JP2017198827A - Transfer member, manufacturing method thereof and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer member with a lower electric resistance value, excellent in toner transfer properties to a recording material, and capable of preventing a toner from scattering after transfer.SOLUTION: A transfer member includes a substrate and a conductive elastic layer. The conductive elastic layer includes a hydrin rubber of epichlorohydrin/ethyleneoxide/allyl glycidyl ether ternary copolymer and an acrylonitrile butadiene rubber, and satisfies conditions (1) to (3): (1) a ratio M/(M+M) of the gross mass Mof the hydrin rubber and the gross mass Mof the acrylonitrile butadiene rubber is 0.25-0.40; (2) a molar ratio of an ethyleneoxide unit in the hydrin rubber is 50 mol% or more; and (3) the conductive elastic layer has a sea-island (matrix/domain) structure including a sea (matrix) of the acrylonitrile butadiene rubber and an island (domain) of the hydrin rubber, and a number average diameter of a circumscribed circle being circumscribed about the domain is 0.1-3.0 μm.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transfer member including a substrate and a surface layer containing a conductive conductive elastic layer rubber formed on the outer periphery thereof, a manufacturing method thereof, and an electrophotographic image forming apparatus, which are used in an electrophotographic image forming apparatus.

  In an electrophotographic image forming apparatus, an electrophotographic roller such as a transfer roller for transferring a toner image from the surface of an image carrier to the surface of a recording material is used. As such an electrophotographic roller, there is an electrophotographic roller provided with a conductive base and a surface layer containing conductive rubber formed on the outer peripheral surface thereof.

  In recent electrophotography, speeding up and downsizing have been demanded, and transfer rollers have also been required to have performance corresponding to speeding up and downsizing. That is, since the amount of charge applied per unit time for transferring the toner image to the surface of the recording material increases even at high speed, a reduction in resistance is required. In addition, it is considered that the posture of the recording material can take various states to cope with downsizing, and as a transfer roller, a transfer roller that gives sufficient charge to the recording material so that the toner is stable regardless of the orientation of the recording material Is required.

  Patent Document 1 discloses a conductive material formed by a conductive rubber containing an acrylonitrile butadiene rubber having an acrylonitrile content in a specific range and an epichlorohydrin rubber having an ethylene oxide content of 10 to 40 mol% in a specific ratio. An elastic roller is disclosed. This conductive elastic roller is described as having low electrical resistance unevenness, low hardness, and excellent ozone resistance. Patent Document 2 discloses a conductive elastic roller formed of a conductive rubber containing a specific ratio of acrylonitrile butadiene rubber having an acrylonitrile content in a specific range and a hydrin rubber having an ethylene oxide content of 48 mol% or more. ing. This conductive elastic roller is described as having low electrical resistance and less variation in electrical resistance.

JP-A-11-65269 Japanese Patent No. 3656904

  However, according to the study by the present inventors, in the conductive elastic roller of Patent Document 1, a large amount of epichlorohydrin rubber must be used in order to reduce the resistance, and even in that case, a sufficient charge is applied to the recording material. There were cases where it was not given. Further, according to the study by the present inventors, the conductive elastic roller of Patent Document 2 may not be able to sufficiently reduce the resistance.

  An object of the present invention is to have a low electric resistance value, can impart a sufficient charge to a recording material in electrophotographic image formation, has excellent transferability of toner to the recording material, and suppresses scattering of toner after transfer. Another object of the present invention is to provide a transfer member capable of forming a good image.

The present invention is a transfer member having a base and a conductive elastic layer, the conductive elastic layer comprising an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer hydrin rubber, acrylonitrile butadiene rubber, The transfer member is characterized by satisfying the following conditions (1), (2) and (3).
(1) The ratio M _GECO / (M _GECO + M _NBR ) of the total mass M _{GECO of the} hydrin rubber and the total mass M _NBR of the acrylonitrile butadiene rubber is 0.25 or more and 0.40 or less;
(2) The molar ratio of ethylene oxide units in the hydrin rubber is 50 mol% or more;
(3) The conductive elastic layer has a sea-island (matrix domain) structure composed of the acrylonitrile-butadiene rubber sea (matrix) and the hydrin rubber island (domain), and the number of circumscribed circles circumscribing the domain The average diameter is 0.1 μm or more and 3.0 μm or less.

The present invention also provides
(1) A tube-shaped rubber composition containing a hydrin rubber of an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer, an acrylonitrile butadiene rubber, a vulcanizing agent, a vulcanization accelerator blowing agent, and a blowing agent. The process of forming into a product,
(2) A step of heat-treating the tubular product to obtain a foamed tube by vulcanizing rubber and foaming a foaming agent;
(3) inserting the substrate into the hollow portion of the foamed tube; and
(4) The transfer member manufacturing method including a step of polishing the surface of the foamed tube to expose pores derived from the foam on the surface.

  The present invention also provides an electrophotographic image forming apparatus having the transfer member.

  The transfer member of the present invention has a low electrical resistance value, can impart a sufficient charge to the recording material in electrophotographic image formation, has excellent transferability of toner to the recording material, and suppresses toner scattering after transfer. Can be obtained.

It is the schematic of an example of the transfer member which concerns on this invention. It is the schematic which shows the sea island structure of NBR / GECO, and an island size measuring method. It is the schematic of an example of the apparatus which can be used for formation of the rubber tube comprised from an extruder, a vulcanizer, a take-up machine, and a fixed length cutting machine. 1 is a schematic view of an example of an electrophotographic image forming apparatus according to the present invention.

  Hereinafter, although the form for implementing this invention is demonstrated using a roll-shaped transfer member, the shape of a transfer member is not limited to this. FIG. 1 is an example of a transfer member according to an embodiment of the present invention, and a conductive elastic layer 12 is fixed to the outer periphery of a columnar base 11.

[Substrate]
The substrate is preferably metallic such as aluminum, aluminum alloy, stainless steel, iron or the like. Moreover, in order to improve corrosion resistance and friction resistance, these metals may be subjected to a plating treatment such as chromium or nickel. The shape of the substrate may be hollow or solid, and the outer diameter can be appropriately selected in relation to the image forming apparatus to be mounted, for example, in the range of 4 to 10 mm. Can be mentioned.

