WO1999047823A1

WO1999047823A1 - Rubber roller having medium electric resistance and electrophotographic device

Info

Publication number: WO1999047823A1
Application number: PCT/JP1999/001382
Authority: WO
Inventors: Takeshi Ooishi; Kouichi Nishimura
Original assignee: Nippon Zeon Co., Ltd.
Priority date: 1998-03-19
Filing date: 1999-03-19
Publication date: 1999-09-23
Also published as: JP3726862B2; JPH11272043A

Abstract

A rubber roller having a medium electric resistance (having a volume resistivity of 10?6 to 1012¿ Φ.cm) which comprises a core body (A), an elastic layer (B) prepared by curing an epichlorohydrin-based rubber composition comprising a rubber component (a) comprising an epichlorohydrin-based rubber, a low molecular weight epichlorohydrin-based polymer (b) and a crosslinking agent (c), and a surface layer (C), wherein (A), (B) and (C) are arranged in that order from the center axis of the roller, and an electrophotographic device using the same.

Description

,

Description Medium resistance rubber mouth and electrophotographic equipment

The present invention relates to a rubber roll used in an electrophotographic apparatus such as an electrophotographic printer and an electrophotographic apparatus having the same. More specifically, the present invention relates to a rubber roll having a low hardness on the roll surface and a stable compression set. The present invention relates to a medium-resistance rubber roll excellent in durability and durability, and an electrophotographic apparatus having the same. Technology background

In an electrophotographic printer, the outer peripheral surface of a photosensitive drum is uniformly charged, and then an image is formed on the outer peripheral surface of the photosensitive drum by exposure to an electrostatic latent image, and the electrostatic latent image is formed using a toner. It has a mechanism for printing by developing and transferring the developed image to printing paper.

Conventionally, in the process of charging a photosensitive drum, charging has generally been performed by corona discharge. However, corona discharge has problems such as high cost and generation of harmful substances such as ozone. 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 photosensitive drum, and a charge is directly applied to the photosensitive drum to charge the surface of the photosensitive drum. In the transfer step, a method that does not use corona discharge has been proposed, in which a voltage is applied using a transfer roll to generate an electric field, and toner is transferred from a photosensitive drum to printing paper or the like for transfer. On the other hand, in the method using a non-magnetic one-component toner, the photosensitive drum and the developing roll are arranged so as to be in contact with each other, and the toner conveyed by the developing roll is moved between the developing roll and the developing blade. It is charged by friction. The charged toner moves from the developing roll to the photosensitive drum by the electric field generated between the developing roll and the photosensitive drum, and the latent image is developed.

An electrophotographic apparatus using such a structure in which a photosensitive drum and a roll are in contact with each other. In this method, a roll having a structure in which a rubber layer is formed on the surface of a core is used as a roll. A voltage must be applied between these rubber rolls and the photosensitive drum to generate an electric field. Therefore, rubber roll that has an electrical resistivity of the medium resistance region (medium res i st ivi ty range ), i.e. volume resistivity is required to be ^{^{1 0 6 ~ 1 0 1 2}} Ω ♦ cm.

As the medium resistance roll, generally, a roll obtained by dispersing a conductive filler such as carbon black, carbon fiber, or metal powder in resin or rubber and adjusting the electric resistance value is used. However, with such a roll, it is difficult to uniformly disperse the conductive filler, and the electrical resistance varies depending on the location, and the volume specific resistance value is 10 ^fi to 1 ◦ It is very difficult to adjust to the medium resistance region of ¹² Ω · cm. Therefore, the volume resistivity of itself has been proposed to use the E Pikuroruhi Doringomu a ^{^{1 0 7 ~ 1 0 1 1}} Ω. Cm. Rubber having such a volume resistivity does not require the addition of a conductive filler, and the unevenness of the electrical resistance due to uneven dispersion of the conductive filler occurs. Absent. However, epichlorohydrin rubber has a problem that the toner adheres to the surface and is easily stained due to its high adhesiveness on the surface.

A roll in which a non-adhesive coating layer made of a fluororesin composition or the like containing a conductive filler or the like is formed outside the epichlorohydrin rubber layer to prevent toner adhesion has also been proposed (JP-A-6-266620). No. 6, etc.). However, there was a problem that the durability of continuous printing was not sufficient, such as the photosensitive drum being worn or the toner being deteriorated, because the hardness of the roll surface was not sufficiently low.

Further, in order to reduce the hardness of the medium-resistance rubber roll, a method has been proposed in which a liquid unsaturated rubber such as liquid acrylonitrile-butadiene rubber, liquid polybutadiene, and liquid chloroprene is added (Japanese Patent Application Laid-Open No. Hei 9-1991). Publication No. 160354). However, there was a problem that the compatibility between the epichlorohydrin rubber and the liquid unsaturated rubber was not sufficient, and the compression set was poor. Disclosure of the invention

An object of the present invention is to prevent toner from adhering, to reduce environmental dependency, to improve durability and ₀ An object of the present invention is to provide a low-hardness medium resistance rubber roll having excellent compression distortion resistance. More specifically, an object of the present invention is to provide an electrophotographic apparatus for developing an electrostatic latent image on a photosensitive drum into a visible image by using a toner, and a developer port arranged in contact with the photosensitive drum. It is an object of the present invention to provide a medium-resistance rubber roll that can be suitably used as a roll, a charging roll, a transfer roll, and the like.

