JP2002103632A - Droplet discharge head, method of manufacturing the same, and ink jet recording apparatus - Google Patents

Abstract

(57) [Abstract] (with correction) [Problem] In joining a nozzle plate with a flow path substrate having a high degree of integration and a fine flow path formed to cope with high image quality and high speed recording, Provided are a droplet discharge head and a method of manufacturing the droplet discharge head, which reduce the amount of adhesive protruding and have high bonding reliability, and provide an ink jet recording apparatus capable of obtaining stable image quality. SOLUTION: A flow path substrate having a wettability improving layer 49 formed on a bonding surface and a nozzle plate 43 are bonded via an adhesive layer 105, and the nozzle plate 43 has uneven thickness on the bonding surface side.
05 changes along the uneven thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a droplet discharge head, a method of manufacturing the same, and an ink jet recording apparatus.

[0002]

2. Description of the Related Art For example, an ink jet head, which is one of the liquid drop ejection heads used in an ink jet recording apparatus used as an image recording apparatus (image forming apparatus) such as a printer, a facsimile, a copying machine, a plotter, etc., ejects ink droplets. Nozzle, a liquid chamber (also referred to as a pressurized chamber, a discharge chamber, a pressure chamber, a pressurized liquid chamber, etc.) with which the nozzle communicates, and energy generating means for generating energy for pressurizing the ink in the liquid chamber. By driving the energy generating means, the ink in the liquid chamber is pressurized to eject ink droplets as droplets from the nozzles.

Conventionally, as an ink jet head, a piezoelectric element is used to deform a diaphragm forming a wall surface of a liquid chamber to discharge ink droplets (Japanese Patent Laid-Open No. 2-5 / 1990).
JP-A No. 1734), or a method in which an ink droplet is ejected by pressure generated by heating ink in a liquid chamber using a heating resistor to generate air bubbles (Japanese Patent Application Laid-Open No. Sho 61-1986).
JP-A-59911), a diaphragm and an electrode forming a wall surface of a liquid chamber are arranged in parallel, and the diaphragm is deformed by an electrostatic force generated between the diaphragm and the electrode, thereby ejecting ink droplets. (Japanese Patent Laid-Open No. 6-71882)
And the like) are known.

The ink jet head has a liquid chamber, a fluid resistance section for supplying ink to the liquid chamber, a common ink liquid chamber for supplying the liquid chamber via the fluid resistance section, and a nozzle for discharging ink droplets. It is necessary to form various flow paths such as holes or nozzle grooves. For example, a flow path substrate (liquid chamber substrate) for forming a flow path such as a liquid chamber is joined to a member such as a nozzle plate having a nozzle. A head is formed.

Conventionally, members constituting an ink-jet head are generally joined by an adhesive such as a wet adhesive or a film adhesive. In addition, a silicon substrate is used for a liquid chamber substrate and a nozzle plate. In such cases, direct bonding, eutectic bonding via a metal material, or anodic bonding when a metal material is used, are also performed.

[0006] In general, when two members are joined, there is a demand that the accuracy of the components be maintained and the joining be performed with high reliability. However, the inkjet head component has a high degree of integration in order to cope with high image quality and high speed recording, and a fine flow path is formed. For this reason, when the adhesive bonding is performed, if the flow path is closed or the shape of the adhesive is varied due to the protrusion of the adhesive, the ejection characteristics of the head are varied, thereby deteriorating the image quality.

Therefore, as a countermeasure against this, a method has been used in which a gap agent is mixed to suppress the amount of crushing. However, when a gap agent is used for ordinary joining, it is about 1.5 times the diameter of the gap agent. It is said that a coating film thickness of is required, so that one-third of the coating amount protrudes,
There is a limit to the reduction of protrusion.

Therefore, there is a method of reducing the thickness of the adhesive layer itself in order to reduce the protrusion of the adhesive. Also, as disclosed in Japanese Patent Application Laid-Open No. Hei 5-330067, a joining method in which an escape groove for the adhesive is formed in a portion other than the groove of the flow path plate so that the protruding adhesive escapes to the escape groove. Alternatively, as disclosed in JP-A-10-291323, a uniform gap is formed between two substrates (members), and the gap is filled with an adhesive having a low viscosity by utilizing surface tension. And a method of joining them together.

[0009]

By the way, in order to perform thin-film bonding with a thin adhesive layer, it is required to improve the precision of the bonding surface, and it can be applied only to bonding between extremely flat materials such as Si. This is a problem. Conventional thin film bonding has been about 5 to 10 μm, and this bonding layer (adhesive layer) has absorbed the thickness variation of a thin layer member of about several μm, thus enabling bonding. However, if this were to be performed at a joining thickness of 1 μm, naturally, the flatness of the parts smaller than that would be required.
Therefore, there has been a problem that a member having poor flatness and a thin film bonding cannot be compatible.

The method of forming the escape groove for the adhesive as described above is also effective when there is a space for securing the escape groove. However, as described above, the integration degree of the ink jet head is high. Therefore, there is a problem that it is difficult to form a sufficient escape groove on the same plane.

Furthermore, as described above, the filling bonding method in which the joining gap between the two thin-layer members is first determined and the adhesive is poured into the joining gap by surface tension is used. This is effective when there are no parts, etc., and the surface is the same. However, if a fine flow path pattern is formed on the bonding surface like an inkjet head part or if there is a gap width distribution due to thickness variation, the bonding surface It is difficult to completely fill the adhesive with surface tension, there is a problem that an unattached area is likely to be generated partially, and the joining reliability is lowered.

In such an ink jet head having a partially unattached area, there are problems such as variations in ink droplet ejection characteristics and inability to eject ink, and an image in an ink jet recording apparatus equipped with such an ink jet head. There is also a problem that the quality is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and provides a droplet discharge head which reduces the amount of adhesive protruding and has high joining reliability, and a method of manufacturing the same. An object of the present invention is to provide an obtained ink jet recording apparatus.

