Liquid ejection head and method of manufacturing the same

Abstract

A liquid ejection head includes a nozzle plate at which nozzles for ejecting liquid are provided, a substrate including a piezoelectric element for generating pressure for ejecting liquid from the nozzles, and a wall member made of resin and provided between the nozzle plate and the substrate so as to form a pressure chamber communicating with the nozzles. Among a plurality of side surfaces of the wall member forming the pressure chamber, a structure for connecting at least two side surfaces is provided. A manufacturing method of a liquid ejection head is also disclosed.

Description

Technical Field

[0001] This invention relates to a liquid injection head and a method for manufacturing the liquid injection head. Background Technology

[0002] To achieve higher resolution and higher quality printing in inkjet printers, which serve as liquid jetting devices, it is necessary to manufacture high-resolution liquid jetting heads by improving the machining precision of the liquid jetting heads. Japanese Patent No. 4300565 discusses a piezoelectric liquid jetting head in which nozzles can be arranged in a highly integrated manner at low cost by using photosensitive resin as the material of the pressure chamber.

[0003] According to the liquid injection head discussed in Japanese Patent No. 4300565, nozzles are arranged in a highly integrated manner to improve processing accuracy by using photosensitive resin to form pressure chambers. However, with the increased integration of nozzles, the liquid injection frequency may decrease because the walls between adjacent pressure chambers are thinner and more prone to deformation. Summary of the Invention

[0004] The present invention generally provides a liquid jet head capable of suppressing deformation of the pressure chamber when the pressure chamber is formed of resin, and a method for manufacturing the liquid jet head.

[0005] According to one aspect of the invention, a liquid injection head includes: a nozzle plate in which a nozzle for injecting liquid is disposed; a substrate including a piezoelectric element for generating pressure for injecting liquid from the nozzle; and a wall member made of resin and disposed between the nozzle plate and the substrate to form a pressure chamber in communication with the nozzle, wherein structural members for connecting at least two side surfaces are provided on a plurality of side surfaces of the wall member forming the pressure chamber.

[0006] According to another aspect of the present invention, a method for manufacturing a liquid jet head includes: a nozzle plate in which a nozzle for jetting liquid is disposed; a substrate including a piezoelectric element for generating pressure for jetting liquid from the nozzle; and a wall member made of resin and disposed between the nozzle plate and the substrate to form a pressure chamber communicating with the nozzle, wherein structural members for connecting at least two side surfaces are provided on a plurality of side surfaces of the wall member forming the pressure chamber, the method comprising: forming a piezoelectric element on the substrate; forming the wall member on the substrate by using a photosensitive resin; and bonding the nozzle plate to the wall member, wherein forming the wall member comprises: molding a first photosensitive resin and exposing the first photosensitive resin, molding a second photosensitive resin on the first photosensitive resin and exposing the second photosensitive resin, and co-developing the first and second photosensitive resins.

[0007] Other features of the invention will become clear from the following description of embodiments with reference to the accompanying drawings.

[0008] Brief description of the attached figures

[0009] Figure 1 This is a view showing an example of a liquid injection head according to an embodiment of the present invention.

[0010] Figure 2A and 2B This is a cross-sectional view showing an example of a liquid injection head based on a comparative example. Figure 2C and 2D This is a view showing an instance of a liquid jet head in the middle of its manufacturing process, based on a comparative example.

[0011] Figure 3A and 3B This is a cross-sectional view showing an example of a liquid injection head according to an embodiment. Figure 3C and 3D This is a view showing an example of a liquid jet head according to an embodiment during its manufacturing process. Figure 3E This is a cross-sectional view showing the pressure chamber wall component of the liquid injection head according to an embodiment.

[0012] Figure 4A , 4B 4C, 4D and 4E are cross-sectional views showing examples of liquid injection heads according to embodiments.

[0013] Figure 5A This is a cross-sectional view showing an example of a liquid injection head according to an embodiment. Figure 5B It is along Figure 5A The sectional view taken by line A-A' in the middle. Figure 5C It is along Figure 5A The sectional view taken by line B-B' in the diagram. Figure 5D This is a cross-sectional view showing an example of a liquid injection head according to an embodiment. Figure 5E It is along Figure 5D The sectional view taken by line C-C' in the figure. Figure 5F It is along Figure 5D The sectional view taken by line D-D' in the middle. Figure 5G This is a cross-sectional view showing an example of a liquid injection head according to an embodiment. Figure 5H It is along Figure 5G The sectional view taken by line E-E' in the middle. Figure 5I It is along Figure 5G The sectional view taken by line F-F' in the middle.

[0014] Figure 6A , 6B 6C and 6D are cross-sectional views showing an example of a liquid injection head according to this embodiment.

[0015] Figure 7A , 7B 7C, 7D, 7E, 7F and 7G are cross-sectional views showing examples of liquid injection heads according to embodiments.

[0016] Figure 8A , 8B 8C, 8D, and 8E are views illustrating the steps in an example of a method for manufacturing a liquid jet head according to an embodiment.

[0017] Figure 9A , 9B 9C, 9D, 9E and 9F are views illustrating a step in another example of a method for manufacturing a liquid jet head according to an embodiment.

[0018] Figure 10A , 10B 10C, 10D, 10E, and 10F are views illustrating a step in another example of a method for manufacturing a liquid jet head according to an embodiment.

[0019] Figure 11A This is a view showing a process in another example of a method for manufacturing a liquid jet head according to an embodiment. Figure 11B It is along Figure 11A The sectional view taken by line A-A' in the middle. Figure 11C This is a view showing the pressure chamber wall component in another example of a method for manufacturing a liquid jet head according to an embodiment.

[0020] Figure 12A This is a view showing a process in another example of a method for manufacturing a liquid jet head according to an embodiment. Figure 12B It is along Figure 12A The sectional view taken by line A-A' in the middle.

