JP2007247806A - Method for forming hydrodynamic pressure generating portion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a machining cost by simplifying a process for forming a hydrodynamic pressure generating portion. <P>SOLUTION: When the hydrodynamic pressure generating portion is formed in the clearance of a bearing, first, ink 12 is supplied on the surface of a blank 2a' so as to form a masking pattern 1 corresponding to the shape of the hydrodynamic pressure generating portion with the aggregate of a very small amount of the ink. Next, the surface of the blank at the non-masking portion 1b is removed by chemical etching so as to have a surface roughness Ra of within 0.3 μm. After that, the masking pattern 1 is removed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for forming a dynamic pressure generating portion provided on an outer periphery and an end surface of a shaft member used in a dynamic pressure bearing device.

    The hydrodynamic bearing device generates pressure by the dynamic pressure action of the lubricating oil generated in the bearing gap by the relative rotation of the shaft member and the bearing member located on the outer periphery of the shaft member, and the shaft member is supported in a non-contact manner by this pressure. It is a bearing device. This hydrodynamic bearing device has characteristics such as high-speed rotation, high rotation accuracy, and low noise. Recently, by utilizing the characteristics, information devices such as magnetic disk devices such as HDD and FDD, CD-ROM, Bearings for spindle motors such as optical disk devices such as CD-R / RW and DVD-ROM / RAM, magneto-optical disk devices such as MD and MO, bearings for polygon scanner motors of laser beam printers (LBP), or electrical equipment The application is expanding as a bearing for a small motor such as a color wheel of a projector, an axial fan, or the like.

  In this type of hydrodynamic bearing device, for example, hydrodynamic grooves arranged in a herringbone shape, a spiral shape, or the like are formed on the outer peripheral surface of the shaft member. The following method is known as a method for accurately forming the dynamic pressure generating portion having a special and complicated shape.

  (1) A film for masking is formed on the surface of the shaft member, and after removing a portion corresponding to the dynamic pressure groove of the film with a laser beam, the dynamic pressure groove is formed through an etching process and a film removal operation. (For example, refer to Patent Document 1).

(2) The printing mold corresponding to the dynamic pressure groove shape is moved in accordance with the rotation of the shaft member while being in contact with the material outer peripheral surface of the shaft member, so that portions other than the dynamic pressure groove are corrosion-resistant on the shaft member material outer periphery. While printing with ink, light is irradiated to positions other than the contact part with the printing type | mold of a shaft member, and ink is hardened. Thereafter, the non-printing portion is etched and the printing portion is removed to form a dynamic pressure groove (see, for example, Patent Document 2).
JP 2001-200400 A Japanese Patent Publication No.62-49351

  According to the method for forming a dynamic pressure generating part of (1) above, after a film layer made of an organic binder (ink) is formed over the entire surface of the dynamic pressure generating part forming area, the film removal for forming a dynamic pressure groove by laser light ( Patterning), the amount of ink used and the formation process increase, and a laser beam irradiation facility is required, which increases costs and requires a large investment.

  On the other hand, according to the above method (2), since the printing mold moves in contact with the outer peripheral surface of the shaft member, wear at the contact portion is likely to occur, and in mass production, the printing accuracy due to wear or deformation of the printing mold is increased. There is concern about the decline. Furthermore, the corrosion-resistant ink supplied from the ink supply device reaches the outer peripheral surface of the shaft member through the printing die, and is further compressed by the squeegee to be fixed on the outer peripheral surface of the shaft member. This is uneconomical due to the increased use of expensive anticorrosive inks. In addition, since a printing mold corresponding to the dynamic pressure groove and the material shape is required, it is difficult to meet various recent demands.

  An object of the present invention is to simplify the process of forming a dynamic pressure generating portion for generating a dynamic pressure action including a dynamic pressure groove, and to reduce the processing cost.

  In order to solve the above problems, in the present invention, when forming a dynamic pressure generating portion for generating a dynamic pressure action in the bearing gap on the surface of the shaft member, ink is supplied to the material surface of the shaft member, A masking pattern corresponding to the shape of the dynamic pressure generating part is formed with the aggregate of ink, and the material surface of the non-masking part is removed by chemical etching so that the surface roughness is within Ra 0.3, and then the masking pattern is removed. A method for forming a dynamic pressure generating portion is provided.