The present inventors have conducted intensive studies and found that a composition containing a core (A), an epichlorohydrin rubber (a) and a low molecular weight epichlorohydrin polymer (b) was bridged. A rubber roll having at least a three-layer structure with a certain elastic layer (B) and surface layer (C) can be adjusted to an appropriate electric resistance without using a conductive filler, etc., and the surface layer (C) can be used practically. It has been found that the roll has an appropriate elasticity even when a resin layer having a thickness that can be withstood is used. This medium-resistance rubber roll does not wear or contaminate the photosensitive drum. In addition, the toner hardly deteriorates and the durability is excellent. The present invention has been completed based on these findings.

Thus, according to the present invention, in order from the center, the core (A), the rubber component (a) having epichlorohydrin as an essential component, the low molecular weight epichlorohydrin polymer (b), and the crosslinking agent (c) The present invention provides an elastic layer (B) formed by cross-linking a contained epichlorohydrin rubber composition, and a medium-resistance rubber mouth having at least three surface layers (C). Further, an electrophotographic apparatus having the rubber roll is provided. BEST MODE FOR CARRYING OUT THE INVENTION

Core body (A)

The central part of the medium resistance rubber roll of the present invention is a core (A). The core (A) used in the present invention is not particularly limited as long as it is used as a core of a medium-resistance rubber roll, but is usually made of a conductive and rigid material. Things. As a conductive and rigid material, metals such as stainless steel and copper are preferably used for the core of a medium resistance rubber roll.

The core body (A) may have a cavity inside or may not have a cavity. The size and shape may be determined according to the purpose of use. The core (A) is shown in Fig. 1 and Fig. 2. Thus, it is preferable that the shape is a perfect cylinder. Adhesion between the core (A) and the layer laminated thereon, generally between the outer peripheral surface of the core and the layer laminated on the outer peripheral surface becomes uniform, and the nozzle is brought into contact with the photosensitive drum. This is because the pressure of the contact portion in the case of contact becomes uniform. However, the shape of the core is not particularly limited as long as the adhesiveness between the core and the layer to be laminated or the pressure at the contact portion with the photosensitive drum is within an allowable range. For example, by using a cylindrical core having the largest outer diameter at the center in the axial direction and the smaller outer diameter at both ends, the deflection of the core is reduced, and the contact portion with the photosensitive drum at the center in the axial direction is used. It is also possible to use a material whose pressure is smaller than that at both ends. It is preferable that the outer peripheral surface of the core body has a large surface roughness in order to improve the adhesion with the layer laminated on the outer peripheral surface.

Electric resistance adjustment layer

An electric resistance adjusting layer made of a conductive material may be provided on the outer peripheral surface of the core (A) as necessary. When an electric resistance adjusting layer is provided, it is possible to adjust the magnitude of the electric resistance of the roll by changing its thickness.

The conductive material used as the material of the electric resistance adjusting layer is not particularly limited, and conductive resin, conductive rubber, or a conductive filler such as carbon black, carbon fiber, metal powder, or the like is dispersed in the resin or rubber. Examples thereof include compositions prepared to have medium resistance.

Elastic layer (B)

In the medium resistance rubber roll of the present invention, the elastic layer (B) is formed on the outer peripheral surface of the core (A) or on the outer peripheral surface of the electric resistance adjusting layer formed on the outer peripheral surface of the core (A). This elastic layer (B) is formed by a crosslinked product of an epichlorohydrin rubber composition containing a rubber component (a) containing epichlorohydrin rubber as an essential component, a low molecular weight epichlorohydrin polymer (b) and a cross-linking agent (c). It is configured.

The rubber component (a) used in the present invention is a rubber containing epichlorohydrin rubber as an essential component, and may be a combination of other rubbers.

Epichlorohydrin rubber is a copolymer rubber obtained by copolymerizing epichlorohydrin with a homopolymer rubber or by mixing epichlorohydrin with an alkylene oxide and / or an unsaturated epoxide. _{c As the} alkylene oxide, for example, saturated alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide and isobutylene oxide; epifluorohydrin; Halogen-substituted saturated alkylene oxides such as lomethinoleethylene oxide; and the like, and each can be used alone or in combination of two or more. Of these, ethylene oxide and propylene oxide are preferred in view of availability and the like. When ethylene oxide and propylene oxide are used in combination, the ratio of the two (ethylene oxide / propylene oxide) is a molar ratio, preferably 10/90 to 90/10, more preferably 15/8. 5 to 85 Z15, particularly preferably 20/80 to 80/20.

Unsaturated epoxides include, for example, butadiene monooxide, 1,2-epoxy 5-hexene, 1,2-epoxy 17-octene, and other unsaturated epoxides / alkylene oxades; Glycidyl ethers such as glycidyl ether: glycidyl esters such as glycidyl methacrylate and glycidyl acrylate; Of these, aryl glycidyl ether is preferred. By copolymerizing the unsaturated epoxide, cross-linking with a sulfur cross-linking agent or an organic peroxide becomes possible, and pollution control and metal corrosion resistance are improved.

The amount of epichlorohydrin units in the epichlorohydrin gum is preferably from 30 to 100 mol ⁰ /. More preferably, 35 to 90 moles ⁰ /. More preferably, it is 40 to 80 monoles%. If the amount of the epichlorohydrin unit in the epichloronohydrin rubber is too large, the volume resistivity increases, and if it is too small, the hygroscopicity increases.