[0021] Figure 13A This is a view showing a process in another example of a method for manufacturing a liquid jet head according to an embodiment. Figure 13B It is along Figure 13A The sectional view taken by line A-A' in the middle. Detailed Implementation

[0022] Figure 1 This is a top view showing an example of a liquid injection head according to an embodiment of the present invention, viewed from the side where the nozzle 11 is located.

[0023] Figure 1 The dashed lines in the diagram represent a portion of the internal structure not visible from the nozzle 11 side. Multiple nozzles 11 are arranged in a row, and the pressure chamber 10 (see...) Figure 2A(Each pressure chamber has a basic cuboid shape and corresponds to a nozzle 11) arranged such that the long sides of the pressure chambers 10 are adjacent to each other along the direction of their short sides. The shape of the pressure chambers 10 is not limited to a basic cuboid shape.

[0024] First, refer to the following Figures 2A to 2D The problem addressed in this embodiment is illustrated using a comparative example of a liquid injection head. Figure 2A This is a cross-sectional view along a direction parallel to the long side of the pressure chamber 10. The substrate 1 includes piezoelectric elements 2, a vibrating plate 3, and a liquid supply port 4. Each piezoelectric element 2 has a generally rectangular shape and extends along the long side of the pressure chamber 10, which has a generally cuboid shape. A pressure chamber wall component 5 is connected to the surface of the substrate 1 on which the vibrating plate 3 is disposed, and a nozzle plate 6 (on which nozzles 11 are disposed) is connected to the surface of the pressure chamber wall component 5 opposite to the surface of the pressure chamber wall component 5 connected to the substrate 1. The pressure chamber 10 is the space surrounded by the nozzle plate 6, the substrate 1, and the pressure chamber wall component 5. The pressure chamber 10 communicates with the corresponding nozzles 11. When the piezoelectric elements 2 are driven to bend the vibrating plate 3 toward the inside of the pressure chamber 10, liquid supplied from the liquid supply port 4 to the pressure chamber 10 and the nozzles 11 is ejected from the nozzles 11. By using a photosensitive material (e.g., photosensitive resin) to form the pressure chamber wall component 5, the nozzles 11 can be arranged in a highly integrated manner at low cost.

[0025] Compared to using inorganic materials to form the pressure chamber wall component 5, it is also easy to improve the machining accuracy.

[0026] Figure 2B It is along Figure 2A The sectional view taken by line C-C' in the middle. Figure 2D This is a perspective view of the pressure chamber wall component 5 as seen from the surface of the pressure chamber wall component bonded to the nozzle plate 6. Multiple pressure chambers 10 are arranged adjacent to each other along the short side direction of the pressure chamber 10, with the pressure chamber wall 50 between them. When the multiple nozzles 11 and multiple pressure chambers 10 are formed in a high-density state and the pressure chamber wall 50 is relatively thin, the pressure chamber wall 50 may be prone to deformation, such as... Figure 2B As shown. This may affect the liquid jetting.

[0027] Figure 2CThis illustrates an example of a liquid jet head manufactured according to a comparative example, showing the connection between the pressure chamber wall component 5 and the substrate 1. When the pressure chamber wall component 5, having a pressure chamber 10, is processed with resin, deformation of the pressure chamber wall 50 can occur. When using photosensitive resin, deformation of the pressure chamber wall 50 may occur during the developing, drying, and heat treatment processes, or in subsequent processes such as surface treatment, film formation, and nozzle plate 6 formation. This can lead to insufficient machining accuracy of the pressure chamber 10 of the liquid jet head and affect liquid jetting. Deformation of the pressure chamber wall 50 becomes more pronounced when the wall width of the pressure chamber wall 50 narrows and the length of the pressure chamber 10 along its long side increases. Using a resin with lower rigidity for the pressure chamber wall component 5 also contributes to the ease with which the pressure chamber wall 50 deforms.

[0028] Figures 3A to 3E An example of a liquid injection head according to this embodiment is shown. Similar to the liquid injection head described above according to the comparative example, the pressure chamber wall component 5 is formed of a photosensitive material, such as a photosensitive resin. From the viewpoint of improving processing accuracy, it is desirable to use a photosensitive resin. From the viewpoint of heat resistance, it is more desirable to use a photosensitive epoxy resin.

[0029] Figure 3A It is along Figure 1 A cross-sectional view taken along line A-A' and viewed in a direction parallel to the long side of the pressure chamber 10. Figure 3B It is along Figure 1 The sectional view taken by line B-B' in the figure.

[0030] Figure 3D This is a perspective view of the pressure chamber wall component 5 as seen from the surface of the pressure chamber wall component adhered to the nozzle plate 6. Figure 3E It is along Figure 3A The sectional view taken by line D-D' shows only the pressure chamber wall component 5.

[0031] In the liquid injection head according to this embodiment, a structural member 7 is provided for connecting at least two of the four side surfaces (pressure chamber walls 50) forming each pressure chamber 10 (each space). Figure 3B This indicates that the pressure chamber wall 50 is supported by the structural member 7. Providing the structural member 7 can suppress deformation of the pressure chamber wall component 5. This configuration makes it easier to reduce the thickness of the pressure chamber wall 50, thereby allowing the nozzles 11 to be arranged in a more integrated manner.

[0032] exist Figures 3A to 3EIn this design, structural component 7 is integrally formed with pressure chamber wall component 5. By using the same resin (same material) as the resin used for pressure chamber wall component 5 to integrally form structural component 7 with pressure chamber wall component 5, higher machining accuracy can be achieved, and the manufacturing process can be simplified. Alternatively, structural component 7 can be a different component from pressure chamber wall component 5.