  According to this method, a highly accurate masking pattern can be formed, while the nozzle and the surface of the material are not in contact with each other, so that a decrease in accuracy due to wear at the contact portion, which is a problem in the conventional method, can be avoided. Further, since this method does not require a squeegee and ink is used only at a necessary location, the amount of ink used is sufficient to contribute to the formation of the masking pattern, and the amount of ink used can be reduced. Furthermore, there is no need for a printing mold, a holding member for holding the printing mold, or a masking pattern molding process for a film covering the surface of a material, which has been necessary in conventional methods, and the molding apparatus can be simplified. Cost reduction can be achieved.

  When the material surface of the non-mask portion is removed by chemical etching, the surface roughness of the removed portion during the etching is maintained substantially constant. If etching is performed so that the surface roughness of the removed portion (centerline average roughness specified in JIS B0601) is within Ra0.3, for example, a large amount of shaft members are accommodated in a rotating tank or a vibrating tank and etched simultaneously. Even in this case, it is possible to prevent a situation in which the edge of the removed portion scrapes the mask and lowers its masking function. As a result, the shaft member can be etched in a large amount, and the production cost of the shaft member can be reduced. Moreover, if it is within Ra0.3, even when the bearing is used, it is possible to avoid a situation in which the bottom portion of the dynamic pressure generating portion comes into contact with and damages the opposing member facing it, and the predetermined dynamic pressure effect is stable. Is obtained.

  A surface roughness of Ra 0.3 or less can be obtained by using a 46 ± 2 Be ′ solution of ferric chloride as an etching solution.

  For the ink that forms the masking pattern, a resin that can be cured by applying various energy can be used. However, considering the cost and work environment, a photo-curable resin is used, and this resin is cured by irradiation with light. Is preferred. As the photocurable resin, a visible light curable resin and the like can be used in addition to the ultraviolet curable resin and the infrared curable resin, but an ultraviolet curable resin that can be cured at a low cost and in a short time is particularly preferable.

The method for forming the dynamic pressure generating portion described above can be applied not only when forming the dynamic pressure generating portion on the end surface of the shaft member but also on the outer periphery of the shaft member.

  According to the present invention, the forming process of the dynamic pressure generating portion can be simplified, and the processing cost can be reduced. In addition, since a large amount of etching can be performed, the manufacturing cost of the shaft member can be reduced and the cost of the hydrodynamic bearing device can be reduced.

  Hereinafter, an embodiment of the method of the present invention will be described with reference to FIGS.

  The method of the present invention comprises a first step of forming a masking pattern on the surface of the material, a second step of removing the non-mask portion by chemical etching, and a third step of removing the masking pattern.

  FIG. 1 shows the first step, and an apparatus for forming a masking pattern by supplying a resin composition to the outer periphery of a material 2a ′ of a shaft portion 2a constituting a shaft member 2 (see FIG. 6), here an inkjet 1 shows an outline of a printing apparatus of the type. The material 2a 'is formed of a metal material such as stainless steel. As shown in the figure, this printing apparatus is arranged with one or a plurality of nozzle heads 10 opposed to the outer peripheral surface 2a1 of the rotationally driven material 2a ′ and the circumferential positions of the nozzle heads 10 different from each other. The hardened part 3 is a main component. The nozzle head 10 is provided with a plurality of nozzles 14 for discharging ink 12 in a microdroplet state in the axial direction. The ink 12 has etching resistance. For example, a photo-curable ink, preferably an ultraviolet curable ink using an ultraviolet curable resin as a base resin is used. If necessary, an organic solvent is blended in an appropriate ratio. The curing unit 3 is a light source that irradiates light for curing the resin composition, and for example, an ultraviolet lamp is used.

  Examples of the base resin of the ultraviolet curable ink include radical polymerizable monomers, radical polymerizable oligomers, cationic polymerization monomers, imide acrylates, and ene / thiol compounds represented by cyclic polyene compounds and polythiol compounds. Among these, radical polymerizable monomers, radical polymerizable oligomers, and cationic polymerization monomers can be preferably used. As the radical polymerizable monomer, for example, a monofunctional, bifunctional or polyfunctional acrylate monomer or methacrylate monomer can be used, and as the radical polymerizable monomer, for example, urethane acrylate, epoxy acrylate, polyester acrylate, or unsaturated. Polyester can be used. Examples of the cationic polymerization monomer include bisphenol A epoxy resin, phenol novolac epoxy resin, alicyclic epoxy resin, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3- Ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3- (2-ethylhexyl) Oxetane resins such as siloxymethyl) oxetane and 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane can be used. These ultraviolet curable resins can be used alone, or a mixture of two or more types can be used as the base resin.

