JP7192460B2 - Liquid ejecting head and liquid ejecting device - Google Patents

Description

The present invention relates to a liquid ejecting head and a liquid ejecting apparatus.

For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2002-100001, a liquid jet head is known that jets liquid in a pressure chamber from a nozzle by vibrating a vibration plate that forms part of the wall surface of the pressure chamber using a piezoelectric element.

JP 2017-80946 A

In the liquid ejecting head, in general, from the viewpoint of efficiently ejecting the liquid from the nozzles, the pressure in the pressure chamber caused by the piezoelectric element increases toward the center in the longitudinal direction of the pressure chamber. Therefore, the reaction force that the diaphragm receives from the liquid in the pressure chamber increases toward the center in the longitudinal direction of the diaphragm. In the liquid jet head disclosed in Patent Document 1, no consideration is given to the influence of the above-described reaction force on the diaphragm, so that the central portion of the diaphragm in the longitudinal direction is excessively deformed and damaged by the above-described reaction force. there is a possibility. In recent years, the width of the vibrating plate has become narrower as the pitch of the nozzles has become narrower.

In order to solve the above problems, a liquid jet head according to a preferred aspect of the present invention includes: a vibration plate forming a part of a wall surface of a pressure chamber containing liquid; a piezoelectric element for vibrating the vibration plate; a reinforcing film disposed on the surface of the diaphragm on the side of the pressure chamber, wherein the vibration area in the area of the diaphragm where the piezoelectric element vibrates is viewed from the thickness direction of the diaphragm. The reinforcement film has a longitudinal shape in a plan view, and is arranged at a position closer to the center of the vibration region in the longitudinal direction than the first portion of the first film thickness and the first portion. and a second portion having a second thickness greater than the thickness.

A liquid jet head according to another preferred aspect of the present invention includes a vibration plate forming a part of a wall surface of a pressure chamber containing liquid, a piezoelectric element for vibrating the vibration plate, and the pressure chamber of the vibration plate. and a reinforcing film disposed on the side surface of the vibration plate, and the vibration region of the vibration plate, which is vibrated by the piezoelectric element, has a longitudinal shape in plan view from the thickness direction of the vibration plate. None, the vibration region includes a first region where the reinforcing film is not arranged, and a second region which is located closer to the center of the vibration region in the longitudinal direction than the first region and where the reinforcing film is arranged. ,including.

1 is a configuration diagram schematically showing a liquid ejecting apparatus according to a first embodiment; FIG. 1 is an exploded perspective view of a liquid jet head according to a first embodiment; FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2; FIG. 3 is a plan view showing a vibration plate of the liquid jet head according to the first embodiment; FIG. FIG. 5 is a cross-sectional view taken along line VV of FIG. 4; 5 is a cross-sectional view taken along line VI-VI of FIG. 4; FIG. FIG. 5 is a cross-sectional view taken along line VII-VII of FIG. 4; FIG. 4 is a diagram showing the relationship between the thickness of the reinforcement film and the first-order natural vibration mode of the vibration region in the first embodiment; 4 is a flow chart illustrating the flow of a manufacturing process for pressure chambers. It is sectional drawing which shows a mask formation process. It is sectional drawing which shows an etching process. It is sectional drawing which shows a mask removal process. It is sectional drawing which shows a corrosion-resistant film formation process. It is sectional drawing which shows a reinforcement film formation process. FIG. 4 is a cross-sectional view showing a first step of a reinforcing film forming step; FIG. 4 is a cross-sectional view showing a second step of the reinforcing film forming step; FIG. 5 is a cross-sectional view showing pressure chambers in a second embodiment; FIG. 11 is a cross-sectional view showing a pressure chamber in a third embodiment; It is a longitudinal section showing a pressure chamber in a fourth embodiment. FIG. 12 is a diagram showing the relationship between the thickness of the reinforcement film and the first-order natural vibration mode of the vibration region in the fourth embodiment; FIG. 12 is a diagram showing the relationship between the thickness of the reinforcement film and the secondary natural vibration mode of the vibration region in the fifth embodiment; FIG. 12 is a diagram showing the relationship between the thickness of the reinforcement film and the 3rd natural vibration mode of the vibration region in the sixth embodiment.

1. First Embodiment 1-1. Overall Configuration of Liquid Ejecting Apparatus FIG. 1 is a configuration diagram schematically showing a liquid ejecting apparatus 100 according to a first embodiment. A liquid ejecting apparatus 100 according to the first embodiment is an inkjet printing apparatus that ejects ink, which is an example of liquid, onto a medium 12 . The medium 12 is typically printing paper, but any material, such as resin film or cloth, can be used as the medium 12 to be printed. As illustrated in FIG. 1, a liquid container 14 that stores ink is installed in the liquid ejecting apparatus 100 . For example, a cartridge detachable from the liquid ejecting apparatus 100, a bag-shaped ink pack formed of a flexible film, or an ink tank capable of replenishing ink is used as the liquid container 14. FIG.

As illustrated in FIG. 1, the liquid ejecting apparatus 100 includes a control unit 20, a transport mechanism 22, a moving mechanism 24, and a liquid ejecting head . The control unit 20 includes a processing circuit such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array) and a memory circuit such as a semiconductor memory, and controls each element of the liquid ejecting apparatus 100 in an integrated manner. The transport mechanism 22 transports the medium 12 in the Y direction under the control of the control unit 20 .

The moving mechanism 24 reciprocates the liquid jet head 26 in the X direction under the control of the control unit 20 . The X direction is the direction that intersects the Y direction in which the medium 12 is transported, and is typically orthogonal to the Y direction. The moving mechanism 24 of the first embodiment includes a carriage 242, which is a substantially box-shaped carrier that houses the liquid jet head 26, and a carrier belt 244 to which the carriage 242 is fixed. A configuration in which a plurality of liquid jet heads 26 are mounted on the carriage 242 or a configuration in which the liquid container 14 is mounted on the carriage 242 together with the liquid jet heads 26 may also be employed.

