of the parylene film 16 is exposed. A hydroxyl group or a carbonyl group is generated and subjected to lyophilic treatment.

In this manner, as shown in FIG. 3A, the front surface, the two side surfaces, the top surface, and the bottom surface of the ink chamber (groove) 12 after the nozzle plate 17 is bonded, and the nozzle plate 17 The ink jet head 20 having the parylene film 16 having a predetermined thickness on the outer side surface can be easily formed.

In particular, a corner formed by the upper end of the electrode 14 in the ink chamber 12 and the inner side surface of the cover plate 15, and the front end of the electrode 14 and the nozzle plate 1
7 also has a parylene film 1 at the corner formed by the inner surface of
6 is reliably formed, and even if a gap exists between the upper end of the electrode 14 and the inner surface of the cover plate 15 or between the front end of the electrode 14 and the nozzle plate 17, When the parylene enters, the entire surface of the electrode 14 in the ink chamber 12 is completely covered with the parylene film 1.
6 coated.

Thus, the electrode 14 is connected to the ink chamber 12
Since the ink filled therein does not come into contact with any part and is not eroded by the ink, it is possible to more reliably prevent the malfunction of the inkjet head 20 due to the deterioration of the electrode 14. The substrate 1 in the cover plate 15 and the nozzle plate 17
1 can be reliably prevented from penetrating into the joint with the cover plate 1, the adhesive used for joining the cover plate 15 and the nozzle plate 17 to the substrate 11 is not eroded by the ink, and the cover plate 15 is not eroded. In addition, the adhesive strength between the nozzle plate 17 and the substrate 11 can be maintained robust.

Further, the entire surface of the ink chamber 12 covered with the parylene film 16 which comes into contact with the ink can be made lyophilic, thereby causing problems such as mixing of air when the ink is injected into the ink chamber 12. Can be reliably prevented.

Further, since the nozzle plate joining step is performed prior to the polymer coating step, the nozzle plate 1 is placed on the front end of the electrode 14 and the front surface 11a of the substrate 11.
7 are directly bonded via an adhesive. Therefore, the substrate 1
The adhesive 19 used for bonding the nozzle plate 17 to the front surface 11a of the first substrate 11 does not easily peel off from the front surface 11a of the substrate 11, and the bonding strength between the front surface 11a of the substrate 11 and the nozzle plate 17 is firmly maintained. .

In addition, since the parylene film 16 is formed on the outer surface of the nozzle plate 17 at the same time as the inside of the ink chamber 12 in the polymer coating step, the parylene film 16 or the like is previously formed on the outer surface of the nozzle plate 17. There is no need to form a film having water repellency. Further, during the lyophilic process for the parylene film 16 in the ink chamber 12, the parylene film 16 on the outer surface of the nozzle plate 17 is protected by a resist agent or the like.
0 can be simplified, and the ink attached to the image forming surface of the sheet is prevented from being transferred to the outer surface of the nozzle plate 7, and a stable image forming state can be obtained on the sheet.

By masking the outer surface of the nozzle plate 17 and the inner peripheral surface of the nozzle 18 during the polymer coating step and the lyophilic step, as shown in FIG. The ink chamber 12 on the side
It can also be coated with a liquid repellent material different from the inside.

In the first and second embodiments,
Although parylene was used as the polymer having liquid repellency, other polymers such as polyolefin, polyxylylene, or polymonochloroparaxylylene can also be used.

In the first and second embodiments, the plasma treatment is used in the lyophilic step.
The surface of the polymer having liquid repellency can also be made lyophilic by irradiation, corona discharge, ozone washing, or the like.

[0054]

According to the present invention, the following effects can be obtained.

(1) By forming a polymer coat film on the two side surfaces, the upper surface, and the bottom surface of the ink chamber formed by the groove whose upper surface is closed by the cover plate, the two side surfaces, the upper surface, and the bottom surface of the ink chamber are formed. In addition to being able to protect from the ink, the contact of the ink with the upper surface of the partition on the inner surface of the cover plate and the junction with the upper end of the electrode at the corner formed by the upper end of the electrode and the upper surface of the ink chamber is ensured. Thus, it is possible to reliably prevent the occurrence of operation failure due to the deterioration of the electrode eroded by the ink. Further, the adhesive used for joining the cover plate and the substrate is prevented from being eroded by the ink, and the adhesive strength between the cover plate and the substrate can be maintained robust.