  These base resins are blended with a photopolymerization initiator such as a radical photopolymerization initiator for causing a polymerization reaction by ultraviolet irradiation or a cationic photopolymerization initiator. Examples of radical photopolymerization initiators include hydrogen represented by benzophenone, methyl orthobenzoin benzoate, 4-benzoyl-4′-methyldiphenyl sulfide, ammonium salt of benzophenone, isopropylthioxanthone, diethylthioxanthone, and ammonium salt of thioxanthone. Pull-out photopolymerization initiators can be used, or benzoin derivatives, benzyldimethyl ketal, α-hydroxyalkylphenone, α-aminoalkylphenone, acylphosphine oxide, monoacylphosphine oxide, bisacylphosphine oxide, acrylphenylglycol Intramolecular cleavage type photopolymerization initiators typified by oxylate, diethoxyacetophenone and titanocene compounds can be used. Examples of the cationic photopolymerization initiator include triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, SP-170 and SP-150 (both manufactured by Asahi Denka Co., Ltd.), FC-508, Polyarylsulfonium salts exemplified by FC-512 (both manufactured by 3M Company), UVE-1014 (manufactured by General Electric Company), triallyl sulfone exemplified by Uvacure 1590 and Uvacure 1591 (both manufactured by Daicel UCB) Mixtures of muhexafluorophosphade salts, metallocene compounds exemplified by Irg-261 (Ciba Geigy), diphenyliodonium hexafluoroantimonate and P-nonylphenylphenyliodonium Kisa hexafluoroantimonate, poly aryl iodonium salts such as 4,4'-diethoxy-phenyl iodonium hexafluoroantimonate can be used. These photopolymerization initiators can be used alone or in combination of two or more.

  In the above examples, the ultraviolet curable type is exemplified as the ink, but a thermosetting type ink can also be used.

  The nozzle head 10 is reciprocally slid in the axial direction while rotating the material 2a ′ while supporting the material 2a ′ at both ends by the support unit 13, and the ink 12 is ejected from the nozzles 14, whereby the fine droplets of the ink 12 become the outer periphery of the material 2a ′. Lands at a predetermined position on the surface 2a1. By gathering a large number of these fine droplets, a mask portion (maskant) 1a is formed on the outer peripheral surface 2a1 of the material 2a ', and a masking pattern 1 is formed by the mask portion 1a and the non-mask portion 1b. The masking pattern 1 is printed in such a manner that it gradually advances in the circumferential direction as the shaft member 2 rotates. When the printed portion reaches the opposite area of the cured portion 3, the ink 12 that has been irradiated with ultraviolet rays is polymerized. Causes reaction and cures sequentially. Finally, the masking pattern 1 is formed on the entire circumference of the material 2a 'by rotating the material 2a' one to several tens of times while appropriately switching the supply / stop of ink from each nozzle. As shown in FIG. 2A, the printed masking pattern 1 forms a concavo-convex cross section with a mask portion 1a and a non-mask portion 1b raised from the surface of the material.

  FIG. 3 also shows the first step, and shows an outline of an ink jet printing apparatus that forms a masking pattern on the upper end surface 2b1 or lower end surface 2b2 of the material 2b ′ of the flange portion 2b constituting the shaft member 2. (When it is formed on the lower end surface 2b2, it is exactly the same as the case of forming on the upper end surface 2b1, except for the difference between the upper and lower sides, so the description is omitted below). The main components are the same as those of the printing apparatus of FIG. 1, except that the nozzle head 10 and the curing unit 3 are arranged to face the upper end surface 2b1 of the material 2b ′ to be rotationally driven, and the nozzle head 10 and the hardened portion 3 are arranged at different positions in the circumferential direction on the upper end surface 2b1.