The liquid ejecting head 26 ejects ink supplied from the liquid container 14 onto the medium 12 from a plurality of nozzles under the control of the control unit 20 . A desired image is formed on the surface of the medium 12 by ejecting ink onto the medium 12 from each liquid jet head 26 in parallel with the transport of the medium 12 by the transport mechanism 22 and the repetitive reciprocation of the carriage 242 .

1-2. Overall Configuration of Liquid Jet Head FIG. 2 is an exploded perspective view of the liquid jet head 26 according to the first embodiment. FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2, ie, a cross-sectional view parallel to the XZ plane. As illustrated in FIG. 2, the direction perpendicular to the XY plane is hereinafter referred to as the Z direction. The direction in which ink is ejected by each liquid ejecting head 26, typically the vertical direction, corresponds to the Z direction.

As illustrated in FIGS. 2 and 3, the liquid jet head 26 includes a substantially rectangular channel substrate 32 elongated in the Y direction. A pressure chamber substrate 34 , a vibration plate 36 , a plurality of piezoelectric elements 38 , a housing portion 42 , and a sealing body 44 are installed on the negative surface of the flow path substrate 32 in the Z direction. On the other hand, a nozzle plate 46 and a vibration absorber 48 are installed on the positive surface of the flow path substrate 32 in the Z direction. Each element of the liquid jet head 26 is roughly a plate-like member elongated in the Y direction similarly to the channel substrate 32, and is joined to each other using an adhesive, for example.

As illustrated in FIG. 2, the nozzle plate 46 is a plate-like member formed with a plurality of nozzles N arranged in the Y direction. Each nozzle N is a through hole through which ink passes. The channel substrate 32, the pressure chamber substrate 34, and the nozzle plate 46 are formed by processing, for example, a silicon (Si) single crystal substrate by semiconductor manufacturing techniques such as etching. However, the material and manufacturing method of each element of the liquid jet head 26 are arbitrary. The Y direction can also be rephrased as the direction in which the plurality of nozzles N are arranged.

The channel substrate 32 is a plate-like member for forming an ink channel. As illustrated in FIGS. 2 and 3 , the channel substrate 32 is formed with an opening 322 , a supply channel 324 and a communication channel 326 . The opening 322 is a through-hole having a long shape along the Y direction in plan view from the Z direction so as to extend continuously over the plurality of nozzles N. As shown in FIG. On the other hand, the supply channel 324 and the communication channel 326 are through-holes individually formed for each nozzle N. As shown in FIG. Further, as illustrated in FIG. 3 , a relay channel 328 extending over a plurality of supply channels 324 is formed on the surface of the channel substrate 32 on the positive side in the Z direction. The relay channel 328 is a channel that allows the opening 322 and the plurality of supply channels 324 to communicate with each other. In addition, below, the planar view from Z direction is also simply called "planar view."

The housing part 42 is a structure manufactured by, for example, injection molding of a resin material, and is fixed to the surface of the channel substrate 32 on the negative side in the Z direction. As illustrated in FIG. 3 , housing portion 422 and introduction port 424 are formed in housing portion 42 . The accommodating portion 422 is a recess having an outer shape corresponding to the opening 322 of the channel substrate 32 , and the introduction port 424 is a through hole communicating with the accommodating portion 422 . As understood from FIG. 3, the space that allows the opening 322 of the channel substrate 32 and the housing 422 of the housing 42 to communicate with each other functions as a liquid storage chamber R, which is a reservoir. Ink supplied from the liquid container 14 and passing through the inlet 424 is stored in the liquid storage chamber R. As shown in FIG.

The vibration absorber 48 is an element for absorbing pressure fluctuations in the liquid storage chamber R, and includes, for example, a compliance substrate that is a flexible sheet member capable of elastic deformation. Specifically, the flow path substrate 32 is moved in the Z direction so that the opening 322, the relay flow path 328, and the plurality of supply flow paths 324 of the flow path substrate 32 are closed to form the bottom surface of the liquid storage chamber R. A vibration absorber 48 is installed on the positive surface of .

As illustrated in FIGS. 2 and 3, the pressure chamber substrate 34 is a plate-like member in which a plurality of pressure chambers C corresponding to different nozzles N are formed. A plurality of pressure chambers C are arranged along the Y direction. Each pressure chamber C is a cavity formed by using holes 341 that open on both sides of the pressure chamber substrate 34, and has an elongated shape along the X direction in plan view. The end of the pressure chamber C on the positive side in the X direction overlaps one supply channel 324 of the channel substrate 32 in plan view, and the end of the pressure chamber C on the negative side in the X direction overlaps the channel substrate in plan view. It overlaps one communicating channel 326 of 32 .

A vibration plate 36 is installed on the surface of the pressure chamber substrate 34 opposite to the flow path substrate 32 . The diaphragm 36 is an elastically deformable plate-like member. As exemplified in FIG. 3, the diaphragm 36 of the first embodiment is composed of a lamination of a first layer 361 and a second layer 362 . The second layer 362 is located on the side opposite to the pressure chamber substrate 34 when viewed from the first layer 361 . The first layer 361 is an elastic film made of an elastic material such as silicon oxide (SiO ₂ ), and the second layer 362 is an insulating film made of an insulating material such as zirconium oxide (ZrO ₂ ). The first layer 361 and the second layer 362 are each formed by known deposition techniques such as thermal oxidation or sputtering. Part or all of the pressure chamber substrate 34 and the vibration plate 36 can be removed by selectively removing a portion of the region corresponding to the pressure chambers C in the thickness direction of the plate-shaped member having a predetermined thickness. It is also possible to form them integrally.

