JP2000304031A - Semi-conductive roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce lines on a picture image caused by a semi-conductive roller, to restrain fluidity of a toner and to improve longevity. SOLUTION: They are semi-conductive rollers 2, 4, 5, 6, 8 having at least one layer of semi-conductive elastic body layer on an outer peripheral surface of an electrically conductive shaft, and at least a surface layer of the semi- conductive elastic body layer is furnished with a copolymer having microdomain structure of a perfluoroalkyl group. Additionally, they are the semi-conductive rollers 2, 4, 5, 6, 8 having at least one layer of the semi-conductive elastic body layer on the outer peripheral surface of the electrically conductive shaft, and a surface of the semi-conductive elastic body layer is covered by a layer furnished with the copolymer containing a perfluoroalkyl group. At this time, a layer furnished with the copolymer containing the perfluoroalkyl group can be furnished with fluorinated olefine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for an electrophotographic apparatus such as a printer, a facsimile, and a copying machine.

[0002]

2. Description of the Related Art An image forming apparatus of a general electrophotographic apparatus (printer, facsimile, copier, etc.) includes a photoconductor device, a charging device, an exposure device, a developing device, a transfer device, a cleaning device, and the like. Is provided. In such an electrophotographic process of an image forming apparatus, a charging device charges a photoconductor device, an exposure device writes an electrostatic latent image on the photoconductor device, and a developing device applies toner on the electrostatic latent image of the photoconductor device. The image is formed on the recording medium by causing the transfer device to transfer the toner image on the electrostatic latent image of the photoconductor device onto the recording medium. The cleaning device removes toner remaining on the photoconductor device without being transferred by the transfer device from the photoconductor device so as not to hinder the next electrophotographic process.

Various structures are used for the charging device, developing device, transfer device and cleaning device in such an image forming apparatus. However, these devices have been used for reasons of simplification of the structure and cost reduction. Is often used with a roller. Each roller is coated with semiconductive elastic rubber, semiconductive foamed sponge, etc., on the outer periphery of a metal shaft, etc., which is a conductive shaft, and a surface coat is applied as necessary. I have.

FIG. 1 is a sectional view showing the structure of an image forming apparatus in an electrophotographic apparatus, and shows an image forming apparatus in a general electrophotographic apparatus as a conventional example. FIG.
The image forming apparatus shown in FIG. 1 includes a photosensitive drum 1, a charging roller 2, an exposure device 3 including an LED head, a developing roller 4, a toner conveying roller 5, a transfer roller 6, a cleaning roller 8, And a toner cartridge TC. Here, the photoconductor device, the charging device, the transfer device, and the cleaning device include the photoconductor drum 1, the charging roller 2, the transfer roller 6, and the cleaning roller 8 illustrated in FIG. 1, respectively. The developing device includes the developing roller 4, the toner transport roller 5, and the developing blade 10 shown in FIG. Further, the photosensitive drum 1, the charging roller 2, the developing roller 4, the toner conveying roller 5, the cleaning roller 8, and the developing blade 1
0 is an electrophotographic cartridge (Electro Photography Ca
rtridge (hereinafter referred to as EP cartridge) is stored in the EC.

Hereinafter, the operation of the image forming apparatus shown in FIG. 1 will be described for the case where the reversal developing method for forming an electrostatic latent image as a negative latent image is used. Alternatively, a normal development method may be used. In this case, the method of exposing the photosensitive drum 1 to form an electrostatic latent image and the polarity of charging the toner, the transfer roller 6 and the cleaning roller 8 are different. However, the configuration and operation of the other devices are the same.

The photosensitive drum 1 includes a conductive base layer of aluminum or the like and a photosensitive layer formed on the outer peripheral surface thereof, and is driven to rotate at a predetermined process speed in the direction of arrow A.
The charging roller 2 rotates in contact with the photosensitive drum 1 in the direction of arrow B to reduce uneven charging potential due to partial adhesion of residual toner and variation in rotation speed. It rotates at a constant peripheral speed ratio. And
A high-voltage charging bias is applied to the conductive shaft of the charging roller 2, and the surface of the photosensitive drum 1 is uniformly charged with the same polarity as the charging roller 2 by the discharge charge at this time.