[0014]

In order to solve the above-mentioned problems, a droplet discharge head according to the present invention has a wettability for improving the wettability of an adhesive on a joint surface side of at least one of two members. The structure is such that a property improving layer is formed, and the joining surface side of at least one of the two members has uneven thickness, and the thickness of the adhesive layer changes along the uneven thickness.

Here, the wettability improving layer is preferably an oxide film or a resin layer. When a resin layer is used, the main component is preferably polyimide.

In the droplet discharge head according to the present invention, a wettability improving process for improving the wettability of the adhesive is performed on a bonding surface side of at least one of the two members, and at least one of the two members is used. The joining surface side of one member has uneven thickness, and the thickness of the adhesive layer changes along the uneven thickness.

Here, the wettability improving treatment is preferably a plasma treatment or an ozone treatment.

In the droplet discharge head according to the present invention, it is preferable that the thickness deviation on the joining surface side of at least one of the two members is in the range of 2 to 15 μm.
Further, it is preferable that the thickness of the thinnest layer portion of the adhesive layer does not exceed 2 μm, and the total average film thickness does not exceed 5 μm. further,
A liquid chamber or a flow path can be formed by two members. Furthermore, the member with uneven thickness is preferably a nozzle plate on which a nozzle and / or a fluid resistance part is formed. In this case, the nozzle plate is preferably formed by a nickel electroforming method. Preferably, at least one of the two members is made of a silicon substrate, and a wettability improving layer is formed on the surface of the silicon substrate.

A method of manufacturing a droplet discharge head according to the present invention is a method of manufacturing a droplet discharge head according to the present invention, wherein an adhesive is applied to a joint surface of one of two members. By pressing the other member, the gap between the two members is filled with the adhesive, and the entire joining surface is joined.

Here, the adhesive is preferably a low-viscosity or liquid adhesive. In this case, the viscosity of the adhesive is 10
It is preferably in the range of 5000 cps. Further, it is preferable that the applied film thickness of the adhesive is smaller than the thickness deviation of the member. Further, it is preferable to apply an adhesive by a transfer method.

The ink jet recording apparatus according to the present invention comprises:
A droplet discharge head according to the present invention is mounted as an inkjet head for discharging ink droplets.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a schematic perspective explanatory view of a mechanism of an ink jet recording apparatus according to the present invention, and FIG. 2 is a side explanatory view of the mechanism.

This ink jet recording apparatus comprises a carriage movable in the main scanning direction inside the recording apparatus main body 1, a recording head including an ink jet head mounted on the carriage, an ink cartridge for supplying ink to the recording head, and the like. The paper feed cassette 4 or the manual feed tray 5 takes in the paper 3, and records the required image by the print mechanism 2, and then the output tray mounted on the rear side. 6 is discharged.

The printing mechanism 2 slides the carriage 13 in the main scanning direction (the direction perpendicular to the paper surface in FIG. 2) by a main guide rod 11 and a sub guide rod 12 which are guide members which are laterally mounted on left and right side plates (not shown). This carriage 1
In No. 3, a head 14 composed of an ink jet head which is a liquid droplet discharging head for discharging ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (Bk) is moved downward in the ink droplet discharging direction. Each ink tank (ink cartridge) 1 for supplying ink of each color to the head 14 is mounted above the carriage 13.
5 is exchangeably mounted.

Here, the carriage 13 is slidably fitted to the main guide rod 11 on the rear side (downstream side in the paper transport direction), and is slidably fitted on the front side (upstream side in the paper transport direction).
2 slidably mounted. The main scanning motor 1 is moved to scan the carriage 13 in the main scanning direction.
A timing belt 20 is stretched between a driving pulley 18 and a driven pulley 19, which are driven to rotate by 7, and the timing belt 20 is fixed to the carriage 13.

Although the recording heads 14 of the respective colors are used here, a single head having nozzles for ejecting ink droplets of the respective colors may be used. Furthermore, head 1
The ink jet head used as 4 is a piezo type which presses ink through a vibration plate forming a liquid chamber (ink flow path) wall with an electromechanical transducer such as a piezoelectric element, or a bubble generated by film boiling due to a heating resistor. A bubble type that pressurizes ink by generating it, or an electrostatic type that presses ink by displacing the diaphragm with electrostatic force between a diaphragm forming an ink flow path wall surface and an electrode facing the diaphragm However, in this embodiment, an electrostatic inkjet head is used as described later.

On the other hand, the paper 3 set in the paper feed cassette 4
Roller 21 and a friction pad 22 for separating and feeding the paper 3 from the paper feed cassette 4 and a guide member 23 for guiding the paper 3
A transport roller 24 that reverses and transports the fed paper 3, a transport roller 25 that is pressed against the peripheral surface of the transport roller 24, and a tip roller 26 that defines an angle at which the paper 3 is fed from the transport roller 24. Is provided. The transport roller 24 is driven to rotate by a sub-scanning motor 27 via a gear train.

An image receiving member 29 is provided as a paper guide member for guiding the paper 3 fed from the transport roller 24 below the recording head 14 in accordance with the moving range of the carriage 13 in the main scanning direction. I have. On the downstream side of the printing receiving member 29 in the sheet conveying direction, a conveying roller 31 and a spur 32, which are driven to rotate in order to send out the sheet 3 in the sheet discharging direction.
And a paper discharge roller 33 and a spur 34 for feeding the paper 3 to the paper discharge tray 6 and guide members 35 and 36 for forming a paper discharge path.

A reliability maintenance / recovery mechanism (hereinafter referred to as a "subsystem") 37 for maintaining and recovering the reliability of the head 14 is disposed on the right end side in the moving direction of the carriage 13. The carriage 13 is moved to the subsystem 37 side during printing standby, and the head 14 is capped by capping means or the like.

