JP2001082450A - Conductive roller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the formed state of an elastic body layer such as dimensional accuracy by dispersing grains formed of a cross-linked body of an ion conductive polymer, in a matrix formed of a cross linked body of an insulating polymer, to form the elastic layer body in a conductive roller provided with a shaft body and the elastic body layer. SOLUTION: This conductive roller such as a developing roller or charged roller used for an electrophotographic device such as a copying machine, has an elastic body layer 11 formed along the outer peripheral surface of a shaft body 10. The elastic body layer 11 is formed by dispersing grains 2 formed of a cross-linked body of an ion conductive polymer in a matrix formed of a cross-linked body 1 of an insulating polymer. The elastic body layer 11 is normally formed using a rubber composition containing the insulating polymer and its cross-linking agent, and the ion conductive polymer and its cross-linking agent. The insulating polymer exhibits insulating property with the electric resistance value of 1012 Ω.cm or more, and ethylene-propylene-diene rubber, isoprene rubber or butadiene rubber is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive roll such as a developing roll, a charging roll, a transfer roll, a neutralizing roll, and a fixing roll used in an electrophotographic apparatus such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art Conventionally, a conductive roll has a structure in which an elastic layer is formed on the outer peripheral surface of a shaft, an intermediate layer is formed on the outer peripheral surface, and a surface layer is formed on the outer peripheral surface. Is used. In the case where the elastic layer has ion conductivity, a rubber composition containing acrylonitrile-butadiene rubber (NBR) or epichlorohydrin-ethylene oxide rubber (ECO) as a main component and an ionic conductive agent or the like mixed therewith is used. That is common.

[0003]

However, since the rubber composition has a high polymer viscosity, it has a drawback that the moldability is poor and good dimensional accuracy cannot be obtained. In addition, the elastic layer using the rubber composition tends to have a variation in electric resistance value, and tends to cause problems such as uneven image density. Therefore, a conductive roll on which an elastic layer is formed using the above rubber composition is not suitable for a recent electrophotographic apparatus requiring high image quality.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a conductive roll which has a favorable state of formation of an elastic layer such as dimensional accuracy and exhibits uniform ionic conductivity. And

[0005]

In order to achieve the above object, a conductive roll of the present invention is a conductive roll having a shaft and an elastic layer formed on the outer peripheral surface of the shaft. The elastic layer has a structure in which a crosslinked body of an insulating polymer is used as a matrix, and particles composed of a crosslinked body of an ion conductive polymer are dispersed in the matrix.

That is, the inventors of the present invention have focused on the material for forming the elastic layer in order to obtain a conductive roll exhibiting uniform ion conductivity in which the state of formation of the elastic layer such as dimensional accuracy is good. I did my research. In the process, a polymer exhibiting ionic conductivity (ionic conductive polymer) and an ethylene-propylene-diene rubber (EP
It was conceived that by using a polymer having an insulating property (insulating polymer) such as DM), the electric resistance value was made uniform and the dimensional accuracy and the like were improved. However, since both polymers usually have poor compatibility, it was found that if both polymers were simultaneously cross-linked under normal conditions, the ionic conductive polymer was unevenly distributed, resulting in uneven electric resistance. Therefore, as a result of repeated studies, the ion-conductive polymer was cross-linked by so-called dynamic cross-linking to form particles, and if the insulating polymer serving as the matrix was cross-linked, particles of the cross-linked ion-conductive polymer could be obtained. It has been found that the particle size is uniform to some extent and the particles are uniformly dispersed. As a result, the electric resistance value of the elastic layer of the conductive roll can be made uniform and, at the same time, good dimensional accuracy and the like can be obtained. That is, the shaft body,
In a conductive roll provided with an elastic layer formed on the outer peripheral surface of the shaft, the elastic layer has a cross-linked body of an insulating polymer as a matrix, and a cross-linked body of an ion-conductive polymer in the matrix. It has been found that when the particles are dispersed, the dimensional accuracy and the like are good, the ionic conductivity is uniform, and an excellent image can be obtained, and the present invention has been achieved.

