JPH11272043A - Semiconducting rubber roll and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconducting rubber roll of low hardness which causes no contamination of a photoreceptor, which has little environmental dependence and excellent durability and resistance against compressive permanent strain. SOLUTION: The multilayered semiconducting rubber roll is produced by sequentially forming at least three layers in the order from the center, (A) an axial body 14, (B) an intermediate layer 15 and (C) a surface layer 16. The intermediate layer 15 is produced by crosslinking an epichlorohydrin rubber compsn. containing (a) a rubber component essentially comprising epichlorohydrin rubber (having >=50 wt.% epichlorohydrin rubber content), (b) a low mol.wt. epichlorohydrin polymer having 0.01 to 0.5 ηsp /C (by 10 to 150 pts.wt. to 100 pts.wt. of the epichlorohydrin rubber), and (c) a crosslinking agent (by 0.1 to 10 pts.wt. to 100 pts.wt. of the rubber component).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductive rubber roll used in an electrophotographic copying machine and the like and an image forming apparatus having the same. More particularly, the roll hardness is low and stable, and the permanent compression resistance and durability are improved. The present invention relates to a semiconductive rubber roll excellent in such properties as an image forming apparatus having the same.

[0002]

2. Description of the Related Art An electrophotographic copying machine or an electrophotographic printing machine forms an electrostatic latent image by uniformly charging the outer peripheral surface of a photoreceptor drum and then exposing a print pattern or a copy pattern on the outer peripheral surface of the photoreceptor. Then, a toner image is formed by attaching toner to the electrostatic latent image to form a toner image, and the toner image is transferred to a printing sheet or a copy sheet to perform printing or copying.

Conventionally, in the charging step of a photoreceptor, charging has generally been performed by corona discharge. However, there is a problem that the cost is high and harmful substances such as ozone are generated. Therefore, a charging method using a charging roll has been proposed.
In this charging method, a voltage is applied to a charging roll arranged in contact with the photoconductor, and a charge is directly applied to the photoconductor to charge the surface of the photoconductor. Even in the transfer step, a method has been proposed in which transfer is performed by using a transfer roll to apply a voltage to generate an electric field and move toner from a photoconductor to printing paper without using corona discharge. On the other hand, in the method using a non-magnetic one-component toner, the photoconductor and the developing roll are arranged so as to contact each other, and the toner conveyed by the developing roll is charged by friction between the developing roll and the developing blade. Let me do. The charged toner moves from the developing roll to the photoconductor in accordance with the electric field generated between the developing roll and the photoconductor, and the latent image is developed.

In such an image forming apparatus using a structure in which the photoconductor and the roll are in contact with each other, a rubber roll having a structure in which a rubber layer is formed on the surface of a shaft is used as the roll. A voltage must be applied between these rubber rolls and the photoreceptor to generate an electric field. Therefore, the electrical resistance of the rubber roll is required to be semiconductive.

[0005] Such a semiconductive rubber roll is generally a semiconductive rubber roll prepared by dispersing a conductivity imparting agent such as carbon black, carbon fiber or metal powder in a resin or rubber. However, in such a roll, the dispersion of the conductivity-imparting agent is lacking in uniformity, the magnitude of the electric resistance varies depending on the location, and the volume resistivity is 10 ⁶ to 10 ¹² Ω · cm. It is very difficult to adjust to the area. Therefore, it has been proposed to use epichlorohydrin rubber which has a volume resistivity of 10 ⁷ to 10 ¹¹ Ω · cm itself and does not require the addition of a conductivity-imparting agent. However, epichlorohydrin rubber has a problem that the toner adheres to the surface and is easily stained due to poor surface releasability.

[0006] There has also been proposed one in which a non-adhesive coating layer made of a conductive fluororesin or the like is formed outside the epichlorohydrin rubber layer to prevent toner from adhering (Japanese Patent Laid-Open No. Hei 6-1994).
266206). However, there is a problem in that the hardness is not sufficiently low, and the durability in continuous printing such as scraping of the photoreceptor and toner deterioration is not sufficient.

In order to reduce the hardness of the semiconductive rubber roll, liquid acrylonitrile-butadiene rubber,
A method of adding a liquid unsaturated rubber such as liquid polybutadiene and liquid chloroprene has been proposed (Japanese Patent Laid-Open No. 9-1 / 1991).
No. 60354). However, the compatibility between the epichlorohydrin rubber and the liquid unsaturated rubber is not sufficient, and the compression set resistance is poor.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a low-hardness semiconductive rubber roll which is free from contamination of a photoreceptor, has little environmental dependency, and has excellent durability and compression set resistance. is there. More specifically, an object of the present invention is to provide an image forming apparatus for developing an electrostatic latent image on a photoreceptor into a visible image by using a toner, a developing roll, a charging roll, and a transfer roller arranged in contact with the photoreceptor. An object of the present invention is to provide a semiconductive rubber roll that can be suitably used as a roll or the like.

The present inventors have conducted intensive studies, and as a result, have found that a shaft body,
A semiconductive rubber roll having at least a three-layer structure of an intermediate elastic layer and a surface layer, and using, as a material of the intermediate elastic layer, a crosslinked product of a composition containing epichlorohydrin rubber and a low molecular weight epichlorohydrin polymer. Shows an appropriate roll electrical resistance without blending a conductivity-imparting agent,
It has been found that even when a resin layer having a thickness that can withstand practical use is provided on the surface layer, it has low hardness and excellent compression distortion resistance. The semiconductive rubber roll does not wear the photoconductor and does not contaminate it. Further, the toner is less deteriorated and has excellent durability. The present invention has been completed based on these findings.

[0010]

Thus, according to the present invention, (A) a shaft body, (B) (a) a rubber component containing epichlorohydrin rubber as an essential component, and (b) a low molecular weight epichlorohydrin in order from the central axis. An intermediate elastic layer formed by crosslinking an epichlorohydrin-based rubber composition containing a (c) crosslinking agent and a (C) cross-linking agent; and (C) a multilayer semiconductive rubber roll having at least three surface layers. An image forming apparatus having a semiconductive rubber roll is provided.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Shaft) The semiconductive rubber roll of the present invention has a shaft at the center. The shaft used in the present invention is not particularly limited as long as it is used as a shaft of a semiconductive rubber roll, but is usually made of a conductive rigid body. Examples of the conductive rigid body include metals such as stainless steel and copper.