  In the printing apparatus described above, the ink film thickness after printing and the shape of the masking pattern can be accurately managed by controlling the ejection of the fine droplets of the ink 12. Therefore, as compared with the conventional case where the masking layer is formed over the entire surface of the pattern formation region, the amount of ink 12 used is sufficient to be involved in the formation of the masking pattern 1, and a masking pattern formation step using a laser or the like is unnecessary. Thus, since the printed masking pattern 1 can be used as it is and the etching process can be performed, the manufacturing cost can be reduced.

  Further, in the masking pattern forming method according to the present invention, since there is no contact portion between the printing mold and the shaft member 2 as in a conventional printing machine, it is possible to avoid a decrease in printing accuracy due to wear at the contact portion. The masking pattern accuracy can be secured stably even during mass production. Further, since the printing mold and the printing screen for holding the printing mold are not necessary, and the mechanism for moving the printing mold in accordance with the rotation of the shaft member 2 is not necessary, the structure of the printing apparatus is simplified. Can do. Further, similarly to the above, since the amount of ink 12 used is sufficient to be involved in the formation of the masking pattern 1, the amount of ink 12 used is reduced and the cost is reduced as compared with the conventional device that requires a squeegee. be able to.

  As a fixing method of the ink 12, not only the above-described ink jet method but also a method of discharging droplets using electrophoresis, a so-called nozzleless type droplet discharging method, or the ink 12 via a micropipette. Can be used instead of droplets in a continuous manner on the surface of the material 2a ', or a method in which the distance to the material surface is shortened and the ink 12 is brought into contact with the fixing surface simultaneously with the ejection. Moreover, the printing method of an inkjet printer may be either a continuous (continuous) type or an on-demand type.

  After forming the masking pattern in the first step, the material 2a 'is transferred to the second step.

  As shown in FIG. 2B, in the second step, the surface of the non-mask portion 1b of the outer peripheral surface 2a1 is removed by a prescribed depth (several μm) by chemical etching. In the case of electrolytic etching, an electrolytic power source is required, and the processing apparatus becomes expensive and complicated. However, chemical etching can solve these problems.

  When etching the non-mask portion 1b, the surface roughness of the etched surface during the etching is kept substantially constant. If the surface roughness of the etched surface at this time is within Ra 0.3, for example, even when a large amount of material 2a ′ is placed in a rotating tank or a vibrating tank and barrel processing is performed during etching, the edge of the etched surface is It is possible to prevent a situation in which the masking function of the other material 2a ′ is reduced by cutting the mask portion 1a. As a result, the material 2a 'can be etched in a large amount, and the manufacturing cost of the shaft member can be further reduced. Moreover, if it is within Ra0.3, even when the bearing is used, it is possible to avoid a situation in which the bottom portion of the dynamic pressure generating portion comes into contact with and damages the opposing member facing it, and the predetermined dynamic pressure effect is stable. Is obtained. A surface roughness within Ra 0.3 can be obtained by using, for example, a ferric chloride solution having a specific gravity of 40 to 50 Be ′, preferably about 46 ± 2 Be ′ as an etching solution.

  Finally, the material 2a 'is transferred to the third step, and after washing the material 2a' with water, the mask portion 1a is removed by swelling or peeling with an organic solvent such as a dichloromethane solution. As a result, as shown in FIG. 2C, a dynamic pressure groove generating portion A is formed which includes the dynamic pressure groove Ab and a portion (partition portion) Aa for partitioning and forming the dynamic pressure groove Ab.

  Since the procedure is exactly the same, a detailed description is omitted, but the upper side of the material 2b ′ of the flange portion 2b is the same as described above based on FIGS. 2 (a) to 2 (c). For example, a dynamic pressure generating portion B composed of a dynamic pressure groove Bb and a partition portion Ba arranged in a spiral shape shown in FIG. 4 is formed on the end surface 2b1, and further, for example, a spiral-shaped dynamic pressure groove and a partition portion are formed on the lower end surface 2b2. A dynamic pressure generating part C (not shown) is formed. One or both of the dynamic pressure generating parts B and C can be formed by press working.