[0033] Figure 3C This illustrates an example of a liquid injection head according to this embodiment during the manufacturing process, showing the state in which the pressure chamber wall component 5 is connected to the substrate 1. Figure 2C Compared to the comparative example shown, the deformation of the pressure chamber wall component 5 (pressure chamber wall 50) is suppressed by the structural member 7 that connects to the pressure chamber wall 50.

[0034] like Figures 3A to 3E As shown, preferably, the pressure chamber walls 50 between spaces are continuously connected along the short side of the pressure chamber 10 via structural members 7. In this case, structural members 7 have a higher deformation suppression effect relative to their size and are suitable for increasing the density of nozzles 11. Figure 3A and 3B As shown, the height of the pressure chamber 10 is defined as T, and the thickness of the pressure chamber wall 50 (thickness of the pressure chamber wall component 5) between adjacent pressure chambers 10 along the short side direction is defined as L. Since the pressure chamber wall component 5 is formed using a negative photosensitive material based on epoxy resin, the inventors have found that when the aspect ratio T / L > 6, the deformation of the pressure chamber wall 50 after development with the photosensitive resin is more significant. Therefore, as the ratio of T increases, the processing accuracy tends to decrease, and the incidence of large deformation of the pressure chamber wall 50 during the manufacturing process of the liquid jet head tends to be higher. Providing the structural member 7 according to this embodiment can suppress the deformation of the pressure chamber wall 50. Therefore, it is preferable to provide the structural member 7 because the effect of suppressing the decrease in processing accuracy and the effect of suppressing the deformation of the pressure chamber 10 according to this embodiment increase as the ratio of T in the aspect ratio L:T increases. The ratio of T to L preferably satisfies the relationship T / L > 1, more preferably T / L > 2, which is higher than the commonly used size ratio L:T = 1:2. Even more preferably, the ratio of T to L satisfies the relationship T / L>4, which can double the integration of nozzle 11 in a typical structure. Moreover, this embodiment can be suitably applied even when the ratio T / L>6, where deformation after development may be a significant issue.

[0035] Figures 4A to 4E Various arrangements of the structural member 7 in the liquid injection head according to this embodiment are shown, and the effect of suppressing deformation of the pressure chamber wall 50 by using the structural member 7 can be achieved in any of the shown configurations. Figures 4A to 4E As shown, each nozzle 11 can have a multi-stage structure.

[0036] like Figure 4A As shown, the first surface 100 of each pressure chamber 10 contacts the corresponding vibrating plate 3, and the second surface 200 of each pressure chamber 10 contacts the nozzle plate 6. The first surface 100 is the surface of each pressure chamber 10 on the side where the piezoelectric element 2 is located, while the second surface 200 is the surface of each pressure chamber 10 on the side where the nozzle plate 6 is located. Figure 4A In this configuration, structural member 7 is arranged to contact the first surface 100. For example... Figure 4A As shown, when the structural member 7 is arranged to face the piezoelectric element 2 via the vibrating plate 3, although the deformation of the pressure chamber wall 50 can be suppressed when the piezoelectric element 2 is driven, the structural member 7 will affect the operation of the vibrating plate 3. Therefore, when the structural member 7 is arranged on the first surface 100, it is preferable that the structural member 7 is arranged at a position offset from the piezoelectric element 2.

[0037] exist Figure 4B In this configuration, the structural member 7 is positioned away from the first surface 100 and the second surface 200. In this case, when the piezoelectric element 2 is driven, the operation of the vibrating plate 3 is less affected, and the effect of suppressing deformation of the pressure chamber wall 50 is also achieved. Therefore, this configuration is preferred compared to one where the structural member 7 is positioned on the first surface 100.

[0038] exist Figure 4C In this configuration, structural member 7 is arranged on the first surface 100 at positions corresponding to both ends of the piezoelectric element 2 along the long side of the pressure chamber 10. Because structural member 7 is positioned offset from the piezoelectric element 2, when the piezoelectric element 2 is driven, deformation of the pressure chamber wall 50 can be suppressed without significantly affecting the operation of the vibrating plate 3. Furthermore, because structural member 7 is positioned at both ends of the piezoelectric element 2, the pressure of the liquid can be concentrated on the nozzle 11. Figure 4D In this configuration, structural member 7 is arranged to face both ends of piezoelectric element 2 at a position away from the first surface 100 and the second surface 200. Figure 4E In this configuration, structural member 7 is arranged on the second surface 200 at both ends facing the piezoelectric element 2. For example... Figures 4C to 4E As shown, by arranging the structural member 7 along the long side at both ends of the piezoelectric element 2 in a planar view perpendicular to the substrate 1, the impact on the operation of the piezoelectric element 2 and the vibrating plate 3 can be reduced, while simultaneously achieving the effect of suppressing deformation of the pressure chamber wall 50. This configuration is even more preferred because it also achieves the effect of concentrating the pressure of the liquid on the nozzle 11.

[0039] Figures 5A to 5I This illustrates another construction example of the liquid injection head according to this embodiment. For example... Figures 5A to 5CAs shown, deformation can be suppressed by using structural member 7 to reinforce the pressure chamber wall 50 along the long side. Figure 5A In the context of Figure 3A A sectional view at the position corresponding to line D-D' in the diagram. Figure 5B It is along Figure 5A The sectional view taken by line A-A' in the middle. Figure 5C It is along Figure 5A The sectional view taken by line B-B' in the figure.

