JP2002147435A - Conductive roller and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive roller and a method of manufacturing the same capable of providing an excellent adhesiveness between a conductive elastic layer containing a polar rubber and a conductive shaft body and uniform electric characteristics, and capable of performing a uniform charge by a charge roller and a uniform transfer by a transfer roller in an electrophotographic device. SOLUTION: In this conductive roller having the conductive elastic body layer stuck, through an adhesive agent layer, to the shaft body along the outer periphery of the conductive shaft body, the conductive elastic body layer contains a polar rubber, and the adhesive agent layer is formed of a resin having ester radical in principal chain.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive roller used for a charging roller and a transfer roller in an electrophotographic apparatus, and a method for manufacturing the conductive roller.

[0002]

2. Description of the Related Art In a conventional electrophotographic apparatus, a charging device for uniformly charging the surface of an electrophotographic photosensitive member, and a transferable toner image formed on the surface of an electrophotographic photosensitive member are transferred to a sheet mainly of paper. As a transfer device for electrostatically transferring to a transfer material, a corotron charger using a corona discharge generated by applying a high voltage to a thin wire such as tungsten has been generally used. However, the method utilizing corona discharge has drawbacks such as requiring a high-voltage power supply, and adverse effects such as deterioration of the electrophotographic photoreceptor due to the strong oxidizing effect of the generated ozone. For this reason, a number of ozone-less charging and ozone-less transfer methods have been proposed in the past, but these are mainly solved by a method in which electric charge is supplied directly from a conductive charging roller or a transfer roller to an electrophotographic photosensitive member as a member to be charged. It has been.

However, with the development of color, higher definition, and higher speed, the charging roller and the transfer roller are required to have uniform charging and uniform transfer, and a roller that does not greatly change the charging potential and the transfer potential is required. Regarding the uniformity of the charging or the transfer, in order to satisfy the above performance, the configuration of the roller is such that a metal shaft is used for the conductive shaft, and a main material such as epichlorohydrin rubber, NBR and urethane rubber is used for the conductive elastic layer. Those containing polar rubber in the chain have been used to replace conventional electronically conductive rubber.

Further, since uniform charging and uniform transfer are required, it is necessary to reduce the resistance unevenness of the roller, and the conductive elastic layer is required to have high roller dimensional accuracy. Conventionally, a runout of about 0.2 mm has been required to improve the accuracy to a runout level of 0.01 mm. Further, in order to improve the surface properties and the electrical characteristics, a configuration having at least one surface layer is often adopted.

[0005] When manufacturing a roller having a conductive elastic layer using epichlorohydrin rubber, NBR or urethane rubber, two methods may be employed.

One is to set the conductive shaft in a mold,
Filling it with unvulcanized rubber and vulcanizing it to obtain the desired roller by mold vulcanization, and the other method is to form the unvulcanized rubber into a tube with an extruder and use it in a steam can or hot air oven. In this method, the desired roller is obtained by a tube press-fitting method by press-fitting the obtained conductive elastic body into a conductive shaft.

Further, in order to obtain the accuracy of the outer diameter shape, there is known a method of obtaining a desired accuracy by grinding the conductive elastic layer with a cylindrical grinder.

When a roll is manufactured by the above manufacturing method,
When the roll is rotated with the product, there is a problem that the gap occurs between the conductive shaft and the conductive elastic layer, the gap occurs due to the stress at the time of grinding, chatter occurs, and the outer diameter accuracy deteriorates. . As a solution to this problem, an adhesive is used between the conductive shaft and the conductive elastic layer.

When bonding the conductive shaft to the conductive elastic layer of epichlorohydrin, NBR, or urethane rubber, a vulcanized adhesive is generally used when molding by mold vulcanization. Can be When the vulcanized adhesive and unvulcanized rubber are molded and heated in a mold, a cross-linking reaction occurs between the rubber and the adhesive, and a strong bond occurs. Adhesive force is generated by mechanical adsorption. Such vulcanized adhesives have been provided by manufacturers for many years. Examples of the type of vulcanized adhesive include phenol-based, chloroprene-based, polyolefin-based, and epoxy-based vulcanized adhesives.

However, in the case of manufacturing by a tube press-fitting method, vulcanization bonding cannot be performed since the tube is formed into a tube by an extruder in advance and vulcanized. Post-vulcanization bonding is also possible with the above vulcanization adhesive, but in the case of post-vulcanization bonding, pressure is required on the bonding surfaces. However, with the tightening force at the time of press-fitting, the effect of post-vulcanization bonding cannot be sufficiently exhibited, and the adhesive force is weak, and the roller obtained by the above-mentioned tube press-fitting method is displaced by strong stress at the time of grinding, and the outer diameter accuracy is reduced. Worse, uniform charging and uniform transfer cannot be obtained,
This leads to the cause of image unevenness. Conventionally, the adhesive used in the tube press-fitting method has only an effect of preventing slippage between the conductive shaft and the conductive elastic layer.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic apparatus which has excellent adhesion between a conductive elastic layer containing a polar rubber and a conductive shaft and uniform electric characteristics. An object of the present invention is to provide a conductive roller capable of performing uniform charging by a charging roller and uniform transfer by a transfer roller, and a method of manufacturing the conductive roller.

