JP2007331346A - Nozzle plate and method for manufacturing nozzle plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nozzle plate which maintain the stable meniscus on an opening part of a discharge side of a nozzle and which has a structure of excellent adhesive strength and adhesion of a metal plate body, resin sheet and water repellent film and which can be manufactured by a simple process, and to provide a method for manufacturing the same. <P>SOLUTION: The nozzle plate for an ink jet head is obtained by laminating a sheet having the water repellent film in a surface of a base layer comprising a hydrophilic polymer material in a discharge side of a hydrophilic metal plate body 1 having a through-hole, which previously become a nozzle, using the water repellent film 3 as an outside face, and forming the nozzle by opening the part corresponding to the through-hole of the metal plate body of the sheet having the water repellent film. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ink jet head nozzle plate and a method of manufacturing the same.

  In recent years, inkjet printers are widely used as on-demand printing methods. As a method, a bubble jet method in which ink in a flow path is heated and fired by a heater and droplets are ejected from a nozzle, and a piezoelectric element fixed to a diaphragm is used to displace ink in a flow path and droplets are ejected from a nozzle. Piezo method is common.

  In order to eject droplets more stably and straightly, it is of course essential to optimize the design in the flow path and the method of applying pressure to the ink. However, this is not sufficient, and it is necessary to always maintain a stable surface around the nozzles that eject ink. For this purpose, it is necessary to provide water repellency so that ink does not adhere to and remain on the periphery of the nozzle opening on the ink ejection surface. As a specific method for imparting water repellency, application of a silicon-based or fluorine-based resin to a predetermined portion of the ink discharge surface or tephron eutectoid plating is widely known.

  As a method for forming the water repellent film, a spin coating method or a dipping method using a fluorine-based resin is employed. In this case, for example, a method is known in which a fluorine-based resin is applied with a film thickness of 1 μm or less on a resin substrate such as polyimide having a film thickness of 50 μm or more, and after drying, a nozzle is formed by laser irradiation. . Further, in Teflon eutectoid plating, a nickel plate substrate is used as a base, and after a through-hole serving as a nozzle is previously formed in this substrate, Teflon eutectoid plating is performed on the discharge side surface. At that time, a mask process or the like is required so that Teflon eutectoid plating does not deposit in the nozzle.

  The method of forming a nozzle by laser irradiation after applying a water repellent film to the polyimide substrate described above has a large amount of removal by laser irradiation. There are cases where problems such as distortion occur. For this reason, the straightness of droplet ejection tends to be hindered. In addition, when a Teflon eutectoid plating is formed by performing a mask process on a Ni substrate on which a nozzle has been previously formed, the process itself becomes very complicated, and the resist used in the mask process is completely removed from within the nozzle. Problems such as being very difficult to occur may occur.

As a method of solving the above problem, a water-repellent resin sheet is bonded to a metal plate substrate in which a through-hole serving as a nozzle is previously formed, and a hole is formed by laser irradiation or the like at a position corresponding to the nozzle discharge port of the resin sheet. A method has been proposed (Japanese Patent Laid-Open No. 10-305584). In this patent document, the boundary position between the water repellency and the hydrophilicity in the ink discharge hole is uniform, and the meniscus position can be made constant.
Japanese Patent Laid-Open No. 10-305584

  In the above-described method in which the water-repellent resin sheet is bonded to the metal plate substrate and then the holes are formed in the resin sheet, the resin sheet has water repellency, so it is good when the resin sheet is bonded to the metal plate substrate with an adhesive. May not provide good adhesion and adhesive strength. Adhesion of these members is necessary not only for adhesion of the metal plate substrate and the water-repellent resin sheet but also for maintaining the sealing performance against the ink around the nozzle. In other words, if there is poor adhesion at the boundary between the metal plate base and the water-repellent resin sheet in the nozzle, there is a possibility that problems such as enlargement of the poor adhesion due to the penetration of ink into this part and occurrence of ink leakage may occur. Get higher.

