JP2010221691A - Mold for long molded article and method for manufacturing long molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the trace of an ejector adheres to a long molded article when the long molded article in a cavity is projected by the ejector provided in the cavity. <P>SOLUTION: In a mold for a long molded article forming a long cavity, a runner communicated with one end in a longitudinal direction of this cavity and a resin reservoir communicated with another end in a longitudinal direction of this cavity in combination of a moving mold and a fixed mold, an ejector is provided on the runner and the resin reservoir on the moving mold side to project the molded article of the molten resin cooled and solidified in the runner and the reservoir by the ejector, thereby extracting the long molded article the molten resin cooled and solidified in the cavity on the moving mold side from the moving mold. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a mold for a long molded product for molding a long molded product such as a magnet piece used in a magnet roll used in an image forming apparatus such as a laser printer or a digital copying machine, and a long molded product It relates to the manufacturing method.

  As shown in FIGS. 8 and 9, conventionally, the shape of the cross section (transverse section) in the short direction around the shaft 52 is substantially fan-shaped, and the area of the cross section is in the longitudinal direction (axial direction of the shaft 52). There is provided a magnet roll 51 in which a plurality of substantially uniform magnet pieces (elongated molded products) 53 to 58 are bonded together radially using an adhesive or the like (see, for example, Patent Documents 1 to 7).

  As shown in FIG. 8, the magnet roll 51 includes a magnet piece 55 of a pumping pole S3 (S pole), a magnet piece 54 of a trimming pole N2 (N pole), and a developing pole S1 (S) around a shaft 52. Pole) magnet piece 53, recovery (conveyance) pole N1 (N pole) magnet piece 58, peeling pole S2 (S pole) magnet piece 57, and interposition pole piece 56 (S pole) in this order. It is the one that was made (laminated).

  These magnet pieces 53 to 58 are manufactured by molding in a magnetic field using a magnetic resin material made of a mixture of magnet material powder, resin binder, additive and the like.

  As the magnet material powder, for example, a mixture of ferrite powder, rare earth metal powder such as Nd, and iron group metal powder such as Fe, Co, and Ni can be used. As the resin binder, for example, polyamide, polyethylene, polypropylene, epoxy resin, ethylene ethyl acrylate (EEA), or the like can be used.

  As shown in FIG. 10, the individual magnet pieces 53 to 58 used for the so-called bonded magnet roll 51 include a fixed die 64 having an orientation yoke 68 and a movable die having an ejector 69. The melted magnetic resin material is injected from a runner (not shown) that communicates with one end in the longitudinal direction of the cavity 65 formed in combination with 63, and the magnetic resin material filled in the cavity 65 is cooled and solidified. (For example, see Patent Document 8).

  Here, the cavity refers to a space inside the mold (a space having the shape of an injection molded product), and the cavity surface refers to the surface of the mold that forms the cavity. Communication means making two spaces into a continuous state.

  The magnet piece 70 in the cavity 65 is opened by moving the movable die 63 relative to the fixed die 64 as shown in FIG. 11, and the ejector 69 is moved to the movable die 63 side as shown in FIG. It can be taken out from the movable mold 63 by protruding into the cavity (for example, see Patent Document 9).

JP 2003-229309 A JP 2003-229321 A JP 2001-034068 A JP 2000-077565 JP-A-10-308308 Japanese Patent Laid-Open No. 01-114011 JP-A-62-282422 JP 2003-229321 A Japanese Patent Laid-Open No. 10-270277

  However, at the production site of the molded product, for the purpose of shortening the production tact and increasing the production amount of the magnet piece 70, the mold is opened in a state where the molten resin is not completely cooled and solidified in the cavity 65, and the ejector 69 is ejected. In general, the magnet piece 70 is taken out of the mold. For this reason, as shown in FIG. 13, the magnet piece 70 has a problem that a mark 75 of the ejector 69 is attached.

  Thus, when the mark 75 of the ejector 69 is attached to the magnet piece 70, the density of the magnetic resin material in the vicinity of the mark 75 is different from that of the other parts, so that the magnetic field in the vicinity of the mark 75 is disturbed.

  Further, since the periphery of the trace 75 is slightly raised as compared with other portions, there is a problem that the portion of the trace 75 floats from the shaft 52 when the magnet piece 70 is bonded to the peripheral surface of the shaft 52.