The shaft may be made of a solid body or a hollow body. The size and shape may be determined according to the purpose of use. The shaft is shown in FIGS. 1 and 2.
It is preferable that the shape is a perfect cylinder like a shaft shown in FIG. This is because the adhesiveness between the layer laminated on the shaft body, generally the outer peripheral surface of the shaft body in contact with the intermediate elastic layer and the laminated layer, and the nip pressure when the roll is brought into contact with the photoreceptor become uniform. However, the shape of the shaft is not particularly limited as long as the adhesiveness and the nip pressure are within allowable ranges. For example, the outer diameter of the central part in the axial direction is the largest, and the outer diameter of both ends is small, so that the bending of the axial body is reduced. A smaller one can also be used. It is preferable to increase the surface roughness of the outer peripheral surface of the shaft body by polishing or the like in order to improve the adhesion with the layer laminated on the outer peripheral surface.

(Material of Inner Layer) The semiconductive rubber roll generally has a structure in which the outer peripheral surface of the shaft and the inner peripheral surface of the intermediate elastic layer are in contact with each other. An inner layer made of a conductive material is provided between the two. Is also good. When the inner layer is provided, the electric resistance of the roll can be adjusted by changing the thickness of the inner layer.

The conductive material serving as the material of the inner layer is not particularly limited, and a conductive resin or rubber, or a conductive agent such as carbon black, carbon fiber, metal powder or the like dispersed in the resin or rubber to be semiconductive. It may be a composition or the like prepared in a neutral manner.

(Material of Intermediate Elastic Layer) The semiconductive rubber roll of the present invention has an intermediate elastic layer formed outside the shaft body. This intermediate elastic layer is composed of (a) a rubber containing epichlorohydrin rubber as an essential component. Component (b) is a crosslinked product of an epichlorohydrin rubber composition containing a low molecular weight epichlorohydrin polymer and (c) a crosslinking agent.

(Rubber component) The rubber component (a) used in the present invention contains epichlorohydrin rubber as an essential component, and can be used in combination with other rubbers.

The epichlorohydrin rubber is a homopolymer rubber of epichlorohydrin or a copolymer rubber obtained by copolymerizing epichlorohydrin with an alkylene oxide and / or an unsaturated epoxide.

As the alkylene oxide, for example,
Saturated alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and isobutylene oxide; substituted saturated alkylene oxides such as epifluorohydrin, epibromohydrin, and trifluoromethylethylene oxide; each alone, or Two or more can be used in combination. Among these, ethylene oxide and propylene oxide are preferable from the viewpoint of availability. When using ethylene oxide and propylene oxide in combination, the ratio of both (ethylene oxide / propylene oxide) is a molar ratio, preferably from 10/90 to
90/10, more preferably 15 / 85-85 / 15,
Particularly preferably, it is 20/80 to 80/20.

Examples of the unsaturated epoxide include unsaturated alkylene oxides such as butadiene monooxide, 1,2-epoxy-5-hexene and 1,2-epoxy-7-octene; and glycidyl ethers such as allyl glycidyl ether. Glycidyl methacrylate;
Glycidyl esters such as glycidyl acrylate;
And the like. Of these, allyl glycidyl ether is preferred. By copolymerizing the unsaturated epoxide, cross-linking with a sulfur-based cross-linking agent (sulfur or sulfur donor) or peroxide becomes possible, and stain resistance and metal corrosion resistance are improved.

The amount of the alkylene oxide unit in the epichlorohydrin rubber is preferably from 0 to 70 mol%, more preferably from 10 to 65 mol%, particularly preferably from 20 to 70 mol%.
60 mol%. If the amount of the alkylene oxide unit in the epichlorohydrin-based rubber is too large, it may not be used depending on the environment because the hygroscopicity is increased or the environment dependence of the volume resistivity value is increased.

The amount of the epichlorohydrin unit in the epichlorohydrin rubber is preferably from 30 to 100 mol%,
More preferably 35 to 90 mol%, even more preferably 4
0 to 80 mol%. If the amount of epichlorohydrin unit in the epichlorohydrin rubber is too large, the volume resistivity increases, and if it is too small, the hygroscopicity increases.

The amount of unsaturated epoxide units in the epichlorohydrin rubber is preferably 0 to 15 mol%, more preferably 1 to 12 mol%, and particularly preferably 2 to 10 mol%.
It is. If the amount of the unsaturated epoxide unit in the epichlorohydrin rubber is too large, it is difficult to obtain a low-hardness crosslinked product. If the amount of the unsaturated epoxide unit is too small, the crosslinking with the sulfur-based crosslinking agent or peroxide may be insufficient.

As the epichlorohydrin rubber, a rubber having a Mooney viscosity at 100 ° C. of preferably 20 to 200, more preferably 40 to 150, and particularly preferably 50 to 100 is used because kneading in processing is easy.

The method for producing epichlorohydrin rubber is as follows.
It is not particularly limited, and can be produced by a known solution polymerization method using, for example, an organoaluminum compound-based catalyst described in JP-B-56-51171.

The rubber which can be used as an optional component of the rubber component (a) used in the production of the intermediate elastic layer includes, for example, acrylonitrile-butadiene copolymer rubber, acrylonitrile-isoprene copolymer rubber, acrylonitrile-butadiene-isoprene. Copolymer rubber, styrene-butadiene copolymer rubber and hydrogenated products thereof,
Ethylene-propylene-diene copolymer rubber, chloroprene rubber, acrylic rubber, fluorine rubber, urethane rubber and the like can be mentioned.

The blend ratio of the epichlorohydrin-based rubber to other rubbers is generally 5%.
0-100% by weight, preferably 60-90% by weight, particularly preferably 70-85% by weight, optional rubber 0-50
%, Preferably 10 to 40% by weight, particularly preferably 15 to 30% by weight. If the amount of the optional rubber is too large, the compatibility with the low-molecular-weight epichlorohydrin-based polymer is deteriorated. If the amount is too small, the effect of adding the optional rubber is hard to be obtained.