  On the other hand, the meniscus position when incorporated in the head in the nozzle in the configuration in which the water-repellent resin sheet is laminated on the hydrophilic metal plate substrate is usually deeper by the thickness of the resin sheet than the opening on the discharge side. It will be a place that has been withdrawn. However, in this configuration, in order to stably maintain the meniscus at the above position, there may be a restriction that the pressure of the ink in the head must be controlled to an appropriate negative pressure. Furthermore, if continuous discharge is performed, the meniscus position may not be stable, and the metal plate base and the resin sheet may move to the discharge side. This is because the water repellency of the water-repellent resin sheet on the processed surface gradually changes while ink contact and passage through the resin sheet in the nozzle are repeated during ink ejection. As described above, when the meniscus position becomes unstable, the problem is that the original discharge performance cannot be maintained, and when a plurality of nozzles are provided, the discharge performance varies among the nozzles. It becomes.

  An object of the present invention is to provide a structure that can stably maintain a meniscus in a discharge side opening of a nozzle, and has a structure in which a metal plate substrate, a resin sheet, and a water-repellent film have good adhesive strength and adhesion. It is in providing the nozzle plate which can be manufactured by, and its manufacturing method.

A method of manufacturing a nozzle plate for an inkjet head according to the present invention is as follows.
A sheet having a water-repellent film on the surface of a base layer made of a hydrophilic polymer material is laminated on the surface of the liquid discharge side where a through-hole serving as a nozzle of a hydrophilic metal plate substrate opens, with the water-repellent film as an outer surface. And a process of
Opening a portion corresponding to the opening of the through hole of the sheet to open the nozzle;
It is a manufacturing method of the nozzle plate characterized by having.

  One aspect of the nozzle plate of the present invention is obtained by the manufacturing method described above.

  In another aspect of the nozzle plate of the present invention, in the nozzle plate for an ink jet head, a sheet having a base layer made of a hydrophilic polymer material and a water repellent film on the discharge side surface of the hydrophilic metal substrate, A nozzle plate having a laminated structure in which a water-repellent film is laminated as an outer surface, and a through-hole serving as a nozzle is provided in the thickness direction of each layer of the laminated structure.

  The nozzle plate of the present invention has a structure in which a water repellent film and a metal plate substrate are joined by a base layer made of a hydrophilic polymer material, and the adhesion and adhesion strength between members are improved. It can be good. As a result, it is possible to provide a highly reliable nozzle plate for an ink jet head that does not leak liquid.

  The nozzle plate for an ink jet head of the present invention comprises a hydrophilic metal plate substrate and a sheet having a water repellent film on a base layer made of a hydrophilic polymer material. The water repellent film forms the outer surface on the discharge side, and the base layer is fixed to the metal plate substrate.

  The nozzle is formed by a through-hole provided in the thickness direction of each member described above, and its inner wall has a hydrophilic metal plate base portion, a hydrophilic polymer material portion, and a water repellent film portion. .

  The metal plate substrate is made of a metal material having a hydrophilic surface because it can secure mechanical strength as a nozzle plate and forms part of the ink flow path. As the metal plate substrate, a nickel sheet, a stainless sheet, or the like can be used. The thickness of the metal plate substrate may be selected according to the intended use even for the inkjet head, but is preferably selected from a range of 40 μm to 150 μm, for example.

  The base layer of the sheet having a water repellent film is formed from a hydrophilic polymer material. As this hydrophilic polymer material, for example, various hydrophilic resins such as polysulfone and polyamide can be used. The type of the base layer can be selected according to the material of the metal plate base so that good adhesive strength and adhesion to the metal plate base can be obtained. The base layer may be any layer that can hold the water-repellent layer and has mechanical strength as a layer provided on the metal plate substrate. The thickness of the base layer is preferably selected from a range of 10 μm or more and 100 μm or less in consideration of processability and strength.

