JP2008090236A - Method for manufacturing conductive rubber roller, and roller for electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a conductive rubber roller having improved uniformity in terms of cell diameter distribution, thereby capable of suppressing uneven hardness and uneven resistance, at a low cost, and to provide the roller used for an electrophotographic device, having the improved characteristics. <P>SOLUTION: The method for manufacturing the conductive rubber having a foam rubber layer on a conductive core material includes a vulcanization step of heating and vulcanizing foam robber layer forming material containing at least one of epichlorohydrin rubber and acrylonitrile-butadiene rubber, and p,p'-oxybis benzene sulfonyl hydrazide with microwave irradiation and heated air by means of a microwave vulcanizing furnace, when heating the material with the irradiation with the microwave in the heated air of 180 to 230°C in the furnace at the vulcanization step, the time required for the material to pass through the furnace is ≥0.5 and ≤2.0 minutes, and the temperature of the material at the ejection from the furnace rises up to ≥100 and ≤250°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a conductive rubber roller that can be used in an image forming apparatus such as an electrophotographic copying apparatus, a printer, or an electrostatic recording apparatus. In addition, a transferable image of a toner image formed and supported on an image carrier such as a photoconductor or an electrophotographic process is transferred to a recording medium such as paper or a transfer material to form an image. The present invention relates to a roller for an electrophotographic apparatus used in an electrophotographic apparatus.

  In many electrophotographic image forming apparatuses such as copying machines and printers, conductive rubber rollers such as a charging roller, a transfer roller, and a developing roller are used. In particular, a conductive rubber roller having a foam rubber layer is used. These rubber rollers are required to maintain a uniform nip width by contact with the photoreceptor in order to respond to higher speed and higher image quality of the apparatus, and it is desired that the foamed cells are dense and uniform. Yes. Conventional rubber roller manufacturing methods include vulcanization can vulcanization using high-pressure steam (Patent Document 1), vulcanization method using a mold (Patent Document 2), UHF (microwave vulcanization equipment) vulcanization using microwave irradiation. (Patent Document 3).

  In vulcanization can vulcanization, it is easy to obtain relatively fine cells, but foam cells tend to be non-uniform in the radial direction of the vulcanization tube, and a relatively large amount is required to bring the desired cells to the surface. Polishing is required.

  In mold vulcanization, when a foam rubber roller (a conductive rubber roller having a foam rubber layer) is produced by an in-mold (split mold) foaming method, there is a joint between two molds. When a rubber composition containing a chemical foaming agent is vulcanized and foamed using such a split mold, leakage of the rubber composition (parting line) occurs from this joint, and the foamed rubber after demolding This effect is likely to appear. As a result, for example, in the electrical resistance, hardness, cell shape, etc., abnormalities are likely to occur on the split mold joining surface. In foamed rubber rollers where these characteristics are desired to be uniform, it is desirable to avoid inhomogeneous characteristics. Furthermore, it takes time to set up, and it is necessary to perform mold cleaning, which is not suitable for making a large amount.

On the other hand, in UHF vulcanization, very efficient production is possible because vulcanization foaming is performed continuously using microwaves immediately after extrusion. Furthermore, it can be said that it is easy to obtain a vulcanized tube having a uniform resistance value, hardness, and cell diameter because the unvulcanized tube after continuous extrusion is uniformly heated using microwaves. However, in order to convey the extruded tube on a belt or roller, the unvulcanized tube after extrusion is heated and heated in a state where only a specific position in the circumferential direction is in contact with the belt or roller, unless special measures are taken. Vulcanization and foaming are performed. For this reason, uneven foaming tends to occur in the circumferential direction of the tube, and unevenness in hardness and unevenness due to the uneven foaming may increase. In Patent Document 3, by rotating the tube extruded from the extruder more than 1/2 turn during continuous vulcanization, variation in the vulcanization density in the circumferential direction of the roller is reduced, and it is physically very uniform. It is disclosed to obtain a good conductive roller.
JP 11-114978 A JP 2002-115714 A Japanese Patent Laid-Open No. 2002-221859

  However, in the method of Patent Document 3, a mechanism for rotating the tube is required separately, and it is considered that the roller cost increases due to an increase in the cost of the apparatus. Therefore, in a conductive rubber roller having a foam rubber layer, it is desired to establish a low-cost manufacturing method in which the foamed state, resistance value, and hardness of the rubber layer are uniform.

