WO2003011558A1 - Procede destine au moulage d'un aimant plastique, et culasse de magnetisation utilisee a cet effet, et procede destine a la realisation d'un cylindre magnetique - Google Patents

Procede destine au moulage d'un aimant plastique, et culasse de magnetisation utilisee a cet effet, et procede destine a la realisation d'un cylindre magnetique Download PDF

Info

Publication number
WO2003011558A1
WO2003011558A1 PCT/JP2002/007073 JP0207073W WO03011558A1 WO 2003011558 A1 WO2003011558 A1 WO 2003011558A1 JP 0207073 W JP0207073 W JP 0207073W WO 03011558 A1 WO03011558 A1 WO 03011558A1
Authority
WO
WIPO (PCT)
Prior art keywords
magnet
magnetic
magnetic force
magnet roller
magnetic field
Prior art date
Application number
PCT/JP2002/007073
Other languages
English (en)
Japanese (ja)
Inventor
Yuichi Hamaguchi
Taihei Goto
Original Assignee
Bridgestone Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2001387371A external-priority patent/JP2003188011A/ja
Application filed by Bridgestone Corporation filed Critical Bridgestone Corporation
Publication of WO2003011558A1 publication Critical patent/WO2003011558A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0253—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets for manufacturing permanent magnets
    • H01F41/0273—Imparting anisotropy
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/0013—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor using fillers dispersed in the moulding material, e.g. metal particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
    • G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/17—Component parts, details or accessories; Auxiliary operations
    • B29C45/1701—Component parts, details or accessories; Auxiliary operations using a particular environment during moulding, e.g. moisture-free or dust-free
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
    • B29K2105/20—Inserts
    • B29K2105/203—Magnetic parts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0003—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular electrical or magnetic properties, e.g. piezoelectric
    • B29K2995/0008—Magnetic or paramagnetic