Next, an ink jet head constituting the head 14 of the ink jet recording apparatus will be described with reference to FIGS. 3 is an exploded perspective view of the head 14, FIG. 4 is a cross-sectional view of the head 14 in a direction orthogonal to the nozzle arrangement direction, FIG. 5 is an enlarged view of a main part of FIG. 4, and FIG. FIG. 7 is an enlarged plan view of a main part of the head 14 in a transparent state, in the nozzle arrangement direction.

An ink-jet head 40 serving as a droplet discharge head includes a single-crystal silicon substrate, a polycrystalline silicon substrate,
A flow path substrate (flow path forming member) 41 as a first member using a silicon substrate or the like such as an SOI substrate;
An electrode substrate 42 using a silicon substrate, a Pyrex (registered trademark) glass substrate, a ceramics substrate, or the like provided below, and a nozzle plate 43 as a second member provided above the flow path substrate 41. Nozzles for discharging the ink droplets, a pressurizing chamber 46 which is an ink flow path communicating with each nozzle 44, and a common liquid chamber flow communicating with each pressurizing chamber 46 via a fluid resistance portion 47 also serving as an ink supply path. A path 48 and the like are formed.

The flow path substrate 41 has a liquid chamber 46 and the liquid chamber 4.
6, a recess for forming a diaphragm 50 (which will be a first electrode) forming a bottom, which is a wall surface, is formed on the nozzle plate 43, a groove for forming a fluid resistance portion 47 is formed, and a flow path substrate 41 is formed. The electrode substrate 42 has a penetrating portion for forming the common liquid chamber flow path 48.

In this case, for example, when a single crystal silicon substrate is used as the flow path substrate 41, boron is injected in advance to the diaphragm thickness to form a high-concentration boron layer serving as an etching stop layer. After bonding, the concave portion serving as the liquid chamber 46 is anisotropically etched using an etching solution such as a KOH aqueous solution, whereby the high-concentration boron layer becomes an etching stop layer, and the diaphragm 50 is formed with high precision. You. When the diaphragm 50 is formed of a polycrystalline silicon substrate, a method of forming a polycrystalline silicon thin film serving as a diaphragm on a liquid chamber substrate, or a method in which the electrode substrate 42 is previously flattened with a sacrificial material, and After the polycrystalline silicon thin film is formed, it can be formed by removing the sacrificial material.

Although an electrode film may be separately formed on the diaphragm 50, the diaphragm also serves as an electrode by diffusion of impurities as described above. Further, the diaphragm 50
An insulating film can be formed on the surface on the electrode substrate 42 side. As this insulating film, an oxide-based insulating film such as SiO ₂
A nitride insulating film such as i ₃ N ₄ can be used.
For the formation of the insulating film, the surface of the diaphragm can be thermally oxidized to form an oxide film, or a film forming technique can be used.

An oxide film layer 42a is formed on the electrode substrate 42, a concave portion 54 is formed in the portion of the oxide film layer 42a, and an electrode 15 facing the diaphragm 50 is formed on the bottom surface of the concave portion 54.
(To be a second electrode), and the diaphragm 50 and the electrode 55
A gap 56 is formed between the vibration plate 50 and the electrode 55 to form an actuator section.
An electrode protection film 57 made of an oxide-based insulating film such as a SiO ₂ film or a nitride-based insulating film such as a Si ₃ N ₄ film is formed on the surface of the electrode 55. Membrane 5
An insulating film can be formed on the diaphragm 50 side without forming the layer 7.

When a single crystal silicon substrate is used as the electrode substrate 42, a normal silicon wafer can be used. The thickness varies depending on the diameter of the silicon wafer, but in the case of a 4-inch diameter silicon wafer, the thickness is about 500 μm, and in the case of a 6-inch diameter silicon wafer, the thickness is often about 600 μm. When a material other than the silicon wafer is selected, the smaller the difference in thermal expansion coefficient from silicon of the flow path substrate, the more the reliability can be improved when bonding to the diaphragm. For example, as the glass material, # 7740 (trade name) manufactured by Corning Incorporated, SW3 (trade name) manufactured by Iwaki Glass Co., Ltd., SD2 (trade name) manufactured by Hoya Corporation, and the like can be used.

The bonding between the flow path substrate 41 and the electrode substrate 42 can be performed by an adhesive, but a more reliable physical bonding, for example, when the electrode substrate 42 is formed of silicon, A direct bonding method via an oxide film can be used. This direct bonding is performed at a high temperature of about 1000 ° C. When the electrode substrate 42 is made of glass, anodic bonding can be performed. When the electrode substrate 42 is formed of silicon and anodic bonding is performed, Pyrex glass may be formed between the electrode substrate 42 and the flow path substrate 41, and anodic bonding may be performed via this film. Furthermore, the flow path substrate 41 and the electrode substrate 42 can be bonded by eutectic bonding in which a binder such as gold is interposed between bonding surfaces using a silicon substrate.

The electrodes 55 of the electrode substrate 42 include:
A commonly used in the process of forming a semiconductor element
Metal materials such as l, Cr, and Ni, high melting point metals such as Ti, TiN, and W, and polycrystalline silicon materials whose resistance has been reduced by impurities can be used. When the electrode substrate 42 is formed of a silicon wafer, it is necessary to form an insulating layer (the above-described oxide film layer 42a) between the electrode substrate 42 and the electrode 55. When an insulating material such as a glass substrate or a ceramic substrate is used for the electrode substrate 42, it is not necessary to form an insulating layer between the electrode substrate 42 and the electrode 55.

When a silicon substrate is used as the electrode substrate 42, an impurity diffusion region can be used as the electrode 55. In this case, an impurity used for diffusion is an impurity having a conductivity type opposite to the conductivity type of the substrate silicon, a pn junction is formed around the diffusion region, and the electrode 55 and the electrode substrate 42 are formed.
Are electrically insulated from each other.

The nozzle plate 43 has a large number of nozzles 44 and a groove for forming a fluid resistance portion 47 for communicating the common liquid chamber flow path 47 with the liquid chamber 46. Here, the nozzle plate 43 is manufactured by the Ni electroforming method, but in addition, for example, SUS, or a multi-layer structure of a resin and a metal layer can be used. The nozzle plate 43 is joined to the flow path substrate 41 by an adhesive layer 105 described later.

