JP2000298400A - Magnet roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnet roller that makes the best use of the magnetic characteristics of a magnetic rare earth powder while controlling the use of the expensive powder, ensures the desired magnetic force and is manufactured at a low cost. SOLUTION: The magnet roller consists of a body part 2 and shaft parts that support both ends of the body part 2 and has magnetic poles formed in the peripheral surface of the body part 2 along the peripheral direction. The whole or a part of the body part 2 comprises a material obtained by carrying a magnetic powdery mixture of a magnetic rare earth powder and a magnetic ferrite powder on a resin binder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet roller incorporated in an electrophotographic apparatus employing an electrophotographic process in an image forming apparatus such as a copying machine, a laser printer or a facsimile receiving apparatus.

[0002]

2. Description of the Related Art A magnet roller incorporated in an electrophotographic apparatus supplies a toner to an electrostatic latent image carrier and develops the electrostatic latent image by developing the toner. This is applied to a cleaning roller or the like for removing the residual toner on the electrostatic latent image carrier after the transfer to the electrostatic latent image carrier. For example, when a magnet roller is used as a developing roller, as shown in FIG.
Shafts 32a, 32 are provided at both ends of a main body 31 made of a magnetic material.
b and is used by being incorporated in a hollow cylindrical sleeve 33 made of an aluminum alloy or the like. A plurality of magnetic poles are magnetized on the outer peripheral surface of the main body 31, and the one having the highest surface magnetic flux density among these magnetic poles is usually called a main magnetic pole and is often used as a developing pole. .

[0003] The main body 31 is mainly made of a thermoplastic resin or a thermosetting resin such as nylon or polypropylene;
A strontium-based or barium-based ferrite magnetic powder (for example, intrinsic coercive force iHc = about 3 KOe; residual magnetic flux density Br = about 4.8 KG) is mixed and dispersed, and molded using an extrusion method or an injection molding method. It is manufactured by performing orientation magnetization with a low magnetic field (about 8 to 15 KOe) at the same time as molding, or by magnetizing with a low magnetic field after molding.

[0004]

However, a main body (outer diameter of 13.6 mm) using this type of ferrite magnetic powder is used.
The magnetic force of the magnet roller having
It was about 00G, and could not meet the demand for high magnetic force of 850G or more. This is because even if this kind of magnet roller is magnetized with a high magnetic field (about 30 KOe or more), it is difficult to obtain a high magnetic force of 850 G or more due to magnetic saturation.

Therefore, in recent years, high magnetic force (about 1400 G)
A magnet roller using a rare earth magnetic powder capable of obtaining the above is being adopted. However, since rare-earth magnetic powder is very expensive, it does not meet the cost reduction requirement accompanying the intense price competition in recent years, and the magnetic force required for an actual magnet roller is sufficient if it is about 1200 G to 1300 G at maximum. Therefore, at present, the level of the magnetizing magnetic field of the magnet roller using the rare earth magnetic powder is adjusted slightly lower. For example, when a magnet roller having a magnetic force exceeding 1300 G is used, problems such as a decrease in image quality density, a drop in an image, and a rapid deterioration of a developer occur. Therefore, this type of magnet roller cannot be said to make the most of the original magnetic properties of the rare earth magnetic powder.

In view of the above circumstances, the present invention seeks to solve the above problem by suppressing the use of expensive rare earth magnetic powder while maximizing the magnetic characteristics of the rare earth magnetic powder, thereby obtaining a desired magnetic force (8).
Another object of the present invention is to provide a magnet roller which can obtain 50 G to 1300 G) and can be manufactured at low cost.

[0007]

In order to achieve the above-mentioned object, a magnet roller according to the present invention comprises a main body and a shaft supporting both ends of the main body. In a magnet roller having magnetic poles extending in all directions, the whole or a part of the main body portion is made of a material in which a mixed magnetic powder of a rare earth magnetic powder and a ferrite magnetic powder is supported by a resin binder. Things.

Here, in particular, the rare earth magnetic powder (A) and the ferrite magnetic powder (B) of the mixed magnetic powder are mixed with A: B = 1: 9.
It is preferable to mix them in a weight ratio of ９9: 1.

