JPH0987344A - Rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optimum rubber composition for forming the outermost layer of a developing roller, etc., whose function is to prevent toner filming from occurring. SOLUTION: This is a rubber composition whose matrix component is a fluororubber and in which particles formed from a mold release agent are dispersed in the fluororubber matrix. The mold release agent is at least either of a reactive silicone oil or a reactive fluorooil and the particles formed from the mold release agent are fixed by reaction in the fluororubber matrix and the cross-sectional areas of the articles with diameters not less than 0.1μm are measured and when the data are accumulated in the ascending order, a particle size corresponding to 90% of the total cumulative cross-sectional area is not more than 30μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition containing fluororubber as a base material, and more specifically, to a rubber composition most suitable for forming an outermost layer of a roll such as a developing roll which comes into contact with a toner. It is about things.

[0002]

2. Description of the Related Art In an electrophotographic copying machine or the like, for a roll which comes into contact with toner, such as a developing roll, it is required to prevent the toner from adhering to the roll surface as an important characteristic. Therefore, the outermost layer of such a roll is formed by using a fluororubber composition having excellent mold releasability, and in order to further improve the releasability, the fluororubber composition has a release agent. Contains silicone oil.

[0003]

However, since the fluororubber and the silicone oil have poor compatibility, the silicone oil may be present in the fluororubber matrix in the form of large aggregates. In such a state, for example, in the developing roll of an electrophotographic copying machine, the supply of silicone oil to the roll surface becomes uneven,
As a result, toner adheres to the portion where the silicone oil is deficient, and this causes the toner to spread further, and eventually toner filming occurs.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a rubber composition capable of forming the outermost layer of a roll having excellent toner releasability.

[0005]

In order to achieve the above object, the rubber composition of the present invention contains fluororubber as a matrix component, and particles formed from a release agent are dispersed in the fluororubber matrix. A rubber composition, wherein the release agent is at least one of reactive silicone oil and reactive fluorine oil, particles formed from the release agent are reactively fixed in the fluororubber matrix, and When the cross-sectional area of the above-mentioned particles having a particle size of 0.1 μm or more is measured and these are sequentially accumulated from the smallest one,
The particle size of the particles at the point where the cumulative cross-sectional area is 90% of the total cumulative cross-sectional area is 30 μm or less.

In the present invention, "the particles are reactively fixed" means that fluororubber molecules constituting the matrix,
Reacts with reactive silicone oil that forms particles,
It means that both are chemically bonded and fixed. It is not necessary that all reactive silicone oils, etc. chemically bond with the fluororubber, and if the reactive silicone oil, etc. mainly located on the surface of the particles chemically bond, the release agent particles will be reactively fixed in the fluororubber matrix. Is done. Further, the fluororubber matrix includes both a state in which fluororubber molecules are not crosslinked and a state in which they are crosslinked by vulcanization. Therefore, the rubber composition of the present invention may be unvulcanized or vulcanized.

In the present invention, the "particle size is 0.1 μm"
The case where the cross-sectional area of the above-mentioned particles of m or more is measured and these are sequentially accumulated from the smallest one "means the following case. That is, in the fluororubber composition, the cross-sectional area of particles having a particle size of 0.1 μm or more distributed therein is measured. The particle size refers to the maximum particle size of the particles. For example, if the cross-sectional shape of the particles is circular, the diameter is the particle diameter, and if the cross-sectional shape of the particles is elliptical, the major axis is the particle diameter. And this measurement can be performed by observing a fluororubber composition with a scanning electron microscope, for example. Further, this observation does not have to be performed for the entire rubber composition, and may be partially performed by deciding an observation location (sampling location). The sampling points are preferably 4 to 30 points, particularly preferably 20 to 30 points. The calculation of the cross-sectional area is performed according to the cross-sectional shape of the particles. For example, the particle cross-section can be obtained by dividing the particle cross-section into small areas and calculating the area of each part. Then, this cross-sectional area is sequentially accumulated from the smallest one, and the total cumulative cross-sectional area is calculated.