  In this way, the shaft member 2 shown in FIGS. 5 and 6 is obtained by integrating the shaft portion 2a formed with the dynamic pressure generating portions A, B, and C and the flange portion 2b by a method such as press fitting. In addition, the material 2a ′ of the shaft portion 2a and the material 2b ′ of the flange portion 2b are integrally formed by forging or the like in advance, and this is sequentially supplied to the first-stage printing apparatus shown in FIGS. After forming, the shaft member 2 can also be formed through the second step and further the third step. In this case, since the etching process can be performed simultaneously on the shaft portion 2a and the flange portion 2b, the dynamic pressure grooves can be formed more efficiently.

  FIG. 5 shows a configuration example of the hydrodynamic bearing device 21 in which the shaft member 2 manufactured in the above process is incorporated. This hydrodynamic bearing device 21 has a shaft member 2, a sleeve-like portion, a bearing member 7 in which the shaft portion 2 a can be inserted into the inner periphery, and a lid member 8 that seals one end side opening of the bearing member 7. And a seal portion 9 for sealing the lubricating oil which is located on the other end side of the bearing member 7 and fills the inside of the hydrodynamic bearing device 21.

  The bearing member 7 is formed in a substantially cylindrical shape, and the shaft member 2 is inserted into the inner periphery thereof. The bearing member 7 in the illustrated example includes a sleeve portion 7a, an upper seal mounting portion 7b, and a lower sealing portion 7c. The inner peripheral surface 7c1 of the sealing portion 7c is separate from the bearing member 7. A lid member 8 to be described later is fitted and fixed. The cylindrical inner peripheral surface 7a1 of the sleeve portion 7a is smaller in diameter than the inner peripheral surface 7b1 of the seal mounting portion 7b and the inner peripheral surface 7c1 of the sealing portion 7c, and faces the two dynamic pressure generating portions A of the shaft member 2. .

  The lid member 8 is a member that seals one end opening of the bearing member 7, and is formed in a bottomed substantially cylindrical shape that is separate from the bearing member 7. The lid member 8 includes a cylindrical side portion 8a and a bottom portion 8b that seals a lower end opening of the side portion 8a. In the illustrated example, the side portion 8a and the bottom portion 8b are integrally formed. For example, the lid member 8 is fitted to the bearing member 7 by fitting the inner circumferential surface 8a1 of the side portion 8a to the inner circumferential surface 7c1 of the sealing portion 7c of the bearing member 7 and applying appropriate means such as press-fitting, adhesion, and welding. Fixed. The upper end surface 8a2 of the side portion 8a of the lid member 8 is in contact with the lower end surface 7a2 of the sleeve portion 7a of the bearing member 7, whereby the thrust bearing gap is managed to a specified width.

  The seal portion 9 is formed in an annular shape with a metal material or a resin material. In this embodiment, the seal portion 9 is formed separately from the bearing member 7, and is fixed to the inner peripheral surface 7b1 of the seal mounting portion 7b located on the upper end side of the bearing member 7 by means such as press-fitting and bonding. . The inner peripheral surface 9a of the seal portion 9 increases in a taper shape toward the upper side. Between the inner peripheral surface 9a and the outer peripheral surface 2a1 of the shaft portion 2a facing the inner peripheral surface 9a, there is an upward direction. An annular seal space S in which the radial dimension gradually increases as it goes to is formed. Lubricating oil is injected into the internal space of the hydrodynamic bearing device 1 sealed by the seal portion 9, and the interior of the hydrodynamic bearing device 1 is filled with the lubricating oil. In this state, the oil level of the lubricating oil is maintained within the range of the seal space S. In order to reduce the number of parts and the number of assembly steps, the seal portion 9 can be integrally formed with the bearing member 7.

  In the dynamic pressure bearing device 21 having the above-described configuration, when the shaft member 2 is rotated, a space between the dynamic pressure groove generating portion A formed on the outer peripheral surface 2a1 of the shaft portion 2a and the inner peripheral surface of the bearing member 7 facing the same. A radial bearing gap is formed on the surface. Further, a first thrust bearing gap is formed between the dynamic pressure generating portion B formed on the upper end surface 2b1 of the flange portion 2b and the lower end surface 7a2 of the bearing member 7 opposed to the dynamic pressure generating portion B, and the flange portion 2b A second thrust bearing gap is formed between the dynamic pressure generating portion C formed on the lower end surface 2b2 and the upper end surface 8b1 of the lid member 8 facing the dynamic pressure generating portion C. Then, a dynamic pressure action is generated in the lubricating oil filled in the radial bearing gap and the thrust bearing gap, and thereby radial bearing portions R1 and R2 for supporting the shaft member 2 in a radial direction in a non-contact manner are formed in the radial bearing gap. Thrust bearing portions T1 and T2 for supporting the shaft member 2 in a non-contact manner in the thrust direction are formed in the thrust bearing gap.