Further, as the rare earth magnetic powder, it is more preferable to use an exchange spring magnetic powder having a multiple phase of a hard magnetic phase and a soft magnetic phase that magnetically exchange and interact.
Here, “exchange spring magnetism” means that when a large amount of soft magnetic phase exists in the magnet, the magnetization of the crystal grains of the soft magnetic phase and the hard magnetic phase are connected to each other by exchange interaction, so that the original value is low. The magnetization of the soft magnetic phase, which easily reverses in a reversed magnetic field without magnetic force, becomes difficult to reverse even in a reversed magnetic field, as if both phases were connected by a spring.
It refers to magnetic properties as if it were a single phase consisting of only a hard magnetic phase (for example, “R. Coehoorn, KHJ Buschow et al .: J.
de Phys. 49 (1988) C8-669 "). Specific examples of such exchange spring magnetic powder include those using a rare earth-iron-boron compound phase as a hard magnetic phase, an iron phase or an iron-boron compound phase as a soft magnetic phase, or rare earth-iron as a hard magnetic phase. Those using an iron phase as the iron-nitrogen compound phase and the soft magnetic phase are preferable.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the magnet roller according to the present invention will be described below. As shown in the schematic cross-sectional view of FIG. 1, the magnet roller 1 according to the present invention includes a cylindrical main body 2 and a support shaft 3 disposed on the axis of the main body 2. Are formed by forming magnetic poles (N1, S1, N2, and S2 poles) on the outer peripheral surface in the circumferential direction. At both ends of the support shaft 3 in the axial direction, shaft portions (not shown) mounted on bearings (not shown) of the electrophotographic apparatus are formed. However, the present invention is not limited to this. The shaft may be formed by press-fitting, bonding or pinning. Further, in the present embodiment, 4
Although the magnetic pole is magnetized, the present invention is not limited to this, and the number of magnetic poles and the magnetic pole position may be appropriately set according to a desired magnetic force and magnetic field distribution.

The main body 2 is mainly composed of a mixture of 50 to 95% by weight of a mixed magnetic powder composed of a rare earth magnetic powder and a ferrite magnetic powder and 5 to 50% by weight of a resin binder. Depending on the surface treatment agent, a silane-based or titanate-based coupling agent, an amide-based lubricant as a lubricant for improving the flowability of the molten magnet material, a stabilizer for preventing thermal decomposition of the resin binder, or a flame retardant, etc. The added magnetic material is mixed and dispersed, melt-kneaded, and formed into pellets, and then manufactured by an injection molding method or an extrusion molding method. If the content of the mixed magnetic powder is less than 50% by weight, the magnetic properties of the magnet roller are deteriorated due to the shortage of the magnetic powder, and a desired magnetic force (850 G or more at the main magnetic pole) cannot be obtained, and the content is 95% by weight. If the ratio exceeds the range, the binder becomes insufficient and the moldability of the main body is impaired. Examples of the resin binder include ethylene-ethyl acrylate resin, polyamide resin, polyethylene resin, polystyrene resin, PET (polyethylene terephthalate), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), and EV.
A (ethylene-vinyl acetate copolymer), one or more of EVOH (ethylene-vinyl alcohol copolymer) and PVC (polyvinyl chloride), or epoxy resin, phenol resin, urea resin, melamine resin One or two or more kinds of thermosetting resins such as furan resin, unsaturated polyester resin and polyimide resin can be used.

The magnetization of the main body 2 is 8 to 30K.
By applying a magnetizing magnetic field of about Oe, it is formed by orientation magnetization simultaneously with molding such as injection molding or extrusion molding, or by magnetizing after molding. Further, after such magnetization, the magnet may be demagnetized once and then remagnetized to remove internal strain and facilitate demolding.

The mixing ratio of the rare earth magnetic powder (A) and the ferrite magnetic powder (B) in the mixed magnetic powder is adjusted so as to maximize the magnetic properties of the rare earth magnetic powder. It is preferable to adjust the weight ratio of A: B to be in the range of 1: 9 to 9: 1. From the viewpoint of further reducing the mixing ratio of the rare earth magnetic powder and reducing the cost, A: B =
It is preferable to adjust within the range of 2: 8 to 8: 2. When the mixing ratio is less than 1: 9, the content of the rare earth magnetic powder is small, so that only a magnetic force comparable to that of a conventional ferrite resin magnet can be obtained. On the other hand, when the mixing ratio exceeds 9: 1, the rare earth magnetic powder is used as a magnetic powder. Although a high magnetic force can be obtained as in a conventional magnet roller using only powder, a magnetic pole having a magnetic force exceeding a desired range is magnetized, the specification of the magnet roller is wasted, and the manufacturing cost increases.