[0012]

According to the present invention, there is provided a conductive roller provided with a conductive elastic layer adhered to the shaft via an adhesive layer along the outer periphery of the conductive shaft. A conductive roller is provided, wherein the conductive elastic layer contains a polar rubber, and the adhesive layer is made of a resin having an ester group in a main chain.

Further, according to the present invention, in a method of manufacturing a conductive roller provided with a conductive elastic layer adhered to the conductive shaft via an adhesive layer along the outer periphery of the conductive shaft, Extruding the elastic layer into a tube shape, vulcanizing the conductive elastic layer, disposing the adhesive layer described above along the outer periphery of the conductive shaft, A method for manufacturing a conductive roller is provided, which comprises a step of press-fitting a shaft through an adhesive layer.

[0014]

Embodiments of the present invention will be described below in detail.

That is, in the conductive roller member according to the present invention,
The reason why the conductive elastic material layer containing the polar rubber is used is that the conventionally used electron conductive rubber in which carbon black or the like is dispersed tends to have unstable resistance due to poor dispersion of carbon black. On the other hand, those containing a polar rubber have excellent resistance stability because the rubber itself shows conductivity. Alternatively, when the polar rubber is contained, even if carbon black is used, only a small amount is required, and it is hardly affected by electron conductivity. In particular, at least the epichlorohydrin rubber is contained, by adding epichlorohydrin, which is known as a low-resistance rubber among various rubbers, it is particularly necessary to add a conductive material such as carbon black for resistance adjustment. This is because a rubber having less resistance and less resistance can be obtained.

Since the adhesive used for the conductive elastic body is an adhesive having an ester group in the main chain, since it is a polar substance, it provides good adhesive strength. In the case of the tube press-fitting method, it is most suitable for bonding the rubber after vulcanization. In particular, the polyester-based adhesive is applied to the conductive shaft body by applying an adhesive and then press-fitting the tube into a tube and heating the same to a temperature equal to or higher than the melting point of the adhesive. This is for drawing. In general, a metal shaft is used for the conductive shaft body, and the adhesive between the adhesive and the metal is excellent in the same manner as the adhesive such as the epoxy-based or phenolic resin-based adhesive. It is well known that a good adhesive strength can be obtained.

The thickness of the adhesive is not particularly limited, but is preferably in the range of 3 to 30 μm from the viewpoint of workability. If the adhesive is thinner than 3 μm, places where application is impossible are likely to occur. Conversely, if the adhesive is too thicker than 30 μm, the amount of the adhesive used increases, which tends to lead to an increase in cost.

The reason that the adhesive has a lower volume resistance than that of the conductive elastic layer is that the use of the adhesive causes unevenness of the adhesive between the conductive shaft and the conductive elastic layer. This has the effect of eliminating the influence even if it is present, so as to eliminate the uneven resistance of the roller and to obtain a stable resistance.

The step of disposing an adhesive on the outer periphery of the conductive shaft includes spraying, roll coating,
In the case of a solid such as hot melt, treatment is performed by melt coating, powder coating while heating the conductive shaft, or the like. Performing with the tube press-fitting method is cheaper equipment investment than manufacturing with mold vulcanization,
This is because the production method is advantageous for mass production.

The roller and the method of manufacturing the same according to the present invention can prevent the gap between the conductive shaft and the conductive elastic layer when the conductive elastic layer is ground or when the product is used, and can prevent the outer diameter accuracy from deteriorating. There is. Therefore, the resistance becomes uniform, so that the charging roller in the electrophotographic apparatus can perform uniform charging and the transfer roller can perform uniform transfer.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

First, an SUM22 material having a diameter of 6 mm and a KN plating of 3 to 6 μm is used as a shaft, and then washed with toluene. Then, Examples 1 to 1 shown in the following Table 1
9 and those in which the type of rubber and the type of adhesive were changed under the conditions of Comparative Examples 1 to 3 were produced. An adhesive is applied to the shaft with a thickness of 10 to 20 μm using a roll coater.

The evaluation items were judged on the basis of adhesiveness, chatter state at the time of outer diameter grinding, electric resistance unevenness and image unevenness.

Regarding the adhesiveness, the product was cut with a cutter and the state of adhesion was observed. ◎: Completely adhered ○: Slight peeling ×: Not adhered

The occurrence of chattering during outer diameter grinding was visually determined on the surface. ◎… No occurrence ○… Slightly chattering ×… Normally chattering

Regarding the electric resistance unevenness, S of φ40 mm
The roller is pressed against the US drum with a load of 1 kg and 45 rpm.
The resistance was measured when 100 V DC was applied from the cored bar for 2 seconds, and the maximum value was divided by the minimum value.