[Conductive elastic layer]
The conductive elastic layer includes a hydrin rubber of an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer and an acrylonitrile butadiene rubber. The conductive elastic layer may be a single layer having this layer as the outermost layer, or a plurality of layers in which an inner layer made of an inexpensive and low resistance material made of, for example, acrylonitrile butadiene rubber and conductive carbon exists inside the outermost layer. good. Hereinafter, this outermost layer may be referred to as an “outermost conductive layer”. Further, acrylonitrile butadiene rubber may be referred to as “NBR”, and epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer may be referred to as “GECO”.

The outermost conductive layer is a rubber layer obtained by vulcanizing a rubber composition containing GECO hydrin rubber and NBR, and satisfies the following conditions (1), (2) and (3).
(1) The ratio M _GECO / (M _GECO + M _NBR ) of the total mass M _{GECO of the} hydrin rubber and the total mass M _NBR of the acrylonitrile butadiene rubber is 0.25 or more and 0.40 or less;
(2) The molar ratio of ethylene oxide units in the hydrin rubber is 50 mol% or more;
(3) The conductive elastic layer has a sea-island (matrix domain) structure composed of the acrylonitrile-butadiene rubber sea (matrix) and the hydrin rubber island (domain), and the number of circumscribed circles circumscribing the domain The average diameter is 0.1 μm or more and 3.0 μm or less.

In case where two or more different types of hydrin rubber, if the molar ratio of ethylene oxide units of those hydrin are different, the molar ratio G _EO ethylene oxide units specified in the condition (2) is the ratio hydrin total. For example, when the rubber material is composed of 15 parts by mass of hydrin rubber having a molar ratio of ethylene oxide units of 40 mol%, 15 parts by mass of hydrin rubber having a molar ratio of ethylene oxide units of 60 mol%, and 70 parts by mass of NBR, the ethylene oxide unit of hydrin rubber The molar ratio is 50 mol% by the following calculation.
(40 mol% × 15 mass parts + 60 mol% × 15 mass parts) / (15 mass parts + 15 mass parts) = 50 mol%.

[Electric resistance value]
The electrical resistance value of the transfer member according to the present invention is preferably 6.6 or more and 8.0 or less, and more preferably 7.0 or more and 7.6 or less in LogR. When the electrical resistance value is LogR of 8.0 or less, more preferably 7.6 or less, the toner can be easily transferred without applying a large voltage to charge application from the transfer member to the back side of the recording material. It is preferable from the viewpoint of downsizing. Further, when the electrical resistance value is LogR of 6.6 or more, more preferably 7.0 or more, abnormal discharge from the transfer member to the recording material is less likely to occur, and the degree of freedom of the posture of the recording material is increased. Therefore, it is advantageous for miniaturization of the electrophotographic apparatus.

[Mass ratio of GECO]
In a transfer member using a rubber foam obtained by vulcanizing and foaming a rubber composition containing acrylonitrile butadiene rubber and hydrin rubber as a conductive elastic layer, the mass ratio of hydrin rubber “M _GECO / (M _GECO + M _NBR )” is 0.25. When the ratio is less than or when the molar ratio GE _EO of the ethylene oxide unit of the hydrin rubber is less than 50 mol%, the following problems occur. That is, since only a small amount of the ethylene oxide unit that greatly contributes to ionic conductivity is present in the conductive elastic layer, the electric resistance value of the transfer member is higher than the above range.

Further, when the hydrin rubber mass ratio “M _GECO / (M _GECO + M _NBR )” exceeds 0.40, if the molar ratio G _EO of the ethylene oxide unit of the hydrin rubber is 50 mol% or more, the ionic conductivity is large. Since the contributing ethylene oxide unit is sufficiently present in the foam, a necessary electric resistance value can be obtained, so that there is no problem with toner transferability. However, hydrin rubber having a high content of ethylene oxide units has low compatibility with NBR, and therefore has poor dispersibility in NBR. As a result, the island of hydrin rubber becomes too large in the sea-island structure, and further, the hydrin rubber becomes a sea phase, and charges cannot move smoothly by the mechanism described later. Further, there is a problem in that charge is insufficiently applied to the recording material due to contact or friction at the nip portion, toner is scattered, and image defects occur.

[Sea-island structure]
FIG. 2 shows the microstructure (morphology) of NBR and hydrin rubber in the outermost conductive layer of the present invention. The outermost conductive layer has a sea-island (matrix domain) structure in which the hydrin rubber island phase 22 is dispersed in the NBR sea phase 21, and the size of the hydrin rubber island (domain) is the number average diameter of the circumscribed circle. It is 0.1 μm or more and 3.0 μm or less. The number average diameter of the circumscribed circle is preferably 0.1 μm or more and 1.5 μm or less. Since the shape of the island can take various shapes such as an elliptical shape and an uneven shape, a circumscribed circle that circumscribes the island is created, and the number average diameter obtained from the diameter is used as the size of the island.

  The transfer member installed in the electrophotographic image forming apparatus generates a voltage difference with the recording material by applying a voltage, and is positively added to the back of the recording material at the nip portion where the transfer member and the recording material contact each other. Charge is imparted. Due to the presence of a positive charge on the back of the recording material, toner having a negative charge is held on the surface of the recording material. Therefore, it is important to give more positive charge to the back of the recording material. When the hydrin rubber is in the sea phase in the sea island structure of NBR and hydrin rubber, or when the hydrin rubber island size is larger than 3.0 μm, sufficient charge cannot be imparted to the recording material, and toner is scattered, resulting in poor image quality. Arise. The present inventors make the following assumption as this factor.

  The application of positive charge from the transfer member to the recording material is due to the above-described discharge and injection at the nip portion between the transfer member and the recording material, and the discharge at the gap portion between the transfer member and the recording material before and after the nip. It is conceivable to give an electric charge. At the nip portion between the transfer member and the recording material, a positive charge is applied from the transfer member to the back of the recording material, and negatively charged toner is transferred from the photosensitive member to the surface of the recording material, so that the total charge is stabilized. . On the other hand, when a discharge from the transfer member to the back of the recording material occurs before the nip, a discharge from the photosensitive member to the surface of the recording material occurs due to a potential difference between the recording material and the photosensitive member, and a negative charge is applied. , I think that the charge will be offset. When this pre-nip discharge increases when the positive charge applied to the back side of the recording material should be controlled to a constant level, the charge application to the back side of the recording material at the nip portion decreases. As a result, it is considered that the toner on the surface of the recording material cannot be stably held on the recording material and the toner scatters.

