JPH0525459U - Magnettrol - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a magnet roll that is easy to process and has a high developer transporting property. [Structure] A permanent magnet member having a plurality of magnetic poles extending in the axial direction on its outer peripheral surface, and a hollow cylindrical sleeve made of a non-magnetic material are relatively rotated via flanges provided at both ends thereof. In a freely configured magnet roll, the depth of the sleeve surface that extends in the axial direction is 0.1.
Multiple grooves of ~ 1mm are provided at a predetermined interval in the circumferential direction, and the surface of the sleeve is 10 ~ 100μm.
It is formed to have a surface roughness of (R _Z ).

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnet roll used for, for example, a developing roll in electrophotography and electrostatic recording.

[0002]

[Prior Art]

 Many magnet rolls conventionally used for developing rolls in electrophotography, electrostatic recording, etc. have a structure as shown in FIG. In FIG. 3, reference numeral 1 denotes a permanent magnet member, which is integrally molded into a cylindrical shape with a sintered powder magnet material such as hard ferrite, or a cylindrical shape with a mixture of a ferromagnetic material and a binder. The shaft 2 is coaxially fixed to the shaft.

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, flanges 3 and 4 are rotatably attached to both ends of the shaft 2 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 made of a non-magnetic material such as aluminum alloy or stainless steel. A seal member 7 is fitted between the flange 3 and the shaft 2. The permanent magnet member 1 often has a diameter of 15 to 60 mm and a length of 200 to 350 mm.

With the above configuration, the magnetic developer is applied to the outer peripheral surface of the sleeve 6 by the relative rotation between the permanent magnet member 1 and the sleeve 6 (for example, the permanent magnet member 1 is fixed and the shaft 2 is rotated). Is adsorbed to form a magnetic brush, and a predetermined developing operation or the like is performed.

[0005]

[Problems to be solved by the device]

 In the magnet roll having the above-mentioned structure, a means for roughly forming the surface of the sleeve 6 is adopted in order to improve the transportability of the developer. As such a means, there is a blasting process in which fine hard particles are projected onto the surface of the sleeve 6 (see, for example, Japanese Patent Publication Nos. 15711/1 and 32506/1989). However, there is a problem that the surface roughened by the blasting process is easily worn during use and the durability is poor.

Next, there is a means for forming a rough surface on the surface of the sleeve 6 by knurling (see, for example, JP-A-54-79043). In this case, the advantage is that the wear resistance is relatively large, but on the other hand, the processing time and processing man-hours are large, and especially in the case of the thin sleeve 6, the pressing force of the knurl tool during processing There is a drawback that deformation may occur due to.

There is also a means for forming a plurality of axially extending grooves on the surface of the sleeve 6 (see, for example, Japanese Patent Publication No. 61-30271). However, even with such means, there is a problem that the developer is apt to slip because the flat portion exists between the adjacent grooves.

An object of the present invention is to solve the problems existing in the above-mentioned prior art, and to provide a magnet roll that is easy to process and has high transportability of an image developer.

[0009]

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, a permanent magnet member having a plurality of magnetic poles extending in the axial direction on the outer peripheral surface thereof, and a hollow cylindrical sleeve made of a nonmagnetic material are provided at both ends of these members. In a magnet roll configured so as to be rotatable relative to each other via a flange provided in the portion, a plurality of grooves having a depth of 0.1 to 1 mm extending in the axial direction are provided on the surface of the sleeve at predetermined intervals in the circumferential direction. The technical means of forming the surface of the sleeve to have a surface roughness of 10 to 100 μm (R _Z ) was adopted.

In the present invention, if the depth of the groove is less than 0.1 mm, the locking force of the developer on the sleeve surface is insufficient, the sleeve is likely to be formed, and the transportability of the developer is deteriorated, which is not preferable. On the other hand, if the groove depth exceeds 1 mm, the effect of improving the transportability becomes substantially saturated, and the time and man-hours required for groove processing increase, which is not preferable. Since the thickness of the sleeve is generally small, if the groove depth exceeds 1 mm, the strength of the sleeve is reduced, which is not preferable.

