JP3212058B2 - Mold for forming nozzle plate and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a nozzle plate in which a plurality of ink ejection ports are simultaneously formed by injection molding, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a method of manufacturing a nozzle plate of an ink jet head having a plurality of ink ejection ports by using an injection molding technique is well known. As a method for manufacturing the above-described nozzle plate, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-297765, after injection molding with a polymer resin material, the ink ejection port is subjected to laser processing using an excimer laser device or the like. Methods of forming are known.

However, the excimer laser device is a very expensive device, and the production cost of the nozzle plate has increased accordingly. In addition, since the manufacturing is performed as a separate process from the injection molding process and the orifice portion forming process, the number of processes and manufacturing equipment are increased, the production cost is high, and mass productivity is poor.

[0004] Conventionally, a method of forming a nozzle hole by injection molding has also been attempted. Therefore, a molding die for simultaneously forming a plurality of ink ejection ports at the time of injection molding has been proposed.

[0005] As a structure of a molding die for the nozzle plate, a plurality of separate members corresponding to the ink ejection ports as shown in FIG. Core pin 113 to base core 111
Or a thin plate 123 having portions (projections) corresponding to a plurality of ink ejection ports and a thin plate 133 corresponding to a space between the plurality of ink ejection ports as shown in FIG. A bonding structure is considered.

[0006]

However, the structure of the injection mold having the above-described structure is a complicated structure including a plurality of members, and the production cost of the mold is high. There was a problem that the cost was high.

Further, since these dies are composed of a plurality of members, if the assembling accuracy of the members is not uniform, the accuracy tends to vary among the dies. In particular, in the structure shown in FIG. 8, high bonding accuracy is required between the plates 123 and 133, but the thin film plates 123 and 1 on the order of tens of μm are required.
It was difficult to bond 33, and in reality, there were many bonding failures, and there was a step on each of the plates 123 and 133.
For this reason, there is a high possibility that a step may be formed in a molded product using this mold, and a nozzle plate having an irregular ink ejection port and poor print quality may be produced.

The present invention has been made to solve the above-mentioned problems, and provides a mold for molding a nozzle plate having a low manufacturing cost and high accuracy, thereby providing excellent printing quality and low cost. It is an object to provide an ink jet head.

[0009]

In order to achieve this object, a nozzle plate forming die according to the first aspect of the present invention has a plurality of ink flow paths connected to a tapered portion and a tapered portion.
Multiple nozzles each with an orifice
A mold core for forming an injection molding cavity of the nozzle plate together with a mold plate; and the plurality of orifice portions.
And the arrangement direction of the plurality of crowns
Forward on both sides parallel to and away from its crown
A plate-shaped crest having a side surface that expands toward the mold core.
Thus, the surfaces orthogonal to the side surfaces are substantially spaced apart from each other.
A plurality of crest and parallel arrangement that is integrally formed with the same member.

Further, the method of manufacturing mold of the nozzle plate according to claim 2 of the present invention in order to achieve the above object, the mold core that constitutes the injection molding cavity of nozzle plate with the mold plate Arrangement of the plurality of orifice portions
The side extending parallel to the longitudinal direction and extending in the row direction
A continuous ridge having a shape expanding toward the mold core is integrally formed with the same member, and then the continuous ridge is formed in the longitudinal direction.
A right angle performs grooving, each <br/> portion having a plane substantially parallel spaced from each other is divided into a plurality by the grooving, as crest defining a plurality of nozzles, respectively it Form.

The mold member may be formed with a first blade by grooving at least near the top of the continuous mountain portion to form a convex portion forming the orifice portion. The continuous ridge may be divided by performing grooving with a second blade having a smaller width, and the independent ridge may be formed.

[0012]

According to the nozzle plate forming die according to the first aspect of the present invention, the die core forming the base of the die, and the top defining the plurality of orifice portions.
Part and its multiple parietal parts on both sides parallel to the arrangement direction
In the mold core as it moves away from its tip.
A plate-shaped crest having a side surface that is enlarged
Planes that are perpendicular to and are almost parallel to each other
The plurality of ridges are integrally formed of the same member. During the injection molding of the nozzle plate, a tapered portion and an orifice portion are defined by the peak portion , and a plurality of nozzles are formed.
There Ru is formed in sequence. Since it is composed of one member as described above, bonding failure does not occur as in the case of being composed of another member, the accuracy of the mold can be increased, and the uniformity of the diameter and pitch of the ink ejection ports can be improved. In addition to molding the nozzle plate, it can sufficiently cope with the molding of a nozzle plate having high-density ink ejection ports.

According to the mold manufacturing method of the nozzle plate according to claim 2 of the present invention, the orifice portion of the multiple
A mold that extends long in the arrangement direction and that is parallel to the longitudinal direction
A plurality of ridges are formed by integrally forming a continuous ridge having a shape expanding toward the core with the same member on the mold core, and grooving the continuous ridge. Therefore, a die can be manufactured with high accuracy and at low cost by this simple method, and the manufacturing cost of the nozzle plate can be suppressed.