In particular, the particle size distribution characteristics (X) of the particles comprising the crosslinked ionic conductive polymer are 0.1 μm
When the cross-sectional areas of the above particles are measured and sequentially accumulated in ascending order, the particle size at the point where the cumulative cross-sectional area is 90% of the total cumulative cross-sectional area is 30 μm or less. It is suitable as the conductive roll of the present invention.

Further, the use of EPDM as the insulating polymer constituting the elastic layer of the conductive roll of the present invention and the use of ECO as the ionic conductive polymer make it easy to perform dynamic cross-linking and to adjust the electric resistance value. It is particularly preferable from the viewpoints of fabrication and dimensional accuracy.

Further, when the ionic conductive agent is contained in the elastic layer of the conductive roll of the present invention, the ionic conductive agent is appropriately dispersed in the matrix, and the elastic layer exhibits good ionic conductivity. Becomes The electric resistance value of the elastic layer of the conductive roll of the present invention is 1 × 10 ⁷ to 1 × 10 ^7.
If it is set in the range of ¹⁰ Ω · cm, it is suitable as a conductive roll for an electrophotographic apparatus. Further, the elastic layer of the conductive roll of the present invention is formed by using a rubber composition containing EPDM in a ratio of 10 to 70% by volume based on the whole, and the elastic layer has a variation in electric resistance of 0%. If the number is not more than 5 digits, it is particularly suitable as a conductive roll for an electrophotographic apparatus.

[0010]

Next, an embodiment of the present invention will be described.

The conductive roll of the present invention is formed by forming a special elastic layer 11 along the outer peripheral surface of a shaft 10 as shown in FIGS. 1 and 2, for example. The special elastic layer 11 has a structure in which a crosslinked body 1 of an insulating polymer is used as a matrix, and particles 2 made of a crosslinked body of an ion conductive polymer are dispersed in the matrix.

The shaft body 10 is not particularly limited. For example, a metal core made of a solid metal body, a metal cylindrical body whose inside is hollowed out, or the like is used. Examples of the material include stainless steel, aluminum, and iron plated. If necessary, an adhesive, a primer, or the like may be applied on the shaft 10, and the adhesive, the primer, or the like may be made conductive as necessary.

The special elastic layer 11 formed on the outer peripheral surface of the shaft 10 is usually made of a rubber composition containing an insulating polymer and a crosslinking agent thereof, and an ion-conductive polymer and a crosslinking agent thereof. It is formed using.

The insulating polymer has an electric resistance value of 10
^It has an insulation of ¹² Ω · cm or more.
PDM, isoprene rubber (IR), butadiene rubber (B
R) and the like. These may be used alone or in combination of two or more. Among them, EPDM is preferably used because moldability is particularly good. EP
The diene component of DM is not particularly limited, and for example, ethylidene norbornene (ENB), dichloropentadiene (DCPD), or the like can be used.

It is preferable that the insulating polymer is blended in a proportion of 10 to 70% by volume in the whole rubber composition. More preferably, it is in the range of 30 to 70% by volume. That is, if it is less than 10% by volume, there is a tendency that excellent effects derived from the insulating polymer such as moldability cannot be obtained, and if it exceeds 70% by volume, the compounding ratio of the ion conductive polymer becomes relatively small. This is because there is a possibility that the elastic layer 11 does not exhibit proper ionic conductivity. In particular, EPDM is used as an insulating polymer.
It is preferable that DM is blended in a proportion of 10 to 70% by volume in the whole rubber composition, because good moldability and uniform electric resistance can be realized.

As the cross-linking agent for cross-linking the insulating polymer, various conventionally known cross-linking agents can be used. When EPDM is used as the insulating polymer, the compression set of the elastic layer 11 is good. Because
It is preferable to use a peroxide crosslinking agent. The mixing ratio of the crosslinking agent is 1 to 15 with respect to 100 parts by weight of the insulating polymer (hereinafter abbreviated as “parts”) because the elastic layer 11 needs to maintain appropriate elasticity.
It is preferably set in the range of parts.

