JPS648211B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a sealing device for a bearing provided in an electronic copying machine or the like.

Conventionally, various types of bearings are installed in developing devices such as electronic copying machines to support shafts such as magnetic brushes and developer transport rolls. , oil seals and felt seals are installed.
However, with these seals, in order to improve the sealing effect, it is necessary to strictly control the shaft diameter dimension tolerance, the shaft end shape, or the runout tolerance of the part that contacts the seal, and since the seal part cannot be lubricated, the seal Its durability is also low. Especially for felt seals, etc., it takes several tens of microns like a magnetic brush developer.
There were drawbacks such as insufficient sealing effect when using a thin developer of ~100μ.

This invention was made with the aim of eliminating such drawbacks, and includes a bearing for supporting a rotating body such as a roller, which is provided on the side of a container containing magnetic powder, and a bearing that supports a rotating body such as a roller inside the container. A first magnetic means is fixed to surround the rotating shaft so as to face an inner wall surface of the container, and a gap is formed between the first magnetic means and the inner wall side of the container supporting the bearing. To provide a sealing device for a bearing in which annular second magnetic means are fixedly opposed and whose opposing surfaces have the same polarity, thereby reliably preventing developer etc. from entering the bearing part. It is something.

Hereinafter, an example in which the present invention is implemented in an electronic copying machine will be described in detail with reference to the drawings. 1 and 2 show one embodiment. In the figures, 1 is a magnetic brush developing device of an electronic copying machine (not shown), and a magnetic brush roll (not shown) and a developer conveying roll 2 are accommodated in the developing device 1. The shafts 2a of these rolls 2 are rotatable via bearings 3 installed on the side frame 1a. The bearing 3 above is the side frame 1
The permanent magnet body 5 is housed in the inner bottom of the bearing 3 recessed in the shaft bearing 1b, and a permanent magnet body 5 is provided on the inner surface of the developing device 1 of the bearing 3 via a bush 4 made of a magnetic material. There is. The permanent magnet body 5 is formed into an annular shape using a ferrite magnet or the like, and is fixed to the side frame 1a by means of adhesive or the like via the bushing 4 so as to loosely surround the shaft 2a, and is attached to the shaft receiving portion. Another permanent magnet body 6 is installed at the inner opening of the developing device 1b so as to face the permanent magnet body 5 and to surround the shaft 2a. These permanent magnet bodies 5 and 6 are arranged so that the same polarity faces each other, and one permanent magnet body 5 is attached to the shaft 2a.
A magnetic field 7 is formed between the other permanent magnet body 6 and the inner surface of the bearing mounting portion 1b, and a repulsive magnetic field 8 is formed between each of the permanent magnet bodies 5 and 6. ing.

In the device configured in this way, the magnetic powder is attracted to the magnetic field 7 formed by the permanent magnet body 6, forms a wall of magnetic powder between the side frame 1a, and the magnetic powder inside the container is attracted to the bearing 3. It can prevent intrusion into the side. In addition, the magnetic field 7 formed by this permanent magnet body 6 has a much stronger magnetic powder attraction force than the repulsive magnetic field 8, so magnetic powder rarely falls into the repulsive magnetic field 8, and even if it falls, the next permanent magnet body 5 is formed. Since the magnetic powder is attracted and adhered by the magnetic field 7 with a strong attraction force, the magnetic powder does not enter the bearing 3.

In addition, the same parts in FIG. 1 and FIG. 2 are indicated by the same reference numerals, and in the above embodiment, the pair of permanent magnets 5 and 6 were installed spaced apart in the axial direction, but as shown in FIG. A pair of magnet bodies 5 and 6 may be provided twice in the vicinity of the opening of the portion 1b and spaced apart in the radial direction. In this case as well, the magnet bodies 5 and 6 are provided so that the same polarity faces each other, as shown in FIG. Although the bushing 4 is made of a magnetic material to prevent the bearing 3 from being magnetized, if the magnets 5 and 6 are placed apart from the bearing 3, the bushing 4 can be made of a non-magnetic material. You may. In this embodiment, the magnetic powder adhering to the magnetic field 7 formed by the magnets 5, 6
Form a wall between 6. Furthermore, although a repelling magnetic field 8 is formed on the opposing surfaces 12 of the magnet bodies 5 and 6, the magnetic attraction force is very weak, so that the intrusion of magnetic powder can still be effectively prevented.

Further, in the above embodiment, an example was explained in which the device was installed in the bearing of an electronic copying machine, but it may of course be installed in the bearing of various machines to prevent magnetic powder from entering the bearing. , which can be widely applied as a general sealing device.

As described in detail above, this invention provides a bearing for supporting a rotating body such as a roller on the side of a container containing magnetic powder provided in a copying machine, etc., and a bearing is provided inside the container of this bearing. A first magnetic means is fixed to surround the rotating shaft so as to face an inner wall surface of a supporting container, and a gap is formed between the first magnetic means and the inner wall of a side of the container supporting the bearing. Since the annular second magnetic means is fixedly disposed so as to face each other and have the same polarity, the (strong) magnetic field 7 formed by the first magnetic means or the second magnetic means The magnetic powder is attracted and deposited to form a wall, and the magnetic powder itself acts as a seal. In addition, since the opposing surfaces of the first magnetic means and the second magnetic means are composed of magnetic poles of the same polarity, a repulsive magnetic field 8 with a very weak magnetic attraction force is formed, so that the magnetic powder has a magnetic attraction force. Due to this relationship, it is extremely difficult for the magnetic field to penetrate in the direction of the repulsive magnetic field 8. Therefore, there is no magnetic powder reaching the bearing 3, and since the magnetic powder can be sealed without contact, it is possible to maintain sufficient sealing performance over a long period of time regardless of the rotation speed of the shaft 2a. . Furthermore, the repulsion of the permanent magnets 5 and 6 also has the effect of absorbing the play in the axial direction of the shaft 2a.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a sectional view of a bearing portion, FIG. 2 is an enlarged view of the same, and FIGS. 3 and 4 are explanatory views of other embodiments. 1 is a magnetic brush developing device, 2 is a developer transport roll, 2a is a shaft, 3 is a bearing, and 5 and 6 are permanent magnets.

Claims (1)

[Claims] 1 A bearing for supporting a rotating body such as a roller is provided on the side of a container containing magnetic powder, and a first magnetic means is provided inside the container of this bearing so as to face the inner wall surface of the container that supports the bearing. A magnet is fixedly installed so as to surround the rotating shaft, and on the side inner wall side of the container that supports the bearing, faces the first magnetic means with a gap therebetween, and has opposing surfaces having the same polarity. A sealing device for a bearing, in which a second annular magnetic means is fixedly installed.