JP2003071876A - Mounting structure of stamper for mold for injection molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold structure capable of rationally and economically replacing a stamper by preventing the stamper from being deviated at a mounting position due to an expansion or a filling pressure of the stamper caused by a heat of a molten resin without necessity of replacing the mold. SOLUTION: A mounting structure of the stampers for the mold for injection molding comprises plurality of stationary stamper retaining members 21 fixed to a lower part and a left side of a fixed mold 10, and the stampers 17 mounted thereon. The mounting structure further comprises a handle 46 for converting a rotary force transmitted via a gear mechanism of a driver 30 attached in a stamper replacing unit 20 into a linearly reciprocating force via a rack gear 26 of slide bars 24, 27 by rotating, and a movable stamper retaining member 23 pressed by an energizing force of a spring 19 to a movable state in inner and outer circumferential directions of the mold 10 by utilizing an oblique surface of the cutout tapers 25 of the bars 24, 27 so that the stampers 17 are detachable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for attaching and detaching a stamper having a transfer surface having a mold structure for injection molding and a drawing pattern.

[0002]

2. Description of the Related Art As a stamper having a transfer surface having a drawing pattern, a light guide plate used for a liquid crystal display plate for a laptop personal computer or a liquid crystal display device for irradiating a liquid crystal cell for a mobile phone from the back is used for brightness. There is a stamper or the like that transfers a drawing pattern having various irregularities as a plurality of fine dots for achieving uniformization of the above, and is currently manufactured and used.

When molding a molded product such as a light guide plate having such a drawing pattern, a stamper for transferring the uneven shape to the molded product such as the light guide plate is attached to one of a fixed mold and a movable mold and placed in the cavity. PM for light guide plate
It is manufactured by injection-filling a molten resin such as MA (Poly methyl Meth acrylate).

When such resin molding is performed, volatile gas and fine solid impurities contained in the molten resin injected into the cavity enter between the stamper mounting surface of the mold and the stamper, and the gas pressure thereof is increased. By the action of injection and filling pressure and the action of polishing solid impurities, the stamper mounting surface of the die and the back surface of the stamper are locally peeled off, causing a rough skin phenomenon. Further, for example, when a molten resin having a high temperature of about 300 ° C. is injected and filled into a mold cavity having a surface temperature of about 80 ° C., the stamper has a front surface of 300 ° C. and a back surface of 80 ° C. Since the stamper is pressed, the stamper moves along the stamper mounting surface of the mold by the expansion and contraction effect of heat and this pressure each time injection filling is performed, and the stamper mounting surface and the back surface of the stamper are abraded by friction.

However, the mold is an expensive device and requires permanent wear resistance. However, when the stamper replicates about 200,000 molded products such as a light guide plate, the transferability of the transfer surface having unevenness is improved. Since it will be damaged and will be replaced with a new stamper each time, it is sufficient if it has wear resistance within that range.Therefore, the mold is a common device and has high wear resistance, Is preferably a material having abrasion resistance to such an extent that it can be used until the transferability deteriorates without abrading the mold contact surface.

[0006] Therefore, the material of the molds generally used is plastic mold steel, and the fixed or movable stamper mounting surface is subjected to quenching and tempering treatment to be finished into a mirror surface state. However, in order to extend the service life of the mold and to provide high-precision molded products, in addition to this, carbides such as TiC and SiC that have wear resistance on the stamper mounting surface and nitriding such as TiN and SiN are also used. There are dies with hard layers such as things applied by chemical vapor deposition, and dies with diamond-like thin films with wear resistance, corrosion resistance and low friction properties evenly formed on the stamper mounting surface by ion vapor deposition etc. . When using the molds, the stamper mounting surfaces of these molds are also mirror-finished.

Although various metals can be used as the stamper material, nickel (Ni) is used in terms of mechanical performance and material uniformity.
Is a preferred material and is generally accepted because of the relationship between die wear resistance, corrosion resistance and low friction.
When the stamper is used, the stamper surface that contacts the stamper mounting surface of the mold is finished to be a mirror surface.

As a method of etching the drawing pattern on the stamper master having the above material, there are various dry etching methods other than the wet etching, and the ion milling method is particularly preferably used.