  An object of the present invention is to provide a method for producing a conductive rubber roller that can produce a conductive rubber roller having excellent uniformity in cell diameter distribution and having reduced hardness and resistance unevenness at a lower cost. .

  Another object of the present invention is to provide a roller for an electrophotographic apparatus that is excellent in uniformity of cell diameter distribution and has reduced hardness and resistance unevenness, and that is less expensive.

According to the present invention, in a method for producing a conductive rubber roller having a foam rubber layer on a conductive core material,
A foam rubber layer forming material containing at least one of epichlorohydrin rubber and acrylonitrile butadiene rubber and p, p'-oxybisbenzenesulfonyl hydrazide is heated by microwave irradiation and heated air using a microwave vulcanizing furnace. A vulcanization process to vulcanize,
In the vulcanization step, the foam rubber layer forming material is irradiated with microwaves in heated air at 180 ° C. or higher and 230 ° C. or lower in a microwave vulcanizing furnace, and the foam rubber layer forming material is It is characterized in that the time for passing through the inside of the microwave vulcanizing furnace is 0.5 minutes or more and 2.0 minutes or less, and the temperature at the time of discharge from the microwave vulcanizing furnace is 100 ° C. or more and 250 ° C. or less. A method of manufacturing a conductive rubber roller is provided.

  According to the present invention, there is provided a roller for an electrophotographic apparatus, wherein the base layer portion is a conductive rubber roller manufactured by the above method.

  According to the present invention, there is provided a method for producing a conductive rubber roller that can produce a conductive rubber roller having excellent uniformity in cell diameter distribution and having reduced hardness and resistance unevenness at a lower cost.

  According to the present invention, a more inexpensive rubber roller for an electrophotographic apparatus is provided which is excellent in uniformity of cell diameter distribution and suppresses unevenness in hardness and resistance.

  The foam rubber layer forming material for forming the foam rubber layer on the conductive core material contains at least acrylonitrile butadiene rubber, epichlorohydrin rubber, or a mixture thereof as a main rubber component. The foam rubber layer forming material further contains p, p'-oxybisbenzenesulfonylhydrazide as a foaming agent. In addition, conductive materials such as carbon black, fillers such as calcium carbonate, other auxiliaries and vulcanizing agents such as sulfur, organic peroxides, triazines, polyamines, thiurams, thiazoles, etc. , Guanidine-based, sulfenamide-based, dithiocarbamate-based, thiourea-based, or a mixture of several kinds thereof can be mixed.

  The acrylonitrile butadiene rubber is not particularly limited, but is preferably medium to high nitrile to low nitrile, and more preferably low nitrile.

  Epichlorohydrin rubber should be used by appropriately selecting from epichlorohydrin homopolymer, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer. Can do. Of these, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer is preferred because resistance adjustment is easy and sulfur vulcanization is possible.

  What is necessary is just to select and mix the said material suitably for the foam formation material. Preferably, the main component is low nitrile acrylonitrile butadiene rubber, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer, filler such as carbon black, sulfur, vulcanization accelerator, p, p'-oxybisbenzenesulfonyl hydrazide. , Mixed with other auxiliaries.

