JP2005303115A - Metal mold for molding magnet roller and magnet piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that magnetic grain orienting yokes can not be arranged on parting lines, when the parting lines are set on the same line in the molding of a shaft-integrated magnet roller, and magnetic grains cannot be oriented in a state of inclined from the radial direction center line of a magnetic piece, when the parting lines are set on the same line in the molding of the magnet piece. <P>SOLUTION: In the molding of the shaft-integrated magnet roller 7, metal mold constitution is adopted a the structure, where the parting lines 4 of two divided split molds are not set on the same line. In the molding of the magnet piece 3 also, metal mold constitution is adopted in the structure, where the parting lines of two divided split molds are not set on the same line. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnet roller incorporated in an image forming apparatus such as a copying machine, a printer, or a facsimile.

  In general, a magnet roller and a magnet piece molding die incorporated in an image forming apparatus using powder toner in a copying machine, a printer, a facsimile machine, and the like are configured as follows.

(1) Using the same resin magnet material for both the shaft part and the magnet main body part, a magnet mold is formed by injection molding while applying a magnetic field in a split mold with a parting line on the same line. (Patent Document 1) or (2) In a split mold with a parting line on the same line, a magnet piece is formed by injection molding while applying a magnetic field, and then a plurality of magnet pieces are arranged on the shaft. A magnet roller is formed by sticking them together (Patent Document 2).
Japanese Utility Model Sho 64-13116 JP-A-9-68866

  However, as shown in Patent Document 1, when the parting line of the magnet roller mold is on the same line, it becomes difficult to dispose the magnetic particle orientation yoke on the parting line, so that the desired position can be obtained. The magnetic pole may not be formed.

  Moreover, as shown in Patent Document 2, when the parting line of the magnet piece mold is on the same line, the magnetic particles are oriented from the arc side of the outer peripheral surface to the other three sides, Although it is possible to orient the magnetic particles of the magnet piece as shown in FIG. 1, it is possible to orient the magnetic particles so as to be inclined with respect to the radial center line 6 of the magnet piece as shown in FIG. There are cases where it is not possible.

  The magnet roller molding die of the present invention is a split mold for split split molding, in which the parting lines of the split molds of the mold are not on the same line. The degree of freedom of arrangement of the permanent magnets or electromagnets for the orientation and magnetization of the main body is improved, and it can cope with various magnetic pole positions.

  Moreover, the mold for molding the magnet piece of the present invention is a split mold for split mold molding, and the parting line of each split mold of the mold is not on the same line. Since the magnet piece can be tilted with respect to the applied magnetic field (parallel magnetic field), the magnetic particles can be tilted and oriented with respect to the radial center line of the magnet piece.

  According to the present invention (Claim 1), the degree of freedom of arrangement of the permanent magnets or electromagnets for orientation and magnetization of the magnet roller main body is improved, and various magnetic pole positions can be handled.

  Further, according to the present invention (Claim 2), the magnetic particles can be tilted and oriented with respect to the radial center line of the magnet piece.

  The present invention is a two-part split mold for a magnet roller, wherein a parting line for each split part of the mold is not on the same line. .

  In conventional split molds for magnet rollers, the parting lines for the split molds are on the same line, and it is difficult to provide magnetic poles on the parting line of the magnet roller body. It was.

  In the present invention, for example, as shown in FIG. 3, a step is provided in each parting line 4 of each split mold so as not to be on the same line. Conventionally, a magnetic particle orientation and magnetization yoke can be provided at a position where the parting line 4 is formed, and a magnetic pole can be provided at a desired magnetic pole position.

  Here, when the parting line of each split mold of the mold is shifted from the same line (passing through the center of the magnet roller body), taking out the molded product from the mold (cavity) becomes a problem. By devising in this way, it becomes possible to take out. When the parting line 4 is provided as shown in FIG. 3, the molded product is projected vertically as indicated by an arrow 10 with respect to the straight line connecting the contact 8 and the contact 9 between the parting line and the molded product. Can be removed from the mold. When the parting line 4 is provided as shown in FIG. 4, the molded product may be taken out in the axial direction.