Definitions

  • the present invention relates to a method of forming a magnet piece or other plastic magnet having a substantially fan-shaped cross section as a component of a magnet roller used as a developing roll of a copying machine or a printer, and a magnetizing method used for the same. And a method of manufacturing a magnet roller.
  • Electrophotographic devices such as copiers and printers ⁇
  • a magnet formed by a resin magnet inside a rotating sleeve is used as a development method to visualize an electrostatic latent image on a latent image holder such as a photosensitive drum.
  • a roller is provided, and the toner carried on the surface of the sleeve flies onto the latent image carrier by the magnetic characteristics of the magnet roller.
  • the toner is supplied to the surface of the latent image carrier by a jamming phenomenon, and an electrostatic latent image is formed.
  • Development methods for visualizing are known.
  • a resin material in which magnetic powder such as ferrite is mixed and dispersed in a binder of thermoplastic resin such as nylon or polypropylene is injected into the magnetic field of the mold cavity to have a fan-shaped cross section.
  • a method of manufacturing the magnet piece by adjoining the magnet pieces to each other in a circumferential direction around a shaft and combining them in a cylindrical shape is widely used.
  • FIG. 12 is a schematic cross-sectional view showing a magnet roller 90 formed in this manner.
  • This magnet roller 90 is composed of magnet pieces 92 and 94 having an N pole and a magnet having an S pole. It is formed by arranging the pieces 91, 93 circumferentially adjacent to each other around the shaft 95. Magnet opening formed in this way Has the following two problems.
  • the first problem is that when a circumferential magnetic force pattern of a magnet roller is given, this magnetic force pattern was conventionally realized by optimizing the cross-sectional shape of each magnet piece. It takes a long time for trial production and a lot of know-how to obtain the final shape, and in some cases, the required magnetic performance may not be sufficiently satisfied no matter how many trials are performed.
  • a magnetized yoke 85 is formed at a position corresponding to, for example, a substantially central portion of an arcuate surface 84 formed on the upper die 81 and defining the molded cavity 83, while defining the sector-shaped molded cavity 83.
  • the magnetic powder was mixed and dispersed in the molding cavity 83 formed with a magnetic field by the magnetizing yoke 85 when the tip end surface of the narrow protrusion was fixedly arranged on the upper die 81 close to the arcuate surface 84.
  • the required magnetic characteristics for the magnet roller 90 are as follows. For example, if the N pole is located on one side from the circumferential center of the outer peripheral surface of the magnet piece 92, the magnetizing yoke 8 By displacing 5 from the center of the arcuate surface 84 to one side, the magnetic pole position of the N pole can be formed accurately, but in this case, the circumferential magnetic force pattern there is Because of the large spacing, the shoulders Sh as shown in Fig. 14 are obtained, and the circumferential magnetic force pattern must be corrected or changed to a smooth pattern as shown in Fig. 15. Is required.
  • the magnet pieces 91 to 94 are formed by injection molding. Although the problem in the case of forming the magnet pieces has been described, there is a similar problem in the case where the magnet pieces 91 to 94 are extruded.
  • a resin material containing magnetic powder is extruded into a die opening where a magnetic field is formed by a magnetized yoke, and then cut into a predetermined length to form a magnet piece.
  • the cross-sectional view of the die and the die opening is similar to the cross-sectional view shown in FIG. 13, and the magnetizing yoke is located at a position corresponding to, for example, substantially the center of the arc-shaped surface that defines the die opening.
  • the magnetic powder By extruding the magnet piece, the magnetic powder can be concentrated and oriented at the portion of the magnet piece close to the magnetized yoke, and the magnetic pole can be formed there. Due to the location and shape, the circumferential magnetic pattern has a shoulder Sh, as in the case where it is formed by injection molding, and there is a problem that this magnetic pattern must be corrected. .
  • the circumferential magnetic force pattern is confirmed by cutting the side face of the sector-shaped magnet piece 92 and changing the sector shape, etc. While the final shape of the magnet piece 92 is specified, a molding die or an extrusion die is manufactured based on the final shape. The same applies to other magnet pieces. Conventionally, the final shapes of the magnet pieces 91 to 94 are specified through such a complicated process, and this leads to the first problem described above.
  • the second problem is that the magnet roller 90 made by combining the magnet pieces 91 to 94 does not have a uniform magnetic force distribution in the roller axis direction.
  • the process of measuring and grinding the magnetic force was required, and this required extra man-hours and capital investment.
  • the magnet roller 90 which is simply a combination of the magnet pieces 91 to 94, can obtain the desired circumferential magnetic force pattern at the axial center portion, but at the axial end portions.
  • the magnetic force is higher than the central part in the axial direction, a so-called shoulder-raising phenomenon occurs. Therefore, when such a magnet roller is used in a copying machine or the like, the expected performance at the axial end is obtained. Therefore, there is a problem that the image corresponding to the axial end portion becomes darker or lighter than the image corresponding to the central portion.
  • Fig. 16 is a graph illustrating the magnetic force distribution in the axial direction of the N pole of the magnet roller 90 of the magnet roller 90, where the horizontal axis represents the axial position and the vertical axis represents the axial position.
  • Pc indicates a point at the center of the magnet roller 90 in the axial direction
  • P1 and P2 indicate the axial ends of an effective portion where the magnetic force of the magnet roller is to function.
  • shoulder-up phenomenon occurs.
  • the axial end of the magnet roller 90 is formed in a predetermined procedure or according to the result of measuring the magnetic force.
  • the magnetic force must be adjusted by grinding a predetermined portion, which is the second problem described above.
