JPS6060669A - Magnet roll for magnetic brush development of dry type electronic copying machine - Google Patents

Abstract

PURPOSE:To form a lightweight magnet roll and obtain high characteristics by making a magnet piece of a plastic magnet and magnetizing it so that magnetic paths are formed from the external surface to both flanks. CONSTITUTION:Magnet pieces 2 fitted to the outer circumference of a roll shaft are made of plastic magnets molded by injection, and the magnet pieces 2 are magnetized so that magnetic paths are each formed so that magnetic paths are formed from the outer circumferential surface 2b to both flanks 2c in a section while the shapes and magnetization states of the magnet pieces 2 are uniform and highly precise. Consequently, the magnet roll for the magnetic brush development of a dry type electronic copying machine is lightweight and manufactured easily, and it has high characteristics, i.e., high surface magnetic flux density and uniform magnetic flux distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an improvement to a magnet roll for magnetic bluff development of a dry type electronic copying machine using a two-component developer having a -component magnetic toner or a magnetic carrier.

This type of magnet roll is required to have a uniform magnetic flux density distribution along the longitudinal direction of its outer peripheral surface and a predetermined magnitude of magnetic flux density for its purpose of use. Conventionally, in order to meet this requirement, anisotropic 1'J: 49° stones were pressed into a rectangular parallelepiped of approximately 80 to 100 wuπ] and these were connected and fixed in the longitudinal direction of the outer surface of the roll shaft. However, in the case of I/4 construction, le/1. The problem is the decline in east density. Conventionally, in order to solve this problem, various improvements have been made to the way the magnet pieces are connected and the roll structure. However, these conventional proposals have had various problems because they all use sintered magnets as magnet pieces.In other words, sintered magnets have warped during firing. Since cranks may occur during contraction, it is difficult to manufacture products with a specified shape with a high circulation rate.However, post-processing is also difficult.Therefore,
Inserting a large number of magnet pieces onto the roll shaft so that the surface magnetic flux density of the roll is uniform is relatively time-consuming and the manufacturing cost is relatively high, and the roll as a whole becomes quite heavy. There was also a drawback.

The purpose of the present invention is to take advantage of the above-mentioned circumstances and not only make it possible to manufacture even i, f''i: 11+'h K even with a quantity of 1, but also to achieve a uniform magnetic flux density distribution by combining with a high surface magnetic flux density. It is an object of the present invention to provide a magnet roll for magnetic bluff development of a dry type electronic copying machine, having the following.

According to the present invention, this object is achieved by forming a plurality of magnet pieces to be connected and fixed in the longitudinal direction of the surface of the roll shaft using plastic magnets; 11. This is achieved by magnetizing each of the 11 pieces of stone so that a magnetic path is formed from the outer surface toward both sides +1iir within its cross section.

Positioning means are provided on the outer surface of the roll shaft and on the surface of each magnet piece that abuts the roll shaft to facilitate connection and fixation of the magnet pieces to the outer surface of the roll shaft.

If the present invention is explained in detail based on the embodiment shown below, in the figure, ■ is a roll shaft preferably made of synthetic resin having a plurality of grooves 1a formed in parallel to the longitudinal direction on the outer surface of the large diameter part. , 2 is the same in the inner peripheral direction and the roll shaft 1 is common (I "T;, 1AJC can enter at least two protrusions 2 A, 2 A 1j that is a fan -shaped fan. A plastic magnet (a resin material mixed with, for example, iron oxide powder and made anisotropic during injection molding, or an injection molded material) made of a rod-shaped stone piece of an appropriate length. , No.: As illustrated in FIGS. 3 and 4, the outer surface 2 in the horizontal (1'ji plane)
From b to both sides 2c, towards 2c? It is magnetized so that i = FES is formed, and as shown in Figs. 1 and 2, in the longitudinal direction of the roll shaft 1 there are only those with the same polarity, and in the circumferential direction, the magnetic poles are alternately different. It is connected and fixed on the outer circumferential surface of the roll shaft 1 using an adhesive or the like so that it can be attached. 3 is a roll/gift 1 in which a plurality of paving stone pieces 2 are connected and fixed, and the entire roll/gift 1 is heated so as to be loosely heated. It is a sleeve made of stainless steel, aluminum, etc. that is supported so as to be rotatable concentrically with respect to the roll shaft 1 by a pair of flanges 5.5 supported on the roll shaft 1.