The amount of alkylene oxide units in the epichlorohydrin rubber is preferably from 0 to 70 mol ⁰ /. , More preferably from 10 to 65 mol%, particularly preferably from 20 to 60 mol%. If the amount of the alkylene oxide unit in the epichlorohydrin rubber is too large, it may not be used depending on the environment because the hygroscopicity becomes high or the volume-dependent resistance value becomes environment-dependent.

The amount of unsaturated epoxide units in the epichlorohydrin rubber is preferably from 0 to 15 mol ⁰ /. More preferably, 1 to 12 mol ⁰ /. Particularly preferably, it is 2 to 10 mol ^0/0 . If the amount of unsaturated epoxide units in _c- epiclorhydrin rubber is too large, low hardness It is difficult to obtain a crosslinked product. If the amount of unsaturated epoxide units is too small, it may not bridge.

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

The method for producing the epichlorohydrin rubber is not particularly limited. For example, it can be produced by a known solution polymerization method using an organoaluminum compound catalyst described in Japanese Patent Publication No. 56-511171.

In the rubber component (a) used for the production of the elastic layer (B), the rubber which can be used in combination with the epichlorohydrin rubber is not particularly limited, but preferred are an acrylonitrile butadiene copolymer rubber and hydrogenated hydrogen thereof. Additives, acrylonitrile copolymers rubbers and their hydrogenated products, atari lonitrile butadiene monoisoprene copolymer rubbers and their hydrogenated products, styrene butadiene copolymer rubbers and their hydrogenated products Products, ethylene propylene-gen copolymer rubber, chloroprene rubber, acrylic rubber, fluoro rubber, urethane rubber and the like. Ratio of Epikuroruhi Dori Ngomu and other rubber in the rubber component (a), generally, Epikuroruhi drill Ngomu 5 0-1 0 0 by weight ⁰ /. , Preferably 6 0-9 0% by weight, particularly preferably 7 0-8 5 weight ⁰ /. , Other rubber 0 ~ 50 weight ⁰ /. Preferably 10-40 weight ⁰ /. Particularly preferably, it is in the range of 15 to 30% by weight. If the amount of the other rubber is too large, the compatibility with the low molecular weight epichlorohydrin polymer (b) is deteriorated, and if the amount is too small, the effect of adding the optional rubber cannot be obtained.

The low molecular weight epichlorohydrin polymer (b) used in the present invention is a polymer containing an epichlorohydrin monomer unit. The low molecular weight epichlorohydrin polymer (b) may contain a monomer unit copolymerizable with epichlorohydrin. Examples of monomers copolymerizable with epichlorohydrin include alkylene oxides and unsaturated epoxides. As the alkylene oxide / unsaturated epoxide, those described as monomers of the epichlorohydrin rubber contained in the rubber component (a) are used.

Epiclorhydrin monomer unit in low molecular weight epichlorohydrin polymer (b) _n

The amount is preferably from 30 to 100 mol ⁰ /. More preferably, 35 to 100 mol ⁰ /. Particularly preferably 40 to 100 mol ⁰ /. It is. As the amount of epichlorohydrin monomer increases, the volume resistivity of the elastic layer increases, and as the amount decreases, the production of low molecular weight epichlorohydrin polymer (b) becomes more difficult. Arukirenokishi degrees is good Mashiku 0-7 0 mole ^_0/0, more preferably 0-6 5 mol%, particularly preferably from 0 to 6 0 mol ⁰ /. It is. As the number of alkylene oxide units decreases, the volume resistivity of the low molecular weight epichlorohydrin polymer (b) increases, and as the number increases, the production becomes more difficult. The amount of unsaturated epoxide units is preferably from 0 to 20 mol. /. More preferably, 0 to 15 mol%, particularly preferably 0 to 10 mol ⁰ /. It is. If the unsaturated epoxide unit content is too small, the low molecular weight epichlorohydrin polymer (b) will easily bleed from the crosslinked product of the epichlorohydrin rubber composition when crosslinked with a sulfur crosslinker or an organic peroxide. Become. On the other hand, if the amount of the unsaturated epoxide unit is too large, it is difficult to produce the low molecular weight epichlorohydrin polymer (b).

The low molecular weight epichlorohydrin polymer (b) is in a liquid state at normal temperature (20 to 30 ° C.), and preferably has a molecular weight of 1,000 to 100,000. It is preferably from 1,500 to 8,000, and particularly preferably from 2,000 to 6,000. In addition, the Mooney viscosity of the low molecular weight epichlorohydrin polymer is preferably 1 or less, and it is often impossible to measure it because it is too small. The reduced viscosity (NOC) of the low molecular weight epichlorohydrin polymer (b) in a toluene solution is preferably from 0.01 to 0.5, more preferably from 0.02 to 0.4, and particularly preferably from 0.02 to 0.4. It is preferably from 0.3 to 0.3. If r? _{S |} , / C is too large, the hardness of the rubber composition after crosslinking is too high, and if ηS _| , ZC is too small, the low molecular weight epichlorohydrin polymer (b) is obtained from the rubber composition after crosslinking. May bleed.

The method for producing the low molecular weight epichlorohydrin polymer (b) is not particularly limited. For example, a known solution weight using a catalyst such as stannic chloride, an organic aluminum / water complex, or a boron fluoride / ether complex. It can be manufactured legally.