Then, "90 for this total cumulative cross-sectional area
The particle size at the point where the cumulative cross-sectional area in% is 30 μm
“Below” means the following. That is, the cumulative cross-sectional area of 90% of the total cumulative cross-sectional area is derived. Then, the particle size of particles at the point where the cumulative cross-sectional area is 90% (hereinafter referred to as "90% cumulative cross-sectional area particle size") is obtained. An example of this is shown in the graph of FIG. In this graph, the vertical axis is the cumulative cross-sectional area ratio (%), and the horizontal axis is the particle size (μm) and the particle cross-sectional area (μm ² ). As shown in the figure, when particles are sequentially accumulated from the one having a small cross-sectional area, a curve is obtained in which the cumulative cross-sectional area ratio increases as the particle diameter (cross-sectional area) increases. Then, as indicated by the dotted line, the particle size of the particles at the point corresponding to the 90% cumulative cross-sectional area is obtained. If the particle size of the particles at this point is 30 μm or less, the requirements of the present invention are satisfied.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the present invention specifies the state of the release agent in the fluororubber matrix in the fluororubber composition. That is, at least one of reactive silicone oil and reactive fluorine oil is used as a release agent, and particles of this release agent are reactively fixed in the fluororubber matrix. Figure 1
As shown in the schematic diagram of 1., particles 2 formed of reactive silicone oil or the like in the fluororubber matrix 1
Are chemically bonded by reacting with the fluororubber molecule 1a. This chemical bond differs depending on the type of reactive group such as reactive silicone oil. And, as mentioned earlier,
The particle size distribution of the particles 2 is 90% cumulative cross-sectional area particle size of 30.
It becomes less than μm and is uniformly dispersed. By doing so, for example, when the outermost layer of the developing roll is formed by using this rubber composition, the reactive silicone oil or the like, which is the release agent, does not exude into a large aggregate. As a result, this developing roll maintains high toner releasability for a long period of time, and toner filming is prevented from occurring.

Next, the present invention will be described in detail.

The rubber composition of the present invention contains a fluororubber and at least one of a reactive silicone oil (component A) and a reactive fluorine oil (component B).

The above-mentioned fluororubber is not particularly limited, and conventionally known ones are used, but tetrafluoroethylene-polypropylene (TFE-PP) is used because of its low polymer viscosity and good dispersibility of the filler. ) It is preferable to use a copolymer, and it is particularly preferable to use a random copolymer having a structure represented by the following general formula (1).

[0013]

Embedded image

In the above formula (1), the ratio of each repeating portion m, n, p is a weight ratio of m: n: p = (30 to
60) :( 10-40): It is preferable to use those set to (10-40), and particularly preferably, m:
n: p = (30 to 50) :( 30 to 40) :( 20 to 3)
0).

Next, the above-mentioned reactive silicone oil (component A) and reactive fluorine oil (component B) to be blended with the above-mentioned fluororubber are toner release agents, and both of the components A and B are blended. Alternatively, either one of the above two components may be blended alone.

Both the above-mentioned reactive silicone oil (component A) and reactive fluorine oil (component B) are at least selected from the group consisting of hydroxyl group, amino group, mercapto group, epoxy group, carboxyl group and methacryl group. Those having one reactive group are preferred. These reactive groups react with the fluororubber, whereby the particles formed from the oil are fixed in the fluororubber matrix. This reaction fixation (chemical bond)
The mode of is shown below for each reactive group.

[Hydroxyl group]

Embedded image

[Amino group]

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[Mercapto group]

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[Epoxy group]

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[Carboxyl group]

[Chemical 6]

[Methacrylic group]

[Chemical 7]

These reactive groups are located at the ends (including both ends) and side chains of the molecular chain and differ depending on the type of oil and the like.

Among the above-mentioned reactive groups, a hydroxyl group, an amino group and a mercapto group are preferable because of their good reactivity with fluororubber, and an amino group is particularly preferable. For thermal stability, the reactive silicone oil (A component) preferably has an average molecular weight of 300 or more, and the reactive fluorine oil (B component) preferably has an average molecular weight of 200 or more, particularly preferably both. Is 1
It is 500 to 20,000. Furthermore, these reactive silicone oil (A component) and reactive fluorine oil (B
The total compounding ratio (A + B) of the components) is 100
It is preferably in the range of 0.5 to 100 parts, and particularly preferably in the range of 15 to 50 parts, relative to parts by weight (hereinafter abbreviated as "part").