In this case, the wettability improving layer 4 for improving the wettability of the adhesive is provided on the joint surface of the flow path substrate 41 with the nozzle plate 43.
9 are formed. Note that the wettability improving layer 49 is provided instead of the flow channel substrate 41 or together with the flow channel substrate 41.
It can also be provided on the side.

Various materials such as organic and inorganic can be used as the wettability improving layer 49. However, since a silicon substrate is used as the flow channel substrate 41, a silicon oxide film is provided on the flow channel substrate 41 side. It is preferable to form with.
By using the silicon oxide film as the wettability improving layer 49, the liquid chamber 46 of the flow path substrate 41 and the diaphragm 5
It can be formed consistently in the step of forming 0 and the like, and the number of steps is not greatly increased.

When the wettability improving layer 49 is formed of an organic layer, it is effective to use a resin layer formed by resin coating. For forming the resin coating layer, a thin layer can be formed by diverting an adhesive coating method described below as it is. In particular, by using a polyimide resin coat layer as the resin layer, when a silicon substrate is used for the flow path substrate 41 or the like, the bonding strength with silicon is high, and this is extremely effective in improving the bonding strength.

In order to align the liquid chamber between the nozzle plate 43 and the flow path substrate 41, an ultraviolet-curing adhesive or an instant adhesive for temporary bonding is applied to the corners of the flow path substrate 41 for temporary bonding. After that, the adhesive for the final bonding is cured by heating. As the adhesive for the main bonding, warpage occurs due to a difference in linear expansion coefficient between a flow path substrate using a silicon substrate and a nozzle plate using Ni, SUS, or the like at the time of heat bonding. The curing temperature of the adhesive is preferably low, and the temperature is preferably from room temperature to 100 ° C., since the actuator may be broken. Further, a two-component mixed type (room temperature curing type) epoxy adhesive is also suitable for use.

In the ink jet head 40, the nozzles 44 are arranged in two rows, and the liquid chambers 4 correspond to the respective nozzles 44.
6, the diaphragm 50, the electrodes 55, etc. are also arranged in two rows, a common liquid chamber flow path 48 is arranged at the center of each nozzle row, and ink is supplied to the left and right liquid chambers 46. This makes it possible to configure a multi-nozzle head having a large number of nozzles with a simple head configuration.

The electrode 55 of the ink-jet head 40 is extended outside to form a connection portion (electrode pad portion) 55a, and an FPC cable 61 having a driver IC 60 as a head drive circuit mounted thereon by wire bonding is anisotropically connected. They are connected via a conductive film or the like. At this time, the gap between the electrode substrate 42 and the nozzle plate 43 (the entrance of the gap 56) is hermetically sealed with a gap sealing agent 62 using an adhesive such as an epoxy resin as shown in FIG. This prevents the diaphragm 50 from being displaced due to the invasion of moisture.

Further, the entire ink jet head 40 is joined onto the frame member 65 with an adhesive. The frame member 65 has an ink supply hole 66 for supplying ink from outside to the common liquid chamber flow path 48 of the inkjet head 40, and the FPC cable 61 and the like have holes 67 formed in the frame member 65. Is stored in.

The gap between the frame member 65 and the nozzle plate 43 is sealed with a gap sealing agent 68 using an adhesive such as an epoxy resin as shown in FIG. The ink is applied to the electrode substrate 42 and the FPC cable 6
It is prevented from going around to 1st mag.

The frame member 6 of the head 14
5 includes a joint member 70 with the ink cartridge 15.
Are connected to each other, and ink is supplied from the ink cartridge 15 to the common liquid chamber flow path 48 through the ink supply hole 66 through the filter 71 thermally fused to the frame member 65.

In the ink jet head 40, the diaphragm 50 and the electrode 55 are connected to each other by applying a driving voltage between the diaphragm 50 and the electrode 55 by using the diaphragm 50 as a common electrode and the electrode 55 as an individual electrode. The diaphragm 50 is deformed and displaced toward the electrode 55 due to the electrostatic force generated during the period, and from this state, the electric charge between the diaphragm 50 and the electrode 55 is discharged, whereby the diaphragm 50 is returned and deformed, and the liquid chamber 4
When the internal volume (volume) / pressure of 6 changes, ink droplets are ejected from the nozzles 44.

That is, when a pulse voltage is applied to the electrode 55 serving as an individual electrode, a potential difference occurs between the electrode 55 and the diaphragm 50 serving as a common electrode, and an electrostatic force is generated between the individual electrode 55 and the diaphragm 50. As a result, the diaphragm 50 is displaced according to the magnitude of the applied voltage. After that, the applied pulse voltage is dropped, the displacement of the diaphragm 50 is restored, and the restoring force increases the pressure in the liquid chamber 46, and the nozzle 4
4 ejects ink droplets. In this case, a method in which the diaphragm 50 is displaced until it comes into contact with the electrode 55 (actually, the surface of the insulating protective film 57) is a contact driving method, and the diaphragm 50 is
The method of displacing to a position where it is not brought into contact with 5 is referred to as a non-contact driving method.

The details of the joining between the flow path substrate 41 and the nozzle plate 43 in the ink jet head in this ink jet recording apparatus will be described with reference to FIGS. In the following description, the fluid resistance part 47 is defined by the groove of the nozzle plate 43 and the flow path substrate 41, but for convenience, the groove of the nozzle plate 43 is referred to as the fluid resistance part 47.

First, an example of a manufacturing process when the nozzle plate 43 is manufactured by electroforming will be described with reference to FIG. First, as shown in FIG. 1A, an electroformed supporting substrate 81 formed by forming a conductive film on a glass substrate surface or a conductive substrate or the like is used.
After forming a first layer dry film resist (or thick film resist) 82 thereon, pattern exposure is performed to expose an exposure portion 83 to a portion corresponding to the fluid resistance portion 47 as shown in FIG. Form.

