JPH0443613A - Manufacture of magnet roll - Google Patents

Abstract

PURPOSE:To reduce the irregularity of magnetic force in the longitudinal direction and of arrangement angle of a magnetic pole, and improve productivity, by inserting a shaft while expanding a cylindrical magnet with compressed gas, and bonding and fixing the shaft from the rear. CONSTITUTION:A magnet roll A is constituted by inserting a shaft 2 made of metal or plastic into a cylindrical magnet 1 made of bonded magnet. When said magnet roll A is manufacture, a plurality of grooves 3 whose depth is set to be 0.2-0.6 mm are formed on the inner surface of the cylindrical magnet 1, in the longitudinal direction thereof. Compressed gas 4 is introduced from one end of the magnet; while the inner diameter of the magnet 1 is expanded by the effect of pressure, the shaft 2 is inserted from the other end; bonding agent 5 whose viscosity is 2-300 CPS is made to flow in the grooves 3 of the magnet by vacuum sucking; the adhesive agent 5 is uniformly dispersed all over the whole length of the groove; the magnet 1 and the shaft 2 are bonded and fixed. Thereby productivity can be improved without increasing working precision.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnet roll, and more specifically, the present invention relates to a method for manufacturing a magnet roll, and more specifically, it has excellent mechanical strength and has small variations in the arrangement angle of magnetic poles and small variations in magnetic properties in the longitudinal direction. The present invention also relates to a method for manufacturing a magnetic roll with high productivity.

[Conventional technology]

Conventionally, as a manufacturing method of this kind of magnet roll, for example, ■ two or more magnet pieces a' as shown in FIG.
, a'... to the shaft b to make it into a magnetic roll. ■ As shown in Figure 8, the shirt b) is tightly fitted into the cylindrical magnet a formed into a cylindrical shape and integrated. Methods such as (1) integral molding including the shaft have been put into practical use.

[Problem to be solved by the invention]

However, with the method of gluing the magnet pieces in ■,
When there are four or more poles, it becomes complicated to manage the magnetic properties, shape, etc. of the magnet pieces used, as well as the bonding conditions, and there are many problems in terms of quality and productivity, such as the magnitude of magnetic force and the arrangement angle of the magnetic poles. In addition, when inserting a shaft into the cylindrical magnet shown in (■), there will be variations in the magnetic properties in the longitudinal direction due to variations in the magnet's inner diameter and the shaft's outer diameter, and variations in the adhesive strength between the magnet and the shaft, resulting in unstable quality. Zu, again,
In order to stabilize quality, the only option was to increase processing accuracy, which resulted in cost problems. Also, since shaft b needs to fit tightly into magnet a,
There is a problem that the shaft scrapes the inner wall of the cylindrical magnet when the magnet is tightly fitted, resulting in the generation of scraps, and there is also the problem of disposing of the adhesive that oozes out when the magnet is tightly fitted. In the case of integral molding including the shaft by injection molding, the molding die is complicated and expensive, and the magnetic force in the long plane direction varies due to variations in cooling conditions. In addition, since an expensive magnet material is used as the shaft material, it is uneconomical.

[Means to solve the problem]

In view of the above circumstances, the present inventors conducted intensive research to solve the above problems, and as a result, they arrived at the present invention.

That is, in manufacturing a magnet roll composed of a cylindrical magnet made of a bonded magnet and a shaft, the present invention has a method in which the inner diameter of the cylindrical magnet is set to have a depth of 0.2 to 0.6 m. A plurality of grooves are provided in the longitudinal direction of the cylindrical magnet, compressed gas is introduced from one end of the magnet, the inner diameter of the magnet is expanded and expanded by the pressure, and a shaft is inserted from the other end. , While applying vacuum from the other end, attach the magnet:
- A method for manufacturing a magnet nodrol, characterized in that the cylindrical magnet and the shaft are adhesively fixed by flowing an adhesive with a viscosity of 2 to 300 CPS into the groove and uniformly dispersing the adhesive over the entire length of the groove. That is. Any compressed gas may be used as long as it does not react with the metal or bonded magnet, but it is preferable to use air from the viewpoints of workability and economy.

[Effect]

After the cylindrical magnet is cut to a predetermined length, one end
That is, the shaft is inserted while expanding the inner diameter of the cylindrical magnet by introducing compressed gas from the side opposite to the side where the shaft is inserted.

After the shaft has been inserted as described above, when the introduction of compressed gas is stopped, the cylindrical magnet, which had been expanded by the compressed gas, contracts and is fixed to the shaft.