Examples of the crosslinking agent (c) include a sulfur crosslinking agent, an organic peroxide, mercapto triazines, and thiopereas. Examples of sulfur crosslinking agents include sulfur and thiurams such as morpholine disulfide and tetramethylthiuram disulfide. ₀

Any sulfur donor can be mentioned. Organic peroxides include ketone peroxides, peroxyesters, disilver oxides, and alkyl peroxides, and when these organic peroxides are used, compression set resistance is reduced. Good crosslinked products are obtained. Examples of thiopereas include thiopereas, dibutyl thiopereas, and triethyl thiopereas.

The epichlorohydrin rubber composition used in the present invention contains a rubber component (a) containing epichlorohydrin rubber, a low molecular weight epichlorohydrin polymer (b), and a crosslinking agent (c).

The amount of the low molecular weight epichlorohydrin polymer (b) is preferably from 10 to 150 parts by weight, more preferably from 200 to 100 parts by weight of the epichlorohydrin rubber in the rubber component (a). To 120 parts by weight, particularly preferably 30 to 100 parts by weight. When the amount of the low molecular weight epichlorohydrin polymer (b) is too small, the hardness of the epichlorin rubber composition after crosslinking is too high. If the amount is too large, the low molecular weight epichlorohydrin polymer (b) will bleed from the crosslinked product of the epichlorin rubber composition or the viscosity will be low, making it difficult to prepare the rubber composition such as kneading.

The amount of the crosslinking agent (c) is preferably 0.1 to 100 parts by weight of the rubber component (a).

: 10 to 10 parts by weight, more preferably 0.2 to 7 parts by weight, particularly preferably 0.3 to 5 parts by weight.

If necessary, ordinary rubber compounding agents such as a crosslinking accelerator, a reinforcing agent, a filler, and an antioxidant can be appropriately mixed with the epichlorohydrin rubber composition.

The epichlorohydrin rubber composition can be obtained by mixing the materials to be compounded using a conventional kneading machine such as a mouth-to-wall Banbury mixer. Crosslinking of the epichlorohydrin rubber composition can be carried out by heating to 100 to 250 ° C. using an ordinary 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, and the hardness (Duro-A) is preferably 40 or less, more preferably 35 or less, and particularly preferably 30 or less. A crosslinked product is easily obtained. The epichlorohydrin rubber composition used in the present invention has low viscosity and dimensional stability It is suitable for extrusion molding and injection molding because of its excellent properties.

Crosslinked product of Epikuroruhi drill Ngomu composition for forming the elastic layer in the present invention is typically a volume resistivity of cross-linked product ^{^{1 0 5 ~ 1 0 1 2}} Ω cm, preferably ^{1 0 6 ~:. L 0} 1 ^{1 Ω} · cm, Yori preferably 1 0 ^7-1 0 ^1. '0 111.

The thickness of the elastic layer is not particularly limited, and the electrical resistance of the roll can be changed by changing the layer thickness. The layer thickness is preferably 50 μII! ~ 20 mm, more preferably 1Ο Ομπ! 11 O mm, particularly preferably 200 μιη〜5 mm. If the layer thickness is too thin, the electric resistance of the roll becomes too small, and the durability of the elastic layer may become a problem. The electric resistance of the roll becomes too high.

Surface layer (C)

On the outer peripheral surface of the elastic layer (B), a resin layer or a rubber layer is formed as the surface layer (B) for the purpose of preventing adverse effects due to the stickiness of the roll surface. As the resin layer or the rubber layer, a resin layer or a rubber layer having an electric resistance in a medium resistance region is preferable. Further, a crosslinked resin layer or a crosslinked rubber layer may be formed as necessary.

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

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, and if it has a hydrophilic functional group, a dispersion used for forming the surface layer is prepared using water. It becomes easier.

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

Among NIPPON resins that can be used as the resin constituting the resin layer, N-methoxymethylated nylon is preferable. N-methoxymethylated nylon is obtained by methoxymethylating the amide group of 6-nylon. _1Q

Since the solubility in alcohol is improved by increasing the meth- oxylation ratio of the compound, it becomes easy to prepare a solution used for forming the surface layer using alcohol. When a resin layer is used, the thickness of the surface layer is preferably 5 to 300 // m, more preferably 7 to 200 μπι, and still more preferably 10 to 150 μm. If the layer thickness is too small, the durability against abrasion decreases, and if the layer thickness is too large, the coating is liable to crack.

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

When a rubber layer is used as the surface layer, unlike a resin, the problem of cracking hardly occurs due to its high flexibility. Therefore, the thickness of the surface layer is not particularly limited.

Volume resistivity of the surface layer in order to reduce variations in electrical resistance, preferably 1 0 ⁵ to 1 0 ^{1 2} 0 '. 01, more preferably ^{^{1 0 5 5 ~:. L}} OQ 'c nu more preferably 1 0 ⁶ -1 0'. Ω · cm. Depending on the type of resin or rubber that forms the surface layer, conductive fillers such as carbon black such as acetylene black; conductive oxides such as tin oxide and zinc oxide; and conductivity-imparting agents such as surfactants may be used. It is preferable to adjust the volume specific resistance value by adding.

In addition, from the viewpoint of preventing contamination of the photosensitive drum and suppressing bleeding, the resin or rubber constituting the surface layer is provided with a compounding agent that causes bleeding, such as a plasticizer or a plasticizer. It is preferable not to use a softener or the like.