  The hydrophilicity of the base layer for the metal plate substrate and the water-repellent film sheet only needs to be such that the adhesive strength by these adhesives can be increased by the fact that these adhesive surfaces are hydrophilic, and the contact angle of pure water It is preferable that the angle does not exceed 50 °.

  Various methods can be used for joining the base layer to the metal plate substrate. As a simple joining method, a method using an adhesive is simple and preferred. Since the metal plate substrate and the base layer are both hydrophilic, good adhesive strength and adhesion can be obtained between these members.

  Examples of the adhesive for joining them include an epoxy adhesive or a silicon adhesive.

  The water repellent film is provided on the base layer, and a film suitable for the intended use for the ink jet head may be selected from films made of a water repellent material used for forming a water repellent surface. As such a water repellent material, for example, a Teflon-based material can be used. The water-repellent film can be formed by applying a coating liquid containing a water-repellent material to a predetermined surface of the base layer and performing a drying treatment or the like as necessary. The film thickness of the water repellent film is such that the desired water repellency can be imparted to the discharge side surface (outer surface) of the nozzle plate and the meniscus can be easily maintained in the vicinity of the discharge side surface. It is preferable to select from a range of 10 nm to 500 nm.

  The nozzle plate according to the present invention is formed by laminating a sheet having a water-repellent film on the discharge-side surface of a metal plate base provided with a through-hole serving as a nozzle at a predetermined position in advance so that the water-repellent film forms the outer surface. Then, it can be obtained by performing an opening process of extending the through hole to the sheet side and penetrating to the outer surface. Various methods can be used for forming the through hole in the metal plate substrate, but a method combining press working and polishing is simple. Various methods can also be used for opening predetermined portions of a sheet having a water-repellent film bonded on a metal plate substrate. Among these, the opening process by laser irradiation is preferable because it enables simple and accurate opening. In particular, as will be described later, by performing laser irradiation from the ink supply side of the metal plate substrate (the surface opposite to the surface on which the sheet having the water-repellent film is provided), the laser irradiation region on the sheet is reduced. It is automatically regulated by a through-hole provided in advance, and laser irradiation can be performed with high positional accuracy. The laser irradiation is performed with an intensity that does not affect the metal plate substrate and can open the sheet having the water-repellent film. An excimer laser can be suitably used as the laser.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic view of an example of the nozzle plate of the present invention. The nozzle plate is composed of a sheet having a metal plate substrate 1 and a water repellent film bonded and fixed on the metal plate substrate. The sheet having a water repellent film is composed of a sheet (base layer) 2 and a water repellent film 3 made of a polymer material. The nozzle is composed of 4 and 5. The length of the nozzle is defined by the thickness of the sheet having the metal plate substrate and the water repellent film. Moreover, the cross-sectional shape of the nozzle is appropriately selected according to the desired purpose of the inkjet head. In the example shown in FIG. 1, the portion 4 in the metal plate base 1 of the nozzle has a taper portion in which the inner diameter decreases from the ink supply side (lower side in the drawing) to the ejection side (upper side in the drawing) and the inner diameter changes. No straight part. The straight portion communicates with the portion 5 penetrating the sheet 2 and the water repellent film 3 and forms a nozzle opening on the discharge side.

  According to said structure, a water-repellent film can be made thin compared with the case where only a water-repellent resin sheet is joined to a metal plate base | substrate. As a result, it becomes easy to position the meniscus in the vicinity of the nozzle opening on the side where the water repellent film is provided when the ink jet head is incorporated. Further, by reducing the thickness of the sheet having the water repellent film, the opening process using laser irradiation or the like to the sheet can be further facilitated.

Hereinafter, the present invention will be described in more detail with reference to examples.
(Example 1)
FIG. 2A shows a nozzle plate in which nozzles are formed in advance. A nozzle 4 is formed on a nickel sheet 1 having a thickness of 50 μm by press working. The nozzle 4 has a straight portion having a specified length of 10 μm on the discharge side. This is formed in advance by giving a straight punching portion and a taper portion to a punch for pressing. The length of the straight portion is adjusted by the pressing amount of press working so that the specified length becomes 10 μm. After pressing, a polishing process is performed to remove burrs by pressing.

