JP2018151615A - Member for electrophotography, transfer member, and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member for electrophotography having an ion conductive elastic layer in which an environmental dependency of electric resistance is small, and the electric resistance hardly fluctuates even after long-term use.SOLUTION: There is provided a member for electrophotography having a substrate and a conductive elastic layer on the substrate, therein the elastic layer contains a sulfur vulcanizate of rubber mixture containing following (A) to (C) components, and (A)NBR, (B)GCO, (C)GECO, and the sulfur vulcanizate have a matrix/domain structure with a matrix including a structure derived from acrylonitrile of the (A) components and a domain including a structure derived from epichlorohydrin of the (B) components and the (C) components, and a content ratio of the (A) components to the total sum of content of the (A) to (C) components in the rubber mixture is 50 to 80 mass%, and a content ratio of the (B) components thereto is 1 to 40 mass%, and a content ratio of the (C) components thereto is 10 to 49 mass%.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electrophotographic member, a transfer member, and an electrophotographic image forming apparatus.

In an electrophotographic image forming apparatus, some electrophotographic members used as transfer members and charging members have a conductive elastic layer.
Patent document 1 is disclosing the subject of the external resistance dependence of the electrical resistance of a conductive rubber roller provided with the rubber layer which has ion conductivity. And although the said subject can be solved by addition to the rubber layer of methacrylic acid ester, it describes that the said methacrylic acid ester bleeds from a base rubber, and introduces the new subject that a photosensitive body periphery is contaminated. ing. And about this new subject, patent document 1 can reduce the environmental dependence of the electrical resistance of an ion conductive rubber layer, even if the (meth) acrylic acid ester compound which has a specific structure reduces a content rate, As a result, it is disclosed that bleeding can also be suppressed.

JP 2014-51574 A

However, according to the study by the present inventors, the conductive roller according to Patent Document 1 has a (meth) acrylic ester ester when a current is continuously applied to the rubber layer under various circumstances. In some cases, the effect of suppressing bleeding is not always sufficient.
Therefore, the present inventors have proposed a new solution that does not depend on an additive such as (meth) acrylic acid ester, in order to reduce the environmental dependency of the electrical resistance of the rubber layer having ionic conductivity. Recognized that it was necessary to develop.

One embodiment of the present invention is directed to providing an electrophotographic member including an elastic layer having ionic conductivity, in which electrical resistance is less dependent on the environment, and the electrical resistance is less likely to change even after long-term use. Is.
Another aspect of the present invention is directed to providing an electrophotographic image forming apparatus capable of forming a high-quality electrophotographic image over a long period of time even in various environments.

According to one aspect of the present invention, there is provided an electrophotographic member comprising a substrate and a conductive elastic layer on the substrate,
The elastic layer contains a sulfur vulcanizate of a rubber mixture containing the following components (A) to (C):
(A) Acrylonitrile-butadiene rubber (NBR)
(B) Epichlorohydrin-allyl glycidyl ether (GCO)
(C) epichlorohydrin-ethylene oxide-allyl glycidyl ether (GECO),
The sulfur vulcanizate is
A matrix containing a structure derived from acrylonitrile as the component (A);
A domain including a structure derived from the epichlorohydrin of the component (B) and the component (C),
The content ratio of the component (A) with respect to the total content of the components (A) to (C) in the rubber mixture is 50 to 80% by mass, and the content ratio of the component (B) is 1 to An electrophotographic member having 40% by mass and a content ratio of the component (C) of 10 to 49% by mass is provided.

According to another aspect of the present invention, there is provided a transfer member that is the electrophotographic member.
According to yet another aspect of the present invention, there is provided an electrophotographic photosensitive member, and a transfer member disposed in contact with the electrophotographic photosensitive member, wherein the transfer member is the electrophotographic member. A photographic image forming apparatus is provided.

  According to one embodiment of the present invention, it is possible to obtain an electrophotographic member including an elastic layer having ionic conductivity, in which the electrical resistance is less dependent on the environment, and the electrical resistance does not easily change even after long-term use. . According to another aspect of the present invention, an electrophotographic image forming apparatus capable of forming a high-quality electrophotographic image over a long period of time can be obtained even under various environments.

It is the schematic of the member for electrophotography which concerns on 1 aspect of this invention. It is an example of an apparatus that can be used for forming a rubber tube (foamed elastic layer) composed of an extruder, a microwave vulcanizing apparatus, a hot air vulcanizing apparatus, a take-up machine, and a regular cutting machine. It is a conceptual diagram of the matrix domain structure in which the domain which concerns on 1 aspect of this invention has a core shell structure. It is the schematic which shows the jig which contacts the member for electrophotography, and a photoreceptor. 1 is a schematic configuration diagram of an electrophotographic image forming apparatus according to an aspect of the present invention.

  Hereinafter, the electrophotographic member according to one embodiment of the present invention will be described using a roller-shaped electrophotographic member (hereinafter, also simply referred to as “electrophotographic roller”) as an example.

  FIG. 1 shows an example of an electrophotographic roller according to one embodiment of the present invention, which includes a cylindrical or columnar substrate 11 and a conductive elastic layer (conductive elastic layer) 12 on the substrate.