The ionic conductive polymer blended with the insulating polymer has an electric resistance of 10 ⁷ to 1.
It exhibits an ionic conductivity of ⁰⁹ Ω · cm, and examples thereof include epichlorohydrin rubber and epichlorohydrin-ethylene oxide rubber (ECO). These can be used alone or in combination of two or more. Among them, E is preferred because it exhibits good ionic conductivity.
CO is preferred.

Preferably, the ionic conductive polymer is blended at a ratio of 30 to 90% by volume in the whole rubber composition. More preferably, it is in the range of 50 to 80% by volume. That is, when the content is less than 30% by volume, the ion conductivity tends not to be sufficiently exhibited. On the other hand, when the content exceeds 90% by volume, the compounding ratio of the insulating polymer becomes relatively small, and a favorable elastic layer 11 is formed. This is because it may not be performed.

As the cross-linking agent for cross-linking the ionic conductive polymer, various conventionally known cross-linking agents can be used. Among them, thiourea is preferably used in consideration of easiness of dynamic cross-linking and the like. . The mixing ratio of the cross-linking agent is preferably set in the range of 1 to 8 parts with respect to 100 parts of the ion-conductive polymer, since it is necessary to maintain appropriate elasticity of the elastic layer 11. .

The rubber composition used to form the elastic layer 11 of the conductive roll according to the present invention includes, in addition to the insulating polymer and its crosslinking agent, the ion-conductive polymer and its crosslinking agent, An agent can be compounded.

Examples of the ionic conductive agent include borates, lithium salts, quaternary ammonium salts and the like.
These may be used alone or in combination of two or more.

Further, in addition to the above, the rubber composition further comprises:
A plasticizer, an oil, a crosslinking accelerator, a crosslinking retarder, an antioxidant, a coloring agent, and the like may be appropriately blended.

The conductive roll of the present invention is manufactured, for example, as follows. That is, first, the ion-conductive polymer, the insulating polymer, and other additives except the crosslinking agent are kneaded using a kneader such as a Banbury mixer, and then a crosslinking agent for the ion-conductive polymer is added,
By heating, only the ion conductive polymer is crosslinked. This is a cross-linking step called so-called dynamic cross-linking, in which a cross-linked body of the ion-conductive polymer is formed into particles, and a rubber composition is obtained in which the particles are dispersed in an uncross-linked insulating polymer. When a plurality of polymers are used as the ion-conductive polymer, the operation of the dynamic crosslinking is performed a plurality of times (when the crosslinking system is the same, simultaneously).

The Mooney viscosity (121 ° C., MLV _{1 + 3} ) of the rubber composition obtained by dynamically cross-linking the ionic conductive polymer (without adding a cross-linking agent to the insulating polymer) may be less than 28. Preferably, it is in the range of 8-18. That is, if it exceeds 28, the viscosity is too high, which may cause molding failure and the like.

Next, a crosslinking agent for an insulating polymer is added to a rubber composition obtained by dispersing the particles 2 comprising a crosslinked product of the ion conductive polymer in an uncrosslinked insulating polymer. The rubber composition comprising
0 is filled in the injection mold set at a predetermined position, and the insulating polymer is crosslinked by heating. Thereafter, the mold is removed, and a conductive roll on which the elastic layer 11 is formed along the outer peripheral surface of the shaft body 10 is manufactured.

The method of forming the elastic layer 11 is not limited to the injection molding method, but may be formed by a casting method or a method of polishing after press molding.