As can be understood from FIG. 3, the channel substrate 32 and the vibration plate 36 are opposed to each other inside each pressure chamber C with a space therebetween. The pressure chamber C is located between the flow path substrate 32 and the vibration plate 36 and is a space for applying pressure to the ink filled in the pressure chamber C. As shown in FIG. The ink stored in the liquid storage chamber R branches from the relay flow path 328 to each supply flow path 324 and is supplied and filled in the plurality of pressure chambers C in parallel. As can be understood from the above description, the diaphragm 36 constitutes a part of the wall surface of the pressure chamber C, specifically the upper surface which is one surface of the pressure chamber C. As shown in FIG.

As illustrated in FIGS. 2 and 3, a plurality of piezoelectric elements corresponding to different nozzles N or pressure chambers C are formed on the surface of the vibration plate 36 opposite to the pressure chambers C, that is, the surface of the second layer 362 . An element 38 is installed. Each piezoelectric element 38 is an actuator that is deformed by supply of a drive signal, and has an elongated shape along the X direction in a plan view. The plurality of piezoelectric elements 38 are arranged in the Y direction so as to correspond to the plurality of pressure chambers C. As shown in FIG. When the vibration plate 36 vibrates in conjunction with the deformation of the piezoelectric element 38, the pressure in the pressure chamber C fluctuates, and ink is ejected from the nozzle N.

The sealing body 44 in FIGS. 2 and 3 is a structure that protects the plurality of piezoelectric elements 38 and reinforces the mechanical strength of the pressure chamber substrate 34 and the diaphragm 36, and is adhered to the surface of the diaphragm 36, for example. fixed with an agent. A plurality of piezoelectric elements 38 are accommodated inside recesses formed in the surface of the sealing body 44 facing the diaphragm 36 .

As illustrated in FIG. 3, a wiring substrate 50, for example, is bonded to the surface of the diaphragm 36 or the surface of the pressure chamber substrate 34. As shown in FIG. The wiring board 50 is a mounting component formed with a plurality of wirings for electrically connecting the control unit 20 and the liquid jet head 26 . For example, a flexible wiring board such as FPC (Flexible Printed Circuit) or FFC (Flexible Flat Cable) is preferably employed as the wiring board 50 . A drive signal for driving the piezoelectric elements 38 is supplied from the wiring board 50 to each piezoelectric element 38 .

1-3. Details of Pressure Chamber and Diaphragm FIG. 4 is a plan view showing the diaphragm 36 of the liquid jet head 26 according to the first embodiment. FIG. 5 is a cross-sectional view taken along line VV of FIG. 6 is a cross-sectional view taken along line VI-VI of FIG. 4. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 4. FIG. As shown in FIG. 4, the diaphragm 36 has a plurality of vibration regions V having shapes corresponding to the plurality of pressure chambers C in plan view. A vibration region V is a region of the vibration plate 36 that is vibrated by the piezoelectric element 38 . In other words, the vibration region V is a region of the vibration plate 36 that can vibrate without coming into contact with the pressure chamber substrate 34 .

Here, as described above, each pressure chamber C has an elongated shape along the X direction, which is the first direction, in plan view. Therefore, each vibration region V has a longitudinal shape extending along the X direction in plan view. Each pressure chamber C is formed, for example, by anisotropically etching a silicon single crystal substrate having a (110) surface. Therefore, the planar shape of each pressure chamber C or each vibration region V is a shape along the (111) plane of the single crystal substrate. The planar shape of each pressure chamber C or each vibration region V is not limited to the illustrated shape.

A corrosion resistant film 35 is arranged on the wall surface of the pressure chamber C to protect the wall surface from ink. The corrosion-resistant film 35 has higher resistance to the ink inside the pressure chamber C than the vibration plate 36 . The material constituting the corrosion-resistant film 35 is not particularly limited as long as it is resistant to the ink in the pressure chamber C. Examples include silicon oxides such as silicon oxide (SiO ₂ ) and tantalum oxide (TaO _x ). and metal oxides such as zirconium oxide (ZrO ₂ ), and metals such as nickel (Ni) and chromium (Cr). The corrosion-resistant film 35 may be composed of a single layer of a single material, or may be composed of a laminate of multiple layers of different materials. Although the thickness of the corrosion-resistant film 35 is not particularly limited, it is preferably in the range of 0.1 μm or more and 1000 μm or less. The corrosion-resistant film 35 may be provided as required, and may be omitted. Further, it can be said that a part of the corrosion-resistant film 35 has a function of reinforcing the vibration region V together with the reinforcing film 37 described later.

As shown in FIG. 5, a reinforcement film 37 for reinforcing the vibration region V is arranged on the surface of the vibration region V of the diaphragm 36 on the pressure chamber C side. In this embodiment, a reinforcement film 37 is arranged on the corrosion-resistant film 35 described above. Further, the reinforcing film 37 is unevenly distributed near the center of the vibration region V in the longitudinal direction. That is, the vibration region V consists of a first region V1 in which the reinforcing film 37 is not arranged and a second region in which the reinforcing film 37 is arranged, which is closer to the center of the vibration region V in the longitudinal direction than the first region V1. V2 and A vibration region V shown in FIG. 5 includes two first regions V1 and a second region V2 positioned between the two first regions V1.

Here, as described above, the liquid jet head 26 has the pressure chamber substrate 34, which is the substrate on which the vibration plate 36 is arranged. As shown in FIGS. 5, 6 and 7, the pressure chamber substrate 34 is provided with holes 341 forming the pressure chambers C. As shown in FIGS. As shown in FIGS. 6 and 7, a wall-shaped partition 342 extending along the X direction is provided between two adjacent pressure chambers C of the pressure chamber substrate 34 . As shown in FIG. 7, the reinforcing film 37 is arranged on the corner where the pressure chamber C side surface of the diaphragm 36 and the wall surface of the hole 341 are connected. At this corner, the diaphragm 36 is most likely to experience stress. Therefore, by arranging the reinforcement film 37 on the corner, the diaphragm 36 can be effectively reinforced. Further, the reinforcing film 37 is preferably arranged in a region between the piezoelectric element 38 and the outer edge of the pressure chamber C in plan view. Since the diaphragm 36 is not reinforced by the piezoelectric element 38 in this area, it can be said that the diaphragm 36 is easily damaged. Therefore, reinforcing the region with the reinforcing film 37 is effective in preventing damage to the diaphragm 36 .