[Substrate 11]
The base 11 supports a conductive elastic layer 12 formed on the base 11. The substrate 11 is not particularly limited as long as it has conductivity to conduct to the conductive elastic layer 12, but is preferably made of a metal such as aluminum, aluminum alloy, stainless steel, or iron. 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 11 may be any one selected from a hollow shape and a solid shape. The outer diameter of the substrate 11 can be appropriately selected according to the electrophotographic image forming apparatus to be mounted, and examples thereof include 4 mm or more and 10 mm or less. The outer diameter of the elastic layer can be appropriately selected according to the electrophotographic image forming apparatus to be mounted, and examples thereof include 7 mm or more and 20 mm or less.

[Elastic layer]
The elastic layer
(A) acrylonitrile-butadiene rubber (hereinafter sometimes referred to as “NBR”);
(B) an epichlorohydrin-allyl glycidyl ether binary copolymer (hereinafter sometimes referred to as “GCO”);
(C) a sulfur vulcanizate of a rubber mixture containing epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (hereinafter sometimes referred to as “GECO”).

The rubber mixture has a content ratio of the component (A) of 50 to 80% by mass and a content ratio of the component (B) of 1 with respect to the total content of the components (A) to (C). The content ratio of the component (C) is 10 to 49% by mass.
The sulfur vulcanizate of the rubber mixture having such a composition is
(A) a matrix containing a structure derived from acrylonitrile in the NBR component;
The present inventors have confirmed that it has a matrix domain structure having a domain containing a structure derived from epichlorohydrin of (B) component GCO and (C) component GECO.
And even if the electrophotographic member provided with such an elastic layer does not use the (meth) acrylic acid ester compound described in Patent Document 1, the environmental variability of the electrical resistance value is reduced. In addition, even when used for a long period of time, the fluctuation of the electric resistance value is small, and further, the environmental fluctuation of the electric resistance is small even after long-term use.

The present inventors presume the reason why the electrophotographic member according to this embodiment has such an effect as follows.
That is, as described above, the present inventors have found that the sulfur vulcanizate according to this embodiment includes a matrix containing a structure derived from the NBR component (A), the GCO of the component (B), and the GECO of the component (C). It has been confirmed that it has a matrix domain structure having a domain containing a structure derived from epichlorohydrin. From this observation result, in the sulfur vulcanizate according to this embodiment, as shown in FIG. 3, the domain 31 including the structure derived from GCO and GECO exists in the matrix 31 including the structure derived from NBR. It is thought that there is. And it is thought that the domain 32 is comprised with the core 32-1 containing the structure derived from GECO, and the shell 32-2 containing the structure derived from GCO which coat | covers the core 32-1.

  The reason for adopting such a structure is presumed to be due to the magnitude relationship between the SP values of NBR, GCO, and GECO, and the quantitative relationship of these three components in the rubber mixture. That is, the SP value of GECO and the SP value of NBR are farther from the SP value of GCO and the SP value of NBR. Therefore, in the process of sulfur vulcanization of the rubber mixture containing NBR, GCO, and GECO, NBR that occupies the majority of the rubber component in the rubber mixture forms a matrix. The GECO having the SP value of NBR and the SP value that is relatively farthest is phase-separated in a domain shape. Further, the GCO having an SP value of NBR that is relatively close to that of the NBR is arranged at the interface between the domain GECO and the matrix containing the NBR. As a result, after sulfur vulcanization, in the matrix 31 having the NBR-derived structure, the core 32-1 having the GECO-derived structure and the shell 32-2 including the GCO-derived structure around the core. It is considered that the domain 32 having the core-shell structure is formed.

In the sulfur vulcanizate considered to have such a matrix-domain structure, the domain core 32-1 includes a GECO-derived structure having an ethylene oxide unit that greatly contributes to a reduction in electrical resistance. Therefore, it is considered that the ionic conductivity of the sulfur vulcanizate is improved and a reduction in electric resistance is achieved.
On the other hand, since the domain shell 32-2 includes a GCO-derived structure having excellent ozone resistance, the ethylene of the core 32-1 when a current is passed through the elastic layer containing the sulfur vulcanizate for a long period of time. It is considered that chemical deterioration of the oxide unit is suppressed.
Moreover, it is thought that the shell 32-2 including the structure derived from GCO has high gas barrier properties and suppresses moisture in the external environment from reaching the core 32-1. As a result, the ethylene oxide unit of the core 32-1 that greatly contributes to the expression of ionic conductivity is less likely to be affected by external humidity, and it is considered that the environmental fluctuation of electrical resistance is significantly suppressed.

Further, the vulcanized product of the rubber mixture may contain impurities such as a vulcanized residue. Among impurities, polar substances that easily adhere to the photoreceptor gather in the domain due to their high affinity with the highly polar GCO and GECO in the conductive elastic layer. On the other hand, NBR constituting the matrix has more crosslinking points than GCO and GECO. Therefore, in the sulfur vulcanizate, the matrix portion has a dense cross-linked structure. Therefore, it is considered that the impurity component existing in the vicinity of the domain is difficult to move in the matrix.
For this reason, the electrophotographic member provided with the elastic layer according to this aspect is not easily bleeded even when used for a long time, and the other member such as an electrophotographic photosensitive member is in contact with the electrophotographic member. It is thought that the contamination of can be effectively suppressed.

