JP2008037004A - Inkjet head and manufacturing method for inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head good in operating characteristics such as striking characteristic and flying characteristic, and also excellent in productivity, and to provide a manufacturing method for the inkjet head. <P>SOLUTION: The inkjet head is equipped with both a nozzle body which has pressure chambers that pressurize a liquid, and a nozzle plate 11 which has nozzle holes 12 for ejecting the pressurized liquid. A pyramidal inflow port 12a is formed between the pressure chamber and the nozzle hole 12 in a direction to make a cross sectional area smaller towards the nozzle hole 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inkjet head and a method for manufacturing the inkjet head.

  In film-forming devices used for manufacturing recording devices such as consumer printers, liquid crystal display devices, and semiconductor devices, ink and film materials are ejected and ejected toward the target by the ink jet method, and coloring and film formation are performed. Technology is known.

  The discharge head used in this ink jet method is generally called an “ink jet head” and is a precision component manufactured by making use of elaborate techniques. In particular, nozzle holes from which ink and film materials are ejected are required to have extremely high processing accuracy because they greatly affect basic operation characteristics such as landing characteristics and flight characteristics.

However, it is extremely difficult to process such a nozzle hole that requires high precision and high processing accuracy. For this reason, a technique is disclosed in which a nozzle hole is processed into a thin plate so that processing is easy, and the nozzle hole is fixed to and integrated with the nozzle body of the inkjet head with an adhesive or the like (Patent Documents 1 and 2). reference).
However, even if such a technique is used, there is a limit to increasing the processing accuracy of the nozzle holes, and it has also been difficult to stably produce nozzle holes with high processing accuracy.

  Also disclosed is a technique in which a pressure chamber for pressurizing liquid ejected from a nozzle hole is formed into a quadrangular pyramid shape, and the nozzle hole is provided at the bottom of the quadrangular pyramid pressure chamber. (See Patent Document 3).

However, in this technique, the pressure chamber having a quadrangular pyramid shape is processed into the nozzle body. Therefore, the quadrangular pyramid shape of the pressure chamber does not contribute to the processing accuracy of the thin plate nozzle hole processed separately from the nozzle body.
Japanese Patent Laid-Open No. 04-358841 Japanese Patent Laid-Open No. 03-274160 Japanese Patent Laid-Open No. 11-6075

  An object of the present invention is to provide an ink jet head having excellent operational characteristics such as landing characteristics and flight characteristics, and excellent productivity, and an ink jet head manufacturing method.

  According to one aspect of the present invention, a nozzle body having a pressure chamber for pressurizing a liquid and a nozzle plate having a nozzle hole for discharging the pressurized liquid are provided, and the pressure chamber and the nozzle hole There is provided an ink jet head characterized in that a pyramid-shaped inlet is provided in a direction in which the cross-sectional area decreases toward the nozzle hole.

  According to another aspect of the present invention, the step of forming the pyramid-shaped inlet so that the cross-sectional area decreases from the pressure chamber toward the nozzle hole, and the pyramid-shaped inlet is the center hole. There is provided a method for manufacturing an ink jet head, comprising a step of processing a nozzle hole.

  According to the present invention, it is possible to provide an ink jet head having excellent operational characteristics such as landing characteristics and flight characteristics and excellent productivity, and an ink jet head manufacturing method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, an ink jet head according to a first embodiment of the present invention will be described.
FIG. 1 is a schematic diagram for explaining the appearance of an inkjet head.
FIG. 2 is a schematic enlarged view of a cross section in the AA direction of FIG.

  An inkjet head 1 illustrated in FIG. 1 is a so-called multi-nozzle inkjet head having a plurality of nozzle holes 12. There are two types of inkjet head drive methods: thermal type, which generates bubbles by heating and ejects liquid using the film boiling phenomenon, and piezoelectric type, which ejects liquid using bending displacement of piezoelectric elements. However, for convenience of explanation, a piezoelectric type will be described here as an example.