  First, in the case of molding a magnet roller, using the mold shown in FIG. 3, a molten resin magnet is injected from the injection port with an electromagnet or a permanent magnet, and 240 K · A / m˜ The magnetic particles are injected while applying a magnetic field of 2400 K · A / m, and the magnetic particles are oriented and magnetized in a desired direction and cured to obtain a shaft-integrated magnet roller as shown in FIG.

  By using the mold structure as described above, the degree of freedom of the magnetic pole position of the magnet roller main body is increased, and a complicated magnetic flux density pattern can be obtained with low cost and high accuracy. The peelability of the agent is improved, and high image quality is possible.

  Also, the present invention is a magnet mold for splitting a magnet piece, wherein the parting lines of the split molds of the mold are not on the same line. It is.

  Although it is possible to orient the magnetic particles of the magnet piece as shown in FIG. 1, it is difficult to orient the magnetic particles with respect to the radial center line 6 of the magnet piece as shown in FIG. It was. When the mold structure as shown in FIG. 20 is used, the orientation direction of the magnetic particles of the magnet piece can be tilted. However, in order to take out the magnet piece, a part of the magnet piece as shown in 50 parts of FIG. It must be cut, and the magnetic properties of the magnet piece are reduced, and the adhesion area between the adjacent magnet piece and the shaft is reduced, and the adhesive strength is reduced.

  In the present invention, for example, as shown in FIG. 6, the parting lines 4 are provided at the leftmost and rightmost positions of the molded product. That is, a step is provided in the parting line so that it is not on the same line. As a result, the magnet piece can be tilted with respect to the applied magnetic field (parallel magnetic field), so that the magnetic particles can be tilted and oriented with respect to the radial center line of the magnet piece. In this case, since there is no undercut portion with respect to the parting line, the molded product can be ejected.

  In the case of molding a magnet piece, for orientation magnetization using a mold similar to that shown in FIG. 6 (a to e in FIG. 11), a molten resin magnet is arranged in the mold with an electromagnet or a permanent magnet from the inlet. Injecting while applying a magnetic field of 240 K · A / m to 2400 K · A / m with a yoke, magnetic particles are oriented and magnetized in a desired direction and cured to obtain magnet pieces 14 to 18 as shown in FIG. . Since the obtained magnet piece is molded in a mold by injection molding, the dimensional accuracy is much better than that of an extrusion molded product, and the outer circumference of the magnet is bonded to the shaft like a mag piece of an extrusion molded product. Post-processing such as outer peripheral cutting for aligning and cutting with high accuracy in the length direction is unnecessary, and a magnet piece with high dimensional accuracy can be obtained at low cost. A plurality of these magnet pieces are bonded on the shaft to form a magnet roller.

  Further, the range of the orientation and magnetization direction of the magnetic particles of the magnet piece is desirably 5 ° ≦ θ1 ≦ 90 ° and −5 ° ≦ θ2 ≦ −90 ° as shown in FIG. If it is less than 5 ° or -5 °, the effect of tilting the magnetic particles with respect to the radial center line 6 of the magnet piece is not achieved, and exceeding 90 ° or -90 ° means that the polarity of the magnet piece is reversed. It becomes the same as tilting, and it makes sense.

  Therefore, by combining the magnet pieces with the tilted orientation as described above, a complicated magnetic flux density pattern can be realized at low cost and with high accuracy, and developer transportability, developer peelability, etc. are improved. High image quality is possible.

  The magnet roller and magnet piece are mainly composed of a mixture of 50% to 95% by weight of anisotropic ferrite magnetic powder and 5% to 50% by weight of a resin binder, and if necessary, a surface treatment agent. Addition of silane and titanate coupling agents, polystyrene and fluorine lubricants that improve fluidity, stabilizers, plasticizers, or flame retardants, etc., mix and disperse, melt knead, pellet form After molding to injection molding.