As shown in FIG. 2, the elastic layer 11 of the conductive roll thus obtained has a crosslinked body 1 of an insulating polymer as a matrix, and a crosslinked body of an ionic conductive polymer in the matrix. Since the particles 2 are dispersed, the particles exhibit uniform ionic conductivity. For example, when EPDM is used in a proportion of 10 to 70% by volume in the whole rubber composition, variation in the electric resistance value of the elastic layer 11 can be suppressed to 0.5 digit or less. In addition, an effect derived from an insulating polymer having good moldability and the like is obtained, and the state of formation of the elastic layer 11 is improved.

It is preferable that the particles 2 made of the crosslinked ionic conductive polymer satisfy the following particle size distribution characteristics (X). When this property (X) is satisfied, the elastic layer 1 particularly exhibits uniform ion conductivity.
1, and good moldability and surface roughness are maintained.

(X) When the cross-sectional areas of the particles having a particle diameter of 0.1 μm or more are measured and these are sequentially accumulated from the smallest one,
The particle size at the point where the cumulative sectional area is 90% of the total cumulative sectional area is 30 μm or less.

Here, “when the cross-sectional areas of particles having a particle size of 0.1 μm or more are measured and the values are sequentially accumulated in ascending order” in the particle size distribution characteristics (X) is as follows. Say. That is, first, the particles 2 composed of a crosslinked body of the ion conductive polymer distributed in the elastic layer 11
Among them, the cross-sectional area of particles having a particle diameter of 0.1 μm or more is measured.
The particle size refers to the maximum particle size of the particles. For example, when the cross-sectional shape of a particle is circular, the diameter is the particle size, and when the cross-sectional shape of the particle is an ellipse, the long diameter is the particle size. The measurement can be performed, for example, by observing the cross section of the elastic layer 11 with a scanning electron microscope. This observation does not need to be performed for the entire elastic layer 11 and may be partially performed by arbitrarily determining an observation position (sampling position). The number of sampling points is preferably 4 to 30, particularly preferably 20 to 30. The calculation of the cross-sectional area is performed according to the cross-sectional shape of the particles. . Then, the cross-sectional areas are sequentially accumulated in ascending order, and the total accumulated cross-sectional area is calculated.

In the particle size distribution characteristics described above, "the particle size at the point where the cumulative sectional area is 90% of the total cumulative sectional area is 30 μm or less" means the following. That is, first, 90% of the total cumulative sectional area
The cumulative cross-sectional area of the ratio is derived. The particle size at the point where the cumulative cross-sectional area is 90% (hereinafter referred to as “90%
Cumulative dispersed particle size ”). An example of this is shown in the graph of FIG. In this graph, the vertical axis indicates the cumulative cross-sectional area ratio (%), and the horizontal axis indicates the particle diameter (μm) and the particle cross-sectional area (μm ² ). As shown in the figure, when the particles are sequentially accumulated in ascending order of decreasing cross-sectional area, a curve is obtained in which the cumulative cross-sectional area ratio increases as the particle size (cross-sectional area) increases. Then, as shown by the dotted line, the particle size at a point corresponding to the 90% cumulative sectional area is determined. If the particle size at this point is 30 μm or less, the particle size distribution characteristic (X) is satisfied. The particle size is 1 to
It is particularly preferred that it is in the range of 10 μm.

Then, the elastic layer 11 of the conductive roll
Is preferably adjusted within the range of 1 × 10 ⁷ to 1 × 10 ¹⁰ Ω · cm from the viewpoint of exhibiting appropriate ionic conductivity. The electric resistance value is JIS using an electrode of about 0.5 to ² mm ^2.
It is a value measured according to K 6911.

The conductive roll of the present invention can be used as a roll such as a developing roll, a charging roll, a transfer roll, a charge removing roll, and a fixing roll. In addition, as an example of the conductive roll of the present invention, a roll in which only the elastic layer 11 is formed on the outer peripheral surface of the shaft body has been described. However, the present invention is not necessarily limited to this. An appropriate number of layers may be formed on the outer periphery of the body layer 11. For example, when used as a developing roll, as shown in FIG.
An intermediate layer 12 and a surface layer 13 are further formed on the outer periphery of the elastic layer 11 formed along the outer periphery of the zero. In this case, the thickness of the elastic layer 11 is preferably set in the range of 0.5 to 10 mm, and particularly preferably 3 to 6 mm. The thickness of the intermediate layer 12 is usually set in the range of 1 to 90 μm, preferably 3 to 30 μm, and the thickness of the surface layer 13 is usually set in the range of 3 to 100 μm, preferably 5 to 50 μm. It is.