Next, while vacuum suction is applied to one end between the cylindrical magnet and the shaft, adhesive is introduced from the other end, and the adhesive is guided into the groove to firmly fix the cylindrical magnet and the shaft.

The cylindrical magnet to which the shaft is adhesively fixed is subjected to a predetermined magnetization to form a magnet roll. The magnet roll obtained by the present invention is suitably used as a developing and cleaning magnet roll for use in electrophotography in copying machines, printers, facsimile machines, and the like.

〔Example〕

Next, details of the present invention will be explained based on illustrated embodiments.

FIG. 1 shows an example of a magnet roll manufactured by the manufacturing method of the present invention. The magnet roll A is constructed by inserting a shaft 2 made of metal or plastic into a cylindrical magnet 1 made of bonded magnet. A plurality of grooves 3 are provided on the inner diameter surface of the cylindrical magnet 1 along the longitudinal direction of the cylindrical magnet 1.

Regarding the material of the bonded magnet, first, known synthetic resins and rubbers can be used as the binding material, such as thermoplastic resins such as polyvinyl chloride, polyethylene, polybrohylene, chlorinated polyethylene, ethylene/vinyl acetate copolymer, NBR, etc. , SBR, etc. are used alone or in a mixture of two or more, and as magnetic powder, for example, ferrite type such as magnetobrambite type Sr or Ba ferrite, Sw+ -Co type alloy, Nd-Fe-B, etc. A rare earth type material, 12Ni-Co type, etc. are used. The content of magnetic powder is preferably 30 to 70% by volume. It is also possible to add a silane treatment agent, a titanate treatment agent, a plasticizer, and other commonly used additives to improve the affinity and fluidity between the magnetic powder and the binder.

The bonded magnet preferably has a maximum energy product of 1.5 mega Gauss Oersted (hereinafter referred to as MGOe) or more. This is because if it is less than 1.5 MGOe, it is difficult to obtain the normally required surface magnetic flux density of the magnet roll of 900 Gauss (hereinafter Gauss is referred to as G).

The shaft used in the present invention is made of a metal such as iron or aluminum, or a so-called engineering plastic such as bophenylene oxide or polyamide.

The cylindrical bonded magnet used in the present invention is
It can be easily obtained by magnetically oriented extrusion molding of the above composition.

The depth d of the groove 3 carved on the inner diameter surface of the cylindrical magnet is preferably about 0.2 to 0.06 mm, more preferably about 0.3 to 0.5 mm. If it is smaller than 0.2+++m, the adhesive will not flow in sufficiently and will not be distributed uniformly. On the other hand, if it is larger than 0.6 mm, the adhesive will be attracted to the suction side by the suction force, causing contamination of the shaft and a decrease in adhesive strength. The number of grooves depends on the inner diameter of the cylindrical magnet, but for shaft diameters of 5 to 81 mm, there are 2 or more grooves, and 4 grooves.
~8 pieces is suitable.

If the number of grooves is one, the adhesive strength will be weak and the shaft will not be sufficiently fixed. Moreover, if there are more than 10 grooves, there will be too many grooves on the inner diameter surface, which will make it difficult to achieve coaxiality between the cylindrical magnet and the shaft, and the bonding area to the shaft will decrease, resulting in a decrease in bonding strength.

Adhesives are cyanoacrylate and epoxy.

In addition, anaerobic adhesives such as tetraethylene glycol dimethacrylate can be used, but cyanoacrylate adhesives with a viscosity of 2 to 300 CPS are preferred from the viewpoint of handling PZ workability.

When the viscosity exceeds 300 CPS, it takes time to inflow by suction or it becomes difficult to inflow, and it becomes difficult to uniformly distribute the adhesive over the entire length. Furthermore, if the viscosity is too low, it will be difficult to control adhesion, and care must be taken to avoid contamination of the shaft due to adhesive overflow.

FIGS. 4(A) and 4(B) are explanatory diagrams showing a method of attaching the shaft 2 to the cylindrical magnet 1. A cylindrical magnet 1 having a predetermined shape is obtained by cutting a continuous long cylindrical magnet with a plurality of grooves 3 carved into a predetermined length into a predetermined length.
After creating the cylindrical magnet 1, one end of the cylindrical magnet 1, that is,
Compressed gas 4 is introduced from the side opposite to the side where the shaft 2 is inserted, and the shaft 2 is inserted while expanding the inner diameter of the cylindrical magnet 1. As the compressed gas, an inert gas such as air or nitrogen is used, but air is particularly preferred, and its pressure is preferably about 3 to 5 kg/cm. pressure is 2 kg
If it is smaller than /cfll, although it depends on the material of the magnet, the expansion and expansion of the cylindrical magnet throat 1 by the compressed gas will be insufficient, making it difficult to insert the shaft 2.