The exposure device 3 exposes an image portion of the photosensitive drum 1 charged by the charging roller 2 to write an electrostatic latent image. As a result, electric charges of the same polarity as the charging roller 2 remain in portions other than the image portion. The developing roller 4 forms the toner in a uniform thin layer together with the developing blade 10, and uniformly charges the toner to the same polarity as the charging roller 2, thereby forming an image of the electrostatic latent image written on the photosensitive drum 1. The toner is adhered to the portion and developed.

The transfer roller 6 rotates in contact with the photosensitive drum 1 in the direction of arrow E, and a high voltage is applied to the conductive shaft of the transfer roller 6, so that charges of the opposite polarity to the toner are discharged from the transfer roller 6. Then, the toner developed on the photosensitive drum 1 is transferred onto a recording medium 7 conveyed between the photosensitive drum 1 and the transfer roller 6.

The cleaning roller 8 is a photosensitive drum 1
With a constant peripheral speed ratio in the direction of arrow F. Then, during printing, a voltage having a polarity opposite to that of the toner is applied to the conductive shaft of the cleaning roller 8, and even if the voltage is developed on the photosensitive drum 1, the residual voltage remaining on the photosensitive drum 1 without being transferred to the recording medium 7. The toner 9 is temporarily absorbed. Further, at the time of non-printing, a voltage having the same polarity as the toner is applied to the conductive shaft of the cleaning roller 8,
The residual toner 9 once attracted to the cleaning roller 8 is returned to the photosensitive drum 1 and collected by the developing roller 4.

The developing roller 4 rotates in contact with the photosensitive drum 1 in the direction of arrow C with a constant peripheral speed ratio to ensure the recovery of the residual toner 9. The toner transporting roller 5 rotates in the direction of arrow D while rubbing with the developing roller 4, and physically and electrically transports the toner supplied from the toner cartridge TC to the EP cartridge EC to the developing roller 4, and transfers the toner to the toner. A triboelectric charge having the same polarity as that of the charging roller 2 is added. Then, the undeveloped residual toner 9 collected by the developing roller 4 is scraped into the EP cartridge EC. In this way, the residual toner 9 on the photosensitive drum 1 is removed, and the occurrence of an afterimage or the like is prevented.

[0011]

However, the image forming apparatus having the general configuration shown in FIG. 1 has several problems. The first problem is a problem common to all rollers, and a low molecular weight component remaining in a semiconductive elastic rubber or a semiconductive foamed sponge which is a semiconductive elastic material used for each roller. (Hereinafter, referred to as an oligomer).
For example, the oligomer oozing out from the developing roller 4 and the toner transporting roller 5 is mixed with the toner on the developing roller 4 and the toner transporting roller 5 to lower the fluidity of the toner. The toner is not transported smoothly and the toner is still in the EP cartridge EC
Despite the fact that a large amount of toner remains, the image becomes thin as when the remaining amount of toner is small. Further, the charging roller 2, the developing roller 4 in contact with the photosensitive drum 1,
In the transfer roller 6 and the cleaning roller 8,
The oligomer oozing out from each roller adheres to the photosensitive drum 1, and the light emitted from the exposure device 3 to the image portion of the photosensitive drum 1 is blocked, thereby preventing the neutralization of the electric charge.
Since the potential of the image portion does not decrease, the electrostatic latent image is not accurately formed on the photosensitive drum 1 and appears as white streaks on the image transferred to the recording medium 7.

The second problem is that the charging roller 2, the developing roller 4, the transfer roller 6, and the cleaning roller 8, which are in contact with the photosensitive drum 1, adhere to the photosensitive drum 1 in a long-term storage state. This is a problem caused by. For example, a portion where the photoconductor drum 1 and each roller are in contact remains as a mark on the photoconductor drum 1, and the toner is not smoothly transported during development, transfer, cleaning, and the like. A white streak appears in an image portion or a black streak appears in a portion other than the image portion at a pitch on the outer periphery of the photosensitive drum 1 on the transferred image.

In order to prevent the above problems, it is conceivable to apply a fluoropolymer to the surface of each roller or cover each roller with a tube. However, in the method of applying a fluoropolymer, a strong coating layer is formed on the roller surface, and in the method of covering the roller with a tube, the flexibility of the semiconductive elastic body on the outer periphery of the roller is reduced or the surface of the roller is reduced. The uneven shape is crushed, and the original characteristics of the roller cannot be exhibited. That is, an uneven shape is formed on the surface of the roller, which conveys the toner and retains the residual toner 9 adsorbed from the photosensitive drum 1. However, there is a problem that such an ability is lost. is there.

