JP2023161162A - Liquid ejection head, liquid ejection device, and manufacturing method for liquid ejection head - Google Patents

Abstract

To provide a liquid ejection head which makes high precision and nozzle plate deformation inhibition compatible and to provide a manufacturing method for the same.SOLUTION: A liquid ejection head has: a nozzle plate provided with an ejection port for ejecting a liquid; a flow-path formation member adjacent to the nozzle plate and provided with a pressure chamber connected to the ejection port via a nozzle; and an energy generation element configured to generate energy for ejecting the liquid into the pressure chamber; wherein the nozzle plate has a resin layer and a deformation inhibition layer whose Young's modulus is 50 GPa or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid ejection head, a liquid ejection device, and a method of manufacturing a liquid ejection head.

In an inkjet printer as a liquid ejection device, in order to achieve higher definition and higher quality printing, it is required to improve the processing accuracy of the liquid ejection head and make the liquid ejection head more precise.

Patent Document 1 discloses a method for manufacturing a piezoelectric liquid ejection head, in which the nozzle plate of the liquid ejection head is formed of photosensitive resin, thereby improving processing accuracy and achieving higher definition than etching processing. is listed. Furthermore, by using photosensitive resin as the nozzle plate, it becomes possible to pattern the nozzles on the liquid repellent layer and the nozzle plate at the same time. It is also stated that compared to the method of forming a liquid-repellent layer after nozzle formation, this method prevents the water-repellent layer from entering the nozzle, making it possible to achieve higher definition and lower costs. .

JP2010-36473 Publication

In the piezoelectric liquid ejection head manufactured by the manufacturing method described in Patent Document 1, the nozzle plate formed of photosensitive resin is easily deformed, resulting in a large loss of ejection energy applied to the liquid from the piezoelectric element, and the ejection may affect.

Therefore, an object of the present invention is to provide a liquid ejection head that achieves both high definition and suppression of nozzle plate deformation, and a method for manufacturing the same.

In order to solve the above problems, the present invention includes a nozzle plate provided with a discharge port for discharging liquid, and a pressure chamber adjacent to the nozzle plate and connected to the discharge port via a nozzle. In the liquid ejection head, the nozzle plate includes a flow path forming member configured to eject the liquid into the pressure chamber, and an energy generating element configured to generate energy for ejecting the liquid into the pressure chamber. Provided is a liquid ejection head having a deformation suppressing layer having a deformation rate of 50 GPa or more.

Further, the present invention provides a nozzle plate provided with a discharge port for discharging a liquid, and a flow path formed with a pressure chamber adjacent to the nozzle plate and connected to the discharge port via a nozzle. and an energy generating element configured to generate energy for ejecting the liquid into the pressure chamber, wherein the nozzle plate includes a liquid repellent layer and a photosensitive material. and a deformation suppressing layer having a Young's modulus of 50 GPa or more, the method includes forming at least one of the photosensitive material layer and the liquid repellent layer with a dry film resist. A method of manufacturing a liquid ejection head is provided.

According to the present invention, a liquid ejection head, a liquid ejection device, and a method for manufacturing a liquid ejection head that achieve both high definition and suppression of nozzle plate deformation are provided.

FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. It is a figure showing an example of a nozzle plate of the present invention. It is a figure showing an example of a nozzle plate of the present invention. FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a method for manufacturing a liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a method for manufacturing a liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention.

Examples of preferred embodiments of the present invention will be described below. The liquid ejection head of the present invention can be applied to devices such as printers, copying machines, facsimiles with communication systems, word processors with printer sections, and even industrial recording devices that are combined with various processing devices. The liquid ejection head of the present invention can also be used for applications such as biochip production and electronic circuit printing, for example. Each of the embodiments described below is a suitable example of the present invention, and has various technically preferable structural features. However, the present invention is not limited to the embodiments and other specific examples described below, and various changes can be made without departing from the technical idea.

FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. As shown in FIG. 1, the liquid ejection head includes a nozzle plate 10 provided with ejection ports 30 for ejecting liquid, and a pressure that is connected to the nozzle plate 10 and connected to the ejection ports 30 via the nozzles 20. It has a flow path forming member 1 in which a chamber 2 is provided. The flow path forming member 1 further includes an energy generating element configured to generate energy for discharging the liquid into the pressure chamber 2. As the energy generating element, any element known in the field of liquid ejection heads can be used as appropriate. Examples include a heater element, an ultrasonic element, an element that discharges liquid using electric energy or magnetic energy, and the like. In this embodiment, a case will be described in which a piezoelectric element 3 is used as the energy generating element. Further, the nozzle plate 10 includes a deformation suppressing layer 11 and a photosensitive material layer 12, and may further include a liquid repellent layer 13. In addition, in the nozzle plate 10 , the nozzle 20 has a first nozzle portion 21 formed on the deformation suppressing layer 11 and a second nozzle portion 22 formed outside the deformation suppressing layer 11 .