The blend of the epichlorohydrin-based rubber and the optional rubber may be mixed using a usual kneader such as a roll or a Banbury mixer.

(Low molecular weight epichlorohydrin polymer)
The low molecular weight epichlorohydrin polymer used in the present invention is a polymer having an epichlorohydrin unit as an essential component. The low molecular weight epichlorohydrin-based polymer may contain a monomer unit copolymerizable with epichlorohydrin, and examples of the monomer serving as such a unit include an alkylene oxide and an unsaturated epoxide. As the alkylene oxide and the unsaturated epoxide, those described as monomers of the epichlorohydrin rubber are used.

(B) The amount of epichlorohydrin unit in the low molecular weight epichlorohydrin polymer is preferably from 30 to
It is 100 mol%, more preferably 35 to 100 mol%, particularly preferably 40 to 100 mol%. As the epichlorohydrin unit amount increases, the volume resistivity value of the intermediate elastic layer increases, and as the epichlorohydrin unit amount decreases, production of a low molecular weight epichlorohydrin polymer becomes more difficult. The amount of the alkylene oxide unit is preferably from 0 to 70 mol%, more preferably from 0 to 65 mol%, particularly preferably from 0 to 60 mol%. The smaller the amount of alkylene oxide unit, the higher the volume resistivity, and the larger the amount, the more difficult the production. The amount of unsaturated epoxide units is preferably from 0 to 20 mol%, more preferably from 0 to 15 mol%, particularly preferably from 0 to 10 mol%.
Mol%. If the unsaturated epoxide unit content is too small, the low molecular weight epichlorohydrin polymer tends to elute from the epichlorohydrin rubber when a sulfur crosslinking agent or a peroxide is used as the crosslinking agent. On the other hand, if the amount of the unsaturated epoxide unit is too large, it is difficult to produce a low molecular weight epichlorohydrin polymer.

The low molecular weight epichlorohydrin polymer is in a liquid state at normal temperature (20 to 30 ° C.), and its molecular weight is preferably 1,000 to 10,000, more preferably 1500 to 8,000, and particularly preferably 2,000 to 2,000.
6000. The low molecular weight epichlorohydrin polymer usually has a Mooney viscosity of 1 or less, and is often too small to be measured. Reduced viscosity of low molecular weight epichlorohydrin polymer in toluene solution (η _sp
/ C) is preferably 0.01 to 0.5, more preferably 0.02 to 0.4, and particularly preferably 0.03 to 0.3. If η _sp / C is too large, the effect of lowering the hardness of the rubber is small, and if η _sp / C is too small, bleeding may occur.

The method for producing the low molecular weight epichlorohydrin polymer is not particularly limited. For example, it is produced by a known solution polymerization method using a catalyst such as stannic chloride, an organic aluminum / water complex, or a boron fluoride / ether complex. it can.

(Crosslinking Agent) Examples of the crosslinking agent (c) include sulfur or sulfur donors, organic peroxides, mercaptotriazines and thioureas. Examples of the sulfur donor include thiurams such as morpholine disulfide and tetramethylthiuram disulfide. Examples of the organic peroxide include ketone peroxides, peroxyesters, diacyl peroxides, and alkyl peroxides.When these organic peroxides are used, a crosslinked product having good compression set resistance is obtained. can get. Examples of thioureas include thiourea, dibutylthiourea, and triethylthiourea.

(Epichlorohydrin Rubber Composition) The epichlorohydrin rubber composition used in the present invention comprises (a)
A rubber component containing epichlorohydrin rubber as an essential component,
It contains (b) a low molecular weight epichlorohydrin polymer and (c) a crosslinking agent.

(B) The amount of the low molecular weight epichlorohydrin polymer is preferably from 10 to 150 parts by weight, more preferably from 2 to 100 parts by weight of the epichlorohydrin rubber.
0 to 120 parts by weight, particularly preferably 30 to 100 parts by weight. (B) If the amount of the low molecular weight epichlorohydrin-based polymer is too small, the hardness of the epichloroline-based rubber composition after crosslinking becomes too high. If the amount is too large, (b) the low molecular weight epichlorohydrin-based polymer will bleed or the viscosity will be high, and it will be difficult to prepare rubber compositions such as kneading.

The amount of (c) the cross-linking agent depends on the amount of (a) rubber component 10
0.1 to 10 parts by weight, more preferably 0.2 to 7 parts by weight, particularly preferably 0.3 to 0 parts by weight.
-5 parts by weight.

[0036] The epichlorohydrin rubber composition may optionally be mixed with a usual rubber compounding agent such as a crosslinking accelerator, a reinforcing agent, a filler and an antioxidant.

The epichlorohydrin rubber composition can be obtained by mixing the above-mentioned components using a usual kneader such as a roll or a Banbury mixer.

Crosslinking of the epichlorohydrin rubber composition can be carried out by heating to 100 to 250 ° C. using a usual rubber processing and molding machine such as a press, a steam pot, and an injection molding machine.

When this epichlorohydrin rubber composition is crosslinked, the low molecular weight epichlorohydrin polymer does not bleed out, and the hardness (Duro-A) is preferably 40 or less, more preferably 35 or less, and particularly preferably 30 or less. A crosslinked product used for the elastic layer can be easily obtained.

The epichlorohydrin rubber composition used in the present invention has low viscosity and dimensional stability, and is therefore suitable for extrusion molding and injection molding.

The layer thickness of the intermediate elastic layer is not particularly limited, and the roll electric resistance can be changed by changing the layer thickness.
The layer thickness is preferably 50 μm or more, more preferably 10 μm.
It is at least 0 μm, particularly preferably at least 200 μm. If the layer thickness is too small, the electric resistance of the roll becomes too small, and the durability of the intermediate elastic layer becomes a problem. Further, the layer thickness is preferably 30 mm or less, more preferably 20 mm or less,
Particularly preferably, it is 15 mm or less. If the layer thickness is too large, the electric resistance of the roll becomes too high.

The crosslinked product of the epichlorohydrin rubber composition forming the intermediate elastic layer in the present invention has semiconductivity. Usually, the cross-linked product has a volume resistivity of 10 ⁵ to 10 ¹² Ω · c.
m, preferably 10 ⁶ to 10 ¹¹ Ω · cm, more preferably 10 ⁷ to 10 ¹⁰ Ω · cm.

