JPS609799Y2 - Magnet roll for electrostatic recording - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrostatic recording magnet roll used in electrophotographic copying machines, facsimile machines, printers, etc.

In the conventionally commonly used magnetic brush development method, when developing photosensitive paper or a photosensitive drum that has an electrostatic latent image that has undergone the process of charging and exposure, a magnetic roll having multiple magnetic poles on its surface is rotated. The electrostatic latent image is developed by rubbing the electrostatic latent image with a developer attached in the form of a brush on the surface of the magnet roll.

As this magnet roll, one in which a cylindrical permanent magnet is usually fixed to a shaft, or one in which a plurality of block magnets are connected and fixed to a shaft is used.

In recent years, it has been desired to reduce the weight and cost of these permanent magnet rolls.

An object of the present invention is to provide a lightweight and inexpensive magnet roll for electrostatic recording.

The electrostatic recording magnet roll of the present invention has a pair of approximately disk-shaped magnet holding members that have a plurality of steps along the circumference and have a circular arc-shaped notch in a part of the outer circumferential surface. facing each other at intervals, fitting an end portion of a block-shaped permanent magnet into each of the step portions, and protruding a shaft from each of the magnet holding members;
A sheet made of a non-magnetic material is applied to the outer peripheral surface to form a permanent magnet member, and the permanent magnet members are arranged in a non-magnetic cylinder so as to be able to rotate relative to each other.

The details of the magnet roll of the present invention will be explained with reference to the drawings showing one embodiment.

FIG. 1 is a partially sectional front view of the magnet roll of the present invention, and FIG. 2 is a sectional view taken along line A-A.

In these figures, 1a, 1b 76 and IC are permanent magnets such as ferrite magnets, rubber magnets, rare earth magnets, etc., and are magnetized with N and S poles extending in the axial direction.

Reference numerals 2 and 2' designate metal magnet holding members, a portion of which is bent to form stepped portions 2a and 2'a, respectively, to which the ends of the permanent magnets are fixed.

Note that 2b and 2'b are shafts that are press-fitted into the magnet holding members 2 and 2', respectively.

Further, 2C and 2'c are flat parts formed by cutting out a part of the magnet holding members 2 and 2', respectively, in a circular arc shape.
This serves as a reference surface when assembling the magnet roll.

In other words, the presence of this flat portion allows assembly to be performed extremely easily and with high precision.

Therefore, it can be easily assembled by arranging the magnet holding members 2 and 2' to face each other at a predetermined interval, and then placing the ends of the permanent magnets 1a, lb, and 1c on the steps and fixing them with adhesive or the like.

After assembly, a sheet made of a non-magnetic material such as a polyester film 3 may be tightly attached to the outer circumference of the magnet (specifically, the entire magnet may be covered with a polyester tube such as that used in a well-known insulating sleeve and heated. This can further increase the strength of the magnet roll.

Next, numeral 4 is a cylinder made of a non-magnetic material such as aluminum or stainless steel, which is placed outside the permanent magnet at a slight interval, and side plates 5 and 5' are fixed to the ends.
It is rotatably mounted on the shafts 2b and 2'b by bearings 6 and 6'.

In addition, although the magnet holding member was made of metal in the above,
However, it may be made of synthetic resin.

Further, instead of bending a part of the magnet holding member, a groove may be formed in the magnet holding member and this groove may be used as a stepped portion.

As described above, the electrostatic recording magnet roll of the present invention has a hollow interior compared to conventional magnet rolls, and therefore can be lighter in weight.

Furthermore, since a simple holding member is used instead of the shaft for fixing the magnet, it can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional front view of the magnet roll of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. 1a = tb, lc: magnet, 2.2': magnet holding member, 2a, 2'a: step, 2b, 2'b: shaft, 2c, 2'
c: flat area.

Claims (1)

[Claims for Utility Model Registration] ■ A permanent magnet member having a plurality of block-shaped permanent magnets fixed to the outer peripheral surface is arranged inside a non-magnetic cylinder, and the permanent magnet member is rotatable relative to the non-magnetic cylinder. In the supported electrostatic recording magnet roll, a pair of substantially disk-shaped magnet holding members having a plurality of steps along the circumferential direction and having a part of the outer circumferential surface cut out in the shape of an arc are placed at a predetermined interval. an end portion of the block-shaped permanent magnet is fitted into each of the step portions, a shaft is provided protruding from each of the magnet holding members, and a sheet made of a non-magnetic material is provided on the outer peripheral surface. 1. A magnet roll for electrostatic recording, characterized in that the permanent magnet member is formed by adhering the permanent magnet member. 2. The magnet roll for electrostatic recording according to claim 1, wherein the magnet holding member is formed of a metal plate, and a stepped portion is formed by bending a part of the metal plate. 3. The magnet roll for electrostatic recording according to claim 1, wherein the magnet holding member is provided with grooves to form stepped portions.