Specific examples of such reactive silicone oil (component A) and reactive fluorine oil (component B) are shown below.

[Reactive Silicone Oil Having Hydroxyl Group]

Embedded image

[Reactive Silicone Oil Having Amino Group]

Embedded image

[Reactive Silicone Oil Having Mercapto Group]

Embedded image

[Reactive Silicone Oil Having Epoxy Group]

Embedded image

[Reactive Silicone Oil Having Carboxyl Group]

[Chemical 12]

[Reactive Silicone Oil Having Methacrylic Group]

Embedded image

[Reactive Fluorine Oil Having Hydroxyl Group]

Embedded image

[Reactive Fluorine Oil Having Amino Group]

[Chemical 15]

[Reactive Fluorine Oil Having Mercapto Group]

Embedded image

[Reactive Fluorine Oil Having Epoxy Group]

Embedded image

[Reactive Fluorine Oil Having Carboxyl Group]

Embedded image

[Reactive Fluorine Oil Having Methacrylic Group]

Embedded image

Among the reactive silicone oils (component A) and reactive fluorine oils (component B) shown in the above specific examples, those having a hydroxyl group, an amino group or a mercapto group are preferable from the viewpoint of reactivity. And particularly preferred are those having an amino group.

Next, in the rubber composition of the present invention, in addition to the reactive silicone oil (component A) and reactive fluorine oil (component B), a non-reactive silicone oil (component C) and non-reactive fluorine are added. Oil (component D) can be added. These non-reactive silicone oils and non-reactive fluoro oils do not have a reactive group for reaction fixation in the fluoro rubber matrix, but when used in combination with the above reactive silicone oils, etc. Fixed. This is because non-reactive silicone oil and the like are mixed in particles formed from reactive silicone oil and the like, and both are bonded by a hydrophobic bond.
It is assumed that non-reactive silicone oil or the like is fixed in the fluororubber matrix. Therefore, even if a non-reactive silicone oil or the like is used, if it is a predetermined amount, there is no possibility that large agglomerates thereof will be generated.

The above non-reactive silicone oil (component C)
Is preferably one having at least one organic group selected from the group consisting of an alkyl group, an aralkyl group, a higher alcohol ester group, and a polyether fluoroalkyl group. This is because these are highly effective as a release agent.

Among the above-mentioned non-reactive silicone oils, those having an average molecular weight of 500 to 100,000 are preferable, and particularly preferable are those having an average molecular weight of 2,000 to 50,000, because of their high releasability and thermal stability. It is in the range of.

The blending ratio of the non-reactive silicone oil is usually 10 to 1 per 100 parts of fluororubber.
It is set in the range of 00 parts, preferably in the range of 20 to 50 parts, particularly preferably in the range of 30 to 40 parts.

Specific examples of such a non-reactive silicone oil are shown below.

[Non-Reactive Silicone Oil Having Alkyl Group]

Embedded image

[Non-Reactive Silicone Oil Having Aralkyl Group]

[Chemical 21]

[Non-Reactive Silicone Oil Having Higher Alcohol Ester Group]

Embedded image

[Non-Reactive Silicone Oil Having Polyether Fluoroalkyl Group]

Embedded image

Among the non-reactive silicone oils shown as these specific examples, because of its high releasability,
Those containing an alkyl group, a higher alcohol ester group, or a polyether fluoroalkyl group are preferably used, and those having a higher alcohol ester group are particularly preferable.

As the non-reactive fluorine oil (component D), perfluoropolyether or the like is used.

The rubber composition of the present invention contains the above-mentioned reactive silicone oil (component A), reactive fluorine oil (component B), non-reactive silicone oil (component C) and non-reactive fluorine oil (D). In addition to the (component), an ionic conductive agent can be added for the purpose of imparting an appropriate volume electric resistance (10 ⁷ to 10 ¹² Ω · cm). The characteristic relating to the volume electric resistance is important as the characteristic of the outermost layer of the developing roll, for example.

