JP4644453B2 - Compression filling mold and magnet molding - Google Patents

Description

The present invention relates to a compression filling mold, a magnet molding, and a compression filling method that prevent deformation of a molded body when the molding material having a spring back is compression-filled into a long shape having an undercut. Used in image forming apparatuses such as copying machines, facsimile machines, printers, etc., and provided in a developing roller of a high-functional developing apparatus that develops a latent image formed on an image carrier using a two-component developer composed of toner and magnetic particles. it relates to the magnet molded body.

  In recent years, the “high-performance developing device that develops a latent image formed on an image carrier using a two-component developer composed of toner and magnetic particles” (SLIC developing device) has been attracting attention. In order to solve the image problem in the developing device, in the developing roller (magnet roller) mounted on the SLIC developing device, (A) the half width of the developing pole is 20 ° or less (conventional two-component development). And (B) the magnetic flux density is 120 to 140 mT (80 to 120 mT for the conventional two-component development). It is necessary to increase the density and to reduce the half width to half or less of the conventional one. The half width is an angular width of a portion indicating a half value of the maximum normal magnetic force (vertex) of the magnetic distribution curve in the normal direction of the developing main magnetic pole. If the maximum normal magnetic force is 120 mT, this is the angular width of the portion indicating a value of 60 mT.

  The present applicant satisfies a development condition for increasing the image density and a development condition for obtaining a low-contrast image at a high time, and a development method and a development apparatus for obtaining a high-quality image over the entire density range Japanese Patent Laid-Open No. 2000-305360 was previously proposed.

  However, in the developing device previously proposed by the applicant (hereinafter referred to as a slick developing device for the sake of convenience), the main pole portion of the developing roller has a narrower interpole angle than that of the conventional developing roller. A magnetic flux density equivalent to or higher and a narrow half-value width are required.

  Therefore, the present applicant has previously proposed Japanese Patent Application Laid-Open No. 2004-70045 as a developing roller manufacturing method that satisfies these requirements and can be used for a developing roller having a total length of about 300 mm.

In this developing roller, a groove-shaped storage portion is formed in a magnet roll formed by dispersing magnet powder in a polymer compound into a cylindrical shape, and a magnet corresponding to at least one development pole is embedded in the storage portion. As the magnet, an anisotropic rare earth magnet powder is made of a component different from the magnet powder as an additive, and the average particle size is smaller than the average particle size of the magnet powder, and dispersed, and It is formed by compression molding.
JP 2000-305360 A JP 2004-70045 A

  However, in a conventional long rectangular parallelepiped rare earth magnet block, as shown in FIG. 7, when the rare earth magnet block 51 after compression molding is taken out from the mold 50, it protrudes from the knockout plate 17 in a direction opposite to the compression direction. Although the rare earth magnet block 51 has been taken out, the compressed rare earth magnet block 51 becomes larger than the mold forming portion due to the spring back of the molding material, so that the end portion of the molded body is chipped and a chipped portion 51a is formed or curved. There is a problem that distortion such as the above occurs.

  In addition, when a shape having a concave or convex undercut, for example, an R shape (FIGS. 8A and 8B), is taken out of the mold, the mold is more than the convex part. It was necessary to open it and take out the rare earth magnet block.

Therefore, the present invention prevents the end of the molded body from being chipped or distorted when a molding material having a spring back when taken out from a die is compression-filled into a long shape having an undercut. It is an object of the present invention to provide a compression filling mold and a magnet molded body that can be used.

The invention according to claim 1 is divided into at least three or more dies of a pair of long side dies and a short side die, and a molding material having a spring back is faced at a predetermined interval between the pair of long dies. A compression filling mold for compressing and filling into a long shape having an undercut formed in the longitudinal direction of the long side die by one surface of a long surface forming transfer surface , wherein the compression filling die is A pair of long dies that are divided into at least three dies and can be opened in a short direction perpendicular to the long surface forming transfer surface, and between at least one end of the long dies and a short-side die provided, Ri movable der between the short ulnar die of the pair of long-side die longitudinally, at least one said short side die of the pair of long-side die One of the opposing surfaces has a convex part, and the other is engaged with the convex part And the convex portion and the concave portion are configured to be engaged by a slope that moves the long side die in the short direction when the short side die is moved in the mold opening direction. It is the compression filling metal mold | die characterized by the above-mentioned.

The invention of claim 2 is the compression filling mold of claim 1, wherein the molding material is a plastic magnet material obtained by mixing a magnetic powder and a polymer compound.

A third aspect of the present invention is the compression filling mold according to the first or second aspect, wherein the pair of long side dies are connected by an elastic body biased in the mold closing direction. .

The invention according to claim 4 is a magnet molded body formed by the compression filling mold according to claim 2 .