Next, examples will be described together with comparative examples.

[0035]

Example 1 First, 30 parts of EPDM (Nordel IP 5530 manufactured by Dupont Dow Elastomer Co.), 8 parts of its crosslinking agent (Perhexa 25B40 manufactured by NOF Corporation), and ECO (Epichromer CG105 manufactured by Daiso)
70 parts and its crosslinking agent (Suncellar 22 manufactured by Sanshin Chemical Co., Ltd.)
C) 0.5 part and 1.5 parts of an acid acceptor (Hydrotalcite DHT4A manufactured by Kyowa Chemical Co., Ltd.) are prepared, and all the raw materials except for the cross-linking agent of EPDM are put into a Banbury mixer and heated at 130 ° C. Kneaded for 15 minutes (dynamic crosslinking). At this time, the Mooney viscosity (121 ° C., MLV _{1 + 3} ) was 14.5. Thereafter, a cross-linking agent of EPDM is added and further kneaded, and then a core metal (diameter: 10 mm, SUS304) serving as a shaft is formed.
Was introduced into a mold for injection molding on which EPDM was set, and EPDM was heated and crosslinked. In this way, a conductive roll (base roll) in which the elastic layer was formed along the outer peripheral surface of the shaft was produced.

[0036]

Embodiment 2 EPDM (Nordel IP 5 manufactured by Dupont Dow Elastomer Co., Ltd.) was used as a material for forming the elastic layer.
530) 20 parts, 10 parts of liquid EPDM (TRILENE 66 manufactured by Uniroyal), 8 parts of a crosslinking agent thereof (Perhexa 25B40 manufactured by NOF Corporation), and 70 parts of ECO (Epichromer CG105 manufactured by Daiso), 0.5 parts of the crosslinking agent (Suncellar 22C manufactured by Sanshin Chemical Co., Ltd.)
Acid acceptor (Kyowa Chemical Co., Ltd. Hydrotalcite DHT4)
A) 1.5 parts were used. Otherwise, in the same manner as in Example 1, a conductive roll (base roll) was produced. The Mooney viscosity after dynamic crosslinking (121 ° C., ML
V _{1 + 3} ) was 8.9.

[0037]

Example 3 All the raw materials except the EPDM crosslinking agent were put into a Banbury mixer and kneaded at 130 ° C. for 5 minutes (dynamic crosslinking). Otherwise, in the same manner as in Example 1, a conductive roll (base roll) was manufactured. The Mooney viscosity (121 ° C., MLV _{1 + 3} ) after dynamic crosslinking is 1
5.5.

[0038]

Example 4 A conductive roll (base roll) was produced in the same manner as in Example 1, except that 0.67 parts of an ion conductive agent (LR147 manufactured by Nippon Carlit Co., Ltd.) was added as an elastic layer forming material. did. The Mooney viscosity (121 ° C., MLV _{1 + 3} ) after dynamic crosslinking was 14.2.

[0039]

Comparative Example 1 Example 3 except that no dynamic crosslinking was performed.
In the same manner as in the above, a conductive roll (base roll) was manufactured. That is, all the materials except the crosslinking agent for forming the elastic layer are put into a Banbury mixer and kneaded, then the crosslinking agent is charged and kneaded, and then the injection molding metal on which the core metal serving as the shaft is set is set. It was introduced into a mold, molded, and crosslinked by heating. Thereafter, the mold was removed to produce a conductive roll (base roll) in which an elastic layer was formed on the outer peripheral surface of the shaft body. The Mooney viscosity of the rubber composition after kneading (121 ° C., M
LV _{1 + 3} ) was 13.8.