  FIG. 2B shows a schematic cross-sectional view of a sheet having a water repellent film. This sheet has a structure in which a water-repellent film 3 is formed on a polysulfone sheet 2 having a thickness of 20 μm by coating. Application was performed by a spin coating method. As the water repellent, Cytop CTL-809M (Asahi Glass) was diluted to 6% by weight with a diluent CT-Solv180 (Asahi Glass), and the film thickness was adjusted to 200 nm with a spin coater. Thereafter, baking was carried out at 200 ° C. for 1 hour to dry it, and a water repellent film (film thickness: 20 nm) was formed.

Next, adhesive super X8008 (manufactured by ThreeBond) was transferred and applied to the discharge side surface of the nickel sheet, and then a sheet having a water-repellent film was adhered and fixed to form the laminate shown in FIG. At that time, in order to adhere these members uniformly without pressure unevenness on the entire surface, the adhesive solidifies in a pressed state on the entire rubber-like flat plate in a state in which the nickel sheet and the sheet with the water repellent film are brought into alignment contact. Left for 1 day until dry. After drying and solidifying, as shown in FIG. 4, excimer laser light was irradiated from the ink supply side of the laminate. A KrF laser was used as an excimer laser beam. The KrF laser beam has little influence on a metal such as Ni, and the nickel sheet in this embodiment can be used as a mask material for processing. That is, the shape of the nickel sheet 1 itself is not changed by the excimer laser irradiation, the initial shape can be maintained, and the laser irradiation is effectively performed on the portion covering the through hole of the sheet having the water repellent film, and the portion is removed. And the nozzle penetrates. The irradiation conditions were 400 mJ / cm ² and 1000 pulse. In this way, the nozzle plate (FIG. 1) of this example was formed.

  The effect of this example is confirmed. The test was conducted by incorporating the nozzle plate into the inkjet head. First, the adhesive strength and the sealing performance were confirmed by ink leakage at the peripheral portion. The durability of 1000 times of repetition by pressurization of 5 kPa from the common flow path side to the ink was confirmed. Then, the nozzle plate was peeled off and the sealing property was confirmed. This “ink leakage” means that ink enters between the metal plate substrate and the sheet made of a polymer material and between the ink jet head body and the metal plate substrate.

  As a result, no ink leakage was observed, and the adhesiveness had good sealing properties. When the nozzle processing surface was observed by SEM, the polymer material residue by laser removal was hardly seen. Next, as a result of conducting a stability test in the landing direction during continuous discharge, no change was observed in the landing direction even in long-term discharge for 4 hours continuously, and the discharge was stably performed. In addition, the driving frequency dependency of the ejection state was evaluated by the velocity dependency of the main droplet. Stable ejection was possible even at a driving frequency of 10 kHz.

  As described above, in this embodiment, it is possible to stably and easily form a water-repellent film excellent in sealing performance, and to provide a nozzle plate for an inkjet head capable of a stable discharge operation for a long time. .

(Example 2)
FIG. 6A shows a nozzle plate in which nozzles are formed in advance. The nozzle 4 is formed on the SUS304 sheet 1 having a film thickness of 75 μm by press working. After pressing, a polishing process is performed to remove burrs by pressing.

  FIG. 6B shows a schematic cross-sectional view of a sheet having a water repellent film. This sheet has a structure in which a water-repellent film 3 is formed on a polysulfone sheet 2 having a thickness of 30 μm by coating. Application was performed by a dipping method. As a water repellent, Cytop CTL-809M (Asahi Glass Co., Ltd.) was diluted to 6% by weight with a diluent CT-Solv180 (Asahi Glass Co., Ltd.) to obtain a dipping solution. After dipping, baking was performed at 200 ° C. for 1 hour to dry the film, and a water repellent film (film thickness: 20 nm) was formed.