  As shown in FIG. 2, the inkjet head 1 has a structure in which a flexible film 3 is installed on a nozzle body 2 and a piezoelectric element 4 is installed on the flexible film 3. The piezoelectric element 4 is obtained by stacking the lower member 6, the drive electrode 7, the upper member 5, and the drive electrode 8 in this order and then firing them integrally. If the piezoelectric element 4 is integrally fired in this way, the strength is high and handling is easy. A pressure chamber 9 is provided below the nozzle body 2, the upper end of the pressure chamber 9 communicates with the flow path 10, and the lower end opens at one end surface of the nozzle body 2. A plurality of pressure chambers 9 are provided, and a flow path 10 communicating with each pressure chamber 9 exists. Below the nozzle body 2, a nozzle plate 11 is installed, and a nozzle hole 12 is provided so as to communicate with the pressure chamber 9. An inlet 12 a is provided between the pressure chamber 9 and the nozzle hole 12. However, these arrangements and shapes are not limited to those illustrated in FIG. 1, and various modifications can be made. For example, each pressure chamber 9 may not communicate with each flow path 10, and the flow path 10 may communicate with a plurality of pressure chambers 9. Also for the piezoelectric element 4, the lower member 6 is structurally a diaphragm and the upper member 5 is a piezoelectric body. However, the present invention is not limited to this, and various drive types that cause displacement can also be adopted. .

  The material of the nozzle body 2 can be stainless steel or nickel alloy, and the material of the flexible film 3 can be polyethylene terephthalate. The material of the lower member 6 and the upper member 5 of the piezoelectric element 4 can be piezoelectric ceramics (for example, lead zircon titanate), and the drive electrodes 7 and 8 can be copper alloys. The material of the nozzle plate 11 will be described later. However, these materials are not limited to those illustrated, and various modifications can be made.

  As an example of the dimensions of the main part, the thickness of the nozzle body 2 is about 1 mm to several mm, the thickness of the nozzle plate 11 is about 50 μm to 100 μm, and the cross-sectional shape of the flow path 10 is about several mm in height (nozzle 2 The nozzle hole 12 that is a cylindrical opening has a diameter of about 20 μm to 50 μm, the pressure chamber 9 has a diameter of about 50 μm to 100 μm, and the flexible membrane 3 has a thickness of about 100 μm. The thickness of the piezoelectric element 4 can be about 30 μm. In the drawing, the cross-sectional shape of the flow path 10 is rectangular, but the shape is not limited thereto, and the corner may be rounded. These dimensions and shapes are not limited to those illustrated, and various modifications are possible.

  Next, the material of the nozzle plate 11 in which the nozzle holes 12 are processed will be described.

  The nozzle plate 11 is required to have high corrosion resistance due to the nature of the liquid to be discharged. Therefore, it is appropriately selected from a metal having corrosion resistance (for example, stainless steel), a resin (for example, polytetrafluoroethylene), ceramics (for example, alumina), and the like. In recent years, an ink jet method has been used in a film forming process of a liquid crystal display device or a semiconductor manufacturing device. When used in these applications, a hard fine particle (for example, silicon dioxide) is used as a liquid to be discharged. May be included. Therefore, the material of the nozzle plate 11 is required to have high wear resistance and toughness. Such a material having corrosion resistance, wear resistance, and toughness generally has poor workability, and it is difficult to ensure high processing accuracy and high productivity.

  Here, as a method for processing the nozzle hole 12, press processing, laser processing, electric discharge processing, etching processing, cutting processing, or the like can be considered. However, when the above-mentioned materials are pressed, there are problems such as cracking and chipping of the materials, removal of burrs and burrs after processing, and ensuring the accuracy of the roundness and linearity of the nozzle holes. In the case of laser processing, there are problems in that the processing material is limited and the accuracy of the roundness and linearity of the nozzle hole is ensured. In the case of electric discharge machining, there are problems that the machining time is long and the productivity is lowered, and that the heat at the time of machining is continuously received for a long time, so that the thermal stability is bad and the positional accuracy of the nozzle hole 12 cannot be ensured. When performing an etching process such as dry etching or wet etching, there is a problem that the cost of the equipment is higher than other processing methods, and in particular, the processing of holes with a high aspect ratio is expensive. When cutting with a drill or the like, it is easy to ensure the accuracy of the roundness and straightness of the nozzle hole, and the processing is low cost and the productivity is high. However, since the processing is fine, the tool (center drill) used for center hole processing is also thinned and the strength cannot be increased. Therefore, it is necessary to perform machining in consideration of the risk of tool breakage during center hole machining. Further, if there are burrs, chips, etc. accompanying the cutting at the inlet 12a, the operation characteristics such as landing characteristics and flight characteristics will be greatly affected.