  When azodicarbonamide is used as a foaming agent, substances such as ammonia and cyanic acid are generated as decomposition products of azodicarbonamide, and these decomposition products act as ionic conductive materials in the material or polar in the material. May be changed. As a result, the roller resistance value may increase over time, and the roller resistance value may increase significantly especially in a high temperature and high humidity environment (for example, 32.5 ° C., relative humidity 80%). Examples of other foaming agents include N, N'-dinitrosopentamethylenetetramine and sodium hydrogen carbonate. N, N'-dinitrosopentamethylenetetramine may generate harmful formaldehyde upon decomposition, and itself is suspected to be mutagenic. Sodium bicarbonate is difficult to obtain uniform foaming and may deteriorate the environmental fluctuation of the roller resistance value. Therefore, it is desirable to use p, p'-oxybisbenzenesulfonyl hydrazide as a blowing agent.

  Heating in a microwave vulcanization furnace from the viewpoint of suppressing foaming unevenness, making the cell diameter distribution more uniform, suppressing unevenness in hardness and resistance when processed into a conductive rubber roller, and obtaining an excellent conductive rubber roller Air temperature shall be 180 degreeC or more. In addition, the heating air temperature is set to 230 ° C. or less from the viewpoint of suppressing the resistance unevenness from being easily increased due to the temperature unevenness of the tube at the conveyance site.

  The foam rubber layer forming material is conveyed from the input side to the discharge side of the microwave vulcanizing furnace for 0.5 minutes or more and 2.0 minutes or less, during which microwave irradiation and microwave addition are performed. The temperature is raised to 100 ° C. or more and 250 ° C. or less by the heated air in the sulfur furnace. If the microwave irradiation time is shorter than 0.5 minutes, it is necessary to increase the microwave output in order to raise the temperature of the foam rubber layer forming material to a desired temperature, and foaming unevenness is likely to occur. Problems arise. Furthermore, if the microwave irradiation time is shorter than 0.5 minutes, there arises a problem that the foam rubber layer forming material cannot be heated to a desired temperature. If this microwave irradiation time is longer than 2.0 minutes, the temperature rise rate of the foam rubber layer forming material is slow, and foaming unevenness is likely to occur, or the line speed is too slow, resulting in decreased productivity. However, the problem that roller cost will rise arises. By passing through the microwave vulcanizing furnace, the foam rubber layer forming material is heated to 100 ° C. or more and 250 ° C. or less at the microwave vulcanizing furnace outlet. If the temperature of the foam rubber layer forming material is less than 100 ° C at the microwave vulcanization furnace outlet, vulcanization and foaming reaction may become insufficient even if it is further heated by a subsequent hot air furnace, or foaming may occur. Problems such as unevenness are likely to occur. Conductive rubber roller due to deterioration of acrylonitrile butadiene rubber or epichlorohydrin rubber when the temperature of the foam rubber layer forming material exceeds 250 ° C at the microwave vulcanizing furnace outlet, because the temperature of the foam rubber layer forming material is high. There is concern about the deterioration of electrical and mechanical properties.

  Hereinafter, although the form of this invention is demonstrated in detail using drawing, this invention is not limited by this.

  FIG. 1 shows an embodiment of a conductive rubber roller that can be manufactured according to the present invention. This conductive rubber roller has a foam rubber layer 62 on the outer peripheral surface of the conductive core 61. As the conductive core material, a known conductive core material used for a conductive rubber roller can be used. For example, a cylindrical metal (core metal) can be used.

  FIG. 2 shows an example in which the conductive rubber roller manufactured by the conductive rubber roller manufacturing method of the present invention is used in an image forming apparatus. The image forming apparatus shown in the figure is an electrophotographic laser printer using a process cartridge, and the figure is a longitudinal sectional view showing a schematic configuration thereof. Further, the image forming apparatus shown in the figure is equipped with a transfer device having a transfer roller. The conductive roller manufactured by the conductive rubber roller manufacturing method of the present invention is used as this transfer roller.

  The image forming apparatus shown in FIG. 1 includes a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 as an image carrier. In the photosensitive drum 1, a photosensitive layer made of an organic photoconductor (OPC) is provided on the outer peripheral surface of a grounded cylindrical aluminum substrate. The photosensitive drum 1 is driven to rotate at a predetermined process speed (circumferential speed), for example, 50 mm / sec, in the direction of arrow R1 by a driving means (not shown).

