JPH1158453A - Injection molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding die for preventing the deformation of a thin wall section and molding stably a molded product of high quality without increasing the cost of a mold. SOLUTION: An injection molding die is used for injection molding a top plate member for a liquid jet recording head, and provided with a molding block 20 for forming a thin wall section of the top plate member used combinedly as an ejection member for ejecting the top plate member 16 from a mold 26 at the time of releasing the top plate member 16 from the mold 26. The surface roughness of a molding face for molding the thin wall section of the molding block is set at the roughness of 3-4μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die for injection molding a top plate for a liquid jet recording head.

[0002]

2. Description of the Related Art Conventionally, a liquid jet head for performing recording by discharging a liquid is formed of a single resin having excellent mechanical strength, dimensional stability and ink resistance. For example,
Polyurethane resins, polyamide resins, melamine resins, liquid crystal polymers and the like are desirable, and resins such as polysulfone and polyethersulfone are particularly desirable from the viewpoint of injection moldability and ink resistance.

In recent years, in an ink jet head capable of obtaining a high quality image stably at a high speed, there is a tendency that the arrangement density of nozzles is further increased and the head size is increased.

In order to reduce costs, a chamber for storing ink, a nozzle (groove) for discharging ink, and an orifice plate having a hole for discharging ink are integrated.

In addition, the orifice plate has a small hole diameter for discharging ink.
The thickness of the portion where this hole is formed also needs to be the same thickness as the hole diameter, and the minimum thickness portion is extremely thin with a thickness of 40 to 50 μm.

[0006] When releasing the molded body of the top plate part having such an extremely thin part from the mold, it is necessary to take measures to prevent the deformation of the orifice plate part.
A method of embedding a two-stage ejection mechanism in a mold or programming an ejection operation procedure on the molding machine side to perform a complicated ejection operation has been adopted.

[0007]

However, in the former method among the above-mentioned conventional methods, the number of parts of the mold increases and the number of mechanical parts increases because the two-stage protrusion mechanism is incorporated in the mold. As a result, not only does the frequency of occurrence of troubles increase, but also the mold processing cost increases. Further, when the protruding operation procedure on the molding machine side is programmed to cope with the problem, since the molding machine is provided with a program, the molding machine is limited, which hinders the running of the molding machine during mass production molding.

Further, as described above, in recent years, it has become necessary to further increase the arrangement density of nozzles, and it is necessary to form a plurality of high-precision groove shapes in the top plate member. 2. Description of the Related Art A method has been adopted in which a top plate member is formed by injection molding a resin using a plurality of molding pieces having a highly accurate groove shape.

As a method of manufacturing a molding piece having a plurality of high-precision grooves, copper, aluminum, iron, or an alloy thereof is used as a base material, and the surface thereof is KN-plated and then diamond-coated. A method of performing thickness adjustment processing and shape processing with a cutting tool and, if necessary, grinding is performed.

In order to surely transfer the groove shape of a molding piece to a molded product, a method such as a high mold temperature molding method or a high-speed injection molding method is employed. Alternatively, there is a method in which a plurality of groove shapes are formed and then processed by a laser processing machine using an excimer laser.

However, the above-mentioned conventional method has the following problems. (1) In the high mold temperature molding method in which the temperature of the mold is raised to near the thermal deformation temperature of the resin to be used and the resin is filled up to the end of the molding piece in a state where the viscosity of the molten resin is low, the mold temperature is increased before the molded product is taken out Needs to be lowered once, and after being taken out, it needs to be raised to near the heat deformation temperature again, which significantly extends the molding cycle and increases the cost of the molded product. (2) In the high-speed injection molding method for filling the molten resin while keeping the viscosity low, an impact force is applied when the resin is injected, particularly immediately below the spool, and the mold is bent and a paris is formed on the radial parting surface. Occur. In order to prevent this paring, the thickness of the mold is increased to improve the mold strength, the locking is enhanced in a mold with a slide mechanism, or the clearance for gas escape is removed. It is necessary to take measures, which increases the manufacturing cost of the mold.