Note that the reinforcing film 37 may be arranged on a surface of the wall surface of the pressure chamber C other than the area described above. For example, in FIG. 7, the reinforcement films 37 are unevenly arranged on both ends of the vibration region V in the Y direction, but the reinforcement film 37 may be arranged in the center of the vibration region V in the Y direction. However, if the reinforcement film 37 is unevenly distributed on both ends of the vibration region V in the Y direction and thus the reinforcement film 37 is not formed in the center in the Y direction, the reinforcement film 37 is not formed in the center of the vibration region V in the Y direction. Compared to the case where it is arranged in the center of the , the effect of reducing damage to the vibration region V is high, and the necessary deformation of the vibration region V can be easily obtained, which is preferable.

The constituent material of the reinforcing film 37 is not particularly limited, and various organic materials and various inorganic materials can be used. Examples of the organic material include resin materials such as resist materials. Examples of the inorganic material include metals and metal oxides. The reinforcing film 37 may be composed of a single layer of a single material, or may be composed of a laminate of multiple layers of different materials. The constituent material of the reinforcing film 37 may be the same as or different from the constituent material of the corrosion-resistant film 35 described above, but from the viewpoint of enhancing the reinforcing effect of the reinforcing film 37, the material has a Young's modulus higher than that of the corrosion-resistant film 35 described above. is preferred. Further, in the case of the present embodiment, the reinforcing film 37 is exposed to the ink, so the constituent material of the reinforcing film 37 preferably has ink resistance.

Here, from the viewpoint that the rigidity of the reinforcement film 37 can be easily increased, the Young's modulus of the constituent material of the reinforcement film 37 is preferably 10 GPa or more, more preferably 50 GPa or more. From this point of view, the constituent material of the reinforcing film 37 is preferably metal or metal oxide.

Metals generally have a higher Young's modulus than organic materials, and are superior in toughness to silicon, metal oxides, and the like. Therefore, by forming the reinforcement film 37 from metal, the reinforcement film 37 is less likely to be damaged, and as a result, damage such as cracks in the vibration region V can be effectively prevented. In particular, in this embodiment, since the reinforcing film 37 is exposed to ink, the metal forming the reinforcing film 37 is preferably a chemically stable metal. (Pt), nickel (Ni), or the like is preferably used. Here, nickel has a higher Young's modulus than gold and platinum, and is therefore preferable in terms of easily increasing the rigidity of the reinforcing film 37 . Gold and platinum are preferred because they are chemically more stable than nickel.

Metal oxides generally have a higher Young's modulus than metals. Therefore, by forming the reinforcement film 37 with a metal oxide, the rigidity of the reinforcement film 37 can be easily increased, and as a result, damage such as cracks in the vibration region V can be effectively prevented. In particular, in the present embodiment, since the reinforcing film 37 is exposed to ink, the metal oxide constituting the reinforcing film 37 is preferably a chemically stable metal oxide. Al ₂ O ₃ ), silicon oxide (SiO _x ), silicon nitride (SiN _x ), tantalum oxide (TaO _x ), yttria-stabilized zirconia (YSZ), zirconia (ZrO ₂ ), and the like.

A piezoelectric element 38 is arranged on the surface of the vibration plate 36 opposite to the pressure chambers C. As shown in FIG. As exemplified in FIGS. 5, 6 and 7, the piezoelectric element 38 is schematically configured by stacking a first electrode 381, a piezoelectric layer 383 and a second electrode 382. As shown in FIGS. The first electrode 381, the piezoelectric layer 383, and the second electrode 382 are each formed by a known film forming technique such as sputtering, and a known processing technique using photolithography, etching, and the like. It should be noted that another layer such as a layer that enhances adhesion may be appropriately interposed between the laminated layers and between the piezoelectric element 38 and the vibration plate 36 .

The first electrode 381 is arranged on the surface of the diaphragm 36 , specifically on the surface of the second layer 362 opposite to the first layer 361 . The first electrodes 381 are individual electrodes that are spaced apart from each other for each piezoelectric element 38 . Specifically, a plurality of first electrodes 381 extending in the X direction are arranged in the Y direction at intervals. A drive signal for ejecting ink from the nozzle N corresponding to the piezoelectric element 38 is applied to the first electrode 381 of each piezoelectric element 38 via the wiring board 50 .

The piezoelectric layer 383 is arranged on the surface of the first electrode 381 . The piezoelectric layer 383 has a strip shape extending in the Y direction so as to be continuous across the plurality of piezoelectric elements 38 . Although not shown, through-holes extending in the X direction are provided through the piezoelectric layer 383 in regions of the piezoelectric layer 383 corresponding to the gaps between the pressure chambers C adjacent to each other in plan view. The constituent material of the piezoelectric layer 383 is, for example, a piezoelectric material such as lead zirconate titanate.

The second electrode 382 is arranged on the surface of the piezoelectric layer 383 . Specifically, the second electrode 382 is a strip-shaped common electrode that extends in the Y direction so as to be continuous across the plurality of piezoelectric elements 38 . A predetermined reference voltage is applied to the second electrode 382 .

As described above, the piezoelectric element 38 includes the first electrode 381 arranged on the surface of the diaphragm 36, the second electrode 382 arranged with the first electrode 381 sandwiched between the diaphragm 36, the second and a piezoelectric layer 383 disposed between the first electrode 381 and the second electrode 382 . In this way, piezoelectric element 38 is placed directly on diaphragm 36 . Therefore, the driving force from the piezoelectric element 38 can be efficiently transmitted to the diaphragm 36 as compared with the case where the piezoelectric element 38 is arranged on the diaphragm 36 via another member.