Medium resistance rubber roll

The medium-resistance rubber roll of the present invention comprises a core (A), a rubber component ( _a ) containing epichlorohydrin rubber as an essential component, a low molecular weight epichlorohydrin polymer (b), and a crosslinking agent (c) in this order from the central axis. It is a multilayer having at least three elastic layers (B) and a surface layer (C) formed by crosslinking the contained epichlorohydrin rubber composition. As a specific example, the medium resistance rubber roll shown in FIGS. 1 and 2 will be described. Figure 1 D. Cross-sectional view perpendicular to the axis showing an example of the medium resistance rubber roll of the present invention. FIG. 2 is an axial cross-sectional view showing an example of the same. In this example, the core body 14 present at the center of the medium-resistance rubber roll has a perfect cylindrical shape, and the 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 elastic layer 15.

Also, as described above, although not shown in FIGS. 1 and 2, an electric resistance adjusting layer may be formed between the core 14 and the elastic layer 15.

The method for producing the medium resistance rubber roll of the present invention is not particularly limited. An example of manufacturing a three-layer medium resistance rubber roll such as the medium resistance rubber roll shown in FIGS. 1 and 2 will be described.

The elastic layer (B) is formed by fixing the core body (A) in a roll mold, adding an epichlorohydrin rubber composition so as to cover the elastic layer forming surface on the outer periphery of the core body, and shaping into a roll shape. It is formed by heating and crosslinking.

After the formation of the elastic layer (B), the surface of the elastic layer (B) is polished, and then the surface layer (C) is formed on the surface of the elastic layer (B) as required for improving dimensional accuracy and adhesion. The method of forming the surface layer (C) is not particularly limited. The surface layer (C) is usually prepared by dissolving or dispersing a resin or rubber and a crosslinking agent in an organic solvent, water, or the like, applying this solution or dispersion to the surface of the elastic layer, drying, and then heating and crosslinking. Let it be formed.

For example, the surface layer of the polyurethane resin is prepared by allowing the polyurethane resin itself to act as an emulsifier, or by applying an aqueous polyurethane resin dispersion prepared using another emulsifier to the surface of the hydrophilic layer, It may be formed by drying the water. A cross-linking agent may be dispersed in this dispersion liquid, and after the moisture is dried, the cross-linking may be performed by heating. If the surface layer is formed by this method, environmental pollution is small because no organic solvent is used, and the elution of the binder from the elastic layer can be suppressed without swelling the elastic layer containing rubber.

Examples of the coating method include brush coating, spray spraying, and dipping, but a dip method is preferred 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 cross-linking method is not particularly limited, 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. 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.

Alternatively, when the surface layer is a crosslinked rubber layer, a laminate of an epichlorohydrin rubber composition as a raw material for the elastic layer and a crosslinkable rubber composition as a raw material for the surface layer is extruded around an axis from an extruder. The elastic layer and the surface layer may be simultaneously molded and cross-linked by heat-crosslinking the laminate as it is, and the surface may be polished if necessary. Simultaneous molding and simultaneous crosslinking of the elastic layer and the surface layer are preferred methods because the elastic layer and the surface layer are easily bonded.

The medium-resistance rubber roll of the present invention is an electrophotographic apparatus that develops an electrostatic latent image on a photosensitive drum into a visible image with toner, such as a developing roll, a charging roll or a transfer roll disposed in contact with the photosensitive drum. It is very suitable.

Electrophotographic equipment

The electrophotographic apparatus of the present invention has at least one medium resistance rubber roll of the present invention out 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) the charging roll contacts the photosensitive drum to charge the surface of the photosensitive drum, and (2) the photosensitive drum is exposed by the exposure unit. An electrostatic latent image is formed on the surface of the charged photosensitive drum, and (3) the developing roll comes into contact with the photosensitive drum, and the electrostatic latent image is developed into a visible image by the toner carried by the developing roll. (4) It is configured and functions to transfer voltage to printing paper by applying a voltage using a transfer roll.

FIG. 3 shows an example of such an electrophotographic apparatus. In the electrophotographic apparatus shown in FIG. 3, the photosensitive drum 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 the core of the charging roll. Thus, the surface of the photosensitive drum is charged. The surface of the photosensitive drum 1 that has been exposed and charged by the exposure device 9 using a laser light source, etc. An electrostatic latent image is formed on the surface. The photosensitive drum 1 is arranged so as to be in contact with the developing roll 2 as well. In the developing step, the toner 4 is applied to the surface of the adjacent developing roll 2 by the supply roll 6. The thickness of the toner applied to the surface of the developing roll is uniformly controlled by the developing blade 3. The toner uniformly and uniformly applied on the surface of the developing roll visualizes the electrostatic latent image formed on the photosensitive drum surface.

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

After the transfer process, the toner remaining on the surface of the photosensitive drum may be removed by a cleaning device such as a cleaning blade, but FIG. 1 shows a so-called cleanerless system without such a cleaning device. An electrophotographic apparatus is shown. Therefore, the toner remaining on the surface of the photosensitive drum comes into contact with the charging roll. In the cleanerless method, after passing through a charging process, toner is attracted to a developing device by electrostatic force and collected by a difference between a charged surface potential of the photosensitive drum and a developing bias. That is, after the charging step is completed and before the transfer step is started, for example, the residual toner is recovered by electrostatic force generated in the developing step. The core 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.

Hereinafter, 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. The method for evaluating rubber characteristics and the method for evaluating roll characteristics employed in this example are shown below.

[Reduced viscosity (η _SP / C)]

The reduced viscosity was measured by dissolving 1 g of the polymer in 100 ml of toluene in a constant temperature water bath at 30 ° C. using an Ostold viscometer type 0A.

[Hardness]

Hardness was measured according to JISK 6253.