(Material of Surface Layer) A resin layer or a rubber layer is formed on the surface of the intermediate elastic layer. The resin layer or rubber layer is preferably a semiconductive resin layer or rubber layer. Moreover, it is good also as a crosslinked resin layer or a crosslinked rubber layer as needed.

The resin constituting the surface layer is not particularly limited, and resins used as the surface layer in general semiconductive rubber rolls, for example, polyurethane resin, silicone resin, polyamide resin, polyester resin, polyimide resin, fluorine resin And the like.

The polyurethane resin used as the resin constituting the surface layer is a reaction product of a polyfunctional isocyanate compound and a polyether polyol or a polyester polyol. This polyurethane resin may have a hydrophilic functional group in the molecular chain. The coating of the polyurethane resin is preferably carried out using a self-emulsifying or forced emulsifying polyurethane resin aqueous dispersion, since the environmental pollution is small and the compounding agent does not elute from the rubber layer without swelling the rubber layer. .

Examples of the silicone resin that can be used as the resin constituting the resin layer include those having a methyl group and a phenyl group in the side chain, and those modified with an acryl group, an epoxy group, an ester group, and the like.

Among the nylon resins that can be used as the resin constituting the resin layer, N-methoxymethylated nylon is preferable. N-methoxymethylated nylon is 6
-It is obtained by methoxymethylating an amide group of nylon, and the solubility in alcohol is improved by increasing the methoxylation rate.

When the resin layer is used, the thickness of the surface layer is preferably 5 to 300 μm, more preferably 7 to 200 μm.
m, more preferably in the range of 10 to 150 μm.
If the layer thickness is too small, the durability against abrasion decreases, and if it is too large, cracks tend to occur in the coating.

When the surface layer is a rubber layer, the rubber forming the rubber layer is not particularly limited, and a rubber used for forming the surface layer in a general semiconductive rubber roll is used. Acrylonitrile butadiene copolymer rubber, ethylene propylene diene copolymer rubber,
Synthetic rubbers such as epichlorohydrin rubber, urethane rubber, and fluoro rubber are used alone or as a blend.

When a rubber layer is used as the surface layer, the thickness of the surface layer is not particularly limited because there is no problem of cracking compared with the case of resin.

The volume specific resistance of the surface layer is preferably 10 ⁵ to 10 ¹² Ω · in order to reduce the variation in electric resistance.
cm, more preferably 10 ^5.5 to 10 ¹¹ Ω · cm, and still more preferably 10 ⁶ to 10 ¹⁰ Ω · cm. Carbon black such as acetylene black; conductive oxides such as tin oxide and zinc oxide; conductivity-imparting agents such as surfactants;
The volume specific resistance value is adjusted by adding, for example.

It is preferable that a plasticizer or a softening agent is not used in the resin or rubber constituting the surface layer from the viewpoints of photoconductor contamination and bleeding.

(Semiconductive Rubber Roll) The semiconductive rubber roll of the present invention comprises (A) a shaft body, (B)
(A) a rubber component containing epichlorohydrin rubber as an essential component, (b) a low molecular weight epichlorohydrin polymer, and (c) an intermediate elastic layer formed by crosslinking an epichlorohydrin rubber composition containing a crosslinking agent; ) A multilayer having at least three surface layers.

As a specific example, the semiconductive rubber roll shown in FIGS. 1 and 2 will be described. FIG. 1 is a sectional view perpendicular to an axis showing an example of a semiconductive rubber roll of the present invention, and FIG. 2 is an axial sectional view showing an example of the same. In this example, the shaft 14 located at the center of the semiconductive rubber roll is used.
Has a semi-cylindrical shape, and a semiconductive intermediate elastic layer 15 is formed in contact with the outer periphery thereof. Further, a surface layer 16 is formed on the outer periphery of the intermediate elastic layer.

As described above, an inner layer may be formed between the shaft body and the intermediate elastic body.

The method for producing the semiconductive rubber roll of the present invention is not particularly limited. As an example, a case of a three-layer structure like the semiconductive rubber roll shown in FIGS. 1 and 2 will be described.

The shaft is fixed in a roll mold, an epichlorohydrin-based rubber composition is put so as to cover the outer periphery of the shaft, shaped into a roll, and then heated to crosslink to form an intermediate elastic layer. . After formation, the surface of the intermediate elastic layer is polished as necessary for improving dimensional accuracy and adhesion, and a surface layer is formed thereon.

The method for forming the surface layer is not particularly limited. Usually, a resin or rubber constituting the surface layer is dissolved or dispersed in an organic solvent, water, or the like, and this solution or dispersion is applied to the surface of the intermediate elastic layer and dried. If necessary, a crosslinkable resin or a crosslinkable rubber containing a crosslinking agent or the like may be prepared, and a solution or dispersion thereof may be applied to the surface of the intermediate elastic layer, dried, and crosslinked to form a crosslinkable resin. . Examples of the coating method include brush coating, spray coating, immersion (dip), and the like, but a dip method is preferable from the viewpoint of production efficiency. Examples of the drying method include methods such as natural drying and heat drying. Among them, heat drying is preferable in order to increase the uniformity of the thickness of the surface layer. The crosslinking method is
There is no particular limitation, and a cross-linking method according to the properties of the resin or rubber used, the cross-linking agent, and the like may be used.

Alternatively, when the surface layer is a rubber layer, a laminate of an epichlorohydrin-based rubber composition, which is a raw material of the intermediate elastic layer, and a crosslinkable rubber composition, which is a raw material of the surface layer, is placed around an axis from an extruder. The intermediate elastic layer and the surface layer are simultaneously molded and cross-linked by extruding and heat-crosslinking the laminated body, and a treatment such as polishing the surface is performed as necessary. Simultaneous molding and simultaneous crosslinking of the intermediate elastic layer and the surface layer are preferred methods because the adhesion of the intermediate elastic layer and the surface layer is easy.

When the surface layer is a rubber layer, it is preferable to perform a surface treatment to reduce the friction coefficient of the surface layer. In order to perform the surface treatment, it is preferable to first appropriately polish the surface using an abrasive. Examples of the surface treatment method include ultraviolet irradiation, ozone exposure, application of a reactive silicone compound, and application of a reactive fluorine compound. By performing such a surface treatment, it is possible to prevent adverse effects due to adhesion of the rubber roll surface.

