JP3768243B2 - Semiconductive foam roll and process for producing the roll - Google Patents

Description

【００８７】
【表２】

注：電気抵抗率は、例えば、「２×１０の９乗」を「２Ｅ＋０９」と標記している。
【００８８】
比較例１
エピクロルヒドリンゴムの組成を表３に示すようにした（ＥＯ／ＥＣＨ＝３．８）こと、熱風炉ＨＡＶで架橋発泡させた以外は前記実施例１と同様に実験を行いスポンジロールを得た。さらに、ポリウレタン樹脂（第一工業製薬社製スーパーフレックス１５０、Ｔｇ４０℃）水分散液（固形分２０％）８０重量部と酸化スズ２０重量部をボールポットに入れ、良く分散させた。このコート材溶液にスポンジロールを浸漬させ、乾燥した、コート層の厚みは約５０μｍであった。さらに、ポリウレタン樹脂（第一工業製薬社製スーパーフレックス１２６、Ｔｇ７２℃）水分散液（固形分２０％）に上記コートロールを浸漬させ乾燥した。最外コート層の厚みは約１５μｍであった。このコートロールを１５０℃、３０分間熱処理した。その評価結果を表４に示す。
【００８９】
比較例２
前記実施例２においてＥＣＯと水添ＮＢＲとの比率を表３に示すようにしたこと、熱風炉ＨＡＶで架橋発泡したこと以外は実施例２と同様に実験を行い、コートロールを得た。その評価結果を表４に示す。
【００９０】
比較例３
表３に示す処方に変えた他は実施例２と同様にしてスポンジロールを得た。その評価結果を表４に示す。
【００９１】
【表３】

【００９２】
【表４】

【００９２】
（表１〜表４に共通の脚注）
＊１ ＮＢＲ：日本ゼオン社製 商品名「Ｎｉｐｏｌ １０５２ Ｊ」、アクリロニトリル・ブタジエン共重合ゴム、ヨウ素価２８０
＊２ 水添ＮＢＲ：日本ゼオン社製 商品名「Ｚｅｔｐｏｌ ２０２０」、水素化アクリロニトリル・ブタジエン共重合ゴム、ヨウ素価２８
＊３ ＳＢＲ：日本ゼオン社製 商品名「Ｎｉｐｏｌ １５００」、スチレン・ブタジエン共重合ゴム、ヨウ素価３２０
＊４ 老化防止剤 Ｄ：大内新興化学興業社製、アセトン−ジフェニルアミン反応生成物
＊５ ＯＢＳＨ：ｐ，ｐ'−オキシビス（ベンゼンスルホニル・ヒドラジド）
＊６ 導電性カーボン：ＫＥＴＪＥＮ ＢＬＡＣＫ ＴＮＴ．Ｃｏ，「ケッチェンブラック ＥＣ」
【００９３】
本発明の半導電性発泡ロールは、その電気抵抗率を導電性付与剤の配合によるのではなく、前記共重合体（Ａ）と不飽和ゴム（Ｂ）の配合割合で調整したものであるので、電気抵抗率のバラツキがなく、その制御も容易である。
【００９４】
共重合体（Ａ）と不飽和ゴム（Ｂ）とで発泡体層を形成したものは、小さなセルを持つ発泡体層を形成できる。
【産業上の利用可能性】
【００９５】
本発明の半導電性発泡ロールは、転写残りが少なく、感光体汚染も少なく、且つ耐圧縮性に優れており、さらに電気抵抗率が温度や湿度によって余り変化しないので、電子写真装置において、感光体ドラム外周面を一様に帯電させるための帯電ロールとして、感光体ドラム外周面の静電潜像をトナー像に現像するための現像ロールとして、現像ロールにトナーを供給するための供給ロールとして、またはトナー像を紙やＯＨＰシートに転写するための転写ロールなどとして好適に使用できる。【Technical field】
[0001]
The present invention relates to a semiconductive foam roll that can be used in an electrophotographic apparatus and the like, and more particularly, to obtain a stable semiconductivity without blending the conductivity-imparting particles, in terms of compression resistance, transferability, etc. The present invention relates to an excellent semiconductive foam roll and a method for producing the same.
[Background]
[0002]
An electrophotographic apparatus such as an electrophotographic copying machine or an electrophotographic printing machine forms an electrostatic latent image by uniformly charging the outer peripheral surface of the photosensitive drum and then exposing the outer peripheral surface of the photosensitive drum with a print pattern or a copy pattern. Then, a toner image is formed (developed) by attaching toner to the electrostatic latent image, and this toner image is transferred to a copy sheet or a print sheet to form an image (print or copy). is there.
[0003]
In the electrophotographic apparatus, the foam roll is used as a charging roll for uniformly charging the outer peripheral surface of the photosensitive drum, as a developing roll for developing the electrostatic latent image on the outer peripheral surface of the photosensitive drum into a toner image, and as a developing roll. It is used as a supply roll for supplying toner or as a transfer roll for transferring a toner image to paper or an OHP sheet.
[0004]
As foam rolls used in electrophotographic apparatuses, those made of urethane rubber, silicon rubber, natural rubber, chloroprene rubber, ethylene propylene diene rubber and the like are known.