  According to the first aspect of the present invention, when the molding material having a spring back when being taken out from the die is compression-filled into a long shape having an undercut, the end of the molded body is chipped or distorted. Can be prevented.

Further, since the mold can be opened in the longitudinal direction and the lateral direction by mechanical control, the number of drive sources can be reduced.

According to the invention which concerns on Claim 2 or Claim 4 , the magnet molded object which can be used for the developing roller of a highly functional SLIC developing device can be obtained.

According to the invention of claim 3 , since it is not necessary to reassemble the mold that has been opened, the productivity of a molded body such as a magnet molded body is high, and the molded body can be manufactured at low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a view showing a developing roller according to an embodiment of the present invention, FIG. 2 is a view showing a rare earth magnet block compression filling device used in the developing roller of FIG. 1, and FIG. 3 is a compression attached to the compression filling device of FIG. FIG. 4 shows a filling mold, (A) is a plan view, (B) is a front view, (C) is a BB cross-sectional view in FIG. 3 (B), and FIG. 4 is a mold release of the compression filling apparatus of FIG. It is a figure which shows operation | movement, (A)-(C) is a cross-sectional view, (D) and (E) are longitudinal cross-sectional views.

  As shown in FIG. 1, the developing roller is provided with a cylindrical ferrite magnet 4 in a fixed state in the developing sleeve 2 that forms a magnetic field so as to cause developer spikes on its peripheral surface. The ferrite magnet 4 includes a main magnetic pole for causing the developer to rise in the development area, a conveyance pole for conveying the pumped developer to the development area, and a conveyance pole for conveying the developer in the developed area. And have. In the present embodiment, the main magnetic pole is formed by three rare earth magnet blocks 1 having opposite polarities, but the rare earth magnet block 1 may be one pole, or the developing pole may be composed of two poles or four poles or more. Good.

  The developing roller according to the present invention is a plastic magnet or a rubber magnet in which a ferrite magnet 4 is obtained by dispersing magnetic powder in a polymer compound, Sr ferrite or Ba ferrite is used as the magnetic powder, and 6PA or 12PA is used as the polymer compound. PA (polyamide) materials, ethylene compounds such as EEA (ethylene-ethyl copolymer) or EVA (ethylene-vinyl copolymer), chlorine-based materials such as CPE (chlorinated polyethylene), NBR (nitrile-butadiene) A rubber material such as rubber) can be used. The ferrite magnet 4 is provided with a storage groove 4a as a storage portion in which another member can be embedded in the portion corresponding to the developing pole of the cylindrical developing roller. The storage groove 4a has a higher magnetic force than the ferrite magnet 4. The rare earth magnet block 1 is housed and fixed. The surface of the rare earth magnet block 1 is coated with an adhesive or resin.

  The storage groove 4 a for attaching the rare earth magnet block 1 of the ferrite magnet 4 is processed with high accuracy in the straightness in the axial direction so that the rare earth magnet block 1 does not swell in the axial direction of the ferrite magnet 4. .

  In addition, the rare earth magnet block 1 in the developing pole portion is narrow and desirably uses a material of Br> 0.5T in order to obtain high magnetic properties, and most of them are Ne-based (Ne—Fe—B or the like) or Sm. Plastic magnets or rubber magnets in which rare earth magnets of the type (Sm—Co, Sm—Fe—N, etc.) or these magnet powders are mixed with a polymer compound similar to the above can be used. Furthermore, in the case of SLIC development, for example, a developing roller of φ16 to φ30 requires 80 to 90 mT as the magnetic flux density on the sleeve surface. The shape of the rare earth magnet block at the developing pole is 6 mm in width and 3 mm in height. It is necessary to fit in the size of the degree. In this case, it is desirable that Br> 0.5T as a material characteristic of the rare earth magnet block.

  As shown in FIG. 2, the rare earth magnet block compression filling device includes a filling device (not shown) for filling the mold filling portion with rare earth magnet powder, a compression filling die for forming the rare earth magnet block, and a compression. A mold fixing frame for fixing the filling mold, a compression apparatus for compressing the rare earth magnet powder in the mold filling portion, and a demolding apparatus for taking out the compressed rare earth magnet block are provided.

  As the filling device (not shown), a known powder filling device for a compression filling device is used. The body filling portion 15 is filled with the rare earth magnet powder described above. The rare earth magnet powder may be filled into the powder filling portion 15 of the compression filling mold 10 after the compression filling mold 10 is fixed to the mold fixing frame 7.

  As shown in FIG. 3A, the compression filling mold 10 includes a first long side die 11, a second long side die 12, a first short side die 13, and a second short length. A side die 14 is provided.

  The first long die 11 is a movable mold having a long convex shape in plan view and movable in the short direction, and is a mold filling portion as shown in FIG. An R-shaped transfer surface 11 c is formed below the powder filling unit 15.