[0040] like Figures 5D to 5F As shown, structural member 7 reinforces the pressure chamber wall 50 along its long side and is also continuously connected to the pressure chamber wall 50 along its short side. This construction increases the effect of suppressing deformation of the pressure chamber wall 50. Figure 5D In the context of Figure 3A A sectional view at the position corresponding to line D-D' in the diagram. Figure 5E It is along Figure 5D The sectional view taken by line C-C' in the middle. Figure 5F It is along Figure 5D The cross-sectional view is taken along line D-D'. In the plan view perpendicular to the substrate 1, the area of ​​the vibrating plate 3 corresponding to each pressure chamber 10 and each piezoelectric element 2 is defined as the effective vibration area. Moreover, the length of the effective vibration area along the long side is defined as R, and the length of the portion along the long side that does not overlap with the structural member 7 in length R is defined as S. Considering the effect of suppressing deformation of the pressure chamber wall 50 and the efficiency of transmitting the liquid injection pressure to the nozzle 11, the ratio of S to R is preferably 30% or more and 90% or less, more preferably 50% or more and 70% or less.

[0041] like Figure 5G to 5I As shown, the length Q of the portion without structural member 7 can be included in the length P of the pressure chamber 10 along its long side. Figure 5G In the context of Figure 3A A sectional view at the position corresponding to line D-D' in the diagram. Figure 5H It is along Figure 5G The sectional view taken by line E-E' in the middle, and Figure 5I It is along Figure 5GThe cross-sectional view is taken along line F-F'. Because the pressure applied to the liquid is partially released to the outside through the nozzles 11, the effect of suppressing deformation of the pressure chamber wall 50 can be increased by arranging the portion without the structural member 7 with length Q adjacent to each nozzle 11. Moreover, the design constraints caused by the structural member 7 are reduced, thereby increasing the design freedom of the nozzles 11. The effect of suppressing deformation of the pressure chamber wall 50 increases as the ratio of Q to P decreases. The ratio of Q to P is preferably 90% or less, more preferably 70% or less. Even more preferably, the ratio of Q to P is 50% or less. Furthermore, in the plan view along the direction perpendicular to the substrate 1, the ratio of the overlapping portions of the structural member 7 and each pressure chamber 10 preferably decreases from the liquid supply port 4 side toward the nozzle 11 side. In this case, the ability to concentrate the injection pressure (which is applied to the liquid from the piezoelectric element 2) on the nozzles 11 can be increased. This effect increases as the ratio of the length of the structural member 7 to the length of the pressure chamber 10 (space) along the long side increases. The proportion is preferably 20% or more, more preferably 30% or more. Even more preferably, the proportion is 40% or more.

[0042] Figures 6A to 6D This illustrates another example of a liquid injection head according to this embodiment. For example... Figure 6A As shown, even when the nozzle 11 is at a high height in the direction perpendicular to the substrate 1, the effect of the structural member 7 can be obtained.

[0043] Figure 6B This indicates that the structural member 7 is integrated with the pressure chamber wall component 5. In this case, the effects resulting from providing the structural member 7 can be obtained. The structural member 7 is a component that strengthens the pressure chamber wall 50. When the structural member 7 is integrated with the pressure chamber wall 50, the portion of the pressure chamber wall component 5 facing each vibrating plate 3 is considered the structural member 7.

[0044] Figure 6C This diagram illustrates a liquid jet head comprising structural member 7 and structural member 70, which also functions as a damper with liquid vibration suppression effects to prevent crosstalk. By adding functions to structural member 7 beyond supporting the pressure chamber wall 50, the number of components can be reduced, and the liquid jet head can be manufactured more easily.

[0045] Figure 6D The diagram illustrates the construction of a liquid injection head, which includes: a structural member 7; a nozzle plate 6 formed by multiple components; and a pressure chamber wall component 5, in which a liquid supply port 4 is disposed. In this construction, the structural member 7 serves to support the pressure chamber wall 50 and provides the effect of concentrating the pressure applied to the liquid from the piezoelectric element 2 onto the nozzle 11.

[0046] Even when the liquid jet head circulates the liquid internally, the effects according to this embodiment can be achieved, such as... Figures 7A to 7G As shown. The substrate 1 includes a liquid supply port 4a for supplying liquid to each pressure chamber 10 and a liquid outlet 4b for allowing liquid to flow out of each pressure chamber 10. Figures 7A to 7G In the examples of liquid injection heads shown according to this embodiment, the structural member 7 is continuously connected to the pressure chamber wall 50 along the short side direction.

[0047] exist Figure 7A In this configuration, structural member 7 is arranged on the first surface 100 at positions corresponding to both ends of the piezoelectric element 2. Figure 7B In this configuration, structural member 7 is arranged on the second surface 200 at positions corresponding to both ends of the piezoelectric element 2. Similarly, structural member 7 has the effect of suppressing deformation of the pressure chamber wall 50 in both of the aforementioned configurations, but... Figure 7A The configuration shown is preferred because the liquid circulates more efficiently within each nozzle 11.

[0048] exist Figure 7C In the liquid circulation direction, structural member 7 is arranged on the second surface 200 at a position corresponding to the end of each piezoelectric element 2 closer to the liquid supply port 4a than the nozzle 11, and on the first surface 100 at a position corresponding to the end of each piezoelectric element 2 closer to the liquid outlet 4b than the nozzle 11. This configuration promotes liquid circulation within the nozzle 11. The arrangement of each nozzle 11 can be adjusted between the front structural member 7 and the rear structural member 7. Figure 7D In addition to Figure 7C In addition to the configuration shown, the liquid injection head also includes another structural member 7, which contacts the first surface 100 at a position closer to the liquid supply port 4a than the structural member 7 (which contacts the second surface 200 at a position closer to the liquid supply port 4a than the nozzle 11). In other words, along the liquid circulation direction, the liquid injection head includes a structural member 7 that contacts the first surface 100 at a position closer to the liquid supply port 4a than the nozzle 11, and a structural member 7 that contacts the second surface 200 at a position closer to the liquid supply port 4a than the nozzle 11. By adjusting the arrangement of the structural members 7, the effect of efficiently adjusting the liquid resistance on the liquid supply port 4a side can also be achieved. Figure 7E In this configuration, the nozzle 11 extends partially beyond the structural member 7 on the liquid outlet 4b side towards the liquid outlet 4b. This design allows for improved efficiency in liquid circulation within the nozzle 11. Figure 7FIn this design, the nozzle 11 extends partially beyond the liquid outlet 4b via the structural member 7. This configuration allows for improved efficiency in liquid circulation within the nozzle 11. Furthermore, Figure 7F The liquid injection head includes a structure 7 that contacts the first surface 100 at a position behind the liquid supply port 4a and a structure 7 that contacts the second surface 200 at a position facing the liquid supply port 4a. This configuration allows for adjustment of liquid resistance in areas away from the nozzle 11.