The roll used in the electrophotographic apparatus is required to have a so-called medium resistance region (semiconductive region) whose electrical resistivity is in the range of 10 6 to 10 11 Ω · cm. .
[0005]
In conventional foam rolls, the electrical resistivity is controlled and adjusted by the blending amount of the conductivity imparting particles. However, in the middle resistance region, the change in electrical resistivity with respect to the change in the blending amount of the conductivity-imparting particles is large. Therefore, simply controlling the blending amount of the conductivity-imparting particles can cause variations in electrical resistivity (electrical resistance in the roll). The distribution of the rate and the variation of the electrical resistivity of each lot of foam rolls) are increased. In addition, when the conductivity imparting particles are blended in a large amount in order to reduce the electrical resistivity, the hardness of the foam roll increases. In the method using blending of conductivity imparting particles, it may be difficult to adjust the hardness and the electrical resistivity. In the foam roll, since the film portion forming the cell is thin, the dispersion state of the conductivity-imparting particles tends to greatly affect the electrical resistivity.
[0006]
Further, since the foam roll is brought into pressure contact with other rolls or the like, the cell may be crushed by the compressive force and the roll diameter may be reduced. For this reason, conventional foam rolls have not obtained sufficient characteristics in terms of transferability, photoconductor contamination, compression resistance, and the like.
DISCLOSURE OF THE INVENTION
[0007]
It is an object of the present invention to provide a semiconductive foam roll that has stable semiconductivity without blending conductivity imparting particles and is excellent in compression resistance and transferability.
[0008]
According to the present invention, in order to achieve the above object, at least a conductive core material and a foam layer covering the outer peripheral surface of the core material are provided, and the foam layer is an alkylene oxide unit.10-60Mol%, epihalohydrin units38-88Copolymer (A) comprising 2% by mole and 1 to 15% by mole of ethylenically unsaturated epoxide units15-90Part by weight and unsaturated rubber (B)10-85A foamed crosslinked product of a composition containing parts by weight (however, the total weight of the copolymer (A) and the unsaturated rubber (B) is 100 parts by weight).The unsaturated rubber is selected from acrylonitrile-butadiene copolymer rubber and its hydrogenated product, and styrene-butadiene copolymer rubber, and the foam layer has an Asker C hardness of 15 to 35 degreesA semiconductive foam roll is provided.
[0009]
Furthermore, according to the present invention, a step of forming a composition containing a rubber and a crosslinking agent into a tube shape,ObtainedSemiconductive foam having a step of crosslinking and foaming a tube-shaped composition by irradiation with microwaves to obtain a tubular foamed crosslinked product, and a step of inserting a conductive core material into the tube cavity of the foamed crosslinked product A process for producing a roll, wherein the rubber is an alkylene oxide unit10-60Mol%, epihalohydrin units38-88Copolymer (A) comprising 2% by mole and 1 to 15% by mole of ethylenically unsaturated epoxide units15-90Part by weight and unsaturated rubber (B)10-85Parts by weight (however, the total weight of copolymer (A) and unsaturated rubber (B) is 100 parts by weight)The unsaturated rubber (B) in the rubber is selected from acrylonitrile-butadiene copolymer rubber and hydrogenated product thereof, and styrene-butadiene copolymer rubber, and the foamed crosslinking The Asker C hardness of the product is 15 to 35 degreesA process for producing a semiconductive foam roll is provided.
[Brief description of the drawings]
[0010]
FIG. 1 is an axial sectional view of an example of a semiconductive foam roll according to the present invention, and FIG. 2 is an axial sectional view of another example of a foam roll according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0011]
Hereinafter, the embodiment of the present invention will be shown, and the configuration of the semiconductive foam roll of the present invention and the production method thereof will be specifically described.
[0012]
(I) Copolymer (A)
The copolymer (A) of the component used in the present invention is an alkylene oxide.10-60Mol%, epihalohydrin38-88It is a copolymer obtained by copolymerizing mol% and ethylenically unsaturated epoxide 2 to 15 mol%.
[0013]
As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide and the like can be used alone or in combination of two or more. When used in combination, ethylene oxide and propylene oxide are preferably used in combination. When ethylene oxide and propylene oxide are used in combination, the ratio of the two (ethylene oxide / propylene oxide) is usually used at a ratio of 10/90 to 90/10 (molar ratio), but preferably 1 or more.
[0014]
Copolymerization ratio of alkylene oxide in copolymer (A) is60If it exceeds mol%, the hygroscopicity becomes high, or the electrical dependency of the electrical resistivity increases, which is not preferable.
[0015]
Examples of the epihalohydrin include epichlorohydrin, epibromohydrin, epifluorohydrin, and the like. Among these, epichlorohydrin is preferable in view of availability.
[0016]
The copolymerization ratio of epihalohydrin in the copolymer (A) is88If it exceeds mol%, the electrical resistivity becomes high, which is not preferable for practical use.38If it is less than mol%, the hygroscopicity becomes high.
[0017]
Examples of the ethylenically unsaturated epoxide include allyl glycidyl ether, glycidyl methacrylate, glycidyl acrylate, butadiene monooxide, and the like. Of these, allyl glycidyl ether is preferred. By copolymerizing the ethylenically unsaturated epoxide, crosslinking with a sulfur-based crosslinking agent (sulfur or sulfur donor) or peroxide becomes possible, and the stain resistance and metal corrosion resistance are improved. When the copolymerization ratio of the ethylenically unsaturated epoxide in the copolymer (A) is outside the above range, it becomes difficult to obtain a smooth rubber sheet. The copolymerization ratio of the ethylenically unsaturated epoxide is preferably 2 to 10 mol%.