[Volume resistivity]

The specific volume resistance (Ω · cm) was determined by preparing a 2 mm thick sheet of each material, sandwiching it between electrodes with guide rings, and applying a voltage of 500 V DC at 23 ° C and 50 ° C. % Measured at RH.

[Roll electrical resistance]

The electrical resistance (Ω) of the roll is determined by using a stainless steel core to create a medium-resistance rubber roll with a rubber surface length of 20 O mm, a rubber thickness of 3 mm, and a roll outer diameter of 18 xn m. A 100 g brass electrode of the same length as above was placed, and a DC voltage of 500 V was applied between the electrode and the core of the medium-resistance rubber roll for measurement.

[Stain control of photosensitive drum]

To control the contamination of the photosensitive drum, a commercially available photosensitive drum (made by Oki Data, for OL600E) was fixed, and a medium-resistance rubber roll was brought into contact with the photosensitive drum so that the load became 500 g. At 45 ° C. and 80% RH for 4 weeks. The evaluation was performed in three stages. In the tables showing the results of the examples and the like, 表し indicates that no contamination was observed after 4 weeks, and △ indicates that no contamination was observed after 2 weeks. X indicates that streaks are observed on the photosensitive drum, and X indicates that contamination is observed before 2 weeks have elapsed.

[Suppression of wear of photosensitive drum, suppression of deterioration of print quality, L / L printing density] Attach the produced medium-resistance rubber roll to the electrophotographic printer as an electrophotographic device at 23 ° C as a developing roll. In a 50% RH environment, continuous printing was performed in a pattern of 5% printing, and printing quality such as printing density and printing unevenness was evaluated. If the print quality was degraded, the photosensitive drum and toner used were replaced with normal ones, and an experiment was conducted to confirm the cause. The causes of print quality deterioration include wear of the photosensitive drum and deterioration of toner.

Furthermore, the wear of the photosensitive drum was confirmed by surface observation with a microscope.

Both the print quality deterioration control and the photosensitive drum wear control are evaluated on a three-point scale. In the tables showing the results of the examples, etc., the print quality deterioration suppressing properties are as follows: 〇 indicates that the print quality is stable even when 30,000 characters are printed, and Δ indicates that the print quality is reduced when 30,000 sheets are printed. However, the print quality is stable even after printing 20,000 sheets, and X indicates that the print quality deteriorates on 20,000 sheets after printing 20,000 sheets.

In the table, 摩耗 indicates that the photosensitive drum was worn even after 30,000 sheets were printed. △ indicates that there is no effect due to wear, and △ indicates that the effect due to the wear of the photosensitive drum is observed when 30,000 sheets are printed, but even if 20,000 sheets are printed, the effect due to the wear of the photosensitive drum occurs on 20,000 sheets. X indicates that 20,000 sheets have been printed, and a reduction in print quality due to wear of the photosensitive drum is observed on the 20,000th sheet.

In addition, the print density under the low temperature and low humidity LZL environment (10 ° C, 20% RH) was also evaluated. Evaluation of LZL print density was performed by measuring “black solid portion” using a Macbeth reflection densitometer. 〇 indicates that the print density is 1.3 or more, and X indicates that the print density is less than 1.3.

Reference example 1

The inside of a sealed pressure-resistant glass bottle having a capacity of 800 milliliters 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 getyl ether was added and stirred. Then, 8.89 g of orthophosphoric acid was added while cooling with ice water, followed by further stirring. At this time, the internal pressure of the bottle increased due to the reaction between the organic aluminum and the orthophosphoric acid. Next, 8.98 g of the formate of 1,8 diazabicyclo (5,4,0) ndecene 7 were added. The resulting reaction mixture was aged for 1 hour in a hot water bath at 60 ° C to obtain a catalyst solution.

Reference example 2

5 Add 51.4 g of epiclone / rehydrin to an autorove of litnole, 31 g of arylene glycidyl ether, 22.1 g of ethylene oxide, and 2907.1 toluene 2 g was added, the content liquid was heated to 70 ° C. while stirring under a nitrogen atmosphere, and the reaction was started by adding 13 milliliters of the catalyst solution obtained in Reference Example 1.

Next, a solution prepared by dissolving 144.49 _g of ethylene oxide in 33.488 _g of toluene was added continuously at a constant rate over 5 hours from the catalyst addition. At the same time, 7 milliliters of the catalyst solution was added every 30 minutes for 5 hours. The reaction was completed within 5 hours from the catalyst addition.

After the completion of the reaction, 15 g of water was added and the mixture was stirred, and 4,4′-thiobis- (6-tert-butyl-3-methylphenol) 5 wt / ⁰ . 45 g of a toluene solution was added and stirred. In order to remove the solvent, perform steam stripping and remove the supernatant water. After removal, vacuum drying is performed at 60 ° C to obtain epichlorohydrin rubber A with a Mooney viscosity of 85.

46.5 g were obtained. Epichlorohydrin rubber A is composed of epichlorohydrin units Z arylglycidyl ether units / ethylene oxide units in a molar ratio of 40/4 /

It was confirmed by NMR analysis that the terpolymer was 56.