  As described above, with the conventional processing technology, there are problems in ensuring elaborate and high processing accuracy for the nozzle hole 12 and ensuring high productivity. In particular, as described above, the nozzle plate 11 in which the nozzle hole 12 is processed is a serious problem because a material with poor processability is employed.

  The present inventor has obtained knowledge that such a problem unique to nozzle hole processing can be solved by adopting cutting as a method for processing the nozzle hole 12 and making the shape of the inlet 12a to be a pyramid. Moreover, the knowledge that it is more preferable to use a pyramid as a pyramid was also obtained.

  First, the shape of the inflow port 12a will be described by taking a case where the shape is a triangular pyramid as an example.

  3A and 3B are schematic views for explaining the shape of the inlet 12a. FIG. 3A is a plan view (a view of the inlet 12a seen from the pressure chamber 9 side), and FIG. It is BB sectional drawing of (a). The inlet 12a is provided on one end surface of the nozzle plate 11 and has a triangular pyramid shape. The inflow port 12a has a cross-sectional area that gradually decreases in the liquid discharge direction. A nozzle hole 12 communicates with one end of the inflow port 12a. The nozzle hole 12 is provided so that the position of the apex of the triangular pyramid is the center of the nozzle hole 12. Although processing of the inflow port 12a will be described later, the pyramid-shaped inflow port 12a is first processed, and then the nozzle hole 12 is processed. After the holes 12 are processed, the result is a truncated pyramid shape. Therefore, the plane of the truncated pyramid does not remain at the joint between the inlet 12a and the nozzle hole 12. In this case, strictly speaking, the shape of the inlet 12a is not a pyramid, but will be described as a pyramid. Note that electric discharge machining, plastic machining, or the like can be employed as a pyramid machining method. In particular, if plastic working is adopted, an excellent effect is produced, but details will be described later.

  Here, the inventor has found that it is appropriate to set the dimension L of the base of the triangular pyramid to 30% to 50% of the thickness of the nozzle plate 11. For example, if the thickness of the nozzle plate 11 is about 100 μm, the bottom dimension L is about 30 μm to 50 μm. In addition, the shape of the triangular pyramid in a figure is an illustration and other pyramids, such as a quadrangular pyramid, may be sufficient.

Next, the relationship between this pyramid and the processing accuracy of the nozzle hole 12 by cutting will be described.
In the conventional cutting process, in order to improve the run-out of the cutting tool (drill) and the so-called sticking property, a center hole process for forming a conical center hole is performed prior to the hole process. As a result of the study, the present inventor has found that if the nozzle hole 12 is processed using the conical center hole, the processing accuracy is deteriorated. This is considered to be because, when a conical center hole is used, the cutting tool transferred with a circular cross section hits the processing surface of the nozzle plate 11 almost once at the entire circumference, so that the processing accuracy deteriorates. . And the knowledge that the centripetality of a cutting tool (drill) is higher in the case of using a pyramid than in the case of using a cone was obtained. In particular, it was found that the triangular pyramid has the highest centripetal property and the machining accuracy of the nozzle hole 12 can be increased. Thus, if the inflow port 12a is a pyramid and this is the center hole when the nozzle hole 12 is processed, high processing accuracy can be ensured. This is particularly noticeable when the pyramid is a triangular pyramid.

Next, the operation of the inkjet head 1 will be described.
When a voltage is applied to the drive electrode 7 and the drive electrode 8, the upper member 5 undergoes a downward bending bending displacement, and accordingly, the laminated piezoelectric element 4 undergoes a downward bending bending displacement. This bending displacement pushes down the flexible film 3 downward as indicated by the wavy line in the drawing, and pressurizes the liquid in the pressure chamber 9 toward the nozzle hole 12. Therefore, a liquid corresponding to the bending displacement is discharged from the nozzle hole 12. The liquid reduced by the discharge is replenished from the liquid supply means (not shown) through the flow path 10. Since the bending displacement of the piezoelectric element 4 can be controlled by controlling the applied voltage, the applied amount can be controlled by a control device (not shown) to control the discharge amount. The bending displacement of the piezoelectric element 4 is absorbed by the flexible film 3, and mutual interference between adjacent piezoelectric elements and pressure chambers is prevented.

