JPH06140249A - Orientation and/or magnetization device for magnet roll - Google Patents

Abstract

PURPOSE:To cope with the change of the desired magnetic characteristics and the change of type of a magnet roll using a common orientation device and a magnetizing device. CONSTITUTION:An orientation and/or magnetization device is radially arranged directing to the center of a retaining drum 54, and also it is provided in a detachable manner independent of the inner circumferential surface of the retaining drum 54 and also in a movable manner in the direction of circumference. A plurality of magnets 56, with which the prescribed magnetic field is worked on the objective substance 32 to be arranged in the center part of the drum 54, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an orienting device and / or a magnet molding for orienting the easy axis of magnetization of magnetic powder in a certain direction when molding a magnet roll used as a developing roll of an electrophotographic copying machine. The present invention relates to a magnetizing device for magnetizing.

[0002]

2. Description of the Related Art In the case of an electrophotographic copying machine, FIG.
As shown in FIG. 5, the original image read through the optical system and the optical image of information converted into an electric signal are exposed on the photosensitive drum 100 to form an electrostatic latent image on the surface of the drum 100, and the toner is exposed in the developing device 102. The electrostatic latent image on the drum 100 is adhered (developed), transferred onto the sheet 104, and then fixed on the upper fixing device 106.

FIG. 13B is an enlarged view of a main part of a developing device 102 using a magnet roll 108 having five magnetic poles. The magnet roll 108 is fixed in position and the sleeve 110 is rotatable. It is provided. The toner attached to the surface of the sleeve 110 by the magnetic force of the magnet roll 108 is conveyed through each magnetic pole of the magnet roll 108 as the sleeve 110 rotates, and is attached to the surface of the photosensitive drum 100 by electrostatic attraction at the developing point.

Conventionally known as this type of magnet roll are a sintered magnet formed by sintering ferrite powder and the like, and a plastic magnet formed by molding ferrite powder and the like together with a resin binder.

The former sintered magnet can be obtained by pressing magnetic powder in a magnetic field to sinter and magnetize it. However, this magnet has a large dimensional change in the sintering process and has a desired outer diameter. Therefore, there is a problem that processing such as grinding is required in a later step, and cracks and chips easily occur and handling is difficult.

On the other hand, the latter plastic magnet has better manufacturability than the sintered magnet and has an advantage that chipping, cracking and the like are less likely to occur. This plastic magnet is generally manufactured by kneading a mixture containing magnetic powder and a resin binder and injection molding the mixture in a mold.

When a kneaded material (magnet material) of magnetic powder and resin binder is injected into a mold for molding, a magnetic field is applied to the cavity of the mold so that the easy axes of magnetization of the magnetic powder are aligned in a certain direction. Although injection molding is performed in a state of being applied, it is important to increase the degree of orientation of magnetic powder during injection molding in order to improve magnet performance because the resin binder intervenes between magnetic powder in plastic magnets. Is.

As a manufacturing apparatus for this type of magnet roll, a conventional one as shown in FIG. 14 is known (Japanese Patent Laid-Open No. 60-202912). As shown, the device 116 includes a plurality of yokes 118, 1 of soft magnetic material.
20, permanent magnet 122, spacer 12 made of non-magnetic material
4 and the like are integrated to form a cavity 11 for roll forming.
The mold having 4 and the orienting device are integrally configured,
When the magnet material is filled in the cavity, the easy axis of magnetization of the magnetic powder is oriented in a specific direction by an orienting device including the permanent magnet 122 so that desired magnetic characteristics are exhibited.

[0009]

However, in the case where the die and the orienting device are integrated as described above, a die-orienting device that responds whenever the required magnetic characteristics of the magnet roll, product type, etc. are changed is required. There's a problem.

In actual manufacturing, the mold-orientation apparatus as a whole must be replaced every time the required magnetic characteristics and quality change, so that there is a problem that a great deal of labor and time is required for the setup change. .

[0011]

The device of the present invention has been devised to solve such a problem, and its gist is to arrange a holding drum and a radial arrangement toward the center of the holding drum. And a plurality of magnets that are independently detachable and movable in the circumferential direction on the inner peripheral surface of the holding drum and that apply a predetermined magnetic field to an object arranged in the center of the holding drum. It is in.