[Rubber mixture]
[Rubber component (components (A) to (C))]
The conductive elastic layer 12 includes (A) acrylonitrile-butadiene rubber (NBR), (B) epichlorohydrin-allyl glycidyl ether (GCO), and (C) epichlorohydrin-ethylene oxide-allyl glycidyl ether (GECO). Contains sulfur vulcanizate of rubber mixture.
Here, the content ratio of the component (A) with respect to the total content of the components (A) to (C) in the rubber mixture is 50 to 80% by mass, and the content ratio of the component (B) is 1 to 40 masses. %, The content ratio of the component (C) is 10 to 49% by mass. More preferably, the content ratio of the component (A) is 50 to 60 mass%, the content ratio of the component (B) is 10 to 20 mass%, and the content ratio of the component (C) is 30 to 40 mass%. It is.

  The content ratio of NBR is 50 to 80% by mass with respect to the total content of NBR, GCO, and GECO. When the content ratio of NBR is less than 50% by mass, NBR does not have a matrix structure. On the other hand, when the content ratio of NBR exceeds 80% by mass, the ratio of GCO and GECO contributing to ionic conductivity is relatively reduced, so that the conductivity necessary for an electrophotographic member cannot be sufficiently obtained. In that case, in order to allow a desired current value to flow in the conductive layer, it is necessary to apply a higher voltage. As a result, when used over a long period of time, destruction of the NBR-derived structure is promoted, and the elastic layer May cause a decrease in strength.

  Also, by making the GCO content ratio 1-40 mass% and the GECO content ratio 10-49 mass% with respect to the total content of NBR, GCO, and GECO, the fluctuation of the electrical resistance value can be prolonged. In addition, the environmental variability of the electrical resistance value can be reduced over a long period of time. This is considered because the matrix domain structure described above can be formed.

  When the content ratio of GCO is less than 1% by mass and when the content ratio of GECO exceeds 49% by mass, the amount of GCO is too small relative to the amount of GECO, so that the wall of domain shell 32-2 It is considered that the thickness of the core 32-1 cannot be sufficiently covered, and the protection function of the ethylene oxide unit of the core 32-1 cannot be sufficiently obtained.

  In addition, when the content ratio of GCO exceeds 40% by mass, and when the content ratio of GECO is less than 10% by mass, the amount of GCO is excessively large relative to the amount of GECO, and the wall of the shell becomes too thick. Therefore, there may be a case where the excellent ion conductivity effect of the ethylene oxide unit in the core 32-1 cannot be fully enjoyed.

  In addition, the electrical resistance value of the conductive elastic layer 12 depends on the amount of ethylene oxide in the component (C) in the conductive elastic layer 12 in the range of the content ratio of the components (A) to (C). Fluctuate. In order to obtain a necessary electrical resistance value as the conductive elastic layer 12, the amount of ethylene oxide in the component (C) is 5 to 17% by mass with respect to the sum of the components (A) to (C) in the rubber mixture. It is more preferable that When used as a transfer member, the electrical resistance can be sufficiently reduced when the amount of ethylene oxide is 5% by mass or more. Moreover, the change with respect to the environmental fluctuation | variation of ion conductivity can be relieve | moderated more with the effect | action of a shell because the amount of ethylene oxide is 17 mass% or less.

  Moreover, it is more preferable that the content ratio of acrylonitrile in NBR is 15 to 26% by mass. Acrylonitrile is electrically conductive and also affects the mobility of the polymer molecular chains. When used as a transfer member, if the content ratio of acrylonitrile is 15% by mass or more, the resistance becomes sufficiently low, and better transferability can be obtained. Further, when the content is 26% by mass or less, the content of butadiene is not excessively short, and the degree of crosslinking due to vulcanization can be further suppressed. Therefore, since the compression set tends to be smaller, image defects are less likely to occur.

  Moreover, it is preferable that both GCO and GECO contain 4 mol% or more of allyl glycidyl ether units. The allyl glycidyl ether unit is a site for sulfur crosslinking and affects the degree of crosslinking. When the number of allyl glycidyl ether units is small, the degree of cross-linking of GCO and GECO is lowered accordingly. When both GCO and GECO contain 4 mol% or more of allyl glycidyl ether units, the degree of crosslinking becomes sufficiently high, the movement of the polymer molecular chain is suppressed, and the effect of suppressing impurity bleed can be further enhanced.

  The rubber mixture further includes sulfur for sulfur vulcanization. The sulfur content can be appropriately determined according to the degree of crosslinking and the like, and is not particularly limited. However, as a guideline, for example, it is preferably 1.0 to 4.0% by mass with respect to the rubber mixture. .

  In addition, although the electroconductive elastic layer 12 contains the sulfur vulcanizate of the rubber mixture containing (A)-(C) component, in the rubber mixture used for formation of the electroconductive elastic layer 12, as needed. A rubber component other than the components (A) to (C), a vulcanization aid, a foaming agent, a vulcanization accelerator, and other additives may be included. However, the content ratio of the components (A) to (C) in the rubber mixture is preferably 95% by mass or more and 98% by mass or more with respect to the total content of the rubber components in the rubber mixture. Is more preferable. Furthermore, it is particularly preferable that the rubber component in the rubber mixture consists only of the components (A) to (C) excluding impurities.