The surface of the photosensitive drum 1 is uniformly charged by a charging roller 2 as a contact charging member. The charging roller 2 is disposed in contact with the surface of the photosensitive drum 1 and is driven to rotate in the direction of arrow R2 as the photosensitive drum 1 rotates in the direction of arrow R1. An oscillating voltage (AC voltage V _AC + DC voltage V _AC ) is applied to the charging roller 2 by a charging bias application power source (high voltage power source), whereby the surface of the photosensitive drum 1 is set to −600 V (dark portion potential Vd), for example. In this way, it is charged. The surface of the photosensitive drum 1 after charging is subjected to scanning exposure by laser light 3 output from a laser scanner and reflected by a mirror, that is, laser light modulated in accordance with a time-series electric digital image signal of target image information. receive. As a result, an electrostatic latent image corresponding to the target image information (the bright current portion Vl is −150 V, for example) is formed on the surface of the photosensitive drum 1.

  The developing device 4 contains toner 5. The electrostatic latent image is reversely developed as a toner image with negatively charged toner attached thereto by a developing bias applied to the developing sleeve of the developing device 4.

  On the other hand, the transfer material 7 such as paper fed from the paper supply unit P is guided by the transfer guide, and is transferred to the transfer portion (transfer nip portion) T between the photosensitive drum 1 and the transfer roller 6. The toner image is supplied so as to match the timing of the upper toner image. The toner image on the photosensitive drum 1 is transferred to the surface of the transfer material 7 supplied to the transfer portion T by a transfer bias applied to the transfer roller 6 by a transfer bias application power source. At this time, toner remaining on the surface of the photosensitive drum 1 without being transferred to the transfer material 7 (residual toner) is removed by a cleaning device. The cleaning device has a cleaning blade 8 for removing residual toner and a waste toner container 9 for storing the removed toner.

  The transfer material 7 that has passed through the transfer portion T is separated from the photosensitive drum 1 and introduced into the fixing device 10, where the toner image is subjected to fixing processing, and is discharged out of the image forming apparatus main body as an image formed product (print). The

  The transfer roller 6 has a foam rubber layer 62 on the outer peripheral surface of the cylindrical conductive core member 61.

  The foam rubber layer forming material vulcanized in the vulcanization step can be further heated using a hot air furnace. In this case, it is preferable that the foam rubber layer forming material is heated to 150 ° C. or more and 250 ° C. or less for 1 minute or more and 5 minutes or less by a hot air furnace. 150 degreeC or more is preferable from a viewpoint of completing the vulcanization | cure and foaming reaction in a microwave vulcanization furnace, or removing the decomposition | disassembly living thing etc. of an excess foaming agent. Further, from the viewpoint of preventing a decrease in electrical or mechanical properties of the conductive rubber roller due to deterioration of the rubber material, 250 ° C. or lower is preferable.

  The conductive rubber roller of the present invention can be suitably used as a roller for an electrophotographic apparatus, particularly as a transfer roller.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited by this.

[Example 1]
An apparatus for producing a conductive rubber roller by continuous vulcanization using microwaves having the configuration shown in FIG. 3 was used. This apparatus is an extrusion vulcanizing apparatus having a total length of 13 m and comprising an extruder 11, a microwave vulcanizing apparatus (UHF) 12, a hot air vulcanizing apparatus (HAV) 13, a take-up machine 14, and a regular cutting machine 15. .

  A microwave vulcanizer (UHF) 12 conveys a rubber tube extruded from the extruder 11 with a mesh belt coated with Teflon or a roller coated with Teflon resin, and a hot air vulcanizer (HAV) 13. Is transported by a roller coated with Teflon resin. The microwave vulcanizer (UHF) 12 and the hot air vulcanizer (HAV) 13 are connected by a roller coated with Teflon resin.