According to the manufacturing method of the mold of the nozzle plate according to claim 3, by performing the grooving using the two wide blades, easily crest, the orifice portion and the tapered It is formed in a shape corresponding to the part.

[0015]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the ink-jet head 1 is provided with a flat piezoelectric ceramic plate 2 made of polarized piezoelectric / electrostrictive elements, a ceramic cover plate 3, and a plurality of nozzles 64. And a nozzle plate 61.

A groove (not shown) is formed in the piezoelectric ceramic plate 2, and a metal electrode (not shown) is formed on an upper half of a side wall of the groove. The cover plate has an ink inlet 21 and a manifold (not shown). Then, the piezoelectric ceramic plate 2 and the cover plate 3 are adhered with an epoxy-based adhesive.
A plurality of ink flow paths 12 (see FIG. 2) having a predetermined interval in the horizontal direction are formed by covering the upper surface of the groove.

A nozzle plate 61 is adhered to the end faces of the piezoelectric ceramic plate 2 and the cover plate 3 so that the nozzles 64 are connected to the positions of the respective ink flow paths 12 as shown in FIG. You.

FIG. 2 is a sectional view of the ink jet head 1. The nozzles 64 formed on the nozzle plate 61 include a tapered portion 63 and an orifice portion 62. In particular, the diameter and pitch of the orifice portion 62 of each nozzle 64 determine the print quality of the ink jet head.

The nozzle plate 61 is formed by injection molding of polysulfone, which is a resin material, using a mold of this embodiment whose structure is schematically shown in FIG. In FIG. 3, a peak portion 103 corresponds to the tapered portion 63 and the orifice portion 62 of the nozzle plate 61, and is integrally formed with the mold core 110 made of cemented carbide with the same member.

FIG. 4A is a perspective view of the mold core 110.
Shown in A method for manufacturing the mold core 110 will be described. First, as shown in FIG. 4B, a mold core material 10 having a continuous crest 13 having a continuous crest 103 is manufactured by a commonly used cutting, grinding, wire cutting, or the like. Next, the continuous crests 13 are divided using a diamond blade, and each crest 103 is obtained by grooving into an independent shape. At this time, as shown in FIG. 5, first, a shallow groove is formed by a wide diamond blade 52, and then a groove is formed deeply by a narrow diamond blade 53 at a position formed by the wide diamond blade 52. Insert and process. Thereby, a portion corresponding to the tapered portion 63 and the orifice portion 62 is formed. The order of the grooving of the two types of diamond blades having different widths may be reversed.

As described above, the mold core for forming the nozzle 64 can be manufactured more easily than the conventional method of combining separate members such as pins or plates shown in FIG. 7 or FIG. High accuracy and low mold manufacturing cost.

If the cemented carbide is grooved with a diamond blade, the surface roughness of the grooved surface becomes better than that of a general alloy tool steel for a mold. Therefore, it is more preferable because the release resistance at the time of releasing the injection molded product can be reduced without polishing the grooving surface of the fine peak portion 103.

In addition to the above-described method of grooving a plurality of times with diamond blades having different widths, as shown in FIG.
4 may be used to form the ridge 103 corresponding to the tapered portion 63 and the orifice portion 62 at one time.

Next, the mold core 110 made of cemented carbide formed by the above-described method is mounted on the movable mold plate 101 as shown in FIG. The mold plate 101 is clamped. Next, the polysulfone in a molten state passes through the sprue 106 into the mold core 110 on which the crest 103 is formed, the cavity 120 surrounded by the fixed mold plate 104 and the movable mold plate 101, and passes through the gate. 1
00, the nozzle plate 61 is injection molded. Next, after leaving for a predetermined cooling time, the fixed side template 10
4 and the movable mold plate 101 are opened. The nozzle plate 6 is moved by moving the eject pin 105.
1 is taken out of the cavity 120.

In the nozzle plate 61 manufactured by the above method, the nozzles 64 are formed at high density and the orifices 62 of the nozzles 64 are aligned. The ink jet head 1 using the nozzle plate 61 has good print quality. Met.

As described above, the material of the nozzle plate according to the present invention is not only polysulfone, but also liquid crystal polymer, polyacetal, polyphenylsulfone, polyphthalamide, polyphenylene oxide, polyphenylene sulfide, polyetherimide, and polyether sulfone. And a resin material such as polycarbonate.

Further, the nozzle plate 61 can be manufactured by using an injection molding technique of ceramic powder or metal powder. That is, a ceramic powder or a metal powder is mixed and kneaded with a binder such as a resin material, injection-molded into a mold, and an injection-molded body is obtained. Then, the resin material is removed from the injection-molded body by degreasing, and the degreased body is removed. obtain. Further, the degreased body is inserted into a sintering furnace to perform a sintering process. The degreased body shrinks by this sintering process, and is about 10 to 30% smaller than the mold size.
About small. For this reason, the nozzle dimensions and pitch on the mold side need to be larger in consideration of shrinkage than the product.