Next, a method for manufacturing the inkjet head 1 will be described.
FIG. 4 is a schematic diagram for illustrating the processing means 13 used for processing the nozzle body 2 and the nozzle plate 11.
An X-axis table 15 is provided on the upper surface of the frame 14, and a Y-axis table 16 is provided on the X-axis table 15. A rotary spindle 18 is provided on the Y-axis table 16 via a spacer 17, and a tool holding means 20 is provided on the rotary spindle 18. The tool 19 held by the tool holding means 20 can be changed by a tool changing means (not shown). A Z-axis table 21 is provided on the upper surface of the frame 14 so as to face the tool holding means 20, and a holding means 22 for holding the workpiece is provided on the Z-axis table 21. A foot 23 is provided on the lower surface of the frame 14.

  The X-axis table 15 has a function of moving the Y-axis table 16 in the X-axis direction in the figure, and the Y-axis table 16 has a function of moving the spacer 17 and the rotary spindle 18 in the Y-axis direction in the figure. The rotary spindle 18 has a function of rotating the tool 19 held by the tool holding means 20 and positioning and fixing the tool holding means 20 at a predetermined angle. The spacer 17 may have a function of preventing external vibration from being transmitted to the rotary spindle 18. The Z-axis table 21 has a function of moving the workpiece held by the holding means 22 in the Z-axis direction in the figure. The foot 23 has a function of preventing external vibration from being transmitted to the frame 14 and adjusting the upper surface of the frame 14 to be horizontal. The position control of the X-axis table 15, the Y-axis table 16, and the Z-axis table 21 and the rotation control of the rotary spindle 18 are performed by a control means (not shown).

  Note that the processing unit 13 illustrated in FIG. 4 is merely an example, and the processing unit 13 is not limited thereto, and a processing unit that performs the same function can be used.

As described above, electric discharge machining, plastic machining, or the like can be adopted as a method of machining the inlet 12a into a pyramid shape. Here, plastic machining will be described as an example.
FIG. 5 is a schematic diagram for illustrating a tool for processing the inlet 12a into a pyramid shape by plastic processing.
The tool 24 includes a cutting edge 25b having a pyramid shape at the tip of a tool shaft 25a. The tool shaft 25a is made of a metal such as carbon steel, and the cutting edge 25b is made of a hard material such as single crystal diamond. The blade edge 25b is brazed to one end surface of the tool shaft 25a. In addition, the above-mentioned materials, shapes, and blade edge fixing methods are not limited to these, and can be changed as appropriate.

  6 and 7 are process diagrams for explaining the manufacturing process of the ink jet head 1. It should be noted that the same parts as those in FIG.

  First, as shown in FIG. 6A, the outer periphery of the plate material is processed to create a so-called blank nozzle body 2.

  Next, as shown in FIG. 6B, the nozzle body 2 in the blank state is held by the holding means 22 of the processing means 13 described above, and the tool 19 a held by the tool holding means 20 is rotated by the rotary spindle 18. Thus, the flow path 10 is processed. As the tool 19a used at this time, a tool suitable for cutting a groove can be used. Further, the machining position is determined by the movement of the X-axis table, the Y-axis table, and the Z-axis table by a control means (not shown), and machining conditions such as the tool rotation speed are appropriately determined.

  Next, as shown in FIG. 6C, the pressure chamber 9 is processed by rotating the tool 19 b held by the tool holding means 20 with the rotary spindle 18. As the tool 19b used at this time, a tool suitable for making a hole can be used. Further, the processing position, processing conditions, and the like are appropriately determined in the same manner as described above. The tool 19b is exchanged by a tool exchange means (not shown).