[0018]
(II) Unsaturated rubber (B)
In the present invention, when the unsaturated rubber (B) is blended with the copolymer (A), workability is remarkably improved, for example, the kneading time of the blend is significantly shortened. The unsaturated rubber (B) component used here is a rubber having an unsaturated bond in the molecule. The amount of unsaturated bonds in the molecule is usually 3 to 500, preferably 5 to 350, as evaluated by iodine value.In the present inventionAs such rubber, acrylonitrile-butadiene copolymer rubber(Hereafter referred to as “NBR”)andThatPartial hydrogenated product(Hereinafter, sometimes referred to as “hydrogenated NBR”) and rubber selected from styrene / butadiene copolymer rubber (hereinafter also referred to as “SBR”).
[0019]
Particularly preferred unsaturated rubbers in combination with the copolymer (A) are NBR and hydrogenated NBR.
[0020]
Further, when the foam layer is formed by using a rubber composition containing 5 to 40% by weight of an unsaturated rubber that is solid at normal temperature and 5 to 40% by weight of a liquid unsaturated rubber that is liquid at normal temperature as the unsaturated rubber. It is preferable because a roll exhibiting a moderately low electrical resistivity, a moderately low hardness, and little photoreceptor contamination can be obtained. The combination of the liquid unsaturated rubber and the solid unsaturated rubber is not particularly limited, but the same monomer-based copolymer rubber is preferably used. Specifically, a combination of solid NBR and liquid NBRIs a preferred exampleCan be mentioned.
[0021]
The copolymer (A) is used in an amount of 15 to 90% by weight, preferably 20 to 90 parts by weight, in 100 parts by weight of “copolymer (A) + unsaturated rubber (B)”.
[0022]
The unsaturated rubber (B) is used in an amount of 10 to 85 parts by weight, preferably 10 to 80 parts by weight, in 100 parts by weight of “copolymer (A) + unsaturated rubber (B)”.
[0023]
(III) Crosslinking agent
The crosslinking agent used in the present invention is capable of crosslinking the copolymer (A) and the unsaturated rubber (B). It is preferable to use a sulfur-based crosslinking agent or a peroxide as the crosslinking agent. By using these crosslinking agents, it is possible to prevent a roll made of foamed crosslinked rubber from contaminating the photoreceptor.
[0024]
Examples of the sulfur-based crosslinking agent include sulfur and sulfur donors that are usually used for crosslinking diene rubbers. Examples of the sulfur donor include thiuram compounds such as morpholine disulfide and tetramethylthiuram disulfide.
[0025]
Examples of the peroxide include dicumyl peroxide, di (t-butylperoxy) diisopropylbenzene, 2,5-di-t-butylperoxy-2,5-dimethylhexane, benzoyl peroxide, and the like.
[0026]
Further, a crosslinking aid may be used to increase the crosslinking efficiency by peroxide.
As the crosslinking aid, maleimide compounds are suitable, and specific examples include maleimide and phenylene bismaleimide. In addition to the maleimide compound, an acrylate or methacrylate polyfunctional monomer may be used.
[0027]
When a crosslinking agent other than a sulfur-based crosslinking agent or a compound other than a peroxide, such as a thiourea-based or amine-based compound, is used as the crosslinking agent, contamination of the photoreceptor due to the foamed crosslinked rubber layer of the foam roll tends to occur. Become.
[0028]
(IV) Foaming agent
Examples of the foaming agent for foaming the composition containing the copolymer (A) and the unsaturated rubber (B) include inorganic foaming agents such as sodium bicarbonate, ammonium bicarbonate, and ammonium carbonate, N, N′-dinitroso penta Nitroso compounds such as methylene tetramine, N, N′-dimethyl-N, N′-dinitroso terephthalamide, azodicarbonamide, azo compounds such as azobisisobutyronitrile, benzene sulfonyl hydrazide, P, Organic foaming agents such as sulfonyl hydrazide such as P'-oxybis (benzenesulfonyl hydrazide) are mentioned, but nitroso compounds, azo compounds, sulfonyl hydrazides that release nitrogen gas to produce fine closed-cell sponges It is particularly preferable to use an organic blowing agent such as
[0029]
A foaming aid may be used to increase the foaming efficiency of the foaming agent.
[0030]
Examples of the foaming aid include salicylic acid, urea and derivatives thereof.
The amount of the blowing agent used is usually 1 to 50 parts by weight with respect to 100 parts by weight of “copolymer (A) + unsaturated rubber (B)”. When the amount of the foaming agent used is small, foaming is insufficient, and when the amount used is large, the cell diameter becomes too large.
[0031]
(V) Production of roll
The roll of the present invention can be produced by the following various methods.
