JPH11115002A - Mold for molding magnet roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always hold the position of a roll main body part with respect to a shaft part to a predetermined position while avoiding that a mold becomes inadvantageous from an aspect of cost and an apparatus is scaled up. SOLUTION: A mold for molding a magnet roll is equipped with a main mold 14 for forming a molding space filled with a molten magnet material and the slide mold 20 arranged in the molding space of the main mold 14 in a freely accessible manner and moved to a retreat side accompanied by the filling of the molding space with the molten magnet material to form the shaft part of one end of the magnet roll. Rotation stopping parts 14A, 14A for preventing the rotation of the slide mold 20 at a time of the advance and retreat of the slide mold 20 are formed to the main mold 14 along the respective longitudinal directions thereof and the guide parts 20A, 20A movable along the rotation stopping parts 14A, 14A are formed to the slide mold 20 to form the mold for molding the magnet roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet roll forming metal used for forming a magnet roll used in an electrophotographic developing device such as a copying machine, a facsimile, a printer, and a magnet roll used for other purposes. It is about type.

[0002]

2. Description of the Related Art As a mold for forming the above-mentioned magnet roll, for example, Japanese Patent Application No. Hei.
As shown in Japanese Patent No. 335643, the main mold includes a cylindrical main mold having an injection port for injecting a molten magnet material at one end, and a slide mold movably disposed in the main mold. By using a mold, it is possible to make uniform the magnetic properties in the longitudinal direction of the formed magnet roll, and to improve dimensional accuracy, warpage, and the like.

As shown in FIG. 9, the shape of the inner surface of the main mold forming the molding space is circular, and the shape of the outer surface of the slide mold 31 movable to the main mold 30 is also circular. Therefore, when the slide mold 31 moves out, the slide mold 31 unexpectedly rotates.
In some cases, the position of the roll main body with respect to the shaft of the magnet roll after molding was greatly deviated from a predetermined position.

At least one of the shaft portions formed at both ends of the magnet roll, that is, the shaft portion formed by the slide die 31, is provided with a notch for positioning or transmitting a driving force. When viewed from the end of the magnet roll, the portion has a D-shaped shape, a so-called D-cut shape. The standard (magnetic force, angle reference) of the magnet roll is determined by the positional relationship between the position of the notch and each magnetic pole position (magnetic pattern) magnetized in the roll body. However, if the slide die 31 rotates unexpectedly as described above, the position of the shaft portion of the formed magnet roll with respect to the roll body is greatly deviated from the predetermined position, and the magnetic pole positions (magnetic As a result, the position of the notch portion and the position of the notch portion change, and a non-standard magnet roll is formed.

That is, a support is provided for firmly supporting the rear end of the slide die so that the slide die does not unexpectedly rotate when the slide die is moved out. However, since the rear end of the slide die must be supported by the support, the moving direction of the slide die is not only naturally increased by the provision of the part to be supported by the slide die, but also by providing the support. This leads to a disadvantage in cost due to an increase in the number of parts and an increase in the size of the entire apparatus. In addition, since the rear end of the slide type is firmly supported, the sliding resistance of the slide type when moving in and out is large, so that the size of the slide type driving device may be increased.

[0006]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is intended to solve the problem that maintaining the position of the roll body relative to the shaft at a predetermined position is disadvantageous in terms of cost. Another advantage of the present invention is that the size of the apparatus can be increased while avoiding it at once.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a main molding die for forming a molding space filled with a molten magnet material, and a main molding die formed in the molding space of the main molding die. A magnet die formed with a retreatable slide die for moving to the retreat side to form a shaft portion at one end of the magnet roll with the filling of the molten magnet material into the molding space; A mold for preventing the slide mold from rotating when the slide mold is moved back and forth in the main mold along a longitudinal direction thereof, and The slide mold was configured to be movable in the main mold having the rotation preventing portion formed therein, and a magnet roll molding mold was manufactured. Therefore, when the slide mold is moved, it is possible to smoothly move the slide mold inside the main mold without rotating the slide mold simply by providing the detent portion formed on the main mold. A strong support can be dispensed with.

The detent is formed by a flat portion formed on the inner surface in the longitudinal direction of the main mold, and the shape of the slide die is made to match the inner surface shape of the main mold having the flat portion. Since the molding die and the slide die have a simple shape and the cross-sectional shape cuts a part of a circular shape, compared to a circular shape,
The weight of the magnet roll can be reduced.