The rare earth magnetic powder includes R (rare earth element) —Fe—N alloy, R—Fe—B alloy, R
-Co-based alloys, R-Fe-Co-based alloys and the like are preferable, and among these, exchange spring magnetic powders having a structure including a soft magnetic phase and a hard magnetic phase and having a structure in which the magnetizations of both phases exchange and interact with each other are preferred. More preferred. Since the exchange spring magnetic powder has a low coercive force (intrinsic coercivity (iHc) of about 5 KOe or less) coming from the soft magnetic phase and a high residual magnetic flux density (about 5 KG or more) coming from the exchange interaction, it is relatively Since a magnetic pole having a desired magnetic force can be formed with a small magnetizing magnetic field (about 15 KOe or less), the size of the magnetizing device and the simplification of the magnetizing process can be realized, and the manufacturing cost can be further reduced. . When a rare-earth magnetic powder consisting of only a normal hard magnetic phase is used, a high magnetic force can be obtained, but the level of the magnetizing magnetic field needs to be large (about 20 KOe or more) due to a high coercive force. Inevitably, an increase in the size of the device and an increase in the power consumption are inevitable, which has been a factor of increasing the manufacturing cost.

The R (rare earth element) is preferably Sm, Nd, and one or a combination of two or more of Pr, Dy, Tb, etc.
In order to improve magnetic properties by substituting a part of Fe, Co, Ni, Cu, Zn, Ga, Ge, Al, S
i, Sc, Ti, V, Cr, Mn, Zr, Nb, Mo,
Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, S
b, Hf, Ta, W, Re, Os, Ir, Pt, Au,
One or more of elements such as Hg, Tl, Pb, and Bi can be added. Among them, the exchange spring magnetic powder includes those using an R-Fe-B compound phase as a hard magnetic phase and an Fe phase or an Fe-B compound phase as a soft magnetic phase, or R-Fe as a hard magnetic phase.
It is preferable to use an -N-based compound phase and an Fe phase as the soft magnetic phase. More specifically, an Nd—Fe—B alloy (soft magnetic phase: Fe—B alloy, αFe), Sm—Fe—N
Alloy (soft magnetic phase: αFe), Nd-Fe-Co-Cu
Exchange spring magnetic powders such as -Nb-B-based alloys (soft magnetic phase: Fe-B alloy, αFe, etc.) and Nd-Fe-Co-based alloys (soft magnetic phase: αFe, etc.) are suitable.
From the viewpoint of lowering the coercive force (iHc) and increasing the residual magnetic flux density (Br), an Nd ₄ Fe ₈₀ B ₂₀ alloy (soft magnetic phase: F
e ₃ B, αFe) and Sm ₂ Fe ₁₇ N ₃ alloy (soft magnetic phase: α
The exchange spring magnetic powder of Fe) is preferred.

A high-speed quenching method, mechanical alloying (mechanical alloying) or the like is used as a method for producing the exchange spring magnetic powder. Specifically, each raw material element is weighed, and a heat treatment is performed on the alloy powder obtained by mechanical alloying, and a nitriding treatment is performed as necessary. After pulverizing an alloy containing an amorphous or near-amorphous microstructure obtained by performing a rapid quenching method according to the above method, performing a heat treatment to precipitate crystals, and, if necessary, performing a nitriding treatment. By appropriately adjusting quenching conditions (roll speed, etc.), pulverizing conditions, heat treatment conditions (treatment time, temperature), etc., an exchange spring magnetic powder having a soft magnetic phase having a crystal grain size of several tens nm can be produced. Incidentally, the nitriding treatment is necessary when producing an R-Fe-N-based exchange spring magnetic powder.

The ferrite magnetic powder includes M
O · nFe ₂ O ₃ (n is a natural number) using an anisotropic or isotropic ferrite magnetic powder having a chemical formula represented by one type or two types of the M in the formula, Sr, etc. Ba or Pb The above is appropriately selected and used.