The liquid jet head 26 described above includes a vibration plate 36 forming a part of the wall surface of the pressure chamber C containing ink, which is an example of a liquid, a piezoelectric element 38 for vibrating the vibration plate 36 , and a pressure chamber of the vibration plate 36 . and a reinforcing film 37 disposed on the C-side surface. Here, the vibration region V, which is the region of the vibration plate 36 and is vibrated by the piezoelectric element 38, has a longitudinal shape in a plan view seen from the thickness direction of the vibration plate 36. As shown in FIG. The vibration region V consists of a first region V1 in which the reinforcement film 37 is not arranged, and a second region V2 which is located closer to the center of the vibration region V in the longitudinal direction than the first region V1 and in which the reinforcement film 37 is arranged. ,including.

Thus, the reinforcement film 37 is arranged in the second region V2 of the vibration region V, but is not arranged in the first region V1. Therefore, it is possible to reduce the damage to the center of the vibration region V in the X direction due to the reaction force from the ink in the pressure chamber C while ensuring the deformation amount necessary for the entire vibration region V. FIG.

More specifically, since the reinforcing film 37 is arranged in the second region V2, the deformation of the second region V2 becomes difficult. Therefore, compared with the case where the reinforcing film 37 is not arranged in the vibration region V, deformation of the center of the vibration region V in the X direction due to the reaction force from the ink in the pressure chamber C can be reduced. On the other hand, since the reinforcing film 37 is not arranged in the first region V1 of the vibration region V, the first region V1 deforms more easily than the second region V2. Therefore, the amount of deformation necessary for vibrating the entire vibrating region V can be ensured.

Moreover, the second region V2 is positioned closer to the center of the vibration region V in the longitudinal direction than the first region V1. That is, the reinforcement film 37 is unevenly distributed near the center of the vibration region V in the longitudinal direction. Therefore, compared to the case where the reinforcement film 37 is unevenly distributed near the ends in the longitudinal direction of the vibration region V, the center of the vibration region V in the X direction can be located while securing the deformation amount necessary for the entire vibration region V. Deformation due to the reaction force from the ink in the pressure chamber C can be easily reduced.

When the aforementioned multiple nozzles N are arranged at a high density of 300 dpi or more, the width W of the vibration region V becomes extremely small. In this case, in order to secure the necessary amount of deformation of the vibration region V, it is necessary to reduce the thickness of the vibration region V, and damage such as cracks in the vibration region V tends to occur. In this embodiment, even in this case, it is possible to prevent the center of the vibration region V in the X direction from being damaged by the reaction force from the ink in the pressure chamber C while ensuring the deformation amount necessary for the entire vibration region V. can be reduced.

Further, the liquid ejecting apparatus 100 having the liquid ejecting head 26 that produces such effects can stably achieve high-definition liquid ejection over a long period of time. Also, by arranging the plurality of nozzles N at a high density, the size of the liquid ejecting head 26 can be reduced, and accordingly the size of the liquid ejecting apparatus 100 having the liquid ejecting head 26 can be reduced.

From the viewpoint of easily obtaining the aforementioned effects of the liquid jet head 26, when the length of the vibration region V along the X direction is L, and the length of the second region V2 or the reinforcing film 37 along the X direction is L2, L2/L is preferably in the range of 0.1 or more and 0.5 or less, and more preferably in the range of 0.1 or more and 0.3 or less.

FIG. 8 is a diagram showing the relationship between the thickness T of the reinforcing film 37 and the primary natural vibration mode of the vibration region V in the first embodiment. The vibration region V has multiple natural vibration modes. Among the plurality of natural vibration modes, the first to third natural vibration modes having both ends VR and VL in the longitudinal direction of the vibration region V as fixed ends have larger amplitudes than the other natural vibration modes. Area V is likely to cause damage. In particular, the primary natural vibration mode has a larger amplitude than other natural vibration modes. Therefore, as shown in FIG. 8, the reinforcing film 37 includes the position of the antinode of the first-order natural vibration mode, that is, the center VC of the vibration region V in the longitudinal direction. Therefore, compared with the case where the reinforcement film 37 does not include the center VC of the vibration region V, damage to the vibration region V can be effectively reduced.

In this embodiment, as shown in FIG. 8, the thickness T of the reinforcing film 37 is constant at the thickness T2 in the second region V2. Although the thickness T of the reinforcing film 37 is not particularly limited, it is preferably in the range of 0.1 μm or more and 1000 μm or less. When the thickness T is within this range, it is possible to obtain the required rigidity of the aforementioned reinforcing film 37 while facilitating the formation of the reinforcing film 37 . Note that the thickness T of the reinforcement film 37 along the Y direction may decrease continuously from the second region V2 side toward the first region V1 side. In this case, stress concentration occurring between the first region V1 and the second region V2 can be reduced.

1-4. Manufacturing Method of Pressure Chamber FIG. As shown in FIG. 9, the manufacturing process of the pressure chamber C includes a mask forming process S1, an etching process S2, a mask removing process S3, a corrosion resistant film forming process S4, and a reinforcement film forming process S5. An outline of each step will be described below.

FIG. 10 is a cross-sectional view showing the mask forming step S1. As shown in FIG. 10, in the mask forming step S1, first, a substrate 340, which is a silicon single crystal substrate having a (110) plane, is prepared. The substrate 340 is a substrate that becomes the pressure chamber substrate 34 described above. A mask M1 having an opening M11 is formed on the upper surface of the substrate 340 in FIG. Here, the vibration plate 36 is formed on the lower surface of the substrate 340 in FIG. In the example shown in FIG. 10, a piezoelectric element 38 is formed on the diaphragm 36 .