[Vulcanization aid]
The rubber mixture used for forming the conductive elastic layer 12 may contain a vulcanization aid. Examples of the vulcanization aid include zinc oxide, zinc stearate, stearic acid and the like.

[Foaming agent]
The rubber mixture used for forming the conductive elastic layer 12 may contain a foaming agent component. Examples of the foaming agent component include azodicarbonamide, sodium hydrogen carbonate, p, p′-oxybisbenzenesulfonyl hydrazide (OBSH), and the like.

[Vulcanization accelerator]
The rubber mixture used for forming the conductive elastic layer 12 may contain a vulcanization accelerator. Examples of the vulcanization accelerator include thiuram, thiazole, guanidine, sulfenamide, dithiocarbamate, and thiourea.

[Other additives]
In addition, carbon black, calcium carbonate, a conductive agent, and the like may be contained within a range that does not impede the functions of those contained in the rubber mixture used for forming the conductive elastic layer 12 described above.

In particular, regarding calcium carbonate, it is more preferable to contain 10 to 100% by mass of calcium carbonate having an average particle size of 2.5 μm or less with respect to the total content of the components (A) to (C).
Since calcium carbonate has a small relative dielectric constant with respect to the components (A) to (C), the dielectric constant of the conductive elastic layer 12 is reduced by containing calcium carbonate. When such a conductive elastic layer 12 is used as the conductive elastic layer of the transfer member, the transfer material P and the transfer member are transferred when the toner is transferred to the transfer material P such as paper due to the low dielectric constant. The shared voltage applied to the air gap can be reduced. In general, in an electrophotographic image forming apparatus, the voltage supplied to a transfer member is controlled according to the environment in order to maintain a current value necessary for toner transfer, and a high voltage is supplied in a low temperature and low humidity environment. A low voltage is supplied in a high humidity environment. Even in a very low-temperature and low-humidity environment (for example, temperature 10 ° C., humidity 7%) that requires a high voltage, the transfer material P and the transfer material P can be obtained by using a transfer member having a conductive elastic layer with a controlled relative dielectric constant. Occurrence of unnecessary discharge of the air gap between the transfer members can be suppressed, and better image reproducibility can be obtained.

  When the average particle diameter of calcium carbonate is 2.5 μm or less, image defects such as spots caused by the surface shape of the elastic layer can be sufficiently suppressed, and better image reproducibility can be obtained. Further, if the content ratio of calcium carbonate is 10% by mass or more with respect to the total content of the components (A) to (C), the relative dielectric constant becomes sufficiently low, and better image reproducibility is obtained. When it is 100% by mass or less, the rubber elasticity is not excessively insufficient, and better compression set can be maintained.

[Method for producing electrophotographic member]
An example of a method for producing an electrophotographic member according to one embodiment of the present invention will be described with reference to FIG. FIG. 2 shows an apparatus that can be used to form a rubber tube (foamed elastic layer) composed of a vent-type rubber extruder 21, a microwave vulcanizer 22, a hot-air vulcanizer 23, a take-up machine 24, and a regular cutting machine 25. It is an example.

  First, the rubber components (A) to (C), the vulcanization aid, and, if necessary, additives are further kneaded using a closed kneader such as a Banbury mixer or a kneader. Thereafter, using an open roll, a foaming agent, sulfur, 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 a vent type rubber extruder 21 to extrude a tubular product.

  Next, the obtained rubber tube is vulcanized and foamed. Vulcanization and foaming can be performed by a known method such as a microwave vulcanizer, a hot-air vulcanizer, an electric furnace, or a vulcanizer. It is preferable to use a vulcanizer including the microwave vulcanizer 22, vulcanize and foam using the microwave vulcanizer, and then further vulcanize and foam using the hot air vulcanizer 23. 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 conductive elastic layer in accordance with material characteristics.

  The vulcanized and foamed rubber tube is conveyed from the microwave vulcanizing device 22 and the hot air vulcanizing device 23 by the take-up machine 24 and cut to a desired size by the fixed length cutting machine 25. The rubber tube may be subjected to a cooling step before or after cutting.

  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 base is set to be larger than the length of the rubber tube, and a part of the base is exposed from both ends of the rubber tube as shown in FIG. The rubber tube into which the substrate is press-fitted is polished by a polishing machine to produce an electrophotographic member having a conductive elastic layer on the outer periphery of the substrate.

[Electrophotographic image forming apparatus]
An electrophotographic image forming apparatus according to one aspect of the present invention is disposed in contact with an electrophotographic photosensitive member, a transfer member disposed in contact with the electrophotographic photosensitive member, and the electrophotographic photosensitive member. A charging member; and a developing member disposed in contact with the electrophotographic photosensitive member. The electrophotographic member according to one embodiment of the present invention can be used for a member required to have a conductive elastic layer, for example, a transfer member, a charging member, and a developing member.
Here, an example of an electrophotographic image forming apparatus to which the above-described electrophotographic member is applied as a transfer member will be described in detail below.