By the way, as a conventional exchanging device for a light guide plate stamper, there is provided a plate material in which a corresponding pattern for forming a brightness improving pattern is engraved, that is, a brightness improving pattern in Japanese Patent Application Laid-Open No. 8-6017. A stamper having a transfer surface is exchanged by directly attaching and detaching the stamper with six mounting bolts, and in Japanese Patent Laid-Open No. 9-131770, a groove or hole is formed on the surface of the die member, It is disclosed that a stamper having a thickness of 0.1 to 0.6 mm and having a transfer surface provided with the optical pattern of the light guide plate from the groove or hole is attached to the mold member by vacuum suction.

Further, in JP-A-11-58464, a light guide plate forming cavity is formed by a bottom surface forming cavity mounted on a movable mold, four end face forming cavities, and a fixed mold, and further, among them, A pair of end face forming cavities each having a surface with a molding draft are fitted with two ejector blocks each having a similar molding draft on the cavity surface for protruding the light guide plate from the mold at the time of mold release. The ejector block is formed with a hook-shaped part that fixes a stamper with a thickness of about several mm, and the light guide plate is projected by the draft of the ejector block at the time of mold release, and the hook-shaped part of this ejector block is used at the time of mold clamping. The bottom face shape is configured to fix the stamper and press the stamper against the bottom face forming cavity, and to abut against another pair of end face forming cavities. In the mold structure in which each stamper positioning block is provided in the cavity portion and the stamper positioning block is provided with the cutout portion in consideration of thermal contraction and thermal expansion, when exchanging the stamper, when the stamper is replaced, the four end face forming cavities are formed. A stamper exchanging mechanism which removes four ejector blocks is disclosed.

[0011]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In an injection molding die in which a stamper is mounted on the surface forming the die cavity as described above, the volatile gas and fine solid impurities contained in the molten resin are not contained in the die. Each time the surface of the cavity and the back surface of the stamper come into contact with each other, roughening occurs on those contact surfaces during injection molding, and every time the molten resin is injected and filled into the cavity, the heat of the high temperature molten resin and the low temperature Since the contact surface of the stamper is abraded by friction due to the expansion and contraction of the stamper due to the heat of the mold, the surface that constitutes the mold cavity is a diamond-like thin film with high hardness wear resistance, corrosion resistance and low friction. The surface of the stamper is harder than the hardness of the backside of the stamper, and the surface is roughened by volatile gas and fine solid impurities, and the heat is generated by expansion and contraction. And constructed as to inflict all at any time replaceable stamper. Further, the stamper, when about 200,000 molded products such as a light guide plate are duplicated, has a frictional resistance force due to the viscosity generated by the molten resin flowing on the transfer surface and a frictional force generated by the adhesion of the resin at the time of mold release. Therefore, the transfer surface having irregularities is abraded and the transferability is impaired, so that replacement is generally performed regularly for planned maintenance.

In addition to the above, not only is it necessary to quickly and easily and reliably perform stamper replacement that occurs accidentally due to damage or damage to the stamper, or deformation due to molding pressure, etc., during molding. The same applies to the case where the transfer surface is regularly replaced due to wear or the like.

In the conventional stamper replacement method, the technique disclosed in Japanese Patent Laid-Open No. 8-6017 is to replace the six bolts by directly attaching and detaching them to and from the mold. However, there is a problem that the mounting becomes inaccurate due to bolt tightening, or the mounting position is displaced or disengaged due to loosening of the bolt, resulting in defective molding or damage to the stamper. In the technique described in Japanese Patent Laid-Open No. 9-131770, a stamper is vacuum-adsorbed and mounted on a mold member, and a volatile gas of a molten resin and fine solid impurities are adsorbed on a contact surface with the mold. Not only there is the problem that defects easily occur, the stamper comes off, the mounting position shifts, and molding defects also occur due to deformation of the stamper, etc., equipment for vacuum suction is required, and the device becomes complicated, There is also the problem of high costs.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 11-58464, a cavity is formed by a bottom face forming cavity mounted on a movable mold, four end face forming cavities and a fixed mold, and a pair of end faces is formed. Two ejector blocks are fitted in each forming cavity, and a hook-shaped part for fixing the stamper is formed on this ejector block. The light guide plate is projected by the ejector block when releasing the mold, and the hook-shaped part of this ejector block is clamped. It is configured to fix the stamper at the part and to press the stamper against the bottom surface forming cavity.
It is necessary to remove the cavity for forming the end face of the surface and the four ejector blocks, and the mechanism is complicated and the cost is high. Moreover, there is a problem that it takes a lot of time to replace the stamper. Furthermore, since the stamper positioning block provided in the bottom surface forming cavity is provided with cutouts for thermal contraction and thermal expansion, when molded with different resin materials, the thermal expansion of the stamper also differs because the melting temperature differs depending on the type of resin. There is also a problem that the mounting position of the stamper becomes unstable and uneven transfer occurs on the surface of the molded product, resulting in defective molding.

