JPH08104009A - Mold for molding nozzle plate and production thereof - Google Patents

Abstract

PURPOSE: To obtain a mold capable of producing a nozzle plate excellent in the printing quality and bring inexpensive. CONSTITUTION: A mold for molding a nozzle plate forming a plurality of ink jet orifices simultaneously with injection molding is produced by integrally forming a continuous ridge part to the mold core 110 composed of a hard alloy and forming the base part of an injection mold from the same hard alloy and forming respective ridge parts 103 corresponding to taper parts 63 and orifice parts by groove processing using wide and narrow diamond blades 52, 53.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a method of forming 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 nozzle plate as described above, for example, as disclosed in Japanese Patent Laid-Open No. 3-297651, after injection molding with a polymer resin material, the ink ejection port is laser-processed by 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 is correspondingly high. Moreover, since the manufacturing process is performed separately 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 the mass productivity is poor.

Further, conventionally, a method of forming a nozzle hole by an injection molding method has also been tried. Therefore, a molding die has been proposed for simultaneously forming a plurality of ink ejection ports during injection molding.

As the structure of the molding die for the nozzle plate, a plurality of separate bodies corresponding to the ink ejection ports as shown in FIG. 7 are provided so as to satisfy the fine accuracy of the diameter of the ink ejection port and its pitch. The core pin 113 of the 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 plurality of ink ejection ports as shown in FIG. A structure for laminating is considered.

[0006]

However, the structure of the injection-molding die having the above-mentioned structure is a complicated one composed of a plurality of members, the manufacturing cost of the die is high, and as a result, the nozzle plate is produced. There was a problem of high cost.

Further, since these molds are composed of a plurality of members, if the assembling accuracy of the members is not uniform, the accuracy tends to vary from mold to mold. In particular, the structure shown in FIG. 8 requires high bonding accuracy between the plates 123 and 133, but the thin film plates 123 and 1 of the order of tens of μm are used.
It was difficult to bond 33, and in reality, there were many bonding failures, and a step was formed between the plates 123 and 133.
Therefore, there is a high possibility that a step will be formed in a molded product by this mold, and a nozzle plate having uneven ink ejection ports and poor printing quality will be produced.

The present invention has been made in order to solve the above-mentioned problems, and provides a mold for molding a nozzle plate with low manufacturing cost and high accuracy, and by extension, excellent printing quality and low cost. It is an object to provide an inkjet head.

[0009]

In order to achieve this object, a mold for molding a nozzle plate according to a first aspect of the present invention is such that a nozzle plate used for an ink jet head is injection-molded, and at the time of the injection molding. A plurality of ink ejection ports are formed, and further, a mold core forming a base portion of the injection molding mold and at least a mold member defining the ink ejection port are integrally formed of the same member. There is.

The mold member has a peak shape that defines a taper portion of the ink ejection port, and a convex portion that defines an orifice section of the ink ejection port is provided on the top of the peak portion. May be.

At least the mold core and the mold member are preferably made of cemented carbide.

Further, in order to achieve the above object, in the method for manufacturing a die for molding a nozzle plate according to a fourth aspect of the present invention, a continuous core portion is formed in the same member on a die core forming a base portion of the die. Then, the continuous crest portion is subjected to grooving, and each of the plurality of parts divided by the grooving is formed as a mold member that defines at least the ink ejection port.

It is to be noted that the mold member has a step of forming a convex portion corresponding to an orifice portion of the ink ejection port by grooving at least the vicinity of the top portion of the continuous mountain portion with the first blade, It may be formed by a step of dividing the continuous mountain portion by forming a groove by a second blade having a width narrower than that of the first blade and forming the independent divided mountain portion.

The mold member is formed in one step by an integrated blade whose tip width changes stepwise,
A convex portion corresponding to the orifice portion of the ink ejection port and the independent divided mountain portion may be simultaneously formed.

The grooving may be performed by using a diamond blade.

[0016]

According to the mold for molding a nozzle plate according to claim 1 of the present invention having the above-mentioned structure, the mold core forming the base of the mold and the mold member are integrally formed of the same member. ing. Then, at the time of injection molding of the nozzle plate, at least the ink ejection port is defined by the mold member. Since it is composed of one member in this way, it does not cause a bonding failure as in the case of being composed of another member, the accuracy of the mold can be improved, and the diameter and pitch of the ink ejection ports are well aligned. In addition to molding the nozzle plate, it is also possible to sufficiently mold a nozzle plate having a high-density ink ejection port.