By configuring the slide mold to be retracted by the injection pressure of the molten magnet material injected and injected, the slide mold can be retracted by the injection pressure of the molten magnet material filled in the molding space. it can. Therefore,
The driving force for performing the slide type retreat can be eliminated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a magnet roll integrated with a magnet material and a mold for forming the same will be described below. FIG. 1 shows a magnet roll formed by using the mold of the present invention. This magnet roll 1 is reduced in diameter at both ends of a roll main body 2 having an oval cross section having two flat portions 2A, 2A. The shaft portions 3 and 4 are formed so as to protrude, and the notch portion 5 for positioning or driving force transmission is formed in the shaft portion 3. The shaft portion 3 is formed in a so-called D-cut shape, and is integrally formed using a magnet material. ing. In addition, as the magnet roll 1, the roll part 2 is not a cylinder but a polygonal pillar, the other shaft part 4, the one in which the notches 5 are formed in both shaft parts 3, 4, or the magnet part 1 The present invention can be similarly applied to a case in which the center of the shaft and the center of the shafts 3 and 4 are intentionally decentered.

The magnetic material constituting the magnet roll 1 is mainly composed of a magnetic powder and a binder for binding the magnetic powder, and a silane-based or titanate-based coupling agent for strengthening the bond, A mixture of lubricants to improve fluidity, stabilizers to prevent thermal decomposition of binders, etc., and can be blended with flame retardants, reinforcing agents, etc., if necessary. System, rare earth system (SmCo system, NdFeB
System), MnAIC system, alnico system, SmFeN system, etc., and as the binder, a thermoplastic resin, a thermosetting resin, a low melting point alloy or the like can be used.

The magnet roll 1 is used as a developing roll and a cleaning roll in an electrophotographic developing device such as a copying machine, a facsimile, a printer, and the like, but can be used for other purposes.

Next, a molding die for the magnet roll 1 will be described. As shown in FIG. 2, a movable substrate 6 and a fixed substrate 7 are provided.
(Only one is shown in the figure) is formed in a predetermined arrangement, and a molding unit 9 described later is provided in each mounting space 8. A molding space in the molding unit 9 is formed by combining a fixed substrate 7 on the right side of the movable substrate 6. In a state in which each molding unit 9 is closed from an injection cylinder (not shown) via a manifold 11 in a state where
The magnet roll 1 is formed in each molding space 10 by supplying the molten magnet material to the molding space 10. The nozzle 12 of the manifold 11 is
A hot gate method that heats the molten magnet material with a heater, etc.
Alternatively, any of a cold gate method without heating may be used.

The molding unit 9 will be described with reference to FIG.
As shown in FIG. 3, a substantially cylindrical back yoke 13 made of a soft magnetic material is provided in the mounting space 8, and a sleeve-shaped main molding for molding the roll body 2 is provided at the center of the back yoke 13. A mold 14 is provided. A spacer block 1 made of a nonmagnetic material is provided in the back yoke 13.
5, the main mold 14 is the spacer block 1
5 and is fixedly held at the center of the back yoke 13. Eight cooling water passages 16 are provided in the spacer block 15.
Is formed, and the molten magnetic material filled in the molding space 10 is cooled by the cooling water flowing through the cooling water passage 16. The back yoke 13 and the main mold 1
Four sets of permanent magnets 17 and a tip yoke 18 made of a soft magnetic material are radially provided at a predetermined angle between the four, and the facing sides of the permanent magnets 17 arranged with the main mold 14 interposed therebetween have the same polarity. Is set to The back yoke 13, the permanent magnet 17, and the tip yoke 18 constitute magnetic field orienting means 19 for orienting the magnetic particles of the molten magnet material in one direction. Further, as the magnetic field orienting means 19, various existing structures such as those provided with a plurality of sets other than the four sets of the permanent magnet 17 and the tip yoke 18 and the electromagnet type excitation method can be adopted.

A slide die 20 is mounted on the main molding die 14 so as to be movable in the left-right direction with substantially no gap in the radial direction, and the right end of the slide die 20 has the left end of the magnet roll 1 including the shaft 3. Is formed. The left end of the slide die 20 extends leftward through a retaining plate 21 fixed to the left side of the movable substrate 6 and is connected to an actuator 22. The actuator 22 is composed of an air compressor that pressurizes air toward the rear surface of the slide die 20 so that the slide die 20 can be moved to the forward position shown in FIG. 4 by air pressure from the air compressor. I have. still,
In addition to using an air compressor, a hydraulic cylinder, a pneumatic cylinder, a screw screw, a rack and pinion gear, a linear motor, and the like can be used as the actuator 22. An end forming die 23 having a forming portion for forming the right end of the magnet roll 1 including the shaft portion 4 is fixed to the fixed substrate 7, and the center of the end forming die 23 is melted into the forming space 10. An injection port 24 for injecting and injecting the magnet material is formed.