Next, as another embodiment according to the present invention,
As shown in the schematic sectional view of FIG.
A plurality of semi-fan shaped magnet pieces 12a, 12b, 12c,
12d is attached using an adhesive or a heat-shrinkable tube to form a main body 13. If the cross-sectional shape of the magnet piece is such a semi-fan shape or fan shape, it can be easily shared with other magnet roller magnet pieces, and a jig for attaching the magnet piece can be shared, and further. There is an advantage that the moldability and the sticking property (adhesive property) are remarkably improved as compared with the bonding of magnet pieces having different shapes.
The magnet material and the like of the main body are substantially the same as those in the embodiment shown in FIG. 1, and therefore detailed description is omitted.

As described above, the magnetization of such a magnet piece is formed by orientation magnetization at the same time as molding or by magnetizing after molding, and the method of applying a magnetizing magnetic field depends on the required magnetic force. And it is appropriately selected according to the magnetic pattern shape. For example, (1) as shown in FIG.
And (2) applying a magnetizing magnetic field 15 in the radial direction from the back side to the front side of the magnet piece 12 as shown in FIG. (3) As shown in FIG.
A method of applying the magnetizing magnetic field 16 from the back surface side to the front surface side of the magnet piece 12 while converging the magnetic field distribution to a desired position is exemplified. Thus, the magnet pieces magnetized by the methods (1) to (3) may be attached to the support shaft. For example, only the magnet pieces magnetized by the method (1) may be attached,
A magnet roller magnetized by the methods (1) and (3) may be combined and attached to form a magnet roller, and the method may be appropriately selected according to required specifications.

The cross-sectional shape of the magnet piece is preferably a half fan shape or a fan shape according to the present embodiment. However, the present invention is not limited to this, and may be appropriately determined based on a desired magnetic force or a magnetic pattern shape such as a kamaboko shape. Selected.

[0021]

EXAMPLES Examples according to the present invention and comparative examples will be described below, but the following examples do not limit the present invention in any way.

(Example 1) Rare earth magnetic powder Nd _13.5 Fe
_1.7 B _4.8 (specific coercive force iHc = 14KOe; residual magnetic flux density B
r = 8.4KG), 10% by weight, ferrite magnetic powder Sr
90% by weight of O.6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density Br = 4.8KG) was mixed to prepare a mixed magnetic powder. Next, 90% by weight of the mixed magnetic powder and 10% by weight of the resin binder (nylon 12) are mixed, melt-kneaded, and formed into pellets. After being formed into a roller shape (outer diameter: 13.6 mm; axial length: 320 mm), the magnet was magnetized with a magnetizing magnetic field of magnitude 8 KOe to 30 KOe to form four magnetic poles. Was prepared.

Example 2 Rare earth magnetic powder Nd _13.5 Fe
_1.7 B _4.8 (specific coercive force iHc = 14KOe; residual magnetic flux density B
r = 8.4KG), 20% by weight, ferrite magnetic powder Sr
This procedure was carried out in the same procedure as in Example 1 except that 80% by weight of O.6Fe ₂ O ₃ (intrinsic coercive force iHc = ₃ KOe; residual magnetic flux density Br = 4.8 KG) was blended to form a mixed magnetic powder. Example magnet rollers were made.

Example 3-a Rare earth magnetic powder Nd _13.5
Fe _1.7 B _4.8 (intrinsic coercive force iHc = 14 kOe; remanence Br = 8.4 kg) 50 wt%, the ferrite magnetic powder SrO · 6Fe ₂ O ₃ (intrinsic coercive force iHc = 3 kOe; remanence Br = 4. 8KG) is mixed at 50% by weight to produce a mixed magnetic powder, and the magnitude of the magnetic field applied to the main magnetic pole is reduced to 30 KO.
Except for e, the magnet roller of this example was manufactured in the same procedure as in Example 1.

Example 3-b A magnet roller of this example was produced in the same manner as in Example 3-a, except that the magnitude of the magnetic field applied to the main magnetic pole was changed to 15 KOe.

Example 4 Rare earth magnetic powder Nd _13.5 Fe
_1.7 B _4.8 (specific coercive force iHc = 14KOe; residual magnetic flux density B
r = 8.4KG), 80% by weight, ferrite magnetic powder Sr
This procedure was carried out in the same procedure as in Example 1 except that 20% by weight of O.6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density Br = 4.8KG) was blended to form a mixed magnetic powder. Example magnet rollers were made.