Conventionally, there are a plurality of dimensions which are used as a product shape, and these dimensions are formed by a plurality of pieces, and when this dimensional tolerance is extremely tight, for example, FIG.
In the case where the tolerance of the dimension indicated by f is about ± 2 μ, the following method has been adopted. (1) In the first conventional example shown in FIG. 17, the dimension indicated by h is processed with high precision and fixed with screws. (2) In the second and third conventional examples shown in FIGS. 18 and 19, the dimension indicated by h is processed with high accuracy, and the processing is performed to match the thickness t of the collar of the piece with the actual one.

In any case, after assembling the mold, preforming is performed, the dimensions of the molded article are measured, and if the required accuracy is not satisfied, the mold is removed from the molding machine, modified, and assembled again. The confirmation molding was being performed.

However, in this conventional example, if the dimension is defective during the preforming, the mold is lowered and disassembled, the mold piece is processed and assembled by the correction amount, and the confirmation molding is performed, so that the required precision is obtained. However, there is a problem that it takes a lot of time and increases the cost of the product.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a high-quality molding that can prevent deformation of a thin portion without increasing the cost of a mold. An object of the present invention is to provide an injection mold capable of stably molding a product.

Another object of the present invention is to prevent the occurrence of burrs without increasing the cost of a molded article or a mold, and to stably mold a high-quality molded article. An object of the present invention is to provide a mold for injection molding.

Still another object of the present invention is to provide a mold for injection molding which can easily correct the mold.

[0018]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, an injection mold according to the present invention is an injection mold for injection molding a top plate member for a liquid jet recording head, wherein a thin portion of the top plate member is formed. A molding piece to be formed, characterized by comprising a molding piece which also serves as a projecting member for projecting the top plate member from the mold when the top plate member is released from the mold.

Further, in the injection molding die according to the present invention, the surface roughness of a molding surface for molding the thin portion of the molding piece is set to a predetermined roughness.

Further, in the injection molding die according to the present invention, the surface having the predetermined roughness is formed by performing a polishing process in a direction orthogonal to a direction in which the top plate member protrudes. It is characterized by.

Further, in the injection mold according to the present invention, the predetermined roughness is a surface roughness of 3 to 4 μm.

Further, in the injection molding die according to the present invention, the molding piece has a precise portion, and the precise portion is a plurality of grooves.

Further, the injection molding die according to the present invention comprises:
An injection molding die for injection molding a top plate member for a liquid jet recording head, a molding piece for molding a plurality of precise grooves in the top plate member, wherein the plurality of grooves are formed. The present invention is characterized in that a molding piece having a minute chamfer at the bottom of a groove for molding is provided.

In the injection molding die according to the present invention, the width of the bottom of the groove-shaped portion of the molding piece is 4 μm to 4 μm.
It is characterized in that it is 8 μm.

Further, in the injection molding die according to the present invention, the width of the minute chamfered portion is 1.5 μm to 2.5 μm.
μm.

Further, the injection mold according to the present invention comprises:
An injection molding die for injection molding a top plate member for a liquid jet recording head, comprising: a molding piece for forming a plurality of precise grooves in the top plate member; And adjusting means for adjusting.

In the injection molding die according to the present invention, the adjusting means includes a support member for supporting the molding piece, and a wedge-shaped member disposed between the support member and the main body of the die. And a moving mechanism for minutely moving the wedge-shaped member.

Further, in the injection mold according to the present invention, the moving mechanism comprises a micrometer.

[0029]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a sectional view of a main part around a cavity of an injection molding die 10 according to a first embodiment.

Through the runner 12 and the gate 14,
The molten resin is injected into the cavity 16 formed by the fixed molding piece 24, the movable molding piece 26, and the slide molding piece 28, the resin is awaited for curing, the mold is opened from the separation surface PL, and the protrusion members 18, 20 are formed. The molded product is taken out at. The protruding member 20 also serves as a forming piece for forming an orifice plate of the top plate member 100 described later.

Next, FIG. 2 is a diagram showing the shape of a top plate member 100 for a liquid jet recording head.

The top plate member 100 includes an ink liquid chamber 104 for storing ink and a plurality of grooves 102 forming an ink flow path.
And an orifice plate 103 having an ink discharge hole 106 for discharging ink.

The ink discharge holes 106 are formed by forming a hole in the orifice plate 103 using a laser drilling device using an excimer laser or the like after forming the top plate member 100.

In FIG. 2, the corners where many grooves 102 and the orifice plate 103 are in contact with each other are to avoid interference with the corners of the heater board when a rectangular flat heater board is combined. , Chamfer 3
Accuracy of μm or less is required.