Therefore, the present invention has been made in view of the above circumstances, and prevents the expansion and contraction of the stamper due to the heat of the molten resin and the instability of the mounting position due to the filling pressure, without exchanging the mold. An object of the present invention is to provide a mold structure that allows quick and easy and reliable replacement of stampers.

[0016]

In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is a stamper having a transfer surface having a drawing pattern for transferring to the surface of a molded article. And a mechanism for allowing the stamper to be attached and detached so that the surface not having the transfer surface is in close contact with one or both of the surface forming the cavity of the fixed mold and the surface forming the cavity of the movable mold. In the injection mold, the rotational force around the drive shaft, which is attached to the inside or the outer peripheral surface of the mold and is rotated manually,
A plurality of stamper pressing members having drive means for converting into linear moving force and at least one upper and lower side of the surface forming the mold cavity and at least one side of the left and right sides of the claw portion for preventing the stamper from falling off; A moving means for moving the mold in the inner and outer peripheral directions is provided in conjunction with the driving means.

According to the present invention, with this structure, the stamper can be attached and detached to and from the surface forming the mold cavity portion safely and quickly, and the stamper can be attached accurately. It is intended to provide a mounting structure.

According to a second aspect of the present invention, in order to position the stamper on the surface forming the mold cavity portion, a biasing means for pressing the stamper in the inner peripheral direction of the mold is provided. It is characterized by being provided.

According to a third aspect of the present invention, in the biasing means, when the molten resin is filled in the mold cavity, the stamper is locked against the filling pressure of the resin, Alternatively, it is characterized by urging so as to absorb the thermal expansion of the stamper due to the heat of the molten resin.

The object of the present invention is to provide a molded product of high precision and high quality by preventing uneven transfer and defective molding of the molded product by configuring as described above.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a front view of a stamper exchanging device 20 according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of the drive unit 30 when viewed from the arrow X in FIG. FIG. 3 is a view showing a state in which the stamper 17 is attached. FIG. 4 is a view showing that the stamper 17 is in a replaceable state. FIG. 5 is a cross-sectional view of the mold formed when the fixed mold 10 and the movable mold 40 are closed when viewed from the arrow YY of FIG. The mounting structure of the stamper 17 will be described in detail below with reference to FIGS.

In FIG. 1, a rectangular stamper 17 is mounted in the fixed mold 10, and a plurality of fixed stamper pressing members 21 are provided on the lower and left sides of the fixed mold 10 in order to prevent the stamper 17 from falling. It is fixed to the fixed mold 10 with a plurality of bolts 22. Then, a mounting space 60 for the stamper exchanging device 20 is provided on the surface facing the surface on which the fixed stamper pressing member 21 is fixed, and the stamper 17 is provided.
A stamper exchanging device 20 for easily attaching and detaching the device is provided.

The stamper exchanging device 20 includes a plurality of movable stamper pressing members 23 for easily attaching and detaching the stamper 17, a plurality of cutout taper portions 25, and a slide bar 24 having rack teeth 26 at one end. 27, guide members 28a, 28b and 29 for slidably guiding the movable stamper holding member 23 and the slide bars 24, 27.
And the guide members 28a, 28b and 29 to the fixed mold 10
A plurality of bolts 18 for attaching the movable stamper holding member 23 to the cutout taper portion 25 of the slide bar 24, and a plurality of springs 19 for applying a biasing force to the slide bar 24, and rack teeth 26 of the slide bars 24, 27. And the involute gear 31 mesh with each other, and the involute gear 3
It is composed of a drive unit 30 that moves the slide bars 24 and 27 by a predetermined amount with the rotation of 1. The guide member 29
Also serves as a retainer for the involute gear 31 and the center of rotation of the drive unit 30.

