JP2009208404A - Method for manufacturing nozzle plate and liquid jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a nozzle plate wherein a punch hardly breaks even if it has a two-stepped nozzle opening. <P>SOLUTION: The method for manufacturing a nozzle plate comprises: a first prepared hole forming process for forming a first prepared hole 40 having a bottom in a metal sheet 31 by driving a first punch 36 to an intermediate portion of the metal sheet in the sheet thickness direction from one surface of the metal sheet toward the other surface; a second prepared hole forming process for forming a second prepared hole 42 narrower than the first prepared hole in the bottom of the first prepared hole by driving a second punch 50 narrower than the first punch from one surface of the metal sheet where the first prepared hole is formed, and for forming a swollen part 52 on the other surface of the metal sheet; and a penetration process for forming the nozzle opening by grinding the other surface of the metal sheet where the first prepared hole and the second prepared hole are formed, and by removing the swollen part to sequentially penetrate both of the prepared holes. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a nozzle plate provided in a liquid ejecting apparatus such as an ink jet recording apparatus, and a liquid ejecting head equipped with the nozzle plate.

  A nozzle plate of a liquid ejecting head such as an ink jet recording apparatus that ejects liquid droplets from a nozzle opening by causing a pressure fluctuation in a liquid in a pressure chamber is a silicon wafer or a thin metal plate (for example, Stainless steel plate) has a plurality of fine-diameter through holes. As a method for opening a through hole in a silicon wafer, there is a method by dry etching, and as a method for opening a through hole in a metal plate, there is a press working (plastic working) method using a mold.

In the case where the through hole serving as the nozzle opening is a stepped hole in which a large hole and a small hole are connected in series, the silicon wafer is formed by dry etching (see, for example, FIG. 4 of Patent Document 1).
On the other hand, in the case of press working, generally, a punch is pushed in from one surface of a thin metal plate that becomes a nozzle plate, and the protruding portion protruding to the opposite side is removed in a subsequent polishing step, thereby the nozzle opening. A method of opening a through hole is proposed (for example, Patent Document 2).
Japanese Patent Laid-Open No. 2002-210965 JP 2007-137039 A

  Although it is relatively easy to open a stepped through-hole (nozzle opening) in a silicon wafer by dry etching, it takes a long time for the etching process, and it is difficult to improve the working efficiency.

  On the other hand, it is possible to open a nozzle hole with a single hole in a metal plate, but if you try to form a thin metal plate with small holes with a two-step shape at one time, It is difficult to ensure the strength of the punch to be processed, and damage such as bending or bending of the punch frequently occurs, so that it cannot be put to practical use.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide a method for manufacturing a nozzle plate which is difficult to break even when the nozzle opening has a two-stage shape.

In order to achieve the above-described object, a method for manufacturing a nozzle plate according to the present invention is a method in which a first punch is driven halfway in the thickness direction of a metal plate from one surface of the metal plate to the other surface. A first pilot hole forming step of forming a first pilot hole having a bottom on the plate;
By driving a second punch that is thinner than the first punch into the bottom of the first pilot hole from one surface of the metal plate on which the first pilot hole is formed, the bottom of the first pilot hole is lower than the first pilot hole. A second pilot hole forming step of forming a narrow second pilot hole and forming a bulging portion on the other surface;
A penetrating step of grinding the other surface of the metal plate in which the first pilot hole and the second pilot hole are formed to remove the bulging portion and penetrating both pilot holes in series to form a nozzle opening;
It is characterized by including.

The first punch is formed in a columnar shape with an insertion protrusion formed at the distal end portion of the columnar portion with the base end portion fixed to the punch holder and driven into the metal plate,
It is desirable to form the first pilot hole with a flat bottom by driving the insertion protrusion partway into the metal plate.

The insertion protrusion of the second punch has a tapered portion whose diameter is reduced toward the tip, and the tip of the tapered portion is formed of a cylindrical portion having a circular plane;
It is desirable that the second punch hole is formed by driving the second punch into the bottom of the first pilot hole until at least a part of the tapered portion enters.

  Then, it is desirable that a die having a flat surface is disposed below the first punch and the first punch is driven into the metal plate with the metal plate placed on the die.