When bonding the heater board and the top plate member, a clearance of 5 μm is provided between the heater board and the many grooves 102 and the frame (liquid chamber frame) 105 of the ink liquid chamber 104. Sealing and bonding are performed using the capillary phenomenon.

By combining with a top plate member 100 a heater board on which a large number of ink heaters are arranged corresponding to the positions of a large number of grooves 102 constituting the ink flow path, it functions as an ink jet head.

FIG. 3 is an enlarged perspective view of the forming piece 20 which forms the lower portion (thin-walled portion) of the orifice plate 103 and also has a function of projecting the top plate member 100 as a formed body.

The molding piece 20 is provided with the ink ejection hole 1 shown in FIG.
The lower part of the orifice plate 103 on which the reference numeral 06 is formed has a function of projecting the molded top plate member 100 from the movable-side molding piece 26.

The molding surface 201 shown in FIG. 3 is a portion for molding the lower part of the orifice plate 103.

FIG. 4 is a cross-sectional view showing a state where the top plate member 100 is protruded by the molding piece 20.

The orifice plate 103 has a thickness of 40 μm at the thinnest portion, and has a thickness of 15 μm even at the thickest portion.
It is very thin, 0 μm.

A molding surface 201 for molding the lower portion of the orifice plate 103 is subjected to a migrating process with a surface roughness of 3 μm to 4 μm in a direction perpendicular to the direction in which the molded product protrudes.

When the molding direction of the molding surface 201 is set to be parallel to the protruding direction, the molten resin and the molding piece 20
Sticks, and when protruding, the orifice plate 103
Is deformed. Further, when the surface roughness becomes 3 μm or less, the molten resin and the molding piece 20 adhere more strongly. When the surface roughness is 5 μm or more, the sticking phenomenon is eliminated, but the amount of undercut in the releasing direction increases or decreases, which has an adverse effect.

In the case where the migrating direction is set to be parallel to the protruding direction and the surface roughness is set to 5 μm or more, the sticking phenomenon is slightly eliminated but cannot be completely eliminated.

Further, it is more effective when the length of the orifice plate 103 in the protruding direction is 2 mm or more.

As described above, according to the present embodiment, the top plate member 100 can be released from the mold without deforming the orifice plate 103 which is a thin portion.

(Second Embodiment) FIG. 5 is a sectional view of a main part around a cavity of an injection molding die 30 according to a second embodiment.

Through the runner 32 and the gate 34,
The molten resin is injected into the cavity 36 formed by the fixed molding piece 44, the movable molding piece 46, and the slide molding piece 48, the resin is awaited for curing, the mold is opened from the separation surface PL, and the projecting members 38, 40 are formed. The molded product is taken out at.

The molded article formed in the second embodiment is exactly the same as the top plate member 100 for the liquid jet recording head shown in FIG. 2, and a description thereof will be omitted.

FIG. 6 is an enlarged perspective view of a large number of grooves 102 in FIG.

In order to improve the quality of the ink jet head, the groove shape required to increase the arrangement density of the large number of grooves 102 constituting the ink flow path is, for example, a flow path wall having a thickness of 4 μm at the tip. Yes, and the groove pitch is 4
0.5 μm. In addition, a 1.5 μm
A chamfered shape part of m to 2.5 μm is formed. In order to form this chamfered portion, the bottom of the groove 46a (see FIG. 5) of the movable-side forming piece 46 is set to 1.5 μm to 2.5 μm.
A chamfer of 5 μm is formed.

FIG. 7 shows a number of grooves 1 without chamfered portions.
It is an enlarged perspective view of 02 '.

According to the study of the present inventors, for example,
When injection molding is performed using a polysulfone resin, the shape of the multiple grooves 102 shown in FIG. 6 and the multiple grooves 10 shown in FIG.
In the shape 2 ′, when molding is performed at the same injection pressure, the same injection speed, and the same mold temperature, the shape of the many groove portions 102 in FIG. While the shape transfer can be accurately performed up to the tip of the groove, the shape of the many groove portions 102 'in FIG. Was not accurately transferred, resulting in an irregular shape.