[0049] Figures 8A to 8E An example of a method for manufacturing a liquid injection head according to this embodiment is shown. The various steps described below can be performed using known techniques.

[0050] like Figure 8A As shown, a substrate 1 including a piezoelectric element 2 is fabricated. Figure 8A In the substrate 1, there are also a vibrating plate 3, a liquid supply port 4a and a liquid outlet 4b.

[0051] Next, as Figure 8B As shown, a mold component 8 is formed on the substrate 1. A photosensitive material primarily comprising phenolic varnish resin or acrylic resin can be used as the material for the mold component 8. Alternatively, cyclized rubber can be used. To use the photosensitive material to form the mold component 8, the exposure conditions vary depending on the area. This allows for the formation of portions penetrating to the first surface 100 of the substrate 1 and portions not penetrating to the first surface 100 during the development process. The portions not penetrating to the first surface 100 are the portions corresponding to the structural member 7 when forming the pressure chamber wall component 5.

[0052] Next, as Figure 8C As shown, the pressure chamber wall component 5 is formed on the mold component 8 using a photosensitive resin. The pressure chamber wall component 5 can be formed using methods such as spin coating, slot coating, spraying, nanoimprinting, dipping, or dry film formation. Subsequently, the nozzle 11 is formed by exposure and development using a mask. When the pressure chamber wall component 5 is formed on the mold component 8, the flatness of the pressure chamber wall component 5 may be degraded due to the roughness of the mold component 8. In this case, additional planarization treatment, such as polishing, can be performed after the formation of the pressure chamber wall component 5.

[0053] Next, as Figure 8D As shown, mold component 8 is removed. Dry or wet processing can be used to remove mold component 8, but wet processing is preferred because it easily increases the selection ratio with the pressure chamber wall component 5. The pressure chamber wall component 5, including structural member 7, is formed by removing mold component 8. Figures 8A to 8EIn the liquid injection head shown, the nozzle plate 6 and the pressure chamber wall component 5 are integrated with each other.

[0054] like Figure 8E As shown, a functional membrane 9 can also be formed on the pressure chamber wall component 5 and the structural component 7. The functional membrane 9 can be formed on a portion different from the pressure chamber wall component 5 and the structural component 7.

[0055] From the viewpoint of liquid injection, it is preferable to use a membrane that can enhance the strength of the pressure chamber wall component 5 as the functional membrane 9. The functional membrane 9 can also serve as a protective membrane to prevent damage during the manufacturing process and improve resistance to the liquid contacted by the liquid injection head, or as a membrane to adjust the affinity for the liquid. Furthermore, the functional membrane 9 can be a laminated membrane comprising membranes having the aforementioned functions. It is preferable to use a material with a Young's modulus of 50 GPa or higher as the material of the functional membrane 9 to enhance the strength of the pressure chamber wall component 5. Generally, the Young's modulus of resin is lower than that of metal. It has been reported that epoxy resin has a Young's modulus of approximately 2 GPa, and even resins with higher Young's moduli have values ​​less than 5 GPa. Therefore, when the Young's modulus of the functional membrane 9 is 50 GPa, this value is greater than or equal to ten times the value of resins with higher Young's moduli. For example, materials such as stainless steel, nickel (Ni), iridium (Ir), tantalum (Ta), tungsten (W), molybdenum (Mo), chromium (Cr), cobalt (Co), iron (Fe), ruthenium (Ru), silicon carbide (SiC), titanium carbide (TiC), tungsten carbide (WC), boron carbide (B4C), zirconium oxide (ZrO2), aluminum oxide (Al2O3), tantalum oxide (Ta2O5), aluminum nitride (AlN), silicon nitride (Si3N4), titanium nitride (TiN), and diamond can be used for functional films.

[0056] For example, film formation methods such as physical vapor deposition (PVD), atomic layer deposition (ALD), or chemical vacuum deposition (CVD) can be used to form the functional film 9. In the PVD method, sputtering, vacuum deposition, molecular beam epitaxy, laser deposition, electron beam evaporation, etc., can be used. In the CVD method, various methods using heat, plasma, electromagnetic waves, and catalysts can be used in combination. Alternatively, wet processing, such as electroplating, can be used. The functional film 9 can also be formed by using the above-described film formation methods in combination. After forming the functional film 9, processing using heat, electromagnetic waves, electron beams, or plasma can be performed. Wet processing carries the risk of defects due to bubble entrainment, etc. Therefore, considering the formation of a film on a microstructure (e.g., the pressure chamber wall component 5 according to this embodiment), even though defects can be reduced by repeated film formation and cleaning, wet processing is not preferred from the viewpoint of film thickness control. Therefore, it is preferable to use film formation methods that are less prone to defects, such as PVD, CVD, or ALD methods. From the viewpoint of coatability, CVD methods are preferred, and even more preferred is ALD methods, which offer excellent step-size coverage on the microstructure. When the functional film 9 is to be selectively formed on the surface of the nozzle plate 6, PVD methods, which are highly directional film formation methods, are preferred. In particular, PVD methods (e.g., vacuum deposition, molecular beam epitaxy, laser deposition, or electron beam evaporation) that can easily increase the vacuum level during film formation are more preferred.