Further, in the mold for molding the nozzle plate according to the second aspect, at the time of molding, the mold member defines the taper portion of the ink ejecting portion by the shape of the peak portion, and the convex portion at the top of the head member. The orifice section of the ink ejecting section is defined.

Further, in the mold for molding the nozzle plate according to the third aspect, since at least the mold core and the mold member are made of cemented carbide, the moldability of the injection-molded nozzle plate from the mold is high. Get better

According to the method for manufacturing the nozzle plate molding die according to the fourth aspect of the present invention, the continuous peak portion is integrally formed with the mold core by the same member, and the continuous peak portion is grooved. By doing so, a mold member is formed. Therefore, the mold 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 method for manufacturing a die for molding a nozzle plate according to the fifth aspect of the present invention, the die member is easily grooved by using the blades having two kinds of widths, and the orifice of the ink ejection port is easily formed. It is formed in a shape corresponding to the tapered portion and the tapered portion.

According to the method for manufacturing a die for molding a nozzle plate according to a sixth aspect of the present invention, grooving is performed using a blade whose tip width is changed stepwise, so that the die member can be formed into an ink at a time. It is formed in a shape corresponding to the orifice portion and the tapered portion of the injection port.

According to the method for manufacturing a nozzle plate molding die according to the seventh aspect, since the grooving is performed by grooving with a diamond blade, the processed surface has a good surface roughness and is injection molded. The release resistance when releasing the nozzle plate is reduced.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 composed of polarized piezoelectric / electrostrictive elements, a ceramic cover plate 3, and a plurality of nozzles 64. It is composed of a nozzle plate 61.

A groove (not shown) is formed on the piezoelectric ceramic plate 2, and a metal electrode (not shown) is formed on the upper half of the side wall of the groove. Further, an ink inlet 21 and a manifold (not shown) are formed on the cover plate. Then, the piezoelectric ceramic plate 2 and the cover plate 3 are bonded to each other with an epoxy adhesive, whereby the inkjet head 1 is
The upper surfaces of the grooves are covered to form a plurality of ink channels 12 (see FIG. 2) laterally spaced from each other by a predetermined distance.

As shown in FIG. 2, the nozzle plate 61 is bonded 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 ink flow paths 12. It

FIG. 2 shows a sectional view of the ink jet head 1. The nozzles 64 formed on the nozzle plate 61 are composed of a taper portion 63 and an orifice portion 62, and in particular, the diameter and pitch of the orifice portion 62 of each nozzle 64 determine the print quality of the inkjet head.

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

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

As described above, the mold core of the portion 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. The accuracy is high and the die manufacturing cost can be kept low.

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

Further, in addition to the above method of grooving a plurality of times with diamond blades having different widths, as shown in FIG.
4, the mountain portion 103 corresponding to the tapered portion 63 and the orifice portion 62 may be formed at once.

Next, the die core 110 made of cemented carbide formed by the above method is mounted on the movable side mold plate 101 side as shown in FIG. 3, and the fixed side mold plate 104 and the movable side mold plate 104 are attached. The template 101 is clamped. Next, the polysulfone in a molten state passes through the sprue 106 into the cavity 120 surrounded by the mold core 110 on which the mountain portion 103 is formed, the fixed-side mold plate 104, and the movable-side mold plate 101, and then gates. 1
00, and the nozzle plate 61 is injection molded. Next, after standing for a predetermined cooling time, the fixed-side template 10
4 and the movable side mold plate 101 are opened. Then, by moving the eject pin 105, the nozzle plate 6
1 is taken out from the cavity 120.

In the nozzle plate 61 manufactured by the above method, the nozzles 64 are formed in high density and the orifice portions 62 of each nozzle 64 are aligned, and the ink jet head 1 using the nozzle plate 61 has good printing quality. Met.

As the material of the nozzle plate according to the present invention as described above, in addition to polysulfone, liquid crystal polymer, polyacetal, polyphenylsulfone, polyphthalamide, polyphenylene oxide, polyphenylene sulfide, polyether imide, polyether sulfone A resin material such as polycarbonate can be used.