In view of the above, the present invention provides a long-life semiconductive roller which reduces defects such as streaks on an image caused by the semiconductive roller and suppresses a decrease in toner fluidity. The purpose is to:

[0015]

In order to achieve the above object, a semiconductive roller according to the present invention is a semiconductive roller having at least one semiconductive elastic layer on an outer peripheral surface of a conductive shaft. At least the surface layer of the semiconductive elastic layer includes a copolymer having a perfluoroalkyl group microdomain structure.

The semiconductive roller according to the present invention is a semiconductive roller having at least one semiconductive elastic layer on the outer peripheral surface of a conductive shaft, wherein the surface of the semiconductive elastic layer is , A layer comprising a copolymer comprising a perfluoroalkyl group. At this time, the layer including the copolymer containing the perfluoroalkyl group may include a fluorinated olefin.

[0017]

Embodiments of the present invention will be described below in detail. The semiconductive roller according to the present embodiment is used, for example, in the image forming apparatus in the electrophotographic apparatus shown in FIG. That is, the semiconductive roller in the present embodiment can be applied to all of the charging roller 2, the developing roller 4, the toner conveying roller 5, the transfer roller 6, and the cleaning roller 8 of the image forming apparatus shown in FIG. .

(First Embodiment) In the first embodiment, a semiconductive foamed sponge is used as a semiconductive elastic body serving as a base material of a semiconductive roller, and ethylene propylene diene Original copolymer (Ethylene propylene copolymer with some diene components added;
In the case where a copolymer having a microdomain structure of a perfluoroalkyl group (hereinafter, referred to as an Rf group) is added when kneading the dough using silicone or silicone, each of the types used in the image forming apparatus is used. The cleaning roller 8 among the rollers will be described. In the first embodiment, as a copolymer having an Rf-based microdomain structure, a defencer MCF-30 manufactured by Dainippon Ink and Chemicals, Ltd. is used.
0 is used.

Here, the microdomain structure will be described. In general, the compatibility between two types of polymers is poor and often causes phase separation. Therefore, the two types of polymers are used as a polymer chain of a graft copolymer or a block copolymer.
The aggregate of the polymer chains at this time is called a microdomain structure. FIG. 2 is a diagram showing a state of a copolymer having an Rf group microdomain structure according to the first embodiment of the present invention. As shown in FIG. 2, a copolymer 12 having an Rf-based microdomain structure 13 is unevenly distributed on the surface of a base material (semiconductive foamed sponge) 11 of the cleaning roller 8. This is a characteristic property of a copolymer having a microdomain structure.

The semiconductive foamed sponge is mixed with an additive such as carbon when mixing an EPDM or silicone material with a copolymer having an Rf-based microdomain structure, followed by molding and vulcanization. The material is formed as a material for the surface layer of the roller. That is, various additives (heating agent, conductive agent, plasticizer, foaming agent, etc.) and a copolymer having an Rf-based microdomain structure are added to the dough, and the dough, the additive, and the Rf-based microdomain structure are changed. The resulting copolymer is kneaded, molded (primary vulcanized), secondary vulcanized, and polished to complete a semiconductive foamed sponge. The cleaning roller 8 is formed by forming the semiconductive foamed sponge on the outer periphery of the conductive shaft (metal shaft or the like) in this manner.

In order to compare with the cleaning roller 8, a cleaning roller formed of a semiconductive foamed sponge of EPDM or silicone which does not contain a copolymer having an Rf-based microdomain structure is used. The contamination to the photosensitive drum 1 and the adhesion to the photosensitive drum 1 were investigated. Bleed means that oligomers and added plasticizers in the base material seep out to the surface.

The investigation was carried out by printing a 1200 dpi half-pattern on a recording medium using each cleaning roller under the condition of being left for a short period or a long period of time, and evaluating the presence or absence of streaks in the printing result. The evaluation criteria for each evaluation result are as follows, and in such a case, it is assumed that there is no influence of contamination or adhesion. No streaks: あ り Streaks (however, streaks disappear after printing two or less sheets): ○ Streaks (however, streaks disappear after printing three or more sheets): × The results are shown in Table 1.