The semiconductive rubber roll according to the present invention is used in an image forming apparatus for developing an electrostatic latent image on a photoreceptor into a visible image by using a toner. It is suitable as such.

(Image Forming Apparatus) The image forming apparatus of the present invention has the semiconductive rubber roll of the present invention as at least one of rolls such as a charging roll, a developing roll and a transfer roll.

The structure and function of the image forming apparatus of the present invention are not particularly limited. For example, (1) a charging roll is brought into contact with a photoreceptor to charge the surface of the photoreceptor, and (2) exposure is performed by an exposure unit. Forming an electrostatic latent image on the surface of the photoconductor charged by (3), the developing roller coated with the toner abuts on the photoconductor, and the electrostatic latent image is developed into a visible image by the toner;
(4) The transfer roll is configured to function by transferring a toner to printing paper by applying a voltage.

FIG. 3 shows an example of such an image forming apparatus. In the image forming apparatus shown in FIG. 3, the photosensitive member 1 for forming an electrostatic latent image and the charging roll 10 are arranged so as to be in contact with each other, and a voltage is applied from a power source through a shaft of the charging roll. Thereby, the surface of the photoconductor is charged. Exposure is performed by an exposure device 9 using a laser light source or the like, and an electrostatic latent image is formed on the surface of the charged photoconductor 1. The photoreceptor 1 is arranged so as to be in contact with the developing roll 2. In the developing step, the toner 4 is applied to the surface of the adjacent developing roll 2 by the supply roll 6. The developing blade 3 uniformly controls the thickness of the toner applied to the surface of the developing roll.
The toner uniformly and uniformly applied on the surface of the developing roll visualizes the electrostatic latent image formed on the surface of the photoconductor drum.

The toner image on the photoconductor is generated by applying a voltage having a polarity opposite to that of the toner to the transfer roll 11 via a shaft by a power source and generating an electric field. Transfer to the transfer material 13.

After the transfer step, the toner remaining on the photoreceptor surface may be removed by a cleaning device such as a cleaning blade. FIG. 3 shows a so-called cleanerless type image without such a cleaning device. A forming device is shown. Therefore, the toner remaining on the surface of the photosensitive drum comes into contact with the charging roll. In the cleanerless system, after passing through the charging process,
Due to the difference between the charged surface potential of the photoconductor and the developing bias, the toner is attracted to the developing device by electrostatic force and collected. That is, the residual toner is collected by the electrostatic force generated in the developing process, for example, after the charging process and before the transfer process is started. In addition, the shaft of the developing roll 2 is usually configured so that a bias voltage can be applied. The transfer material is, for example, paper or an OHP sheet.

[0067]

The present invention will be described more specifically with reference to examples and comparative examples. All solvents and monomers used were subjected to degassing and dehydration treatment before use. The method for evaluating the properties of the intermediate elastic layer rubber and the method for evaluating the roll properties employed in this example are shown below.

[Reduced viscosity (η _sp / C)] The reduced viscosity is obtained by dissolving 1 g of a polymer in 100 ml of toluene at 30 ° C.
Was measured using an Ostwald viscometer type 0A.

[Hardness] The hardness was measured according to JIS K6253.

[Volume resistivity] Volume resistivity (Ω ·
cm), a sheet having a thickness of 2 mm is prepared from each material, and the sheet is sandwiched between electrodes with a guide ring, and a DC 500
The measurement was performed at 23 ° C. and 50% RH at a voltage of V.

[Roll electric resistance] Roll electric resistance (Ω)
Is a 200 m rubber surface using a stainless steel shaft
m, a rubber thickness of 3 mm, a semiconductive rubber roll having a roll outer diameter of 18 mm, a 1000 g brass electrode having the same length as the rubber surface, and a 500 V voltage applied between the electrode and the shaft of the semiconductive rubber roll. Was measured by applying a DC voltage of

[Photoconductor contamination] Photoconductor contamination was measured by fixing a commercially available photoconductor (for Oki Data, OL600e) and contacting the semiconductive rubber roll with the photoconductor at a load of 500 g at 45 ° C and 80 ° C. The sample was left standing for 4 weeks in an environment of% RH for evaluation. The evaluation was performed in three stages, and in Tables 1 and 2,
Indicates that no contamination was observed after 4 weeks, Δ indicates that no contamination was observed after 2 weeks, but then streaks were observed on the photoreceptor, and x indicates that contamination was observed before 2 weeks. Represents that

[Durability, L / L Print Density] The prepared semiconductive rubber roll was used as a developing roll and attached to an electrophotographic printer (image forming apparatus) to print 5% under an environment of 23 ° C. and 50% RH. Continuous printing was performed using the pattern, and printing quality such as print density and printing unevenness was evaluated.
When the print quality deteriorated, the experiment was performed by replacing the used photoconductor and toner with normal products, and the cause was confirmed. Causes of the deterioration of print quality include scraping of the photoconductor and toner deterioration. Further, the abrasion of the photoreceptor was confirmed by surface observation with a microscope. Print quality and photoreceptor abrasion were both evaluated on a three-point scale.
O indicates that the printing quality is stable even when 30,000 characters are printed, and Δ indicates that the printing quality is deteriorated when printing 30,000 sheets, but that the printing quality is stable even after printing 20,000 sheets. X indicates that the print quality is deteriorated on the 20,000th sheet after printing 20,000 sheets. In Table 1, the photoreceptor abrasion
It means that there is no effect of photoreceptor shaving even after printing 10,000 sheets. △ indicates that the effect of photoreceptor shaving is observed when printing 30,000 sheets. Indicates that there is no effect due to the scraping of the image, and x indicates that the print quality is deteriorated on the 20,000th sheet due to the scraping of the photoreceptor.

Further, under an L / L environment of low temperature and low humidity (10
(C, 20% RH). The L / L print density was evaluated by measuring the “black solid portion” using a Macbeth reflection densitometer.は indicates that the print density was 1.3 or more, and x indicates that the print density was 1.
Indicates less than 3.