With respect to the evaluation of image unevenness, evaluation was performed by incorporating a charging roller manufactured and producing halftone. ◎: uniform image ○: slightly uneven ×: clearly uneven

[0028]

[Table 1]

<Material of Elastic Layer> Epichlorohydrin Rubber: Epichroma manufactured by Daiso Corporation
-1.0 × 10 based on CG105^Five~ 3.0 × 10^Five
Resistance adjustment to Ω · cm NBR: Nipole 1042 manufactured by Zeon Corporation
1.0 × 10^Five~ 3.0 × 10^FiveResistance to Ω · cm
Epichlorohydrin rubber + EPDM: Nippon Synthetic Rubber
EP37C manufactured by the above-mentioned epichlorohydrin rubber rubber
And 1: 1 by mass ratio and 1.0 × 10^Five~ 3.0
× 10^FiveResistance adjustment to Ω · cm Urethane rubber: Urethane 0359G manufactured by Bayer K.K.
1.0 × 10 on base ^Five~ 3.0 × 10^FiveResistance to Ω · cm
Adjustment

<Material for Adhesive> Polyester: PES310S manufactured by Toa Gosei Chemical Co., Ltd.
Adjusting conductivity by adding carbon black based on 30 Ester urethane: P26 manufactured by Nippon Milactran Co., Ltd.
S is dissolved in DMF based on DMF and carbon black is added to adjust conductivity. Phenol ... Metaloc UB manufactured by Toyo Chemical Laboratory Co., Ltd.
To adjust the conductivity by adding carbon black based on olefins. CH made by Lord Far East Co., Ltd.
Adjust conductivity by adding carbon black based on EMLOK252X

Two molding methods were used for the test. One was a mold vulcanization method in which an adhesive was applied to a shaft, rubber was filled in a mold and vulcanized. The other is to knead the conductive unvulcanized rubber and extrude it into a tubular shape using a uniaxial extruder. Thereafter, vulcanization was performed at 150 ° C. for 30 minutes in a vulcanization can. The resulting vulcanized tube is pressed into a shaft coated with an adhesive on the outer periphery, and the adhesive is heated to a melting point or higher.
Heating was performed at 150 ° C. for 20 minutes to perform bonding. The outer diameter of the roller obtained by each method was ground and coated with a urethane paint by dipping to form a surface layer. The conductive elastic layer has a volume resistance of 1.0 × 10 ^{5 to} 3.0 × 10 ⁵ Ω.
・ The one adjusted to cm was used.

In Examples 1 to 9, the adhesiveness was generally good, uniform resistance was obtained, and good charging performance was obtained. In Examples 1 and 3 containing at least epichlorohydrin rubber, the best results were obtained when molded by a tube method and a polyester-based adhesive was used. In Example 5, since the volume resistance of the adhesive was higher than that of the conductive elastic body, the resistance unevenness was large, and there was no adhesion or chattering. However, the resistance unevenness occurred, and the image evaluation was slightly inferior to Example 1. In Comparative Examples 1 and 2, the adhesive peeled off, chatter occurred during grinding, and image defects occurred.

[0033]

According to the results of the above Examples and Comparative Examples,
The use of an adhesive with an ester group, which is a condensation skeleton, along the outer periphery of the conductive shaft body, with the conductive elastic body being a polar rubber, provides excellent adhesion, has no chatter during grinding, and has no image unevenness. Thus, it has become possible to provide a conductive roller and a method for manufacturing the same, which can obtain uniform electric characteristics and can perform uniform charging with a charging roller and uniform transfer with a transfer roller in an electrophotographic apparatus.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) G03G 15/16 103 G03G 15/16 103 (72) Inventor Hideo Kondo 1888-2 Kusazaki, Kisazaki-cho, Inashiki-gun, Ibaraki Pref. Incorporated (72) Inventor Hiroshi Inoue 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 2H003 BB11 CC05 2H032 AA05 3J103 AA02 AA13 AA32 AA69 BA41 EA02 EA07 FA10 FA14 FA18 GA02 GA52 GA57 GA58 GA60 GA74 HA03 HA05 HA12 HA20 HA31 HA45 HA53

Claims (5)

[Claims] 1. A conductive roller provided with a conductive elastic layer adhered to the shaft via an adhesive layer along the outer periphery of the conductive shaft, wherein the conductive elastic layer is polar. A conductive roller comprising a rubber, wherein the adhesive layer is made of a resin having an ester group in a main chain. 2. The conductive roller according to claim 1, wherein said conductive elastic layer is extruded into a tube shape and vulcanized, and is press-fitted along the outer periphery of said conductive shaft to form a roller. . 3. The conductive roller according to claim 1, wherein the conductive elastic layer contains at least epichlorohydrin rubber, and the adhesive is a polyester-based adhesive. 4. The conductive roller according to claim 1, wherein a volume resistance of the adhesive is lower than a volume resistance of the conductive elastic layer. 5. A method for manufacturing a conductive roller having a conductive elastic body layer adhered to the shaft body via an adhesive layer along the outer periphery of the conductive shaft body, the method comprising: A step of extruding into a tube shape, a step of vulcanizing the conductive elastic layer, and disposing the adhesive layer according to any one of claims 1, 3 and 4 along an outer periphery of the conductive shaft. And a step of press-fitting the conductive shaft with an adhesive layer through an adhesive layer.