  Next, as shown in FIG. 6D, instead of the nozzle body 2, a so-called blank nozzle plate 11 is held by the holding means 22 of the processing means 13 described above. Then, the tool 24 held by the tool holding means 20 is pushed into the nozzle plate 11 by a desired value, and the inlet 12a is formed by plastic working. At this time, the rotational direction position is adjusted by the rotary spindle 18 so that the direction of the blade edge 25b (pyramid) with respect to the nozzle plate 11 becomes a predetermined direction. After adjusting the rotational position, the rotary spindle 18 is fixed so as not to rotate. The direction of the blade edge 25b (pyramid) can be obtained by detecting the blade edge 25b with a detection means (not shown). The processing depth can be about 30% of the thickness of the nozzle plate 11. For example, if the thickness of the nozzle plate is about 100 μm, the height to the apex of the pyramid can be about 30 μm. However, these dimensions are not limited to those illustrated, and various changes can be made. For example, since the length of the nozzle hole 12 can be adjusted by adjusting the processing depth of the inflow port 12a, it is possible to selectively use according to operation characteristics such as landing characteristics and flight characteristics. The tool 24 is exchanged by a tool exchange means (not shown).

  If plastic processing in such a process is performed, burrs and chips associated with the cutting work are not generated in the inlet 12a portion as in the conventional conical center hole processing (cutting processing). For this reason, the processing of the inflow port 12a does not adversely affect the operation characteristics such as the landing characteristics and the flight characteristics. In addition, since the tool does not rotate, it is not affected by the runout during machining seen in the rotating tool (drill). Therefore, highly accurate processing is possible. Further, since the surface of the inlet 12a undergoes work hardening due to plastic working, the wear resistance of this portion is increased, and when the liquid contains hard fine particles (for example, silicon dioxide) as described above, the point of life is reached. In addition, an even better effect is produced. Further, in the conventional conical center hole machining, it was necessary to gradually process the center hole through several steps in order to avoid the risk of breakage of the center drill. An inlet 12a can be formed. Therefore, the processing time can be greatly shortened, and the productivity can be improved.

  Next, as shown in FIG. 6 (e), the tool 19 c held by the tool holding means 20 is rotated by the rotary spindle 18 to drill the nozzle hole 12. At this time, the deflection of the tool 19c is suppressed by the centripetal action of the pyramidal inlet 12a, and the so-called sticking is improved, so that the machinability at the beginning of machining is also improved. After the nozzle hole 12 is drilled, the deburring of the nozzle opening 12b and removal of machining waste are performed. The tool 19c is exchanged by a tool exchange means (not shown).

  By performing the cutting process in such a process, an excellent nozzle hole 12 having higher roundness, linearity, dimensional accuracy, position accuracy, etc. is obtained than in the case of cutting using a conventional conical center hole. Can do. This also solves the problems that the conventional cutting has, and can enjoy the advantages such as machining accuracy and productivity that the cutting has.

  Next, as shown in FIG. 7A, the nozzle plate 11 that has been subjected to nozzle hole processing is fixed to the nozzle body 2 that has been processed in FIG. For fixing, an epoxy adhesive, brazing, screwing, diffusion bonding, or the like can be used.

  Next, as shown in FIG. 7B, the flexible film 3 is installed on the upper surface of the flow path 10 of the nozzle body 2.

  Next, as shown in FIG. 7C, the piezoelectric element 4 is installed on the upper surface of the flexible film 3. At this time, the piezoelectric element 4 is installed directly above the pressure chamber 9. In addition, the piezoelectric element 4 is manufactured in advance by laminating the lower member 6, the drive electrode 7, the upper member 5, and the drive electrode 8 in this order and then firing them integrally.

Next, an ink jet head manufacturing method according to the second embodiment of the present invention will be described.
FIG. 8 is a process diagram for explaining a manufacturing process of the inkjet head 1. In the present embodiment, the nozzle plate 31 is formed by plating (film formation) by electroless plating, and then the processing of the nozzle body 2 (processing of the flow path 10 and the pressure chamber 9), the inlet 12a of the nozzle hole 12 The processing is different from the specific examples shown in FIGS. The same parts as those shown in FIG. 6 and FIG.
First, as shown in FIG. 8A, the outer periphery of the plate material is processed, and the so-called blank nozzle body 2 is created.