  • the object of the present invention is to solve the first problem by forming a required circumferential magnetic force pattern, By changing the shape or structure of the magnetized yoke without changing the shape of the plastic magnet such as the magnet piece, it is possible to modify or change the circumferential magnetic force pattern compared to the conventional technology. It can be done in a short time without the need for know-how In order to provide a method for molding a plastic magnet and a magnetized yoke used for the same, which enable usual injection molding of the magnet,
  • the magnetic force at the axial end of the magnet roller formed by combining the magnet pieces in the circumferential direction can be formed substantially equal to the magnetic force at the axial center. Further, it is an object of the present invention to provide a method of manufacturing a magnet roller which does not require adjusting the magnetic force by forming a cylindrical magnet roller and then grinding the same.
  • the present invention has been made, and its gist configuration and operation will be described below.
  • the method for molding a plastic magnet of the present invention includes the steps of: injecting a resin material containing magnetic powder into a molding cavity in which a magnetic field is formed by a magnetized yoke; When extruding a resin material containing magnetic powder and molding a plastic magnet,
  • a strong magnetic field is formed at the molding cavity or die opening at the portion of the magnetized yoke closest to the molding cavity or die opening, and the magnetic field is formed at a predetermined region on at least one side of the region where the strong magnetic field is formed. It creates a relatively weak magnetic field in the cavity or die opening.
  • This molding method was made in response to the first problem described above.
  • a molten resin mixed with magnetic powder was injected into a molding cavity, or a magnetic field was formed by a magnetized yoke.
  • a magnetic pole can be formed in a plastic magnet formed by extruding a resin material containing magnetic powder into a die opening, by intensively orienting the magnetic powder in a portion having a strong magnetic field.
  • a shoulder Sh may be generated in the circumferential magnetic force pattern as illustrated in FIG. 14, and according to the method of the present invention, at least one side of a region where a strong magnetic field is formed.
  • a relatively weak magnetic field is formed in the molding cavity or in the die opening in the predetermined region of the mold, for example, in the region corresponding to the above-mentioned shoulder Sh, and the magnetic powder is slightly oriented in the weak magnetic field. Is performed, the shoulder Sh ′ in the circumferential magnetic force pattern as shown in FIG. 14 is substantially eliminated, and a smooth circumferential magnetic force pattern as shown in FIG. 15 is obtained. Can be.
  • the expected circumferential magnetic force pattern can be obtained without specifying the final shape of the plastic magnet, which involves a change in shape, etc., and manufacturing a molding die or die based on the final shape. It can be easily realized in a short time.
  • the magnetized yoke according to the present invention which is preferably used for carrying out the above method, is made of a magnetic material, and is disposed in close proximity to a molding cavity of a plastic magnet or a die opening.
  • a magnetic field is formed in the die opening, and at least one side of the molding cavity or the narrow projection located closest to the die opening in the cross section in the width direction of the magnetization yoke.
  • a retreating part is provided which tends to be separated from the molding cavity.
  • the term “prone” refers to the molding cavity or the shape of the die opening, the shape of the receding portion, etc., and the retracted portion partially approaches the molding cavity while moving away from the narrow projection. Such cases are also intended to be included in the above invention.
  • a strong magnetic field can be formed in the molding cavity or the die opening with a narrow protrusion, and a relatively weak magnetic field can be formed by the receding portion. It can be used in the implementation of the method described above to provide the same effects as described above.
  • the recessed portion provided on the narrow projection has a relationship between the required magnetic characteristics and the original magnetic characteristics without the recessed portion, as described in FIG. It can be used to eliminate the shoulder Sh as shown in the figure, or to artificially increase the magnetic force in the part where the shoulder is not originally formed. It can be done only on the side or on both sides.
  • the recessed portion is an inclined surface or one or a plurality of step-shaped recessed portions.
  • the magnetic field formed in the molding cavity or the die opening can be gradually weakened as the distance from the narrow projection increases. Also, when it is made into a step shape, it can be gradually reduced.
  • a plurality of rod-shaped magnet pieces made of a resin material in which a magnetic powder is mixed and dispersed in a resin binder are formed in a columnar shape on the outer periphery of the shaft, adjacent to each other in the circumferential direction.
  • the magnet pieces After magnetizing at least one of the magnet pieces so that the magnetic force at both ends in the axial direction is lower than the magnetic force at the central portion in the axial direction at least in a part in the circumferential direction, the magnet pieces are removed from the remaining magnet pieces. It is formed in combination with a piece.
  • a method of manufacturing a magnet roller according to the present invention has been made in response to the first problem described above.
  • the inventors In order to investigate the cause of the magnetic force rising at the end of the conventional magnet roller, the inventors have determined the axial magnetic force distribution of the magnet piece alone and the magnetic force of this magnet piece after being combined with the magnet roller. The distributions were compared. As a result, in the magnetic force distribution of the magnet piece alone, However, with the magnet roller after the magnet pieces were combined, it was found that the magnetic force at the end of this portion was even greater and the shoulder was raised.