  The second long die 12 has a long convex shape in plan view, and the first long die 11 and the long surface forming transfer surface at the tip of the convex shape face each other at a predetermined interval. In this state, the powder filling portion 15 is formed and is a fixed mold.

  In the present embodiment, both the first short side die 13 and the second short side die 14 have a convex shape in plan view, and the tip portions thereof are the first long side die 11 and the second long side die. It is slidably sandwiched between both ends of the die 12.

  The first long die 11, the second long die 12, and the first short die 13 are in pressure contact with each other by the urging force of a tension spring 16 that is an elastic body. Similarly, the first long side die 11, the second long side die 12, and the second short side die 14 are pressed against each other by the biasing force of the tension spring 16. As the elastic body, in addition to the tension spring 16, a leaf spring, rubber, or the like may be used.

  The first short side die 13 and the second short side die 14 include a tension spring 16 when the short side die 13 and the second short side die 14 move in the longitudinal direction (long direction of the mold), respectively. The long holes 13b and 14b are formed.

  Further, as shown in FIG. 4A, the first long side die 11 has a concave portion 11a formed on the surface facing the first short side die 13, and the outer side end in the mold longitudinal direction of the concave portion 11a. Has a slope. The first short-side die 13 has a convex portion 13a on the surface facing the first long-side die 11, and a first long side is formed at the outer end in the mold longitudinal direction of the convex portion 13a. A slope having the same inclination as the slope of the concave portion 11a of the scale die 11 is formed.

  Similarly, the first long-side die 11 has a recess 11a formed on the surface facing the second short-side die 14, and a slope is formed at the outer end of the recess 11a in the mold longitudinal direction. The second short-side die 14 has a convex portion 14a on the surface facing the first long-side die 11, and the first long side of the convex portion 14a is located at the outer end in the mold longitudinal direction. A slope having the same inclination as the slope of the concave portion 11a of the scale die 11 is formed.

  The mold fixing frame 7 fixes the compression filling mold 10 and supports the press 8. Further, in this embodiment, air core coils 21 and 22 are arranged around the fixed compression filling mold 10. To do. The air-core coils 21 and 22 can make a magnetic field act on a molded object as needed at the time of compression molding.

  The compression device is constituted by a press machine 8 and moves the punch 9 facing the powder filling portion 15 of the compression filling mold 10 forward and backward toward the powder filling portion 15.

  As shown in FIG. 4D, the demolding apparatus includes a cylinder 18 that moves the first short-side die 13 and the second short-side die 14 in the longitudinal direction of the mold, and a direction opposite to the compression direction. A knockout plate 17 and a cylinder 19 for extruding the molded body are provided.

  The operation of the compression filling apparatus configured as described above will be described next. First, as shown in FIG. 2, the compression filling mold 10 in which a predetermined amount of rare earth magnet powder is supplied to the powder filling section 15 is fixed to the mold fixing frame 7.

  Next, the press machine 8 is actuated to push the punch 9 into the powder filling portion 15 and compress the rare earth magnet powder to compress the rare earth magnet block 1.

  Next, the mold 10 after compression molding is taken out from the mold fixing frame 7 and set in a demolding apparatus shown in FIG. FIG. 4A shows a molded state.

  Next, as shown in FIG. 4B, a cylinder 18 is formed so that the first short side die 13 and the second short side die 14 at both ends in the longitudinal direction of the post-compression mold 10 are opened outward. Move a little at. At this time, the spring back in the longitudinal direction of the rare earth magnet block 1 is released, and the compact is slightly expanded in the longitudinal direction.

  Next, as shown in FIG. 4C, a cylinder 18 is opened so that the first short side die 13 and the second short side die 14 at both ends in the longitudinal direction of the post-compression mold 10 are opened outward. Move further with. Thereby, the slope of the convex portion 13a of the first short-side die 13 and the slope of one concave portion 11a of the first long-side die 11 slide and slide along the slope, and the second The slope of the convex portion 14a of the short side die 14 and the slope of the other concave portion 11a of the first long side die 11 slide and slide along the slope. In this way, the first long die 11 on the movable side moves in the short direction of the mold 10 after compression molding against the spring force of the tension spring 16 and opens. At this time, the spring back in the short direction of the rare earth magnet block 1 is released, and the molded body slightly expands in the short direction.

  Next, as shown in FIG. 4D, the cylinder 19 is operated to move the knockout plate 17 upward. Further, as shown in FIG. 4E, the cylinder 17 is operated to take out the rare earth magnet block 1.