Since the red sea bream sotrol according to the present invention is constructed as described above, when assembling it, the polarity of the two magnet pieces prepared in advance must be considered. : Protrusion 2a on f71a
By simply arranging them together, you can simply connect and fix them. In addition, 1 formed on the roll shaft 1
Due to the shape of the roll shaft itself, iFrla can be drilled with extremely high precision, and the magnet piece 2 is manufactured by injection molding.

All the magnet pieces can be made homogeneous in both the magnetization directions and have a high degree of M'jJ, so that it is possible to obtain a magnet roll with less variation in surface magnetic flux density4.According to experiments, each magnet The decrease in flux density at the joints of the pieces is extremely small and can be ignored in practice, and the surface magnetic flux density after assembly is compared to the surface flux density of individual Itf4 stone pieces. It was confirmed that the amount increased by about 30% compared to the previous year.

In the above embodiment, a plurality of 1ω stone pieces 2 are mounted on the roll shaft l.
As a means for determining the position 1δ when installing the roll shaft 1, a protrusion 2a is formed on the magnet piece 2 on the roll shaft l-1, but it is also possible to form a protrusion on the roll shaft 1 and a groove on the magnet piece 2. In addition, the shape and arrangement of i+1j are limited to the embodiment and can be independently modified and modified.Furthermore, in the embodiment, the roll shaft is circular in the transverse direction, but this It may be a polygon,
In this case, 1. Therefore, the shape of the contact surface of the magnet piece with the roll shaft may be appropriately selected. Note that the roll shaft l (r1 has been described as one made of synthetic resin having a large diameter part, a middle diameter part, and a small diameter part, but it is also possible to use a roll shaft made of synthetic resin having a middle diameter part and a small diameter part (r1). It may also have a structure in which a pipe is fitted (press-fitted).

As described above, according to the present invention, not only can the weight of the entire magnet roll be significantly reduced, but also the magnetic flux density of the magnetic roll is large and the surface (1) of this type of magnet roll with a uniform flux density distribution is can be provided at a low price.

4. Figure 1 is a vertical view of an embodiment of the magnetic roll according to the book 5u, and Figure 2 is along the II-11 gland in Figure 1. Figure 3 is a Drii plane view showing the magnetized state of the magnet piece, Figure 44 is the right side 1fl1 of Figure 3, which is slightly enlarged.
1 side, 1 page].

1...Rollzoyahu l-1Ia...iA, 2.
...Magnet piece, 2a...Protrusion, iρ, 2b...Cross section of magnet piece, 2c...1 Both sides of stone piece, 3...
...Sleeve, 4...Ball hair ring, 5...
・Flange.

Claims (1)

[Scope of Claims] (1) A magnet roll for maintaining a magnetic press for a dry type electronic copying machine, which comprises a plurality of rod-shaped magnet pieces connected and fixed in the longitudinal direction of the outer surface of the shaft, wherein the plurality of 4! All of the round-shaped magnet pieces are made of plastic magnets, and each magnet piece is magnetized so that a magnetic path is formed from the outer surface to both side surfaces within its cross section. Magnet roll for magnetic bluff development. (21/In a magnet roll for developing a magnetic brush of a dry type electronic copying machine, which is made by connecting and fixing a plurality of rod-shaped magnet pieces in the longitudinal direction of the outer surface of the toft, In addition to being composed of magnets,
Each 1% stone piece is magnetized so that a magnetic path is formed from the outer surface to both side surfaces within its cross section, and the outer surface of the shaft and the surface of each of the magnet pieces that come into contact with the outer surface of the shaft. A magnet roll for magnetic plan development, characterized in that a positioning means is provided on the roll. (3) The magnetic roll for magnetic bluff development according to claim (1) or (2), wherein the cross section of the bar-shaped magnet piece is fan-shaped.