  • the manufacturing method of the magnet roller according to the present invention is based on this newly obtained knowledge, and according to this manufacturing method, the magnetic force generated by ascending the end shoulder when combining the magnet pieces is generated.
  • the magnet piece is formed by lowering the magnetic force at the end in the axial direction compared to the central part in the axial direction by the amount of the increase, so when the magnet pieces are combined with each other,
  • the magnetic force at the axial end of the roll is almost equal to the magnetic force at the center of the roll, and a magnet roller having a uniform magnetic force distribution in the axial direction can be formed.
  • a step of grinding the magnet roller after forming the magnet roller is not required, and the magnet roller can be manufactured simply and at low cost.
  • the method of manufacturing a magnet roller according to the present invention wherein in the invention described in (4), among the plurality of magnetic poles, at least one pair of repulsive poles which are adjacent to each other and have the same polarity is provided.
  • a magnetic roller used in a copying machine or the like at least one set of repulsive poles adjacent to each other is disposed among a plurality of magnetic poles disposed on the periphery of the magnet roller in order to improve a toner recovery rate.
  • a magnet roller having a zero gauss band with almost zero magnetic force and a flat magnetic force distribution in the circumferential direction is used.
  • such a zero Gaussian band has a small strength of its own magnetic field, and is affected by repulsion poles located on both sides in the circumferential direction, and its magnetic force distribution tends to be unstable.
  • the magnetic force at the axial end is affected by the discontinuity at the end As a result, it became more unstable, and it was more difficult to suppress the phenomenon of magnetic force rising at the end than in normal magnetic poles.
  • the magnet pieces including the zero Gauss band are magnetized so that the magnetic force at both ends in the axial direction of the magnet piece combined adjacently between the repulsion poles is lower than the magnetic force at the central portion in the axial direction.
  • the magnetic force in the axial direction can be made uniform by the shoulder magnetic force of the end portion, so that a particularly advantageous effect can be brought about.
  • a magnetizing yoke for magnetizing the inner peripheral surface to the polarity opposite to the repulsion pole is arranged at a position facing the inner peripheral surface side of the magnet piece, and these magnets are placed at opposing positions on both the side surfaces.
  • the method of manufacturing this magnet roller relates to a zero gauss band, in which it is particularly difficult to form a magnetic force.
  • a magnetic pole having a polarity opposite to that of the repulsion pole is formed on the inner peripheral surface of the shaft. After forming a magnetic pole having the same polarity as the repelling pole on the side, the magnet piece is demagnetized, and then the inner circumferential surface of the magnet piece is opposite in polarity to the repelling pole at the opposing position on the inner circumferential surface side of the magnet piece.
  • a magnetizing yoke that magnetizes these magnets is arranged, and magnetizing yokes that magnetize these sides to the same polarity as the repulsion poles are arranged at opposite positions on both sides of the magnet. From both sides to the inner circumference By thus forming a strongly oriented magnet, the number of lines of magnetic force directed outward from the outer peripheral surface of the magnet piece can be suppressed, and the magnetic force in the zero gauss band can be reduced to almost zero.
  • the magnet roller after the magnet piece is demagnetized, in addition to the above-described magnetized yokes arranged on the inner circumferential surface and both side surfaces of the magnet piece, the opposing positions of the axially opposite end portions on the outer circumferential surface side are further reduced.
  • a magnetizing yoke that applies a magnetic force of the opposite polarity to the zero Gaussian band is also arranged at both ends of the magnet piece so that the magnetic force at both ends in the axial direction of this magnet piece is lower than the magnetic force at the central part in the axial direction. Since it is magnetized, as described above, after it is combined with a cylindrical magnet roller, a magnet roller having a uniform magnetic distribution in the axial direction in the zero Gauss band can be formed.
  • the method of manufacturing a magnet roller according to the present invention is characterized in that, in the invention described in (6), the magnetized shock arranged at a position opposite to both axial ends on the outer peripheral surface side of the magnet piece is positioned from a central portion in the axial direction. It is arranged to be inclined so that it gets closer to the peripheral surface of the magnet piece as it goes away.
  • the magnetized yoke which is disposed at a position opposed to both ends in the axial direction on the outer peripheral surface side of the magnet piece, is moved closer to the peripheral surface of the magnet piece as the distance from the axial center increases. Since the magnet pieces are arranged at an inclination, a magnetic force distribution in which the magnetic force decreases smoothly from the center in the axial direction toward the end can be formed in the zero gauss band of the magnet piece. Since it works to cancel the edge rise when it is combined with the magnet roller, it works to cancel the edges, so the zero Gaussian band with uniform magnetic force distribution from the axial center to the end in the state after the magnet piece is combined It is possible to form a magnet roller having the following.
  • FIG. 1 is a longitudinal sectional view showing an application example of a magnetized yoke.
  • FIG. 2 is a cross-sectional view of a main part illustrating a mold apparatus used for injection molding.
  • FIG. 3 is a longitudinal sectional view showing another embodiment of the magnetization yoke.
  • FIG. 4 is a diagram showing a modified example of the retreat portion.
  • FIG. 5 is a schematic sectional view showing a magnet roller.
  • FIG. 6 is a magnetic force pattern diagram of the magnet roller.
  • FIG. 7 is a graph showing the magnetic force distribution of the magnet piece in the zero Gauss band.
  • FIG. 8 is a graph showing the magnetic force distribution of the magnet roller in the zero Gauss band.