[0057] Figures 9A to 9F This illustrates another example of a method for manufacturing a liquid injection head according to this embodiment. The various steps described below can be performed using known techniques.

[0058] like Figure 9A As shown, a substrate 1 including a piezoelectric element 2 is fabricated. Figure 9A In the substrate 1, there are also a vibrating plate 3, a liquid supply port 4a and a liquid outlet 4b.

[0059] Next, as Figure 9B As shown, a first pressure chamber wall component 51 is formed on a substrate 1 using a photosensitive resin. A latent image of a portion 151 corresponding to the pressure chamber wall component 5 is formed by exposure using a mask.

[0060] Next, as Figure 9CAs shown, a second pressure chamber wall component 52 is formed on a first pressure chamber wall component 51 using a photosensitive resin. A latent image of a portion 152 corresponding to the pressure chamber wall component 5 is formed by exposure using a mask. When forming the second pressure chamber wall component 52, the photosensitive resin or exposure conditions are selected using known techniques, which can protect the first pressure chamber wall component 51 from exposure during the formation of the second pressure chamber wall component 52.

[0061] Subsequently, as Figure 9D As shown, a first nozzle plate component 61 is formed. A latent image of the portion 161 corresponding to the nozzle plate 6 is formed by exposure using a mask. When forming the first nozzle plate component 61, a photosensitive resin or exposure condition is selected using known techniques, which can protect the pressure chamber wall component 5 from exposure.

[0062] As described above, by forming a latent image using photolithography to create the pressure chamber wall component 5 and the first nozzle plate component 61, the flatness and thickness accuracy of the components to be formed can be easily improved compared to using the mold component 8. The pressure chamber wall component 5 and the structural component 7 can be constructed by integrally forming the first pressure chamber wall component 51 and the second pressure chamber wall component 52 as a single layer and by locally changing the exposure conditions. However, in this case, the processing accuracy along the height direction may deteriorate due to changes in the exposure conditions. Therefore, as described in this embodiment, by using two or more layers of photosensitive resin to form the pressure chamber wall component 5, the processing accuracy of the structural component 7 can be easily improved.

[0063] Subsequently, as Figure 9E As shown, a second nozzle plate component 62 is formed. A latent image of the portion 162 corresponding to the nozzle plate 6 is formed by exposure using a mask. When forming the second nozzle plate component 62, a photosensitive resin or exposure condition is selected using known techniques, which can protect the pressure chamber wall component 5 and the first nozzle plate component 61 from exposure.

[0064] Next, as Figure 9F As shown, multiple layers are developed together to form the pressure chamber wall component 5, the nozzle plate 6, and the structural component 7. As described above, the functional membrane 9 can be formed on the pressure chamber wall component 5 and the structural component 7.

[0065] Figures 10A to 10F This illustrates another example of a method for manufacturing a liquid injection head according to this embodiment. The various steps described below can be performed using known techniques.

[0066] like Figure 10A As shown, a substrate 1 including a piezoelectric element 2 is fabricated. Figure 10A In the substrate 1, there are also a vibrating plate 3, a liquid supply port 4a and a liquid outlet 4b.

[0067] Next, as Figure 10B As shown, a first pressure chamber wall component 51 is formed on a substrate 1 using a photosensitive resin. A latent image of a portion 151 corresponding to the pressure chamber wall component 5 is formed by exposure using a mask.

[0068] Next, as Figure 10C As shown, a second pressure chamber wall component 52 is formed. A latent image of the portion 152 corresponding to the pressure chamber wall component 5 is formed by exposure using a mask. When forming the second pressure chamber wall component 52, a photosensitive resin or exposure condition is selected using known techniques, which can protect the first pressure chamber wall component 51 from exposure during the formation of the second pressure chamber wall component 52.

[0069] Next, as Figure 10D As shown, multiple layers are developed together to form the pressure chamber 10 and the structural component 7.

[0070] Next, as Figure 10E As shown, the nozzle plate 6 is bonded to the pressure chamber wall component 5 using adhesive 20. At this time, as... Figure 10E As shown, a recess 30 can be formed on at least one of the pressure chamber wall component 5 and the nozzle plate 6. The recess 30 can serve as an adhesive storage hole to prevent the adhesive 20 from being extruded. By forming the recess 30 on the pressure chamber wall component 5 made of photosensitive resin, the dimensional accuracy of the adhesive storage hole can be improved. The recess 30 can be formed in a known shape, such as a combination of circles, ellipses, squares, rectangles, and triangles, or have a hole or groove with a shape surrounded by curves.

[0071] Next, as Figure 10F As shown, nozzle 11 is formed and penetrates nozzle plate 6. As described above, functional membrane 9 can be formed on pressure chamber wall component 5 and structural component 7.

[0072] The following will refer to Figures 11A to 13B Another example of a method for manufacturing a liquid injection head according to this embodiment is presented. The various steps described below can be performed using known techniques.

[0073] First, such as Figure 11A As shown, a pressure chamber wall component 5, including a first pressure chamber wall component 51 and a second pressure chamber wall component 52, is formed on a substrate 1 including a piezoelectric element 2, a vibrating plate 3, a liquid supply port 4a, and a liquid outlet 4b. It can be similar to... Figures 10A to 10D The process shown forms pressure chamber wall component 5. Figure 11B It is along Figure 11A The sectional view taken by line A-A' in the middle. Figure 11C This is a plan view of the pressure chamber wall component 5 as seen from the side of the second pressure chamber wall component 52. (See attached image.) Figure 11B and 11C As shown, multiple pressure chambers 10 are arranged adjacent to each other along the short side direction, and recessed portions 30 are formed on the walls 50 of each pressure chamber.