  In order to increase the charge application from the transfer member to the recording material at the nip portion, a method of applying the charge to the recording material by contact or friction in addition to the discharge at the nip can be considered. In order to increase the application of charge to the recording material by contact or friction, it is desired that the charge move smoothly in the outermost conductive layer. As a means for achieving this, it is conceivable that hydrin rubber having a high ethylene oxide molar ratio, which is low resistance in the outermost conductive layer, is highly dispersed in a small island phase. If the size of the island phase is large and the dispersion state of the island phase is poor, the charges cannot move smoothly between the hydrin rubber islands. When the hydrin rubber is in the sea phase, the hydrin rubber having a low ethylene oxide molar ratio must be used in order to keep the electric resistance value of the transfer member within a preferable range, so that the charges cannot move smoothly.

  For this reason, when the size of the hydrin rubber island is larger than 3.0 μm or when the hydrin rubber is in the sea phase, the recording material is not transferred toner because the charge is not sufficiently applied to the recording material by contact or friction at the nip portion. Toner cannot be held and toner scattering occurs. Further, when the size of the hydrin rubber island is less than 0.1 μm, there is no problem in that the charge is imparted to the recording material by contact or friction at the nip portion, but the size of the hydrin rubber island is less than 0.1 μm. It is necessary to apply strong shear during the rubber kneading process. As a result, there arises a problem that the rubber becomes brittle and the durability is lost due to the reason that the molecular chain of the rubber is broken.

[Asker C hardness]
Further, the hardness of the transfer member is not particularly limited, but the Asker C hardness is preferably 20 ° or more and less than 40 °, more preferably 25 ° or more and less than 35 °. If the hardness of the transfer member is too low, the distance between the substrate and the photoconductor is too small, and there is a fear of charge leakage. For example, if the outer diameter of the transfer member is increased, the distance between the substrate and the photoconductor can be maintained even if the hardness of the transfer member is soft. However, since the outer diameter of the transfer member is desired to be small from the viewpoint of miniaturization of the apparatus, the Asker C hardness of the transfer member is preferably 20 ° or more, and more preferably 25 ° or more. On the other hand, if the hardness of the transfer member is too high, the nip area in contact with the recording material is reduced, and the amount of charge applied to the nip portion is reduced. In order to obtain a sufficient nip amount between the transfer member and the recording material, the Asker C hardness of the transfer member is preferably less than 40 °, and more preferably less than 35 °.

[Thickness]
The thickness of the conductive elastic layer is preferably 3.0 mm to 7.0 mm. The thickness of the outermost conductive layer is preferably 1.0 mm to 7.0 mm. If the thickness of the conductive elastic layer is too thin, the distance between the substrate and the photoconductor may be too short, which may cause charge leakage. If the thickness of the outermost conductive layer is too thin, the effect of suppressing toner scattering may not be obtained sufficiently. There is. It is not preferable that the thickness is too thick from the viewpoint of downsizing the apparatus.

[Internal and surface conditions]
The surface state of the outermost conductive layer is not particularly limited, and may be smooth or rough. The outermost conductive layer may be a porous body having a large number of fine pores therein, or may be a non-porous body. As a preferred embodiment, there is an outermost conductive layer in which the surface of the outermost layer is a rough surface having a large number of recesses. A preferred embodiment is an outermost conductive layer which is a porous body and has a rough surface. The concave depth of the surface is preferably 100 to 250 μm. The pore size of the porous body is preferably 200 to 500 μm. These outermost conductive layers can be obtained by forming a foamed rubber tube using a foaming agent, which will be described later, and exposing pores by a polishing process.

[Rubber composition]
[Rubber component]
The rubber composition constituting the outermost conductive layer of the present invention contains both acrylonitrile butadiene rubber (NBR) and epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer (GECO) hydrin rubber as rubber components. Yes. Each of NBR and GECO can be used singly or in combination of two or more.

[GECO]
GECO changes the ease of compatibility with NBR by controlling the molar ratio of each unit of epichlorohydrin / ethylene oxide / allyl glycidyl ether, and the blending ratio of each unit affects the island size of the sea-island structure. Specifically, the higher the molar ratio of epichlorohydrin units compatible with NBR and the lower the molar ratio of ethylene oxide, the finer the GECO is dispersed in the NBR and the smaller the size of the GECO islands. Conversely, the lower the molar ratio of epichlorohydrin units and the higher the ratio of ethylene oxide, the worse the compatibility of GECO with NBR, the poorer the dispersibility, and the larger the island size of GECO. The allyl glycidyl ether unit is an auxiliary unit introduced for sulfur crosslinking, and the blending ratio in GECO is generally a small amount of 2 to 8 mol%. When the blending ratio is within this range, there is no effect on the dispersibility of GECO in NBR. That is, in the sea-island structure in the outermost conductive layer, it is preferable to use GECO having a large content of epichlorohydrin units in order to reduce the island size of GECO.

  On the other hand, a GECO having a low content of ethylene oxide units is a low resistance GECO. Therefore, it is preferable to use GECO having a high content of ethylene oxide units in order to reduce the electrical resistance value of the transfer member. In addition to at least one kind of GECO, the hydrin rubber used can be appropriately selected from epichlorohydrin rubber homopolymer, copolymer of epichlorohydrin and ethylene oxide, etc. in order to obtain desired characteristic values. is there. As the hydrin rubber, a commercially available product or a synthetic product using a known polymerization method can be used. As commercially available products, for example, hydrin rubber manufactured by Nippon Zeon Co., Ltd. and hydrin rubber manufactured by Osaka Soda Co., Ltd. are known.

[Combination of hydrin rubber A and B]
In providing a low-resistance transfer member while reducing the island size of GECO in the sea-island structure, it is preferable to use GECO having a large content of epichlorohydrin units and GECO having a large content of ethylene oxide units in combination. By using these together, the island size of GECO can be easily reduced, and the electrical resistance value of the transfer member can be easily reduced.