  The lengths of the devices 12, 13, and 14 are 4m, 6m, and 1m in order. The distance between the microwave vulcanizer (UHF) 12 and the hot air vulcanizer (HAV) 13 and between the hot air vulcanizer (HAV) 13 and the take-up machine 14 are set to be 0.1 to 1.0 m. ing.

The materials used for the foam rubber layer forming material are as follows.
Acrylonitrile butadiene rubber [Brand name: Nipol DN401LL. Nippon Zeon Co., Ltd.].
Epichlorohydrin rubber [Brand name: Zeklon 3106. Nippon Zeon Co., Ltd.].
p, p′-oxybisbenzenesulfonyl hydrazide [trade name: Neoselbon N # 1000S. Eiwa Kasei Kogyo Co., Ltd.].

  80 parts by mass of acrylonitrile butadiene rubber, 20 parts by mass of epichlorohydrin rubber, and 6 parts by mass of p, p'-oxybisbenzenesulfonyl hydrazide were kneaded using a Banbury mixer. For kneading, a closed kneader such as a kneader can be used in addition to the Banbury mixer.

  After kneading, it was formed into a ribbon shape using an open roll and a ribbon forming and dispensing machine.

  The foam rubber layer forming material formed into the ribbon shape was put into the extruder 11 of the electric rubber roller manufacturing apparatus by continuous vulcanization using the microwave and extruded into a tube shape.

  Immediately after being extruded from the extruder 11, the rubber tube molded and extruded into a tube shape from the extruder 11 has a furnace temperature (heated air temperature in the microwave vulcanization furnace) of 180 ° C. or higher and 230 ° C. or lower. It is conveyed into the furnace of the microwave vulcanizer (UHF) 12.

  In the present invention, a microwave vulcanizing furnace is used in which the heated air temperature in the furnace is set to 180 ° C. or higher and 230 ° C. or lower. In this furnace, the foam rubber layer forming material is irradiated with microwaves, and the time for the foam rubber layer forming material to pass through the inside of the microwave vulcanizing furnace is 0.5 minutes or more and 2.0 minutes or less. The temperature at the time of discharging the microwave vulcanizer is heated to 100 ° C. or more and 250 ° C. or less. As a result, the foam rubber layer forming material is vulcanized and foamed. In this example, as shown in Example 1 of Table 1, the air temperature in the microwave vulcanizing furnace was set to 180 ° C., and the rubber tube was placed in the microwave vulcanizing furnace for 0.5 minutes in the inside. The rubber tube was heated to 100 ° C. by irradiating with microwaves while transporting. The intensity of the microwave was 1.0 kW.

  Subsequently, this rubber tube was conveyed to a hot air furnace of a hot air vulcanizer (HAV) 13, where vulcanization was completed, and a tube-shaped conductive rubber molded product was produced. What is necessary is just to perform the process by a hot stove as needed, for example, 150-250 degreeC heating can be performed in 1 to 5 minutes. In this example, the heating in the hot stove was 200 ° C. for 2.3 minutes.

  Thereafter, immediately after the rubber tube is discharged from the winder 14, the rubber tube is cut into a desired size by a standard cutting machine 15 to produce a tube-shaped conductive rubber molding (foam rubber molding). did.

  A conductive core material having a diameter of 4 to 10 mm coated with a hot melt adhesive in a desired region is press-fitted into the inner diameter portion of the tube-shaped conductive rubber molding obtained as described above, and a roller-shaped molded body is obtained. Obtained. In addition to the hot melt adhesive, a vulcanized adhesive can also be used for adhesion between the conductive core material and the conductive rubber molding.

  This molded body was set in a polishing machine (not shown) to which a polishing grindstone (trade name: PT, GC80 HH 23 V4PO, manufactured by Takeken Co., Ltd.) was attached, and the rotation speed was 500 RPM and the feed speed was 500 m. Polishing was performed so that the outer diameter (diameter) became 15 mm per minute to produce a conductive rubber roller (conductive foam rubber roller).