  Next, as shown in FIG. 8 (b), an amorphous nickel (nickel-phosphorus) alloy is plated (film-formed) on one end surface of the nozzle body 2 in a blank state by an electroless plating method to form a nozzle plate 31. Let Thus, if the nozzle plate 31 is made of an amorphous alloy, very high corrosion resistance and wear resistance can be obtained. The contents of plating, pre-treatment, and post-treatment will be described later.

  Next, as shown in FIG. 8C, the flow path 10, the pressure chamber 9, the inlet 12a, and the nozzle hole 12 are sequentially processed. Each processing is the same as that shown in FIGS.

  Next, as shown in FIG. 8D, the flexible film 3 is adhered to the upper surface of the flow path 10 of the nozzle body 2 so as to be liquid-tight with an epoxy adhesive, and the piezoelectric film is bonded to the upper surface of the flexible film 3. The element 4 is bonded with an epoxy adhesive. This procedure is similar to that described above with respect to FIGS.

  When the inkjet nozzle 1 is manufactured by such a procedure, the electroless plating (film formation) is performed at the first stage to form the nozzle plate 31, and thereafter, the consistent flow path 10, the pressure chamber 9, the inlet 12a, Since the nozzle hole 12 can be processed, it is not necessary to change the setup (attachment or removal of the workpiece), and there are no problems such as misalignment, deflection, and exchange time associated with the setup change. Therefore, high machining accuracy and productivity can be ensured accordingly. In addition, the electroless plating can provide a much higher peel strength of the nozzle plate 31 than the case of bonding. If the plated surface is roughened by blasting or the like, it can be made more difficult to peel. In addition, the liquid-tightness is much higher than that in the case of excellent adhesion and adhesion.

Next, the aforementioned electroless plating method will be described.
In this electroless nickel plating, for example, sodium hypophosphite is used as a reducing agent, and nickel ions are reduced by the reducing action of hypophosphite ions and deposited on the object to be plated. As a pretreatment for electroless plating, masking, degreasing, cleaning, etc. on surfaces other than the plating surface are performed. Further, it is desirable to roughen the plated surface by blasting or the like (provide fine irregularities). By electroless plating, the peel strength of the nozzle plate 31 is much higher than in the case of bonding. However, if the plated surface is roughened, the nozzle plate 31 is more difficult to peel due to the so-called anchor effect. Because it becomes. Further, the liquid-tightness is much higher than in the case of excellent adhesion and adhesion. As post-processing, the mask is removed and washed, and if necessary, the surface 28 of the nozzle plate 31 is processed to be flat. This processing can be performed by the processing means 13 described above.

  For film formation, vapor deposition, electroplating, thermal spraying, and the like can also be employed.

  Next, an ink jet head and a method for manufacturing the same according to a third embodiment of the present invention will be described.

  FIG. 9 is a schematic cross-sectional view for illustrating the configuration of a thermal inkjet head that discharges liquid by heating. The same parts as those in FIG. 2 are denoted by the same symbols, and only different parts will be described.

  In the inkjet head 32, a protective film 34 is installed on the flow path 10 of the nozzle body 2, and a heating element 33 is installed on the protective film 34. The heating element 33 is formed of a resistive thin film made of an electrical resistance material, and generates Joule heat when power is supplied from a power supply means (not shown). The protective film 34 is made of an inorganic material such as silicon oxide or silicon nitride. The protective film 34 can be about 2 μm thick, and the heating element 33 can be about 3 μm thick. However, these arrangements, shapes, dimensions, and materials are not limited to those illustrated in FIG. 9, and various changes can be made.

  Next, the operation will be described. Electric power is supplied from a power supply means (not shown) to the heating element 33 to cause the heating element 33 to generate heat. Bubbles 35 are generated in the liquid by the heat generated by the heating element 33. The liquid in the pressure chamber 9 is pressurized toward the nozzle hole 12 by the pressure of the generated bubbles 35. A liquid corresponding to the pressure is discharged from the nozzle hole 12. The liquid reduced by the discharge is replenished from the liquid supply means (not shown) through the flow path 10. The generated bubbles 35 disappear so that the surrounding liquid takes heat and contracts, and wait for the next heat generation and generation of bubbles. If the supply power is controlled in this series of steps, the size of the bubbles 35 and the timing of their generation can be controlled. Therefore, if the supply power is controlled by a control device (not shown), the discharge amount and the discharge timing can be controlled. .