[0032]
(1) A method of inserting a semiconductive core material after forming, foaming, and crosslinking a foaming composition into a tube shape. Unsaturated rubber (B), copolymer (A), crosslinking agent, and foaming agent Are mixed to obtain a foaming composition, and the composition is formed into a tube shape using an extruder or the like. This extrusion can also be performed by core wire extrusion molding with a temporary core corresponding to the core material. After molding, heating is performed to decompose the foaming agent to generate a gas, which is then foamed. At the same time, the copolymer (A) and the unsaturated rubber (B) are crosslinked with a crosslinking agent to obtain a foamed crosslinked product. The heating temperature at this time is 120-250 degreeC normally. Heating may be performed in an oven or the like, but it is preferable to perform heating by self-heating by irradiation of microwaves and vibration of rubber molecules. According to microwave irradiation heating, the temperature of the composition is increased uniformly, so that the cell diameter becomes uniform and the variation in electrical resistivity is reduced. A conductive core material with an adhesive applied to the surface is inserted into the foamed cross-linked product thus obtained (after removing the temporary core, if used), if necessary.
[0033]
(2) Method for completing molding, foaming, and crosslinking of the foaming composition on the core material An adhesive is applied to the outer peripheral surface of the conductive core material, and the unsaturated rubber (B), A method for producing a crosslinked foamed molded article by forming from a foaming composition obtained by kneading a polymer (A), a crosslinking agent and a foaming agent into a tube shape using an extruder or the like and then performing foaming and crosslinking.
[0034]
(3) Method obtained by foaming rubber latex The latex obtained by blending the latex of copolymer (A) and the latex of unsaturated rubber (B) is foamed by mechanical stirring or a foaming agent, and then slowly coagulated. A method of forming a foam by gelling with an agent and heating to crosslink is utilized.
[0035]
The adhesive used to fix the foam layer and the core material is an adhesive in which a conductive filler is mixed with an arbitrary adhesive such as phenol resin, epoxy resin, acrylic resin, polyurethane or the like, or is itself semiconductive. Synthetic resin adhesive having
[0036]
The thickness of the adhesive layer is preferably 2 to 50 μm. If it is less than 2 μm, the foam layer is easy to peel off, and if it exceeds 50 μm, it is difficult to control the electrical resistivity. The electrical resistivity of the adhesive is preferably 10 10 Ω · cm or less. If it exceeds 10 10 Ω · cm, it becomes difficult to control the electrical resistivity of the roll.
[0037]
The electrical resistivity of the foam layer 2 is preferably in the range of 10 6 to 10 11 Ω · cm. If it is less than 10 6 Ω · cm, charge leakage tends to occur, and if it exceeds 10 11 Ω · cm, charging becomes insufficient.
[0038]
The layer thickness of the foam layer 2 is not particularly limited, but is usually preferably in the range of 1 to 10 mm. Furthermore, the cell diameter of the foam layer is usually 50 to 150 μm, and the Asuka hardness C is usually 15 to 35 degrees.Is. If the cell diameter of the foam layer is less than 50 μm, the hardness tends to increase, and if it exceeds 150 μm, the compression resistance tends to decrease. Asuka hardness C15If the temperature is less than 1, the compression resistance tends to decrease.35Exceeding the degree tends to increase the torque during roll rotation. The expansion ratio is usually 1.2 to 5 times.
[0039]
The semiconductive foam roll of the present invention is produced by inserting a conductive core material into the tube cavity of the foamed crosslinked product thus obtained.
[0040]
(VI) Formation of resin layers 3a and 3b on the foam layer
After the cross-linking molding, the resin layer 3 is preferably formed on the outer peripheral surface of the foam layer as necessary in order to reduce the environmental dependency of the semiconductive foam roll of the present invention and to prevent contamination of the photoreceptor. . Furthermore, before forming this resin layer, it is preferable to perform a polishing treatment in order to improve the dimensional accuracy and increase the smoothness of the surface. As a polishing method, a method of mechanically polishing using an abrasive is usually employed.
[0041]
Thus, after performing a grinding | polishing process as needed, the resin layer which consists of the resin layer 3, Preferably the below-mentioned inner layer 3a and the outer layer 3b is formed in the surface of the said foam layer 2. FIG.
[0042]
The inner layer and the outer layer are usually formed by applying and drying a resin solution or dispersion constituting each layer by brushing, spraying, dipping, or the like. Examples of the means for drying the resin layer include natural drying and heat drying. Among them, heat drying is preferable in order to improve the uniformity of the film thickness of the resin layer.
[0043]
Furthermore, it is preferable to reduce the frictional resistance by irradiating with ultraviolet rays as necessary to cure the surface.
[0044]
As resin which comprises the said resin layer, a polyurethane resin, a silicone resin, a polyamide resin, a polyester resin, a polyimide resin etc. are mentioned, for example, A polyurethane resin is mentioned suitably.
[0045]
The formation of the polyurethane resin layer is preferably carried out using a self-emulsifying or forced emulsifying polyurethane resin aqueous dispersion. Conventionally, a charging roll having a structure in which a surface of a roll is coated with a polyurethane resin is known. As a coating method, a method of immersing the roll in an organic solvent solution of a polyurethane resin has been adopted. However, the method using a polyurethane resin organic solvent solution is difficult to reduce the surface roughness of the polyurethane resin coating layer because of the high evaporation rate of the organic solvent in addition to the problem of environmental pollution due to the volatilization of the organic solvent. Furthermore, inconveniences such as swelling of the foam layer and extraction of the compounding agent from the foam layer are likely to occur.