Also, in this type of ink jet head, high integration of nozzles is desired. However, if the mold members are to be miniaturized as they are and high integration is performed, the flow resistance at the time of injection molding is increased, and Not preferred in terms of sex.
Therefore, if the ceramic or metal injection molding technique is used, the mold size can be set larger than the actual size, so that it is possible to cope with an ink jet head in which nozzles are more highly integrated. As the ceramic powder and the metal powder, for example, alumina, zirconia, silicon nitride, silicon carbide, stainless steel, or the like can be used.

The present invention is not limited to the above-described embodiment, but can be applied to various methods of manufacturing ink jet nozzle plates such as a so-called bubble jet type.

[0031]

As apparent from the above description, according to the nozzle plate forming die of the present invention, a plurality of orifices are provided.
The top of the head defining the fist part, and the plurality of tops
Away from the crown on both sides parallel to the array direction
A plate-like shape having a side surface that expands toward the mold core
The peaks, which are perpendicular to the side surfaces, are spaced apart from each other.
A plurality of ridges disposed substantially parallel to, There are, because they are made form together the same member and the mold core, morphism nozzle plate
At the time of forming, the tapered portion and orifice
The nozzle portion is defined, and a plurality of nozzles are arranged and formed.
In addition, a highly accurate mold can be provided, and the printing quality is excellent, and it can be manufactured at low cost.

Further, according to the manufacturing method of the mold of the nozzle plate of the present invention, the arrangement direction of the plurality of cage office unit
And the side parallel to the longitudinal direction faces the mold core.
With the same material as the mold core,
Integrally forming and grooving the continuous mountain
Since a plurality of peaks are formed, a mold can be manufactured with high accuracy and low cost by a simple method, and the manufacturing cost of the nozzle plate can be suppressed.

Furthermore, by performing the grooving using the two wide blade easily mold member can be formed in a shape corresponding to the orifice portion and the tapered portion.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing the configuration of an ink jet head.

FIG. 2 is a cross-sectional view illustrating an inkjet head.

FIG. 3 is an explanatory view schematically showing a configuration of an injection mold for manufacturing a nozzle plate according to one embodiment of the present invention.

FIG. 4 is an explanatory view showing an injection molding die core of the nozzle plate of the embodiment.

FIG. 5 is an explanatory view showing a method of manufacturing a mold core for injection molding of a nozzle plate of the embodiment.

FIG. 6 is an explanatory view showing a method of manufacturing a mold core for injection molding of a nozzle plate according to another embodiment.

FIG. 7 is a cross-sectional view schematically showing a configuration of a conventional injection mold core for a nozzle plate.

FIG. 8 is a perspective view schematically showing the configuration of an injection molding die core of another conventional nozzle plate.

[Explanation of symbols]

 2 Piezoelectric ceramic plate 3 Cover plate 52 Diamond blade 53 Diamond blade 54 Diamond blade 61 Nozzle plate 62 Orifice part 63 Taper part 64 Nozzle 103 Mountain part 110 Mold core

Claims (3)

(57) [Claims] A plurality of ink flow paths, a tapered portion,
Multiple nozzles each with a continuous orifice section
In a mold for forming a nozzle plate formed on a nozzle plate, a mold core defining an injection molding cavity of the nozzle plate together with a mold plate, a top portion defining the plurality of orifices, and
The parietal on both sides parallel to the arrangement direction of the plural parietal
Side that expands towards the mold core as it moves away from the part
Is a plate-shaped crest having a surface orthogonal to the side surface.
A molding die for a nozzle plate, wherein a plurality of ridges arranged substantially parallel to each other at intervals are integrally formed of the same member. 2. A method according to claim 1, further comprising the steps of:
Multiple nozzles each with a continuous orifice section
A method of manufacturing a mold for molding a nozzle plate formed on a nozzle plate, the method comprising: arranging the plurality of orifices on a mold core that forms an injection molding cavity of the nozzle plate together with the mold plate.
The mold parallel to the longitudinal direction
Integrally formed of the same member of the continuous crest is shaped to expand toward the A, mutually are subsequently divided, performs the longitudinal direction perpendicular to grooving to the continuous ridges, the plurality by the grooving
Each section having substantially parallel surfaces spaced, their respective
A method of manufacturing a molding die for a nozzle plate, wherein the molding is formed as a peak defining a plurality of nozzles . 3. a step of forming a convex portion forming the orifice portion by grooving the continuous peak portion at least near the top of the continuous peak portion with a first blade; by processing grooving width by a narrow second blade from the blade, according to claim 2, wherein the continuous ridges divided and characterized by being formed by forming a separate said dividing ridges Method for manufacturing a mold for forming a nozzle plate.