In a liquid ejection head using a piezoelectric element, energy loss due to deformation of the nozzle plate is generally a problem when applying ejection energy to liquid by vibrating the piezoelectric element. Therefore, Si, stainless steel, or the like, which has a relatively large Young's modulus, is often used for the nozzle plate and flow path forming member that receive the pressure generated from the piezoelectric element via the liquid. On the other hand, in the present invention, the photosensitive material layer 12 is used in the nozzle plate for the purpose of improving the processing accuracy of the nozzle plate and increasing the definition of the liquid ejection head. The photosensitive material layer 12 is preferably a resin layer using a photosensitive resin from the viewpoint of improving processing accuracy, and in particular, from the viewpoint of improving durability, it is preferably a resin layer using a negative photosensitive resin. More preferred. Examples of the photosensitive resin include UV-curable epoxy, acrylic, urethane, polyimide, silicone, and resins having a molecular structure that is a combination of these. Mixtures of these resins may also be used.

Here, when using the photosensitive material layer 12 made of resin in the nozzle plate 10 for the purpose of improving processing accuracy, the nozzle plate 10 has a deformation suppressing layer 11 for the purpose of compensating for the softness of the nozzle plate 10. This provides the effect of reducing deformation of the nozzle plate 10 when force is applied to the liquid from the piezoelectric element 3. The deformation of the nozzle plate 10 is suppressed by adopting a configuration in which the deformation suppressing layer 11 receives the pressure applied to the nozzle plate 10 via the liquid from the piezoelectric element 3 when discharging the liquid.

The Young's modulus of the deformation suppressing layer 11 is preferably 50 GPa or more. Generally, the Young's modulus of resins is lower than that of Si or stainless steel, and is reported to be about 2 GPa for epoxy resins, and less than 5 GPa even for resins with large Young's modulus. Therefore, if the Young's modulus of the deformation suppressing layer 11 is 50 GPa, the value will be 10 times or more as compared to a resin having a high Young's modulus. Furthermore, the Young's modulus of the deformation suppressing layer 11 is more preferably 130 GPa or more, particularly preferably 193 GPa or more. If it is 130 GPa, a Young's modulus higher than that of Si can be obtained, and if it is 193 GPa or higher, a Young's modulus higher than that of stainless steel can be obtained.

As the material for the deformation suppressing layer 11, it is preferable to use Si because it can be processed by either wet etching or dry etching and can easily improve processing accuracy. When using a Si single crystal substrate, it is more preferable that the 111 plane, which is a crystal orientation with a high Young's modulus, overlaps the pressure chamber 2. Stainless steel, Ni, Ir, Ta, W, Mo, Cr, Co, Fe, Ru, SiC, TiC, _WC , _B4C , _ZrO2 , _Al2O3 , AlN, _{Si3N4 ,} TiN, diamond, etc. may also be used. Further, an alloy, a laminated structure, or a mixed material of these may also be used. These materials may be processed by wet etching or dry etching. If etching processing is difficult, laser processing, electron beam processing, ion beam processing, sandblasting, cutting processing, etc. may be used. Among these, femtosecond laser processing or water jet processing, which can reduce the thermal effect during processing, can be used. Laser processing is preferred.

Next, the liquid repellent layer 13 will be explained. By using the structure of the present invention, the nozzle plate 10 has a structure in which the liquid repellent layer 13, the photosensitive material layer 12, and the deformation suppressing layer 11 are laminated in this order from the surface side. This is more preferable because the second part 22 of the nozzle can be formed on the layer 12 all at once, and the effect of reducing the penetration of the liquid-repellent layer 13 into the first part 21 of the nozzle is achieved. Furthermore, in order to obtain the liquid-repellent effect of the liquid-repellent layer 13 and to perform liquid ejection well, a configuration in which the liquid-repellent layer 13 is exposed on the surface is preferable.

Note that heat and solvent in the process of forming the liquid-repellent layer 13 may affect the photosensitive material layer 12. In the configuration of this embodiment, since the deformation suppressing layer 11 is supported by the photosensitive material layer 12, deformation due to softening and internal stress of the photosensitive material layer 12 is reduced, and high-definition processing of the nozzle plate 10 is possible. The effect is that it becomes possible.

For the same reason as the photosensitive material layer 12, the material for the liquid repellent layer 13 preferably contains a photosensitive material, more preferably contains a photosensitive resin, and even more preferably contains a negative photosensitive resin. . Further, it is more preferable that the photosensitivity of the photosensitive material layer 12 and the liquid repellent layer 13 be the same so that the dimensions of the liquid repellent layer 13 and the photosensitive material layer 12 can be matched even when they are exposed simultaneously.