The nozzle plate 61 can also be manufactured by using an injection molding technique of ceramic powder or metal powder. That is, ceramic powder or metal powder is mixed and kneaded with a binder such as a resin material, injection-molded in a mold to obtain an injection-molded body, and then degreasing treatment is performed to remove the resin material from the injection-molded body and remove the degreased body. obtain. Further, the degreased body is inserted into a sintering furnace to perform a sintering process. The degreasing body shrinks due to this sintering process, and is about 10 to 30% of the size of the mold.
It gets smaller. For this reason, it is necessary to make the nozzle size and pitch on the die side larger in consideration of shrinkage than the product.

Further, in this type of ink jet head, it is desired that the nozzles be highly integrated. However, if the mold members are made finer and the density is increased, the flow resistance at the time of injection molding becomes large and the injection molding becomes difficult. It is not preferable in terms of sex.
Therefore, if the ceramics or metal injection molding technique is used, the mold size can be set larger than the actual size, so that it is possible to correspond to an inkjet head in which nozzles are 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-mentioned embodiment, but can be applied to various methods of manufacturing nozzle plates for ink jet such as so-called bubble jet type.

[0039]

As is apparent from the above description, according to the mold for molding the nozzle plate of the present invention, the mold member is integrally formed with the same member as the mold core. The mold can be provided, and the printing quality is excellent, and it can be manufactured at low cost.

Further, if at least the mold core and the mold member of the injection molding die are made of cemented carbide, the mold release resistance at the time of injection molding is small and a nozzle plate having a good shape can be obtained. Excellent print quality.

As is clear from the above description, according to the method for manufacturing the nozzle plate molding die of the present invention, the die can be manufactured with high precision and at a low cost by a simple method. The manufacturing cost can be reduced.

Further, by performing a grooving process using blades of two kinds of width, the mold member can be easily formed into a shape corresponding to the orifice portion and the taper portion of the ink ejection port.

If grooving is performed using a blade whose tip width changes stepwise, the mold member can be formed at a time into a shape corresponding to the orifice portion and the taper portion of the ink ejection port. .

If grooving is performed by grooving with a diamond blade, the surface roughness of the machined surface becomes good, and the mold release resistance at the time of mold release of the injection molded nozzle plate can be reduced. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a schematic configuration of an inkjet head.

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

FIG. 3 is an explanatory view showing the outline of the configuration of an injection molding die for manufacturing a nozzle plate which is an embodiment of the present invention.

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

FIG. 5 is an explanatory view showing a method of manufacturing the injection molding die core of the 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 of another embodiment.

FIG. 7 is a cross-sectional view showing an outline of the configuration of a mold core for injection molding of a nozzle plate of a conventional example.

FIG. 8 is a perspective view showing the outline of 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 Tapered part 64 Nozzle 103 Mountain part 110 Mold core

Claims (7)

[Claims] 1. A mold for manufacturing a nozzle plate in which a nozzle plate used for an inkjet head is injection-molded and a plurality of ink ejection ports are formed at the time of the injection molding. A metal forming a base of the injection-molding mold. A mold for molding a nozzle plate, wherein a mold core and at least a mold member that defines the ink ejection port are integrally formed of the same member. 2. The mold member has a ridge shape that defines a taper portion of the ink ejection port, and a convex portion that defines an orifice portion of the ink ejection port is provided at the top of the ridge portion shape. A mold for molding a nozzle plate according to claim 1, wherein: 3. The mold for molding a nozzle plate according to claim 1, wherein at least the mold core and the mold member are made of cemented carbide. 4. A continuous core is integrally formed on the mold core forming the base of the mold with the same member, and then the continuous peak is grooved and divided into a plurality of grooves by the grooving. Each of the formed parts is formed as a mold member that defines at least the ink ejection port, and a method of manufacturing a mold for molding a nozzle plate. 5. A step of forming a convex portion corresponding to an orifice portion of the ink ejection port, wherein the die member is grooved at least near a top portion of the continuous mountain portion by a first blade, A second blade having a width narrower than that of the first blade is used for grooving to divide the continuous mountain portion to form the independent divided mountain portion. Item 5. A method for manufacturing a nozzle plate molding die according to Item 4. 6. The mold member is formed by an integral blade whose tip width is changed stepwise, and the divided mountain which is independent of a convex portion corresponding to an orifice portion of the ink ejection port in one step. 5. The method for manufacturing a nozzle plate molding die according to claim 4, wherein the portion and the portion are formed at the same time. 7. The grooving process is performed by grooving using a diamond blade.
A method for manufacturing a mold for molding a nozzle plate according to item 1.