Examples of the ionic conductive agent include trimethyl octadecyl ammonium chloride, benzyl trimethyl ammonium chloride, trioctyl propylene ammonium chloride, trioctyl propyl ammonium bromide, trimethyl octadecyl ammonium perchlorate, tetrabutyl ammonium hydrogen sulfate, tetrabutyl ammonium. Quaternary ammonium compounds such as hydroxide and perchlorates and benzoates of these quaternary ammonium compounds,
Examples thereof include nitrite, sulfate, and hydroxide. These may be used alone or in combination of two or more. Above all,
It is preferable to use tetrabutylammonium hydrogen sulfate (TBAHS) or tetrabutylammonium hydroxide.

In addition to the above ion conductive agents, acid acceptors such as calcium hydroxide, magnesium oxide, calcium oxide, red lead, and litharge, and vulcanizing agents such as peroxide, bisphenol A, bisphenol AF, and hexamethylenediamine. Can be appropriately blended as necessary. As will be described later, it is preferable that the vulcanizing agent be blended each time the rubber composition of the present invention is used (before coating).

Next, the rubber composition of the present invention can be produced by using the above-mentioned material, for example, by the following method (first method).

That is, first, the fluororubber is kneaded in a closed kneader (for example, Banbury mixer). An acid acceptor is added to this, and after kneading, reactive silicone oil (A component) and reactive fluorine oil (B component)
At least one of the above, non-reactive silicone oil (C component), non-reactive fluorine oil (D component) and other components are added as necessary, and kneading is continued. Then, after the torque of the kneader increases, the kneading is stopped and the kneaded product is taken out. Then, this kneaded product is sheeted with an open roll. Then, this is dissolved in a solvent to prepare a rubber composition (coating liquid). Examples of the solvent include ethyl acetate, methyl ethyl ketone, methanol, toluene, isopropyl alcohol, methyl cellosolve,
Examples include dimethylformamide. These may be used alone or in combination of two or more. At this stage, it is preferable that the vulcanizing agent is not compounded but compounded before use (before coating).

The rubber composition of the present invention can be prepared by the following method (second method) in addition to the above-mentioned manufacturing method.

That is, first, the fluororubber is dissolved in a solvent. Examples of the solvent include ethyl acetate, methyl ethyl ketone, methanol, toluene, isopropyl alcohol, methyl cellosolve, and dimethylformamide. These may be used alone or in combination of two or more. Then, at least one of the reactive silicone oil (component A) and the reactive fluorine oil (component B), and optionally a non-reactive silicone oil (component C) and a non-reactive fluorine oil, in the dissolved fluororubber. (D
Ingredients) and other ingredients. Then, stirring is performed under heating to increase the viscosity, and when the viscosity becomes constant, the stirring is stopped to prepare a rubber composition (coating liquid). The heating conditions are preferably in the range of 40 ° C or higher and not higher than the boiling point of the solvent, and particularly preferably in the range of 50 to 80 ° C. At the time of this adjustment, no vulcanizing agent was added,
It is preferable to mix before use (before coating). It is speculated that the increase in viscosity during stirring is due to the finer particles of the reactive silicone oil or the like (increasing the total surface area) and the chemical bonding between the reactive silicone oil and the fluororubber molecules. The constant viscosity is usually 2000 to 20000 cps, and preferably 3000 to 5000 cps, although it varies depending on the material used.

In the rubber composition thus obtained,
Particles formed of reactive silicone oil or the like (release agent) in the fluororubber matrix are uniformly dispersed with a 90% cumulative cross-sectional area particle size of 30 μm or less, and the fluororubber matrix ) Is immobilized by reaction (see FIG. 1). As a result, as mentioned above,
Releasability can be maintained for a long period of time without generation of large aggregates of reactive silicone oil or the like. The particle size of the particles is preferably 0.1 to 20 μm,
Particularly preferably, it is 0.1 to 5 μm.

Next, an example in which this rubber composition is applied to the formation of the outermost layer of the developing roll will be shown.

The developing roll may have a three-layer structure as shown in FIG. As shown in the drawing, this developing roll is provided with an innermost layer 11 formed of an elastic body, an intermediate layer 12 and an outermost layer 13 formed of a fluororubber composition on the outer periphery of a shaft body 10 such as a cored bar. .

The developing roll having the three-layer structure is manufactured as follows. That is, first, materials for forming the innermost layer and the intermediate layer are prepared.