Further, it is preferable that the contact angle of pure water on the deformation suppressing layer 11 is less than 90°, and that the contact angle of pure water on the photosensitive material layer 12 is less than 90°. In this case, the liquid easily wets the deformation suppressing layer 11 and the photosensitive material layer 12. Therefore, the liquid forms a meniscus within the second portion 22 of the nozzle, and the discharge is stabilized. Here, the contact angle of liquids other than pure water tends to be lower than that of pure water, and the contact angle of aqueous liquids containing additives or liquids containing a large amount of organic solvents is often less than 90°. Therefore, pure water was used as the standard for determining the contact angle. Even if the contact angle of various liquids is less than 90°, the same effect can be obtained. Furthermore, it is preferable that the difference between the contact angle of pure water in the deformation suppressing layer 11 and the contact angle of pure water in the photosensitive material layer 12 is small, preferably 50 degrees or less, and more preferably 30 degrees or less. Further, it is preferable that the nozzle 20 of the liquid ejection head is directed downward in the direction of gravity so that the effect of increasing the force of supplying the liquid to the nozzle 20 can be obtained. The state of the meniscus may be controlled by adjusting the pressure applied to the liquid to be increased or decreased using a pump or the like connected to the liquid ejection head.

Further, a layer having the effect of strengthening the bond between the liquid repellent layer 13 and the photosensitive material layer 12 may be placed within the photosensitive material layer 12, within the liquid repellent layer 13, or at the interface between the photosensitive material layer 12 and the liquid repellent layer 13. It may be introduced in one. For example, a layer that strengthens the bond between the liquid repellent layer 13 and the photosensitive material layer 12 can be introduced by using a silane coupling material or by combining plasma treatment, UV treatment, etc.

Further, by adding a filler material to the photosensitive material layer 12 or the liquid-repellent layer 13, the effect of suppressing deformation of the nozzle plate 10 can be enhanced. As the filler material, a material having a higher Young's modulus than the photosensitive material layer 12 or the liquid repellent layer 13 is preferable. As with the deformation suppressing layer 11, the Young's modulus of the filler material is preferably 50 GPa or more, more preferably 130 GPa or more, and particularly preferably 193 GPa or more.

Further, as shown in FIG. 2(A), the deformation suppressing layer 11 may include a support layer 111 having a Young's modulus of 50 GPa or more and a functional layer 112. The functional layer 112 may be formed of multiple layers, may be formed partially with respect to the support layer 111, and may be formed inside the deformation suppressing layer 11 between two or more layers of the support layer 111. It's okay if it's done. For example, when the functional layer 112 has a lower reflectance than the support layer 111 for light at a wavelength to which the photosensitive material layer 12 is sensitive, the reflected light that the photosensitive material layer 12 receives from the deformation suppressing layer 11 is reduced. Effects can be obtained. Further, the surface of the functional layer 112 has a siloxane bond, and by using a silane coupling material at the interface between the photosensitive material 12 and the functional layer 13, a chemical bond can be formed, and the photosensitive material layer 12 and the liquid repellent The effect of improving adhesion with layer 13 can be obtained. The functional layer 112 is provided with a function as, for example, a wiring layer, an insulating layer, a semiconductor layer, an antireflection layer, an antidiffusion layer, a protective layer, a planarizing layer, an adhesion improving layer, an adhesive layer, or an etching stop layer. Good too. Alternatively, the functional layer 112 may be patterned to provide a function combining various electronic components such as a circuit, a sensor, a memory, and a battery. Note that a material having a Young's modulus of less than 50 GPa may be used for the functional layer 112.

Next, the detailed configuration of the nozzle plate 10 will be explained. Various known shapes may be used for the cross-sectional shape of the nozzle 20. Specifically, a substantially circular shape, an ellipse, a polygon, or a shape composed of various straight lines and curves can be used. Further, a protrusion may be provided on the discharge port 30 for the purpose of reducing mist or the like.

In addition, in order to stabilize the position of the meniscus at the outermost surface of the second part 22 of the nozzle, the inner diameter of the second part 22 of the second nozzle must be smaller than the inner diameter of the first part 21 of the first nozzle. It is preferable that the nozzle 21 and the nozzle 22 have substantially the same central axis. Here, as the inner diameter of the nozzle, for example, if the nozzle shape is approximately circular, the diameter may be used, and if the nozzle shape is elliptical, the major axis may be used. Furthermore, as will be described later, when the first portion 21 of the nozzle has a multi-stage structure or a tapered structure, the inner diameter of the surface in contact with the deformation suppressing layer 12 may be used. As a result, the processing accuracy of the outermost surface of the second portion 22 of the nozzle becomes the lithography accuracy of the photosensitive material 12, and the processing accuracy is higher than that of the first portion 21 of the nozzle within the deformation suppressing layer 11 formed by lithography and etching. This is more preferable because the effect can be easily enhanced.