  The present invention has been made to solve such a problem, and it is an object of the present invention to provide a method for producing a long molded article having no ejector trace and a mold for the long molded article.

(First invention)
The first invention is a combination of a movable mold and a fixed mold, whereby a long cavity, a runner communicated with one end in the longitudinal direction of the cavity via a gate, and a resin communicated with the other longitudinal end of the cavity The present invention relates to a mold for a long molded product in which a reservoir is formed.

  Here, “communication” means that two separated spaces are in a continuous state via a passage. That is, in the long molded product mold according to the first invention, one end of the cavity and the runner are connected via the gate, and the other end of the cavity and the resin reservoir are connected.

  In the long molded product mold according to the first aspect of the present invention, the movable mold side runner and the resin reservoir are provided with ejectors, and the long molded product is not provided with the ejector. . For this reason, after moving the movable mold away from the fixed mold and opening the mold, the molded product formed by cooling and solidifying the molten resin in the runner and the resin reservoir is ejected by the ejector. The long molded product in which the molten resin in the side cavity is cooled and solidified is taken out from the movable mold.

  Here, the molded product is a generic term for a material in which the molten resin is cooled and solidified in the runner and the resin reservoir, and excludes a long molded product in which the molten resin is cooled and solidified in the cavity. Is. The gate is a port for injecting molten resin into the cavity.

With such a configuration, since the long molded product does not hit the ejector, it is possible to manufacture a long molded product that does not have an ejector mark.
For this reason, when the long molded product is a magnet piece, the magnet piece can be bonded to the shaft without floating (no gap between the shaft and the magnet piece).
More specifically, when an ejector is provided so as to be able to protrude into the cavity, the contact portion with the movable ejector is worn due to the entrance and exit of the ejector. The molten resin enters the worn portion, and burrs are generated in the long molded product. However, since the long molded product mold according to the first invention does not have an ejector in the cavity, no burrs are generated in the long molded product.

  In addition, since there is no ejector mark on the long molded product, when the long molded product is a magnet piece, there is no disturbance of the magnetic field near the ejector track, and the magnetic field generated on the surface (arc surface) extends in the longitudinal direction. And stable magnet pieces can be provided.

(Second invention)
The second invention is a combination of a movable mold and a stationary mold made of a nonmagnetic material (nonmagnetic steel), a long cavity, a runner communicating with one end in the longitudinal direction of the cavity via a gate, and the cavity A resin reservoir communicating with the other end in the longitudinal direction is formed, an alignment yoke for aligning and magnetizing the magnetic powder of the molten resin in the cavity is disposed in the fixed mold, and the molten resin is cooled and solidified in the movable mold The present invention relates to a mold for a long molded product provided with an ejector for taking out a long molded product from a movable mold.

  The movable runner and the resin reservoir are provided with ejectors, and the molded resin in which the molten resin in the runner and the resin reservoir is cooled and solidified is ejected by the ejector so that the molten resin in the cavity is cooled and solidified. The molded product is taken out from the movable mold.

  Here, the molded product is a generic term for a molded product obtained by cooling and solidifying the molten resin in the runner and the resin reservoir, and excluding a long molded product formed by cooling and solidifying the molten resin in the cavity. Is.

With this configuration, the effect of the first invention described above can be obtained.
In addition, since both the movable mold and the stationary mold are made of non-magnetic steel, long molded products such as magnetized magnet pieces are not attracted to the movable mold or the stationary mold by magnetic force, and are not attached to the runner and the resin reservoir. A long molded product can be taken out of the mold with a certain ejector. That is, even if the long molded product is a magnet, the long molded product can be easily taken out from the mold without providing an ejector in the cavity.

(Third invention)
According to a third aspect of the present invention, there is provided a mold for a long molded product according to the first or second aspect of the present invention, wherein a protrusion that protrudes from the cavity is provided in the vicinity of the gate of the cavity on the movable mold side or the fixed mold side. Is gradually increased toward the other end in the longitudinal direction of the cavity.

  With this configuration, not only the effects of the first invention or the second invention are exhibited, but also when the molded product is ejected by the ejector, the long molded product can be reliably ejected together with the molded product from the movable mold.

  The effect of the third invention will be described in more detail. That is, when the molten resin injected into the cavity is cooled and solidified to form a long molded product, since the cavity is long, the long molded product in the cavity is greatly contracted in the longitudinal direction. And since the cross-sectional area of the gate is much smaller than the cross-sectional area of the long molded product, it is located at one end in the longitudinal direction of the cavity (the gate where the long molded product and the runner are connected) due to the shrinkage of the long molded product. In part), the long molded product and the runner may be separated.