Next, as shown in FIG. 5C, the second layer dry film resist (or thick film resist) 84 is formed.
After the film is formed, pattern exposure is performed to form the first and second dry film resists 8 as shown in FIG.
Exposure portions 85 are formed at portions corresponding to the nozzle holes 44 through the holes 2 and 84. Thereafter, as shown in FIG. 9E, development is performed to remove unexposed portions, leaving exposed portions 83 and 85.

Then, Ni electroforming is performed to form an electroformed plating film 86 on the electroformed support substrate 81 as shown in FIG. By peeling and removing the exposed portions 83 and 85, a nozzle plate 43 having a nozzle hole 44 and a fluid resistance portion 47 is obtained as shown in FIG.

Next, another example of the manufacturing process when the nozzle plate 43 is manufactured by electroforming will be described with reference to FIG.
First, as shown in FIG. 1A, an electroformed support substrate 9 having a conductive film formed on a glass substrate surface or a conductive substrate or the like is used.
After forming a resist pattern 92 on the position 1 corresponding to the nozzle hole 44, as shown in FIG. 2B, Ni electroforming is performed to form an electroformed plating film 93.

Next, as shown in FIG. 3C, a dry film resist (or a thick film resist) is formed on the electroformed plating film 93 at a position corresponding to the nozzle hole 44 and a position corresponding to the fluid resistance portion 47. After the patterns 94 and 95 are formed, Ni electroforming is performed again, a plating film is superimposed on the electroformed plating film 93, and as shown in FIG.
An electroformed plating film 96 having a thickness of 3 is formed.

Then, as shown in FIG. 6E, after the resist pattern is peeled off from the electroformed support substrate 91, the resist patterns 92 and 9 are removed.
4 and 95, the nozzle plate 43 having the nozzle hole 44 and the fluid resistance portion 47 is obtained as shown in FIG.

Next, the flow path substrate 41 as the first member and the second
FIG. 10 shows adhesive bonding with nozzle plate 43 as a member.
This will be described with reference to FIG. FIG. 3 is a schematic explanatory view illustrating the head 14 in an enlarged manner.

The nozzle plate 43 is bonded to the wettability improving layer 49 of the flow path substrate 41 by the adhesive layer 105. When viewed in the thickness direction, the nozzle plate 43 is bonded to the flow path substrate 41 at the bonding surface. Thus, the fluid resistance portion 47 is thicker and the nozzle hole 44 is thinner in cross section, so that it has a shape having an uneven thickness that becomes an inclined surface. Accordingly, a gap formed between the joining surface of the nozzle plate 43 and the joining surface of the flow path substrate 41 has a cross-sectional shape that gradually increases from the vicinity of the fluid resistance portion 47 toward the nozzle hole 44 in the thickness direction. Make In addition, according to the actual measurement, the thickness deviation of about 3 μm was confirmed with respect to the nozzle plate 43 having a thickness of 50 μm.

This uneven thickness of the nozzle plate 43 occurs, for example, when the nozzle plate 43 is manufactured by the electroforming method because the current density distribution differs depending on the part, and is manufactured by the method shown in FIG. 8 or FIG. , Shielding during electroforming (resist)
As the proportion of the area increases, the current density in the vicinity of the shield increases, and the thickness of the electroformed plating film tends to increase. Therefore, in this method, the fluid resistance portion 47 having the larger shielding area has the largest thickness. When the adhesive bonding is performed in this state, the crushing of the adhesive in the fluid resistance portion having a thick electroformed film thickness increases, and the amount of the protrusion increases. The overflow causes a change in the fluid resistance value, causing variations in the droplet discharge characteristics or incapability of discharging.

Therefore, in the present invention, a thin film filling head utilizing the uneven thickness generated in the nozzle plate 43 is manufactured to manufacture a droplet discharge head with less variation in the ejection characteristics. In this case, the present invention is not limited to nickel electroforming, and may be similarly applied to a nozzle plate or the like that can be manufactured by a method capable of causing uneven thickness.

Here, the step of joining the nozzle plate 43 and the flow path substrate 41 will be described with reference to FIG. FIG. 3 is a schematic explanatory view schematically illustrating the nozzle plate 43 and the flow path substrate 41 by omitting a portion of a liquid chamber.

First, an adhesive 101 is applied to the upper surface of the flow path substrate 41 as shown in FIG. Various methods such as a spin coating method, a spraying method, and a transfer method can be applied to this coating method. Among these coating methods, the transfer method is a method in which a fine pattern is formed on a bonding surface like the flow path substrate 41. There is an adhesive 10 only on the upper surface of the convex portion which is the actual bonding surface.
1 is most excellent in that a thin layer is formed.

This transfer method will be described with reference to FIG. 12. The adhesive 101 is dropped on a rotating developing roll 111 and spread using a doctor blade 112 to form a thin layer.
The thinned adhesive on the developing roller 111 is transferred to a resin relief 114 having fine irregularities on the surface provided on the rotating application roll 113. At this time, the resin letterpress 114
The adhesive 101 is held on the upper unevenness.

Then, the flow path substrate 41 as a member to be coated is placed on the stage 115 and moved in the direction of the arrow, and the resin relief 114 on the coating roll 113 is rotated to make the resin relief 114 uneven. By re-transferring the held adhesive 101 onto the flow path substrate 41, a thin layer of the adhesive 101 of about 1 μm is formed on the joint surface of the flow path substrate 41.

Returning to FIG. 11A, the thickness (applied thickness) b of the adhesive 101 applied to the convex portion (joining surface) of the flow path substrate 41 is equal to or less than the thickness deviation a of the nozzle plate 43 ( a ≧ b). If the coating thickness b is equal to or more than the uneven thickness a, the joining is completely performed, but the thick portion (the fluid resistance portion 47) of the nozzle plate 43 is formed.
In the vicinity, most of the adhesive runs out, closes the fluid resistance portion 47, and causes variation in ejection characteristics or non-ejection. The coating thickness b of the adhesive 101 varies depending on the distribution of uneven thickness or the like.
It is preferred to be about 2.