Reference Example 1 A sealed pressure-resistant glass bottle having an internal volume of 800 ml was replaced with nitrogen, and 180 g of toluene and 60 g of triisobutylaluminum were charged. After cooling the glass bottle by immersing it in ice water, 224.2 g of diethyl ether was added and stirred. Next, while cooling with ice water, 8.8 orthophosphoric acid is added.
9 g was added and further stirred. At this time, the internal pressure of the bottle was increased by the reaction between the organic aluminum and the orthophosphoric acid, so the pressure was released as needed. Next, 8.98 g of formate of 1,8-diaza-bicyclo (5,4,0) undecene-7 was added. The resulting reaction mixture was aged for 1 hour in a 60 ° C. hot water bath to obtain a catalyst solution.

Reference Example 2 Epichlorohydrin 25 was added to a 5-liter autoclave.
1.4 g, allyl glycidyl ether 31 g, ethylene oxide 22.11 g, and toluene 2907.12 g were added, and the content liquid was heated to 70 ° C. while stirring under a nitrogen atmosphere. The reaction was started by the addition.

Next, 145.49 g of ethylene oxide was added to toluene 33 at an equal rate over 5 hours from the catalyst addition.
A solution dissolved in 9.48 g was continuously added. At the same time, 5
Over time, 7 milliliters of the catalyst solution were added every 30 minutes. The reaction was completed 5 hours after the addition of the catalyst.

After completion of the reaction, 15 g of water was added and stirred,
Further, 4,4′-thiobis- (6-tert-butyl-
45 g of a 5% by weight toluene solution of 3-methylphenol)
Added and stirred. In order to remove the solvent, steam stripping was performed, the supernatant water was removed, and then vacuum drying was performed at 60 ° C. to obtain epichlorohydrin rubber A having a Mooney viscosity of 85.
36.5 g were obtained. The epichlorohydrin rubber A has epichlorohydrin units / allyl glycidyl ether units /
NMR analysis confirmed that the ethylene oxide unit was a terpolymer having a molar ratio of 40/4/56.

Reference Example 3 The amount of epichlorohydrin was 339.7 g, the amount of allyl glycidyl ether was 49.95 g, the amount of ethylene oxide was 8.53 g, and the amount of toluene was 3125.69 g.
Except that the temperature was raised to 60 ° C. under a nitrogen atmosphere, the amount of the catalyst solution obtained in Reference Example 1 was changed to 10 ml, and the toluene solution of ethylene oxide was changed to a solution in which 51.82 g of ethylene oxide was dissolved in 120.91 g of toluene. By treating in the same manner as in Reference Example 1, 434.2 g of epichlorohydrin rubber B having a Mooney viscosity of 80 and a molar ratio of epichlorohydrin units / allyl glycidyl ether units / ethylene oxide units of 67/8/25 was obtained.

Reference Example 4 Epichlorohydrin 20 was added to a 5-liter autoclave.
Then, the inner solution was heated to 50 ° C. while stirring under a nitrogen atmosphere, and tin tetrachloride was added.
3 ml of a 0% by weight toluene solution was added to initiate polymerization. Further, every 30 minutes, the same tin tetrachloride solution was added in 3 ml portions for 10 hours to carry out a polymerization reaction. According to quantitative analysis of unreacted epichlorohydrin by gas chromatography analysis, the polymerization reaction rate was 81%. 61.5 g of a 20% by weight aqueous solution of sodium hydroxide was added to the obtained reaction mixture, and 4,4′-thiobis- (6-tert-butyl-3-methylphenol) was further added.
162 g of a 5% by weight toluene solution was added and stirred. In order to remove the solvent and unreacted monomers, steam stripping was performed, the supernatant water was removed, and then vacuum drying was performed at 60 ° C. to obtain a viscous low molecular weight epichlorohydrin having a reduced viscosity of 0.09. 1600 g of the combined a were obtained.

Reference Example 5 A low-molecular-weight epichlorohydrin polymer b66 was treated in the same manner as in Reference Example 4 except that the amount of epichlorohydrin was changed to 1930 g, and 70 g of ethylene oxide was added to the autoclave simultaneously with epichlorohydrin and toluene.
0 g was obtained. According to quantitative analysis of unreacted epichlorohydrin and unreacted ethylene oxide by gas chromatography, the polymerization reaction rate was 34%, the reduced viscosity was 0.06, and the N
According to MR analysis, the copolymer was a copolymer having a molar ratio of epichlorohydrin unit / ethylene oxide unit of 80/20.

Examples 1 to 7 and Comparative Examples 1 to 6 The rubber composition as the intermediate elastic layer material was prepared by kneading with the composition shown in Table 1 using a roll. In addition, the compounding materials not described above are as follows. Acrylonitrile-butadiene copolymer rubber: Nippon Zeon, Nipol 1052J, Nippon Zeon Ethylene-propylene-diene rubber: Mitsui Petrochemical Industries, EPT3042E, Liquid acrylonitrile-butadiene copolymer rubber: Nippon Zeon, Nipol1312, paraffin oil: Idemitsu Kosan, Diana Process PW-90, Carbon Black: Ketjen Black, Ketjen Black EC

The rubber composition of the material for the intermediate elastic layer was formed into a sheet and crosslinked at 155 ° C. for 30 minutes to form a sheet having a thickness of 2 mm.
Was obtained. Table 1 shows the results obtained by measuring the hardness and the specific volume resistivity as the rubber properties of the intermediate elastic layer using each of the obtained crosslinked rubber sheets.

The semiconductive roll was manufactured by laminating an intermediate elastic layer on a shaft and further laminating a surface layer as follows.

The intermediate elastic layer is made of stainless steel, has a total length of 263 mm, and has a length of 227 mm.
mm, a cylindrical solid body having an outer diameter of 10 mm is placed in a roll mold as a shaft, a rubber composition is put therein, and shaped into a roll around the shaft, and then heated to crosslink. went. After the cross-linking molding, the surface of the obtained rubber roll was polished with an abrasive, and polished by changing the grindstone until the 10-point average roughness described in JIS B0601 became 10 μm or less.

The surface layer was formed by the following methods (1) to (4).