As shown in FIG. 3, a pair of left and right plane portions 14A, 14A,
The outer surface of the slide mold 20 which is formed in an oval shape formed over the entire area in the longitudinal direction and which is disposed movably on the inner surface of the main mold 14 with substantially no gap,
Flat portions 20A are provided at locations corresponding to the flat portions 14A, 14A.
A, 20A is configured in an oval shape formed along the longitudinal direction, and when the slide mold 20 moves forward or backward,
The slide mold 20 is prevented from rotating with respect to the main mold 14. In other words, slide type 2
0 attempts to rotate, the two flat portions 14A, 14A
A, 20A, slide type 2
It is made to act as a detent part for preventing 0 from rotating. The flat portions 14A, 14A are
By forming the permanent magnets 17 between adjacent permanent magnets 17, that is, at a location where the magnetic pole is not formed, a change in magnetic force at a location where a magnetic pole is formed is less likely to occur. 7 (a) to 7 (d) and 8 (a),
It may be formed as shown in FIG. That is, FIG.
(A) shows a slide mold 20 having a substantially D-shaped outer shape.
1 shows a magnet roll 1 formed by a main forming die 14 (not shown) having an inner surface formed substantially in a D-shape. It is substantially D-shaped with a portion 2A.
FIGS. 7B and 7D show a slide mold 20 having an outer shape composed of four flat portions and a curved portion connecting these flat portions.
(Not shown) and a main roll 14 (not shown) having an inner surface of the same shape as the slide die 20.
The roll main body 2 has four flat portions 2A. Further, as shown in FIGS. 7 (c) and 8 (a), a magnet roll 1 having a single concave portion 2B is formed in the roll body 2, or as shown in FIG. 8 (b),
A hole 2C into which the metal shaft 25 can be fitted is formed at the center of the roll body 2, and the magnet roll 1 having a single recess 2B communicating with the hole 2C may be formed. The shape of the part 2 may be any shape. In FIG. 3, the flat portion 20A is formed at a position slightly away from the magnetic pole so as not to affect the magnetic pole. However, as shown in FIGS. 7 (a) to 7 (d), the flat portion 20A largely enters the two magnetic poles. By forming the flat portion 2A and the concave portion 2B in the state, other portions (curved portions) are formed in the vicinity of the formation.
The magnetic force is weaker than that, and the magnetic pattern can be freely changed by changing the shape. Note that FIG.
(A) shows the magnetic field strength of each pole. In the drawing, the magnetic field strength at the upper and lower poles is stronger at the upper pole, and the magnetic field strength at the left and right poles is the right pole. Is stronger.

Next, a method of manufacturing the magnet roll 1 will be described. First, as shown in FIG.
The fixed substrate 7 is combined with the right side of the main molding die 14 (shown in FIG. 2) to close the molding space 10 (shown in FIG. 2) in the main molding die 14 with the end molding die 7. , The actuator 22 is driven and the slide mold 20 is driven.
To the forward position.

Next, as shown in FIG. 5, the injection cylinder is driven to move the molten magnet material from the manifold 11 (shown in FIG. 2) into the molding space 10 (shown in FIG. 2) through the injection port 24. While the slide mold 20 is retracted to the retracted position by the injection pressure of the molten magnet material.
The inside (shown in FIG. 2) is filled with the molten magnet material. In this manner, the slide mold 20 is retracted to the retracted position by the injection pressure of the molten magnet material, so that the slide mold 2
A driving force for retreating 0 can be eliminated. When an air compressor is used as the actuator 22, if a small air pressure from the air compressor is applied to the rear surface of the slide mold 20, a braking force can be applied to the backward movement of the slide mold 20. It becomes possible to fill the space 10 (shown in FIG. 2) with the molten magnet material without gaps. However,
A braking force applying means for applying a braking force by friction or the like may be provided to apply the braking force when the slide die 20 moves backward. Further, the slide die 20 may be retracted while applying a braking force by the driving means according to the injection injection speed of the molten magnet material. Further, the slide mold 20 may be retracted by the injection pressure of the molten magnet material and the driving force of the actuator 22. At this time, the direction of the magnetic particles is aligned by the magnetic field orientation means 19 until the molten magnet material filled in the molding space 10 (shown in FIG. 2) is solidified. Actuator 22 as described above
The use of an air compressor as described above eliminates the need for the coupling work required when the slide die and the drive mechanism that drives it are mechanically interlocked in order to advance the slide die. Necessary members can be eliminated. Further, in the case of mechanical interlocking, it is possible to avoid generation of abnormal noise or difficulty in movement at the connecting portion due to long-term use or a problem with the accuracy of the connecting parts or the connecting accuracy.