Further, as shown in FIG. 2, the drive unit 30 has a drive shaft 33 in which an involute gear 31 and a direct bevel gear 32 are integrally connected to the center of rotation of the involute gear 31, and the drive shaft 33 can freely rotate. Two sets of bearings 34 arranged between the involute gear 31 and the immediate bevel gear 32 and at the end opposite to the involute gear 31;
Snap ring 35 for fixing bearing 34
A drive shaft 37 integrally connected to the center of rotation of the immediate bevel gear 36, and two sets of two arranged so as to maintain the axis of the immediate bevel gear 36 so as to freely rotate the drive shaft 37. The bearing 38, the snap ring 39 for fixing the bearing 38, the bracket 41 that is preferably attached to achieve the normal meshing of the direct bevel gear 32 and the direct bevel gear 36, and the bracket 41 are fixed. Bolts 42 and 43 for attaching to the side surface of the mold 10 and the drive shaft 37
Is rotated freely and after mounting the stamper 17, the drive shaft fixing member 44 for fixing the drive shaft 37 so that the stamper exchanging device 20 remains stationary during injection molding, and the drive shaft fixing member 44 on the bracket 41. Drive shaft 3 at the same time as mounting
It is composed of a bolt 45 for fixing the non-rotatable member 7 and a handle 46 for rotating the drive shaft 37 for attaching / detaching the stamper 17. The handle 46 attachment portion of the drive shaft 37 is formed in a square shape.

Next, the operating mechanism of the present invention will be described. In FIG. 1, since the stamper 17 is mounted, the state will be described first. From FIG. 2, the drive shaft 37
Loosen the two bolts 45 so that the can rotate freely.
Next, when the handle 46 is inserted into the end of the drive shaft 37 formed in a square shape and rotated in the B direction, the rotational driving force of the straight bevel gear 36 fixed to the drive shaft 37 is fixed to the drive shaft 33. Drive shaft 3 through meshing with bevel gear 32
Propagate to 3. At this time, by using the bevel gears 32 and 36, the rotation shaft changes from the left-right direction in FIG. As a result, the drive shaft 3
The direction of rotation of the involute gear 31 fixed to No. 3 is shown in FIG.
The rotational drive force transmitted to the drive shaft 33 is in the B direction at the slide bar 2 meshed with the involute gear 31.
It is transmitted to the rack teeth 26 of Nos. 4 and 27 and is converted into a driving force that makes a linear movement in the E direction. At this time, slide bar 2
4 and the slide bar 27 are guide members 28a, 28b and 29 for slidably guiding the slide bars 24 and 27 in the E direction so as to be orthogonal to each other while keeping a slight gap.
And a predetermined amount D along the guide surfaces 52a to 52e of the fixed mold 10.
Slide. In other words, the mounting holes 15, 1 as shown in FIG.
The movable stamper pressing member 23, which is pressed by the urging force of the spring 19 assembled in a state where a predetermined amount of pre-compression is applied by fitting both ends with respect to 6, is notched in the slide bars 24, 27. From the state in which the stamper 17 is mounted by pressing it slightly above the surface of the tapered portion 25, the movable stamper holding member 23 resists the urging force of the spring 19 and the moving slide bar 2 moves.
After abutting against the notched taper portions 25 of Nos. 4, 27, while sliding on the upper surface of the notched taper portions 25, the slide bars 24, 27 are slid by a predetermined amount D, that is, the guide members 28a, 28b and 29 guide surfaces 51a (5
1c, 51f), 51b (51d, 51e) by a predetermined amount C
Only by sliding in the outer peripheral direction of the fixed mold 10, the stamper 17 is in the removable state shown in FIG. The required amount of movement of the movable stamper pressing member 23 against the urging force of the spring 19 may be an amount such that the stamper 17 can be easily replaced at the above C or higher. Further, in order for the movable stamper pressing member 23 to slide well on the upper surface of the notched taper portion 25 of the moving slide bars 24 and 27,
As shown in FIG. 4, the taper angle α of the slide bars 24 and 27 and the inclination angle α of the slide surface of the movable stamper holding member 23 need to match.