  About the obtained conductive rubber roller, hardness unevenness, resistance unevenness (electric resistance unevenness), and cell (foamed cell) diameter distribution were evaluated as shown below. A method for measuring the temperature of the rubber tube during microwave irradiation (method for measuring the rubber temperature during microwave irradiation) is also shown below. These results are shown in Table 1.

(Measurement method of rubber temperature during microwave irradiation)
Using a fluorescent thermometer (trade name: Fluorescent optical fiber thermometer FL-2000, manufactured by Anritsu Co., Ltd.), the detector of the fluorescent thermometer was inserted into the unvulcanized rubber tube extruded from the extruder, and microwave vulcanization was performed. It is conveyed together with an unvulcanized rubber tube into the furnace of the apparatus (UHF), and the temperature at that time is measured.

(Measurement method of hardness unevenness)
Using a hardness tester (Asker C type, 4.9 N load), the hardness of an arbitrary place in the longitudinal direction of the conductive rubber roller was measured at 90 ° positions in the circumferential direction, and the difference between the maximum value and the minimum value was expressed. . The hardness unevenness is preferably 3 or less.

(Measurement method for uneven electrical resistance of rollers)
The conductive rubber roller was left for 48 hours in an N / N (23 ° C., relative humidity 55%) environment. After that, the shaft body (conductive core material) of the conductive rubber roller is subjected to a load of 4.9 N on one side, and is crimped to a stainless steel drum having an outer diameter of 30 mm and rotated. A voltage of 2 kV was applied between the drum and the electrical resistance was measured. A value obtained by dividing the maximum resistance value at this time by the minimum value was defined as electric resistance unevenness. The electric resistance unevenness is preferably 1.2 or less.

(Confirmation method of cell diameter distribution)
The tube is cut at an arbitrary location, and the cross section thereof is confirmed by a video microscope (manufactured by Keyence Corporation, trade name: Digital Microscope VH-8000). The cell diameter on the outer diameter side and the cell diameter on the inner diameter side are I confirmed the difference. At this time, it is preferable that there is no difference between the cell diameter on the outer diameter side and the cell diameter on the inner diameter side, and “◯” indicates that there is no difference, “X” indicates that there is a difference, and “Δ” indicates that there is a slight difference.

[Examples 2 to 5]
The microwave vulcanization furnace passage time, microwave vulcanizer temperature (heating air temperature) and microwave output were changed as shown in Table 1, and the microwave vulcanization furnace discharge temperature was changed to Table 1. It was set as the temperature shown. Except for this, a conductive rubber roller was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Examples 1-8]
The microwave vulcanization furnace transit time, the microwave vulcanizer temperature (heating air temperature) and the microwave output were changed as shown in Table 2, and the microwave vulcanization furnace discharge temperature was changed to Table 2. It was set as the temperature shown. Except for this, a conductive rubber roller was prepared and evaluated in the same manner as in Example 1. The results are shown in Table 2.

  In Example 1, the rubber temperature was raised to 100 ° C. in 0.5 minutes, and the temperature in the microwave vulcanization furnace was 180 ° C. Good results were obtained in terms of hardness unevenness, resistance unevenness, and cell diameter distribution.

  In Example 2, the temperature of the rubber material was raised to 250 ° C. in 2.0 minutes, and the temperature in the microwave vulcanizing furnace was 230 ° C., so that good values for both hardness unevenness and resistance unevenness could be obtained. The distribution of diameters was also good.

  In Example 3, since the temperature of the rubber material was raised to 240 ° C. in 0.7 minutes and the temperature in the microwave vulcanization furnace was 220 ° C. at that time, good results could be obtained.

  In Example 4, the temperature of the rubber material was raised to 100 ° C. in 2.0 minutes, and the temperature in the microwave vulcanization furnace was 200 ° C., and good results were obtained in terms of foaming, hardness unevenness, and resistance unevenness. I was able to.