  The combination of the two types of GECO may cause the above effect to be attributed to the improved compatibility of GECO with NBR. GECO with a large content of ethylene oxide units is not very good in compatibility with NBR because it is separated from NBR in polarity. On the other hand, GECO with a high content of epichlorohydrin is intermediate between GECO and NBR with a high content of ethylene oxide units, and is considered to function like a compatibilizer. Therefore, it is considered that by mixing the above two types of GECO, an island structure is formed in which GECO with a high content of epichlorohydrin units is covered around GECO with a high content of ethylene oxide units. As a result, it is considered that GECO having a large content of ethylene oxide units has improved dispersibility in NBR despite having a small electric resistance value.

  A specific example of a combination of two or more types of GECO for the purpose of manifesting the above combined effect includes a combination that satisfies the following conditions.

The hydrin rubber is a mixture of two or more types of hydrin rubber, and among the hydrin rubbers having the first and second largest mass ratios in the mixture, the hydrin rubber having the higher molar ratio of ethylene oxide units is the molar ratio of hydrin rubber A and ethylene oxide units. When the hydrin rubber having a smaller amount of hydrin is used as the hydrin rubber B, the following conditions (1), (2) and (3) are satisfied.
(1) The molar ratio A _EO of ethylene oxide units in the hydrin rubber A is 60 mol% or more and 90 mol% or less,
(2) The mass ratio of hydrin rubber A in the mixture is 0.30 or more and 0.85 or less,
(3) The molar ratio B _EO of the ethylene oxide unit of the hydrin rubber B to the molar ratio A _EO of the ethylene oxide unit in the hydrin rubber A is 80% or less.

If hydrin A molar ratio A _EO ethylene oxide units in is more than 60 mol%, can be a small amount by the transfer member by when the hydrin A combination with other GECO low resistance. For this reason, in the hydrin rubber mixture, the content ratio of hydrin rubber B having high compatibility with NBR can be increased, and as a result, the island size of GECO can be easily reduced. When the molar ratio A _EO ethylene oxide units in the hydrin A is less than 90 mol%, since many epichlorohydrin unit having rubber properties, in processing a rubber composition into the outermost conductive layer, rubber properties coercive Easy to sag.

  When the mass ratio of hydrin rubber A in the hydrin rubber mixture is 0.30 or more, it is easy to make the transfer member low resistance. Therefore, hydrin rubber B can be used with a high compatibility with NBR, and the GECO island can be made small. Easy to do. Moreover, when the mass ratio of the hydrin rubber A in the hydrin rubber mixture is 0.85 or less, it is easy to reduce the size of the GECO island. This is considered to be because it becomes easy to cover the outside of the hydrin rubber A with the hydrin rubber B.

When the molar ratio B _EO of the ethylene oxide unit of the hydrin rubber B is 80% or less with respect to the molar ratio A _EO of the ethylene oxide unit of the hydrin rubber A, the properties of the hydrin rubber A and the hydrin rubber B are sufficiently separated. Can be covered with hydrin rubber B.

  When the hydrin rubber A and hydrin rubber B used in combination satisfy the above (1) to (3), it is easy to reduce the electrical resistance value of the transfer member and to reduce the size of the GECO island.

[NBR]
Although it does not specifically limit as NBR, The content of 15 mass%-50 mass% of acrylonitrile content generally known can be used. More preferably, NBR having an acrylonitrile content of 18% by mass or more and 40% by mass or less is used. Since acrylonitrile is a polar group, it affects the compatibility between NBR and GECO, and also affects the mobility of the polymer molecular chains of NBR. If the acrylonitrile content in NBR is 18% by mass or more, the compatibility between NBR and GECO is improved, and the island size is easily reduced. In addition, when the acrylonitrile content in NBR is 40% by mass or less, the outermost conductive layer can be easily softened, so that the hardness of the transfer member can be easily set within a preferable range. NBR having an acrylonitrile content within the above range has a good balance between both factors (the size of the island and the hardness of the transfer member). A commercial item etc. can be used as NBR. As a commercially available product, for example, NBR manufactured by Nippon Zeon Co., Ltd. is known.

[Manufacture of transfer members]
Although the manufacturing method of the transcription | transfer member which concerns on the said invention is not specifically limited, For example, the method containing the following processes (1)-(4) is mentioned.
(1) A rubber composition containing a hydrin rubber of an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer, an acrylonitrile butadiene rubber, a vulcanizing agent, a vulcanization accelerator, and a foaming agent in a tubular shape. Molding process,
(2) A step of heat-treating the tubular product to obtain a foamed tube by vulcanizing rubber and foaming a foaming agent;
(3) A step of inserting a substrate into the hollow portion of the foamed tube, and (4) a step of polishing the surface of the foamed tube to expose pores derived from the foaming on the surface.

  An example of a method for manufacturing the transfer member will be described with reference to the apparatus shown in FIG.

  A rubber component, a vulcanization aid, and additives as necessary are kneaded as a rubber composition using a closed kneader such as a Banbury mixer or a kneader. Thereafter, using an open roll, a foaming agent, a vulcanizing agent, a vulcanization accelerator and the like are added to the kneaded product and kneaded. Thereafter, the kneaded product is formed into a ribbon shape by a ribbon forming and dispensing machine. This molded product is put into the extruder 31, and the rubber tube is extruded.

  Next, the obtained rubber tube is vulcanized and foamed. Vulcanization and foaming can be performed by known methods such as a microwave vulcanizer, a hot air vulcanizer, an electric furnace, and a vulcanizer. It is preferable to use a vulcanizer including the microwave vulcanizer 32, vulcanize and foam with the microwave vulcanizer, and then further vulcanize and foam with the hot air vulcanizer 33. When vulcanized and foamed by a vulcanizing apparatus including a microwave vulcanizing apparatus, uniform heat conduction to the rubber tube is possible, so that it is easy to obtain a desired foamed elastic layer in accordance with the material characteristics.

  The vulcanized and foamed rubber tube is conveyed from the inside of the microwave vulcanizing device 32 and the hot air vulcanizing device 33 by the take-out machine 34, and is cut to a desired size by the regular cutting machine 35. The rubber tube may be cut before or after vulcanization and foaming.