Reference example 3

The amount of epichloronohydrin to 339.7 g, the amount of arylglycidyl ether to 49.95 g, the amount of ethylene oxide to 8.53 g, and the amount of toluene to 312.5.69 g g, the temperature in a nitrogen atmosphere was raised to 60 ° C, the amount of the catalyst solution obtained in Reference Example 1 was changed to 10 milliliters, and the toluene solution of ethylene oxide was converted to ethylene oxide 51 The same treatment as in Reference Example 1 was repeated except that 8.2 g was dissolved in 120.9 g of toluene, except that Mooney viscosity was 80, epichlorohydrin unit / aryl glycidyl ether unit, and 7 ethylene oxide. 434.2 g of epichlorohydrin rubber B having a unit of 678 Z25 in molar ratio was obtained.

Reference example 4

In a 5-liter autoclave, add 200 g of epichronorehydrin and 857 g of toluene, raise the temperature of the inner solution to 50 ° C while stirring under a nitrogen atmosphere, and add tetrachloride. tin 3 0 wt ^_0/0 toluene solution was started 3 millimeter Li Tsu torr added polymerize. Further, every 30 minutes, the same tin tetrachloride solution was added in 3 milliliters over a period of 10 hours to carry out a polymerization reaction. Quantitative analysis of unreacted epichlorohydrin by gas chromatography showed that the polymerization reaction rate was 81%. . Hydroxide to the resulting reaction mixture sodium 2 0 weight ⁰ I solution 6 1 5 g was added for an additional 4, 4 'Chiobisu (6 -. T ert-butyl-3-methylphenol) 5 weight ⁰ /. Toluene solution (162 g) was added and stirred. In order to remove the solvent and unreacted monomers, steam stripping was performed. After removing the supernatant water, vacuum drying was performed at 60 ° C to obtain a viscous solution having a reduced viscosity of 0.09. A low-molecular-weight epichlorohydrin polymer a1600 g was obtained. Reference example 5

Low-molecular-weight epichlorohydrin 600 g of polymer b was obtained. Moth Quantitative analysis of unreacted epichlorohydrin and unreacted ethylene oxide by chromatography showed a polymerization rate of 34%, a reduced viscosity of 0.06, and an NMR analysis showed that The copolymer was a copolymer having a molar ratio of xide units of 80Z20.

Examples 1 to 7, Comparative Example:! ~ 6

With the composition shown in Table 1, the mixture was kneaded with a roll to prepare a rubber composition as an elastic layer material. In addition, the compounding materials that are not described above are as follows. Atari lonitrile butadiene copolymer rubber: Nippon Zeon, Nipo 110

2 J,

Ethylene-propylene-gene rubber: Mitsui Petrochemical Co., Ltd., EP3042E, liquid athali-lonitrile butadiene copolymer rubber: Nippon Zeon, Nipo 11

3 1 2,

Paraffin oil: Idemitsu Kosan, Diana Process PW-90,

Carbon black: Ketjen black, Ketjen black E C

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

The medium-resistance rubber roll was manufactured by laminating an elastic layer on a core body and further laminating a surface layer as follows.

The elastic layer is made of stainless steel, the entire length of which is 2 63 mm, the length of the elastic layer forming section is 2 27 mm, and the outer diameter is 10 mm. The rubber composition was put therein, shaped into a roll around the core, and then heated to crosslink. After the cross-linking molding, the surface of the obtained rubber roll was polished using a grindstone, and the surface of the grindstone was polished until the 10-point average roughness Rz became 10 μm or less.

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

(1) Crosslinkable polyurethane resin composition (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., Superflex 126) Aqueous dispersion (solids concentration: 20 parts by weight) 80 parts by weight and tin oxide 20 parts by weight Part into a ball mill pot, disperse well, and a roll with an elastic layer formed on this dispersion Was immersed, dried, and then heat-treated at 150 ° C. for 10 minutes to form a 50 μm-thick crosslinked polyurethane resin surface layer. In Tables 1, 2 and 3, “PU” is written in the column of surface layer material, indicating that the surface layer of the urethane resin was provided.

(2) N-methoxymethylated nylon (Toresin EF-30T, manufactured by Teikoku Chemical Industries) methanol solution (solids concentration 20% by weight) was used instead of the aqueous dispersion of the crosslinkable polyurethane resin composition. Was treated in the same manner as in (1) to form a surface layer with a thickness of 50 μπι. In Table 1, “NY” is written in the column of the surface layer material, which indicates that the surface layer of the nip resin is provided.

(3) Instead of the aqueous dispersion of the crosslinkable polyurethane resin composition, a fluororesin (Lumiflon LF-601C, manufactured by Asahi Glass), toluene Z-xylene (50/50 weight / ₀ ratio) solution (solid fraction) (Concentration: 20% by weight), except that (1) was used to form a 50 // m thick surface layer. In Table 1, “F” is written in the column of surface layer material, indicating that the fluororesin surface layer was provided. '

(4) Acrylonitrile-butadiene copolymer rubber (Nipo 110 105 J, manufactured by Zeon Corporation) 5 parts by weight of zinc oxide and 0.5 parts by weight of stearic acid based on 100 parts by weight , 50 parts by weight of tin oxide, 0.5 parts by weight of sulfur, and 1.5 parts by weight of tetraethylthiuram disulphide are added and kneaded with a roll, and the acrylonitrile-butadiene copolymer rubber composition is added. I got Using the acrylonitrile-butadiene copolymer rubber composition, an extruder was used to provide a rubber composition layer on the outer peripheral surface of the viscous layer of a roll having a viscous layer formed thereon. After crosslinking by heating at 160 ° C. for 30 minutes, the surface layer was polished to a thickness of 500 μπι. In addition, surface treatment was performed by UV irradiation to prevent sticking. Ultraviolet irradiation was performed for 3 minutes by rotating the roll to be treated around an ultraviolet lamp with a lamp output of 80 WZ cm and a rated power of 4000 W. In Table 1, "NB" is written in the column of the surface layer material, indicating that the surface layer of the crosslinked acrylonitrile-rebutadiene copolymer rubber was provided.

