JP3183002B2 - Drying method for long cylindrical extruded product - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drying a long cylindrical extruded product comprising a kneaded product obtained by kneading a powder material and a liquid binder and formed through an extruding means. In particular, a long cylindrical extruded product having an outer diameter dimension D, an axial length dimension L, L ≧ 3D, and having a circular cross-sectional outer contour can be efficiently produced without bending and warping. To a drying method.

[0002]

2. Description of the Related Art Many magnet rolls conventionally used as a developing roll or a cleaning roll in electrophotography, electrostatic recording, and the like have a structure as shown in FIG. In FIG. 3, reference numeral 1 denotes a permanent magnet member, which is integrally formed in a hollow cylindrical shape with a sintered powder magnet material such as hard ferrite, or integrally formed in a cylindrical shape with a mixture of a ferromagnetic material and a binder. The shaft 2 whose both ends are reduced in diameter is coaxially fixed to the portion.

A plurality of magnetic poles (not shown) extending in the axial direction are provided on the outer peripheral surface of the permanent magnet member 1. Next, shaft 2
Flanges 3 and 4 are rotatably mounted at both ends thereof via bearings 5 and 5, and a sleeve 6 formed in a hollow cylindrical shape is fitted to the flanges 3 and 4. The flanges 3 and 4 and the sleeve 6 are formed of a non-magnetic material such as an aluminum alloy or stainless steel. Reference numeral 7 denotes a sealing member which is fitted between the flange 3 and the shaft 2.

In the above magnet roll, the diameter (D) of the permanent magnet member 1 is 15 to 60 mm, and the length (L) is 2
In many cases, L ≧ 3D in the range of 00 to 350 mm, but in the case of a relatively large permanent magnet member 1 having a diameter of 12 mm or more, the structure shown in FIG. 3 is generally used.

With the above configuration, the relative rotation between the permanent magnet member 1 and the sleeve 6 (for example, fixing the permanent magnet member 1 and rotating the flange 4) causes the magnetic developer (for example, The magnetic brush is formed by adsorbing a one-component magnetic toner or a two-component developer composed of a toner and a magnetic carrier, and a predetermined developing operation is performed.

The permanent magnet member 1 is usually formed by powder metallurgical means in many cases, but it is particularly advantageous to use an extruding means for a long one such as L ≧ 3D.
FIG. 4 is a longitudinal sectional view of an essential part showing an example of means for extruding the permanent magnet member 1 shown in FIG. In FIG. 4, reference numeral 11 denotes an extrusion cylinder, in which a suitable heating means (not shown) is interposed and a screw 12 is coaxially incorporated. Next, 13 is a die, 14 is a core metal, and forms an extrusion die 15 having a molding space 16 having a ring-shaped cross section.
It is integrally fixed to the discharge port of the extrusion cylinder 11. Next, for example, a raw material mainly composed of Ba ferrite is extruded from an extrusion die 15 to obtain a hollow cylindrical and long raw material 17.

[0007] The material 17 is cut to a predetermined axial length and sintered at a predetermined temperature. By this sintering process, the material 17
Since the outer diameter of both ends of the material 17 slightly swells, the swelled portions of the both ends of the material 17 are cut and removed after sintering, and then the outer peripheral surface is subjected to centerless grinding to obtain a permanent magnet member 1 having a predetermined axial length (FIG. See).

Next, the raw materials constituting the permanent magnet member 1 will be described.
Describe. First, a magneto-pla with a particle size of 0.7 to 1.5 μm
Ferrite particles having MOVITE type crystal structure (MOn
Fe _TwoO_Three: M = at least one of Ba, Sr, Pb, n =
5-6) and a mixture such as water and alcohol.
The mixture is mixed in minutes to produce a mud or ointment-like raw material.
In this case, the particle size of the ferrite particles is too small
And the moldability during extrusion are reduced, while the particle size is too large
Is preferable because the density of the sintered body decreases and the magnetic properties decrease.
Not good. Therefore, the particle size is in the range of 0.7 to 1.5 μm
It is better to use

If the amount of the mixture added to the ferrite particles is too small, the viscosity of the raw material increases, the formability at the time of extrusion molding is reduced, and the density of the formed body is locally varied. In this case, a crack is generated, which is not preferable. On the other hand, if the amount of the mixed solution is too large, cracks are generated when the molded body is dried, and high density cannot be obtained during molding, which is disadvantageous. Therefore, the added amount of the mixed solution is 1 to the ferrite particles.
The content is preferably in the range of 0 to 30% by weight.

[0010] In addition, methylcellulose,
By adding an organic binder such as carboxymethyl cellulose, moldability can be improved. However, if the added amount of the organic binder is too large, cracks are generated during extrusion molding and the cracks are developed during sintering, which is not preferable. Therefore, the amount of the organic binder added to the ferrite particles is 2% by weight.
Hereinafter, the content is preferably 0.5 to 1.0% by weight.

Further, 0.1 to 3% by weight of B is added to the ferrite particles.
By adding an oxide such as ₂ O ₃ , CaO, or SiO ₂ , the density of the sintered body can be improved, and the magnetic characteristics can be improved.

[0012]

The raw material 17, which is a molded body obtained by the above extrusion molding means, is in a wet state immediately after molding, and therefore needs to be dried. Bends, cracks, etc., due to the different states of progress. For this reason, means for wrapping the material 17 with, for example, air-permeable wrapping paper and performing natural drying is adopted. However, this natural drying method requires a long time of 1 to 2 weeks to complete the drying, and has a problem that productivity is significantly reduced.

Further, since only the both ends of the material 17 are supported, there is a problem that the material 17 is bent during drying, and the straightness is reduced. In order to prevent the occurrence of such bending, it is necessary to frequently change the support position of the material 17, but it must rely on manual work.
Not only does it lower productivity, it also raises manufacturing costs.