  The substrate is press-fitted into the hollow portion of the rubber tube thus obtained. The method for fixing the rubber tube and the substrate includes a method of applying a conductive adhesive to the substrate and a method of press-fitting a substrate having an outer diameter larger than the inner diameter of the rubber tube, and may be selected as appropriate. Furthermore, after press-fitting the substrate, both ends of the rubber tube may be cut to a desired length as necessary. Usually, the length of the substrate is set to be equal to or longer than the length of the rubber tube, or after the rubber tube is cut, from the both ends of the rubber tube (conductive elastic layer 12) as shown in FIG. The part is exposed.

  The surface of the rubber tube into which the substrate is press-fitted is polished by a polishing machine, and a number of holes formed in the rubber tube are exposed on the surface of the rubber tube. In this way, a transfer member is produced in which a conductive elastic layer having a rough surface is formed on the outer periphery of the substrate.

[Vulcanizing agent / Vulcanization accelerator]
In the rubber composition used for forming the outermost conductive layer of the present invention, sulfur or the like can be contained as a vulcanizing agent. Although the compounding quantity is not specifically limited, Preferably it is 2.5 mass parts or more and 4.0 mass parts or less of sulfur with respect to 100 mass parts of rubber components. If the sulfur is 2.5 parts by mass or more, it can be sufficiently vulcanized, and aggregation of unvulcanized GECO can be avoided during the vulcanization. If the sulfur content is 4.0 parts by mass or less, the hardness of the outermost conductive layer does not become too high, and transfer omission during image formation can be prevented.

  The rubber composition may contain a thiuram, thiazole, guanidine, sulfenamide, dithiocarbamate, thiourea, etc. as a vulcanization accelerator. A combination of a thiuram vulcanization accelerator and a thiazole vulcanization accelerator is particularly useful because it has a high effect as a vulcanization accelerator for vulcanization of NBR and GECO.

  Examples of thiuram-based vulcanization accelerators include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), tetrabutylthiuram disulfide (TBTD), and tetraoctylthiuram disulfide (TOT). TETD is preferable in consideration of the reactivity as a vulcanization accelerator and environmental safety. Examples of thiazole vulcanization accelerators include 2-mercaptobenzothiazole (MBT), dibenzothiazolyl disulfide (MBTS), and 2-mercaptobenzothiazole zinc salt (ZnMBT). MBTS is preferred because of its high reactivity as a vulcanization accelerator and low scorch properties.

Since the vulcanization speed varies depending on the blending ratio of the vulcanization accelerator, the blending quantity of the vulcanization accelerator as well as the blending quantity of the vulcanizing agent affects the island size of the sea-island structure. It is preferable that the blending ratio (molar ratio) of sulfur as a vulcanizing agent, thiuram vulcanizing accelerator as a vulcanizing accelerator, and thiazole vulcanizing accelerator satisfy the condition of the following formula (1) (1 ) 0.5 <VA ₁ / (VA ₂ + VA ₃ ) <3.0
VA ₁ : sulfur content (mole)
VA ₂ : blending amount (mole) of thiuram vulcanization accelerator
VA ₃ : blending amount (mole) of thiazole vulcanization accelerator.

  If the “sulfur / vulcanization accelerator” value in the above formula is larger than 0.5, sufficient vulcanization can be achieved, and aggregation of unvulcanized GECO during vulcanization can be avoided. The size can be controlled moderately. If the “sulfur / vulcanization accelerator” value in the above formula is less than 3.0, the hardness of the outermost conductive layer does not become too high, and transfer omission during image formation can be prevented. That is, if the relationship of the above mathematical formula is satisfied, both the size of the island and the hardness of the outermost conductive layer can be controlled within a preferable range.

[Vulcanization aid]
The rubber composition used for forming the outermost conductive layer of the present invention can contain a vulcanization aid. Examples of the vulcanization aid include zinc oxide, zinc stearate, stearic acid and the like, but it is preferable to contain zinc stearate and stearic acid. Zinc stearate is preferred from the viewpoint of the stability of the electrical resistance value when the transfer member is stored for a long period of time. Further, when stearic acid is contained, sticking to a roll is reduced during kneading of the rubber composition, and the processability is excellent.

[Foaming agent]
The rubber composition used for forming the outermost conductive layer of the present invention appropriately contains azodicarbonamide, sodium hydrogen carbonate, p, p′-oxybisbenzenesulfonylhydrazide (OBSH), etc. as a foaming agent. Can do. The foaming agent is not particularly limited, but OBSH is preferable in consideration of the temporal variability of the electrical resistance value of the transfer member and the uniformity of the cell diameter of the pores formed in the outermost conductive layer. The blending amount of OBSH is not particularly limited, and by blending 2.0 parts by mass or more per 100 parts by mass of the rubber component, a stable foamed state is obtained, and the hardness of the outermost conductive layer is stabilized.

[Other additives]
In addition, the rubber composition may contain carbon black, calcium carbonate, and the like as long as the functions of the substances contained in the composition are not impaired.

[Electrophotographic image forming apparatus]
The transfer member according to the present invention can be used by being incorporated in an electrophotographic image forming apparatus. An example of the electrophotographic image forming apparatus is shown in FIG. 4 in which the transfer member is a transfer roller. In FIG. 4, the surface of the photosensitive drum 601 is uniformly charged by a charging roller 602 as a contact charging member. The charging roller 602 is disposed in contact with the surface of the photosensitive drum 601 and is driven to rotate as the photosensitive drum rotates in the arrow R1 direction. An oscillating voltage (AC voltage VAC + DC voltage VDC) is applied to the charging roller by a charging bias application power source (high voltage power source), whereby the surface of the photosensitive drum is uniformly charged to −600 V (dark portion potential Vd). The The surface of the photosensitive drum after charging is scanned and exposed by a laser beam 603 output from a laser scanner and reflected by a mirror, that is, a laser beam 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 target image information (bright part Vl = −150 V) is formed on the surface of the photosensitive drum. The electrostatic latent image is negatively charged with a developing bias applied to the developing roller 604 of the developing device, and is reversely developed as a toner image.

  On the other hand, the transfer material P such as paper fed from the paper supply unit 609 is guided by the transfer guide, and is transferred to the transfer unit (transfer nip unit) between the photosensitive drum 601 and the transfer roller 605 on the photosensitive drum. The toner image is supplied so as to match the timing. The toner image on the photosensitive drum is transferred to the surface of the transfer material supplied to the transfer unit by the transfer bias applied to the transfer roller by the transfer bias application power source. At this time, toner remaining on the surface of the photosensitive drum without being transferred to the transfer material (residual toner) is removed by the cleaning blade 607 of the cleaning device. The transfer material that has passed through the transfer portion is separated from the photosensitive drum and introduced into a fixing device (not shown), where the toner image is subjected to fixing processing, and is discharged to the outside of the image forming apparatus main body as an image formed product (print). Is done.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in detail, this invention is not limited to this. Tables 6 and 7 show details of various materials used in Examples and Comparative Examples.