  • FIG. 9 is a cross-sectional view showing the magnetization orientation of the magnet piece.
  • FIG. 10 is a side view showing the arrangement of the magnetization yoke.
  • FIG. 11 is a sectional view taken along the line XI-XI of FIG.
  • FIG. 12 is a sectional view of a magnet roller manufactured by a conventional method.
  • FIG. 13 is a longitudinal sectional view of a molding die using a conventional magnetized yoke.
  • FIG. 14 is a diagram illustrating a circumferential magnetic force pattern of a conventional magnet roller.
  • FIG. 15 is a diagram illustrating a circumferential magnetic force pattern after correction.
  • Figure 16 is a graph showing the magnetic force distribution of the N pole of a magnet roller manufactured by a conventional method.
  • Fig. 17 is a graph showing the magnetic force distribution in the zero gauss band of a magnet piece magnetized by a conventional method.
  • FIG. 1 is a longitudinal sectional view of a molding die showing an application example of a magnetized yoke according to the present invention.
  • 1 shows an upper die
  • 2 shows a lower die
  • 3 shows a shape between the upper and lower dies. It shows a molded cavity that has a substantially sectorial cross-section.
  • the magnetized yoke 4 is fixedly arranged on the upper mold 1, and the distal end face of the narrow projection 5 of the magnetized yoke 4 corresponds to the center of the upper mold arc surface 6 that defines the molding cavity 3.
  • the magnetized yoke 4 is provided with an inclined surface-like recessed portion 7 that is gradually separated from the molding cavity 3 as the angle increases.
  • such a magnetized yoke 4 is surrounded by a non-magnetic material 8, and the upper surface thereof is backed up by a magnetic material 9 and attached to the upper mold 1, and the molding cavity 3 is also formed.
  • the recessed portion 10 of the lower mold 2 to be partitioned is formed in the magnetic material 11.
  • the above-described molding die 12 is made into a mold device 13 as a set of four parts, and is subjected to injection molding.
  • the magnetized yoke 4 of each mold 12 forms a magnetic field in the molding cavity 3 based on the energization of the magnetized coil 14 disposed around the device 13, and is not shown.
  • the molten resin material containing the magnetic powder injected from the injection nozzle is pressure-filled into the molding cavity 3 from a sprue 15 through a runner 16 and a gate (not shown).
  • the resin material filled in the molding cavity 3 in this manner has a strong magnetic field in a region corresponding to the high-density magnetized yoke 4 and the narrow projections 5 as indicated by broken lines in FIG. From this, the magnetic powder is concentrated and oriented in that region, and a magnetic pole is provided there. On the other hand, in the region 17 corresponding to the receding portion 7, some orientation of the magnetic powder is performed based on the fact that the resin material is affected by the relatively weak magnetic field. Due to these facts, when a conventional magnetized yoke 85 without the retreat portion 7 is used, a circumferential magnetic force pattern with a shoulder Sh is obtained as shown in FIG. In the magnetized yoke 4 according to the present invention provided with 7, the circumferential magnetic force pattern as shown in FIG. 15 can be easily realized.
  • a recessed portion similar to or different in shape from the previous case may be provided on the right side of the narrow protrusion 5. According to this, the magnetic force on the opposite side of the peak in the circumferential magnetic force pattern is Can be increased.
  • FIG. 3 is a cross-sectional view showing another form of the magnetized yoke.
  • the magnetized yoke is formed so as to be biased to one side of the magnet piece to be formed, that is, to the right side in the figure, and to have a circumferential magnetic force.
  • a recessed portion 7 with an inclined surface that is wider than in the previous case is provided on the left side of the narrow protrusion 5. .
  • the intended purpose can be achieved by forming a weak magnetic field in the corresponding region 17 under the action of the receding portion 7 to bring the orientation of the magnetic powder there.
  • FIG. 4 is a diagram showing a modified example of the retreating portion of the magnetized yoke
  • FIG. 4a is a diagram in which the retreating portion 7 is formed into an inclined surface directly continuing to the distal end surface of the narrow projection 5. 1 and 3, this corresponds to a case where the step-down portion in the direction away from the molding cavity 3 is omitted.
  • FIG. 4B shows the retreating portion 7 in the form of a single horizontal plane stepping down from the distal end surface of the narrow projection 5.
  • the strength of the magnetic field formed in the receding portion 7 can be selected as required.
  • FIG. 5 is a schematic cross-sectional view showing a cross section of the magnet roller 21 according to the present invention.
  • the magnet roller 21 is formed by combining six rod-shaped magnet pieces 31 to 36 adjacent to each other in the circumferential direction around the shaft 22. These magnet pieces 31 to 36 are respectively , Which have N 1 to N 3 poles, S 1 pole, S 2 pole magnetic poles, and zero Gaussian band NO. here,
  • the N1 to N3 poles are magnetic poles having the polarity of N
  • the S1 to S2 poles are magnetic poles having the polarity of S. Of these, N2 and N3 are repulsive poles forming a pair.
  • FIG. 6 is a graph showing a circumferential magnetic force pattern obtained by measuring the magnetic force on the circumferential surface of the magnet roller 21.
  • the horizontal axis represents the circumferential position by an angle, and the vertical axis represents the magnitude of the magnetic force.
  • the magnet roller 21 has a zero Gaussian band between the pair of repulsive poles N 2 and N 3 having a magnetic force distribution of N and a magnetic force distribution which spreads flat in the circumferential direction while the magnetic force is almost zero. .
  • FIG. 7 is a graph showing the magnetic distribution in the axial direction of the zero Gaussian band N 0 in the magnet piece 36 before being combined with the magnetic roller 21.
  • the horizontal axis represents the axial position, and the vertical axis represents the magnetic force. Indicates the size.
  • the range of P1 to P2 is the effective range of the magnetic force when the magnet roller 1 is mounted on the apparatus. In the method of manufacturing the magnet roller, when magnetizing the magnet piece 36, P1 and P2 are used.