The present invention solves the above-mentioned problems in the prior art and provides a method for drying a long cylindrical extruded product uniformly and efficiently without causing bending and warping. Aim.

[0015]

In order to achieve the above object, the present invention provides a method for drying a long cylindrical extruded product having an outer diameter D, an axial length L, and L ≧ 3D. , The elongated cylindrical extruded body is placed on two rollers which are arranged in parallel with a smaller interval than D and rotate in the same direction, respectively, 5
The technical means of drying while applying a rotation of 0 rpm was adopted.

In the present invention, the roller can be disposed so that its axis is inclined at 5 to 10 ° with respect to the horizontal plane, and one end face of the long cylindrical extruded product can be supported by a rotatable support member.

In the present invention, if the rotation speed of the elongated cylindrical extruded body is small, undesired local deformation due to the weight of the flexible extruded body occurs, which is not preferable. If the number of rotations of the body is large, it is disadvantageous because deformation due to rotation or rolling is promoted. Therefore 2
Preferably, it is 50 rpm.

In the present invention, if the axis of the roller is inclined with respect to the horizontal plane, the movement of the long cylindrical extruded product rotating or rolling on the roller in the axial direction can be prevented, but the inclination angle is too large. This is not preferable because the long cylindrical extruded body is deformed in the axial direction by its own weight.
Therefore, the inclination angle is preferably set to 5 to 10 °.

[0019]

According to the above-mentioned structure, drying can proceed uniformly and efficiently while maintaining the straightness of a long and cylindrical extruded product in a soft and wet state.

[0020]

FIG. 1 is a perspective view showing a main part of a drying apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 21 denotes rollers, which are disposed with their axes parallel to each other, and are formed so as to rotate in the same direction and at the same rotation speed. Reference numeral 22 denotes a long cylindrical extruded body, for example, having an outer diameter D, an axial length L, L ≧ 3 by an extrusion means as shown in FIG.
D. The distance d between the rollers 21 and 21 is d <D. Accordingly, the long cylindrical extruded body 22 is held on the two rollers 21 and 21 and is rolled and rotated in the direction of the arrow by the rotation of the rollers 21 and 21.

With the above configuration, the elongated cylindrical extruded body 22 is formed by two rollers 21 and 21 over the entire length in the axial direction.
It is supported above and rolls slowly. In this state, hot air is supplied to the long cylindrical extruded body 22 or microwaves or far-infrared rays are radiated.
The long cylindrical extruded body 22 can be dried uniformly without deformation, bending, warping, or the like. Further, since the elongated cylindrical extruded body 22 is uniformly supported on the two rollers 21 and 21 over the entire length in the axial direction, the elongated cylindrical extruded body 22 in a soft and wet state is formed. Unwanted local crushing and cracking due to its own weight can be prevented, and straightness can be maintained.

FIG. 2 is a front view of a main part showing a drying apparatus according to another embodiment of the present invention, and the same parts are denoted by the same reference numerals as in FIG. In FIG. 2, a frame 23 supports the rollers 21 so that their axes form an inclination angle of θ with respect to the horizontal plane. Reference numeral 24 denotes a support member that supports one end face of the long cylindrical extruded body 22,
And it is formed rotatably.

With the above configuration, the long cylindrical extruded product 22 can be supported on the two rollers 21 so as to be able to roll and rotate. 22 can be dried uniformly without deformation. Since one end face of the long cylindrical extruded body 22 is supported by the support member 24, the axial movement of the long cylindrical extruded body 22 on the roller 21 is prevented, and the long cylindrical extruded body 22 rolls at a fixed position. Can be rotated.

In this embodiment, an example of a permanent magnet member is described as a long cylindrical extruded product, but the present invention is not limited to this and can be applied to a long cylindrical extruded product made of ceramic or other inorganic material. Further, it is needless to say that the present invention can be applied to a solid cylindrical shape in addition to a hollow cylindrical shape.

[0025]

Since the present invention has the above-described configuration and operation, the following effects can be obtained. (1) Since the roller is dried while being rolled and rotated on the roller, the elongate cylindrical extruded product is free to shrink in the axial direction as the drying proceeds, and cracks and cracks can be prevented from occurring. (2) Since the long cylindrical extruded product is uniformly supported by the rollers over the entire length in the axial direction, straightness can be improved. (3) By forcibly drying with a heating medium from a heat source, drying can be completed in a shorter time than conventional natural drying means. (4) By providing a plurality of roller pairs in parallel, automation and mass production are possible, and productivity can be improved and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part showing a drying apparatus according to an embodiment of the present invention.

FIG. 2 is a front view of a main part showing a drying apparatus according to another embodiment of the present invention.

FIG. 3 is a partially omitted longitudinal sectional view showing an example of a magnet roll.

FIG. 4 is a longitudinal sectional view of an essential part showing an example of means for extruding the permanent magnet member 1 in FIG.

[Explanation of symbols]

 21 roller 22 long cylindrical extruded body

Claims (2)

(57) [Claims] 1. An outer diameter D, an axial length L, L ≧ 3.
In the method of drying a long cylindrical extruded product as D, the long cylindrical extruded product is placed on two rollers that are arranged in parallel with a smaller interval than D and rotate in the same direction. A method for drying a long cylindrical extruded product, comprising placing the substrate and drying the long cylindrical extruded product while applying a rotation of 2 to 50 rpm. 2. The roller axis is set at 5 to 10 with respect to the horizontal plane.
2. The method for drying a long cylindrical extruded product according to claim 1, wherein the one end surface of the long cylindrical extruded product is supported by a rotatable support member.