JP2601510Y2 - Magnetic cylinder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic cylinder used for a developing device and a cleaning device of a dry electrophotographic apparatus such as a copying machine, a facsimile, and a laser beam printer.

[0002]

2. Description of the Related Art For example, as shown in FIG. 2, a developing device of a copying machine or a facsimile machine usually comprises a cylindrical member made of a non-magnetic material outside a magnet roll m having a cylindrical magnet fixed to a shaft a. A sleeve s of a shape is externally fitted, both ends are sealed with flanges b and c, and one end d of the shaft of the magnet roll m is rotatably supported by being received by a bearing e such as a bearing.
The other end f of the magnetic cylinder is supported by a bearing e, and penetrates through the flange c to protrude to the outside of the sleeve s. ing. In this magnetic cylinder, the other end f of the shaft is fixedly supported, a rotational driving force is applied to the flange b, and the magnet roll m is rotated with respect to the sleeve s. And is transferred onto an electrostatic latent image formed on the photosensitive drum. The flanges b and c support the load of the magnet roll m and have high mechanical strength and accuracy by being a bearing against the rotation of the magnet roll m. For example, so-called polyacetal or ABS resin is used. So-called engineering plastics have been used. For the sleeve s, a metal material such as stainless steel or aluminum is usually used as a nonmagnetic and conductive material.

[0003]

In the developing cylinder according to the prior art as described above, the bearings e and b embedded in the flange b due to the dimensional tolerance existing between the respective components.
In some cases, the coaxiality of the shaft e of the magnet roll m and the bearing e embedded in the flange c cannot be completely achieved, and when the magnet roll m is rotated with respect to the sleeve s, the entire developing cylinder vibrates. There was a problem. For the flanges b and c, what is called engineering plastic such as polyacetal is used. Since the sleeve s is usually made of metal, the vibration caused by the rotation of the magnet roll m is not absorbed, and This leads to amplification and noise. Further, the fitting portion between the flanges b and c and the sleeve s is fixed with an adhesive, and there is a concern that the fitting may be loosened or misaligned due to vibration. That is, the prior art has a drawback that vibration and noise are generated by the influence of dimensional tolerance where assembly of parts is generally unavoidable, and the performance of the magnetic cylinder is deteriorated by loosening or displacement of the fitting portion. It was.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a magnetic cylinder free from vibration and noise. The feature is that the sleeve is closed at both ends by flanges
Inside a rotatable magnet roll
In the cylinder, one flange and magnet roll
Are integrally formed, and this flange part is
Can be rotated with respect to the sleeve with the mating surface of
It is slidably supported . In addition, it is also considered that a solid lubricant or a liquid lubricant is dispersed in at least one of the magnet roll and the sleeve.

[0005]

In the magnetic cylinder of the present invention, one of the flanges and the magnet roll are integrally formed. On the one hand, the shaft is supported by the bearing, and on the other hand, the fitting surface with the sleeve. Rotates as a sliding surface.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the structure of a magnetic cylinder according to the present invention, in which a magnet roll 2 integrally formed with a flange 1 at one end is housed in a sleeve 3 and the other end is closed with a flange 4. The shaft 5 at the other end of the roll 2 is supported via a bearing 6. The shaft 7 on one end of the magnet roll 2
Is fixedly supported, and a rotational driving force is applied to a shaft 8 provided on the flange 4, whereby the sleeve 3 rotates with respect to the magnet roll 2. At this time, as is apparent from the drawing, the fitting portion 9 between the magnet roll 2 and the sleeve 3 serves as a rotary sliding surface. Therefore, it is desired that the magnet roll 2 has excellent lubricity with the sleeve 3, and the addition of a solid lubricant or a liquid lubricant is considered.