Example 5 Rare earth magnetic powder Nd _13.5 Fe
_1.7 B _4.8 (specific coercive force iHc = 14KOe; residual magnetic flux density B
r = 8.4KG), 90% by weight, ferrite magnetic powder Sr
This procedure was carried out in the same manner as in Example 1 except that 10% by weight of O.6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density Br = 4.8KG) was blended to form a mixed magnetic powder. Example magnet rollers were made.

(Embodiment 6) Exchange spring magnetic powder Nd
₄ Fe ₈₀ B ₂₀ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density
Br = 12KG), 50% by weight of ferrite magnetic powder SrO
50% by weight of 6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density Br = 4.8) is mixed to form a mixed magnetic powder, and the magnitude of the magnetic field applied to the main magnetic pole is set to 15KOe. Prepared the magnet roller of the present embodiment in the same procedure as in the first embodiment.

(Comparative Example 1-a) Ferrite magnetic powder SrO.6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KO) as magnetic powder
e; A magnet roller of this comparative example was manufactured in the same procedure as in Example 1 except that only the residual magnetic flux density Br = 4.8) was used, and the magnitude of the magnetic field applied to the main magnetic pole was set to 30 KOe. did.

(Comparative Example 1-b) A magnet roller of this comparative example was produced in the same manner as in Comparative Example 1-a, except that the magnitude of the magnetizing magnetic field applied to the main magnetic pole was changed to 15 KOe.

Comparative Example 2 Rare Earth Magnetic Powder Nd _13.5 Fe
_1.7 B _4.8 (specific coercive force iHc = 14KOe; residual magnetic flux density B
r = 8.4KG), 5% by weight, ferrite magnetic powder SrO
A magnet roller of this comparative example was produced in the same procedure as in Example 1 except that 95% by weight of 6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density Br = 4.8KG) was blended. .

Comparative Example 3 Rare Earth Magnetic Powder Nd _13.5 Fe
_1.7 B _4.8 (specific coercive force iHc = 14KOe; residual magnetic flux density B
r = 8.4KG), 95% by weight of ferrite magnetic powder Sr
The magnet roller of this comparative example was produced in the same procedure as in Example 1 except that 5% by weight of O.6Fe ₂ O ₃ (intrinsic coercive force iHc = 3KOe; residual magnetic flux density Br = 4.8) was blended. did.

(Comparative Example 4) Nd _13.5 Fe _1.7 B _4.8 (intrinsic coercive force iHc = 14K) which is a rare earth magnetic powder as the magnetic powder
Oe: The magnet roller of this comparative example was manufactured in the same procedure as in Example 1 except that only the residual magnetic flux density Br = 8.4 KG) was used.

The magnetic patterns of the magnet rollers of the above Examples and Comparative Examples were measured in a state of being incorporated in an aluminum alloy sleeve 20, as shown in the schematic sectional view of FIG. In the figure, N1 pole is a main magnetic pole, reference numeral 21 is a support shaft, 22 is a main body, 23 is a magnetic pattern waveform, and point A indicates a maximum value of a magnetic force distribution at the main magnetic pole.

The magnetic pattern was measured by using a Gauss meter, placing a probe at a position 1.2 mm radially away from the surface of the magnet roller, and rotating the magnet roller in the circumferential direction. Table 1 below shows the configuration of each magnet roller (“mixing ratio (rare earth: ferrite)” of the mixed magnetic powder) and its magnetic characteristics (“magnetic characteristics after molding”,
“Magnitude of magnetic field applied to main pole” and “magnetic force of main pole”). The parentheses in the table indicate units of each magnetic characteristic.

[0036]

[Table 1]

From the results shown in Table 1, comparing the magnetic forces of the main magnetic poles, the magnet rollers of Examples 1 to 6 in which the weight ratio of the mixed magnetic powder was adjusted to fall within the range of 1: 9 to 9: 1 850G to 1290G as the magnetic force of the main magnetic pole, whereas the magnet roller using only the ferrite magnetic powder of Comparative Examples 1-a and 1-b can only obtain a magnetic force of 800G. Comparative Example 1-a and Comparative Example 1-
b, although the strength of the magnetizing magnetic field was different, no change was observed in the magnetic force of the obtained main pole, and it was confirmed that magnetic saturation occurred in Comparative Example 1-a.