Next, as shown in FIG. 6B, when the nozzle plate 43 is pressed against the flow path substrate 41 on which the adhesive 101 is applied, the nozzle plate 4
An unjoined region is formed in a gap between the channel substrate 3 and the flow path substrate 41.

By keeping the viscosity of the adhesive 101 low at this time, as shown in FIG.
Is moved by a capillary phenomenon into a gap 104 formed between the flow path substrate 41 and the nozzle plate 43 and filled therein. As shown in FIG. Are bonded over the entire bonding surface with an adhesive 101.
In this manner, bonding is performed with an adhesive applied film thickness smaller than the thickness deviation of the nozzle plate 43. Therefore, the thickness of the adhesive layer 105 at the bonding surface at this time varies along the thickness deviation of the nozzle plate 43.

Here, the viscosity of the adhesive 101 is affected by the wettability with the material, but is preferably 5000 cps or less. If it exceeds 5,000 cps, the filling property of the adhesive due to the capillary phenomenon becomes poor, the voids cannot be sufficiently filled, and it becomes difficult to maintain the bonding. The value of the viscosity at this time is the viscosity at the time of joining, and when a heating step is added at the time of joining, it is necessary to consider the change in viscosity in the temperature increasing step.

In this case, the bonding between the flow path substrate 41 and the nozzle plate 43 is not performed by the adhesive 101 extruded by simple pressurization by pressing the nozzle plate 43. This means that the thickness c of the adhesive layer 105 on the non-bonded surface (thickness of the adhesive-coated non-bonded portion) c is smaller than the initial applied film thickness b of the adhesive 101, as shown in part A of FIG. Is confirmed.

More specifically, it was confirmed that the adhesive 101 applied at a thickness of 1 μm had a thickness of about 0.2 μm at the non-joined portion. This indicates that the adhesive 101 has moved due to the capillary phenomenon. Although the fluid resistance portion is shown here, it has been confirmed that when such a thinned portion is formed in the thin portion of the nozzle plate 43, the movement of the adhesive appears more remarkably.

Here, the relationship between the viscosity of the adhesive and the thickness variation a of the members to be joined will be described. According to the experiment of the inventor, when the wettability improving layer 49 is not formed on the bonding surface,
When the viscosity of the adhesive is 100 cps or more, the uneven thickness a is 2
If it is in the range of 10 to 10 μm, the filling by the capillary force of the adhesive was performed well, but if the uneven thickness a exceeds 10 μm,
If the adhesive is not filled by the capillary force, and if the thickness deviation a is less than 2 μm, the effect that the gap (void) formed by the thickness deviation becomes the escape portion of the adhesive cannot be expected, and the protrusion increases. It turned out to be.

In this case, the poor filling can be solved by using an adhesive having a lower viscosity. However, the lowering of the viscosity of the adhesive is caused by uneven coating due to uneven wettability of the coating surface (joining surface). Cause Actually, it has been confirmed that when an adhesive having a viscosity of about 70 cps is applied to the Si surface, the adhesive is repelled on the Si surface, becomes a droplet, and is distributed on the surface.

Thus, the inventor repeated experiments and found that
By forming the wettability improving layer 49 on one or both of the bonding surfaces, it has been found that the coating can be performed uniformly.
According to the experiment, by providing the wettability improving layer 49,
Even a low-viscosity adhesive having a viscosity of up to about 10 cps can be uniformly applied to the bonding surface. If the thickness of the adhesive is a of up to about 15 μm due to the low viscosity of the adhesive, good filling bonding can be achieved. It is now possible to do.

Further, it is preferable that the applied thickness b of the adhesive is the minimum necessary for reducing the protrusion, and the adhesive layer in the joined state is 2 μm or less in the thinnest layer portion.
It is preferable that the average film thickness does not exceed 5 μm. FIG.
(A) shows an example in which the adhesive 101 is applied with a coating film thickness exceeding the thickness deviation of the nozzle plate 43. In this case, the bonding is completely performed, but FIG. As shown, most of the adhesive 101 protrudes in the vicinity of the fluid resistance portion 47 which is the non-applied portion of the adhesive, and the thickness of that portion becomes larger than the thickness deviation a, and the fluid resistance portion 47 is closed.
It has been confirmed that the injection characteristics vary and the injection becomes impossible.

As described above, since at least one of the two members to be bonded with the adhesive has a thickness variation and the adhesive layer changes in accordance with the thickness variation, the initial coating thickness of the adhesive is reduced. The adhesive which can be made thin and which is to be protruded moves to the gap between the two members by capillary action, so that the amount of the adhesive which protrudes into the recesses and the like is remarkably reduced, and the adhesive is spread over the entire joint surface. Joining is possible, and joining reliability is also improved.

In particular, in the case of a joining member in which a liquid chamber substrate having a fine concavo-convex pattern, such as a droplet discharge head, and a nozzle plate or a lid member are joined, the adhesive is not applied to the fluid resistance portion where the adhesive is not protruded. Since the protrusion is remarkably reduced and the entire bonding surface can be bonded, variations in the droplet discharge characteristics are reduced, and problems such as defective discharge do not occur.

By providing a wettability improving layer,
It is possible to reduce the viscosity of the adhesive that can be used, and the above-mentioned capillary phenomenon is conspicuous, and a large void due to uneven thickness of 10 μm or more can be filled.

Further, the present inventor repeated experiments and found that
Even if the wettability improving layer is not provided, the same operation and effect as provided by the wettability improving layer can be obtained by performing the process of improving the wettability of the adhesive on the bonding surface (wetability improving process). I found it. As the wettability improving treatment, a plasma treatment or an ozone treatment can be performed.