The components of the materials for forming the innermost layer and the intermediate layer are not particularly limited, and conventionally known ones are used.

For example, as each component of the material for forming the innermost layer, ethylene-propylene rubber (EPDM), styrene-butadiene rubber (SBR), silicone rubber, polyurethane elastomer, and the like in which carbon black is blended can be mentioned.

As each component of the material for forming the intermediate layer,
For example, EPDM, SBR, nitrile rubber, hydrogenated nitrile rubber, polyurethane elastomer, polyester, N-methoxymethylated nylon, and the like mixed with a conductive agent such as carbon black, metal oxide, and quaternary ammonium salt. .

As a method for preparing the materials for forming the innermost layer and the intermediate layer, a conventionally known method is applied. To give an example of this, first, the innermost layer forming material (compound)
Is prepared by kneading the above components with a kneader such as a kneader. In addition, the material for forming the intermediate layer (coating liquid)
Is prepared by kneading with a ball mill, rolls or the like, adding a solvent to this mixture, and mixing and stirring.

Then, the innermost layer and the intermediate layer are formed on the outer periphery of the shaft by a conventional method to prepare a roll substrate. For example, as shown in FIG. 7, the lower lid 15 on which the shaft body 10 is set
Then, a compound-like innermost layer forming material is cast into the cylindrical mold 16, and the upper lid 17 is fitted onto the cylindrical mold 16. In this state, the entire roll die is heated (vulcanization treatment, conditions: 150-
200 ° C. × 20 to 40 minutes) to form the innermost layer. Then, the shaft body on which the innermost layer is formed is released from the mold, and the residue of the vulcanizing agent is removed by evaporation if necessary. Then, the intermediate layer forming material (coating liquid) is applied to the outer peripheral surface of the innermost layer, and drying and heat treatment (vulcanization treatment, condition: 120 to 200 ° C. × 1)
0 to 30 minutes) to form an intermediate layer. The above coating is
Conventionally known coating methods such as a dipping method, a spray method and a roll coating method can be applied. In this way, a roll substrate having the innermost layer and the intermediate layer formed on the outer periphery of the shaft body is manufactured.

On the other hand, a vulcanizing agent is added to the rubber composition (coating liquid) of the present invention. Then, the rubber composition is applied to the outer peripheral surface of the intermediate layer of the roll substrate. This coating method is not particularly limited, and a conventional method such as a dipping method, a spray method or a roll coating method can be applied.
Then, after the coating, drying and heat treatment (vulcanization treatment, conditions: 150 to 200 ° C. × 20 to 40 minutes) are performed to remove the solvent in the rubber composition by evaporation and to crosslink the fluororubber component. . In this way, a developing roll having a three-layer structure as shown in FIG. 6 can be manufactured. In this developing roll, the thickness of each layer is appropriately determined, but the thickness of the innermost layer is preferably set in the range of 2 to 10 mm, particularly preferably 3 to 6 mm. The thickness of the intermediate layer is preferably set in the range of 3 to 90 μm, and particularly preferably 5 to 15 μm. The thickness of the outermost layer is preferably 20 to 100 μm, particularly preferably 30 to 70 μm.

In this way, a developing roll having the outermost layer formed using the rubber composition of the present invention can be prepared, but the present invention is not limited to this. That is, the rubber composition of the present invention is capable of imparting excellent toner releasability to the roll surface for a long period of time. Applicable. Examples of such a roll include a fixing roll and the like.

[0068]

As described above, the rubber composition of the present invention
A rubber composition in which particles formed of a reactive silicone oil or the like are dispersed in a fluororubber matrix,
The particle size distribution of the above particles is 90%, and the cumulative cross-sectional area particle size is 30 μm.
The range is as follows, and the particles are reactively fixed in the fluororubber matrix. Therefore, it is possible to prevent the generation of large aggregates of silicone oil, which is a toner release agent, and the exudation onto the roll surface, which are problems in the outermost layer of the conventional developing roll. As a result, for example, in the developing roll having the outermost layer formed by using the rubber composition of the present invention, the occurrence of toner filming is prevented and a good quality copied image can be obtained for a long time.

Next, examples will be described together with comparative examples.