(1) 80 parts by weight of an aqueous dispersion (solid content: 20% by weight) of a crosslinkable polyurethane resin composition (Superflex 126, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and 20 parts by weight of tin oxide were placed in a ball mill pot, and The roll on which the intermediate elastic layer was formed was immersed in the dispersion, dried, and dried.
A heat treatment was performed at 10 ° C. for 10 minutes to form a surface layer of a crosslinked polyurethane resin having a thickness of 50 μm. In Tables 1 and 2, “urethane” is written in the column of surface layer material, indicating that the surface layer of the urethane resin is provided.

(2) Except that a methanol solution (solid content: 20% by weight) of N-methoxymethylated nylon (Toresin EF-30T, manufactured by Teikoku Chemical Industries) was used instead of the aqueous dispersion of the crosslinkable polyurethane resin composition, The same treatment as in 1) was performed to form a surface layer having a thickness of 50 μm. In Table 1, "Nylon" in the column of the surface layer material indicates that the nylon resin surface layer is provided.

(3) A fluororesin (Lumiflon LF-601) is used in place of the aqueous dispersion of the crosslinkable polyurethane resin composition.
C, manufactured by Asahi Glass) Toluene / Xylene (50/50% by weight)
Ratio) The same treatment as in (1) was conducted except that a solution (solid content: 20% by weight) was used to form a surface layer having a thickness of 50 μm. In Table 1, "fluorine" is written in the column of surface layer material, indicating that the surface layer of this fluororesin was provided.

(4) 5 parts by weight of zinc oxide, 0.5 parts by weight of stearic acid, 50 parts by weight of tin oxide, 0.5 parts by weight of sulfur, 0.5 parts by weight of sulfur, and 100 parts by weight of acrylonitrile-butadiene copolymer rubber (Nipol 1052J) 1.5 parts by weight of thiuram disulfide was added and kneaded with a roll to obtain an acrylonitrile-butadiene copolymer rubber composition. This acrylonitrile-butadiene copolymer rubber composition was provided with a rubber composition layer on the outer peripheral surface of the intermediate elastic layer of a roll having the intermediate elastic layer formed thereon using an extruder. 16
After crosslinking by heating at 0 ° C. for 30 minutes, the surface was polished to a thickness of 500 μm. Further, a surface treatment by ultraviolet irradiation was performed to prevent sticking. Ultraviolet irradiation was performed by rotating a processing roll around an ultraviolet lamp having a lamp output of 80 W / cm and a rated power of 4000 W for 3 minutes. In Table 1, "NBR" is shown in the column of surface layer material.
Means that a surface layer of the crosslinked acrylonitrile-butadiene copolymer rubber was provided.

A sheet having a thickness of 2 mm was prepared under the same material and cross-linking conditions as the surface layer, and the volume resistivity (Ω · cm) was determined as the material of the surface layer. Roll characteristics include measuring the thickness of the intermediate elastic layer, surface layer thickness, roll hardness, roll electrical resistance, L / L print density, photoconductor contamination, durability (photoconductor shaving), durability (print quality), and roll change. Table 1 shows the results of the evaluation.

[0092]

[Table 1]

As shown in Table 1, in each of Examples 1 to 7, the intermediate elastic layer has a hardness of 30 or less, the hardness of the roll provided with the surface layer is 40 or less, and the electric resistance of the roll shows an appropriate resistance value. . In the durability test as a developing roll, there is no contamination of the photoreceptor, and the durability in the continuous printing test is excellent. Also, good images were obtained in a printing test under low temperature and low humidity (L / L).

In Comparative Example 1, although no plasticizer or the like was used in the intermediate elastic layer, the effect of ultraviolet irradiation was small and contamination of the photoreceptor occurred. Further, since the roll hardness is high, photoreceptor scraping and toner deterioration occur, resulting in poor durability.

In Comparative Example 2, by using liquid acrylonitrile-butadiene copolymer rubber for the intermediate elastic layer,
Although the roll hardness is lowered and the photoreceptor is not abraded, the durability is poor due to the photoreceptor contamination and toner adhesion since no surface layer is provided. In addition, the electric resistance of the roll increases and L /
The L print density decreases.

In Comparative Example 3, since the surface layer was provided, there was no contamination of the photoreceptor, but since the roll hardness was high, photoreceptor abrasion and toner deterioration occurred, resulting in poor durability.

In Comparative Example 4, since the liquid acrylonitrile-butadiene copolymer rubber was used for the intermediate elastic layer, the roll hardness was low and the photoreceptor was not shaved. However, the compatibility between epichlorohydrin rubber and the liquid acrylonitrile-butadiene copolymer rubber was poor. Although there is no contamination of the photoreceptor, liquid acrylonitrile-butadiene copolymer rubber is released from the intermediate elastic layer, and the electrical resistance of the roll increases in continuous printing, resulting in poor printing quality. Further, the compression set is poor, and the image becomes uneven.

In Comparative Example 5, since the acrylonitrile-butadiene copolymer rubber and the liquid acrylonitrile-butadiene copolymer rubber used in the intermediate elastic layer have good compatibility, there is no abrasion of the photosensitive member and no deterioration of the toner. However, since acrylonitrile-butadiene copolymer rubber is used, the electric resistance of the roll is high, the print density is low, and the print quality in durability evaluation is slightly inferior. In addition, the L / L print density is reduced.

In Comparative Example 6, although the hardness was low and the photoreceptor was not abraded or the toner deteriorated, a large amount of paraffin oil was used for the intermediate elastic layer, so the oil was released by continuous printing, the electric resistance of the roll increased, and The print quality is degraded due to the peeling. Further, photoreceptor contamination also occurs when left for a long period of time.

Examples 8 and 9 In Examples 8 and 9, semiconductive rolls were manufactured in the same manner as in the other examples except that the conductive material shown in Table 2 was provided as an inner layer between the shaft and the intermediate elastic layer. Each characteristic was measured and evaluated in the same manner as in Examples 1 to 7. Table 2 shows the results.

From a comparison between Examples 8 and 9, it is understood that the roll characteristics of this semiconductive roll can be adjusted by changing the inner layer. Also, the roll hardness is low, there is no contamination of the photoreceptor even when used for a long time, the printing quality is not deteriorated, and the durability is excellent. The acrylonitrile-butadiene copolymer rubber used in Example 9 was manufactured by Nippon Zeon, Nipo.
l DN223.