  • the magnetic force at the axial position near the end near 2 is formed to be smaller than the magnetic force at the center in the axial direction, and the magnetic force becomes smaller toward the end.
  • FIG 8 is a graph showing the axial magnetic force distribution of the zero Gaussian band NO after forming the magnet roller 21 by combining the magnet piece 36 with the other magnet pieces 31 to 35.
  • the magnetometer shows that it is possible to distribute the magnetic force in the zero Gaussian band NO uniformly in the axial direction and to control the magnetic force to be almost zero. ing.
  • the magnetic force at the end of the magnet piece 36 before being combined with the magnet roller 21 in the zero-gauss band is smaller than that in the center. It is important to keep this in mind, and this can be achieved by the following method.
  • FIG. 6 is a cross-sectional view showing the orientation of the magnetic powder in the cross section of FIG. 6, wherein the orientation of the magnetic powder is such that the inner peripheral surface 41 side of the magnet piece 36 is an S pole, and both side surfaces 42 are N poles.
  • an AC magnetic field is applied to the magnet piece 36 to demagnetize it once, and a magnetizing yoke is arranged around the magnet piece 36 to magnetize the piece 36.
  • FIG. 10 is a side view showing the arrangement of the magnetized yokes
  • FIG. 11 is a cross-sectional view showing a XI-XI cross section of FIG.
  • a magnetized yoke 51 of polarity N is arranged facing the inner peripheral surface 41 of the magnet piece 36, and a magnetized yoke 52 of polarity S is arranged facing both sides 22.
  • the inner peripheral surface 41 is magnetized to the S pole, and both side surfaces 42 are magnetized to the N pole.
  • the magnetizing yokes 53 with N polarity on both ends of the outer peripheral surface 43 of the magnet piece 36, the end of the cellogauss band NO originally oriented slightly toward the N pole Demagnetize the magnetic force. Further, the magnetizing yoke 53 is gradually inclined from the axial center to the end of the magnet piece 36 so as to approach the outer peripheral surface 43 of the magnet piece 36. A nonmagnetic spacer 54 having a triangular cross section is provided between the outer peripheral surface 43 of the magnet piece 36 and the magnetized yoke 53.
  • the magnetic force distribution at the axial end is lower than the magnetic force at the center as shown in Fig. 3.
  • the magnet piece 36 having the zero Gaussian band NO can be formed.
  • the magnet piece 36 will have an axial magnetic force distribution as shown in FIG.
  • the magnetic force at the end in the axial direction is further emphasized and the shoulder rises, which is an improvement over what could not be used for practical use.
  • the magnet piece 36 molded in a magnetic field was temporarily erased. After magnetizing, re-magnetization was performed. Even if re-magnetization is performed without degaussing, the same effect can be obtained depending on the magnetizing conditions. Further, in this embodiment, the magnet piece 36 having a zero Gaussian band has been described. However, apart from the magnitude of the effect, these are incorporated into the magnet roller for other magnet pieces 31 to 35 as well. By reducing the magnetic force at the axial end portion from the magnetic force at the central portion in the previous state, the axial magnetic force distribution after combination with the magnet roller can be made more uniform.
  • the resin material mixed with the magnetic powder is injected into a mold to which a magnetic field is applied to form a magnet piece 36, which is then demagnetized, and then magnetized as shown in Figs. 10 and 11.
  • the magnet pieces 36 are re-magnetized by placing the magnets 51 to 53, and the pieces 36 are incorporated into the magnet roller 21 manufactured to have a cross section shown in FIG.
  • the magnetic force distribution in the axial direction of the zero Gaussian band NO of the magnet roller 21 of this embodiment was measured, and the magnet piece 36 was mounted without the magnetized yoke 53 of the magnetized yokes shown in FIG. It was compared with the magnetic force distribution of a conventional magnet roller formed by magnetizing.
  • the method of manufacturing the magnet roller of the conventional example is exactly the same as the method of manufacturing the magnet roller of the embodiment except that the magnetizing yoke 53 is not provided.
  • the outer diameter of the magnet roller used in this comparison is 14.5 mm.
  • the outer diameter of the sleeve arranged on the outer periphery of the magnet roller is 16 mm. Therefore, when measuring the magnetic force of the magnet roller, the tip of the measurement probe is separated from the axis of the magnet roller by 8 mm. It was placed at the position.
  • Table 1 shows the measurement results of the magnetic force distribution in the axial direction of the zero-us band of the magnet roller of the embodiment and the conventional example, and the minimum value from the maximum value of the end magnetic force and the maximum magnetic force in the effective range of the axial magnetic force, respectively. It is shown by magnetic force variation from which magnetic force is subtracted.
  • the maximum value of the magnetic force at the end of the magnet roller and the variation in magnetic force are 4 mT, It is 3 mT, and Table 1 shows that the magnetic force distribution in the zero gauss band, which is not allowed by the conventional magnet roller, has been improved to an acceptable level by the magnet roller manufactured by the manufacturing method of the embodiment.
  • a strong magnetic field is formed in the molding cavity, particularly at the portion of the magnetization yoke closest to the molding cavity.
  • the circumferential magnetic force pattern of the plastic magnet can be adjusted as required. Modifications or changes can be easily achieved in a short time without requiring much know-how as in the prior art, and also enable constant injection molding of plastic magnets. Can be.
  • the magnet piece is magnetized so that the magnetic force at both ends in the axial direction is lower than the magnetic force at the central portion in the axial direction at least in a part in the circumferential direction. Since the magnet roller is manufactured by combining this magnet piece with the remaining magnet pieces, it is possible to manufacture the entire magnet roller having a uniform magnetic force distribution in the axial direction without adjusting the magnetic force.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Dispersion Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)