[0040]

Comparative Example 2 100 parts of NBR (Nipol DN202 manufactured by Zeon Corporation) and liquid N
70 parts of BR (Nipol 1312 manufactured by Zeon Corporation)
1 part of stearic acid, 5 parts of zinc oxide, 30 parts of calcium carbonate, and an ion conductive agent (LR1 manufactured by Nippon Carlit Co., Ltd.)
47) 1 part and a crosslinking agent (Perhexa 25 manufactured by NOF Corporation)
B40), and a conductive roll (base roll) was produced in the same manner as in Comparative Example 1 using 8 parts. The Mooney viscosity (121 ° C., MLV 1 _{+ 3} ) of the rubber composition after kneading is as follows:
23.3.

[0041]

Comparative Example 3 100 parts of ECO (Epichromer CG105 manufactured by Daiso Co.) and an acid acceptor (hydrotalcite DHT4A manufactured by Kyowa Chemical Co., Ltd.) were used as materials for forming the elastic layer.
And 0.5 parts of stearic acid, 1 part of an ion conductive agent (LR147 manufactured by Nippon Carlit Co., Ltd.), and 2 parts of a cross-linking agent (Suncellar 22C manufactured by Sanshin Chemical Co., Ltd.). Thus, a conductive roll (base roll) was manufactured.
The Mooney viscosity of the kneaded rubber composition (121 ° C.,
MLV _{1 + 3} ) was 25.8.

[0042]

Comparative Example 4 EPDM (Nordel IP 5 manufactured by Dupont Dow Elastomer Co., Ltd.) was used as a material for forming the elastic layer.
565) 100 parts, 1 part of stearic acid, and zinc oxide 5
Parts, acetylene black (Denka Black) 40 parts, and process oil (Diana Process PW380) 9
A conductive roll (base roll) was produced in the same manner as in Comparative Example 1, using 0 parts, 3 parts of a co-crosslinking agent (TAIC), and 8 parts of a crosslinking agent (Perhexa 25B40). In addition,
Mooney viscosity of rubber composition after kneading (121 ° C., MLV
_{1 + 3} ) was 19.1.

With respect to the thus obtained conductive rolls of Examples and Comparative Examples, the 90% cumulative dispersed particle size,
The electrical resistance value, the variation of the electrical resistance value, the dimensional accuracy, and the compression set were measured and evaluated according to the following methods, and the results are shown in Tables 1 and 2 below.

[90% Cumulative Dispersion Particle Size] As shown in FIG. 5 (A), two cuts are made at right angles to the axial direction in the elastic layer portion of the conductive roll 20 to form a ring-shaped section. A cut was made in the direction and cut out of the cored bar to produce a sample 20a as shown in FIG. Then, as shown in the cross-sectional view of the sample 20a in the same figure (C), the scanning electron microscope (S-410
0, manufactured by Horiba Ltd.). Then, the 90% cumulative dispersed particle size was automatically obtained by using the image processor (Spica II, manufactured by Nippon Avionics) according to the procedure described above.

[Electrical Resistance Value, Variation in Electric Resistance Value] The electric resistance value (30 points) of the elastic layer of the conductive roll was calculated as follows:
It was measured according to JIS K 6911 using a 1 mm ² electrode. Then, the median value (the 15th from the smallest) was displayed, and the difference between the maximum value and the minimum value was displayed as a digit as a variation.

[Dimensional Accuracy] The elastic layer of the obtained conductive roll was evaluated by visual observation. In other words, there is no molding defect such as dent or swelling of 0.3 mm or more on the surface of the elastic layer, and the mold accuracy (straightness tolerance, roundness tolerance, cylindricity tolerance, runout tolerance) is within 2 times.の も の was given for those with dimensional accuracy, and x was given for those with poor molding or poor dimensional accuracy of the product.