First, prior to Examples and Comparative Examples, a core metal (diameter 10 mm, made of SUS304) to be a shaft, a liquid silicone rubber to which carbon black was added as an innermost layer forming material, and an intermediate layer forming material A product obtained by adding carbon black to hydrogenated nitrile rubber was prepared.

Then, according to the above-mentioned method, the innermost layer and the intermediate layer were formed on the outer circumference of the shaft body to prepare a roll substrate.

[0072]

Examples 1 to 7 and Comparative Examples 1 to 4 The outermost layer was formed on the outer peripheral surface of the roll substrate by the second method described above. That is, the materials shown in Tables 1 to 3 below were mixed in the proportions shown in the same table, and a fluororubber composition was prepared according to the second method described above. Then, using this fluororubber composition, the outermost layer was formed on the outer peripheral surface of the roll base by the above-mentioned method (coating method: roll coating method), and a desired developing roll was produced. The innermost layer of this developing roll has a thickness of 5 mm, the intermediate layer has a thickness of 10 μm, and the outermost layer has a thickness of 50 μm.

With respect to the developing rolls of Examples 1 to 7 and Comparative Examples 1 to 4 thus obtained, evaluation of copied images and occurrence of toner filming were examined by the following methods. The results are also shown in Tables 1 to 3 below. Further, in the same table, the average particle size of the particles and the 90% cumulative cross-sectional area particle size are also shown. The 90% cumulative cross-sectional area grain size was measured by the method described below.

[Evaluation of Copy Image] The developing roll was incorporated in an electrophotographic copying machine to actually perform copying. Then, the image quality of the copied image was visually evaluated at the initial stage of copying and after copying 30,000 sheets. That is, the characters are printed and there is no problem in the copied image,
The fine lines were clearly copied, and the fine lines and fogging were marked with x. It should be noted that the faint means that the fine line is broken, and the fog means that the toner is scattered in a place where there is no image. In addition, when toner filming occurred, evaluation was performed separately for a portion where toner filming occurred and a portion where toner filming did not occur.

[Toner Filming] The thick toner on the surface of the developing roll has poor chargeability, resulting in a defective copy image. Specifically, if a part of the toner component adheres to the surface of the developing roll with a thickness of 1 μm or more, the image is significantly deteriorated. Therefore, when the toner adhesion is 1 μm or more, the toner filming is considered to have occurred.

[90% cumulative cross-sectional area particle size] As shown in FIG. 9 (A), two breaks are formed in the elastic body portion (inner layer, intermediate layer, outermost layer) of the developing roll 20 at right angles to the axial direction. It was cut into slices, further cut in the axial direction, taken out from the core metal, and a sample 20a as shown in FIG. Then, as shown in the cross-sectional view of the sample 20a in the same figure (C), observation was performed with a scanning electron microscope (S-4100, manufactured by Horiba, Ltd.) at four locations (outermost layer portions) surrounded by dotted lines. . Then, the 90% cumulative cross-sectional area grain size was automatically determined by using the image processor (Spica II, manufactured by Nippon Avionics Co., Ltd.) according to the procedure described above.

[0077]

[Table 1]

[0078]

[Table 2]

[0079]

[Table 3]

From the above Tables 1 and 2, the developing rolls of Examples 1 to 7 in which the particles of reactive silicone oil etc. have a 90% cumulative cross-sectional area particle size of 30 μm or less, have no problem in copied images, and Fine lines were clearly copied, and toner filming did not occur. On the other hand, from Table 3 above, in the developing rolls of Comparative Examples 1 to 4 in which the 90% cumulative cross-sectional area particle size of the particles of reactive silicone oil etc. exceeds 30 μm, toner filming occurs, and in this part, The copied image was bad.

Next, the state of the particles formed from the reactive silicone oil in the outermost layer of the developing rolls of Example 1 and Comparative Example 1 was examined by using the scanning electron microscope, and the results are shown in FIGS. Shown in the photo.