[Example 1]
1. Preparation of rubber composition Filler 1 and vulcanization aid 1 were added to the following rubber component 1, and these were added to a 7-liter sealed kneader (trade name: WDS7-30, manufactured by Moriyama Corporation). The rubber composition was obtained after being put into the interior and kneaded for 7 minutes at a rotor speed of 30 rpm.

<Rubber component 1>
68 parts by mass of acrylonitrile butadiene rubber (trade name: Nipol DN401LL, Nippon Zeon Co., Ltd.)
16 parts by mass of epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer (trade name: EPION301, Osaka Soda Co., Ltd.) containing 74 mol% of ethylene oxide,
16 parts by mass of an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer (trade name: Epichromer CG, Daiso Co., Ltd.) containing 41 mol% of ethylene oxide.

<Filler 1>
35 parts by mass of carbon black (trade name: Asahi # 35G Asahi Carbon Co., Ltd.).

<Vulcanization aid 1>
Zinc stearate (trade name: zinc stearate, NOF Corporation) 3.0 parts by mass,
Stearic acid (trade name: Tsubaki stearate, NOF Corporation) 1.0 part by mass.

  Next, the following foaming agent 1, vulcanizing agent 1 and vulcanization accelerator 1 were added to the rubber composition. The obtained rubber composition was cooled for 15 minutes using an open roll (device name: 12 inch open roll, manufactured by Kansai Roll Co., Ltd.) while maintaining the temperature of the rubber composition at 80 ° C. or lower. Kneaded and dispersed. Finally, the shape of the rubber composition was adjusted to a ribbon shape to prepare an unvulcanized rubber composition for the outermost layer of the conductive elastic layer.

<Vulcanizing agent 1>
Sulfur (trade name: Sulfax PMC, Tsurumi Chemical Co., Ltd.) 3.0 parts by mass.

<Vulcanization accelerator 1>
Tetraethylthiuram disulfide (trade name: Noxeller TET-G, Ouchi Shinsei Chemical Co., Ltd.) 2.0 parts by mass,
1.5 parts by mass of dibenzothiazyl disulfide (trade name: Noxeller DM-P, Ouchi Shinsei Chemical Co., Ltd.)

<Foaming agent 1>
OBSH (trade name: Neoselbon N # 1000M, Eiwa Kasei Kogyo Co., Ltd.) 2.5 parts by mass.

2. Production of Transfer Member (Transfer Roller) A tubular foamed elastic layer was produced using the production apparatus shown in FIG. First, the ribbon-like unvulcanized rubber composition was supplied to a rubber extruder (device name: 60 mm uniaxial vent rubber extruder, manufactured by Mitsuba Corporation) and extruded into a tube shape. Next, a vulcanizer (device name: 3.0 kW microwave continuous rubber) including a microwave vulcanizer 32 (device name: special type 3 kW microwave vulcanizer, manufactured by Micro Electronics Co., Ltd., maximum output 3.0 kW) The tube-like material was vulcanized and foamed by a vulcanization line (manufactured by Micro Electronics Co., Ltd.) to produce a rubber tube. The microwave vulcanizer had a frequency of 2450 ± 50 MHz and an output of 0.6 kW, and the furnace temperature was set to 200 ° C. After vulcanization and foaming in the microwave vulcanization apparatus, vulcanization and foaming were further performed in a hot air vulcanization apparatus 33 in which the furnace temperature was set to 200 ° C. The tube outer diameter after vulcanization and foaming was 14.0 mm, and the inner diameter was 4.0 mm. The rubber tube was conveyed at a speed of 2.0 m / min by the take-up machine 34 in the microwave vulcanizer and the hot air vulcanizer. After vulcanization and foaming, the rubber tube was cut into a length of 250 mm using a regular cutter 35.

  Next, a stainless steel substrate having an outer diameter of 5 mm and a length of 240 mm was press-fitted into the hollow portion of the rubber tube, and then both ends of the rubber tube were cut to obtain a member having a rubber length of 216 mm. The outer peripheral surface of the member is polished so that the outer diameter is 12.5 mm at a rotational speed of 1800 rpm, a feed speed of 800 mm / min, and a conductive member (conductive elastic layer) is provided on the outer periphery of the substrate. . 1 was produced.

3. 3. Measurement of physical properties of transfer member (transfer roller) 3-1. Sea-island structure Transfer member No. The conductive elastic layer was cut out from 1 at a size of 3 mm square, and observed with a scanning electron microscope (Ultraplus, hereinafter referred to as “SEM”) at an acceleration voltage of 1 kV and a magnification of 5000 times. Sea-island structure and island size were evaluated from the images. Furthermore, using an energy dispersive X-ray microanalyzer (Thermo Fisher Scientific, Noran System 7, hereinafter referred to as “EDS”), an island portion is observed at an acceleration voltage of 6 kV, a magnification of 5000 times, and a working distance of 8 mm. did. When a chlorine atom contained in hydrin but not in NBR was confirmed, it was determined that the island portion was hydrin rubber. The size of the island was observed by SEM, 30 hydrin rubber islands in a range of 17.5 μm in length × 25.0 μm in width were selected at random, and the diameter of the circumscribed circle was measured. The number average value of the diameters of 30 circumscribed circles was used as the island size.

4). Measurement of electric resistance value of transfer member (transfer roller) 1 was allowed to stand for 24 hours in an environment at a temperature of 23 ° C. and a relative humidity of 55%, and then the electrical resistance value was measured in the same environment. The transfer member is pressure-bonded to a stainless steel drum having an outer diameter of 30 mm, a load of 500 g (1 kg in total on both sides) is applied to both sides of the base of the transfer member, and the stainless steel drum is rotated at a speed of 30 rpm. The transfer member was driven to rotate. In this state, a voltage of 1000 V was applied between the base and the stainless steel drum for 3 seconds, and the current value flowing at that time was measured. From the current value, the electrical resistance value was calculated according to Ohm's law. The electrical resistance value was the average value for the last 2 seconds.