[0023]

[Table 1]

As shown in Table 1, when the cleaning roller 8 in which the copolymer 12 having the Rf-based microdomain structure 13 is added to the cloth is used, the cleaning time is shorter than when the cleaning roller 8 is not added. Both the white streaks due to the oligomer showing the contaminating property during standing and the white streaks or the black streaks due to the adhesion to the photoreceptor drum 1 showing the cohesive property after standing for a long time show good results. It turns out that it is not affected.

This is because, as shown in FIG. 2, the surface energy of the cleaning roller 8 decreases due to the uneven distribution of the copolymer 12 having the Rf-based microdomain structure 13 existing in the substrate 11 on the surface. , Photosensitive drum 1
This is because the adhesive force between the roller and the cleaning roller 8 is reduced. Further, since the copolymer 12 having the Rf-based microdomain structure 13 present in the base material 11 is unevenly distributed on the surface in a dense state, the gap where the oligomer seeps out from the inside of the base material 11 is filled, and the cleaning roller 8 is formed. This is because the oligomer is prevented from exuding from the photosensitive drum 1 and is prevented from adhering to the photosensitive drum 1, thereby improving the contamination.

In the first embodiment, a cleaning roller formed by molding a semiconductive foamed sponge is used as the semiconductive elastic body, but a cleaning roller formed by molding a semiconductive elastic rubber can also be used. Similarly, the present invention can be applied to a charging roller, a developing roller, a toner conveying roller, and a transfer roller which form a single or multilayer semiconductive elastic body on a conductive shaft. In addition, although EPDM or silicone is used as the material of the semiconductive elastic body, other materials can be used.

(Second Embodiment) In a second embodiment, a semiconductive foamed sponge is used as a semiconductive elastic body serving as a base material of a semiconductive roller, and E.sub.
In the case where a processing agent having a composite system of a copolymer containing an Rf group, a fluorinated olefin, and an acrylic resin is applied to the surface of a base material using PDM or silicone, the toner transport of each roller used in the image forming apparatus is performed. The roller 5 and the cleaning roller 8 will be described. In the second embodiment, as a copolymer containing an Rf group, a defenser TR-200 manufactured by Dainippon Ink and Chemicals, Inc. is used.

FIG. 3 is a view showing a state of a copolymer containing an Rf group according to the second embodiment of the present invention. As shown in FIG. 3, a treatment agent is applied on a base material (semiconductive foamed sponge) 14 of the toner conveying roller 5 or the cleaning roller 8, and the treatment agent includes an acrylic resin 15, a fluorinated olefin 16, A copolymer 17 containing an Rf group is included, and a part of the acrylic resin 15 is unevenly distributed on the base material 14 side, and the copolymer 17 containing an Rf group is unevenly distributed on the surface side of the treatment agent.

The semiconductive foamed sponge is formed by mixing and kneading an additive into an EPDM or silicone material, followed by molding and vulcanization. Thereafter, a treating agent composed of a composite system of the copolymer 17 containing an Rf group, the fluorinated olefin 16 and the acrylic resin 15 is applied to the surface and dried to form a material for the surface layer of the roller. That is, various additives (heating agent, conductive agent, plasticizer, foaming agent, etc.) are added to the dough, the dough and the additives are kneaded, molded (primary vulcanization), secondary vulcanized, and polished. Complete the semi-conductive foam sponge,
A treating agent comprising a composite system of a copolymer 17 containing an Rf group, a fluorinated olefin 16 and an acrylic resin 15 is applied to the completed semiconductive foamed sponge and dried. In the applied treatment agent, the copolymer 17 containing an Rf group is localized on the surface side of the treatment agent, and part of the acrylic resin 15 is localized on the semiconductive foamed sponge side. The semiconductive foamed sponge coated with the processing agent in this manner is
Alternatively, it is formed on the outer periphery of a conductive shaft (such as a metal shaft) of the cleaning roller 8.

In order to compare with the toner conveying roller 5 or the cleaning roller 8, a photosensitive drum formed by bleeding using a toner conveying roller or a cleaning roller formed of EPDM or silicone sponge and not applying a processing agent to the surface. Pollution to 1,
The adhesion to the photosensitive drum 1 and the flowability of the toner were examined.