  Example 5 is a method for producing a conductive rubber roller of the present invention. The temperature of the rubber material was raised to 250 ° C. in 0.5 minutes and the temperature in the microwave vulcanizing furnace was set to 200 ° C. Good results were obtained for both unevenness and cell diameter distribution.

  Comparative Examples 1 to 3 are cases where the temperature in the microwave vulcanizing furnace was set to 150 ° C. The rubber temperature during microwave irradiation is sufficiently high, but the temperature in the microwave vulcanization furnace is too low at 150 ° C, so the cell diameter distribution of the vulcanization tube is uneven, hardness unevenness, resistance unevenness Both became big values.

  In Comparative Example 4, the temperature in the microwave vulcanization furnace was 200 ° C., but the temperature of the rubber material was raised to 200 ° C. in 0.3 minutes, and the cell diameter distribution was slightly non-uniform. The hardness unevenness was a good value, but the resistance unevenness was a large value of 1.48.

  In Comparative Example 5, since the passage time in the microwave vulcanizing furnace was as long as 2.5 minutes, the hardness unevenness and the resistance unevenness were large, and the cell diameter distribution was not uniform.

  Comparative Examples 6 to 8 are cases where the temperature in the microwave vulcanization furnace was 250 ° C., but the hardness unevenness was a good value because the temperature in the microwave vulcanization furnace was too high, but the resistance unevenness The cell diameter distribution was slightly non-uniform.

  From this result, according to the present invention, it can be seen that the hardness unevenness in the circumferential direction is small and the resistance unevenness in the circumferential direction is 1.2 or less. Furthermore, it turns out that cell diameter distribution becomes uniform.

It is a schematic diagram which shows one form of the electroconductive rubber roller obtained by this invention. It is typical sectional drawing which shows the example of the image forming apparatus (electrophotographic apparatus) using the electroconductive rubber roller obtained by this invention. It is a schematic diagram which shows the example of the vulcanization molding apparatus which can be used for the manufacturing method of the conductive rubber roller of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photosensitive drum 2 ... Charging roller 3 ... Laser beam 4 ... Developing device 5 ... Toner 6 ... Transfer roller 7 ... Transfer material 8 ... Cleaning blade 9 ... Waste toner container 10 ... Fixing device 61 ... Conductive core material 62 ... Foam Rubber layer 11 ... Extruder 12 ... Microwave vulcanizer (UHF)
13. Hot air vulcanizer (HAV)
14 ... take-up machine 15 ... fixed length cutting machine

Claims (4)

In a method for producing a conductive rubber roller having a foam rubber layer on a conductive core material,
A foam rubber layer forming material containing at least one of epichlorohydrin rubber and acrylonitrile butadiene rubber and p, p'-oxybisbenzenesulfonyl hydrazide is heated by microwave irradiation and heated air using a microwave vulcanizing furnace. A vulcanization process to vulcanize,
In the vulcanization step, the foam rubber layer forming material is irradiated with microwaves in heated air at 180 ° C. or higher and 230 ° C. or lower in a microwave vulcanizing furnace, and the foam rubber layer forming material is It is characterized in that the time for passing through the inside of the microwave vulcanizing furnace is 0.5 minutes or more and 2.0 minutes or less, and the temperature at the time of discharge from the microwave vulcanizing furnace is 100 ° C. or more and 250 ° C. or less. A method for manufacturing a conductive rubber roller.   The method according to claim 1, further comprising the step of heating the foam rubber layer forming material vulcanized in the vulcanization step to 150 ° C. or more and 250 ° C. or less using a hot air oven for 1 minute or more and 5 minutes or less. .   A roller for an electrophotographic apparatus, wherein the base layer portion is a conductive rubber roller produced by the method according to claim 1 or 2.   The roller for an electrophotographic apparatus according to claim 3, which is a transfer roller.

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