Next, if the surface roughness of the sleeve is less than 10 μm (R _Z ), the coefficient of friction becomes small and the transportability of the developer decreases, which is not preferable. On the other hand, even if the surface roughness exceeds 100 μm (R _Z ), the effect of further improving the transportability of the developer cannot be expected. As a means for roughly forming the surface of the sleeve in this way, a blasting process in which hard particles such as fine-grained steel balls and ceramic particles are projected is effective.

[0012]

[Action]

 With the above structure, the magnetic carrier that constitutes the developer can be locked in the groove, and it is expected to prevent slipping between the developer layer and the sleeve surface between adjacent grooves. it can.

[0013]

【Example】

FIG. 1 is an enlarged cross-sectional view of essential parts showing a sleeve according to an embodiment of the present invention. In FIG. 1, the sleeve 6 is made of, for example, SUS304 and has an outer diameter of 41 mm and an inner diameter of 37 mm. Reference numeral 8 denotes a groove, which is provided on the surface of the sleeve 6 at equal intervals in the circumferential direction (7 ° 12 ′, 50 equal parts). The cross section of the groove 8 was a V groove having an angle of 60 ° and was engraved at a depth of 0.5 mm. Next, the surface of the sleeve 6 was blasted by steel ball projection to form a surface roughness of 50 μm (R _Z ).

The sleeve 6 formed as described above is assembled in a magnet roll as shown in FIG. It has been confirmed that the developer (including toner concentration 3% by weight) has extremely good transportability and has a significantly long life when continuously copied.

FIG. 2 is a schematic view showing a state where the developer is attached to the sleeve surface, and the same portions are denoted by the same reference numerals as those in FIG. In FIG. 2, 9 is a magnetic carrier, on the surface of which fine toner particles (not shown) are electrostatically adhered. The magnetic carrier 9 is adsorbed on the surface of the sleeve 6 and conveyed by the magnetic attraction force of a permanent magnet member (not shown, see reference numeral 1 in FIG. 3) provided coaxially with the sleeve 6. As is clear from FIG. 2, the magnetic carriers 9 are connected in a chain form to form a layer of the developer as a whole, but a part of the magnetic carrier 9 is inserted into the groove 8 provided on the surface of the sleeve 6. There is. Therefore, a so-called locking force is generated, which prevents the magnetic carrier 9 from slipping on the surface of the sleeve 6.

On the other hand, since the surface of the sleeve 6 including the groove 8 is roughly formed by blasting, it is substantially flat like the conventional one, but has a large friction coefficient. It is transported while maintaining the magnetically attracted state without slipping. Therefore, not only the developer transportability can be improved, but also the abrasion phenomenon caused by the slip of the developer on the surface of the sleeve 6 does not occur. Therefore, the effects of improving the transportability and extending the life are obtained as described above.

In this embodiment, an example in which the sleeve 6 is made of stainless steel has been described, but the present invention is not limited to this, and other non-magnetic metal material such as aluminum or aluminum alloy may be used. Further, the cross-sectional shape of the groove 8 provided on the surface of the sleeve 6 is not limited to the V-shape, but may be other shapes such as a U-shape and a U-shape.

[0018]

[Effect of the device]

 Since the present invention has the structure and operation as described above, there is an effect that the transportability of the developer can be improved and the life can be increased by a relatively simple processing and treatment.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of essential parts showing a sleeve according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a state where a developer is attached to the sleeve surface.

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

[Explanation of symbols]

 6 sleeve 8 groove

Claims (1)

[Scope of utility model registration request] 1. A permanent magnet member having a plurality of magnetic poles extending in the axial direction on the outer peripheral surface thereof, and a hollow cylindrical sleeve made of a non-magnetic material, with flanges provided at both ends thereof. In a magnet roll configured to be rotatable relative to each other, the depth that extends in the axial direction on the surface of the sleeve.
A plurality of grooves of 0.1 to 1 mm are provided at predetermined intervals in the circumferential direction, and the surface of the sleeve is 10 to 100 μm (R
A magnet roll characterized by having a surface roughness of ( _Z ).