  The orientation magnetization magnetic field applied at the time of molding may be appropriately selected according to the magnetic flux density specification required for each magnetic pole. Further, depending on the required magnetic properties, the orientation magnetization magnetic field may not be applied at the time of molding, and may be magnetized after molding.

Examples of the magnetic powder include anisotropic ferrite magnetic powder having a chemical formula represented by MO.nFe ₂ O ₃ (n is a natural number). As M in the formula, one or more of Sr, Ba, lead and the like are appropriately selected and used.

  As the resin binder, if it is a thermoplastic resin, for example, vinyl chloride-vinyl acetate copolymer, ethylene-ethyl acrylate resin, polyamide resin, polystyrene resin, PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PPS. If it is a thermosetting resin such as (polyphenylene sulfide), EVA (ethylene-vinyl acetate copolymer), EVOH (ethylene-vinyl alcohol copolymer), CPE (chlorinated polyethylene) and PVC (polyvinyl chloride), epoxy is used. Examples thereof include resins, phenol resins, urea resins, unsaturated polyester resins, melamine resins, furan resins, and polyimide resins. These may be used alone or in combination of two or more.

  Further, depending on the required magnetic flux density, as magnetic powder, anisotropic ferrite magnetic powder, isotropic ferrite magnetic powder, anisotropic rare earth magnetic powder (for example, SmFeN system), isotropic rare earth magnetic powder (for example, NeFeB system) May be used alone or in admixture of two or more.

  If the content of the single magnetic powder or the mixed magnetic powder shown above is less than 50% by weight, the magnetic properties of the magnet roller and the magnet piece are deteriorated due to insufficient magnetic powder, and it is difficult to obtain a desired magnetic force. If the ratio exceeds 95% by weight, the binder may be insufficient and the moldability may be impaired.

  The magnet pieces used in the present invention need not all be made of the same material (binder, magnetic powder, etc.), so even if different kinds of magnet pieces are arbitrarily combined to match the magnetic characteristics, the cost can be reduced. Good.

  Further, in this specification, a magnet roll having a five-pole configuration is illustrated, but the present invention is not limited to a five-pole magnet roll. That is, the number of magnetic poles or the number of magnet pieces of the magnet roller main body integrated with the shaft may be selected according to the desired magnetic flux density and magnetic field distribution, and the number of magnetic poles and the magnetic pole position may be set as appropriate.

  In addition, when a magnetic field is applied at the same time as molding, a post-molding die is used to improve the demoldability of the molded product, to prevent dust from adhering to the molded product's magcus, and to facilitate handling of the magnet roller and magnet piece. It may be demagnetized once inside or outside the mold and then magnetized.

  Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1
As a magnet material, 10% by weight of nylon 6 (P1010 manufactured by Ube Industries Co., Ltd.) as a resin binder (including lubricant, plasticizer and stabilizer) and anisotropic strontium ferrite magnetic powder (SrO.6Fe ₂ O ₃ as magnetic powder) ) Is 90 wt%, these are mixed, melt-kneaded, formed into pellets, the pellets are melted, and the molten resin magnet material is injected and injected from the inlet 21 of FIG. Orientation and magnetization were applied while applying a magnetic field of ˜1200 K · A / m, and the magnet roller shown in FIG. 5 was formed. The outer diameter of the magnet roller main body was 13.6 mm, the length of the magnet main body was 320 mm, and the outer diameter of the shaft was 6 mm.

  In this case, the contact point between the parting line and the molded product is 8 and 9, as shown in FIG. 3, and the direction perpendicular to the straight line connecting 8 and 9 (passing through the center point of the magnet roller), that is, the arrow of 10 The magnet roller was taken out in the direction.

  The probe (magnetic flux density sensor) is set at a position 8 mm away from the center of the magnet roller (on the sleeve) while supporting the shafts on both ends of the obtained magnet roller and rotating the magnet roller. The circumferential magnetic flux density pattern was measured.