[Compression Permanent Set] Measured according to JIS K 6301 under the conditions of a temperature of 70 ° C., a test time of 22 hours, and a compression ratio of 25%. If the measured value is 5% or less, it can be said that the compression set is good. Therefore, those with 5% or less were marked with "O", and those with more than 5% were marked with "X".

[0048]

[Table 1]

[0049]

[Table 2]

From the results shown in Tables 1 and 2, from Example 1
It can be seen that the products 4 to 4 had good dimensional accuracy and suppressed variation in electric resistance value. Further, it can be seen that the compression set is good. On the other hand, it can be seen that Comparative Examples 1 to 4 have large variations in the electric resistance value and defects in dimensional accuracy.

[0051]

Example 5 An intermediate layer and a surface layer were formed on the outer peripheral surface of a conductive roll (base roll) of Example 1. The formation of the intermediate layer and the surface layer was performed as follows.
That is, first, NBR (Nihon Zeon, Nipol DN
401) 100 parts and conductive agent (acetylene black) 3
0 parts, stearic acid 0.5 parts, ZnO (zinc white) 5
Parts, 1 part of the vulcanization accelerator BZ, 2 parts of the vulcanization accelerator CZ, and 3 parts of sulfur are kneaded, and then dispersed in an organic solvent to prepare an intermediate layer forming material (coating liquid). did. Next, this coating solution is applied by a roll coating method.
After coating on the outer peripheral surface of the base roll, drying and heat treatment were performed to form an intermediate layer on the outer peripheral surface of the base roll. After kneading 100 parts of a polyurethane elastomer (Nipporan 2304, manufactured by Nippon Polyurethane Industry Co., Ltd.), 20 parts of carbon black, and 25 parts of a curing agent (Bernock D-750, manufactured by Dainippon Ink and Chemicals, Inc.) Was dispersed in an organic solvent to prepare a surface layer forming material (coating liquid). Next, the coating liquid was applied to the outer peripheral surface of the intermediate layer by a roll coating method, and then dried and heated to form a surface layer on the outer peripheral surface of the intermediate layer. Thus, a conductive roll having a three-layer structure was manufactured.

[0052]

Example 6 A three-layered film was produced in the same manner as in Example 5, except that the conductive roll (base roll) of Example 2 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

[0053]

Example 7 A three-layered film was produced in the same manner as in Example 5 except that the conductive roll (base roll) of Example 3 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

[0054]

Example 8 The same procedure as in Example 5 was repeated, except that the conductive roll (base roll) of Example 4 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

[0055]

Comparative Example 5 Three layers were formed in the same manner as in Example 5 except that the conductive roll (base roll) of Comparative Example 1 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

[0056]

Comparative Example 6 Three layers were formed in the same manner as in Example 5, except that the conductive roll (base roll) of Comparative Example 2 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

[0057]

Comparative Example 7 Three layers were formed in the same manner as in Example 5 except that the conductive roll (base roll) of Comparative Example 3 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

[0058]

Comparative Example 8 Three layers were formed in the same manner as in Example 5 except that the conductive roll (base roll) of Comparative Example 4 was used instead of the conductive roll (base roll) of Example 1. A conductive roll having the structure was manufactured.

The conductive rolls of the example and comparative examples thus obtained were evaluated for the presence or absence of uneven image density by the following method, and the dimensional accuracy was evaluated by the above method. The results are shown in Tables 3 and 4 below.

[Image Density Unevenness] A halftone image was produced by incorporating a conductive roll as a developing roll into an electrophotographic copying machine. Then, the density is measured by a Macbeth densitometer, and if the difference between the maximum value and the minimum value is 0.1 or less, it can be said that there is no density unevenness.
The case where it exceeds 0.1 was indicated as x.

[0061]

[Table 3]

[0062]

[Table 4]

From the results in Tables 3 and 4, Comparative Example 5
In contrast, the products of Comparative Examples 6 and 7 have inferior dimensional accuracy, whereas the products of Examples 5 to 8 have no image density unevenness. It turns out that it is favorable.