FIG. 5 is a schematic configuration diagram of an electrophotographic image forming apparatus according to an aspect of the present invention.
In FIG. 5, reference numeral 1 denotes a cylindrical electrophotographic photosensitive member, which is driven to rotate at a predetermined peripheral speed in the direction of an arrow (clockwise direction) about an axis 2. The surface of the electrophotographic photosensitive member 1 that is driven to rotate is uniformly charged to a predetermined positive or negative potential by a charging member 3 such as a charging roller during the rotation process. Next, the surface of the charged electrophotographic photosensitive member 1 is intensity-modulated in response to a time-series electric digital image signal of target image information output from an exposure means (not shown) such as slit exposure or laser beam scanning exposure. The exposed exposure light 4 is received. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photoreceptor 1 is developed by regular development or reversal development with toner contained in the developer of the developing member 5 to form a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photosensitive member 1 is sequentially transferred onto a transfer material P such as paper by a transfer bias from the transfer member 6 which is a transfer member having the above-described electrophotographic member. To go. The transfer material P is taken out from a transfer material supply member (not shown) in synchronization with the rotation of the electrophotographic photosensitive member 1 and fed between the electrophotographic photosensitive member 1 and the transfer member 6 (contact portion). Is done. The transfer member 6 is applied with a bias voltage having a polarity opposite to the charge held by the toner from a bias power source (not shown).

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and is carried into the fixing member 8 to undergo a fixing process of the toner image. It is conveyed to.

  The surface of the electrophotographic photoreceptor 1 after the transfer of the toner image is cleaned by receiving a transfer residual developer (transfer residual toner) by a cleaning member 7 such as a cleaning blade. It is also possible to apply a cleanerless system that removes the transfer residual toner directly with a developing device or the like.

  Next, after being subjected to charge removal processing by pre-exposure light (not shown) from pre-exposure means (not shown), it is repeatedly used for image formation. As shown in FIG. 5, when the charging member 3 is a contact charging member using a charging roller or the like, pre-exposure is not necessarily required.

  A plurality of components including at least the electrophotographic photosensitive member 1 are selected from the constituent elements such as the electrophotographic photosensitive member 1, the charging member 3, the developing member 5, and the cleaning member 7, and these are stored in a container. The cartridge may be integrally supported. The process cartridge may be configured to be detachable from an electrophotographic image forming apparatus main body such as a copying machine or a laser beam printer. In FIG. 5, the electrophotographic photosensitive member 1, the charging member 3, the developing member 5, and the cleaning member 7 are integrally supported to form a cartridge, and a guide member 10 such as a rail of the electrophotographic image forming apparatus main body is used. The process cartridge 9 is detachable from the main body of the electrophotographic image forming apparatus. The electrophotographic image forming apparatus shown in FIG. 5 includes the cleaning member 7 and the fixing member 8, but these are not necessarily provided.

  For example, when the electrophotographic image forming apparatus is a copying machine or a printer, the exposure light 4 is reflected light or transmitted light from a document. Alternatively, the exposure light 4 is light emitted by reading a document with a sensor, converting it into a signal, scanning with a laser beam performed according to this signal, driving an LED array, driving a liquid crystal shutter array, or the like.

  Next, the present invention will be described in more detail by way of an example of an electrophotographic member that is a transfer member as an example of an electrophotographic member, but the present invention is not limited thereto.

First, materials listed in Table 1 were prepared as the components (A) to (C).

Moreover, the material of Table 2 was prepared as a vulcanization adjuvant, a filler, a vulcanizing agent, a foaming agent, and a vulcanization accelerator.

<Example 1>
1. Preparation of rubber mixture In accordance with the following rubber mixture material formulation (1), materials were added and mixed.

(Rubber mixture material formulation (1))
Acrylonitrile-butadiene rubber (A-1) 50 parts by mass Epichlorohydrin-allyl glycidyl ether binary copolymer (B-1) 15 parts by mass Epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer (C-1) ) 35 parts by mass / Filler No. 1 30 parts by mass / vulcanization aid No. 1 1 3.0 parts by mass / vulcanization aid No. 1 2 1.0 parts by weight

  The obtained mixture was put into a 7 L capacity closed kneader (device name: WDS7-30, manufactured by Nippon Spindle Manufacturing Co., Ltd.) and kneaded at a rotor rotation speed of 30 rpm for 7 minutes to obtain a kneaded product. At this time, the amount of ethylene oxide was 13.0% by mass with respect to the total mass of NBR, GCO, and GECO.

Materials were added to the kneaded product according to the following rubber mixture material formulation (2).
(Rubber mixture material formula (2))
-Foaming agent No. 1 2.5 parts by mass / Vulcanization accelerator No. 1 1 1.5 parts by mass / Vulcanization accelerator No. 1 2 2.0 parts by mass. 1 3.0 parts by mass

  The obtained rubber mixture is put into an open roll (device name: 12-inch open roll, manufactured by Kansai Roll Co., Ltd.) and kneaded for 15 minutes while cooling so that the temperature of the rubber mixture is maintained at 80 ° C. or lower.・ Dispersed. Finally, the shape of the rubber mixture was adjusted to a ribbon shape to prepare a rubber mixture for the conductive elastic layer.