FIG. 2 is a photograph showing the condition of the outermost layer surface of the developing roller of Example 1 (magnification: 10,000 times), and FIG. 3 is a photograph showing the condition of the same outermost layer inside (axial cross section) ( Magnification 1
10,000 times). FIG. 4 is a photograph (magnification: 10,000 times) showing the state of the outermost layer surface of the developing roll of Comparative Example 1.
Is a photograph (magnification: 10,000 times) showing a state inside the same outermost layer (cross section in the axial direction). From the photographs of FIGS. 2 and 3, in the developing roll of Example 1, the particles formed from the reactive silicone oil had a very small particle size of about 1 μm or less, and were uniformly dispersed in the fluororubber matrix. I understand. On the other hand, from the photographs of FIGS. 4 and 5, it can be seen that in the developing roll of Comparative Example 1, the particle size of the particles formed from the reactive silicone oil is large.

Particles formed from the reactive silicone oil dispersed in the fluororubber matrix were comprehensively judged from the results of these electron microscope observations and the results (toner filming) of Tables 1 to 3 above. It can be said that toner filming was prevented in the developing roller of the example because the 90% cumulative cross-sectional area particle size of No. 3 was 30 μm or less and the particles were reactively fixed in the fluororubber matrix.

[Brief description of drawings]

FIG. 1 is a schematic view showing a microscopic structure of a rubber composition of the present invention.

FIG. 2 is a photograph showing the structure of particles formed from reactive silicone oil on the surface of the outermost layer of the developing roll that is an example of the present invention.

FIG. 3 is a photograph showing the structure of particles formed from a reactive silicone oil inside the outermost layer of the developing roll that is an example of the present invention.

FIG. 4 is a photograph showing the structure of particles formed from reactive silicone oil on the surface of the outermost layer of a conventional developing roll.

FIG. 5 is a photograph showing the structure of particles formed from a reactive silicone oil inside the outermost layer of a conventional developing roll.

FIG. 6 is a cross-sectional view showing the structure of a developing roll.

FIG. 7 is a cross-sectional view showing a method of manufacturing a developing roll.

FIG. 8 is a graph showing the relationship between the particle size of particles and the cumulative cross-sectional area ratio of particles.

9A is a perspective view showing a state in which a developing roll is cut, FIG. 9B is a perspective view of a sample cut out from the developing roll, and FIG. 9C is a sectional view of the sample. .

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[Procedure amendment]

[Submission date] October 2, 1995

[Procedure Amendment 1]

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[Figure 5]

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C08L 51/06 LLE C08L 51/06 LLE F16C 13/00 9037-3J F16C 13/00 B G03G 15/08 501 501 G03G 15/08 501D // C08G 81/00 NUU C08G 81/00 NUU (72) Inventor, Akihiko Kaji, Omaki, Komaki City, Aichi Prefecture

Claims (6)

[Claims] 1. A rubber composition comprising fluororubber as a matrix component, wherein particles formed from a release agent are dispersed in the fluororubber matrix, wherein the release agent is a reactive silicone oil and a reactive fluorine. It is at least one of oils, particles formed from the release agent are reactively fixed in the fluororubber matrix, and the cross-sectional area of the particles having a particle size of 0.1 μm or more is measured. A rubber composition having a particle size of 30 μm or less at the point where the cumulative cross-sectional area is 90% of the total cumulative cross-sectional area when the particles are sequentially accumulated. 2. The reactive silicone oil is a reactive silicone oil having at least one reactive group selected from the group consisting of hydroxyl group, amino group, mercapto group, epoxy group, carboxyl group and methacryl group,
The rubber composition according to claim 1, wherein the reactive fluorine oil has at least one reactive group selected from the group consisting of a hydroxyl group, an amino group, a mercapto group, an epoxy group, a carboxyl group and a methacryl group. Stuff. 3. The rubber composition according to claim 1, wherein the reactive silicone oil has an average molecular weight of 300 to 150,000 and the reactive fluorine oil has an average molecular weight of 200 to 20,000. 4. The total blending ratio of the reactive silicone oil and the reactive fluorine oil is such that the fluororubber 10
0.5 to 100 parts by weight with respect to 0 parts by weight.
The rubber composition according to any one of items 1 to 3. 5. The rubber composition according to claim 1, wherein the particles formed from the release agent contain at least one of non-reactive silicone oil and non-reactive fluorine oil. 6. The rubber composition according to claim 5, wherein the non-reactive silicone oil has a higher alcohol ester group, and the non-reactive fluorine oil is perfluoropolyether.