[0064]

As described above, in the conductive roll of the present invention, the elastic layer formed on the outer peripheral surface of the shaft body has a cross-linked insulating polymer as a matrix, and the ion-conductive polymer is contained in the matrix. Are formed by dispersing particles comprising a crosslinked product of Therefore, particles exhibiting ion conductivity are uniformly dispersed in the elastic layer, and the entire elastic layer exhibits uniform ion conductivity. Moreover, since an insulating polymer such as EPDM having good moldability is used for the matrix, the state of formation of the elastic layer such as dimensional accuracy is good. Therefore, even when used in an electrophotographic apparatus or the like, a defect such as uneven image density does not occur, and an excellent image can be obtained.

In particular, EPDM is used as the insulating polymer.
When ECO is used as the ionic conductive polymer, the particles are formed in a good state by dynamic crosslinking, so that the ionic conductivity is uniform and the dimensional accuracy is good. An elastic layer is formed and is particularly suitable as a conductive roll for an electrophotographic apparatus.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing one example of an elastic layer of a conductive roll of the present invention.

FIG. 2 is a schematic enlarged view of the conductive roll of FIG.

FIG. 3 is a graph showing the relationship between the particle size of the particles and the cumulative cross-sectional area ratio of the particles.

FIG. 4 is a cross-sectional view schematically showing another example of the conductive roll of the present invention.

5A is a perspective view showing a state in which a cut is made in the conductive roll, FIG. 5B is a perspective view of a sample cut from the conductive roll, and FIG. 5C is a cross section of the sample. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crosslinked body of an insulating polymer 2 Particles composed of a crosslinked body of an ion conductive polymer 10 Shaft 11 Elastic layer

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/06 G03G 21/00 340 3J103 (72) Inventor Akihiko Kaji Odai, Komaki, Aichi Prefecture No. 3600 Tokai Rubber Industries Co., Ltd. (72) Inventor Kenichi Ohoe Komaki City, Aichi Pref. 2H077 AD06 FA11 FA21 FA25 3J103 AA02 AA13 AA15 AA21 AA51 BA41 FA14 FA18 GA02 GA52 GA57 GA58 GA60 GA64 GA66 GA74 HA03 HA04 HA05 HA12 HA20 HA33 HA37 HA41 HA48 HA53 HA54 HA55

Claims (6)

[Claims] 1. A conductive roll comprising a shaft and an elastic layer formed on the outer peripheral surface of the shaft, wherein the elastic layer has a crosslinked body of an insulating polymer as a matrix, A conductive roll, wherein particles comprising a crosslinked product of an ion conductive polymer are dispersed in a matrix. 2. The conductive roll according to claim 1, wherein the particles comprising the crosslinked product of the ion conductive polymer satisfy the following particle size distribution characteristics (X). (X) When the cross-sectional areas of particles having a particle diameter of 0.1 μm or more are measured and sequentially accumulated in ascending order, the particle diameter at a point where the cumulative cross-sectional area is 90% of the total cumulative cross-sectional area Is 30 μm or less. 3. The conductive roll according to claim 1, wherein the insulating polymer is ethylene-propylene-diene rubber, and the ionic conductive polymer is epichlorohydrin-ethylene oxide rubber. 4. The conductive roll according to claim 1, wherein an ion conductive agent is dispersed in the elastic layer. 5. The electric resistance value of the elastic layer is 1 × 10
The conductive roll according to claim 1, wherein the conductive roll is set in a range of ⁷ to 1 × 10 ¹⁰ Ω · cm. 6. The elastic layer is formed using a rubber composition containing ethylene-propylene-diene rubber in a ratio of 10 to 70% by volume based on the whole, and the elastic layer has a variation in electric resistance value. , Less than 0.5 digits
The conductive roll according to any one of claims 5 to 10.