On the other hand, if the weight exceeds 5 kg/cni, it becomes difficult to control the expansion of the cylindrical magnet.

After the shaft 2 is inserted as described above, the compressed gas 4
When the introduction of the compressed gas 4 is stopped, the cylindrical magnet 1, which had been expanded by the compressed gas 4, contracts and is fixed to the shaft 2.

Next, as shown in FIG. 4(b), one end between the cylindrical magnet 1 and the shaft 2 is vacuum-suctioned, and the adhesive 5 is applied from the other end.
The adhesive 5 is guided into the groove 3 by the vacuum suction force, and the cylindrical mag fund 1 and the noyaft 2 are firmly adhesively fixed. The adhesive 5 is quickly introduced into the groove 3 due to the vacuum suction, and the adhesive 5 is evenly distributed over the entire length of the groove.

The cylindrical magnet to which the shaft is adhesively fixed is subjected to a predetermined magnetization to form a magnet roll.

Hereinafter, the tests conducted to verify the results of the present invention will be explained in more detail with reference to comparative examples, but the present invention is not limited by these in any way.

μ'' (1) A pellet of a magnetic resin composition consisting of 65% by volume of strontium ferrite and 35% by volume of soft vinyl chloride resin is extruded using an extruder (manufactured by Ikegai Iron Works, 65 mm, I, /D = 2
2), a cylindrical magnet having an outer diameter of 13.6φ and an inner diameter of 5.4φ was created by magnetic field orientation extrusion molding.
Based on this cylindrical magnet, various four-pole cylindrical magnets were created with varying numbers of grooves and groove depths. Next, the shaft was inserted into each of the cylindrical magnets created in this way while introducing 4 kg/aft of compressed air from the side opposite to where the shaft was inserted, and then a vacuum suction force of 350 mmHg or less was applied from the compressed air introduction side. While suctioning the groove between the cylindrical magnet and the shaft with the suction device that can be achieved,
Cyanoacrylate adhesive with a viscosity of 40 CPS (Aron Alpha #24 manufactured by Toagosei Chemical Co., Ltd.) was applied to the groove on the shaft insertion side.
1) was introduced and the shaft was fixed with adhesive. For each of the magnet rolls thus produced, the outer surface of the cylindrical magnet was fixed with a holder, and then a tensile force in the axial direction was applied to the shaft, and the shaft fixing force was measured. In the test, 10 magnetic rolls were created for each type, and the average value was calculated. The results are shown in Table 1.

Similarly, the number of grooves is 4, the groove depth is 0.2 mm, and the groove depth is 0.4 nu.
After inserting the shaft into a cylindrical magnet with +i, 0°6mm, and 0.8mm, the viscosity becomes 2 and 4, respectively.
0.100, 200.

A cyanoacrylate adhesive (Aron Alpha manufactured by Toagosei Chemical Co., Ltd.) of 300, 500, and 800 CPS was introduced and fixed, and the fixing force of the shaft was measured when the viscosity was changed. The results are shown in Table 2. In addition, a comparative magnet roll was prepared by flowing and solidifying an adhesive with a relatively low viscosity without using a suction device under the same other conditions, and the shaft fixing force of this magnet roll was measured. For the measurement, 10 pieces of each magnetic roll were created, and the average value was calculated. The results are shown in Table 3.

As is clear from Table 1.2.3, the groove depth is 0.2~
0.6+n+a, the number of grooves is 4 to 8, and the viscosity of the adhesive is 2 to 300 CPS, it was found that the adhesive flows smoothly and sufficient adhesive fixing force can be obtained. As shown in Table 3, although it is possible for the adhesive to flow in without vacuum suction, it takes a long time for the adhesive to completely flow into the entire length of the groove, which poses a problem in productivity. It was also found that it was not suitable for mass production.

Table 1 Table 2 Table 3 Number of grooves created in Test 1: 4, groove depth 0.4-m,
An adhesive with a viscosity of 40 CPS was post-magnetized to create a 4-pole magnetic roller with the magnetic pole arrangement shown in Figure 5, and the variations in surface magnetic flux density and longitudinal magnetic flux density as well as the magnetic pole arrangement angle were determined. The variation was measured. In addition, for comparison, the surface magnetic flux density, the fluctuation in the longitudinal magnetic flux density, and the fluctuation in the arrangement angle of the magnetic poles of two types of magnet rolls made by the conventional manufacturing method were also measured at the same time. As shown in Fig. 6, conventional method 1 employs four magnet pieces adhered to the shaft using adhesive, and conventional method 2 employs a shaft tightly attached to a cylindrical magnet without grooves. I adopted the one that was fitted. For the measurement, 10 pieces of each magnetic roll were created, and the average value was calculated. The results are shown in Table 4.