More specifically, first, a first layer 361 and a second layer 362 are sequentially formed in this order on the lower surface of the substrate 340 in FIG. Thereby, the diaphragm 36 is formed. The first layer 361 is formed, for example, by thermal oxidation of the lower surface in FIG. 10 of the substrate 340 if it is composed of silicon oxide. For example, when the second layer 362 is made of zirconium oxide, it is formed by forming a zirconium layer on the first layer 361 by a known film forming technique such as sputtering and thermally oxidizing the layer.

After forming the diaphragm 36, a first electrode 381, a piezoelectric layer 383, and a second electrode 382 are formed on the diaphragm 36 in this order. Thereby, the piezoelectric element 38 is formed. The first electrode 381, the piezoelectric layer 383, and the second electrode 382 are each formed by a known film forming technique such as sputtering, and a known processing technique using photolithography, etching, and the like. After the piezoelectric element 38 is formed, the upper surface of the substrate 340 in FIG. 10 is ground by CMP (chemical mechanical polishing) or the like to planarize the surface or adjust the thickness of the substrate 340, if necessary.

After forming the piezoelectric element 38, a mask M1 having an opening M11 is formed on the upper surface of the substrate 340 in FIG. The mask M1 is formed by, for example, a known film formation technique such as sputtering, and a known processing technique using photolithography, etching, and the like. Here, the mask M1 is made of a material, such as silicon nitride (SiN), which is resistant to an etchant used in the etching step S2, which will be described later.

FIG. 11 is a cross-sectional view showing the etching step S2. As shown in FIG. 11, in the etching step S2, the substrate 340 is anisotropically etched through the openings M11 of the mask M1. A hole 341 is formed by the anisotropic etching. For example, an aqueous potassium hydroxide solution (KOH) or the like is used as an etchant for the anisotropic etching.

In the anisotropic etching, the etching rate for the (111) plane of the substrate 340 is much lower than the etching rate for the (110) plane of the substrate 340 . Therefore, etching progresses in the thickness direction of the substrate 340, and a hole 341 having a (111) plane as a wall surface is formed. Here, the vibration plate 36 functions as a stop layer that stops the anisotropic etching. However, after stopping the anisotropic etching, the vibration plate 36 is exposed to the etchant and is isotropically etched by the etchant in a small amount.

FIG. 12 is a cross-sectional view showing the mask removing step S3. As shown in FIG. 12, the mask M1 is removed in the mask removing step S3. For removing the mask M1, a liquid capable of dissolving the mask M1, for example, hydrofluoric acid (HF) when the mask M1 is made of silicon nitride, is used as a removing liquid.

FIG. 13 is a cross-sectional view showing the corrosion-resistant film forming step S4. As shown in FIG. 13, a corrosion-resistant film 35 is formed in the corrosion-resistant film forming step S4. For example, the corrosion-resistant film 35 is formed by a known film forming technique such as sputtering, and a known processing technique using photolithography, etching, and the like. In FIG. 13, the corrosion-resistant film 35 is not formed on the end surface of the partition 342 of the substrate 340 opposite to the diaphragm 36, but the corrosion-resistant film 35 may be formed on the end surface. In this case, the anti-corrosion film 35 can be formed simply by forming a film by sputtering or the like.

FIG. 14 is a cross-sectional view showing the reinforcing film forming step S5. As shown in FIG. 14, a reinforcing film 37 is formed in the reinforcing film forming step S5. For example, the reinforcement film 37 is formed by a known film formation technique such as sputtering, and a known processing technique using photolithography, etching, and the like. The reinforcing film 37 can also be formed by film formation by physical vapor deposition or chemical vapor deposition using a mask, as described below.

FIG. 15 is a cross-sectional view showing the first step of the reinforcing film forming step S5. FIG. 16 is a cross-sectional view showing the second step of the reinforcing film forming step S5. In the first step shown in FIG. 15, a part of the reinforcing film 37 is formed by forming a film using the mask M2, and then in the second step shown in FIG. to form

Specifically, as shown in FIG. 15, in the first step, first, a mask M2 having an opening M21 is arranged on the upper side of the substrate 340 in FIG. Mask M2 is a substrate having an opening M21. The opening M21 is arranged corresponding to the region where the reinforcing film 37 is to be formed. In the first step, the vapor deposition material is vapor-deposited from a direction α1 that is inclined with respect to the normal direction of the substrate 340 . Therefore, the arrangement of the opening M21 is determined according to the direction α1. Examples of the constituent material of the mask M2 include metal, glass, silicon, and the like. Among others, it is preferable that the material of the mask M2 has a linear expansion coefficient difference as small as possible from that of the material of the substrate 340. Specifically, silicon is preferable. By reducing the difference in coefficient of linear expansion between the mask M2 and the substrate 340, the positional deviation of the opening M21 with respect to the substrate 340 can be reduced. After the above-described first step, as shown in FIG. 16, in the second step, the mask M2 is rearranged as necessary so that it is inclined in the direction opposite to the direction α1 with respect to the normal direction of the substrate 340. A vapor deposition material is vapor-deposited from direction α2.

The vapor deposition used in the first step and the second step may be either physical vapor deposition or chemical vapor deposition, but from the viewpoint of simplicity, physical vapor deposition is preferred, and more specifically, a denser film can be obtained than vacuum vapor deposition. Ion beam assisted vapor deposition, ion plating, or the like is preferable from the viewpoint of being able to

2. Second Embodiment A second embodiment of the present invention will be described. Note that, in each of the following illustrations, the reference numerals of the first embodiment are used for the elements whose functions are the same as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

FIG. 17 is a cross-sectional view showing the pressure chamber C in the second embodiment. In this embodiment shown in FIG. 17 as well, the corrosion resistant film 35 is arranged on the wall surface of the pressure chamber C. As shown in FIG. However, in this embodiment, the reinforcement film 37 is arranged between the wall surface of the pressure chamber C and the corrosion-resistant film 35 . Here, the corrosion resistant film 35 has higher resistance to the ink inside the pressure chamber C than the vibration plate 36 . For this reason, the constituent material of the reinforcing film 37 does not matter whether it has resistance to the ink inside the pressure chamber C or not. As a result, the choice of materials for the reinforcement film 37 can be expanded, the degree of freedom in designing the reinforcement film 37 can be increased, and the formation of the reinforcement film 37 can be simplified. Also in this embodiment, the same effects as those of the above-described first embodiment can be obtained.