[0074] Next, as Figure 12A and 12B As shown, a functional membrane 9 is formed on the surface of the pressure chamber wall component 5 and the structural component 7. Figure 12A It is a cross-sectional view along a direction parallel to the long side of the pressure chamber 10. Figure 12B It is along Figure 12A The cross-sectional view is taken along line A-A'. By also forming the functional membrane 9 on the wall surface of the recessed portion 30, the strength of the pressure chamber wall component 5 can be enhanced. Then, in the process of bonding the nozzle plate 6 to the pressure chamber wall component 5 and performing the processing, or in the process of mounting the cut individual chips, there are cases where plasma treatment is used to perform processing or cleaning processes. In these cases, the functional membrane 9 can act as a membrane to protect the pressure chamber wall component 5 from damage caused by plasma treatment.

[0075] Next, as Figure 13A As shown, the nozzle plate 6 is bonded to the pressure chamber wall component 5 using adhesive 20. Figure 13A It is a cross-sectional view along a direction parallel to the long side of the pressure chamber 10. Figure 13B It is along Figure 13A The sectional view taken by line A-A' in the middle.

[0076] In this embodiment, ink is supplied to the liquid ejector head from an ink tank disposed outside the liquid ejector head, and inside the liquid ejector head, ink is further supplied to the pressure chamber 10 and the nozzle 11 through the liquid supply port 4a. The liquid ejector head according to this embodiment also includes a drive circuit (not shown) on the substrate 1, which applies a drive electrical signal to drive each piezoelectric element 2. When the electrical signal is applied from the drive circuit to each piezoelectric element 2, the piezoelectric effect of the piezoelectric element 2 causes the vibrating plate 3 to bend towards the inside of the pressure chamber 10, thereby causing liquid to be ejected from the nozzle 11.

[0077] In the liquid jet head according to this embodiment, the nozzles 11 can be arranged in a highly integrated manner. Depending on the application purpose of the liquid jet head, it may be desirable to jet as many droplets as possible at once. In this case, it is effective to simultaneously drive two or more piezoelectric elements 2 in the liquid jet head according to this embodiment. In this case, integrated circuits are typically used, but the influence of the processing temperature when forming the piezoelectric elements 2 may cause manufacturing problems, such as great difficulty in building the piezoelectric elements 2 and the integrated circuit on the same substrate 1, or increased costs. Therefore, it is preferable to arrange a common wiring for inputting driving electrical signals to two or more piezoelectric elements 2. Preferably, a common wiring is arranged to connect two or more piezoelectric elements 2. More preferably, the number of piezoelectric elements 2 connected to one common wiring is 10 or more. Even more preferably, the number of piezoelectric elements 2 connected to one common wiring is 100 or more, and even more preferably, the number is 1000 or more. In this case, the effect of reducing the number of pads used for inputting electrical signals can also be obtained.

[0078] pass Figures 9A to 9F The process shown forms a product with Figure 4E The liquid jet head with the structure shown.

[0079] A substrate 1 is formed comprising a piezoelectric element 2, a drive circuit (not shown), a liquid supply port 4, and a vibrating plate 3. The piezoelectric element 2 comprises piezoelectric zirconium titanate (PZT), and the vibrating plate 3 comprises silicon as a substrate.

[0080] Pressure chamber wall component 5 is formed on the first surface 100 side of substrate 1 using two layers of photosensitive resin. First, a dry film of negative photosensitive epoxy resin with a thickness of 40 μm, serving as the first pressure chamber wall component 51, is transferred onto the first surface 100. Then, a latent image corresponding to the portion of pressure chamber 10 is formed by performing post-exposure baking (PEB) after exposure using a photomask. Subsequently, a dry film of negative photosensitive epoxy resin with a thickness of 20 μm, serving as the second pressure chamber wall component 52, is transferred onto the first pressure chamber wall component 51. Then, a latent image corresponding to the portion of pressure chamber 10 and structural component 7 is formed by performing PEB after exposure using a photomask. Then, the first pressure chamber wall component 51 and the second pressure chamber wall component 52 are co-developed using an organic solvent. Furthermore, a heat treatment to accelerate the curing of the epoxy resin is performed. The width of each pressure chamber wall 50 between pressure chambers 10 is 10 μm, the width of each pressure chamber 10 along its short side is 32.5 μm, and the width of each pressure chamber 10 along its long side is 1000 μm, and the pressure chambers 10 are formed with a pitch of 42.5 μm. Structural members 7 are formed at both ends along the long side using a second pressure chamber wall member 52. The height of the structural member 7 is 20 μm, defined by the film thickness of the second pressure chamber wall member 52, and the width of the structural member 7 is 40 μm. As a functional film 9, a film with a thickness of 0.5 μm made of Al2O3 is formed on the pressure chamber wall member 5 using the ALD method, and a film with a thickness of 0.5 μm made of Ta2O5 is further formed on the pressure chamber wall member 5.

[0081] Next, adhesive 20 (which is a film-type thermosetting epoxy adhesive) is transferred to the pressure chamber wall component 5, and nozzle plate 6 (a portion of nozzle 11 is machined on nozzle plate 6) is bonded to the pressure chamber wall component 5. Silicon is used for nozzle plate 6. After a mask pattern using photoresist is formed on nozzle plate 6, a liquid injection head is formed by using dry etching to allow nozzle 11 to penetrate nozzle plate 6.

[0082] As a comparative example, a liquid jet head without structural member 7 was formed. Apart from structural member 7, the liquid jet head was formed using a method similar to that used for the liquid jet head according to this embodiment. The liquid jet head according to this embodiment was compared with the liquid jet head according to the comparative example, and the comparison results showed that the dimensional accuracy of the pressure chamber wall 50 in the liquid jet head according to this embodiment was higher than that in the liquid jet head according to the comparative example, and a higher liquid jet frequency was obtained in the liquid jet head according to this embodiment compared to the liquid jet head according to the comparative example.