[0046]
As the self-emulsifying type or forced emulsifying type polyurethane resin aqueous dispersion, a commercially available product can be used. The polyurethane resin may contain a functional group or a reactive group. There are also various types of film formation conditions for the aqueous dispersion, such as drying, thermosetting, and ultraviolet curing.
[0047]
The polyurethane resin that can be suitably used in the present invention is a reaction product of a polyfunctional isocyanate compound and a polyether polyol or polyester polyol. This polyurethane resin may have a hydrophilic functional group in the molecular chain.
[0048]
Examples of hydrophilic functional groups include hydroxyl groups and carboxyl groups.
[0049]
Examples of polyfunctional isocyanate compounds (that is, compounds having two or more isocyanate groups) include triphenylmethane triisocyanate, 4,4-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, tolylene diisocyanate, tetramethylxylene diisocyanate, and xylene diisocyanate. Aromatic isocyanates such as dicyclohexane diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like.
[0050]
Examples of the polyether polyol include polyoxytetramethylene glycol, polyethylene glycol, and polypropylene glycol. Examples of the polyester polyol include those having a hydroxyl group at the molecular end obtained by reacting a polyvalent carboxylic acid and a polyol (including polyether polyol), and also include polycarbonate diol.
[0051]
Examples of the polyvalent carboxylic acid include adipic acid, phthalic acid, sebacic acid, and dimer acid. Examples of the polyol include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, 1,3-butanediol, hexanetriol, trimethylolpropane, glycerin, pentaerythritol, sorbitol, and dicarboxylic acid glycol.
[0052]
A polyurethane resin having a molecular weight of usually 100,000 to 500,000, preferably 200,000 to 300,000 is used.
[0053]
Examples of the silicone resin that can be used as the resin constituting the resin layer include those modified with an acrylic group, an epoxy group, an ester group, or the like in addition to those having a methyl group or a phenyl group in the side chain.
[0054]
When the resin layer is formed of an inner layer and an outer layer, the glass transition temperature (Tgi) of the resin of the inner layer is usually 10 to 60 ° C., preferably 15 to 40 ° C. By making Tgi within this range, the adhesion between the outer layer and the foam layer is improved.
[0055]
In addition, the thickness of the inner layer is preferably in the range of 5 to 100 μm in order to improve the adhesion between the foam layer and the outer layer, and the electrical resistivity is to reduce variation in the electrical resistivity of the entire foam roll. 10 6 to 10 11 Ω · cm is preferable.
[0056]
When the resin layer is formed of an inner layer and an outer layer, the glass transition temperature (Tgo) of the resin in the outer layer is usually 35 to 90 ° C, preferably 40 to 80 ° C. When a resin having a glass transition temperature (Tgo) of less than 35 ° C. is used, toner adhesion occurs, and when a resin having a glass transition temperature (Tgo) of more than 90 ° C. is used, cracks occur in the coating, making it unusable. .
[0057]
Further, if the thickness of the outer layer is less than 5 μm, the durability against wear decreases, and if it exceeds 50 μm, cracks are likely to occur in the coating, so a range of 5 to 50 μm is preferable, and its electrical resistivity is the same as that of the inner layer. 6 to 10 11 Ω · cm is preferable.
[0058]
Further, the glass transition temperature of the resin constituting the inner layer and the outer layer is preferably in a relationship of Tgi + 10 ° C. <Tgo, since it is difficult to balance the durability and the toner adhesion unless they are separated by 10 ° C. or more. .
[0059]
In the present invention, a differential thermal analyzer (DSC) is employed as a method for measuring the glass transition temperature.
[0060]
In the present invention, the thickness of the resin layer (in the case of a resin layer composed of an inner layer and an outer layer, the total layer thickness of the inner layer and the outer layer) is usually 10 to 150 μm, preferably 10 to 120 μm. If the thickness of the resin layer is less than 10 μm, poor charging tends to occur, and if it exceeds 150 μm, the production efficiency of the foam roll tends to decrease.
[0061]
In order to fit the electronic device, the semiconductive foam roll of the present invention has an outer peripheral surface from the core material (the outer peripheral surface of the resin layer when there is a resin layer, the outer peripheral surface of the foam layer when there is no resin layer). The electrical resistivity up to 10 6 to 10 11 Ω · cm is preferable.
The core material 1 used in the present invention is usually made of a conductive rigid body. Examples of the conductive rigid body include metals such as stainless steel and copper.
[0062]
The core material 1 may be made of a solid body or may be made of a hollow body. In addition, examples of the shape of the core material 1 include a cylindrical shape,FIG.As shown in the figure, the outer diameter of the central portion in the axial direction is the largest, and the outer diameters of both end portions are small. Since it can prevent that the pressing force of becomes small compared with both ends, it is preferable.
[0063]
FIG.As shown in the figure, the central part is cylindrical and both ends are tapered in diameter,FIG.The one shown in Fig. 1 is a straight one with a constant outer diameter.
[0064]
FIG.In the core material 1, the outer diameter of the central part of the core material is usually 4 to 40 mm. Moreover, although the outer diameter of both ends of a core material can be suitably selected by the elasticity of the foam layer 2 from a core material to a roll outer peripheral surface, it is 3-30 mm normally. The length of the core material is usually 150 to 300 mm. The range in which both ends are reduced in diameter is usually 5 to 100 mm.