3. Third Embodiment A third embodiment of the present invention will be described. Note that, in each of the following illustrations, the reference numerals of the first embodiment are used for the elements whose functions are the same as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

FIG. 18 is a cross-sectional view showing the pressure chamber C in the third embodiment. In this embodiment shown in FIG. 18, on the wall surface of the pressure chamber C, a corrosion-resistant film 35 and a reinforcing film 37 are arranged. The reinforcement film 37 is arranged on the corner where the pressure chamber C side surface of the diaphragm 36 and the wall surface of the hole 341 are connected. The corrosion-resistant film 35 is arranged over the entire wall surface of the pressure chamber C except for the region where the reinforcing film 37 is arranged.

The constituent material of the reinforcing film 37 may be the same as or different from the constituent material of the corrosion-resistant film 35 . However, as in the first embodiment, the reinforcing film 37 of the present embodiment is exposed to the ink in the pressure chamber C, so it is preferable that it has a resistance to the ink. Further, when the material of the reinforcement film 37 is different from the material of the corrosion-resistant film 35 , it is preferable that the material has a Young's modulus higher than that of the material of the corrosion-resistant film 35 . In this case, the reinforcement film 37 is formed, for example, by modifying a part of the corrosion-resistant film 35 with an ion beam or the like. Note that the reinforcement film 37 may be formed by film formation separately from the corrosion-resistant film 35 .

In this embodiment using the reinforcing film 37 as described above, the same effects as those of the above-described first embodiment can be obtained.

4. Fourth Embodiment A fourth embodiment of the present invention will be described. Note that, in each of the following illustrations, the reference numerals of the first embodiment are used for the elements whose functions are the same as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

FIG. 19 is a longitudinal sectional view showing the pressure chamber C in the fourth embodiment. The liquid jet head 26 shown in FIG. 19 includes a vibration plate 36 forming part of a wall surface of a pressure chamber C containing ink, which is an example of a liquid, a piezoelectric element 38 for vibrating the vibration plate 36, and a vibration plate 36. and a reinforcing film 37 arranged on the surface on the pressure chamber C side. Here, the vibration region V, which is the region of the vibration plate 36 and is vibrated by the piezoelectric element 38, has a longitudinal shape in a plan view seen from the thickness direction of the vibration plate 36. As shown in FIG. The reinforcing film 37 is arranged at a position closer to the center of the vibration region V in the longitudinal direction than the first portion 371 having the first film thickness T1 and the second film having a thickness greater than the first film thickness T1. and a second portion 372 of thickness T2.

Since the reinforcing film 37 has the first portion 371 and the second portion 372, which have two different film thicknesses, the amount of deformation necessary for the entire vibration region V can be obtained as in the first embodiment. It is possible to reduce the damage to the center of the vibration region V in the X direction due to the reaction force from the ink in the pressure chamber C while ensuring this.

Although the ratio T1/T2 of the first film thickness T1 and the second film thickness T2 is not particularly limited, it is preferably within the range of 0.1 or more and 0.5 or less. When the ratio T1/T2 is within this range, it is possible to obtain the required rigidity of the aforementioned reinforcing film 37 while facilitating the formation of the reinforcing film 37 .

FIG. 20 is a diagram showing the relationship between the thickness T of the reinforcement film 37 and the primary natural vibration mode of the diaphragm 36 in the fourth embodiment. In this embodiment, the second portion 372 is arranged at the center VC of the vibration region V in the longitudinal direction. The center VC in the longitudinal direction of the vibration region V is the position of the antinode of the primary natural vibration mode of the vibration region V as described above. Therefore, compared with the case where the second portion 372 is not arranged at the center VC of the vibration region V, damage to the vibration region V can be effectively reduced.

In this embodiment, as shown in FIG. 20, the thickness T of the reinforcing film 37 is continuously reduced from the second region V2 side toward the first region V1 side. Therefore, the stress concentration occurring between the first region V1 and the second region V2 can be reduced as compared with the case where the thickness T of the reinforcing film 37 changes rapidly between the first region V1 and the second region V2. can be reduced. Note that the change in the thickness T of the reinforcing film 37 along the Y direction is not limited to the change shown in FIG. good too.

5. Fifth Embodiment A fifth embodiment of the present invention will be described. Note that, in each of the following illustrations, the reference numerals of the first embodiment are used for the elements whose functions are the same as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

FIG. 21 is a diagram showing the relationship between the thickness T of the reinforcing film 37 and the secondary natural vibration mode of the vibration region V in the fifth embodiment. The reinforcing membrane 37 has three first portions 371 and two second portions 372 . The two second portions 372 are the antinode positions of the second-order natural vibration mode of the vibration region V. FIG. Therefore, damage caused by the secondary natural vibration mode of the vibration region V can be effectively reduced. In this embodiment using the reinforcing film 37 as described above, the same effects as those of the above-described first embodiment can be obtained. Note that the first portion 371 may be omitted.

6. Sixth Embodiment A sixth embodiment of the present invention will be described. Note that, in each of the following illustrations, the reference numerals of the first embodiment are used for the elements whose functions are the same as those of the first embodiment, and detailed descriptions thereof are appropriately omitted.

FIG. 22 is a diagram showing the relationship between the thickness T of the reinforcing film 37 and the third-order natural vibration mode of the vibration region V in the sixth embodiment. The reinforcement film 37 has four first portions 371 and three second portions 372 . The three second portions 372 are the antinode positions of the third-order natural vibration mode of the vibration region V. FIG. Therefore, damage caused by the third-order natural vibration mode of the vibration region V can be effectively reduced. In this embodiment using the reinforcing film 37 as described above, the same effects as those of the above-described first embodiment can be obtained. Note that the first portion 371 may be omitted.