  The resin reservoir at the other end in the longitudinal direction of the cavity has a cross-sectional area that gradually increases toward the other end in the longitudinal direction of the cavity. The molded product obtained by cooling and solidifying the molten resin in the resin reservoir portion is not separated from the long molded product.

  In this case, even if the runner is protruded by the ejector in the movable mold, the long molded product and the runner are separated from each other, so that one end on the gate side of the long molded product remains in the cavity on the movable mold side. There is a problem that a long molded product cannot be ejected.

  However, by adopting the configuration of the above-described third invention, since the projections enter the long molded product on the gate side (one end side) in the longitudinal direction of the long molded product, the long molded product is a gate. It cannot shrink in the direction away from it. For this reason, since the shrinkage in the longitudinal direction of the long molded product occurs on the other end side (the non-gate side) without the gate, the long molded product and the runner are not separated at the portion where the gate is located, and the molded product With the ejector, the long molded product can be reliably ejected together with the molded product.

(Fourth invention)
According to a fourth aspect of the present invention, there is provided a method for manufacturing a long molded article, comprising combining a movable die and a fixed die, a long cavity, a runner communicating with one end in the longitudinal direction of the cavity via a gate, Prepare a mold for a long molded product formed with a resin reservoir communicating with the other end in the longitudinal direction, and inject molten resin from the runner of the mold for the long molded product into the cavity and the resin reservoir, After the movable mold and the fixed mold are cooled and the molten resin is cooled and solidified, the movable mold is moved relative to the fixed mold to open the mold, and the molded product in which the molten resin in the runner and the resin reservoir is cooled and solidified is obtained. The long molded product in which the molten resin in the cavity is cooled and solidified is ejected from the movable mold by being ejected by an ejector provided on the movable mold, and then the molded product is cut. .

With this configuration, it is possible to manufacture a long molded product that does not have an ejector mark.
For this reason, when the long molded product is a magnet piece, the magnet piece can be bonded (attached) without floating with respect to the shaft (without a gap between the shaft and the magnet piece).
More specifically, when an ejector is provided so as to be able to protrude into the cavity, the contact portion with the movable ejector is worn due to the entrance and exit of the ejector. The molten resin enters the worn portion, and burrs are generated in the long molded product. However, since the long molded product mold according to the first invention does not have an ejector in the cavity, no burrs are generated in the long molded product.

  In addition, since there is no ejector mark on the long molded product, when the long molded product is a magnet piece, there is no disturbance of the magnetic field near the ejector track, and the magnetic field generated on the surface (arc surface) extends in the longitudinal direction. And stable magnet pieces can be provided.

(Fifth invention)
According to a fifth aspect of the present invention, there is provided a method for producing a long molded product, comprising a combination of a movable mold and a fixed mold made of a nonmagnetic material, and a runner communicating with a long cavity and one end in the longitudinal direction of the cavity via a gate. And a resin reservoir communicating with the other end in the longitudinal direction of the cavity is formed, an orientation yoke for orientation-magnetizing magnetic powder of molten resin in the cavity is disposed in the fixed mold, and the movable mold is melted. Prepare a mold for a long molded product with an ejector that takes out the long molded product that has cooled and solidified from the movable mold. From the runner of this mold for the long molded product, align it to the cavity and the resin reservoir. The molten resin is injected while being oriented and magnetized by the yoke, and the movable mold and the stationary mold are cooled and the molten resin is cooled and solidified. Then, the movable mold is moved to open the mold, and the runner and the resin reservoir The molded product melt resin is cooled and solidified, by projecting the ejectors provided in the movable mold, is taken out a long molded article molten resin cavity is cooled and solidified from the movable mold, it is to cut the molded product.

  Since the alignment yoke generates a magnetic force while a current is applied, it is desirable to cut off the current flowing through the alignment yoke when opening the mold.

  With this configuration, not only the effect of the third invention described above but also a long molded product such as a magnetized magnet piece can be taken out from the mold without being attracted to the movable mold or the fixed mold by a magnetic force.