5. Asker C hardness of transfer member (transfer roller) After leaving No. 1 in an environment at a temperature of 23 ° C. and a relative humidity of 55% for 24 hours, the Asker C hardness was measured in the same environment. In a state where the transfer member is received by the bearing, in accordance with JIS K7312 and S6050, the surface of the conductive elastic layer is loaded with a total pressure of 500 g and an Asker C-type spring hardness tester (trade name: CL-150L, polymer meter The pusher needle (made by Co., Ltd.) was pressed, the value 5 seconds after contact with the member was read, and the Asker C hardness was measured. Note that, at the central portion of the transfer member and at a total of three positions of 4 cm from both ends, three positions at positions where the transfer member was rotated by 120 degrees, that is, a total of nine positions were used as measurement points. The average value of the measured values was defined as Asker C hardness of the transfer member. The measurement results of Asker C hardness were displayed according to the following criteria.
AA: Asker C hardness is 25 ° or more and less than 35 °.
A: Asker C hardness is 20 ° or more and less than 25 °, or 35 ° or more and less than 40 °.
B: Asker C hardness is 15 ° or more and less than 20 °, or 40 ° or more and less than 45 °.
C: Asker C hardness is less than 15 ° or 45 ° or more.

6). Image evaluation An electrophotographic laser beam printer (trade name: Laser Jet P1606dn, manufactured by Hewlett-Packard) was modified to a printing speed of 30 ppm with A4 paper, and a line perpendicular to the line passing through the center of the transfer member / photosensitive drum The recording material was modified so that the recording material entered from an angle inclined by 20 ° with respect to the photosensitive drum. The response to high-speed machines was evaluated by increasing the printing speed, and the approaching angle of the recording material was set to be an adverse angle with respect to the toner scattering, so that the response to the miniaturization was evaluated.

  Transfer member No. 1 was left for 24 hours or more in a low-temperature and low-humidity environment with a temperature of 15 ° C. and a relative humidity of 10%. Next, this transfer member was incorporated in the modified image evaluation machine as a transfer roller, and image evaluation was performed with an initial image in a low temperature and low humidity environment at a temperature of 15 ° C. and a relative humidity of 10%. The toner transferability was judged from the density of the obtained solid black image, and the scattering of the toner was visually examined from the lattice image, and evaluated according to the following criteria.

6-1. Toner transfer property AA: The toner transfer property is very good.
A: Transferability of toner is good.
B: Transferability of toner is slightly inferior.
C: Toner transferability is poor.
D: Toner transferability is poor.
E: Toner transferability is extremely poor.

6-2. Toner scattering AA: No toner scattering is observed.
A: Almost no toner scattering is observed.
B: Toner scattering is slightly observed.
C: Scattering of toner is observed, but it does not impair image quality.
D: Scattering of toner is recognized and image quality is slightly impaired.
E: Remarkable scattering of toner is recognized and image quality is impaired.

6-3. Overall evaluation AA: All evaluations of transferability, scattering, and hardness are AA or A.
A: At least one of the evaluations of transferability, scattering, and hardness includes B and / or C, and D and E are not included in any evaluation.
B: At least one of the evaluations of transferability and scattering includes D or E.

7). Evaluation result Transfer member No. 1 is a member physical property, electrical resistance value (LogR) 7.30, sea island structure is NBR sea phase and hydrin island phase, the number average diameter of circumscribed circle of the island is 0.7μm, Asker C hardness is 31 ° Met. Both the evaluation of toner transferability and the evaluation of toner scattering were AA.
Tables 1 to 5 show the raw material blending amounts and evaluation results of Example 1, and the raw material blending amounts and evaluation results of the following Examples 2-35 and Comparative Examples 1-4.

[Examples 2-35 and Comparative Examples 1-4]
In the same manner as in Example 1, except that any one or more of the types of rubber components, the types of vulcanization aids, vulcanizing agents, vulcanization accelerators, and usage amounts were changed, transfer member Nos. 2-No. 35 (Examples 2 to 35) and C1-No. C4 (Comparative Examples 1 to 4) was obtained.

  In Examples 2 to 11, the type and blending amount of GECO were changed so that the average EO mol%, the mass ratio of hydrin rubber A, and the EO molar ratio of hydrin rubber B / hydrin rubber A were changed. In Examples 12 to 13, three types of GECO were used. In Examples 14 to 15, the parts of sulfur were 2.5 parts by mass and 4 parts by mass, respectively. In Example 16, only one GECO having an EO mol% of 68 mol% was used. In Example 17, hydrin rubber A having an EO mol% of 56 mol% was used. In Example 18, a combination of hydrin rubber A and hydrin rubber B in which the EO molar ratio of hydrin rubber B / hydrin rubber A was 88% was used. Moreover, in Examples 16-18, the mass ratio of acrylonitrile was 42.5 mass% as NBR, S / TET + DM molar ratio was mix | blended in the ratio of 3.06, and the part of sulfur was 5 mass parts. In Examples 19 to 25, NBR having an acrylonitrile mass ratio of 42.5 mass% was used, and the S / TET + DM molar ratio was blended at a ratio of 3.06, and the sulfur part was 5 mass parts. In Examples 26-29, S / TET + DM molar ratio was mix | blended in the ratio of 3.06, and the part of sulfur was 5 mass parts. In Examples 30 to 34, the number of parts of sulfur was 5 parts by mass, 2 parts by mass, or 4.5 parts by mass. In Example 35, the S / TET + DM molar ratio was blended at a ratio of 0.49, and the sulfur part was 2 parts by mass.

In Comparative Examples 1, 3, and 4, hydrin rubber having “M _GECO / (M _GECO + M _NBR )” values of 0.20, 0.50, and 0.42, respectively, was used. In Comparative Example 2, hydrin rubber having a molar ratio of ethylene oxide units in the hydrin rubber of 35 mol% was used.