The investigation was carried out by printing a 1200 dpi half-pattern on a recording medium using each of the toner conveying rollers or the cleaning rollers under the condition of being left for a short period or a long period of time, and evaluating the presence or absence of streaks in the printing result. went. The evaluation criteria for each evaluation result are as follows, and in such a case, it is assumed that there is no influence of contamination or adhesion. No streaks: あ り Streaks (however, streaks disappear after printing two or less sheets): ○ Streaks (however, streaks disappear after printing three or more sheets): × The results are shown in Table 2.

[0032]

[Table 2]

As shown in Table 2, when using a cleaning roller 8 having a surface treated with a treating agent comprising a composite of a copolymer 17 containing an Rf group, a fluorinated olefin 16 and an acrylic resin 15, Compared with the case where the treating agent is not applied, the white streaks due to the oligomer showing the contaminating property when left for a short period of time and the white streaks or black streaks due to the adhesion to the photosensitive drum 1 showing the cohesiveness after leaving for a long period of time Also show good results, indicating that they are not affected by contamination or adhesion. Further, a copolymer 17 containing an Rf group, a fluorinated olefin 16 and an acrylic resin 15
In the case where the toner transport roller 5 having a surface treated with a treating agent composed of a complex system is used, a decrease in toner fluidity can be suppressed as compared with the case where the treating agent is not applied.

This is because, as shown in FIG. 3, the surface energy of the cleaning roller 8 decreases due to the uneven distribution of the copolymer 17 containing the Rf group in the treatment agent applied on the base material 14 on the surface. This is because the adhesion between the photosensitive drum 1 and the cleaning roller 8 is reduced.

The fluorinated olefin 16 in the applied treatment agent completely fills the gap where the oligomer oozes out from the inside of the base material 14 and completely suppresses the ooze out of the oligomer. This is because contamination is improved by preventing the toner from adhering to the photosensitive drum 1. At this time, Rf unevenly distributed on the surface of the treatment agent
The copolymer 17 containing a group also fills the gap where the oligomer seeps out of the inside of the base material 14, blocks the seepage of the oligomer from the cleaning roller 8, prevents the oligomer from sticking to the photosensitive drum 1, and reduces the contamination. Is improved.

Further, in the toner conveying roller 5,
The fluorinated olefin 16 in the applied treatment agent and the copolymer 17 containing an Rf group unevenly distributed on the surface of the treatment agent prevent the oligomer from seeping out from the inside of the base material 14, and the oligomer mixes with the toner. This is because a decrease in the fluidity of the toner can be suppressed by preventing the above.

FIG. 2 shows a second embodiment in which the Rf group-containing copolymer 17 of the treating agent applied on the substrate 14 as shown in FIG. 3 is unevenly distributed on the surface of the treating agent. The difference from the first embodiment in which the copolymer 12 having the microdomain structure 13 of the Rf group in the base material 11 is unevenly distributed on the surface is that the treating agent including the copolymer containing the Rf group is provided. Is applied to the surface of the semiconductive elastic body to completely cover the surface of the semiconductive roller, whereby the oligomer oozing out from the inside can be completely blocked. This is also effective in lowering the toner fluidity.

Here, the acrylic resin 15 in the treating agent is
It functions as an adhesive for bonding the toner transport roller 5 and the processing agent.

In the second embodiment, a semiconductive elastic sponge is used as the semiconductive elastic body of the toner conveying roller and the cleaning roller, but a semiconductive elastic rubber is used. Similarly, the present invention can be applied to a charging roller, a developing roller, and a transfer roller which form a single-layer or multilayer semiconductive elastic body on a conductive shaft. In addition, although EPDM or silicone is used as the material of the semiconductive elastic body, other materials can be used without being limited thereto. Further, the treating agent applied to the surface is not limited to an acrylic resin or a fluorinated olefin, and other materials can be used.

[0040]

As described above, according to the first aspect of the present invention, a semiconductive elastic body formed by adding a copolymer having an Rf-based microdomain structure when mixing an additive into a dough. By using for the surface layer of the semiconductive roller,
Oligomer oozes out of the semiconductive roller when left for a short period of time and adheres to the photosensitive drum, causing white streaks to appear on the image. Both white streaks and black streaks that appear on the image due to the scars remaining on the body drum can be reduced.