[0102]

[Table 2]

[0103]

The semiconductive rubber roll of the present invention is free from contamination of the photoreceptor, has low environmental dependence, has low hardness, has excellent compression distortion resistance and durability, and has a developing roll, a charging roll, and a transfer roller of an image forming apparatus. Useful as a roll.

Further, the image forming apparatus using the semiconductive rubber roll as a component has few troubles and troubles caused by the semiconductive rubber roll, and can form a stable image.

(Aspect) As an aspect of the present invention, (1)
Epichlorohydrin rubber composition containing (A) a shaft, (B) (a) a rubber component having epichlorohydrin rubber as an essential component, (b) a low molecular weight epichlorohydrin polymer, and (c) a crosslinking agent in order from the central axis. (C) a multilayer semiconductive rubber roll having at least three surface layers, (2) an epichlorohydrin rubber obtained by copolymerizing an alkylene oxide, epichlorohydrin, and an unsaturated epoxide. The roll according to (1), wherein the alkylene oxide is ethylene oxide and propylene oxide in a molar ratio of 10/90 to 90/10, preferably 15/85 to 85/15, more preferably 20/80
(2) The roll according to (2), wherein the amount of epichlorohydrin unit in the epichlorohydrin rubber is 30 to 100 mol%, preferably 35 to 90 mol%, more preferably 40 to 20/80. The roll according to any one of (1) to (3), which is 80 mol%, (5)
The amount of unsaturated epoxide units in the epichlorohydrin rubber is 1 to 15 mol%, preferably 2 to 12 mol%,
More preferably, it is 2.5 to 10 mol% (1) to
The roll according to any one of (4) and (6), wherein the epichlorohydrin rubber has a Mooney viscosity at 100 ° C. of 2
The roll according to any one of (1) to (5), which is a roll of any of (1) to (5), wherein the rubber component is an epichlorohydrin rubber 50 to 200, preferably 40 to 150, more preferably 50 to 100; 100% by weight, preferably 60 to
90% by weight, more preferably 70 to 85% by weight, and 0 to 50% by weight of other rubber, preferably 10 to 40% by weight, more preferably 15 to 30% by weight (1).
The roll according to any one of (1) to (6), (8), (b) the low molecular weight epichlorohydrin polymer is a copolymer obtained by copolymerizing an alkylene oxide, epichlorohydrin, and an unsaturated epoxide (1). The roll according to any one of (1) to (7), (9) (b) the low molecular weight epichlorohydrin polymer has an alkylene oxide unit amount of 0 to 70 mol%, preferably 5 to 65 mol%, and more preferably 10 to 60 mol%, epichlorohydrin unit amount is 30 to 100 mol%, preferably 35 to 95 mol%, more preferably 40 to 90 mol%, and unsaturated epoxide unit amount is 0 to 20 mol%, preferably 1 to 15 mol. %, More preferably 2.5 to 10 mol%, (10) (b) the low molecular weight epichlorohydrin polymer is at room temperature (2%). In to 30 ° C.) is of a liquid state (8) or (9), wherein the roll (1
1) (b) the low molecular weight epichlorohydrin polymer has a molecular weight of 1,000 to 10,000, preferably 1500 to 80;
(12) The roll according to any one of (8) to (10), which is a roll of (8) to (10), more preferably 2000 to 6000.
(B) the roll according to any one of (8) to (11), wherein the low molecular weight epichlorohydrin polymer has a Mooney viscosity of 1 or less; (13) (b) a toluene solution of the low molecular weight epichlorohydrin polymer. Reduced viscosity (η _sp
/ C) is from 0.01 to 0.5, preferably from 0.02 to 0.5.
(4) The roll according to any one of (8) to (12), more preferably 0.03 to 0.3, wherein the epichlorohydrin-based rubber composition is (100 parts by weight based on epichlorohydrin-based rubber) b) 10 to 150 parts by weight of a low molecular weight epichlorohydrin polymer,
Preferably 20 to 120 parts by weight, more preferably 30 to 120 parts by weight
100 parts by weight, 100 parts by weight of (a) rubber component, 0.1 to 10 parts by weight, preferably 0.2 to 10 parts by weight of crosslinking agent (c)
(1) a roll according to any one of (1) to (13), wherein the roll hardness (Duro-A) is 40 or less; The roll according to any one of (1) to (14), which is preferably 35 or less, more preferably 30 or less, (1)
6) The thickness of the intermediate elastic layer is 50 μm or more, preferably 1 μm.
00 μm or more, more preferably 200 μm or more, 30 m
m or less, preferably 20 mm or less, more preferably 15 mm or less.
(17) The roll according to any one of (1) to (15), wherein the volume specific resistance of the intermediate elastic layer is 10 ⁵ or less.
〜１０10 ¹² Ω · cm, preferably 10 ⁶ 〜１０10 ¹¹ Ω · c
m, more preferably 10 ⁷ to 10 ¹¹ Ω · cm, the roll according to any one of (1) to (16), (18).
An image forming apparatus including the roll according to any one of (1) to (17) as a component is exemplified.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a semiconductive rubber roll of the present invention.

FIG. 2 is an axial sectional view showing an example of a semiconductive rubber roll of the present invention.

FIG. 3 is a cross-sectional view illustrating an example of the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor 2 Developing roll 3 Developing blade 4 Toner 5 Developing container 6 Supply roll 7 Fixing roll 8 Pressure roll 9 Exposure device 10 Charging roll 11 Transfer roll 12 Stirring bar 13 Transfer material 14 Shaft 15 Intermediate elastic layer 16 Surface layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16C 13/00 F16C 13/00 E G03G 15/08 501 G03G 15/08 501D 15/16 103 15/16 103 // B29K 19: 00

Claims (2)

[Claims] 1. An axial body (A), and (B) in order from a central axis.
(A) a rubber component containing epichlorohydrin rubber as an essential component; (b) an intermediate elastic layer formed by crosslinking an epichlorohydrin rubber composition containing a low molecular weight epichlorohydrin polymer and (c) a crosslinking agent; and (C) A multilayer semiconductive rubber roll having at least three surface layers. 2. An image forming apparatus comprising the semiconductive rubber roll according to claim 1.