As described above, by forming a fine chamfered portion at the bottom of the groove on the mold side such that a chamfered portion is formed at the tip of the fine grooved portion of the molded product as in the present embodiment, Even if the thickness of the partition wall of the groove is reduced, the tip of the formed groove does not have an irregular shape, and a high quality molded product can be obtained.

(Third Embodiment) FIG. 8 is a view showing an injection mold 60 of a third embodiment cut into four parts. The center spool 62 is provided so as to be continuous with runners 64 separated in four directions for a multi-cavity mold configuration, and shows a state of a cavity 66 communicating with one of the runners 64. Is shown. Since the molded product formed by the mold 60 is substantially the same as the top plate member 100 for the liquid jet recording head shown in FIG. 2, the description is omitted.

FIG. 9 is a detailed sectional view of the periphery of the cavity 66 of FIG. 10 is an enlarged view of a portion A in FIG. 9, and FIG. 11 is an enlarged perspective view of the molding piece 73.

The injection mold shown in FIG.
The molten resin is injected into the cavity 66 through the cavity 2, the resin is awaited, the mold is opened from the separation plane PL, and the molded product is taken out. The molding piece 73 has a groove 73a for forming a plurality of fine grooves, as can be seen from FIG. 2 showing the shape of the molded product. Extremely high precision is required for the height of the groove portion of the molded product, and the molded product must be molded within a tolerance of about ± 2 μm. The injection molding die 60 of the present embodiment has a mechanism for correcting the height of the molding piece 73 in order to satisfy this accuracy.

The method of correcting a mold according to the present embodiment will be described below.

First, when the quality of the molded product after molding is determined to be defective, specifically, when the dimension f in FIG. 10 deviates to the plus side from the tolerance, the molding piece 73 is formed in the following procedure.
Modify the height of.

First, the molding is interrupted and the mold is opened. Next, the screw 82 is loosened, the wedge piece 76 is lowered, and the piece 74 is moved to the right. Next, the screw 81 is loosened, and the movement amount of the wedge member 71 is calculated from the correction amount and the angle θ in FIG.
7 in the forward direction by this value. Wedge member 71
, A projection member 71 a is attached by a screw, and the tip 77 a of the micrometer 77 is attached to the projection member 7.
Press the tip of 1a. With this operation, the forming piece 73 engaged via the inclined piece 72 moves downward. Next, screw 8
By tightening 1 and further tightening the screw 82, the wedge piece 76 is raised, and the piece 74 is shifted to the left side to clamp the forming piece 73.

When the dimension f in FIG. 10 deviates from the tolerance on the minus side, the height of the molding piece 73 is corrected in the following procedure.

First, the molding is interrupted and the mold is opened. Next, the screw 82 is loosened, the wedge piece 76 is lowered, and the piece 74 is moved to the right. Next, the wedge member 71 is determined from the correction amount and the angle of θ in FIG.
Is calculated, and the micrometer 77 is rotated in the backward direction by this value. The upper end 73a of the molded piece 73 is supported by the inclined piece 72.
, The molding piece 73 is moved upward by the above operation. Next, tighten the screw 81, and further tighten the screw 82, the wedge piece 76 rises,
The forming piece 73 is clamped as the piece 74 moves to the left.

According to this series of operations, the correction can be completed during the molding operation, and the molding can be started immediately after closing the mold. FIG. 12 shows a flowchart of a mold correcting operation according to the related art and the present embodiment.

In the above description, the screw 81 is loosened after the piece 74 is moved to the right, but this procedure may be reversed.

Next, FIG. 13 to FIG. 16 are views showing modified examples of the third embodiment.

As shown in FIG. 13, the angle between the movable direction of the wedge member 71 and the movable direction of the inclined piece 72 may be an angle other than 90 °.

Further, a structure in which the direction of the inclination angle θ is changed as shown in FIG.

Further, as shown in FIGS. 15 and 16, the method of engagement between the molding piece 73 and the inclined piece 72 may be changed.

As described above, according to the present embodiment, the mold can be easily corrected.

The present invention can be applied to a modification or a modification of the above embodiment without departing from the gist of the invention.

[0072]

As described above, according to the present invention,
The top plate member for the liquid jet recording head is prevented from being deformed, especially at a thin portion, and without having a complicated structure of the mold.
Furthermore, it is possible to supply low-priced and stable quality molded products without adding special specifications to the injection molding machine.