[0012]

As described above, according to the present invention, the orienting device or the magnetizing device is provided in an independent form, and the magnets are radially arranged so as to surround the object, and they are independently used as the holding drum. It is detachable and movable in the circumferential direction.

When the present invention is applied to an aligning device, various magnetic characteristics can be imparted to the magnet roll under a common mold and a common aligning device. This is because it is possible to move each magnet of the orientation device around the object, increase or decrease the number of the magnets, or change the strength of each magnet freely.

As described above, the orienting device of the present invention can respond to a change in required magnetic characteristics by changing the position, number, strength, etc. of the magnets, and therefore magnets having different magnetic characteristics. When manufacturing rolls, the time and effort required for setup change can be significantly reduced.

The present invention can also be applied as a magnetizing device for magnetizing a magnet molding, and even in this case, the magnetizing pattern can be variously changed by the same device. You can

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 8 shows an example of a plastic magnet roll, and the plastic magnet roll 10 of this example has a small diameter and a long length (for example, the magnet surface is 1
8 mmφ x 310 mm) with a shaft 1 in the center
2 are integrally provided. A flat engagement surface 14 for alignment is formed on the shaft 12.

FIG. 1 shows an apparatus for manufacturing this magnet roll 10, and 16 is an injection apparatus for injecting a kneaded material of a magnet material from a tip nozzle of a cylinder 18. Reference numeral 20 denotes a molding apparatus having a vertically oriented pressure cylinder 22. Two
Reference numeral 4 denotes an orienting device for orienting the magnetic powder so that the easy axis of magnetization of the magnetic powder coincides with the direction of the magnetic force line of the magnet roll 10 during injection molding of the fluidized magnet material.

The orienting device 24 is a lower plate 2 of the molding device 20.
It is supported on 6 and can be moved leftward in the figure from the molding position together with the lower plate 26. Then, the molding die 28 that has moved together with the orienting device 24 at the moving destination, that is, at the take-out position is ejected and is ejected to the outside by the ejection operation of the cylinder 30.

The essential parts of the molding die 28 and the molding device 20 are shown in detail in FIG. As shown in the figure, the molding die 28 is a thin-walled (thickness of about 3.5 mm) pipe-shaped main die 32 having a circular cross section and made of a highly rigid and non-magnetic material.
And a pair of end molds 34 for closing the openings at the upper and lower ends thereof,
It consists of 36 and.

On the other hand, the molding apparatus 20 has a lower plate 26 and an upper plate 37 which are arranged so as to face each other vertically, and the upper plate 37 is vertically driven by the pressure cylinder 22. Has become. A receiving block 38 is provided on the lower plate 26 of the molding apparatus 20, and the receiving block 38
A holding cylinder 40 is provided on the bottom of the molding die 28 by the receiving block 38 and the holding cylinder 40 (see FIG. 9).
). Reference numeral 44 is a projecting pin for projecting the molding die 28 from the holding cylinder 40 and the receiving block 38.

The upper plate 37 has passages 46 and 48 for guiding the plastic magnet material ejected from the ejection cylinder 18, and the ejection head 5 for ejecting the passages downward.
0 and are provided. The discharge head 50 discharges the magnet material into the molding die 28 with its own opening aligned with the opening of the end die 36 of the molding die 28. The openings of the ejection head 50 and the end die 36 are aligned by the guide 52 fitted to the forming die 28.

The structure of the orienting device 24 is shown in FIGS. In these figures, 54 is a holding drum fixed to the lower plate 26 by a fixture 55 at the lower end, and a plurality of magnets (electromagnets) 56 radially arranged on the inner peripheral surface are movable in the circumferential direction of the drum 54. Is attached to. In this example, the total number of magnets 56 is 6 (6 poles).
Although provided, the number is not limited.

As shown in the enlarged view of FIG. 6, the magnet 56 includes a main body yoke 60, an inner peripheral end yoke 62, and a coil 66 wound around the yoke via a cylindrical holding member 64.
And is attached to the drum 54 by a bolt 70 on the base end side (outer peripheral end side) via a mounting plate 68.

In each electromagnet 56, a main body yoke 60 and an end yoke 62 are fastened to each other with long bolts 72, and the main body yoke 60 is fixed to a mounting plate 68 with bolts 76. Further, the coil 66 and the holding member 6
No. 4 is prevented from coming off from the yoke by a stopper 74.