The weight ratio of Comparative Example 2 was 0.5: 9.
With the magnet roller adjusted to 5, only a magnetic force of 810 G at substantially the same level as in Comparative Example 1 was obtained, and the effect of mixing the rare earth magnetic powder was not exhibited.

The weight ratio of Comparative Example 3 was 9.5: 0.
With the magnet roller adjusted to 5, a magnetic force of 1360 G was obtained, which is almost the same as the magnetic force (1400 G) of the magnet roller of Comparative Example 4 using only the rare-earth magnetic powder. And the possibility of adversely affecting the image quality and the like is high, and the purpose of reducing the manufacturing cost cannot be achieved.

Further, in the magnet roller of Example 6 in which the weight ratio was adjusted to 5: 5, the exchange spring magnetic powder having a lower coercive force (iHc) than the rare earth magnetic powder consisting only of the hard magnetic phase was used. , Low magnetic field (15KOe)
With the same level of magnetic force as in Example 3-a (1110G)
Could be obtained. In contrast, in Example 3-b,
Only a magnetic force of 750 G was obtained by magnetization in a low magnetic field (15 KOe).

Therefore, the magnet roller of the above embodiment can reduce the cost because the amount of the rare earth magnetic powder used can be suppressed, and can achieve the desired magnetic force (850 G to 1300 G).
It was confirmed that G) was obtained. Further, by using the exchange spring magnetic powder as the rare earth magnetic powder, it is possible to magnetize in a low magnetic field (15 KOe). Therefore, it is confirmed that a desired high magnetic force can be obtained even if a magnetizing device for a ferrite resin magnet is used. Was.

[0042]

As described above, according to the magnet roller of the present invention, the whole or a part of the main body is made of a magnetic powder mixed with a rare earth magnetic powder and a ferrite magnetic powder supported by a resin binder. Therefore, the amount of expensive rare earth magnetic powder used can be suppressed, and a desired high magnetic force can be obtained at low cost.

Further, by using an exchange spring magnetic powder having a multiple phase of a hard magnetic phase and a soft magnetic phase which magnetically exchange and interact with each other as the rare earth magnetic powder, a desired magnetic field can be obtained even when magnetized in a low magnetic field. Since a high magnetic force can be obtained, downsizing of the magnetizing device and simplification of the magnetizing process can be realized, and thus the manufacturing cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a magnet roller according to the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the magnet roller according to the present invention.

FIG. 3 is a schematic sectional view showing a magnet roller incorporated in a sleeve.

FIG. 4 is a schematic sectional view showing a side surface of a conventional magnet roller incorporated in a sleeve.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnet roller 2 main body 3 support shaft 10 magnet roller 11 support shaft 12, 12a, 12b, 12c, 12d magnet piece 13 main body 14, 15, 16 direction of magnetizing magnetic field 20 sleeve 21 support shaft 22 main body 30 magnet roller 31 body part 32a, 32b shaft part 33 sleeve

Claims (5)

[Claims] 1. A magnet roller comprising a main body, and a shaft supporting both ends of the main body, wherein a plurality of magnetic poles are formed on an outer peripheral surface of the main body in a circumferential direction. A magnet roller, characterized in that the whole or a part thereof is formed by carrying a mixed magnetic powder of a rare earth magnetic powder and a ferrite magnetic powder with a resin binder. 2. The magnet according to claim 1, wherein the rare earth magnetic powder (A) and the ferrite magnetic powder (B) of the mixed magnetic powder are blended in a weight ratio of A: B = 1: 9 to 9: 1. roller. 3. The magnet roller according to claim 1, wherein said rare earth magnetic powder is an exchange spring magnetic powder having a multiple phase of a hard magnetic phase and a soft magnetic phase that magnetically exchange and interact. 4. The magnet roller according to claim 3, wherein a rare earth-iron-boron compound phase is used as the hard magnetic phase, and an iron phase or an iron-boron compound phase is used as the soft magnetic phase. 5. The magnet roller according to claim 3, wherein a rare earth-iron-nitrogen compound phase is used as the hard magnetic phase and an iron phase is used as the soft magnetic phase.