According to a second aspect of the present invention, a treatment agent having a copolymer containing an Rf group is applied to a surface of a semiconductive elastic body which is a surface layer of a semiconductive roller, and is left for a short period of time. The white streaks that appear on the image when the oligomer that seeps out of the semiconductive roller adheres to the photosensitive drum in the case,
When left for a long period of time, the semiconductive roller and the photosensitive drum are adhered to each other, and the white streaks and the black streaks that appear on the image due to the traces remaining on the photosensitive drum can be reduced. The second aspect of the present invention is different from the first aspect of the present invention in that a treatment agent comprising a copolymer containing an Rf group is applied to the surface of the semiconductive elastic body to completely cover the surface of the semiconductive roller. By covering, it is possible to completely block oligomers that seep out from the inside. This has an effect that a decrease in toner fluidity can be suppressed.

Further, according to a third aspect of the present invention, a treatment agent having a composite system of a copolymer containing an Rf group and a fluorinated olefin is applied to a surface of a semiconductive elastic body which is a surface layer of the semiconductive roller. By doing so, in addition to the effect of claim 2, the fluorinated olefin blocks the oligomer, and when left for a short period of time, the oligomer that seeps out of the semiconductive roller adheres to the photosensitive drum and appears on the image as white. Muscles,
When left for a long period of time, the semiconductive roller and the photoreceptor drum adhere to each other, leaving traces on the photoreceptor drum and reducing both white and black streaks appearing on the image. This has an effect that a decrease in toner fluidity due to the attached oligomer can be suppressed.

By doing so, it is possible to reduce defects such as streaks on an image caused by the semiconductive roller, and to realize a long-life semiconductive roller in which a decrease in toner fluidity is suppressed. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus in an electrophotographic apparatus.

FIG. 2 is a diagram showing a state of a copolymer having an Rf group microdomain structure according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a state of a copolymer containing an Rf group according to a second embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 1 photoreceptor drum, 2 charging roller, 3 exposure device, 4
Developing roller, 5 toner conveying roller, 6 transfer roller, 7 recording medium, 8 cleaning roller, 9 residual toner, 10 developing blade, 11, 14 base material, 12 R
copolymer having f-group microdomain structure, 13 Rf
Base microdomain structure, 15 acrylic resin, 16
Fluorinated olefin, copolymer containing 17 Rf group

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 15/08 501 G03G 15/08 501D 4F006 15/16 103 15/16 103 4J002 21/10 21/00 312 // C08L 101/16 C08L 101/00 (72) Inventor Takao Mizutani 4-11-11 Shibaura, Minato-ku, Tokyo Inside the offshore company data (72) Inventor Masao Isoda 4-11 Shibaura, Minato-ku, Tokyo No. 22 F-term in the offshore company data (reference) 2H003 BB11 CC05 DD03 2H032 AA05 BA16 BA19 DA02 2H034 BC03 BC09 2H077 AA15 AC04 AD02 AD06 AD31 AD35 AE04 CA19 FA13 FA22 FA25 GA17 3J103 AA02 AA13 AA14 EA11 GA07 GA09 GA02 GA66 GA73 GA74 HA03 HA04 HA12 HA18 HA20 HA53 HA54 HA60 4F006 AA04 AA42 AB19 BA01 BA09 BA11 BA12 CA00 DA04 4J002 BB151 BD122 CP031 FD028 FD1 16 FD327 GM00

Claims (3)

[Claims] 1. A semiconductive roller having at least one semiconductive elastic layer on an outer peripheral surface of a conductive shaft, wherein at least a surface layer of the semiconductive elastic layer is a microdomain of a perfluoroalkyl group. A semi-conductive roller comprising a copolymer having a structure. 2. A semiconductive roller having at least one semiconductive elastic layer on the outer peripheral surface of a conductive shaft, wherein the surface of the semiconductive elastic layer is made of a copolymer containing a perfluoroalkyl group. A semi-conductive roller, which is covered by a layer provided. 3. The semiconductive roller according to claim 2, wherein the layer comprising the copolymer comprising a perfluoroalkyl group comprises a fluorinated olefin.