That is, in the case of this example, as shown in FIG. 7A, each electromagnet 56 can be disassembled and can be assembled into each part constituting them. Therefore, if any part is damaged, it is possible to replace only the damaged part without replacing the entire electromagnet 56. Alternatively, there is an advantage that only the end yoke 62 can be replaced if necessary.

Of course, it is also possible to remove one electromagnet 56 as a whole. In this case, as shown in FIG. 7 (B), the suspending tool 86 is fixed to the mounting plate 68 of the electromagnet 56 and the main body yoke 60 and then removed. It is made possible.

As shown in FIG. 3, elongated holes 78 and 80 extending in the circumferential direction are formed in the drum 54.
A bolt 70 for fastening and a knob 82 for rotating the electromagnet 56 penetrate through these elongated holes 78, 80 and project outward.

In the orienting device of this example, these long holes 7
By moving the bolts 70 along 8, the positions of the electromagnets 56 can be changed in the circumferential direction of the drum 54. In response to this, a scale 84 is provided on the upper end surface of the drum 54.

Incidentally, as shown in FIG. 6, the end yoke 6
In part 2, the inner peripheral side part (tip working part) 62a is formed shorter than the other part, and the upper and lower ends are formed in an inverse taper shape. The direction of the taper may be either forward or reverse, but the reverse taper is preferable because the quality of the molded product is good.

Next, the operation of the apparatus of this example will be specifically described. Set the molding die 28 at a predetermined position of the molding device 20,
When the magnet material is ejected from the injection device 16 with the upper plate 37 lowered, the magnetic material is ejected from the ejection head 5 of the upper plate 37.
It is discharged from 0 and flows into the cavity of the molding die 28.

At this time, the coils 66 of the electromagnets 56 of the orienting device 24 are kept energized, that is, the electromagnets 5
By applying a magnetic field in the cavity of the molding die 28 by 6, the easy axis of magnetization of the magnetic powder in the magnet material can be oriented in a specific direction.

When a magnet material having low fluidity in the low temperature range is used, it is necessary to keep the mold 28 in a heated state. However, in the case of a magnet material having good fluidity in the low temperature range. The magnet material can be satisfactorily flown and filled in the cavity without heating the molding die 28, and the easy axis of magnetization of the magnetic powder can be favorably oriented.

As such a magnet material, a material using a low melting point ethylene ethyl acrylate copolymer resin (EEA), a low density polyethylene resin or the like as a resin binder can be exemplified. By the way, the proper compounding quantity is magnetic powder 85-93.
The resin binder is 14.5 to 5% by weight and the other auxiliary materials are 0.5 to 2% by weight based on the weight%. The more preferable blending amount in the magnetic powder is 89 to 91% by weight.

It is to be noted that such a magnet material has a large molding shrinkage ratio, and therefore, it is easy to remove the mold after molding, and there is an advantage that it is not necessary to provide the molding die 28 with a draft.

After the magnet material is filled in the cavity of the molding die 28, the upper plate 37 is then raised and the molding die 28 is moved leftward in FIG.
Then, at the moving destination (take-out position), the projecting cylinder 30 is operated, the molding die 28 is lifted by the projecting pin 44, and this is taken out to the outside. And the molding device 20
Outside the orienting device 24, the magnet material is cooled and solidified and the molded product is demolded.

On the other hand, when the molded product is taken out, a separate molding die 28 is set and returned to the molding position together with the orienting device 24, so that another magnet roll 10 is continued.
Can be molded.

Therefore, according to this example, the magnet roll 1
The occupying time of the molding device 20 per piece can be significantly reduced, the molding cycle time can be significantly shortened, and the productivity can be effectively increased.

In the orienting device 24, each electromagnet 56 is held inward by the holding drum 54 and is positionally movable in the circumferential direction. Therefore, the orienting device 24 is moved in accordance with the magnetic characteristics to be given to the magnet roll 10. By moving the magnets, or by changing the strength of the electromagnets 56, or by increasing or decreasing the number of the electromagnets 56, it is possible to manufacture the magnet rolls 10 having various characteristics.

That is, according to the aligning device 24, when the shapes are the same, the single aligning device 2 is provided under the single mold 28.
4 can manufacture the magnet roll 10 having various characteristics.