As described above, when the inner diameter of the second part 22 of the nozzle is smaller than the first part 21 of the nozzle, and the central axes of the nozzle 21 and the nozzle 22 are substantially the same, the case shown in FIG. 2(B) As shown, a protruding portion 121 from the deformation suppressing layer 11 that does not contact the deformation suppressing layer 11 is formed in the photosensitive material layer 12 . Here, the photosensitive material layer 12 and the liquid repellent layer 13 are deformed due to the internal stress of the photosensitive material layer 12 and the liquid repellent layer 13. Since the protruding part 121 is not fixed to the deformation suppressing layer 11, it is easily deformed, and the larger the length a of the protruding part 121, the greater the deformation due to the internal stress. Here, if the length a of the protruding part is equal to or less than the total thickness of the photosensitive material layer 12 and the liquid-repellent layer 13, the proportion of the protruding part that can be deformed can be reduced, which has the effect of reducing the deformation of the protruding part 121. This is more preferable because it provides the following. Further, by reducing the ratio of the length a of the protruding portion to the inner diameter of the first portion 21 of the nozzle, it is possible to obtain the effect of reducing hardened foreign matter inside the nozzle. Therefore, the value of the length a of the protruding portion 121 is preferably 6% or less with respect to the inner diameter of the first portion 21 of the nozzle, more preferably 5% or less, and even more preferably 4% or less, It is even more preferable that it is 3% or less. In this case, it is preferable that the difference between the inner diameter of the first part 21 of the nozzle and the inner diameter of the second part 22 of the nozzle is 12% or less with respect to the inner diameter of the first part 21 of the nozzle, and more preferably 10% or less. It is preferably 8% or less, more preferably 6% or less, and even more preferably 6% or less. Here, the hardened foreign matter in the nozzle is a foreign matter caused by hardening of the photosensitive material in an area where the photosensitive material is not desired to be hardened.

Further, by making the thickness of the deformation suppressing layer 11 larger than the total thickness of the photosensitive material layer 12 and the liquid repellent layer 13, the effect of suppressing the deformation of the nozzle plate 10 is enhanced, but since the length of the nozzle 20 changes, Affects discharge. Therefore, in order to achieve both a deformation suppressing effect and good ejection of liquid, the thickness of the deformation suppressing layer 11 is preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and 20 μm or less. It is even more preferable. In addition, in order to effectively obtain the deformation suppressing effect, the thickness of the deformation suppressing layer 11 is preferably 5 μm or more, more preferably 10 μm or more.

Further, the total thickness of the photosensitive material layer 11 and the liquid-repellent layer 13 is preferably 10 μm or less, more preferably 5 μm or less, and even more preferably 1 μm or less. At this time, by reducing the total thickness of the photosensitive material layer 11 and the liquid repellent layer 13, it may be possible to reduce abnormalities in liquid ejection. In addition, in order to stably exhibit liquid repellency, the total thickness is preferably 0.02 μm or more, more preferably 0.05 μm or more.

Next, the detailed configuration of the nozzle 20 will be explained. FIGS. 3A and 3B are enlarged views of the nozzle 20 in the present invention.

As shown in FIG. 3A, by forming the first portion 21 of the nozzle in a multi-stage structure, it is possible to widen the design range that achieves both deformation suppressing effects and good discharge. Specifically, even if the deformation suppressing layer 11 is made thicker to suppress deformation, the design range of the liquid ejection speed and ejection amount can be adjusted, or when circulating the liquid to prevent ejection failure. The effect of increasing circulation efficiency can be obtained. Similar effects can be obtained even if the first portion 21 of the nozzle is tapered, and a multi-stage structure and a tapered structure may be combined.

As shown in FIG. 3A, the photosensitive material layer 12 and deformation are suppressed by forming a nozzle wall adhesion part 122 in which the photosensitive material 12 enters from the second part 22 of the nozzle to the first part 21 of the nozzle. This is more preferable because the adhesion area of the layer 11 becomes wider and the adhesion is improved. The first portion 21 of the nozzle may have a multi-stage structure, with some stages being in contact with the nozzle wall contact portion 122 and others not being in contact with the nozzle wall contact portion 122. Whether the photosensitive material layer 12 is formed to enter the first portion 21 of the nozzle can be determined by observing the cross section of the nozzle 20 or analyzing the composition.

As shown in FIG. 3(B), the photosensitive material layer 12 and the liquid-repellent layer 13 may form a tapered shape. If the taper angle θ is large, the discharge speed can be increased, so it is more preferably 2° or more, even more preferably 5° or more, and even more preferably 10° or more. Here, the photosensitive material layer 12 may have a multi-stage structure, or may have a structure that combines a multi-stage structure and a tapered shape.

Next, an example of the configuration of the ejection head in the present invention will be described. FIG. 4 is a diagram showing an example of a liquid ejection head of the present invention. As shown in FIG. 4(A), a nozzle plate 10 is connected to a flow path forming member 1 having a pressure chamber 2, and the pressure chamber 2 and the nozzle plate 10 are adjacent to each other. When driving the piezoelectric element 3 to apply ejection energy to the liquid, pressure is applied to the nozzle plate 10 via the liquid. At this time, the deformation suppressing layer 11 of the present invention effectively works to suppress deformation of the nozzle plate 10.