The wettability improving treatment removes fine dust and dirt adhering to the surface of the joint surface, cleans the surface of the joint surface relatively easily and more reliably than using a wet cleaning agent, and increases the wettability. Can be improved. Specifically, the plasma treatment can be performed by placing a member having a bonding surface that improves wettability in plasma,
Fine dust and dirt attached to the member surface are decomposed and removed by ion bombardment and chemical etching.

The ozone treatment can be performed by exposing a member having a bonding surface for improving wettability to UV light in an ozone atmosphere, whereby fine dust and dirt adhering to the member surface are removed. Decomposed and removed by chemical actions such as oxidation.

In order to further improve the wettability of the bonding surface, a plurality of techniques can be used in combination, such as using the above-mentioned resin coating and plasma treatment together.

As described above, by adopting the thin film coating + filling bonding method, even a member having a fine pattern with a certain thickness can be bonded uniformly over the entire surface, and bonding with a small amount of protrusion can be performed. . In addition, by providing a wettability improving layer on the joint surface or performing a wettability improving treatment, an adhesive having a lower viscosity can be used, and this effect can be further exerted. Of course, the member to be joined is not limited to the nozzle plate (nozzle plate), and can be applied to any member that requires joining accuracy that does not want the adhesive to protrude.

Therefore, in the ink jet recording apparatus equipped with the above-described droplet discharge head,
Even if the density is increased, the image is not disturbed or lost due to variations in droplet discharge characteristics or droplet discharge failure, and image quality is significantly improved.

In each of the above embodiments, the plane shape of the diaphragm and the electrodes of the electrostatic ink jet head has been described as rectangular, but the plane shape may be trapezoidal or triangular. Further, in each of the above-described embodiments, the vibration plate and the liquid chamber are formed of the same member as the flow path substrate in the ink jet head. However, the vibration plate and the liquid chamber forming member may be formed of different members and joined. .

In the droplet discharge head to which the present invention is applied, the shape, arrangement, and forming method of the nozzles, liquid chambers, fluid resistance portions, and common flow path liquid chambers formed in the flow path substrate can be appropriately changed. it can. For example, in the above embodiment, the nozzle is a side shooter type head formed so that ink droplets are ejected in the direction of displacement of the diaphragm, but the nozzle ejects ink droplets in a direction intersecting the direction of displacement of the diaphragm. An edge shooter type head formed so as to perform the above-described operation may be used.

Further, in each of the above embodiments, an example is described in which the droplet discharge head is an electrostatic ink jet head, but a piezo ink jet head using a piezoelectric element or a bubble using a heating resistor is used. The present invention can also be applied to other types of inkjet such as a type inkjet head. The droplet discharge head is not limited to one that discharges ink droplets, and can be applied to one that discharges droplets of liquid resist or the like.

[0089]

As described above, according to the droplet discharge head of the present invention, the wettability improving layer for improving the wettability of the adhesive is provided on the bonding surface side of at least one of the two members. It is formed, and the joining surface side of at least one of the two members has uneven thickness, and the thickness of the adhesive layer is changed along the uneven thickness, so that the amount of the adhesive protruding is reduced. In addition, it is possible to reduce the variation in the discharge characteristics, to achieve good bonding regardless of the bonding surface accuracy and material, to improve bonding reliability, and to perform bonding using a lower viscosity adhesive. Can be.

Here, by forming an oxide film as the wettability improving layer, it becomes easy to form the wettability improving layer when a silicon substrate is used as a flow path forming member for forming a liquid chamber or the like. Further, by forming the resin layer as the wettability improving layer, the wettability improving layer can be easily formed in the same process as the adhesive layer. In addition, by using a resin layer made of polyimide as a main component as a wettability improving tank, ink resistance is improved, and bonding with a strong bonding force can be performed.

According to the droplet discharge head of the present invention, 2
At least one member of the two members is subjected to a wettability improving treatment for improving the wettability of the adhesive on the joining surface side of the member, and 2
The joining surface side of at least one of the two members has uneven thickness, and the thickness of the adhesive layer changes along the uneven thickness, so that the amount of the adhesive protruding is reduced, and variations in the discharge characteristics are caused. Reduces the accuracy of joining surfaces and materials,
Good bonding can be performed, bonding reliability can be improved, and bonding using a lower-viscosity adhesive can be performed.

Here, as the wettability improving treatment, the plasma treatment or the ozone treatment can be performed relatively easily and surely to improve the wettability of the bonding surface.

In the droplet discharge head according to the present invention, by ensuring that the thickness deviation on the joining surface side of at least one of the two members is within the range of 2 to 15 μm, It is possible to suppress the protrusion of the adhesive and completely bond the entire bonding surface. The thickness of the adhesive layer does not exceed 2 μm and the overall average film thickness does not exceed 5 μm, so that the amount of the adhesive material can be reduced and the amount of protrusion can be further suppressed.

Further, by forming the liquid chamber or the flow path with two members, it is possible to suppress the protrusion to the fluid resistance portion, which requires the highest accuracy. Furthermore, the uneven thickness member can be easily formed by forming a nozzle plate having a nozzle and / or a fluid resistance portion formed thereon, and can protrude regardless of the surface accuracy and material of the nozzle plate. Bonding with reduced nozzle blockage can be achieved. In this case, since the nozzle plate is formed by the nickel electroforming method, it is possible to form a nozzle having a high nozzle diameter and a high precision in shape, and it is possible to perform full-surface joining by suppressing thin-layer joining.

Further, at least one of the two members is made of a silicon substrate, and a wettability improving layer is formed on the surface of the silicon substrate or subjected to a wettability improving process, so that the wettability improving layer is uniformly formed. It can be formed or the surface properties of the bonding surface can be enhanced.

According to the method of manufacturing a droplet discharge head according to the present invention, there is provided a method of manufacturing a droplet discharge head according to the present invention, wherein an adhesive is applied to a joint surface of one of two members. By applying and pressing the other member, 2
Adhesive is filled in the gap between the two members, and the entire joining surface is joined. Therefore, using a low-viscosity adhesive, the members on which the fine pattern is formed are entirely joined while suppressing the protrusion of the adhesive. As a result, it is possible to obtain a droplet discharge head with less variation in discharge characteristics.