  The measurement results are shown in FIG.

(Example 2)
The same procedure as in Example 1 was performed except that the mold shown in FIG. 4 was molded and the molded product was taken out from the mold in the axial direction.
The measurement results are shown in FIG.

Example 3
As a magnet material, 10% by weight of nylon 12 (P3012U manufactured by Ube Industries, Ltd.) as a resin binder (including lubricant, plasticizer and stabilizer), anisotropic strontium ferrite magnetic powder (SrO.6Fe ₂ O ₃ ) as magnetic powder ) Is 90% by weight, these are mixed, melt-kneaded, formed into pellets, the pellets are melted, and the molten resin magnet material is injected and injected from the inlet 21 of FIG. 11, and 240 K · A / m Orientation and magnetization were applied while applying a magnetic field of ˜2400 K · A / m, and magnet pieces 14 to 18 were formed using dies shown in FIGS. 11 a, b, c, d, and e.

  The magnet pieces 14 to 18 were bonded to the outer peripheral surface of the shaft as shown in FIG. 7 to form a magnet roller. The outer diameter of the magnet was φ13.6, the length of the magnet main body was 320 mm, and the shaft was SUM22 (magnetic material) having an outer diameter of φ6.

  The probe (magnetic flux density sensor) is set at a position 8 mm away from the center of the magnet roller (on the sleeve) while supporting the shafts at both ends of the obtained magnet roller and rotating the magnet roller. The circumferential magnetic flux density pattern was measured.

  The measurement results are shown in FIG.

Example 4
As a magnetic material, 10% by weight of ethylene ethyl acrylate (DPDJ-9169 manufactured by Nihon Unicar) is used as a resin binder, and 90% of anisotropic strontium ferrite magnetic powder (SrO.6Fe ₂ O ₃ ) is used as magnetic powder. These are mixed, melt-kneaded, formed into pellets, the pellets are melted, and a molten resin magnet material is injected and injected from the injection port 21 in FIG. 12, from 240 K · A / m to 2400 K · Orientation and magnetization were applied while applying a magnetic field of A / m, and magnet pieces 31 to 35 were formed using dies shown in a, b, c, d and e of FIG.

  The magnet pieces 31 to 35 were bonded to the outer peripheral surface of the shaft as shown in FIG. 13 to form a magnet roller. The outer diameter of the magnet was φ18, the length of the magnet main body was 320 mm, and the shaft used was a SUM22 (magnetic material) of 6 mm square (regular square).

  The probe (magnetic flux density sensor) is set at a position (on the sleeve) 10 mm away from the center of the magnet roller while rotating the magnet roller while supporting the shafts at both ends of the obtained magnet roller, The circumferential magnetic flux density pattern was measured.

  The measurement results are shown in FIG.

(Comparative Example 1)
As shown in FIG. 14, except that the parting line of each split mold of the mold is on the same line (also passes through the center of the magnet roller), and the magnet roller is molded using a mold having an orientation magnetizing yoke,
The same operation as in Example 1 was performed.

  The measurement results are shown in FIG.

(Comparative Example 2)
15 except that the magnet pieces 36 to 40 are molded with the molds shown in FIGS. 15a, 15b, 15c, 15d, 15e, and each magnet piece is attached to the shaft as shown in FIG. went.

  The measurement results are shown in FIG.

(Comparative Example 3)
With the molds shown in FIGS. 16a, b, c, d and e, the magnet pieces 41 to 45 are molded,
As shown in FIG. 19, the same procedure as in Example 4 was performed except that each magnet piece was attached to the shaft.

The measurement results are shown in FIG.

Comparing Examples 1 and 2 (a and b in FIG. 10) and Comparative Example 1 (a in FIG. 17), Examples 1 and 2 are different from Comparative Examples in that the magnetic poles are changed by changing the position of the parting line. It can be seen that the degree of freedom of position is increased, and various magnetic flux density patterns can be handled.