Next, the adhesive super X8008 (manufactured by ThreeBond) was transferred and applied to the upper surface side (discharge side) of the SUS304 sheet, and then the sheet with a water-repellent film was adhered and fixed to form the laminate shown in FIG. At that time, in order to adhere these members uniformly without pressure unevenness on the entire surface, the adhesive solidifies in a pressed state on the entire rubber-like flat plate in a state where the SUS304 sheet and the sheet with the water repellent film are in alignment contact. Left for 1 day until dry. After drying and solidifying, excimer laser light was irradiated from the ink supply side of the laminate as shown in FIG. A KrF laser was used as an excimer laser beam. The KrF laser beam has little influence on metals such as SUS, and the SUS sheet in this embodiment can be used as a mask material for processing. In other words, the shape of the SUS sheet 1 itself is not changed by the excimer laser irradiation, the initial shape can be maintained, and the laser irradiation is effectively performed on the portion covering the through hole of the sheet having the water repellent film, and the portion is removed. And the nozzle penetrates. Irradiation conditions were 200 mJ / cm ² and 500 pulse. Thus, the nozzle plate (FIG. 5) of this example was formed.

  As in Example 1, confirmation of adhesion with an adhesive, stability in the landing direction for a long time, and stability at a high frequency were all confirmed, and good results were obtained.

  As described above, in this embodiment, it is possible to stably and easily form a water-repellent film having excellent adhesion, and it is possible to provide a nozzle plate for an inkjet head capable of performing a discharge operation stably for a long time. .

  As mentioned above, although the form of one Example was demonstrated in detail, this invention is not limited to this embodiment.

It is typical sectional drawing which shows the nozzle plate of one Embodiment of this invention. It is typical sectional drawing which shows the structure of the metal plate base | substrate in one Example of this invention, and a sheet | seat with a water repellent film. It is typical sectional drawing which shows the structure of the laminated body before laser processing. It is a figure which shows laser processing. It is typical sectional drawing which shows the nozzle plate of one Example of this invention. It is typical sectional drawing which shows the structure of the metal plate base | substrate in one Example of this invention, and a sheet | seat with a water repellent film. It is typical sectional drawing which shows the structure of the laminated body before laser processing. It is a figure which shows laser processing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal plate base | substrate 2 Sheet | seat which consists of polymeric materials 3 Water repellent film 4 Part in the base | substrate of a nozzle 5 Part in the sheet | seat of a nozzle 6 Laser beam

Claims (7)

In a method for manufacturing a nozzle plate for an inkjet head,
A sheet having a water-repellent film on the surface of a base layer made of a hydrophilic polymer material is laminated on the surface of the liquid discharge side where a through-hole serving as a nozzle of a hydrophilic metal plate substrate opens, with the water-repellent film as an outer surface. And a process of
Opening a portion corresponding to the opening of the through hole of the sheet to open the nozzle;
A method for producing a nozzle plate, comprising:   The portion of the through hole provided on the metal plate base is composed of a tapered portion and a straight tubular portion, and these portions are arranged in this order from the ink supply side to the discharge side. The manufacturing method according to claim 1.   The manufacturing method according to claim 1, wherein the opening of the sheet is performed by laser irradiation.   The manufacturing method according to claim 3, wherein the laser irradiation is excimer laser irradiation.   A nozzle plate obtained by the manufacturing method according to claim 1. In the nozzle plate for inkjet heads,
A sheet having a base layer made of a hydrophilic polymer material and a water repellent film on the discharge side surface of the hydrophilic metal substrate, and having the water repellent film as an outer surface is laminated. A nozzle plate, wherein a through-hole serving as a nozzle is provided in the thickness direction of each layer.   The portion of the through hole provided on the metal plate base is composed of a tapered portion and a straight tubular portion, and these portions are arranged in this order from the ink supply side to the discharge side. The nozzle plate according to claim 6.

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