[0065]
The outer peripheral surface of the core material 1 is preferably increased in surface roughness by polishing or the like in order to improve the bonding with the foam layer 2 that covers the outer peripheral surface.
[0066]
A shaft rod is formed coaxially with the core material from both ends of the core material.
[0067]
The shaft rod is usually of an outer diameter that is the same as or smaller than the outer diameter of the both ends of the core body. The shaft rod is usually formed in a cylindrical shape, and may be provided with a groove in the circumferential direction as needed so that it can be easily installed on the bearing. The core material may be a structure in which the shaft rod and the core material main body are integrated, or the shaft rod and the core material main body may be composed of separate structures and assembled.
[0068]
When the foam layer is formed on the outer peripheral surface of the core material having the largest outer diameter at the central portion in the axial direction and the outer diameter at both ends, the outer periphery of the charging roll is formed from the outer peripheral surface of the core material. The foam layer up to the surface is thickly laminated at both ends and thinly laminated at the axially central portion. By increasing the thickness of both ends, the distance between the core material made of the rigid body and the other roll surface, etc. is increased, and a thick foam is interposed between them. It is absorbed by the body and wear can be reduced.
[0069]
The thickness of the central portion of the foam layer is usually 0.5 to 5 mm, the thickness of both end portions corresponds to the reduced diameter of the core material body, and the outer diameter of the entire foam roll is from the both end portions to the central portion. Are preferably equal to each other.
[0070]
Hereinafter, the present invention will be described with reference to examples and comparative examples, but the present invention is not limited thereto.
[0071]
The rubber property evaluation method employed in this example and the property evaluation method as a transfer roll are shown below.
[0072]
(Hygroscopic)
The obtained sponge roll is precisely weighed to 0.1 g in advance, left in an environment of 35 ° C. and 80% RH for 72 hours, and the weight is measured again. The weight increase was divided by the original weight and multiplied by 100, and the rate of increase (%) was taken as a measure of hygroscopicity. Smaller hygroscopicity is better. When calculating the increase rate, the weight of the core is measured in advance and subtracted.
[0073]
(Electric resistivity)
An electrode having a width of 1 inch is wound around the obtained roll, and a resistance value is measured by applying a DC voltage of 500 V between the electrode and the core material. At this time, a ground electrode having a width of 0.5 inch is wound around both sides of the pre-wound electrode by 1 mm to perform grounding. The electrical resistivity is calculated from the measured resistance value according to the following formula.
ρ (Ω · cm) = (2 × π × 2.54 × measured resistance value) / log (roll diameter / core material diameter)
[0074]
Measurement environment conditions are L / L conditions of low temperature and low humidity (10 ° C., 20% RH), H / H conditions of high temperature and high humidity (35 ° C., 80% RH), N / N conditions of normal temperature and normal humidity (23 ° C., 50% % RH). Further, 20 sponge rolls were prepared for each experiment, and all of the resistance values thereof were measured. The average value of each of L / L and H / H, and the maximum value and the minimum value of N / N measured values were measured. Values are shown in Tables 2 and 4.
[0075]
(Foamed cell diameter)
Cut the slices thinly with a razor so that the produced transfer roll is perpendicular to the core, take a photograph with a 100 × optical microscope, read the photograph with a Nexus 9000 type image processing device, An average value and a standard deviation value were calculated by taking 100 values obtained by dividing the sum of the long diameter and the short diameter by 2.
[0076]
(Transcription remaining)
After 2,000 continuous prints, the transfer residue on the photosensitive drum after the black solid portion transfer process is peeled off with a mending tape, and the tape is affixed to a white sheet. The difference from the reflectivity of only the mending tape affixed to the white paper was determined.
○: Transfer remaining less than 15%
Δ: Transfer remaining is 15% or more and less than 20%
X: Transfer remaining 20% or more (photoconductor contamination)
[0077]
The transfer roll was brought into contact with the photoreceptor so as to have a load of 500 g and left in an environment of 45 ° C. and 80% RH for 4 weeks to evaluate the presence or absence of photoreceptor contamination.
◎ ・ ・ Contamination is not observed after 4 weeks.
○: Contamination is not observed after 3 weeks, but then a slight streak is observed on the photoreceptor.
Δ: Contamination is not observed after 2 weeks, but then streaks are observed on the photoreceptor.
× · Contamination is observed before 2 weeks.
[0078]
(Compression resistance)
The transfer roll was brought into contact with the photoreceptor so as to have a deformation rate of 20%, and was left in an environment of 45 ° C. and 80% RH for 3 weeks to evaluate whether the deformation of the roll due to the pressing was restored after the pressing was released.