Abstract

La présente invention a pour objet le moulage d'un aimant plastique par injection d'une matière de résine mélangée à une poudre magnétique composée dans une cavité de moule (3). Selon l'invention, un champ magnétique est produit par une culasse de magnétisation (4), un champ magnétique important est produit dans la cavité de moule (3) par une projection de faible largeur (5) de la culasse de magnétisation (4), et un champ magnétique relativement faible est produit par une partie en retrait (7) formée dans une zone prédéterminée sur un côté de cette zone à champ magnétique important. Ainsi, un motif de force magnétique circonférentielle requis pour l'aimant plastique est réalisé en un temps limité sans faire appel à beaucoup de connaissances techniques. En particulier, lors de la réalisation d'un cylindre magnétique par combinaison de pièces magnétiques, la force magnétique produite à une extrémité axiale du cylindre magnétique est pratiquement égale à celle au niveau de la partie centrale. Ainsi, l'invention concerne un procédé permettant la réalisation d'un cylindre magnétique en faisant intervenir la régulation d'une force magnétique par rectification d'un cylindre magnétique formé.
PCT/JP2002/007073 2001-07-26 2002-07-11 Procede destine au moulage d'un aimant plastique, et culasse de magnetisation utilisee a cet effet, et procede destine a la realisation d'un cylindre magnetique WO2003011558A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2001-225414 2001-07-26
JP2001225414 2001-07-26
JP2001-387371 2001-12-20
JP2001387371A JP2003188011A (ja) 2001-12-20 2001-12-20 マグネットローラの製造方法

Publications (1)

Publication Number Publication Date
WO2003011558A1 true WO2003011558A1 (fr) 2003-02-13

Family

ID=26619287

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2002/007073 WO2003011558A1 (fr) 2001-07-26 2002-07-11 Procede destine au moulage d'un aimant plastique, et culasse de magnetisation utilisee a cet effet, et procede destine a la realisation d'un cylindre magnetique

Country Status (2)

Country Link
CN (1) CN100513124C (fr)
WO (1) WO2003011558A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007143867A2 (fr) * 2006-06-12 2007-12-21 Habasit Ag Module de courroie avec propriétés magnétiques

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103631115A (zh) * 2012-08-22 2014-03-12 大地磁性材料(香港)有限公司 一种磁辊的制造方法及其系统
CN103240416B (zh) * 2013-05-03 2015-01-14 浙江中元磁业股份有限公司 一种制造钕铁硼辐射取向环磁体的方法及其模具
CN106003560A (zh) * 2016-05-25 2016-10-12 北京小米移动软件有限公司 磁性注塑件的加工工艺

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60144911A (ja) * 1984-01-05 1985-07-31 Matsushita Electric Ind Co Ltd 磁気ブラシ現像用磁石ロールの製造方法
JPH01115109A (ja) * 1987-10-28 1989-05-08 Matsushita Electric Ind Co Ltd マグネットロールの製造方法
JPH07271192A (ja) * 1994-03-31 1995-10-20 Matsushita Electric Ind Co Ltd マグネットロールおよびその製造方法
JPH11162731A (ja) * 1997-09-26 1999-06-18 Ricoh Co Ltd マグネット部材、該マグネット部材の製造方法、該マグネット部材の着磁装置、マグネット構造体、マグネット装置、現像ローラ、並びに現像装置
US6021296A (en) * 1997-03-06 2000-02-01 Bridgestone Corporation Magnet roller and manufacturing method thereof
JP2000153540A (ja) * 1998-11-19 2000-06-06 Bridgestone Corp 樹脂磁石成形物の製造方法
JP2000235066A (ja) * 1999-02-15 2000-08-29 Canon Inc 磁性粒子の配向分布解析装置及び方法
JP2002031955A (ja) * 2000-07-17 2002-01-31 Ricoh Co Ltd 現像ローラ、その製造方法及び現像装置