Further, even when the shape of the magnet roll 10 is different, it is possible to meet the magnetic characteristics required by the single orienting device 24. That is, this orienting device 24
According to this, when manufacturing the magnet roll 10 having different magnetic characteristics, it is possible to deal with it by simply changing the position, the number, etc. of the electromagnets 56, and it is possible to obtain an advantage that the setup change time can be greatly reduced when changing the product type.

In the orienting device 24, the upper and lower ends of the part 62a of the end yoke 62 are inversely tapered. This has the following meanings.

As shown in FIG. 11A, in a bar magnet in which the density and orientation of magnetic powder are uniform, a so-called edge effect occurs in which the magnetic flux density at both ends is high. It is desirable that the magnetic roll has a uniform magnetic flux density over the entire length in the longitudinal direction, and it is not preferable that such an edge effect appears.

As a measure for reducing the edge effect, for example, as shown in FIG. 11 (B), the end portion is shaved and the diameter of the end portion is made smaller than that of the central portion to secure the uniformity of the magnetic flux density. It is possible (Japanese Patent Publication No. 4-95252). However, in this case, an end cutting process is required.

Therefore, in this example, the upper and lower end portions of the part 62a of the end yoke 62 in the orienting device are inversely tapered, and as a result, as shown in FIG. The degree of orientation of the powder can be intentionally weakened, and thus a uniform magnetic flux density can be obtained over the entire length in the longitudinal direction of the roll.

At this time, the optimum taper angle α (see (D)) varies depending on the shape of the magnet roll and the magnetic pattern, but in the case of a reverse taper, α = 20 ° to 70 °.
When the end yoke 62 has a positive taper shape as shown in FIG. 10, α = 110 ° to 160 ° is a suitable range.

This orienting device 24 is used for the magnet roll 1
When the thickness of 0 changes, it can be dealt with by changing the wall thickness of the pipe-shaped main mold 32 of the molding die 28. However, as shown in FIG. 12, the electromagnet 56 is moved in the radial direction. By allowing the magnet roll 10 to move forward and backward, it is possible to easily cope with a change in the thickness of the magnet roll 10.

In the illustrated example, the electromagnet 56 is provided so as to be movable in the radial direction by the slider 88, while it is driven in the radial direction by the action of the advancing / retreating cylinder 90 and the cam mechanism 92.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, the present invention is of course applicable to the manufacture of a magnet roll having a number of poles other than five, and is also applicable to the case where it is necessary to heat / cool the mold during molding.

Other than the above, the present invention can be implemented and configured in various forms and modes based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is an overall view of a magnet roll manufacturing apparatus including an orienting device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a main configuration of a molding die and a molding apparatus in FIG.

3 is a perspective view of the orienting device in FIG. 1. FIG.

FIG. 4 is a diagram showing a planar configuration and a side configuration of the same orienting device.

FIG. 5 is a plan view of a main part of the same orienting device.

FIG. 6 is a side view of the main part of the same orienting device.

FIG. 7 is a diagram showing a structural feature of a main part of the same orienting device.

FIG. 8 is a diagram showing an example of a magnet roll to which the present invention is applied.

FIG. 9 is an explanatory view of the operation of the main part of FIG.

FIG. 10 is a diagram of another embodiment of the present invention.

FIG. 11 is an explanatory diagram for explaining a shape effect of a yoke end portion.

FIG. 12 is a diagram of another embodiment of the present invention.

FIG. 13 is an explanatory diagram for explaining the background of the present invention.

FIG. 14 is an explanatory diagram for explaining the background of the present invention.

[Explanation of symbols]

 10 Magnet Roll 16 Injection Device 18 Cylinder 20 Molding Device 24 Orientation Device 28 Mold 30 Protruding Cylinder 32 Main Mold 34,36 End Mold 44 Protruding Pin 54 Holding Drum 56 Electromagnet 70 Bolt 78,80 Long Hole

Claims (1)

[Claims] 1. A holding drum, which is radially arranged toward the center of the holding drum and is detachably attached to the inner peripheral surface of the holding drum and movable in the circumferential direction, and the central portion of the holding drum. A magnet roll orienting and / or magnetizing device having a plurality of magnets for causing a predetermined magnetic field to act on an object arranged in the.