○: Compression set is less than 10%
Δ: Compression set is 10% or more and less than 20%
X: Compression set rate is 20% or more
[0079]
Example 1
Epichlorohydrin rubber (EO / ECH = 1.4), NBR, additives, crosslinking agent and foaming agent with the formulation shown in Table 1 are kneaded using a Banbury mixer and extruded into a tube shape with an inner diameter of about 6 mm and an outer diameter of about 15 mm. Molding was performed. This tube was subjected to cross-linking foaming using a microwave continuous cross-linking apparatus (UHF.CV) to obtain a foam-molded product. The microwave continuous cross-linking device consists of a combination of a UHF heating section and a secondary heating section (hot air furnace HAV). The conditions of the UHF heating section are set to a temperature in the tank of 180 ° C., a UHF frequency of 2450 MHz and an output of 0.3 KW. The conditions of the HAV section were set by setting the temperature in the tank to 200 ° C. and adjusting the transport speed so that the UHF section was 2.5 minutes and the HAV section was 5 minutes.
[0080]
A 6 mmφ × 280 mm stainless steel core material, to which an adhesive had been applied in advance, was press-fitted into the obtained foamed molded article and bonded at 120 ° C. for 30 minutes. The surface of the obtained foam was polished to obtain a sponge roll of 15 mmφ × 250 mm. ThatEvaluationThe results are shown in Table 2.
[0081]
Example2
In Example 1, the unsaturated rubber was changed from NBR to hydrogenated NBR, and an experiment was performed in the same manner as in Example 1 to obtain a sponge roll. Furthermore, polyurethane resin (Daiichi Kogyo Seiyaku superflex 150, Tg 40 ° C.) aqueous dispersion (solid content 20%)
[0082]
80 parts by weight and 20 parts by weight of tin oxide were placed in a ball pot and dispersed well to obtain a coating material solution. A sponge roll was immersed in this coating material solution and dried. The thickness of the coat layer was about 50 μm. Furthermore, the said coating roll was immersed in the polyurethane resin (Daiichi Kogyo Seiyaku superflex 126, Tg72 degreeC) aqueous dispersion (solid content 20%), and it dried. The thickness of the outer coat layer was about 15 μm. This coated foam roll was heat-treated at 150 ° C. for 30 minutes. ThatEvaluationThe results are shown in Table 2.
[0083]
Example3
Extrusion molding was performed in a tube shape in the same manner as in Example 1, and crosslinking and foaming were performed using a hot air furnace HAV continuous crosslinking apparatus to obtain a foam molded product. HAV conditions were adjusted by adjusting the conveyance speed so that the temperature in the tank was heated at 220 ° C. for 5 minutes. A sponge roll was obtained using the obtained foam in the same manner as in Example 1. ThatEvaluationThe results are shown in Table 2.
[0084]
Example4
In Example 1, a sponge roll was obtained in the same manner as in Example 1 except that the unsaturated rubber was changed from NBR to SBR. The results are shown in Table 2.
[0085]
Example5
The sample was irradiated with ultraviolet rays for 3 minutes while rotating the sponge roll obtained in Example 1 with a lamp output of 80 / cm, a rated power of 4 kW, and a distance of 12 cm from an ultraviolet lamp near a wavelength of 280 nm. Of sponge rolls treated with UV irradiationEvaluationThe results are shown in the table.
[0086]
[Table 1]

[0087]
[Table 2]

Note: For electrical resistivity, for example, “2 × 10 9” is labeled “2E + 09”.
[0088]
Comparative Example 1
The composition of the epichlorohydrin rubber was set as shown in Table 3 (EO / ECH = 3.8), and a sponge roll was obtained in the same manner as in Example 1 except that the foam was crosslinked and foamed in a hot air furnace HAV. Furthermore, 80 parts by weight of a polyurethane resin (Superflex 150, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Tg 40 ° C.) aqueous dispersion (solid content 20%) and 20 parts by weight of tin oxide were placed in a ball pot and dispersed well. A sponge roll was immersed in this coating material solution and dried. The thickness of the coating layer was about 50 μm. Furthermore, the said coating roll was immersed in the polyurethane resin (Daiichi Kogyo Seiyaku superflex 126, Tg72 degreeC) aqueous dispersion (solid content 20%), and it dried. The thickness of the outermost coating layer was about 15 μm. This coat roll was heat-treated at 150 ° C. for 30 minutes. ThatEvaluationThe results are shown in Table 4.
[0089]
Comparative Example 2
Example2Example 3 except that the ratio of ECO to hydrogenated NBR was as shown in Table 3 and that the foam was cross-linked and foamed in a hot stove HAV.2An experiment was conducted in the same manner as above to obtain a coat roll. ThatEvaluationThe results are shown in Table 4.
[0090]
Comparative Example 3
Except for changing to the formulation shown in Table 3, Examples2In the same manner, a sponge roll was obtained. ThatEvaluationThe results are shown in Table 4.
[0091]
[Table 3]

[0092]
[Table 4]

[0092]
(Footnotes common to Tables 1 to 4)
* 1 NBR: Product name “Nipol 1052 J” manufactured by Zeon Corporation, acrylonitrile-butadiene copolymer rubber, iodine value 280
* 2 Hydrogenated NBR: Product name “Zetpol 2020” manufactured by Zeon Corporation, hydrogenated acrylonitrile-butadiene copolymer rubber, iodine value 28
* 3 SBR: Product name “Nipol 1500” manufactured by Zeon Corporation, styrene-butadiene copolymer rubber, iodine value 320
* 4 Anti-aging agent D: Ouchi Shinko Chemical Industry Co., Ltd., acetone-diphenylamine reaction product
* 5 OBSH: p, p'-oxybis (benzenesulfonyl hydrazide)
* 6 Conductive carbon: KETJEN BLACK TNT. Co, “Ketjen Black EC”
[0093]
Since the semiconductive foam roll of the present invention has its electrical resistivity adjusted by the blending ratio of the copolymer (A) and the unsaturated rubber (B), not by blending the conductivity imparting agent. There is no variation in electrical resistivity, and its control is easy.