(Sixth invention)
According to a sixth aspect of the present invention, in the method for producing a long molded product according to the fourth or fifth aspect of the present invention, the long molded product mold is further provided near the gate in the cavity on the movable mold side or the fixed mold side And a cross-sectional area of the resin reservoir is gradually increased toward the other end in the longitudinal direction of the cavity.

  With this configuration, not only the effects of the fourth invention or the fifth invention are exhibited, but also when the molded product is ejected by the ejector, the long molded product can be reliably ejected together with the molded product from the movable mold.

  By the long molded product mold and the long molded product manufacturing method according to the present invention, it is possible to manufacture a high quality long molded product with no trace of the ejector.

The perspective view of the metal mold | die for long molded articles which concerns on this invention Fixed type perspective view Movable perspective view Cross section of mold for long molded products Perspective view of long molded product Perspective view of magnet roll Cross section of developer carrier Side view of conventional magnet roll A perspective view of a conventional magnet roll Cross section of conventional mold Cross section of conventional mold Cross section of conventional mold Conventional magnet piece The perspective view of the metal mold | die for long molded articles which concerns on this invention Fixed type perspective view Movable perspective view Cross section of mold for long molded products Plan view (partially enlarged view) near the other end of the movable cavity 18 is a side sectional view (partially enlarged view) of FIG. Side sectional view (partially enlarged view) near one end of movable cavity Cross section of mold for long molded products

Hereinafter, the present invention will be described in detail using examples.
In addition, although the following example illustrates and demonstrates the magnet piece used with a magnet roll as a long molded article, it is not the meaning which interprets a long molded article limited to a magnet piece.
Further, the following embodiments will be described by taking up a molding die for one specific magnet piece among a plurality of magnet pieces used in a magnet roll, but the molding die for other magnet pieces is similarly described. It is composed.

The metal mold | die for long molded articles which concerns on this invention is demonstrated using FIGS. 1-4.
FIG. 4 is a cross-sectional view of a long molded product mold in which a movable mold and a fixed mold are combined when viewed from the side.
[Mold for long molded products]
As shown in FIGS. 1 and 4, the long molded product mold 21 according to the present invention includes a movable mold 13 and a fixed mold 14. A movable mold side cavity surface 19 and a fixed mold side cavity surface 20 are formed on the movable mold 13 and the fixed mold 14 respectively, and the cavity 30 is formed by combining the movable mold 13 and the fixed mold 14.

  The movable mold 13 has a movable mold side runner surface 22 and a resin reservoir surface 23, and the fixed mold 14 has a fixed mold side runner surface 24 and a resin reservoir surface 25. By combining the fixed mold 14, the resin reservoir 26 and the runner 18 are formed as shown in FIG. 4.

(Fixed type)
The fixed mold 14 is manufactured by cutting a non-magnetic material (non-magnetic steel) such as stainless steel. As shown in FIGS. 1 and 4, the fixed mold 14 is oriented with a magnet piece 3 as a long molded product. An orientation yoke 17 for magnetizing is provided.
(Movable type)
The movable mold 13 is manufactured by cutting nonmagnetic steel such as stainless steel. As shown in FIGS. 1 and 2, the movable mold 13 takes out the magnet piece 3 as a long molded product from the cavity on the movable mold side. Two ejectors 10 for this purpose are provided. Since one ejector 10 is provided in the movable mold side resin reservoir and the other is provided in the movable mold side runner, when the magnet piece 3 is taken out from the movable mold side cavity, the ejector 10 directly The magnet piece 3 is not projected. The magnet piece 3 is taken out from the cavity on the movable mold side when a runner connected to one end in the longitudinal direction and a resin reservoir connected to the other end, that is, a molded product is ejected by the ejector 10.

[Manufacturing method of long molded product]
First, a mold 21 for a long molded product is prepared by bringing the parting line surfaces 12 of the movable mold 13 and the fixed mold 14 into contact with each other, and the runner 18 directs the alignment to the cavity 30 and the resin reservoir 26. A fluidized molten resin material having magnetic powder (magnet material powder) is injected (injected) while being oriented and magnetized by the yoke.

  Then, after the cavity 30 and the resin reservoir 26 are filled with a molten resin material, cooling water is supplied to cooling water passages (not shown) provided in the movable mold 13 and the fixed mold 14 respectively, so that the movable mold 13 and the fixed mold 14 are filled. Cool down. Then, the molten resin material inside the runner 18, the cavity 30 and the resin reservoir 26 of the long molded product mold 21 is cooled and solidified.