2. Production of Electrophotographic Member A rubber tube to be a conductive elastic layer was produced using the production apparatus shown in FIG. First, the ribbon-like rubber mixture was supplied to a vent-type rubber extruder 21 (device name: 60 mm uniaxial bent rubber extruder, manufactured by Mitsuba Corporation) and extruded into a tube shape. Next, a vulcanizer (device name: 3.0 kW microwave continuous rubber vulcanization) including a microwave vulcanizer 22 (device name: special 3 kW microwave vulcanizer, manufactured by Microelectronics, maximum output 3.0 kW) The tube-like material was vulcanized and foamed by a line, manufactured by Micro Electronics Co., Ltd. to produce a rubber tube. In the microwave vulcanizer, the frequency was 2450 ± 50 MHz, the output was 1.2 kW, and the furnace temperature was set to 200 ° C. After vulcanization and foaming in a microwave vulcanizer, vulcanization and foaming were further performed in a hot air vulcanizer 23 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. Inside the microwave vulcanizer and hot air vulcanizer, the rubber tube was taken up by the take-up machine 24 and conveyed at a speed of 2.4 m / min. After vulcanization and foaming, the rubber tube surface temperature was cooled to 100 ° C. or lower with cold air, and then the rubber tube was cut into a length of 230 mm by a regular cutting machine 25.
Next, a stainless steel base (shaft core) 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 roller having a rubber length of 216 mm. An electrophotographic member having a conductive elastic layer on the outer periphery of a substrate, the outer peripheral surface of the roller being polished so that the outer diameter is 12.5 mm at a rotational speed of a polishing grindstone of 1800 rpm and a feed speed of 800 mm / min. Produced.

3. Confirmation of matrix domain structure A 3 mm square sample is cut out from the electroconductive elastic layer of the electrophotographic member, and the cut surface is SEM (trade name: Ultraplus, manufactured by Carl Zeiss) with an acceleration voltage of 1 kV and a magnification of 5000 times. The presence or absence of the matrix domain structure was judged from the backscattered electron image observed in the above.
Moreover, whether the domain has a structure derived from epichlorohydrin was determined by the following method. That is, the sample is observed at an acceleration voltage of 6 kV, a magnification of 5000 times, and a working distance of 8 mm using an energy dispersive X-ray analyzer (trade name: Noran System 7, manufactured by Thermo Fisher Scientific). And it was judged by confirming whether the chlorine atom which is contained in epichlorohydrin and not contained in NBR exists in a domain. That is, it was judged that the domain has a structure derived from epichlorohydrin because of the presence of a chlorine atom in the domain.

4). Measurement of electric resistance value 4-1. Calculation of electrical resistance value 1;
Table 3 shows the environmental conditions when measuring the electrical resistance value of the electrophotographic member and leaving it to stand.
First, after leaving the electrophotographic member in the environment 1 for 24 hours, the current value was measured by the following method in the same environment.
The electrophotographic member was pressed against a stainless steel drum having an outer diameter of 30 mm, and a load of 500 g was applied to each end of the base of the electrophotographic member. In this state, the stainless steel drum was rotated at a speed of 30 rpm / min, and a voltage of 1000 V was applied between the base of the electrophotographic member and the stainless steel drum while the electrophotographic member was driven to rotate. The current value flowing at that time was measured. From the measured current value, an electric resistance value (LogR converted value) was calculated according to Ohm's law, and the electric resistance value of the electrophotographic member was taken as 1.

4-2. Calculation of electrical resistance value 2;
The electrophotographic member whose electrical resistance value 1 was measured was allowed to stand in “Environment 2” for 48 hours, and under that environment, the current value was measured by the method described in “4. Measurement of electrical resistance value” above. The electrical resistance value 2 of the electrophotographic member was calculated.

4-3. Calculation of electrical resistance value 3;
The electrophotographic member whose electrical resistance value 2 was measured was left in “Environment 1” for 24 hours. Thereafter, the energization process and the leaving process were alternately repeated, the energization process was performed a total of 4 times, and the leaving process was performed a total of 3 times, and a current was passed through the electrophotographic member for a total of 24 hours.

(Energization process)
The electrophotographic member was pressed against a stainless steel drum having an outer diameter of 30 mm in “Environment 3”, and a load of 500 g was applied to both ends of the base of the electrophotographic member. In this state, while rotating the stainless steel drum at a speed of 10 rpm / min and rotating the electrophotographic member in a driven manner, a current of 120 μA flows between the base of the electrophotographic member and the stainless steel drum for 6 hours. did.
(Leave process)
The electrophotographic member was left in “Environment 1” for 15 hours while being separated from the stainless steel drum.

The electrophotographic member that had undergone the energization step and the leaving step was left in “Environment 2” for 48 hours. Thereafter, under the same environment, the current value was measured by the method described in “4. Measurement of electric resistance value”, and the electric resistance value 3 of the electrophotographic member was calculated.
When the difference between the electric resistance values before and after energization for a total of 24 hours (electric resistance value 3−electric resistance value 2) was less than 0.40, it was determined that the current carrying durability was excellent.