The magnet roll 2 is made of an isotropic or anisotropic bonded magnet made of a plastic such as polyamide and integrally molded into a roll shape by injection molding, press molding or the like, and magnetized with predetermined magnetic poles. As solid lubricants that can be added, graphite, lead, fluorinated graphite, molybdenum disulfide and the like can be used. As liquid lubricants, general machine oil and grease can be used. In particular, when a liquid lubricant is used, the magnet roll 2 is formed in two colors, and the sliding portion is impregnated with the liquid lubricant, or the magnet roll 2 is formed so that the foaming ratio does not decrease as the distance from the sliding surface increases. However, it is also possible to impregnate the sliding portion with a similar liquid lubricant. A sufficient effect can be obtained by adding such a lubricant to the magnet roll 2 side, but it is of course possible to add the lubricant to the sleeve 3 side. In this case, particularly when a synthetic resin is used as the material of the sleeve 3, it is necessary to secure conductivity to apply a voltage to the sleeve 3. Therefore, a conductive dispersant is separately added to the sleeve 3 together with the magnet roll 2 and the flange 4. In some cases, however, when graphite or lead is dispersed as a lubricant, addition of a special conductive dispersing agent is not required because graphite or lead itself has conductivity. On the other hand, when dispersing molybdenum disulfide, molybdenum disulfide is a semiconductor, and when dispersing fluorinated graphite, it is an insulator. Therefore, a separate conductive dispersant is required. In this case, it is convenient to use a dispersant that is a conductor such as graphite or lead described above and does not impair the lubricity of the sliding surface. Furthermore, using a porous metal such as sintered bronze as the sleeve 3,
This can be impregnated with a liquid lubricant.

Next, an embodiment of the present invention will be described in more detail. As a magnet roll material, pellets composed of polyamide and magnetic powder to which 30% by volume of flaky graphite having a particle size of 5 to 10 microns and a stabilizer are added are molded by an injection molding machine, and assembled with an aluminum sleeve 3, A magnetic cylinder having the sectional structure of FIG. 1 was obtained. A shaft 7 at one end of the magnet roll 2 is fixedly supported on the developing device cabinet side, and a rotational driving force is applied to a shaft 8 provided on the flange 4 to rotate the sleeve 3 with respect to the magnet roll 2. No wear was observed on either the sleeve 2 or the sleeve 3, and a stable mechanical operation equivalent to that of a conventionally used rolling bearing was confirmed. In addition, as a result of the reduction in the number of parts as compared with the related art, the coaxiality has been improved and noise has been eliminated. Furthermore, the same favorable effects as described above were confirmed when scaly molybdenum disulfide or fluorinated graphite was added instead of the scaly graphite. Further, it can be similarly used for a cleaning device.

[0009]

As described above, according to the present invention, the number of parts constituting the magnetic cylinder is reduced as compared with the prior art, so that the number of assembling steps can be reduced, so that an inexpensive magnetic cylinder can be provided. is there. In addition, since the number of parts is reduced, the displacement of each part after assembly is smaller than before, noise during rotation due to dimensional tolerance is reduced, and it is not necessary to make the accuracy of coaxiality strict. This can also contribute to reducing the cost of the magnetic cylinder.
This also improves the durability of the magnetic cylinder.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing the structure of a magnetic cylinder according to the present invention.

FIG. 2 is an explanatory sectional view showing the structure of a conventional magnetic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flange part 2 Magnet roll 3 Sleeve 4 Flange 5, 7, 8 Shaft 6 Bearing 9 Fitting part a Shaft b, c Flange e Bearing m Magnet roll s Sleeve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-332317 (JP, A) JP-A-58-118454 (JP, U) JP-A-63-9107 (JP, U) JP-A-1 62561 (JP, U) Japanese Utility Model Hei 1-135453 (JP, U) Tokuhyo Hei 3-503319 (JP, A) (58) Fields surveyed (Int. Cl. ⁶ , DB name) G03G 15/08-15 / 095 G03G 21/00 316

Claims (3)

(57) [Scope of request for utility model registration] 1. A magnetic cylinder having a magnet roll rotatably housed in a sleeve whose both ends are closed by flanges, wherein one of the flanges and the magnet roll are
Are integrally formed, and this flange part is
The mating surface is used as a sliding surface so that it can rotate relative to the sleeve.
A magnetic cylinder characterized by being dynamically supported . 2. The magnetic cylinder according to claim 1, wherein a solid lubricant is dispersed in at least one of the magnet roll and the sleeve. 3. The magnetic cylinder according to claim 1, wherein a liquid lubricant is dispersed in at least one of the magnet roll and the sleeve.