  Thereafter, the movable mold 13 is moved away from the fixed mold 14 to open the mold. At this time, the cooled and solidified resin material (in which the long molded product 3 and the molded product 23 are integrated) is in the cavity on the movable mold 13 side. Therefore, as shown in FIG. 3, the long molded product 3 that has been cooled and solidified can be taken out of the movable die 13 by projecting the molded product 23 by the two ejectors 10 provided on the movable die 13.

  At both ends in the longitudinal direction of the magnet piece 3 as a long molded product, there is a molded product 23 in which the molten resin material in the runner 18 and the resin reservoir 26 is cooled and solidified. The magnet piece 3 can be obtained by cutting (removing) using.

  By using such a long molded product mold 21, the ejector 10 does not come into contact with a long molded product as a product, so that the product does not leave a mark of the ejector 10.

  Further, when the long molded product is a magnetic body having a magnetic force such as the magnet piece 3, the movable mold 13 and the fixed mold 14 are made of a non-magnetic rope, so that the magnet piece 3 is the movable mold 13 or the fixed mold. 14 is not attached. For this reason, the magnet piece 3 can be easily taken out without providing an ejector in the cavity on the movable mold side.

  The magnet pieces 3 to 8 as long molded products manufactured by the long molded product mold according to the present invention are fixed to the peripheral surface of the shaft 2 with an adhesive to form the magnet roll 1, and FIG. As shown in FIG. 4, the developer carrier 31 can be used by using a flange 33 in which both ends of the shaft 2 are supported by bearings 34 and a developing sleeve 37 in which the flange 33 is fixed at both ends.

Another embodiment will be described with reference to FIGS.
In order to make the explanation easy to understand, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.

[Mold for long molded products]
As shown in FIG. 14 and FIG. 17, the long mold product mold 73 according to the second embodiment is obtained by combining the movable mold 71 and the fixed mold 72, and the long cavity 30 and the longitudinal direction of the cavity 30. The runner 18 communicated with one end 80 via the gate 38 and the resin reservoir 77 communicated with the other end 81 in the longitudinal direction of the cavity 30 are formed.

  In the long molded product mold 73, the ejector 10 is provided in the runner 18 and the resin reservoir 77 on the movable mold 71 side, and a molded product obtained by cooling and solidifying the molten resin in the runner 18 and the resin reservoir 77 is obtained. The long molded product in which the molten resin in the cavity 30 on the movable mold 71 side is cooled and solidified is ejected from the movable mold 71 by being ejected by the ejector 10.

  Further, as shown in FIGS. 14, 16, and 20, the long molded product mold 73 according to the second embodiment has a cavity 30 (19) in the vicinity of the gate 38 in the cavity 19 on the movable mold 71 side. In addition to providing a protruding portion 78 that protrudes, the sectional area of the resin reservoir 77 is gradually increased toward the other end 81 in the longitudinal direction of the cavity 30.

Since the main difference from Example 1 is the protrusion part 78 and the resin reservoir part 77, these are demonstrated in detail.
(Protrusion 78)
As shown in FIG. 20, the projecting portion 78 is provided so as to project into the cavity 19 on the movable mold 71 side. When the long molded product in the cavity 19 on the movable mold 71 side is ejected together with the molded product in the mold opening direction of the movable mold 71 by the ejector 10, the long molded product is smooth from the projecting portion 78. The movable mold 71 is formed on the movable mold 71 so as not to undercut the mold opening direction of the movable mold 71. Here, the undercut refers to a portion that becomes caught in the mold opening direction when a long molded product is taken out from the injection mold.

  In the second embodiment, the protrusion 78 has a diameter of 1.5 mm (F = 1.5 mm in FIG. 20) and a height of 1.5 mm (FIG. 20) on the bottom surface of the cavity 19 on the movable die 71 side. E = 1.5 mm) was protruded. In addition, the G dimension in FIG. 20 should just be the thickness which does not lose to the heat shrink of a long molded product, and was set to 1.5 mm in the present Example 2. In addition, when the long molded product is a magnet piece, the position of the protrusion 78 is desirably provided within a range of 10 mm from one end 80 in the longitudinal direction of the cavity 30. This is because within such a range, the magnetic force uniformity in the longitudinal direction is hardly affected.