Then, after the stamper 17 is replaced, the handle 46 is rotated in the A direction this time, and the rotation direction of the involute gear 31 integrally connected to the rotation center of the drive shaft 33 is the A direction in FIG. The rotational driving force transmitted to the shaft 33 is transmitted to the rack teeth 26 of the slide bars 24 and 27 meshing with the involute gear 31, and is converted into a driving force for linearly moving the slide bars 24 and 27 in the F direction. It Then, the guide members 28a, 28b and 29
When the slide bars 24 and 27 move a predetermined amount D in the F direction along the guide surfaces 52a to 52e of the fixed mold 10, the stamper 17 is completely mounted. That is, from the state of FIG. 4 in which the stamper 17 is not attached, the movable stamper pressing member 23 is pressed while being pressed by the urging force of the spring 19.
, While sliding on the upper surface of the notched taper portion 25 of the slide bars 24, 27 moving in the F direction, a predetermined amount D
When it reaches the vicinity, it slightly floats from the notched taper portion 25 and moves a predetermined amount D. That is, the movable stamper pressing member 23 is pressed by the biasing force of the spring 19 and the movable stamper pressing member 23 guides the guide surfaces 51a (51c, 51f), 51b (51d, 51) of the guide members 28a, 28b and 29.
When e) is slid in the inner circumferential direction of the fixed mold 10 by a predetermined amount C, the stamper 17 is mounted in the state shown in FIG. At this time, the movable stamper holding member 23 is moved to the slide bar 2
The stamper 17 is slightly lifted from the surface of the notched taper portion 25 of the Nos. 4 and 27, and the stamper 17 is brought into contact with the stamper contact surface 23b of the movable stamper pressing member 23 and the stamper contact of the fixed stamper pressing member 21 by the urging force of the spring 19. While sandwiched by the surface 21b, as shown in FIG. 5, a slight gap (20 μm to 50 μm) is formed between the stamper and the transfer surface so that the stamper can slide even when the stamper thermally expands and no burr of the molten resin occurs. The claw portion 23a of the movable stamper holding member 23 and the claw portion 21a of the fixed stamper holding member 21 prevent the stamper 17 from falling off. In order to maintain this state during molding, the drive shaft 37 is fixed by the bracket 41 and the drive shaft fixing member 44 via the two bolts 45, and the drive shaft 37 is made non-rotatable. , 27 are stopped. Finally, the handle 46 is removed to complete the work.

A flange 77 is provided on the side portion of the guide members 28a, 28b and 29 fixed to the fixed mold 10 with a plurality of bolts 18 so that the movable stamper holding member 23 does not fall off. Type stamper pressing member 23
Are provided on both sides with groove portions 78 that come into contact with these flange portions 77, and the movable stamper holding member 23 is
The guide surfaces 51a (51c, 51f), so as not to fall off while being pressed by the guide members 28a, 28b and 29,
It is slidably arranged along 51b (51d, 51e).

By the way, in FIG. 5, a molded product 11 (cavity 12) of a light guide plate, a stamper exchanging device 20 and a stamper 17 which constitute a backside illumination type liquid crystal display device as the above-mentioned embodiment of the present invention are mounted and fixed metal. Mold 10 and movable mold 40
A mold cross-sectional view when the mold is closed is shown. The light guide plate molded product 11 is molded by injection molding using a conventionally known material such as methacrylic resin (PMMA). The mold used in this embodiment is a hot runner type, and the molten resin is fed from the nozzle 71 to the hot runner 73 and the sprue 74 in the fixed mold 10, and the runner 75 and the gate 76 in the movable mold 40. The cavity 12 is injection-filled via the above, and the molded product 11 of the light guide plate is molded. At this time, a plurality of heaters 72 are embedded around the hot runner 73 to prevent the temperature of the molten resin from decreasing.

The stamper 17 sandwiched between the fixed stamper pressing member 21 and the movable stamper pressing member 23 pressed by the spring 19 is a mirror surface and a surface having a transfer surface with which molten resin comes into contact when injection-filled. Since there is a temperature difference between the finished surface and the mounting surface to the fixed mold 10, the stamper 17 thermally expands. As a result, the movable stamper pressing member 23 resists the pressing force of the spring 19 and slightly moves in the outer peripheral direction of the fixed mold 10 by the amount of thermal expansion. The amount of movement of this thermal expansion depends on the shape and material of the stamper 17, but in general, it is a value that is considerably smaller than the amount of movement C when the stamper 17 is replaced. It is not necessary to secure a moving space for the movable stamper holding member 23.