Further, a head having a high density of nozzles can be supplied with stable quality without generating burrs on the top molded product for the liquid jet recording head.

Further, since high-speed injection molding and high mold temperature molding are not used, the durability of the molding cavity can be improved.

Further, since the mold can be corrected in a series of molding operations without lowering and disassembling the mold, the repair cost can be reduced.

In addition, since the work of correcting the mold is not complicated and requires skill, it can be corrected even by a molding operator.

In addition, it is not necessary to correct the mold, so that the cost of the correction can be reduced.

[0078]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part around a cavity of an injection mold according to a first embodiment.

FIG. 2 is a diagram illustrating a shape of a top plate member for a liquid jet recording head.

FIG. 3 is an enlarged perspective view of a forming piece that forms a lower portion (a thin-walled portion) of an orifice plate and also has a function of protruding a top plate member as a formed body.

FIG. 4 is a cross-sectional view showing a state in which a top plate member is protruded by a molding piece.

FIG. 5 is a cross-sectional view of a main part around a cavity of an injection mold according to a second embodiment.

FIG. 6 is an enlarged perspective view of a number of grooves in FIG.

FIG. 7 is an enlarged perspective view of a number of grooves without a chamfered shape.

FIG. 8 is a view showing the injection molding die of the third embodiment cut into four parts.

FIG. 9 is a detailed cross-sectional view around the cavity of FIG. 8;

FIG. 10 is an enlarged view of a portion A in FIG. 9;

FIG. 11 is an enlarged perspective view of a molding piece.

FIG. 12 is a flowchart of a mold correcting operation according to the conventional and the third embodiment.

FIG. 13 is a view showing a modification of the third embodiment.

FIG. 14 is a diagram showing a modification of the third embodiment.

FIG. 15 is a view showing a modification of the third embodiment.

FIG. 16 is a diagram showing a modification of the third embodiment.

FIG. 17 is a diagram showing a first conventional example.

FIG. 18 is a diagram showing a second conventional example.

FIG. 19 is a diagram showing a third conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Injection molding die 12 Runner 14 Gate 16 Cavity 18,20 Projection member 22 Projection pin 24 Fixed molding piece 26 Movable molding piece 28 Slide molding piece 102 Groove portion 103 Orifice plate 104 Ink liquid chamber 105 Liquid chamber frame 201 Molding surface

Claims (11)

[Claims] 1. An injection molding die for injection molding a top plate member for a liquid jet recording head, wherein the molding plate forms a thin portion of the top plate member. An injection molding die, comprising: a molding piece which also functions as a projecting member for projecting the top plate member from the mold when the mold is released from the mold. 2. The injection mold according to claim 1, wherein a surface roughness of a molding surface for molding the thin portion of the molding piece is set to a predetermined roughness. 3. The injection according to claim 2, wherein the surface having the predetermined roughness is formed by performing a polishing process in a direction orthogonal to a direction in which the top plate member protrudes. Mold for molding. 4. The predetermined roughness is a surface roughness of 3 to 4 μm.
The injection mold according to claim 2, wherein the roughness is m. 5. The injection mold according to claim 1, wherein the molding piece has a precision part, and the precision part is a plurality of grooves. 6. An injection molding die for injection-molding a top plate member for a liquid jet recording head, comprising: a molding piece for forming a plurality of precise grooves in the top plate member; An injection molding die comprising a molding piece having a minute chamfer at the bottom of a groove for molding the plurality of grooves. 7. The width of the bottom of the groove portion of the molding piece is 4
The injection mold according to claim 6, wherein the diameter is from 8 m to 8 m. 8. The width of the minute chamfer is 1.5 μm.
The injection mold according to claim 6, wherein the thickness is from 2.5 to 2.5 m. 9. An injection molding die for injection-molding a top plate member for a liquid jet recording head, comprising: a molding piece for forming a plurality of precise grooves in the top plate member; An injection molding die comprising: an adjusting means for finely adjusting a position of a piece. 10. The adjusting means includes: a support member for supporting the molding piece; a wedge-shaped member disposed between the support member and the main body of the mold; and a movement for minutely moving the wedge-shaped member. The mold for injection molding according to claim 9, further comprising a mechanism. 11. The injection mold according to claim 10, wherein the moving mechanism is constituted by a micrometer.