5. Calculation of electrical resistance value 4;
The electrophotographic member subjected to calculation of the electrical resistance value 3 was left in “Environment 4” for 48 hours. Thereafter, under the same environment, the current value was measured by the method described in “4. Measurement of electric resistance value”, and the electric resistance value 4 of the electrophotographic member was calculated. When the difference between the electric resistance values of the electrophotographic members in “Environment 2” and “Environment 4” (electric resistance value 3−electric resistance value 4) after energization for a total of 24 hours is less than 2.00, It was determined that the electrical resistance value was excellent in environmental variability.

6). Image evaluation 6-1. Evaluation of toner transferability
The electrophotographic member subjected to the calculation of the electric resistance value 4 was incorporated as a transfer roller of an electrophotographic laser printer (trade name: Laser Jet P1606dn, manufactured by HP). Using this laser printer, a halftone image was printed in “Environment 2”. The obtained halftone image was visually observed, and the transferability of the toner was evaluated according to the following criteria.
Rank A: Transferability is good.
Rank B: Transferability is slightly inferior.
Rank C: Transferability is poor.

6-2. Evaluation of image reproducibility This evaluation shows the effect of addition of calcium carbonate, and was evaluated in Example 1 and Examples 17-19.
After the electrophotographic member similar to each of the examples 1 and 17 to 19 was subjected to calculation evaluation of the electric resistance value 1, an electrophotographic laser printer (trade name: Laser Jet P1606dn, manufactured by HP) ) As a transfer member. Using this laser printer, vertical lines with a width of 0.2 mm were printed at intervals of 0.2 mm in an environment of a temperature of 10 ° C. and a humidity of 7%. The obtained image was visually observed, and the presence or absence of the vertical line resulting from the scattering of the toner in the horizontal direction and the degree thereof were evaluated according to the following criteria.
Rank A: Connection of vertical lines in the horizontal direction is not observed in the image.
Rank B: The connection of vertical lines in the horizontal direction is slightly observed in the image.
Even in the case of rank B, the image reproducibility has no problem during normal use.

7). Evaluation of Photocontamination Contamination and Compression Set of Electrophotographic Member 7-1. Evaluation Procedure Presence and Level of Contamination of Photoreceptor by Exuding Component from Electrophotographic Member, and Compression Permanent of Electrophotographic Member The presence or absence and the degree of distortion were evaluated as follows.
First, the photosensitive member was taken out from the toner cartridge for the laser printer (trade name: Laser Jet CE278A, manufactured by HP).

  Next, the electrophotographic member 42 and the photoreceptor 41 were brought into contact with each other using the jig shown in FIG. Specifically, the electrophotographic member that has not been subjected to the 24-hour energization process is pressed against the photoconductor with a spring pressure of 500 g on one side by a spring, and is allowed to stand still for 7 days in an environment of a temperature of 40 ° C. and a relative humidity of 95% RH. I put it.

  Next, the photoreceptor after standing was assembled in a toner cartridge. Moreover, the electrophotographic member after standing was attached to a laser printer as a transfer roller. The laser cartridge was loaded with the toner cartridge, and a halftone image was printed in “Environment 1”. By visually observing the obtained halftone image, the presence / absence of periodic streaks due to contamination on the photoconductor and the extent thereof, and the presence / absence of periodic streaks due to the compression set of the transfer roller Was evaluated according to the following criteria.

7-2. The presence and extent of periodic streaks due to contamination on the photoreceptor;
Rank A +: No streak of the photosensitive member period is observed in the image.
Rank A: Very few streaks of the photosensitive member period are observed in the image.
Rank B: Streaks of the photoreceptor period are observed in the image.
Rank C: Streaks of the photosensitive member period are remarkably observed in the image.

7-3. The presence and extent of periodic streaks due to compression set of the transfer roller;
Rank A: No streak of the transfer member period is observed in the image.
Rank B: A streak of the transfer member period is slightly observed in the image.
Rank C: A streak of the transfer member period is remarkably observed in the image.

8). Measurement of relative dielectric constant This evaluation shows the effect of addition of calcium carbonate, and was evaluated in Example 1 and Examples 17-19. The electrophotographic members similar to those in Examples 1 and 17 to 19 were subjected to calculation evaluation of the electric resistance value 1, and then the relative dielectric constant between the surface of the electrophotographic member and the cored bar was measured. First, impedance (Z) under the conditions of an AC voltage of 0.5 Vrms, a DC voltage of 1.0 V, and a frequency of 1000 Hz was measured using an impedance analyzer (trade name: Model 1260A, manufactured by Solartron). Using this impedance (Z), the relative dielectric constant of the roller was determined by calculating the capacitance component (C) as an RC parallel circuit.

9. Measurement and Evaluation Results Table 8 shows the measurement results and evaluation results of the electrophotographic members.
As a result, the change amount of the electrical resistance value (| electrical resistance value 3−electric resistance value 2 |) after passing through the energization process for 24 hours is 0.21, and the change amount of the electrical resistance value due to environmental fluctuation after long-term energization ( | Electric Resistance Value 3−Electric Resistance Value 4 |) was 1.62, and the fluctuation before and after long-term energization was small and good.
The matrix domain structure of the electroconductive elastic layer of the electrophotographic member contained the component (A) in the matrix. Further, as a result of image evaluation by the above-mentioned method using this electrophotographic member as a transfer member, the toner transferability is good, no streak in the photosensitive member cycle is observed, and the streak in the electrophotographic member cycle is also observed. Was not.