  The manufacturing method of the ink-jet head 32 is the same as that shown in FIGS. 6 to 8 except that the flexible film 3 is replaced by the protective film 34 and the piezoelectric element 4 is replaced by the heat generating element 33, and the description thereof will be omitted.

  As described above, as can be understood from the above description, according to the present invention, there are provided an ink jet head and an ink jet head manufacturing method that have good operational characteristics such as landing characteristics and flight characteristics and excellent productivity.

  Although the present invention has been described with reference to specific examples, the present invention is not limited to these specific examples. Regarding the ink jet head according to the above-described specific example and the method for manufacturing the ink jet head, those appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the present invention can be applied not only to a multi-nozzle ink jet head but also to an ink jet head having a single nozzle hole, and the use of the ink jet head is not limited to the above-described specific examples. The flexible film 3 is not limited to the illustrated resin film, and any material such as a metal film may be used as long as the flexible film 3 can shield the discharged liquid from penetrating the piezoelectric element 4 and has flexibility. . The piezoelectric element 4 is not limited to the two-layer structure, and may be three or more layers, and the material is not limited to the exemplified one. Further, it may not be an integrally fired laminated piezoelectric element. The pressure element 4 and the flexible film 3, and the flexible film 3 and the nozzle body 2 can be bonded using an epoxy adhesive. The protective film 34 is not limited to the exemplified inorganic material as long as it can shield the discharged liquid from penetrating the heating element 33 and has heat resistance. As the installation method of the heat generating element 33 and the protective film 35 and the protective film 35 and the nozzle body 2, an installation method by bonding with an epoxy adhesive or the like can also be used. In addition, the type and conditions of electroless plating can be changed as appropriate. The adhesion between the nozzle body 2 and the nozzle plate 11 is not limited to the illustrated epoxy adhesive, but may be brazing or diffusion bonding.

It is a schematic diagram for demonstrating the external appearance of an inkjet head. It is a model enlarged view of the AA direction cross section of FIG. It is a schematic diagram for demonstrating the shape of an inflow port. It is a schematic diagram for illustrating the processing means used for processing of a nozzle body and a nozzle plate. It is a schematic diagram for illustrating the tool which processes an inflow port into a pyramid shape by plastic working. It is process drawing for demonstrating the manufacturing process of an inkjet head. It is process drawing for demonstrating the manufacturing process of an inkjet head. It is process drawing for demonstrating the manufacturing process of an inkjet head. FIG. 2 is a schematic cross-sectional view for illustrating the configuration of a thermal type ink jet head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head, 2 Nozzle body, 9 Pressure chamber, 11 Nozzle plate, 12 Nozzle hole, 12a Inlet, 32 Inkjet head, 31 Nozzle plate

Claims (7)

A nozzle body having a pressure chamber for pressurizing the liquid;
A nozzle plate having nozzle holes for discharging pressurized liquid;
With
An ink jet head characterized in that a pyramid-shaped inlet is provided between the pressure chamber and the nozzle hole in a direction in which a cross-sectional area decreases toward the nozzle hole.   The inkjet head according to claim 1, wherein the pyramid is a triangular pyramid.   The inkjet head according to claim 1, wherein the pyramid is formed by plastic processing.   The inkjet head according to claim 1, wherein the nozzle plate is formed by forming a film on one end face of a nozzle body. Forming a pyramid-shaped inlet so that the cross-sectional area decreases from the pressure chamber toward the nozzle hole;
Processing the nozzle hole using the pyramidal inlet as a center hole;
An ink jet head manufacturing method comprising:   6. The method of manufacturing an ink jet head according to claim 5, wherein the pyramid is a triangular pyramid.   6. The method of manufacturing an inkjet head according to claim 5, wherein the step of forming the inflow port having the pyramid shape is performed by plastic working.

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