In this embodiment, the mounting surfaces of the stamper 17 and the stamper 17 of the fixed mold 10 are the stamper 1
The abrasion due to the thermal expansion of 7 and the polishing action caused by the volatile gas and fine solid impurities contained in the molten resin when the molten resin is filled in the cavity 12 causes abrasion. Is a Ni (nickel) material, and the stamper 17 mounting surface of the fixed mold 10 is provided with a diamond-like thin film having uniform wear resistance, corrosion resistance and low friction, which is formed by an ion deposition method or the like,
The stamper 17 is treated as a consumable item so that the mounting surface of the stamper 17 on the fixed mold 10 is worn when the transferability of the stamper 17 is poor, and the fixed mold 10 is not worn and can be used semipermanently. This is done by configuring.

From the above embodiment, according to the present invention, a plurality of fixed stamper pressing members 21 are fixed to the lower portion and the left side portion of the fixed mold 10, and the stamper 17 is mounted thereon. Then, by rotating the handle 46, the stamper exchanging device 2
The rotational force transmitted through the gear mechanism of the drive unit 30 attached to the inside of the rack 0 is applied to the rack teeth 26 of the slide bars 24 and 27.
The force is converted into a linearly reciprocating force through the slide bar 24, and the movable stamper pressing member 23 pressed by the biasing force of the spring 19 is fixed by utilizing the inclined surface of the notch taper portion 25 of the slide bars 24 and 27. A stamper exchanging device 20 configured such that the stamper 17 can be detachably moved by moving the die 10 in the inner and outer peripheral directions. According to the present device, a filling pressure generated when the molten resin is injected into the cavity 12 is filled. The stamper 17 is prevented from being displaced by pressing the movable stamper pressing member 23 by the urging force of the spring 19 whose both ends are supported by the mounting holes 15 and 16, respectively. The expansion and contraction due to heat is dealt with by moving the movable stamper pressing member 23 pressed by the urging force of the spring 19 in the inner and outer peripheral directions of the fixed mold 10. It is configured so that.

As described above, the present apparatus receives the expansion and contraction action by the heat of the stamper 17 due to the heating of the molten resin while preventing the stamper 17 from being displaced due to the filling pressure that occurs when the molten resin is injected and filled in the cavity 12. Since the stamper 17 can be surely attached even when the molded article is pressed, it is possible to prevent uneven transfer of the molded article and defective molding, and it is possible to obtain a highly accurate and high-quality molded article. Further, by configuring this apparatus as described above, periodical replacement due to deterioration of the transfer surface of the stamper 17, wear at the contact surface between the stamper 17 and the fixed mold 10, volatile gas contained in the molten resin, and fine particles It is possible to quickly and easily and surely perform the replacement due to the rough skin phenomenon caused by the solid impurities and the accidental replacement due to the damage or damage to the stamper 17 or the deformation due to the molding pressure.

In another embodiment, the spring 1 is
Without using the urging force of 9, the slide bar 24, 27 is provided with several grooves with a width of several mm having the same inclination angle α as the inclination angle α of the notch taper portion 25 of the slide bar 24, 27, and the movable stamper holder is held. A slide member having a convex shape is set on the member 23 so as to be fitted in the groove, and the slide bar 2
It is also possible to move the movable stamper pressing member 23 in the inner and outer peripheral directions of the fixed mold 10 along with the movement of 4, 27 to make the stamper 17 detachable.

Aspects and technical features of the present invention include a plurality of fixed stamper pressing members 21 fixed to the lower part and the left side of the fixed mold 10 for fixing the stamper 17,
The stamper 17 is configured to be attachable / detachable by the fixed stamper pressing member 21 and the stamper exchanging device 20 provided on the surface facing the fixed stamper pressing member 21. The stamper pressing member 21 is entirely replaced with the movable stamper pressing member 23, and rack teeth 26 are provided at the ends of the slide bars 24 and 27 opposite to the rack teeth 26. Involute gear 31 rotatably so as to mesh with teeth 26
Are arranged at the upper left and lower right of FIG. Then, the slide bars 24, 27 having rack teeth at both ends so as to mesh with the involute gears 31 and arranged in FIG. 1 are rotated by 180 ° around the central axis of the fixed mold 10, and new slide bars are provided. The movable stamper pressing member 23 arranged around the entire circumference of the fixed mold 10 is fixed to the fixed mold 10 by rotating the handle 46 attached to the drive unit 30.
The stamper 17 can be configured to be removable by moving the stamper 17 in the inner and outer circumferential directions, or the stamper 17 can be configured to be removable by arranging the slide bars 24 and 27 in a polygonal shape. In addition, these mechanisms are attached to the fixed mold 10
It can be mounted on each of the movable mold 40 and the movable mold 40, or on both of them. Therefore, although not enumerated one by one, the present invention is not limited to the above description, but is described in the entire specification and drawings, or is recognized based on an idea thought by those skilled in the art from the description. It should be understood that it is a thing.