(Resin reservoir 77)
As shown in FIGS. 14 to 17, the resin reservoir 77 is formed by matching the resin reservoir 74 on the movable mold 71 side and the resin reservoir 75 on the fixed mold 72 side by closing the mold. Since the resin reservoirs 74 and 75 have the same configuration, the resin reservoir 74 will be described in detail.

  As shown in FIG. 18 and FIG. 19 (AA sectional view of FIG. 18), the resin reservoir 74 is configured so that the sectional area gradually increases toward the other end 81 of the cavity 19 on the movable mold 71 side. Has been. More specifically, in FIGS. 18 and 19, the width dimension is B <C <D and the height dimension is E <F <G from the end 82 of the resin reservoir 74 toward the other end 81 of the cavity 19. It is supposed to be. The positions of B and E, C and F, and D and G correspond to each other.

  With such a configuration, when the molten resin filled in the cavity 30 and the resin reservoir 77 is cooled and solidified to form a long molded product, the long molded product is formed on the one end 80 side of the cavity 30. Since the projecting portion 78 is inserted into the end portion 80, the one end 80 side of the long molded product cannot contract toward the other end 81 side of the cavity 30.

  However, since the resin reservoir 77 is configured on the other end 81 side of the long molded product as described above, the molded product formed inside the resin reservoir 77 and the long molded product connected to the molded product. The other end 81 side of the product can freely contract toward the one end 80 side of the cavity 30.

  For this reason, the molten resin in the cavity 30 is cooled and solidified, and the shrinkage of the long molded product when the long molded product is formed occurs exclusively at the other end 81 side of the cavity 30. Is not separated (cut) at the portion where the gate 38 is located, and the long molded product can be stably ejected from the movable die 71 by ejecting the molded product by the ejector 10.

[Manufacturing method of long molded product]
Next, a method of forming a long molded product using the above-described long molded product mold 73 will be described. First, a long molding die 73 in which the parting line surfaces 12 of the movable mold 71 and the fixed mold 72 are brought into contact with each other is prepared, and the runner 18 directs the cavity 30 and the resin reservoir 77 to the orientation. A fluidized molten resin material having magnetic powder (magnet material powder) is injected (injected) while being oriented and magnetized by the yoke.

  Then, after the cavity 30 and the resin reservoir 77 are filled with the molten resin material, cooling water is supplied to cooling water passages (not shown) provided in the movable mold 71 and the fixed mold 72, respectively. Cool down. Then, the molten resin material in the runner 18, the cavity 30 and the resin reservoir 77 of the long molded product mold 73 is cooled and solidified to form a long molded product.

At this time, as described above, the molded product and the long molded product formed inside the runner 18 are not separated by contraction of the long molded product.
Thereafter, the movable mold 71 is moved relative to the fixed mold 72 to perform mold opening. At this time, the cooled and solidified resin material (one in which the long molded product and the molded product 76 are integrated) is in the cavity 19 on the movable mold 71 side. Therefore, as shown in FIG. 16, the long molded product 3 that has been cooled and solidified can be taken out of the movable die 71 by projecting the molded product 76 by the two ejectors 10 provided on the movable die 71.

  At both ends in the longitudinal direction of the magnet piece 3 as a long molded product, there is a molded product 76 in which the molten resin material in the runner 18 and the resin reservoir 77 is cooled and solidified. The magnet piece 3 can be obtained by cutting (removing) using.

  By using such a long molded product mold 73, the ejector 10 does not come into contact with a long molded product as a product, so that the product does not leave a mark of the ejector 10.

  Further, in the case where the long molded product is a magnetic body having a magnetic force such as the magnet piece 3, the movable mold 71 and the fixed mold 72 are made of a non-magnetic rope, so that the magnet piece 3 is the movable mold 71 or the fixed mold. No 72. Therefore, the magnet piece 3 can be easily taken out without providing the ejector 10 in the cavity 19 on the movable mold 71 side.

  The above-described embodiments are illustrated for the purpose of explanation, and the present invention is not limited to these embodiments. The present invention can be recognized by those skilled in the art from the scope of the claims, the description, and the drawings. Modifications, deletions, and additions are possible as long as they are not contrary to the technical idea of the above.

  For example, in the above-described embodiment, the case where there are a total of two ejectors, one each for the runner and the resin reservoir portion, but one product each for the runner and the resin reservoir portion, and the product is molded. As long as there is no ejector in the cavity to be formed, the total number of ejectors may be three or more.