<Examples 2 to 19>
Electrophotographic members were obtained in the same manner as in Example 1 except that at least one of the type and amount of each material contained in the rubber mixture was changed to the conditions shown in Tables 4 to 6. The evaluation results are shown in Tables 8 to 10.

<Comparative Examples 1-8>
Electrophotographic members were obtained in the same manner as in Example 1 except that at least one of the type and amount of each material contained in the rubber mixture was changed to the conditions shown in Table 7. The evaluation results are shown in Table 11.
The electrophotographic member of Comparative Example 1 has an electric resistance value change amount of 0.46 due to long-term energization, and an electric resistance value change amount of 2.01 due to environmental fluctuation after long-term energization, which is durable and long-term energization. Both the subsequent environmental variability did not meet the target change in electrical resistance.
The electrophotographic member of Comparative Example 2 had an electric resistance value change amount of 0.70 due to long-term energization, and did not satisfy the target electric resistance value change amount in the energization durability.
The electrophotographic member of Comparative Example 3 has an electric resistance value change amount of 0.46 due to long-term energization and an electric resistance value change amount of 2.21 due to environmental fluctuations after long-term energization, which is durable and long-term energization. Both the subsequent environmental variability did not meet the target change in electrical resistance.
The electrophotographic member of Comparative Example 4 has an electric resistance value change amount of 0.44 due to long-term energization, and an electric resistance value change amount of 2.03 due to environmental fluctuation after long-term energization, which is durable and long-term energization. Both the subsequent environmental variability did not meet the target change in electrical resistance.
The electrophotographic member of Comparative Example 5 had an electric resistance value change amount of 0.65 due to long-term energization, and did not satisfy the target electric resistance value change amount in energization durability.
The electrophotographic member of Comparative Example 6 had an amount of change in electric resistance value of 0.63 due to long-term energization, and did not satisfy the target amount of change in electric resistance value in energization durability.
The electrophotographic member of Comparative Example 7 has an electric resistance value change amount of 0.43 due to long-term energization, and an electric resistance value change amount of 2.04 due to environmental fluctuation after long-term energization. Both the subsequent environmental variability did not meet the target change in electrical resistance.
In the electrophotographic member of Comparative Example 8, the amount of change in electrical resistance value due to environmental fluctuation after long-term energization is 2.08, and does not satisfy the target amount of change in electrical resistance value in environmental variability after long-term energization. It was.

  From the results of the examples, the electrophotographic member according to one aspect of the present invention achieves both suppression of high resistance due to long-term use (energization) and reduction of environmental variability of resistance that expands after long-term use. In addition, it was confirmed that the electrophotographic member has a small resistance variation even after long-term use and can suppress image defects.

11 Substrate 12 Conductive elastic layer 21 Vent type rubber extruder 22 Microwave vulcanizer (UHF)
23 Hot air vulcanizer (HAV)
24 Take-up machine 25 Standard cutting machine 31 Matrix 32 Domain 32-1 Core 32-2 Shell 41 Photoconductor 42 Electrophotographic member 43 Spring

Claims (7)

An electrophotographic member comprising a substrate and a conductive elastic layer on the substrate,
The elastic layer contains a sulfur vulcanizate of a rubber mixture containing the following components (A) to (C):
(A) Acrylonitrile-butadiene rubber (NBR)
(B) Epichlorohydrin-allyl glycidyl ether (GCO)
(C) epichlorohydrin-ethylene oxide-allyl glycidyl ether (GECO),
The sulfur vulcanizate is
A matrix containing a structure derived from acrylonitrile as the component (A);
A domain including a structure derived from the epichlorohydrin of the component (B) and the component (C),
The content ratio of the component (A) with respect to the total content of the components (A) to (C) in the rubber mixture is 50 to 80% by mass, and the content ratio of the component (B) is 1 to 40% by mass, and the content ratio of the component (C) is 10 to 49% by mass.   2. The electrophotographic image according to claim 1, wherein an amount of ethylene oxide in the component (C) is 5 to 17% by mass with respect to a total content of the components (A) to (C) in the rubber mixture. Materials.   The member for electrophotography according to claim 1, wherein both the component (B) and the component (C) contain 4 mol% or more of allyl glycidyl ether units.   The electrophotographic member according to any one of claims 1 to 3, wherein a content ratio of acrylonitrile in the component (A) is 15 to 26% by mass.   The said electroconductive elastic layer contains 10-100 mass% of calcium carbonate with an average particle diameter of 2.5 micrometers or less with respect to the sum total of content of said (A)-(C) component. The member for electrophotography of any one of these.   The electrophotographic member according to claim 1, wherein the electrophotographic member is a transfer member.   An electrophotographic image forming apparatus having an electrophotographic photosensitive member and a transfer member disposed in contact with the electrophotographic photosensitive member, wherein the transfer member is the electrophotographic member according to claim 6. An electrophotographic image forming apparatus.

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