[0035]

As shown and described above, according to the present invention, the stamper 17 is prevented from being displaced due to the filling pressure, and the stamper 17 is set to a predetermined size even when the molten resin is subjected to the expansion and contraction action. Since it can be reliably mounted at the position, it is possible to prevent uneven transfer of the molded product and defective molding, and it is possible to obtain a high-precision and high-quality light guide plate by molding. Furthermore, without changing the mold, the transfer surface of the stamper 17 is deteriorated, the contact surface with the fixed mold 10 is abraded, the volatile gas contained in the molten resin and the fine solid impurities cause a rough surface phenomenon, scratches and damages. Regular or accidental replacement of the stamper 17 due to deformation due to molding pressure or the like can be performed quickly and easily and reliably, so that the stamper 17 can be replaced reasonably and economically. is there.

[Brief description of drawings]

FIG. 1 is a front view of a stamper exchanging device 20 according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a drive unit 30 when viewed from an arrow X in FIG.

FIG. 3 is a view showing a state in which a stamper 17 is attached in FIG.

FIG. 4 is a view showing that the stamper 17 in FIG. 1 is in a replaceable state.

5 is a cross-sectional view of the mold formed by the fixed mold 10 and the movable mold 40 when the mold is closed as viewed from the arrow YY of FIG.

[Explanation of symbols]

10 ... Fixed mold 11 ・ ・ ・ Molded light guide plate 12 Cavity 15, 16 ... Mounting hole 17 ... Stamper 18, 22, 42, 43, 45 ... Bolt 19 ... Spring 20 ... Stamper exchange device 21 ... Fixed stamper holding member 21a, 23a ... claws 21b, 23b ... Stamper contact surface 23 Movable stamper holding member 24, 27 ... Slide bar 25 ... Notched taper part 26 ・ ・ ・ Rack teeth 28a, 28b, 29 ... Guide member 30 Drive unit 31 Involute gear 32,36 ・ ・ ・ Immediately bevel gear 33, 37 ··· Drive shaft 34, 38 Bearings 35, 39 ・ ・ ・ Snap ring 40 ... movable mold 41 ... Bracket 44 ... Drive shaft fixing member 46 ………… Handle 51a-f, 52a-e ... Guide surface 60 ... Installation space 71 ... Nozzle 72 ... Heater 73 ... Hot Runner 74 ... Sprue 75 Runner 76 ... Gate 77 ‥‥ 78 ... Groove

Claims (3)

[Claims] 1. A surface of a stamper having a transfer surface provided with a drawing pattern for transferring to a surface of a molded product, a surface of the stamper which does not have the transfer surface, and a cavity of a movable mold. In an injection-molding die having a mechanism that allows the stamper to be attached and detached so as to be in close contact with one or both of the surfaces that form the part, it is attached to the inside or the outer peripheral surface of the die and is obtained by manually rotating. Drive means for converting a rotational force around a drive axis into a linear movement force, and a claw for preventing the stamper from falling off at least on one side and at least one side of a surface forming the mold cavity portion A stamper holding member having a plurality of parts, and moving means for moving the stamper holding members having the parts in the inner and outer peripheral directions of the mold in cooperation with the driving means. Attached structure. 2. The urging means for pressing the stamper in the inner circumferential direction of the mold in order to position the stamper on the surface forming the mold cavity portion. The stamper mounting structure shown. 3. The stamper is locked against the resin filling pressure when the molten resin is filled in the mold cavity,
Alternatively, the stamper mounting method in the mold according to claim 2, wherein the stamper is biased so as to absorb thermal expansion of the stamper due to heat of the molten resin.