  As described above, the springback is released and the rare earth magnet block 1 is taken out of the die 10 after compression molding, so that distortion such as warping, chipping, or the like does not occur. Therefore, Ne-type (Ne-Fe-B, etc.) or Sm-type (Sm-Co, Sm-Fe-N, etc.) rare earth magnets having a spring back after molding or these magnet powders are mixed with the above-described polymer compound. When molding materials such as plastic magnets or rubber magnets into a long shape having an undercut such as an R shape, it is possible to prevent the end of the molded body from being chipped or distorted. . A high-magnetic force and high-precision developing roller required for the SLIC developing device of the ferrite magnet 4 can be obtained from the rare earth magnet 1 thus formed.

  Further, in the above embodiment, the first short side die 11, the convex portion 13 a of the first short side die 13, and the convex portion 14 a of the second short side die 14 make the first short length. By simply driving the side die 13 and the second short side die 14 to the outside, the first long side die 11 can be moved to the outside at a predetermined timing in conjunction with this. In 18, the mold opening in the longitudinal direction and the mold opening in the short direction can be performed in conjunction with each other. And the said timing adjusts the space | interval (gap) between the recessed part 11a of the 1st long side die | dye 11, the convex part 13a of the 1st short side die 13, and the convex part 14a of the 2nd short side die 14. This can be set arbitrarily.

  FIG. 5 is a view showing a mold release operation according to a modification of the compression filling mold of FIG. This modification is an example in which 14 is omitted and the mold is divided into three, and the operation similar to that in FIG. 4 can be performed only by driving the first short-side die 13 in this way.

  FIG. 6 is a view showing a main part of a modification of the compression filling mold of FIG. 4 or FIG. In this modification, in the compression filling mold 10 of FIG. 4 or 5, the first long side die 11 is provided with a concave portion 11 a and the first short side die 13 and the second short side die 14 are convex. In contrast to the provision of 13a and 14a, as shown in FIG. 6, the concave-convex relationship is reversed, the first long die 11 is provided with a convex portion 11b, and the first short side die 13 is provided with a concave portion 13c. Is an example. Although the illustration of the second short-side die 14 is omitted, the concave-convex relationship can be similarly changed. In addition, this invention is not limited to the said Example. That is, various modifications can be made without departing from the scope of the present invention.

It is a figure which shows the developing roller of one Embodiment which concerns on this invention. It is a figure which shows the compression filling apparatus of the rare earth magnet block used for the developing roller of FIG. The compression filling metal mold | die attached to the compression filling apparatus of FIG. 2 is shown, (A) is a top view, (B) is a front view, (C) is BB sectional drawing in FIG. 3 (B) figure. It is a figure which shows mold release operation | movement of the compression filling apparatus of FIG. 2, (A)-(C) is a cross-sectional view, (D) and (E) are longitudinal cross-sectional views. It is a figure which shows the mold release operation | movement by the modification of the compression filling metal mold | die of FIG. It is a figure which shows the principal part of the modification of the compression filling metal mold | die of FIG. 4 or FIG. It is a figure for demonstrating the subject of the conventional compression filling metal mold | die. (A) is a sectional view of a compression filling mold, and (B) is a view showing a developing roller in which an R-shaped rare earth magnet block is embedded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rare earth magnet block 1a R shape 2 Sleeve 3 Adhesive 4 Ferrite magnet 4a Housing groove 5 Core metal with a reference surface 6 Magnetic flux density distribution 7 Mold fixing frame 8 Press machine 9 Punch 10 Compression filling mold 11 1st long side Die 11a Concave part 11b Convex part 11c Transfer surface 12 Second long side die 13 First short side die 13a Convex part 13b Long hole 13c Concave part 14 Second short side die 14b Long hole 15 Powder filling part 15a R shape 16 Tension spring (elastic body)
17 Knockout plate 18 Cylinder 19 Cylinder 21 Upper air core coil 22 Lower air core coil

Claims (4)

One of the long surface forming transfer surfaces which is divided into at least three or more dies, a pair of long dies and a short dies, and which has a spring back and faces each other at a predetermined interval between the pair of long dies. A compression filling mold for compression filling molding into a long shape having an undercut formed in the longitudinal direction of the long side die by the surface of the long side die , wherein the compression filling mold is divided into at least three or more dies. A pair of long side dies that can be opened in the short direction perpendicular to the long surface forming transfer surface, and a short side die provided between at least one end of the long side die. and, Ri movable der between the short ulnar die of the pair of long-side die longitudinally,
At least one of the pair of long-side dies and one of the opposed surfaces of the short-side die has a convex portion, and the other has a concave portion that engages with the convex portion, and the convex portion and the concave portion Are configured to engage with a slope that moves the long die in the short direction when the short die is moved in the mold opening direction . 2. The compression filling mold according to claim 1 , wherein the molding material is a plastic magnet material in which magnetic powder and a polymer compound are mixed. The compression filling mold according to claim 1 or 2 , wherein the pair of long side dies are connected by an elastic body biasing in a mold closing direction. A magnet molded body molded by the compression filling mold according to claim 2 .

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