(2) By interposing a polymer coat film between the electrode in the ink chamber and the nozzle plate, the electrode and the nozzle plate can be reliably insulated by the polymer coat film. Thus, even when the nozzle plate is formed of a conductive material, the insulation of the electrodes for each ink chamber can be ensured, and the inkjet head can be accurately driven by applying a drive voltage to the electrodes. .

(3) By coating the polymer on the entire area of the electrode including the corner formed by the front end of the electrode and the front surface of the inside of the ink chamber formed by the inner surface of the nozzle plate, the front surface of the substrate in the nozzle plate is formed. The contact of the ink in the ink chamber with the junction with the ink chamber can be reliably prevented.
Accordingly, it is possible to reliably prevent the ink from being in contact with the two side surfaces of the groove on the inner surface of the nozzle plate, the upper surface and the bottom surface of the partition wall, and the bonding portion with the front end of the electrode. Occurrence of operation failure due to deterioration can be prevented beforehand. Further, it is possible to prevent the adhesive used for joining the nozzle plate and the substrate from being eroded by the ink, and to maintain a strong adhesive strength between the nozzle plate and the substrate.

(4) By covering the two side surfaces, the top surface, and the bottom surface of the ink chamber with the lyophilic polymer coat film on the exposed surface, the ink filled in the ink chamber can be made to have the lyophilic property of the polymer coat film. Contact surface. Accordingly, it is possible to prevent air from being mixed when the ink is injected into the ink chamber, and to operate the inkjet head accurately.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state before a nozzle plate joining step of an inkjet head according to a first embodiment of the present invention.

FIG. 2 is a perspective view of an ink jet head according to a second embodiment of the present invention, showing a state where a part of a nozzle plate is cut away.

FIG. 3 is a plan sectional view showing a configuration of the inkjet head.

FIG. 4 is a perspective view showing a configuration of a first conventional example of an ink jet head.

FIG. 5 is a cross-sectional view illustrating a configuration of a main part of a second conventional example of an inkjet head.

FIG. 6 is a view showing a manufacturing method of the second conventional example.

FIG. 7 is a cross section showing a main part of the second conventional example.

[Explanation of symbols]

 1-substrate 1a-front surface 2-groove (ink chamber) 3-partition 4-electrode 5-cover plate 6 parylene film 7-nozzle plate 10-inkjet head

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C057 AF70 AF93 AG45 AP02 AP13 AP25 AP58 AP59 BA04 BA14

Claims (8)

[Claims] A plurality of grooves are formed on an upper surface of a substrate made of a piezoelectric material with a partition therebetween, and an electrode is formed on an upper end side of an inner side surface of the partition in each groove, and a cover plate is formed on an upper surface of the substrate. An ink jet head having a nozzle plate joined to a front surface thereof, wherein a polymer coat film is provided on at least the inner surface of each groove including a joint between the upper surface of the partition and the upper end of the electrode on the inner surface of the cover plate. head. 2. The ink jet head according to claim 1, wherein the nozzle plate is joined to a front surface of the substrate and a front end of the electrode with a polymer coat film interposed therebetween. 3. A joint portion between the nozzle plate and the front surface of the substrate, wherein a polymer coat film is present at least at a corner formed by an inner side surface of the nozzle plate and a front end of a groove of the substrate. 2. The inkjet head according to item 1. 4. The ink jet head according to claim 1, wherein an exposed surface of the polymer coat film in the groove has a lyophilic property in the groove. 5. A groove forming step of forming a plurality of grooves on a substrate made of a piezoelectric material with a partition wall interposed therebetween, an electrode forming step of forming an electrode on an upper end side of an inner side surface of the partition wall in each groove section, and a cover on an upper surface of the substrate. A method for manufacturing an ink jet head, comprising: a cover plate joining step of joining plates; and a polymer coating step of forming a polymer coat film on the entire surface of each groove portion in this order. 6. The method according to claim 5, wherein a nozzle plate joining step of joining a nozzle plate to a front surface of the substrate is performed after the polymer coating step. 7. The method according to claim 5, wherein a nozzle plate joining step of joining a nozzle plate to a front surface of the substrate is performed between the cover plate joining step and the polymer coating step. . 8. A method for manufacturing an ink jet head according to claim 5, wherein a lyophilic step of lyophilicizing the exposed surface of the polymer coat film in the groove is performed after the polymer coating step. .