In this way, a first pilot hole forming step for forming a first pilot hole having a bottom in the metal plate, and the first pilot hole from one surface of the metal plate in which the first pilot hole is formed to the bottom of the first pilot hole. A second pilot hole that forms a second pilot hole that is thinner than the first pilot hole at the bottom of the first pilot hole and forms a bulging portion on the other surface by driving a second punch that is thinner than one punch. If the pilot hole is formed separately in the forming step, the thickness of the portion to be processed by the second punch can be reduced by forming the first pilot hole, thereby forming the thin second pilot hole. Since the load applied to the second punch in can be reduced, damage to the punch can be reduced.
Moreover, even if it is a step-shaped nozzle opening, since it can manufacture by press work, compared with an etching process, a nozzle plate can be manufactured efficiently.

  The liquid jet head mounted with the nozzle plate manufactured by the above-described manufacturing method maintains the high accuracy of the shape without crushing the hole that penetrates the pilot hole, i.e., the nozzle opening in the middle of manufacturing, so that the liquid jet characteristics can be improved. Can be increased.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. Hereinafter, an example in which the present invention is applied to the formation of a nozzle substrate of an ink jet recording head (hereinafter simply referred to as a recording head), which is a kind of liquid ejecting head, will be described.

  FIG. 1 is a cross-sectional view of a main part of a recording head 1 in the present embodiment. The illustrated recording head 1 includes a case 2, a flow path unit 3, an actuator unit 5, and the like as main components. The case 2 is a hollow box-shaped member made of synthetic resin, the flow path unit 3 is joined to the front end surface (lower surface), and the actuator unit 5 is accommodated in the accommodation space 4 formed inside, A circuit board (not shown) for supplying a drive signal from the printer main body side to the actuator unit 5 is attached to the base end surface (upper surface) opposite to the flow path unit 3 side.

  The actuator unit 5 supplies a plurality of piezoelectric vibrators 7 arranged in a comb shape, a fixed plate 8 to which the piezoelectric vibrators 7 are joined, and a drive signal from the circuit board to the piezoelectric vibrators 7. For example, the wiring member 9 is a TCP (tape carrier package). Each piezoelectric vibrator 7 is mounted on the fixed plate 8 in a so-called cantilever state in which the fixed end portion is joined to the fixed plate 8 and the free end portion protrudes outward from the front end surface of the fixed plate 8. Yes. The actuator unit 5 is housed and fixed in the housing space 4 by bonding the back surface of the fixed plate 8 to the inner wall surface of the case that defines the housing space 4.

  The flow path unit 3 is manufactured by joining and integrating a flow path unit constituting member including a vibration plate 11, a flow path forming substrate 12, and a nozzle substrate (nozzle plate) 13 with an adhesive. This is a member that forms a series of ink flow paths (a kind of liquid flow path) from the reservoir 15 (liquid chamber) to the nozzle opening 18 through the ink supply port 16 and the pressure generation chamber 17. The pressure generation chamber 17 is formed as a long and narrow chamber in a direction orthogonal to the direction in which the nozzle openings 18 are arranged (nozzle row direction). The reservoir 15 is a chamber into which ink from an ink supply source such as an ink cartridge or a sub tank is introduced. The ink introduced into the reservoir 15 is distributed and supplied to each pressure generating chamber 17 through the ink supply port 16.

  As shown in FIG. 2, the nozzle plate 13 disposed at the bottom of the flow path unit 3 has a plurality of nozzle openings 18 at a pitch (for example, 180 dpi) corresponding to the dot formation density in the recording medium feeding direction such as recording paper. It is a thin metal plate made in a row. The nozzle plate 13 of the present embodiment is made of, for example, a metal plate material (metal plate 13 ′) such as stainless steel or 42 alloy, and is a row of nozzle openings 18 by pressing using a punch (see FIG. 3 etc.), that is, A plurality of nozzle rows (a kind of nozzle group) are arranged in the scanning direction of the recording head 1. One nozzle row is constituted by, for example, 180 nozzle openings 18. The recording head 1 of the present embodiment is configured to be able to eject a total of eight types of ink, and a total of eight nozzle rows are formed on the nozzle plate 13 corresponding to each ink.

  A flow path forming substrate 12 that is one of the flow path unit constituent members is a flow path base that becomes an ink flow path, specifically, a void that becomes a reservoir 15, a groove that becomes an ink supply port 16, and pressure generation. It is a plate-like member in which an opening serving as the chamber 17 is partitioned. In this embodiment, the flow path forming substrate 12 is produced by subjecting a silicon wafer, which is a crystalline base material, to anisotropic etching.