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60144911A (ja) * 1984-01-05 1985-07-31 Matsushita Electric Ind Co Ltd 磁気ブラシ現像用磁石ロールの製造方法
JPH01115109A (ja) * 1987-10-28 1989-05-08 Matsushita Electric Ind Co Ltd マグネットロールの製造方法
JPH07271192A (ja) * 1994-03-31 1995-10-20 Matsushita Electric Ind Co Ltd マグネットロールおよびその製造方法
US6021296A (en) * 1997-03-06 2000-02-01 Bridgestone Corporation Magnet roller and manufacturing method thereof
JPH11162731A (ja) * 1997-09-26 1999-06-18 Ricoh Co Ltd マグネット部材、該マグネット部材の製造方法、該マグネット部材の着磁装置、マグネット構造体、マグネット装置、現像ローラ、並びに現像装置
JP2000153540A (ja) * 1998-11-19 2000-06-06 Bridgestone Corp 樹脂磁石成形物の製造方法
JP2000235066A (ja) * 1999-02-15 2000-08-29 Canon Inc 磁性粒子の配向分布解析装置及び方法
JP2002031955A (ja) * 2000-07-17 2002-01-31 Ricoh Co Ltd 現像ローラ、その製造方法及び現像装置

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007143867A2 (fr) * 2006-06-12 2007-12-21 Habasit Ag Module de courroie avec propriétés magnétiques
WO2007143867A3 (fr) * 2006-06-12 2008-02-07 Habasit Ag Module de courroie avec propriétés magnétiques
US7597188B2 (en) 2006-06-12 2009-10-06 Habasit Ag Belt module with magnetic properties

Also Published As

Publication number Publication date
CN100513124C (zh) 2009-07-15
CN1538902A (zh) 2004-10-20

Similar Documents

Publication Publication Date Title
WO2003011558A1 (fr) Procede destine au moulage d'un aimant plastique, et culasse de magnetisation utilisee a cet effet, et procede destine a la realisation d'un cylindre magnetique
JP2005189811A (ja) 現像ローラ、現像装置、プロセスカートリッジ及び画像形成装置
US20010048827A1 (en) Developing roll, developing device using the same and electrophotographic apparatus
KR20120107691A (ko) 자성롤 및 이의 제조방법
JP2003188011A (ja) マグネットローラの製造方法
JP2007105992A (ja) マグネットローラの製造方法
JP2003109835A (ja) プラスチックマグネットの成形方法およびそれに用いる着磁ヨーク
JP5602550B2 (ja) マグネットローラ成形用金型およびマグネットローラの製造方法
JP2003203817A (ja) マグネットローラの製造方法
JP5890109B2 (ja) マグネットローラ成形用金型
JP4358671B2 (ja) マグネットローラ成型用金型
JPH0338673A (ja) マグネットローラの製造方法
JPH10189336A (ja) マグネットローラの着磁方法と装置およびマグネットローラ及び該マグネットローラを用いた電子写真形成方法と装置
JPH05267049A (ja) マグネットロール
JP2000164443A (ja) 樹脂磁石成形物の製造方法
JPH06231941A (ja) マグネットロール及びその製造方法
JP2006018061A (ja) マグネットローラ
JP2906211B2 (ja) マグネットロールの成形方法および成形用金型
JP3092415B2 (ja) 現像装置
JP4798896B2 (ja) マグネットローラの成型用金型
JPS6338968A (ja) 現像装置
JP2007105989A (ja) マグネットローラの製造方法
JP3002380B2 (ja) 現像装置及び現像ロール
JP5937393B2 (ja) マグネットローラ成形用金型
JP2007184376A5 (fr)

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE ES FI GB GD GE GH GM HR HU ID IL IN IS KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NO NZ OM PH PL PT RO RU SD SE SG SI SK SL TJ TM TN TR TT TZ UA UG US UZ VN YU ZA ZM ZW

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BY BZ CA CH CN CO CR CU CZ DE DM DZ EC EE ES FI GB GD GE GH HR HU ID IL IN IS KE KG KP KR KZ LK LR LS LT LU LV MA MD MG MK MW MX MZ NO NZ OM PH PL PT RO SD SE SG SI SK SL TJ TM TN TR TT UA UG US UZ VN YU ZA ZM

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ UG ZM ZW AM AZ BY KG KZ RU TJ TM AT BE BG CH CY CZ DK EE ES FI FR GB GR IE IT LU MC PT SE SK TR BF BJ CF CG CI GA GN GQ GW ML MR NE SN TD TG

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LU MC NL PT SE SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 20028147472

Country of ref document: CN

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase