JP3211486B2 - Developing cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a copying machine, a facsimile,
Further, the present invention relates to a developing cylinder used in a dry electrophotographic developing device such as a laser beam printer, and more particularly to a developing cylinder capable of preventing vibration and noise due to rotation of a magnet roll.

[0002]

2. Description of the Related Art As shown in FIG. 4, for example, in a developing device of a copying machine or a facsimile, a non-magnetic material is usually provided outside a magnet roll M having a substantially cylindrical magnet fixed to a shaft A. Cylindrical sleeve SL
The magnet roll M is rotatably supported by sealing both ends with flanges 3 and 4 and receiving one end 1 of the shaft of the magnet roll M with a bearing 5 such as a bearing. The portion 2 is supported by a bearing 5 and the sleeve 4
L and project the magnet roll M into the sleeve S
L is installed in a non-contact state. While the flange 3 is fixedly supported, a rotational driving force is applied to the one end 2 of the shaft to rotate the magnet roll M with respect to the sleeve SL, thereby magnetically adsorbing a toner made of a magnetic material to the surface of the sleeve SL, The image is transferred onto an electrostatic latent image formed on a photosensitive drum.

[0003] The flanges 3, 4 support the load of the magnet roll M and serve as bearings for the rotation of the magnet roll M, so that high mechanical strength and accuracy are required, and at the same time, a voltage is applied to the sleeve SL. In this case, a material having conductivity is required. In response to such a request, conventionally, a so-called engineering plastic such as polyacetal or ABS resin filled with a conductive dispersant such as carbon black or metal powder has been used.

The sleeve SL is made of a non-magnetic and conductive metal material such as stainless steel or aluminum.

[0005]

In the developing cylinder according to the prior art as described above, the bearing 5 embedded in the flange 3, the shaft A of the magnet roll M, the flange 4 due to the dimensional tolerance existing between the components. In some cases, the coaxiality of the bearing 5 embedded in the sleeve may not be completely obtained, and when the magnet roll M is rotated with respect to the sleeve SL, there is a problem that the entire developing cylinder vibrates. For the flanges 3 and 4, a material in which conductive powder is dispersed in an engineering plastic such as polyacetal or the like is used. Since the sleeve SL is usually a metal, vibration caused by rotation of the magnet roll M is absorbed. However, this leads to amplification of vibration and noise. Further, since the fitting portions between the flanges 3 and 4 and the sleeve SL are fixed with a conductive adhesive, or the flanges 3 and 4 are simply pressed into the inner diameter portion of the sleeve SL, loosening or displacement due to vibrations may occur. To be reminded.

That is, in the prior art, vibrations and noises are generated due to dimensional tolerances, which are generally unavoidable for assembled parts, and the performance of the developing cylinder is deteriorated due to loosening or displacement of the fitting portion. Had disadvantages.

[0007]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above problems, and provides a developing cylinder free from vibration and noise. In a sleeve closed by a flange, rotatably housed a magnet roll formed with a plurality of magnetic poles on the outer peripheral surface, in a developing cylinder used in a dry electrophotographic apparatus, at least one of the flange or the sleeve, Hot-melt liquid crystal that is a vibration absorbing resin
It is in the place of using the polymer, in the developing cylinder to the second, and at least one said sleeve of said flange, hot-melt-type liquid crystal polymer is a vibration-absorbing resin
Ru near the place to be integrally molded in the over.

[0008]

According to the developing cylinder of the present invention, the flange and the sleeve formed of the heat-melting liquid crystal polymer which is a vibration absorbing resin absorb the vibration generated by the magnet roll, so that the entire developing cylinder vibrates. Can be suppressed. In addition, the integral molding of the at least one flange and the sleeve with the heat-melting liquid crystal polymer , which is a vibration absorbing resin , reduces the number of parts constituting the developing cylinder, reduces the number of fitting portions, and further reduces the vibration. This is to increase the absorption efficiency.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a heat-melting liquid crystal polymer is used as a material for a flange, a sleeve or an integrally formed body of a flange and a sleeve. As the liquid crystal polymer, a so-called polyester, polyesteramide, polyazomethine or the like is used. Main-chain liquid crystal polymers are suitable. Molding is performed by injection molding, molding is performed in the liquid crystal state by setting the molding temperature lower than the temperature at which it completely melts and becomes an isotropic fluid, and the dimensional accuracy is conventionally used by reducing the molding shrinkage. It can be higher than polyacetal or ABS resin used. Also, when applying a voltage to the sleeve, it is necessary to impart conductivity, but in this case, as in the conventional case,
Carbon black or metal powder may be filled in a range of up to about 60% by volume. Silver powder or copper powder is suitable as the metal powder. Further, when the bearing of the shaft A of the magnet roll M is a sliding bearing, graphite or molybdenum disulfide may be appropriately dispersed in order to reduce the friction coefficient during sliding.

[Example 1] As a flange material, a particle diameter of 3 was used.
A pellet of Hoechst Celanese Vectra, which is a main-chain polyester-based hot-melt liquid crystal polymer containing 30% by volume of an atomizer copper powder of 30 μm or less, was prepared.
Injection molding was performed at a cylinder temperature of 0 ° C. to obtain flanges 3 and 4 shown in FIG. The sleeve SL has an outer diameter of 18 mm,
An aluminum tube having a length of 240 mm is used, a magnet roll M having a stainless steel shaft A having an outer diameter of 3 mm pierced through a bonded magnet is mounted via bearings 5 and 5, and a conductive epoxy adhesive is used between the flange and the sleeve. And fixed. The flange 3 was fixed to the developing device cabinet, and a rotational driving force was applied to one end 2 of the shaft A of the magnet roll M to rotate the magnet roll M with respect to the sleeve SL. As a result, it was confirmed that the vibration generated by the rotation of the magnet roll M was reduced to about one third at its maximum amplitude as compared with the case where a flange made of a conventional polyacetal resin was used. Noise also decreased. In addition, good conductivity was obtained between the flange and the sleeve in terms of conductivity.

Example 2 A flange and a sleeve fixed to a developing device cabinet were made of Zyder pellets manufactured by Nippon Petrochemical Co., Ltd., which is a main chain polyester liquid crystal polymer containing 30% by volume of atomizer silver powder having a particle size of 3 μm. It was fabricated and integrally molded by injection molding at a molding temperature of 370 ° C. to obtain an integrally molded flange / sleeve 6 having an outer diameter of 18 mm, one of which was sealed. A magnet roll M having a stainless steel shaft A having an outer diameter of 3 mm penetrating through a bonded magnet is mounted via a rolling bearing 5, and an opening at one end is made of the same liquid crystal polymer material and a flange made of the same manufacturing method. At 4, the resin was sealed and fixed with an epoxy-based conductive adhesive to obtain a developing cylinder as shown in FIG. The protruding end portion 7 of the flange / sleeve integral molded body 6 is fixedly supported on the developing device cabinet, and a rotational driving force is applied to one end side 2 of the shaft A of the magnet roll M so that the flange / sleeve integral molded body 6 The magnet roll M was rotated. As a result, the vibration generated by the rotation of the magnet roll M is at its maximum amplitude,
It was confirmed that the number was reduced to about one-fifth as compared with the case where a flange made of a conventional polyacetal resin and an aluminum sleeve were used. In addition, noise and conductivity were also measured in Example 1.
Similarly, good characteristics were shown.

[Embodiment 3] Flanges 3, 4 and sleeve S
L is a main chain polyester liquid crystal polymer containing 15% by volume of atomizer silver powder having a particle size of 3 μm and 15% by volume of graphite having a particle size of 2 μm. Injection molding was performed at a temperature of 340 ° C., and continuous extrusion molding was performed at a similar temperature for the sleeve, to obtain respective molded products. A magnet roll M having a stainless steel shaft A having an outer diameter of 3 mm penetrating through a bonded magnet is mounted inside the sleeve SL while being supported by the flanges 3 and 4 without using any special bearing parts, and is developed as shown in FIG. I got a cylinder. For fixing the flanges 3 and 4 to the sleeve SL, a conductive epoxy adhesive was used. The flange 3 is fixedly supported on the developing device cabinet, and the magnet roll M
A rotational driving force was applied to one end side portion 2 of the shaft A to rotate the magnet roll M with respect to the sleeve SL. As a result, the vibration generated by the rotation of the magnet roll M at its maximum amplitude is smaller than that in the case where the flange made of the conventional polyacetal resin and the aluminum sleeve are used.
It was confirmed to decrease from about one third to one fifth. As for the noise and the conductivity, as in the first and second embodiments,
Good results were obtained.

[0013]

As described above, according to the first aspect of the invention, the sleeve or flange of the developing cylinder is provided with a vibration-absorbing resin, particularly a hot-melt type resin which is a kind of liquid crystal polymer resin.
By using liquid crystal polymer , the vibration caused by the rotation of the magnet roll can be greatly reduced, so the noise generated by the vibration and the loosening and displacement of the fitting part are eliminated, and stable mechanical operation is maintained for a long time. be able to.
In particular, liquid crystal polymer-based resins have low molding shrinkage and extremely excellent dimensional stability, and when used in a developing cylinder, lead to an improvement in processing accuracy and a reduction in the rate of dimensional defects, which in turn leads to a reduction in the cost of the developing cylinder. . According to the second aspect of the present invention, the flange and the sleeve are integrally formed of the vibration-absorbing resin, so that vibration and noise can be further reduced, and the number of parts is reduced, so that the number of assembling steps of the developing cylinder can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a structure of a developing cylinder according to an embodiment of the first invention.

FIG. 2 is an explanatory view showing a structure of a developing cylinder according to an embodiment of the second invention.

FIG. 3 is an explanatory view showing a structure of a developing cylinder according to another embodiment of the first invention.

FIG. 4 is an explanatory view showing a structure of a developing cylinder in a conventional technique.

[Explanation of symbols]

 A Shaft M Magnet roll SL Sleeve 1, 2 Shaft end 3, 4 Flange 5 Rolling bearing 6 Flange, sleeve integral molding 7 Flange tip

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-192067 (JP, A) JP-A-4-189215 (JP, A) JP-A-3-163230 (JP, A) 129161 (JP, U) Shokai Sho 57-148155 (JP, U) Shokai Hei 3-72114 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08-15 / 095 F16C 13/00

Claims (2)

(57) [Claims] 1. A developing cylinder used in a dry electrophotographic apparatus comprising a magnet roll having a plurality of magnetic poles formed on an outer peripheral surface rotatably housed in a sleeve closed by a flange. A developing cylinder characterized in that at least one of the heat-melting liquid crystal polymers that is a vibration absorbing resin is used. 2. A plurality of sleeves, each of which is enclosed in a sleeve closed by a flange.
Can rotate a magnet roll with the magnetic poles formed on the outer surface
Used in a dry electrophotographic apparatus
Shake one flange and the sleeve.
Integrally formed by a heat-melting liquid crystal polymer that is a dynamic absorbing resin
A developing cylinder characterized by being shaped.