  Moreover, the protrusion part 78 shown in FIG.17 and FIG.20 may be attached to the fixed mold | type 91 side, as shown to the code | symbol 79 of FIG. Further, the protruding portion may not have a pin shape, and as described above, it may have a flat plate shape if it does not become an undercut.

  The present invention is applied to a magnet piece mold or the like used in an image forming apparatus.

DESCRIPTION OF SYMBOLS 10 Ejector 12 Parting line surface 13 Movable type | mold 14 Fixed type | mold 17 Orientation yoke 18 Runner 19 Movable type | mold side cavity surface 20 Fixed mold side cavity surface 21 Mold 23 for long molded products Molded product 26 Resin pool part 30 Cavity 38 Gauge G 78 Protruding part

Claims (6)

By combining a movable mold and a fixed mold, a long cavity, a runner communicated with one end in the longitudinal direction of the cavity via a gate, and a resin reservoir communicated with the other longitudinal end of the cavity are formed. In the mold for long molded products,
An ejector is provided on the runner on the movable mold side and the resin reservoir,
The molded product in which the molten resin in the runner and the resin reservoir is cooled and solidified is ejected by the ejector, whereby the long molded product in which the molten resin in the cavity on the movable mold side is cooled and solidified is taken out from the movable mold. Die for long molded products By combining a movable mold and a stationary mold made of a nonmagnetic material, a long cavity, a runner communicated with one end in the longitudinal direction of the cavity via a gate, and a resin communicated with the other longitudinal end of the cavity Forming a reservoir,
An orientation yoke for orientation-magnetizing magnetic powder of the molten resin in the cavity is disposed on the fixed mold,
In the mold for a long molded product in which the movable mold is provided with an ejector for taking out the long molded product cooled and solidified from the movable mold from the movable mold,
An ejector is provided on the runner on the movable mold side and the resin reservoir,
The molded product in which the molten resin in the runner and the resin reservoir is cooled and solidified is ejected by the ejector, and the long molded product in which the molten resin in the cavity is cooled and solidified is taken out from the movable mold. Mold for long molded products In the vicinity of the gate of the cavity on the movable mold side or the fixed mold side, a protrusion projecting into the cavity is provided,
The mold for a long molded product according to claim 1 or 2, wherein a cross-sectional area of the resin reservoir is gradually increased toward the other end in the longitudinal direction of the cavity. By combining a movable mold and a fixed mold, a long cavity, a runner communicated with one end in the longitudinal direction of the cavity via a gate, and a resin reservoir communicated with the other longitudinal end of the cavity are formed. Prepared long molded product mold,
Injecting molten resin from the runner of the long molded product mold to the cavity and the resin reservoir,
After the movable mold and the fixed mold are cooled and the molten resin is cooled and solidified, the movable mold is moved to open the mold,
The molded product in which the molten resin in the runner and the resin reservoir is cooled and solidified is ejected by an ejector provided in the movable mold, thereby taking out the long molded product in which the molten resin in the cavity is cooled and solidified from the movable mold. ,
A method for producing a long molded product, the method comprising cutting the molded product By combining a movable mold and a stationary mold made of a nonmagnetic material, a long cavity, a runner communicated with one end in the longitudinal direction of the cavity via a gate, and a resin communicated with the other longitudinal end of the cavity A reservoir is formed,
An orientation yoke that orients and magnetizes the magnetic powder of the molten resin in the cavity is disposed on the fixed mold,
Preparing a mold for a long molded product in which an ejector for taking out a long molded product in which the molten resin is cooled and solidified from the movable mold is disposed in the movable mold;
Injecting molten resin from the runner of the long molded product mold to the cavity and the resin reservoir while being oriented and magnetized by the orientation yoke,
After the movable mold and the fixed mold are cooled and the molten resin is cooled and solidified, the movable mold is moved to open the mold,
The molded product in which the molten resin in the runner and the resin reservoir is cooled and solidified is ejected by an ejector provided in the movable mold, thereby taking out the long molded product in which the molten resin in the cavity is cooled and solidified from the movable mold. ,
A method for producing a long molded product, the method comprising cutting the molded product The long molded product mold is further provided with a protruding portion protruding into the cavity in the vicinity of the gate in the cavity on the movable mold side or the fixed mold side,
The method for producing a long molded product according to claim 4 or 5, wherein the cross-sectional area of the resin reservoir is gradually increased toward the other end in the longitudinal direction of the cavity.

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