  One or both of the dynamic pressure generating parts B and C are formed on a member facing both end faces 2b1 and 2b2 of the flange part 2b, for example, the lower end face 7a2 of the bearing member 7 and the upper end face 8b1 of the lid member 8. You can also

  FIG. 6 shows another configuration example of the hydrodynamic bearing device 21 using the shaft member 2. The dynamic pressure bearing device 21 is greatly different from the first configuration example shown in FIG. 5 in that the bearing member 7 which is a single member is composed of two members, a housing 17 and a bearing sleeve 18. The bearing sleeve 18 is formed in a cylindrical shape, for example, with oil-impregnated sintered metal. The housing 7 is formed into a substantially cylindrical shape by, for example, resin injection molding, and the bearing sleeve 18 is fixed to the inner peripheral surface thereof by means such as adhesion. When the shaft member 2 rotates, a radial bearing portion is formed in the radial bearing gap between the dynamic pressure generating portion A formed on the outer peripheral surface 2a1 of the shaft member 2 and the inner peripheral surface of the bearing sleeve 18 facing the dynamic pressure generating portion A. The Since the other points have the same structure, the same reference numerals are given and the duplicate description is omitted.

  In the above description, the dynamic pressure generating portions constituting the radial bearing portions R1, R2 and the thrust bearing portions T1, T2 are exemplified by, for example, a plurality of dynamic pressure grooves arranged in a herringbone shape or a spiral shape. The configuration of the pressure generating unit is not limited to this. As the radial bearing portions R1, R2, for example, so-called multi-arc bearings in which the radial bearing gap is reduced in a wedge shape in one or both of the circumferential directions at a plurality of locations in the circumferential direction, or in the axial direction A so-called step bearing in which extended dynamic pressure grooves are formed at a plurality of locations in the circumferential direction can also be used. Further, as the thrust bearing portions T1 and T2, a so-called step bearing, a so-called corrugated bearing (the corrugated step mold) having a plurality of radial groove-shaped dynamic pressure grooves provided at equal intervals in the circumferential direction, etc. Can also be configured. 5 and 6 exemplify a case where two radial bearing portions R1 and R2 are arranged apart from each other in the axial direction, the number of radial bearing portions is arbitrary, and one or three or more. It can also be provided.

It is a side view which shows the printing apparatus of a masking pattern. It is an expanded sectional view showing the formation process of a dynamic pressure generating part. It is a side view which shows the other example of the printing apparatus of a masking pattern. It is a top view which shows an example of the dynamic pressure generation part formed in the end surface of a shaft member. It is sectional drawing which shows the structural example of a hydrodynamic bearing apparatus. It is sectional drawing which shows the structural example of a hydrodynamic bearing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Masking pattern 1a Mask part 1b Non-mask part 2 Shaft member 2a Shaft part 2b Flange part 3 Hardening part 7 Bearing member 8 Lid member 10 Nozzle head 12 Ink (resin composition)
13 Supporting part 14 Nozzle 21 Dynamic pressure bearing device A, B, C Dynamic pressure generating part R1, R2 Radial bearing part T1, T2 Thrust bearing part

Claims (3)

When forming a dynamic pressure generating portion for generating a dynamic pressure action in the bearing gap on the surface of the shaft member,
Ink is supplied to the material surface of the shaft member, and a masking pattern corresponding to the shape of the dynamic pressure generating part is formed by a collection of a small amount of ink, and the material surface of the non-mask part is subjected to chemical etching within a surface roughness Ra of 0.3. And then removing the masking pattern. A method for forming a dynamic pressure generating portion, wherein:   The method for forming a dynamic pressure generating portion according to claim 1, wherein the ink is a photocurable material.   The method for forming a dynamic pressure generating portion according to claim 1, wherein a 46 ± 2Be 'solution of ferric chloride is used as an etching solution.

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