  Comparing Example 3 (FIG. 10c) and Comparative Example 2 (FIG. 17b), the N1 pole of Example 3 (FIG. 10c) is a line connecting the magnet roller center and the magnetic flux density peak position. On the other hand, the magnetic flux density pattern of the N1 pole is asymmetric. The same can be said for the S1 pole and S2 pole of Example 3. On the other hand, for the N1 pole of Comparative Example 2 (FIG. 17B), the magnetic flux density pattern of the N1 pole is substantially symmetric with respect to the line connecting the magnet roller center and the magnetic flux density peak position. Therefore, as in Example 3, by tilting the magnetic particle orientation magnetization of the magnet piece, a complex magnetic flux density pattern is possible, and carrier adhesion, developer transportability, peelability, etc. are improved. Image quality is possible.

Comparing Example 4 (FIG. 10d) and Comparative Example 3 (FIG. 17c), the N1 pole of Example 4 (FIG. 10d) is a line connecting the magnet roller center and the magnetic flux density peak position. On the other hand, the magnetic flux density pattern of the N1 pole is asymmetric. The same can be said for the S1 pole and the S2 pole of Example 4. On the other hand, for the N1 pole in Comparative Example 3 (FIG. 17c), the magnetic flux density pattern of the N1 pole is substantially symmetric with respect to the line connecting the magnet roller center and the magnetic flux density peak position. Therefore, as in Example 4, by tilting the magnetic particle orientation magnetization of the magnet piece, a complex magnetic flux density pattern is possible, and carrier adhesion, developer transportability, peelability, etc. are improved. Image quality is possible.

Conventional magnet piece mold Magnet piece cross section with tilted magnetic particle orientation direction The shaft-integrated magnet roller molding die of the present invention Another shaft-integrated magnet roller molding die of the present invention The shaft-integrated magnet roller perspective view of the present invention Magnet piece molding die of the present invention The figure and magnetic flux density pattern in which the magnet pieces of the present invention are bonded together The figure explaining the magnetic particle orientation direction of the magnet piece of this invention Overall view of shaft-integrated magnet roller molding die of the present invention Magnetic flux density measurement pattern of the present invention Magnet piece molding die of the present invention Another magnet piece molding die of the present invention Sectional view when the magnet piece of the present invention is bonded to the shaft Conventional shaft-integrated magnet roller mold Conventional magnet piece mold Another conventional magnet piece mold Conventional magnetic flux density measurement pattern Sectional view when pasting a conventional magnet piece on the shaft Sectional view when another conventional magnet piece is bonded to the shaft Another conventional magnet piece mold

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnet or permanent magnet 2 Magnetic particle orientation magnetizing yoke 3 Magnet piece 4 Parting line 5 Magnetic particle orientation magnetizing direction 6 Radial direction center line of magnet piece 7 Axis-integrated magnet roller 8 Parting line and molded product Contact 9 Contact between the other parting line and molded product 10 Molded product take-out direction 11 Shaft-integrated magnet roller main body 12 Shaft-integrated magnet roller shaft 13 Magnetic flux density measurement pattern 14 Magnet piece 15 Magnet piece 16 Magnet piece 17 Magnet piece 18 Magnet piece 19 Shaft 20 Sleeve 21 Inlet 22 Sleeve outer peripheral surface 23 Magnetic flux density peak position 24 Line connecting magnet roller center and magnetic flux density peak position 31 Magnet piece 32 Magnet peak 33 magnet pieces 34 magnet pieces 35 magnet pieces 36 magnet pieces 37 magnet pieces 38 magnet pieces 39 magnet pieces 40 magnet pieces 41 magnet pieces 42 magnet pieces 43 magnet pieces 44 magnet pieces 45 magnet pieces 50 notch

Claims (2)

  A magnet roller molding die characterized in that it is a two-part split molding die for a magnet roller, and the parting lines of the split molds of the die are not on the same line.   2. A magnet piece mold for splitting a magnet piece, wherein a parting line for each split mold is not on the same line.

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