  The vibration plate 11 disposed on the upper surface of the flow path forming substrate 12 on the side opposite to the nozzle plate 13 is a double-structure composite plate material obtained by laminating an elastic film on a metal support plate such as stainless steel. An island portion 20 for joining the tip of the free end portion of the piezoelectric vibrator 7 is formed at a portion corresponding to the pressure generating chamber 17 of the vibration plate 11. The periphery of the island portion 20 is only an elastic film by removing the support plate in an annular shape by etching or the like. This portion functions as a diaphragm portion, and is configured such that the island portion 20 is displaced while elastically deforming the elastic film as the piezoelectric vibrator 7 expands and contracts. The diaphragm 11 also functions as a compliance unit 21 that seals one open surface of the empty portion of the flow path forming substrate 12 to partition a part of the reservoir 15 and relieve pressure fluctuation in the ink flow path. To do. As for the portion corresponding to the compliance portion 21, the support plate is removed by etching or the like in the same manner as the diaphragm portion to make only the elastic film.

  In the recording head 1 configured as described above, when a drive signal is supplied to the piezoelectric vibrator 7 through the wiring member 9, the piezoelectric vibrator 7 expands and contracts in the longitudinal direction of the element. It moves in a direction close to 17 or a direction away from it. As a result, the volume of the pressure generating chamber 17 changes, and the pressure in the ink in the pressure generating chamber 17 varies. Ink (a kind of liquid) is ejected from the nozzle opening 18 by this pressure fluctuation.

Next, a method of manufacturing the nozzle plate 13 using a press mold will be described with reference to FIG. FIG. 3 is a cross-sectional view illustrating the configuration of the press die.
The press mold includes a die 32 on which a metal plate 31 that is a material of the nozzle plate 13 is placed, a punch holder 33 attached to a lower surface of a ram (not shown) of a press machine, and a spring and an elastomer under the punch holder 33. A pressing plate 35 provided in a state movable up and down with respect to the punch holder 33 via an elastic material 34 such as a first, and a first plate provided toward the lower die 32 with a base end portion fixed to the punch holder 33. The punch 36 and the second punch 50 are roughly configured.

  The metal plate 31 has, for example, a thickness of about 30 to 100 μm and is made of an alloy such as stainless steel or 42 Alloy. Since the metal plate 31 is joined to the flow path forming substrate 12 by heating at 200 ° C. to 300 ° C. using a thermosetting resin or the like, the linear expansion coefficient is preferably close to that of the flow path forming substrate 12. .

  The die 32 is a flat plate made of steel, and can support the metal plate 31 on a flat surface in the first stage processed by the first punch 36 described later, and the second stage processed by the second punch 50. That is, a through-opening 53 having the same size as the prepared hole formed in the first stage is opened at a position corresponding to a position directly below the second punch 50.

  The first punch 36 is formed in a cylindrical shape having an outer diameter of 20 to 30 μm, a cylindrical insertion protrusion 36 ′ is formed at the tip portion, and the tip surface perpendicular to the axial direction is a circular flat surface. It is configured. The base end portion of the first punch 36 is firmly fixed to the punch holder 33, and the intermediate portion in the axial direction is inserted into a through guide hole 43 formed in the pressing plate 35. The guide is lowered while being guided, and the insertion protrusion 36 ′ at the tip is driven in a state orthogonal to the surface of the metal plate 31.

The second punch 50 is a punch thinner than the first punch 36, the base end portion is fixed to the punch holder 33, the insertion protrusion 50 ′ is formed at the tip of the cylindrical shaft portion, and the intermediate portion is the pressing plate 35. And is guided through the through guide hole 51 established in the above. The insertion protrusion 50 'shown in the drawing forms a tapered portion 50a that gradually decreases in diameter toward the tip, and forms a columnar portion 50b that is thinner than the other portions at the tip of the tapered portion 50a. The tip of is a circular plane. The second punch 50 is about 1/3 to 1/4 the thickness of the first punch 36, and the length of the insertion protrusion 50 'is almost the same as the thickness or the insertion depth (first). The thickness is almost the same as the thickness of the bottom of the prepared hole formed by one punch 36).
The distance between the first punch 36 and the second punch 50 is set to the same distance as this pitch because the metal plate is fed by a feeder at a predetermined pitch (for example, the pitch between nozzle rows).

  Next, a case where a prepared hole forming step of forming a prepared hole to be the nozzle opening 18 using the press die having the above-described configuration is described. The die 32 is fixed on a support plate such as a bolster (not shown) of the press machine, the punch holder 33 is fixed to the lower surface of the ram, and the die 32 and the punch holder 33 (first punch 36, second punch 50) are connected. It is assumed that the mold adjustment such as the relative position and the bottom dead center adjustment of the first and second punches 36 and 50 has been completed. The mold shown in the drawing is a progressive mold, and the first pilot hole forming process in the first stage and the second pilot hole forming process in the second stage are performed simultaneously. After forming the pilot hole (first pilot hole) in the first pilot hole forming step, the second pilot hole forming step further processes (forms the second pilot hole) with respect to the pilot hole. .

  First, a stainless steel metal plate 31 is placed on the die 32 at a predetermined position, and the punch holder 33 is lowered with the tips of the first and second punches 36 and 50 facing the metal plate 31. Then, as shown in FIG. 3, the lower surface of the pressing plate 35 comes into contact with the surface of the metal plate 31. Thereafter, when the punch holder 33 is further pushed down while resisting the urging force of the elastic member 34, it is guided to the through guide hole 43 of the pressing plate 35, and as shown in the left half of FIG. The front end of the first punch 36 is pushed in the thickness direction of the metal plate 31 to the middle of the plate thickness, whereby a first pilot hole 40 is formed on the surface side of the metal plate 31 on the flat die 32 (first 1 pilot hole forming step). At this time, the bottom dead center of the first punch 36 is adjusted so that the tip of the first punch 36 is inserted up to 2/3 of the thickness of the metal plate. Accordingly, the first pilot hole 40 formed by driving the first punch 36 has an inner diameter that is the same as the outer diameter of the first punch 36, and the depth is up to about 2/3 of the thickness of the metal plate. Thus, the thickness of the non-penetrating portion 41 that is the bottom of the lower hole is about 1/3 of the plate thickness, which is significantly thinner than the plate thickness of the entire metal plate 31. Therefore, the driving distance of the second punch 50 described later may be short.

  When the first punch 36 descends to the bottom dead center and forms a cylindrical pilot hole (first pilot hole 40) on the surface side of the metal plate 31, the first punch 36 starts to rise. When the punch holder 33 rises with the rise of the ram, the pressing plate 35 starts to rise slightly later than the punch holder 33 due to the restoring force of the elastic material 34, and is separated from the surface 31 a of the metal plate 31. It rises to the dead point. This completes the first pilot hole forming step in the first stage.

  Then, when the first pilot hole forming step is completed, the metal plate 31 is moved by the feeder by a predetermined pitch for the next pilot hole formation (second pilot hole forming step). When this movement (feeding) is completed, the first first holes 40 can be opened at a predetermined pitch at a new position of the metal plate 31 in the first stage by repeating the above-described operation again. In the second stage, the first pilot hole 40 is processed (second pilot hole forming step).

  In the second pilot hole forming step, the first pilot hole 40 formed in the first pilot hole forming step is positioned below the second punch 50 and stopped. When the punch holder 33 is lowered in this state, the first punch 36 and the second punch 50 are lowered after the pressing plate 35 comes into contact with the surface 31 a of the metal plate 31. When the first punch 36 is lowered, the first pilot hole 40 is formed in a new part of the metal plate 31 as described above. On the other hand, when the second punch 50 is lowered, the insertion protrusion 50 ′ formed at the tip of the second punch 50 is pushed into the bottom of the first pilot hole 40 previously formed, and thereby the insertion protrusion of the second punch 50. A second pilot hole 42 having the same size and shape as 50 'is formed. Further, in the present embodiment, the distal end surface of the insertion protrusion 50 ′ of the second punch 50 is pushed to substantially the same depth as or slightly deeper than the back surface (lower surface) 31 b of the metal plate 31. Since 53 is open, the second pilot hole 42 is formed at the bottom of the first pilot hole 40 and, at the same time, the bulging part 52 is formed on the back surface of the metal plate 31.

  Since the thickness of the bottom (non-penetrating portion 41) of the first pilot hole 40 into which the second punch 50 is driven is thinned to about の of the plate thickness of the metal plate material, the load on the second punch 50 is As compared with the case where the prepared hole having the same step shape is formed by pressing the punch once, it is much reduced. Therefore, even if the second punch 50 is thin, damage is reduced and practical durability is obtained.