As shown in FIG. 4(B), a configuration in which a flow path exists between the piezoelectric element 3 and the nozzle plate 10 can also be used. Even in this case, when the piezoelectric element 3 is driven to apply energy to the liquid, pressure is applied to the nozzle plate 10 through the liquid. Therefore, the pressure chamber 2 including the flow path can be regarded as the pressure chamber 2, and the deformation suppressing layer 11 of the present invention works effectively.

As shown in FIG. 4C, another configuration in which the piezoelectric element 3 and the nozzle plate 10 are separated can also be used. Even in this case, the energy applied to the liquid by driving the piezoelectric element 3 is applied to the nozzle plate 10 via the liquid, so that the pressure chamber 2 including the flow path can be considered. Therefore, the deformation suppressing layer 11 of the present invention works effectively. Further, pressure also propagates through the liquid in the direction of the liquid supply port 31, which is a channel for supplying liquid to the pressure chamber 2. As in this configuration, when there is a part adjacent to the nozzle plate 10 in the middle of the flow path of the liquid supply port 31, the deformation suppressing layer 11 of the present invention, which applies pressure to the nozzle plate 10 through the liquid, is effective. work.

Further, the liquid ejection head may be processed other than the nozzle 20. FIG. 5 is a diagram showing an example of a liquid ejection head of the present invention. FIG. 5(A) is a cross-sectional view, and FIG. 5(B) is a top view corresponding to A-A' in FIG. 5(A).

As shown in FIG. 5(A), the deformation suppressing layer 11 is composed of a support layer 111 and a functional layer 112. The functional layer 112 can be used, for example, as an etching stop layer. A first portion 21 of a nozzle is formed in the deformation suppressing layer 11 . Further, a second portion 22 of the nozzle is also formed on the photosensitive material layer 12 and the liquid repellent layer 13. The flow path forming member 1 has a pressure chamber 2, a piezoelectric element 3, and a liquid supply port 31.

Here, a processing pattern other than the nozzle 20 can be formed on at least one of the deformation suppressing layer 11, the photosensitive material layer 12, and the liquid repellent layer 13 to provide various functions. For example, by forming the slits 41 in the nozzle plate 10, the effect of adjusting the rigidity balance of the entire substrate, the effect of adjusting the flow of adhesive when bonding the nozzle plate 10 and the flow path forming member 1 with adhesive, or the effect of adjusting the flow of the adhesive The effect of improving adhesion can be obtained. Further, the pattern 42 may be formed on the nozzle plate 10. In this case, by further removing the photosensitive material layer 12 and the liquid repellent layer 13 near the pattern 42, the visibility of the pattern 42 can be improved. A pattern 43 formed by processing the photosensitive material layer 12 and the liquid-repellent layer 13 may be formed in a portion where the processed pattern 42 is not provided. These processing patterns can be processed simultaneously with the first part 21 of the nozzle or the second part 22 of the nozzle, so in the present invention, processing is possible without providing a new processing step. These processing patterns are used to identify the wafer or chip to be processed, measure the width and depth of the pattern, monitor the state during processing or after processing, and align the wafer or chip using the processing pattern as an alignment mark. It can be used for etc.

Next, an example of a method for manufacturing a liquid ejection head according to the present invention will be described. FIG. 6 is a diagram showing an example of a method for manufacturing a liquid ejection head of the present invention.

As shown in FIG. 6A, a structure 120 having a flow path forming member 1 having a pressure chamber 2 and a piezoelectric element 3, and a deformation suppressing layer 11 having a first portion 21 of a nozzle is prepared. Note that the flow path forming member 1 and the deformation suppressing layer 11 can be bonded together using adhesive bonding, anodic bonding, surface activation bonding, etc., but there is a degree of freedom in selecting the material of the deformation suppressing layer 11 and a degree of freedom in processing. Therefore, it is preferable to use adhesive bonding.

Here, by using Si as the deformation suppressing layer 11 and processing the first portion 21 of the nozzle using the Bosch process, a scallop can be formed on the wall surface of the first portion 21 of the nozzle. In the process of forming the photosensitive material layer 12, which will be described later, by processing the photosensitive material layer 12 so that it comes into contact with this scallop, the adhesion between the deformation suppressing layer 11 and the photosensitive material layer 12 due to the anchor effect is improved. This is preferable because it provides the following.

Next, as shown in FIG. 6(B), a photosensitive material layer 12 is formed on the structure 120. Here, the photosensitive material layer 12 may be formed by a known method, but it is preferable to form it using a dry film resist because it is easy to control the amount of penetration into the first part 21 of the nozzle or the pressure chamber 2. . In this case, the shape of the first part 21 of the nozzle of the deformation suppressing layer 11 is made multi-stage, and the photosensitive material layer 12 is formed so as to fill the uppermost stage of the first part 21 of the nozzle, so that the photosensitive material is formed in the nozzle. It may be controlled so that it is difficult to enter the second and subsequent stages of the first portion 21.

Further, the photosensitive material layer 12 may have a multilayer structure including a plurality of materials having different photosensitivity. For example, by arranging a highly photosensitive layer on the liquid repellent layer 13 side and a layer with low photosensitivity on the deformation suppressing layer 11 side, the liquid repellent layer can be The effect of reducing the reflection influence that the layer 13 receives from the photosensitive material layer 12 and the deformation suppressing layer 11 can be obtained.

Next, as shown in FIG. 6(C), a liquid repellent layer 13 is formed. Here, the liquid-repellent layer 13 may be formed by a known method, such as slit coating, spin coating, spray coating, screen printing, etc. In order to reduce deformation of the photosensitive material layer 12 when forming the liquid-repellent layer 13, it is preferable to form the liquid-repellent layer 13 with a reduced amount of solvent, and the liquid-repellent layer 13 is formed using a dry film resist. is more preferable. Further, as another method for reducing deformation of the photosensitive material layer 12, it is preferable to form the photosensitive material layer 12 so as to enter the first portion 21 of the nozzle. This can reduce the flow of the photosensitive material due to the solvent or heat during formation of the liquid-repellent layer 13. Furthermore, when forming the liquid-repellent layer 13 by coating, it is preferable that the solvent used to form the liquid-repellent layer 13 has a composition that does not easily dissolve the photosensitive material layer 12. By taking such measures, the effect of reducing deformation of the photosensitive material layer 12 can be obtained.

Further, by irradiating the liquid repellent layer 13 with energy after forming the liquid repellent layer 13, the liquid repellent components in the liquid repellent layer 13 can be segregated on the surface, and the effect of improving the liquid repellent performance can be obtained. For the energy irradiation, heat treatment using a hot plate or oven can be used. Alternatively, electromagnetic waves such as lamps, lasers, and microwaves may be used, or irradiation with electron beams, ion beams, gas jets, plasma treatment, etc. may be used. These energies may be irradiated continuously or may be irradiated instantaneously at high output.

Next, as shown in FIG. 6(D), a second portion 22 of the nozzle is formed on the liquid repellent layer 13 and the photosensitive material layer 12. The second portion 22 of the nozzle may be formed using known methods. For example, a series of steps such as exposure, PEB (Post exposure bake), and development can be used. Here, in various heat treatments including PEB, it is preferable to increase the heating temperature in stages, since this is effective in reducing deformation of the photosensitive material layer 12. Additional heat treatment may be performed after development.

Next, an embodiment different from that shown in FIG. 6 will be described regarding the method of manufacturing a liquid ejection head according to the present invention. FIG. 7 is a diagram showing an example of a method for manufacturing a liquid ejection head of the present invention. As shown in FIG. 7(A), a structure 120 is prepared. Next, as shown in FIG. 7(B), the film 14 formed on the support member 50 is transferred to the structure 120. Here, the film 14 can be a laminate of a layer for the photosensitive material layer 12 and a layer for the liquid-repellent layer 13.

Next, as shown in FIG. 7C, the film 14 is patterned while the support member 50 is peeled off to form the second portion 22 of the nozzle. By applying force via the support member 50 to the film 14 transferred so as to cover the first portion 21 of the nozzle, cohesive failure occurs in the film 14 at the edge of the first portion 21 of the nozzle, and the film 14 is patterned to form the second portion 22 of the nozzle. Here, in order to pattern the film 14 so that the second part 22 of the nozzle does not shift from the edge of the first part 21 of the nozzle, it is effective to reduce the thickness of the film 14. Therefore, the thickness of the film 14 is preferably 1 μm or less, more preferably 0.5 μm or less, even more preferably 0.2 μm or less, and even more preferably 0.1 μm or less.

Furthermore, as shown in FIG. 7(D), by irradiating the film 14 with energy, the liquid-repellent component can be segregated to form a state in which the photosensitive material layer 12 and the liquid-repellent layer 13 are sufficiently separated. can. Here, the liquid-repellent layer 13 has a composition such that the contact angle of pure water is 90° or more, and the photosensitive material layer 12 has a composition such that the contact angle of pure water is less than 90°. Therefore, whether phase separation has occurred can be evaluated by scraping the photosensitive material layer 12 and the liquid-repellent layer 13 and measuring the contact angle of pure water. Alternatively, it can also be estimated from a composition analysis in the depth direction of the nozzle plate 10.

Further, for the film 14, a mixture of raw materials for the photosensitive material layer 12 and the liquid-repellent layer 13 can also be used. As in the case where a laminate of the photosensitive material layer 12 and the liquid repellent layer 13 is used as the film 14, by irradiating the film 14 with energy, a state in which the photosensitive material layer 12 and the liquid repellent layer 13 are sufficiently separated can be achieved. can be formed. By using this embodiment in which the photosensitive material layer 12 and the liquid repellent layer 13 are formed at once, the total thickness of the photosensitive material layer 12 and the liquid repellent layer 13 can be made thin, and in addition, the number of formation steps can be reduced. . Further, if a material that is liquid at room temperature of 25° C. is used as the mixture of raw materials for the photosensitive material layer 12 and the liquid-repellent layer 13, phase separation at room temperature becomes possible, and the process is simplified.

In the process of forming the nozzle 20, exposure may be performed by irradiating the entire surface, which has the effect of simplifying the process. Also, PEB, development or additional heat curing can be performed. Incidentally, development does not necessarily need to be performed, or heat treatment that also serves as PEB and additional heat curing may be performed, and in either case, the effect of simplifying the process can be obtained.

As shown in FIGS. 6 and 7, the order of forming each layer is to form the photosensitive material layer 12 and the liquid-repellent layer 13 after bonding the deformation suppressing layer 11 and the channel forming member 1. is preferred. If the photosensitive material layer 12 and the liquid-repellent layer 13 are first formed on the deformation suppressing layer 11, the deformation suppressing layer 11 will be processed as a single unit, but since the deformation suppressing layer 11 alone is thin and difficult to handle, it is difficult to support it. Parts are often required. Therefore, by first joining the deformation suppressing layer 11 to the flow path forming member 1, the flow path forming member 1 acts as a support member for the deformation suppressing layer 11, making handling easier.

In the above embodiments, a liquid ejection head using a piezoelectric element as an energy generating element for ejecting liquid has been described, but the present invention works effectively even when a device other than a piezoelectric element is used as an energy generating element. Here, FIG. 8 shows a liquid ejection head when a heating element is used as the energy generating element.

As shown in FIG. 8, the liquid ejection head includes a flow path forming member 1 and a nozzle plate 10 connected to the flow path forming member 1. The flow path forming member 1 includes a pressure chamber 2, a heater 4, and a liquid supply port 31, and the nozzle plate 10 includes a deformation suppressing layer 11, a photosensitive material layer 12, a liquid repellent layer 13, has. The nozzle plate 10 has a nozzle 20, and the nozzle 20 has a first part 21 of the nozzle formed in the deformation suppressing layer 11 and a second part 22 of the nozzle formed of a material other than the deformation suppressing layer 11. In this configuration as well, the effect of suppressing deformation of the nozzle plate 10 by the deformation suppressing layer 11 can be obtained, similar to the liquid ejection head using a pressure element as an energy generating element.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the Examples.

<Example>
A liquid ejection head having the configuration shown in FIG. 1 was formed. A Si substrate was used as the flow path forming member 1, on which a piezoelectric element 3 made of PZT (lead zirconate titanate), a drive circuit (not shown), a liquid supply port (not shown), and a pressure chamber 2 were formed. . Si was used as the material for the deformation suppressing layer 11. After the flow path forming member 1 and the deformation suppressing layer 11 were bonded using an adhesive, the deformation suppressing layer 11 was thinned to a thickness of 100 μm. Subsequently, a first portion 21 of a nozzle having a diameter of 30 μm was formed on the deformation suppressing layer 11 by a Bosch process using a photoresist as a mask member.

Next, a negative photosensitive epoxy resin formed into a dry film with a thickness of 5 μm was transferred onto the deformation suppressing layer 11 as the photosensitive material layer 12 . Subsequently, a liquid repellent containing a negative type photosensitive epoxy resin was applied onto the photosensitive material layer 12 using a slit coater to form a liquid repellent layer 13, and then baked. Next, the photosensitive material layer 12 and the liquid repellent layer 13 were exposed using a photomask whose size was adjusted to have a diameter of 29 μm, and PEB, development, and additional heat treatment were performed to form the second portion 22 of the nozzle. . Through the above steps, a liquid ejection head was obtained. The obtained liquid ejection head was attached to an inkjet printer main body (not shown), and an ink tank (not shown) containing ink was attached to the liquid ejection head. In this way, an inkjet printer as a liquid ejecting device was constructed.

<Comparative example>
A liquid ejection head was formed in which the deformation suppressing layer 11 shown in FIG. 1 was replaced with a photosensitive resin. Note that a negative photosensitive epoxy resin was used as the photosensitive resin. The Young's modulus of the epoxy resin is 50 GPa or less, which is required for the deformation suppressing layer of the present invention. The flow path forming member 1 had the same structure as that of the previous example. As a member corresponding to the deformation suppressing layer 11, five sheets of negative photosensitive epoxy resin formed into a dry film with a thickness of 20 μm were bonded together. Subsequently, the dry film was exposed to light, PEB, and developed to form the first portion 21 of the nozzle having a diameter of 30 μm. Next, the photosensitive material layer 12, the liquid-repellent layer 13, and the second portion 22 of the nozzle were formed in the same manner as in the example to obtain a liquid ejection head. Using the obtained liquid ejection head, an inkjet printer was constructed in the same manner as in the example. When the inkjet printers of the example and the comparative example were compared, it was found that when the liquid ejection head of the example was used, the ejection frequency was higher than when the liquid ejection head of the comparative example was used. . Further, in the liquid ejection head of the comparative example, the rate of decrease in the ejection speed and the rate of non-ejection were sometimes increased.