Next, as shown in FIG. 6, after the molten magnet material injected and solidified is solidified, the movable mold 6 (not shown) having the main mold 14 is moved away from the fixed mold 7. After that, the actuator 22 is driven to move the slide mold 20 forward, and the magnet roll 1 is detached.

In the above embodiment, the shaft portion and the roll portion are integrally formed. However, a shaft insert type magnet roll in which a metal or synthetic resin shaft is inserted may be formed, or as shown in FIG. As shown, the present invention can also be applied to a case where a metal or synthetic resin shaft is fitted into the formed magnet roll 1. Further, in the above embodiment, the main molding die 14 is constituted by a cylindrical member, but may be constituted by two divided molds.

[0021]

According to the first aspect, when the slide mold is moved, the detent portion formed on the main mold moves and guides the guide of the slide mold, so that the slide mold is smoothly rotated without rotating. In addition to being able to be moved, a rigid support as in the related art can be dispensed with, and as a result, it is disadvantageous in terms of cost to constantly maintain the position of the shaft portion with respect to the roll body at a predetermined position. This can be realized while avoiding the problem and increase in size of the device at once.

According to the second aspect, since the main mold and the slide mold can be formed in a simple shape, the main mold and the slide mold can be easily formed. Also, as compared to a circular cross section, the formation of the flat portion eliminates a part, thereby reducing the weight of the magnet roll. By setting the place where the flat part is formed to a place that is hardly affected by the magnetic force between the magnetic poles, it is possible to apply a magnetic force to the magnet roll having a cross-sectional shape substantially equal to that of a circular shape, Is set at a location corresponding to the magnetic pole, the magnetic force at that location can be weakened to change the magnetic pattern.

According to the third aspect of the present invention, the retraction of the slide die is performed by the injection pressure of the molten magnet material filled in the molding space, so that a driving force for performing the retraction of the slide die can be made unnecessary. The operating cost can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is a perspective view of a magnet roll integrated with a magnet material.

FIG. 2 is a sectional view showing a molding unit.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is a schematic cross-sectional view of the molding unit showing a state where the slide die is located at a forward position.

FIG. 5 is a schematic cross-sectional view of a molding unit showing a state where a slide mold is positioned at a retracted position by injection of a molten magnet material.

FIG. 6 is a schematic sectional view of a forming unit showing a state where a formed magnet roll is taken out.

FIGS. 7A, 7B, 7C, and 7D are front views showing other shapes of the magnet roll.

FIG. 8A is a front view showing the shape of another magnet roll, and FIG. 8B is a cross-sectional view showing the shape of another magnet roll.

FIG. 9 is a cross-sectional view showing the shapes of a conventional main mold and a slide mold.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Magnet roll 2 Roll main body part 2A flat part 2B concave part 2C hole 3 shaft part 4 shaft part 5 notch part 6 movable substrate 7 fixed side die 8 mounting space 9 molding unit 10 molding space 11 manifold 12 nozzle 13 back yoke 14 main molding die 14A Flat part (rotation stop part) 15 Spacer block 16 Cooling water passage 17 Permanent magnet 18 Tip yoke 19 Magnetic field orienting means 20 Slide type 20A Flat part (guide part) 21 Retaining plate 22 Actuator 23 End part forming die 24 Inlet 25 Shaft 30 Main mold 31 Slide mold

Claims (3)

[Claims] 1. A main molding die for forming a molding space filled with a molten magnet material, and a main molding die is provided so as to be able to move back and forth in the molding space of the main molding die, and melts into the molding space. With the filling of the magnet material, a magnet for forming a magnet roll, comprising a slide mold for moving to the retreat side to form a shaft portion at one end of the magnet roll, and when the slide mold is retracted, A shape in which the main mold is provided with a detent portion for preventing the slide die from rotating along the longitudinal direction thereof, and is movable in the main mold in which the detent portion is formed. A mold for forming magnet rolls comprising a slide mold. 2. The slide-molding device according to claim 2, wherein the rotation preventing portion is formed by a flat portion formed on an inner surface in a longitudinal direction of the main molding die, and a shape of the slide die is matched with an inner surface shape of the main molding die having the flat portion. The mold for forming a magnet roll according to claim 1, characterized in that: 3. The magnet roll molding die according to claim 1, wherein said slide die is retracted by injection pressure of a molten magnet material injected and injected.