Here, when the adhesive is a low-viscosity or liquid adhesive, filling and joining becomes easy. In this case, since the viscosity of the adhesive is in the range of 10 to 5000 cps, uniform application is possible, and the adhesive moves to the void portion by the capillary phenomenon only when pressed at the time of joining, and the filling joining is possible. Becomes In addition, since the applied film thickness of the adhesive is smaller than the uneven thickness of the member, the surplus adhesive flows into the voids by the capillary phenomenon, so that bonding with less protrusion can be performed reliably. Further, by applying the adhesive by a transfer method, the adhesive can be easily applied only to a necessary portion even in a member on which a fine pattern is formed, and the adhesive application of several thousand cps, which is difficult by the spin coating method, is extremely performed. It can be done easily.

According to the ink jet recording apparatus of the present invention, since the ink jet head for jetting the ink droplets is equipped with the ink jet head of the present invention, the ink jetting characteristics are less varied and the image quality is improved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective explanatory view of a mechanism section of an ink jet recording apparatus according to the present invention.

FIG. 2 is an explanatory side view of the mechanism.

FIG. 3 is an exploded perspective view of a head of the recording apparatus.

FIG. 4 is an explanatory cross-sectional view of the head in the longitudinal direction of the diaphragm.

FIG. 5 is an enlarged explanatory view of a main part of FIG. 4;

FIG. 6 is an explanatory cross-sectional view of the head in a lateral direction of the diaphragm.

FIG. 7 is an explanatory plan view of a main part of the head.

FIG. 8 is an explanatory view illustrating an example of a manufacturing process of a nozzle plate.

FIG. 9 is an explanatory view illustrating another example of the manufacturing process of the nozzle plate.

FIG. 10 is a schematic explanatory view for explaining a joined state between a flow path substrate and a nozzle plate.

FIG. 11 is a schematic explanatory view for explaining a joining step of a flow path substrate and a nozzle plate.

FIG. 12 is an explanatory view illustrating a method of applying an adhesive to a flow path substrate.

FIG. 13 is an explanatory diagram illustrating a comparative example of the amount of adhesive applied to a flow path substrate.

[Explanation of symbols]

13: carriage, 14: head, 24: transport roller,
33: paper ejection roller, 40: ink jet head, 41
... channel substrate, 42 ... electrode substrate, 43 ... nozzle plate, 44 ...
Nozzle, 46: liquid chamber, 47: fluid resistance part, 48: common flow path liquid chamber, 49: wettability improving layer, 50: diaphragm, 55: electrode, 101: adhesive, 104: gap, 105: adhesive layer .

Claims (18)

[Claims] A nozzle for discharging liquid droplets, a liquid chamber communicating with the nozzle, and pressure generating means for generating a pressure for pressurizing the liquid in the liquid chamber. In a droplet discharge head having a member, a wettability improving layer for improving the wettability of an adhesive is formed on a bonding surface side of at least one of the two members, and at least one of the two members. The joining surface side of the member has uneven thickness, and the thickness of the adhesive layer changes along the uneven thickness. 2. The droplet discharge head according to claim 1, wherein the wettability improving layer is an oxide film. 3. The droplet discharge head according to claim 1, wherein the wettability improving layer is a resin layer. 4. The droplet discharge head according to claim 3, wherein a main component of the resin layer is polyimide. 5. A nozzle for discharging droplets, a liquid chamber communicating with the nozzle, and pressure generating means for generating a pressure for pressurizing the liquid in the liquid chamber. In a droplet discharge head having a member, a wettability improving process for improving a wettability of an adhesive is performed on a bonding surface side of at least one of the two members, and at least one of the two members. The joining surface side of the member has uneven thickness, and the thickness of the adhesive layer changes along the uneven thickness. 6. The droplet discharge head according to claim 5, wherein the wettability improving treatment is a plasma treatment or an ozone treatment of a bonding surface. 7. The droplet discharge head according to claim 1, wherein the thickness deviation on the joining surface side of at least one of the two members is in a range of 2 to 15 μm. Characteristic droplet discharge head. 8. The droplet discharge head according to claim 1, wherein the thickness of the adhesive layer is 2
A droplet discharge head, wherein the total average film thickness does not exceed 5 μm. 9. The droplet discharge head according to claim 1, wherein a liquid chamber or a flow path is formed by said two members. 10. The droplet discharge head according to claim 1, wherein the uneven member is a nozzle plate having a nozzle and / or a fluid resistance portion. Discharge head. 11. The droplet discharge head according to claim 10, wherein the nozzle plate is formed by a nickel electroforming method. 12. The droplet discharge head according to claim 1, wherein at least one of the two members is made of a silicon substrate. 13. The method for manufacturing a droplet discharge head according to claim 1, wherein an adhesive is applied to a joining surface of one of the two members, and A method for manufacturing a droplet discharge head, wherein a gap between the two members is filled with the adhesive by pressing the members, and the entire bonding surface is bonded. 14. The method for manufacturing a droplet discharge head according to claim 13, wherein the adhesive is a low-viscosity or liquid adhesive. 15. The method of manufacturing a droplet discharge head according to claim 14, wherein the viscosity of the adhesive is 10 to 5000.
A method for manufacturing a droplet discharge head, which is within the range of cps. 16. The method of manufacturing a droplet discharge head according to claim 13, wherein a coating thickness of the adhesive is smaller than an uneven thickness of the member. A method for manufacturing a discharge head. 17. The method for manufacturing a droplet discharge head according to claim 13, wherein the adhesive is applied by a transfer method. 18. An ink jet recording apparatus equipped with an ink jet head for discharging ink droplets, wherein the ink jet head is the liquid drop discharge head according to any one of claims 1 to 10. .