1 Channel forming member 2 Pressure chamber 3 Piezoelectric element 4 Heater 10 Nozzle plate 11 Deformation suppressing layer 12 Photosensitive material layer 13 Liquid repellent layer 111 Support layer 112 Functional layer 20 Nozzle 21 First part of nozzle 22 Second part of nozzle 30 Discharge port 31 Liquid supply port 50 Support member 121 Protrusion part a Length of protrusion part 122 Nozzle wall contact part

Claims (18)

a nozzle plate provided with a discharge port for discharging liquid;
a flow path forming member provided with a pressure chamber adjacent to the nozzle plate and connected to the discharge port via a nozzle;
A liquid ejection head comprising: an energy generating element configured to generate energy for ejecting the liquid into the pressure chamber;
The nozzle plate is a liquid ejection head including a resin layer and a deformation suppressing layer having a Young's modulus of 50 GPa or more. The liquid ejection head according to claim 1, wherein the energy generating element is a piezoelectric element. The liquid ejection head according to claim 1, wherein the nozzle plate further has a liquid repellent layer. 4. The liquid ejection head according to claim 3, wherein the liquid repellent layer is exposed on the surface of the nozzle plate, and the liquid repellent layer, the resin layer, and the deformation suppressing layer are laminated in this order from the surface side. The liquid ejection head according to claim 3, wherein the resin layer and the liquid repellent layer contain a negative photosensitive resin. The nozzle has a first part of the nozzle formed on the deformation suppressing layer, and a second part of the nozzle formed on a part other than the deformation suppressing layer,
The second portion of the nozzle has a smaller inner diameter than the first portion of the nozzle, and
The liquid ejection head according to claim 1, wherein the difference between the inner diameter of the first portion of the nozzle and the inner diameter of the second portion of the nozzle is 12% or less with respect to the inner diameter of the first portion of the nozzle. The contact angle of pure water on the deformation suppressing layer is less than 90°, and
The liquid ejection head according to claim 1, wherein a contact angle of pure water on the resin layer is less than 90°. The liquid ejection head according to claim 3, wherein the thickness of the deformation suppressing layer is greater than the total thickness of the liquid repellent layer and the resin layer. The liquid ejection head according to claim 3, wherein the total thickness of the liquid repellent layer and the resin layer is 10 μm or less. The liquid ejection head according to claim 1, wherein the nozzle formed in the deformation suppressing layer has at least one of a multi-stage structure and a tapered structure. The nozzle has a first part of the nozzle formed on the deformation suppressing layer, and a second part of the nozzle formed on a part other than the deformation suppressing layer,
The liquid ejection head according to claim 1, wherein the resin layer is formed so as to enter the first part of the nozzle from the second part of the nozzle. The deformation suppressing layer has a support layer having a Young's modulus of 50 GPa or more and a functional layer,
The liquid ejection head according to claim 1, wherein the functional layer has a lower reflectance than the support layer for light having a wavelength to which the resin layer is sensitive. A liquid ejection device comprising the liquid ejection head according to claim 1 . a nozzle plate provided with a discharge port for discharging liquid;
a flow path forming member provided with a pressure chamber adjacent to the nozzle plate and connected to the discharge port via a nozzle;
A liquid ejection head comprising: an energy generating element configured to generate energy for ejecting the liquid into the pressure chamber;
A method for manufacturing a liquid ejection head in which the nozzle plate includes a liquid repellent layer, a photosensitive material layer, and a deformation suppressing layer having a Young's modulus of 50 GPa or more,
A method for manufacturing a liquid ejection head, comprising the step of forming at least one of the photosensitive material layer and the liquid repellent layer using a dry film resist. 15. The method for manufacturing a liquid ejection head according to claim 14, wherein the step of joining the deformation suppressing layer with the flow path forming member is performed before the step of forming the photosensitive material layer and the liquid repellent layer. The nozzle has a first part of the nozzle formed on the deformation suppressing layer, and a second part of the nozzle formed on a part other than the deformation suppressing layer,
Liquid ejection according to claim 14, wherein the step of forming the photosensitive material layer includes the step of forming the photosensitive material layer so as to enter the first portion of the nozzle from the second portion of the nozzle. Head manufacturing method. In the step of forming at least one of the photosensitive material layer and the liquid-repellent layer with a dry film resist, the second portion of the nozzle is formed by patterning the dry film resist while peeling it from its supporting member. 15. The method for manufacturing a liquid ejection head according to item 14. 15. The method for manufacturing a liquid ejection head according to claim 14, further comprising the step of irradiating energy to the liquid repellent layer to segregate the liquid repellent components in the liquid repellent layer.

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