各ローラの物性値および評価結果を表１〜表５に示す。実施例１〜３５においては画像における転写性、飛び散りに問題がなく良好な画像が得られた。その中でも、実施例１〜１５においては、抵抗値、海島の大きさ、硬度の各値が好ましい範囲であり、画像評価の結果も特に良好であった。一方、比較例１では、ゴム成分中におけるヒドリンゴムの配合比率が少なく、比較例２では、ヒドリンゴム中のエチレンオキサイド量が少ない為、抵抗値がそれぞれＬｏｇＲで８.１１、８．６１と高抵抗であり転写性が悪い。これらについては転写性が悪い為、転写後の評価となる飛び散りについては評価できなかった。比較例３では、ゴム成分中におけるヒドリンゴムの配合比率が多過ぎる為に、ヒドリンが海相の海島構造が形成され、比較例４では、ゴム成分中におけるヒドリンゴムの配合比率が多く、ヒドリンゴムの島のサイズが大きくなった。これらのローラを使用した場合は転写後のトナー保持能力が弱く、飛び散りが発生した。

Tables 1 to 5 show physical property values and evaluation results of each roller. In Examples 1 to 35, there was no problem in transferability and scattering in images, and good images were obtained. Among them, in Examples 1 to 15, the resistance value, the size of the sea island, and the hardness were within the preferable ranges, and the results of the image evaluation were particularly good. On the other hand, in Comparative Example 1, since the blending ratio of the hydrin rubber in the rubber component is small, and in Comparative Example 2, the amount of ethylene oxide in the hydrin rubber is small. There is poor transferability. Since the transferability of these was poor, it was not possible to evaluate the scattering that would be evaluated after transfer. In Comparative Example 3, since the blending ratio of hydrin rubber in the rubber component is too large, a sea-island structure of hydrin is formed in the rubber component. In Comparative Example 4, the blending ratio of hydrin rubber in the rubber component is large. The size has increased. When these rollers were used, the toner holding ability after transfer was weak and scattering occurred.

11 ... Base 12 ... Conductive elastic layer 21 ... NBR sea phase 22 ... Hydrin rubber island phase 23 ... Island phase circumscribed circle

Claims (12)

A transfer member having a base and a conductive elastic layer,
The conductive elastic layer includes an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer hydrin rubber, and acrylonitrile butadiene rubber;
A transfer member satisfying the following conditions (1), (2) and (3):
(1) The ratio M _GECO / (M _GECO + M _NBR ) of the total mass M _{GECO of the} hydrin rubber and the total mass M _NBR of the acrylonitrile butadiene rubber is 0.25 or more and 0.40 or less;
(2) The molar ratio of ethylene oxide units in the hydrin rubber is 50 mol% or more;
(3) The conductive elastic layer has a sea-island (matrix domain) structure composed of the acrylonitrile-butadiene rubber sea (matrix) and the hydrin rubber island (domain), and the number of circumscribed circles circumscribing the domain Average diameter is 0.1 μm or more and 3.0 μm or less. The hydrin rubber is a mixture of two or more types of hydrin rubber, and among the hydrin rubbers having the first and second largest mass ratios in the mixture, the hydrin rubber having the higher molar ratio of ethylene oxide units is the mole of hydrin rubber A and ethylene oxide unit. The transfer member according to claim 1, which satisfies the following conditions (1), (2) and (3) when the hydrin rubber having a smaller ratio is hydrin rubber B:
(1) The molar ratio of ethylene oxide units in the hydrin rubber A is 60 mol% or more and 90 mol% or less,
(2) The mass ratio of hydrin rubber A in the mixture is 0.30 or more and 0.85 or less,
(3) The molar ratio of the ethylene oxide unit of the hydrin rubber B to the molar ratio of the ethylene oxide unit in the hydrin rubber A is 80% or less.   The transfer member according to claim 1, wherein the number average diameter of the circumscribed circle is 0.1 μm or more and 1.5 μm or less.   The transfer member according to claim 1, wherein a content of acrylonitrile in the acrylonitrile butadiene rubber is 18% by mass or more and 40% by mass or less.   The transfer member according to claim 1, wherein the surface of the conductive elastic layer is a rough surface having a large number of recesses.   The transfer member according to claim 1, wherein the conductive elastic layer is a porous body. The rubber layer is obtained by vulcanizing and foaming a rubber composition containing sulfur as a vulcanizing agent and a thiuram vulcanizing accelerator and a thiazole vulcanizing accelerator as vulcanization accelerators. The transfer member according to any one of claims 1 to 6, wherein a blending ratio (molar ratio) of each vulcanization accelerator satisfies a condition of the following mathematical formula (1):
Equation _{(1) 0.5 <VA 1 /} (VA 2 + VA 3) <3.0
VA ₁ : sulfur content (mole)
VA ₂ : blending amount (mole) of thiuram vulcanization accelerator
VA ₃ : blending amount (mole) of thiazole vulcanization accelerator.   The transfer member according to claim 7, wherein a blending amount of the sulfur with respect to 100 parts by mass of the rubber component is 2.5 parts by mass or more and 4.0 parts by mass or less. A step of forming a rubber composition containing a hydrin rubber of an epichlorohydrin / ethylene oxide / allyl glycidyl ether terpolymer, an acrylonitrile butadiene rubber, a vulcanizing agent, a vulcanization accelerator, and a foaming agent into a tube-shaped material. ,
A step of heat-treating the tubular material to obtain a foamed tube by vulcanizing rubber and foaming a foaming agent;
Inserting a base into the hollow portion of the foamed tube; and polishing the surface of the foamed tube to expose pores derived from the foam on the surface;
The manufacturing method of the transfer member of any one of Claims 1-6 which has these. The rubber composition contains sulfur as a vulcanizing agent, a thiuram vulcanization accelerator and a thiazole vulcanization accelerator as vulcanization accelerators, and a mixing ratio of sulfur and vulcanization accelerator in the rubber composition ( The manufacturing method of the transfer member according to claim 9, wherein the molar ratio satisfies the condition of the following mathematical formula (1):
Equation _{(1) 0.5 <VA 1 /} (VA 2 + VA 3) <3.0
VA ₁ : sulfur content (mole)
VA ₂ : blending amount (mole) of thiuram vulcanization accelerator
VA ₃ : blending amount (mole) of thiazole vulcanization accelerator.   The method for producing a transfer member according to claim 10, wherein a blending amount of the sulfur with respect to 100 parts by mass of the rubber component is 2.5 parts by mass or more and 4.0 parts by mass or less. An electrophotographic image forming apparatus having the transfer member according to claim 1.

Images