Table 4 As is clear from Table 4, compared to Conventional Method 1 and Conventional Method 2, the magnetic roll obtained by the present invention has smaller variations in magnetic force in the longitudinal direction, and also has smaller variations in the arrangement angle of the magnetic poles. I understand.

The reason why there are many variations in magnetic properties in the magnet rolls made by Conventional Method 1 is that because multiple separate magnet pieces are used, it is difficult to match the magnetic properties of each of these magnet pieces, and the joints are difficult to match. This is because it is difficult to make the magnetic field distribution a predetermined distribution in This is presumably because variations in the machining accuracy of the outer surface of the shaft and the inner diameter surface of the cylindrical magneto h are directly reflected as variations in the magnetic properties, and moreover, the shaft cuts the inner diameter surface of the cylindrical magnet during close fitting. In contrast, in the manufacturing method of the present invention, since the cylindrical magnet is integrated, the magnetic field distribution can be easily controlled, and the cylindrical magnet and the shaft are fixed by a sufficient amount of adhesive supplied through the groove. As a result, there is no need to forcibly push the shaft into the cylindrical magnet in a tight-fitting state as in conventional method 2, and as a result, even if the machining accuracy of the shaft outer surface or the inner diameter surface of the cylindrical magnet is slightly inferior, This variation is not directly reflected as variation in the magnetic properties, and furthermore, since the shaft does not cut the inner diameter surface of the cylindrical magnet, the magnetic properties are not adversely affected.

(Effects of the Invention) As the soft soil suggests, according to the present invention, it is possible to provide a high-quality magnet roll that is excellent in mechanical strength and has small variations in both the longitudinal direction of the magnetic force and the variation in the arrangement angle of the magnetic poles. In the present invention, the shaft is inserted while expanding the cylindrical magnet using compressed gas, and is then fixed with adhesive.Therefore, there is no problem with edge processing due to cutting chips or adhesive extrusion as in conventional methods, and production is easier. In addition, since the shaft and cylindrical magnet are securely fixed with a sufficient amount of adhesive supplied through the groove, the machining accuracy of the shaft external surface and the cylindrical magnet internal surface is improved. does not need to be sophisticated,
Productivity can be further increased.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of one embodiment of a magnet roll produced by the manufacturing method of the present invention, Fig. 2 is a front view of a cylindrical magnet used in the same embodiment, and Fig. 3 is a portion of the same cylindrical magnet. An enlarged explanatory view, FIGS. 4(a) and 4(b) are explanatory views showing the method of inserting the shaft into the cylindrical magnet, and FIG. 5 is a front view of the magnet roll of the present invention used in two tests. Figures 6 and 7 are front views of the magnet roll manufactured by the conventional method used in Test 2;
FIGS. 8 and 9 are explanatory diagrams of conventional magnet rolls. A: Magnet roll, 1: Cylindrical magnet, 2: Shaft, 3: Groove, 4: Compressed gas, 5: Adhesive, a: Cylindrical magnet, magnet piece, b: Shaft. Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures Figures

Claims (1)

[Claims] 1) When manufacturing a magnet roll composed of a cylindrical magnet made of bonded magnet and a shaft, the depth in the longitudinal direction of the inner diameter surface of the cylindrical magnet is 0.2 to 0.6 mm. At the same time, compressed gas is introduced from one end of the cylindrical magnet, and the shaft is inserted from the other end while expanding and expanding the inner diameter of the magnet due to the pressure, and then the shaft is inserted from the other end. The magnet and shaft are bonded together by flowing an adhesive with a viscosity of 2 to 300 CPS along the groove and sucking it from the other end, distributing the adhesive uniformly over the entire length of the groove. A method for manufacturing a magnetic roll. 2) Claim 1 in which the shaft is made of metal or plastic.
The method for manufacturing the magnetic roll described. 3) The method for manufacturing a magnet roll according to claim 1 or 2, wherein the compressed gas is air. 4) Claims 1 to 4 in which the cylindrical bonded magnet has a maximum energy product of 1.5 mega Gauss Oersted or more.
The method for manufacturing a magnetic roll according to claim 3. 5) Claims 1 to 5 in which the adhesive is made of cyanoacrylate.
The method for manufacturing a magnetic roll according to claim 4.