  In this way, when the second punch 50 is lowered to the bottom dead center to form a thinner second pilot hole 42 at the bottom of the cylindrical first pilot hole 40, the second punch 50 is then raised. When the punch holder 33 rises with the rise of the ram, the pressing plate 35 starts to rise slightly later than the punch holder 33 due to the restoring force of the elastic material 34, and is separated from the surface 31 a of the metal plate 31. It rises to the dead point.

  Then, the metal plate 31 is moved by a feeder by a predetermined pitch to form the next prepared hole. When this movement is completed, the following prepared holes 40 and 42 can be opened in the metal plate 31 at a predetermined pitch by repeating the above-described operation. The holes 40 and 42 can be opened sequentially at a predetermined pitch.

  When the second pilot hole forming step is completed in this manner, the metal plate 31 is removed from the press die and conveyed to a polishing apparatus (not shown) that performs the next penetration step. In this penetrating process, the bulging portion 52 of the second pilot hole 42 remaining in the second pilot hole forming process is polished and removed, thereby penetrating the hole into the nozzle opening 18 and setting the thickness of the metal plate 31 to a predetermined value. Polish to a thickness of. In this way, the nozzle plate 13 in which the nozzle openings 18 are opened is manufactured.

  In each of the above-described embodiments, the larger first pilot hole 40 has a cylindrical shape, and the second pilot hole 42 has a shape in which a truncated cone shape and a cylindrical shape are continuous. However, the present invention is not limited to this. For example, the first pilot hole 40 may have a truncated cone shape, and the cylindrical second pilot hole 42 may be formed at the bottom thereof.

FIG. 3 is a cross-sectional view of a main part for explaining the configuration of a recording head. It is a top view of a nozzle plate. It is principal part sectional drawing explaining the press metal mold | die used by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Recording head, 2 ... Case, 3 ... Flow path unit, 4 ... Accommodating empty part, 5 ... Actuator unit, 7 ... Piezoelectric vibrator, 8 ... Fixed plate, 9 ... Wiring member, 11 ... Vibration plate, 12 ... Flow Path forming substrate, 13 ... nozzle plate, 15 ... reservoir, 16 ... ink supply port, 17 ... pressure generating chamber, 18 ... nozzle opening, 20 ... island part, 21 ... compliance part, 31 ... metal plate, 32 ... die, 33 DESCRIPTION OF SYMBOLS Punch holder, 34 ... Elastic material, 35 ... Pressing board, 36 ... Punch, 36 '... Insertion protrusion, 40 ... First pilot hole, 41 ... Non-penetrating part, 42 ... Second pilot hole, 43 ... Through guide hole 50 ... second punch, 50 '... second punch insertion protrusion, 51 ... through guide hole, 52 ... bulge, 53 ... opening

Claims (5)

A first pilot hole forming step of forming a first pilot hole having a bottom in the metal plate by driving a first punch halfway in the thickness direction of the metal plate from one surface of the metal plate toward the other surface; ,
By driving a second punch that is thinner than the first punch into the bottom of the first pilot hole from one surface of the metal plate on which the first pilot hole is formed, the bottom of the first pilot hole is lower than the first pilot hole. A second pilot hole forming step of forming a narrow second pilot hole and forming a bulging portion on the other surface;
A penetrating step of grinding the other surface of the metal plate in which the first pilot hole and the second pilot hole are formed to remove the bulging portion and penetrating both pilot holes in series to form a nozzle opening;
The manufacturing method of the nozzle plate characterized by including. The first punch is formed at the tip end portion of the columnar portion with the base end portion fixed to the punch holder, and the insertion protrusion that is driven into the metal plate is formed in a columnar shape,
2. The method for manufacturing a nozzle plate according to claim 1, wherein the insertion projection is driven partway into the metal plate to form a first pilot hole with a flat bottom. The insertion protrusion of the second punch has a tapered portion whose diameter is reduced toward the tip, and the tip of the tapered portion is formed of a cylindrical portion having a circular plane;
The method for manufacturing a nozzle plate according to claim 2, wherein the second punch hole is formed by driving the second punch into the bottom of the first pilot hole until at least a part of the tapered portion enters.   4. A die having a flat surface is disposed below the first punch, and the first punch is driven into the metal plate in a state where the metal plate is placed on the die. The manufacturing method of the nozzle plate as described in 2.   A liquid ejecting head, comprising: a nozzle plate manufactured according to claim 1; and a droplet ejected from the through hole serving as a nozzle opening.

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