[0094]
What formed the foam layer with the copolymer (A) and the unsaturated rubber (B) can form a foam layer having small cells.
[Industrial applicability]
[0095]
The semiconductive foam roll of the present invention has little transfer residue, little photoreceptor contamination, excellent compression resistance, and electrical resistivity does not change much with temperature and humidity. As a charging roll for uniformly charging the outer peripheral surface of the photosensitive drum, as a developing roll for developing the electrostatic latent image on the outer peripheral surface of the photosensitive drum into a toner image, and as a supply roll for supplying toner to the developing roll Or a transfer roll for transferring a toner image to paper or an OHP sheet.

Claims (18)

At least a conductive core material and a foam layer covering the outer peripheral surface of the core material, the foam layer comprising 10 to 60 mol% of alkylene oxide units, 38 to 88 mol% of epihalohydrin units and ethylenically unsaturated a copolymer consisting of epoxide units 2 to 15 mol% (a) 15 to 90 parts by weight unsaturated rubber (B) 10 to 85 parts by weight (however, the copolymer (a) and the unsaturated rubber and (B) Ri Do foamed crosslinked product of a composition total weight containing 100 parts by weight), the unsaturated rubber, acrylonitrile-butadiene copolymer rubber and a hydrogenated product thereof, and a styrene-butadiene copolymer rubber A semiconductive foam roll , characterized in that the foam layer has an Asker C hardness of 15 to 35 degrees . The semiconductive foam roll according to claim 1, wherein the unsaturated rubber is selected from acrylonitrile-butadiene copolymer rubber and a hydrogenated product thereof. The semiconductive foam roll according to claim 1, wherein the epihalohydrin is epichlorohydrin. The semiconductive foam roll according to any one of claims 1 to 3, wherein the ethylenically unsaturated epoxide is allyl glycidyl ether. Foamed cross-linked product, semi-conductive foamed roll according to any one of claims 1-4 is obtained by crosslinking using sulfur-based crosslinking agent or a peroxide. Foamed cross-linked product, semi-conductive foamed roll according to any one of claims 1-5 is obtained by foaming using the organic blowing agent. The semiconductive foam roll according to any one of claims 1 to 6, wherein the electrical resistivity of the foam layer is 10 6 to 10 11 Ωcm. The semiconductive foam roll according to any one of claims 1 to 7, wherein the foam layer has a thickness of 1 to 10 mm. The semiconductive foam roll according to any one of claims 1 to 8 , wherein the cell diameter of the foam layer is 50 to 150 µm. The semiconductive foam roll according to any one of claims 1 to 9 , wherein the hygroscopicity of the foam layer is 0.2 to 0.3 . The semiconductive foam roll according to any one of claims 1 to 10, wherein a resin layer is laminated on the outer peripheral surface of the foam layer. The semiconductive foam roll according to claim 11 , wherein the resin layer is formed of polyurethane. The resin layer is composed of an inner layer and an outer layer, the glass transition temperature of the resin forming the inner layer is 10 to 60 ° C., the glass transition temperature of the resin forming the outer layer is 35 to 90 ° C., and the resin forming the inner layer The semiconductive foam roll according to claim 11 or 12, which is higher by 10 ° C or more than the glass transition temperature. The semiconductive foam roll according to any one of claims 1 to 13, wherein the outer diameter of the central portion in the axial direction of the core material is the largest, and the outer diameters of both ends are small. The semiconductive foam roll according to any one of claims 1 to 14, wherein the unsaturated rubber comprises an unsaturated rubber that is solid at room temperature and a liquid unsaturated rubber that is liquid at room temperature. A step of forming a composition containing rubber and a cross-linking agent into a tube shape, a step of obtaining a tube-like foamed cross-linked product by irradiating the obtained tube-shaped composition with microwaves to cross-link and foam, and conducting A method for producing a semiconductive foam roll comprising a step of inserting a conductive core material into a tube cavity of the foamed crosslinked product, wherein the rubber comprises 10 to 60 mol% of alkylene oxide units, 38 to 88 mol% of epihalohydrin units and ethylene. a copolymer consisting of 2 to 15 mol% sexual unsaturated epoxide units (a) 15 to 90 parts by weight unsaturated rubber (B) 10 to 85 parts by weight (provided that the copolymer (a) and the unsaturated rubber (B ) total weight of the consists 100 parts by weight), unsaturated rubber (B) is an acrylonitrile-butadiene copolymer rubber and a hydrogenated product of the rubber, and styrene- It is those selected from Tajien copolymer rubber, and semi-conductive foam roll process, wherein the Asker C hardness of the foam crosslinked product is 15 to 35 degrees. The process for producing a semiconductive foam roll according to claim 16 , comprising a step of fixing the foam layer and the core material with an adhesive. The method for producing a semiconductive foam roll according to claim 16 or 17 , wherein foaming is performed at a foaming ratio of 1.2 to 5 times.

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