[0083] As a result of careful research, the inventors of this invention have discovered that when photosensitive resin is used to form the walls of the pressure chamber, a decrease in the liquid injection frequency can be suppressed by constructing a structure for supporting at least two sidewalls of the pressure chamber. According to this embodiment, a liquid injection head capable of suppressing deformation of the pressure chamber when the pressure chamber is formed of resin, and a method for manufacturing the liquid injection head, can be provided.

[0084] While the invention has been described with reference to embodiments, it should be understood that the invention is not limited to the disclosed embodiments. The scope of the appended claims should be accorded the broadest interpretation to cover all such modifications and equivalent structures and functions.

Claims

1. A liquid injection head, comprising: A nozzle plate, wherein a nozzle for spraying liquid is disposed at the nozzle plate; A substrate, the substrate including a piezoelectric element for generating pressure for ejecting liquid from the nozzle; A wall component, made of resin, is disposed between the nozzle plate and the substrate to form a pressure chamber communicating with the nozzle. The pressure chamber is the space surrounded by the nozzle plate, the substrate, and the wall component. The invention includes a structural member for connecting at least two of the plurality of side surfaces of the wall component forming the pressure chamber, the height of the structural member being less than the height of the pressure chamber. The liquid injection head includes a plurality of pressure chambers, each pressure chamber having a generally cuboid shape and arranged such that the plurality of pressure chambers are adjacent to each other along their short sides, and the wall components are located between adjacent pressure chambers. Where the height of the plurality of pressure chambers is limited to T, and the thickness of the wall component is limited to L, the ratio of T to L satisfies the relationship T / L>6. The structural member is continuously connected to the side surface of the wall component between adjacent pressure chambers along the short side direction of the plurality of pressure chambers.

2. The liquid injection head according to claim 1, wherein, The structural member is integrally formed with the wall component by using the same material as the wall component.

3. The liquid injection head according to claim 1, in, Each of the nozzles corresponds to one of the multiple pressure chambers.

4. The liquid injection head according to claim 1, wherein, In a plan view along a direction perpendicular to the substrate, the structural members are arranged at both ends of the piezoelectric element along its long side, and the piezoelectric element has a rectangular shape.

5. The liquid injection head according to claim 1, further comprising: A vibrating plate between the piezoelectric element and the pressure chamber The effective vibration area of ​​the vibrating plate corresponds to the pressure chamber and the piezoelectric element. In a plan view along a direction perpendicular to the substrate, the length of the portion of the long side of the effective vibration area that does not overlap with the structural member is more than 30% and less than 90% of the total length of the long side of the effective vibration area.

6. The liquid injection head according to claim 1, wherein, In a plan view along a direction perpendicular to the substrate, the ratio of the length of the portion of the pressure chamber without the structural member along the long side to the length of the pressure chamber along the long side is 90% or less.

7. The liquid injection head according to claim 1, in, The substrate includes a liquid supply port for supplying liquid to the pressure chamber. In a plan view perpendicular to the substrate, the ratio of the overlapping portions of the structural member and the pressure chamber decreases from the liquid supply port side toward the nozzle side. Wherein, the length of the structural member along the long side of the pressure chamber is more than 20% of the length of the pressure chamber along the long side.

8. The liquid injection head according to claim 1, wherein, The substrate includes a liquid supply port for supplying liquid to a pressure chamber and a liquid outlet for allowing liquid to flow out of the pressure chamber to circulate the liquid.

9. The liquid injection head according to claim 8, in, Along a direction perpendicular to the substrate, the first surface of the pressure chamber is located on the piezoelectric element side, and the second surface of the pressure chamber is located on the nozzle plate side. In the plan view perpendicular to the substrate, structural members serving as the first structural member and structural members serving as the second structural member are respectively arranged at both ends of the piezoelectric element along its long side. In this configuration, along the direction of liquid circulation, a first structural member is disposed on a first surface at a position closer to the liquid supply port than the nozzle, and a second structural member is disposed on a second surface.

10. The liquid injection head according to claim 9, in, Along a direction perpendicular to the substrate, the first surface of the pressure chamber is located on the piezoelectric element side. Wherein, along the liquid circulation direction, the structural member is arranged on the first surface on the liquid outlet side, and The nozzle extends partially toward the liquid outlet side beyond the structural member arranged on the liquid outlet side.

11. The liquid injection head according to claim 1, wherein, The wall components and the structural members are covered with a functional membrane made of a material with a Young's modulus of 50 GPa or higher.

12. The liquid injection head according to claim 1, wherein, The wall component is formed of two or more layers of resin.

13. The liquid injection head according to claim 1, wherein, The nozzle plate and the wall component are integrated.

14. The liquid injection head according to claim 1, in, The wall component and the nozzle plate are bonded to each other by an adhesive, and at least one of the wall component or the nozzle plate has a recessed portion for storing the adhesive.

15. The liquid injection head according to claim 14, wherein, The recessed portion is covered with a functional membrane made of a material with a Young's modulus of 50 GPa or higher.

16. The liquid injection head according to claim 1, further comprising: A driving circuit is configured to apply a driving electrical signal to drive the piezoelectric element. The driving circuit includes a common wiring for inputting driving electrical signals to two or more of the piezoelectric elements.

17. A method for manufacturing the liquid injection head according to claim 1, the method comprising: A piezoelectric element is formed on the substrate; A wall component is formed on the substrate by using a photosensitive resin; as well as The nozzle plate is bonded to the wall component. The wall component includes: Molding the first photosensitive resin and exposing the first photosensitive resin to light; Molding a second photosensitive resin onto a first photosensitive resin and exposing the second photosensitive resin to light; and The first and second photosensitive resins are developed together.

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