<Modification>
Each form in the above illustration can be variously modified. Specific modifications that can be applied to each of the above-described modes are exemplified below. In addition, two or more aspects arbitrarily selected from the following examples can be appropriately combined within a mutually consistent range.

(1) In each of the above embodiments, the first electrode 381 is an individual electrode and the second electrode 382 is a common electrode. , the second electrode 382 may be an individual electrode for each piezoelectric element 38 . Also, both the first electrode 381 and the second electrode 382 may be individual electrodes.

(2) In each of the above-described embodiments, the serial type liquid ejecting apparatus 100 in which the carriage 242 on which the liquid ejecting head 26 is mounted is reciprocated is exemplified. The present invention can also be applied to devices.

(3) The liquid ejecting apparatus 100 exemplified in each of the above embodiments can be employed in various types of equipment such as facsimile machines and copiers, in addition to equipment dedicated to printing. However, the application of the liquid ejecting apparatus of the present invention is not limited to printing. For example, a liquid ejecting apparatus that ejects a colorant solution is used as a manufacturing apparatus for forming a color filter of a liquid crystal display device. Also, a liquid ejecting apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus for forming wiring and electrodes of a wiring board.

26 Liquid jet head 34 Pressure chamber substrate 35 Corrosion resistant film 36 Diaphragm 37 Reinforcement film 38 Piezoelectric element 100 Liquid jet device 341 Hole 371 First portion 372 Second portion 381 First electrode 382 Second electrode 383 Piezoelectric layer C Pressure chamber T1 First thickness T2 Second thickness V Vibration region V1 First Regions, V2 . . . second region.

Claims (11)

a diaphragm forming part of the wall surface of the pressure chamber containing the liquid;
a piezoelectric element that vibrates the diaphragm;
a reinforcing film disposed on the surface of the diaphragm on the pressure chamber side;
The vibrating region, which is the region of the diaphragm and is vibrated by the piezoelectric element, has a longitudinal shape in a plan view viewed from the thickness direction of the diaphragm,
The vibration region includes a first region where the reinforcing film is not arranged, and a second region which is located closer to the center of the vibration region in the longitudinal direction than the first region and where the reinforcing film is arranged. Includes
,
The second region has one of the first, second, and third natural vibration modes of the vibration region.
A liquid jet head placed at the belly position . a diaphragm forming part of the wall surface of the pressure chamber containing the liquid;
a piezoelectric element that vibrates the diaphragm;
a reinforcing film disposed on the surface of the diaphragm on the pressure chamber side;
The vibrating region, which is the region of the diaphragm and is vibrated by the piezoelectric element, has a longitudinal shape in a plan view viewed from the thickness direction of the diaphragm,
The reinforcing film is arranged at a first portion having a first film thickness and a position closer to the center in the longitudinal direction of the vibration region than the first portion, and having a second film thickness thicker than the first film thickness. a second portion ;
The second portion is of any one of the first, second, and third natural vibration modes of the vibration region.
A liquid jet head placed at the belly position . 3. The liquid jet head according to claim 2, wherein the second portion is arranged in the center of the vibration area in the longitudinal direction. The piezoelectric element is
a first electrode;
a second electrode arranged with the first electrode interposed between itself and the diaphragm;
and a piezoelectric layer disposed between the first electrode and the second electrode.
3
The liquid jet head according to any one of . a substrate on which the diaphragm is arranged and a hole forming the pressure chamber is provided;
5. The liquid jet head according to claim 1 , wherein the reinforcing film is arranged on a corner where a surface of the diaphragm on the side of the pressure chamber and a wall surface of the hole are connected. a corrosion-resistant film disposed on the wall surface of the pressure chamber and having a higher resistance to the liquid than the vibration plate;
6. The reinforcing film is arranged between the wall surface of the pressure chamber and the corrosion resistant film.
The liquid jet head according to any one of . 7. The liquid jet head according to claim 1 , wherein the reinforcing film is made of metal. 7. The liquid jet head according to claim 1 , wherein the reinforcing film is made of metal oxide. a diaphragm forming part of the wall surface of the pressure chamber containing the liquid;
a piezoelectric element that vibrates the diaphragm;
a reinforcing film disposed on the surface of the diaphragm on the pressure chamber side;
The vibrating region, which is the region of the diaphragm and is vibrated by the piezoelectric element, is the thickness of the diaphragm.
In a plan view from the direction, it has a longitudinal shape,
The vibration region includes a first region in which the reinforcing film is not arranged and
a second region located near the center in the longitudinal direction of the region and in which the reinforcing film is arranged;
,
A corrosion-resistant film disposed on a wall surface of the pressure chamber and having higher resistance to the liquid than the diaphragm
has
The liquid jet head, wherein the reinforcement film is arranged between the wall surface of the pressure chamber and the corrosion-resistant film. a diaphragm forming part of the wall surface of the pressure chamber containing the liquid;
a piezoelectric element that vibrates the diaphragm;
a reinforcing film disposed on the surface of the diaphragm on the pressure chamber side;
The vibrating region, which is the region of the diaphragm and is vibrated by the piezoelectric element, is the thickness of the diaphragm.
In a plan view from the direction, it has a longitudinal shape,
The reinforcement film has a first portion having a first film thickness and a longitudinal direction of the vibration region that is longer than the first portion.
a second portion having a second film thickness that is located near the center of the and is thicker than the first film thickness;
A corrosion-resistant film disposed on a wall surface of the pressure chamber and having higher resistance to the liquid than the diaphragm
has
The liquid jet head, wherein the reinforcement film is arranged between the wall surface of the pressure chamber and the corrosion-resistant film. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1 .

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