A sheet with a thickness of 2 mm was prepared using the same material as the surface layer and under the same cross-linking conditions. The material properties of the surface layer were determined as volume resistivity (Ω · cm). The elastic layer thickness, surface layer thickness, roll surface hardness, roll electrical resistance, L / L print density, photosensitive drum contamination suppression, photosensitive drum Tables 1 and 2 show the results of measurement or evaluation of the ram abrasion control, print quality deterioration control, and roll change.

As shown in Table 1, in each of Examples 1 to 7, the elastic layer had a hardness of 30 or less in hardness, the surface of the roll provided with the surface layer had a hardness of 40 or less, and the electrical resistance of the roll was an appropriate resistance value. Is shown. There is no contamination of the photosensitive drum in the durability test as a developing roll, and the durability in the continuous printing test is excellent. Also, under low temperature and low humidity (LZL)

Claims

Good image was obtained in the printing test.Table 2

As shown in Table 2, in Comparative Example 1 having no surface layer, no plasticizer or the like was used for the elastic layer, but the effect of ultraviolet irradiation was small, and the photosensitive drum was contaminated. In addition, the hardness of the roll surface is high, resulting in abrasion of the photosensitive drum and deterioration of the toner. The printing quality is reduced, resulting in poor durability. In Comparative Example 2, by using liquid acrylonitrile-butadiene copolymer rubber for the elastic layer, the hardness of the roll surface was reduced and no abrasion of the photosensitive drum was observed. However, since no surface layer was provided, the printing quality deteriorated due to the photosensitive drum, contamination, and toner adhesion, and the durability was poor. Also, the electrical resistance of the roll increased, and the LZL print density decreased.

In Comparative Example 3, since the surface layer was provided, no contamination of the photosensitive drum was observed. However, since the hardness of the roll surface is high, there is a durability problem that the photosensitive drum is worn and the toner is deteriorated, and the printing quality is reduced.

In Comparative Example 4, since the liquid acrylonitrile-butadiene copolymer rubber was used for the elastic layer, the hardness of the roll surface was low, there was no wear on the photosensitive drum, and there was no contamination on the photosensitive drum. However, the epichlorohydrin rubber and the liquid acrylonitrile reloopagen copolymer rubber have poor compatibility, and the liquid acrylonitrile butadiene copolymer rubber is released from the elastic layer, and the electrical resistance of the roll increases during continuous printing, and printing is performed. Quality degrades. Also, the compression set is poor, and the image becomes uneven.

In Comparative Example 5, the acrylonitrile-butadiene copolymer rubber used for the elastic layer and the liquid acrylonitrile-butadiene copolymer rubber have good compatibility, so that there is no abrasion of the photosensitive drum and no deterioration of the toner. However, since acrylonitrile-butadiene copolymer rubber is used, the electrical resistance of the roll is high, the print density is low, and the suppression of print quality deterioration is somewhat inferior. Also, the LZL print density will be low.

In Comparative Example 6, the hardness of the roll was low, and there was no abrasion of the photosensitive drum and no deterioration of the toner. However, since a large amount of paraffin oil is used for the elastic layer, the oil is released by continuous printing, increasing the electrical resistance of the roll and deteriorating the printing quality due to peeling of the surface layer. In addition, contamination of the photosensitive drum is caused by leaving it for a long time. Examples 8, 9

In Examples 8 and 9, a medium-resistance rubber roll was manufactured in the same manner as in the other Examples except that the conductive material shown in Table 3 was provided between the core and the elastic layer as an electric resistance adjusting layer, and each characteristic was measured. And evaluated. Table 3 shows the results. The acrylonitrile-butadiene copolymer rubber used in Example 9 was Nipol DN 223 manufactured by Zeon Corporation. Table 3

From a comparison between Examples 8 and 9, it can be seen that the roll characteristics of this medium-resistance rubber roll can be adjusted by changing the electric resistance adjustment layer. In addition, the hardness of the roll surface is low, and there is no contamination of the photosensitive drum even when used for a long time, and the print quality is not deteriorated and the durability is excellent. Industrial applicability

The medium-resistance rubber roll of the present invention is free from contamination of the photosensitive drum, has low environmental dependency, has low hardness, has excellent compression distortion resistance and durability, and is used as a developing roll, a charging roll, a transfer roll, etc. of an electrophotographic apparatus. And useful.

In addition, the electrophotographic apparatus using the medium resistance rubber roll as a component has few troubles and troubles caused by the medium resistance rubber roll, and can perform stable printing.

The scope of the claims

I. In order from the central axis, a core (A), a rubber component (a) containing epichlorohydrin rubber as an essential component, a low molecular weight epichlorohydrin polymer (b), and a crosslinker (c) containing a crosslinker (c) A medium-resistance rubber roll having at least three layers of an elastic layer (B) formed by crosslinking a rubber composition and a surface layer (C).

2. The rubber mouth according to claim 1, wherein the rubber is a copolymer rubber obtained by copolymerizing epylene chlorohydrin rubber, epanol hexylene oxide, epichlororen hydrin and unsaturated epoxide.

3. The rubber according to claim 2, wherein the alkylene oxide is a combination of ethylene oxide and propylene oxide at a molar ratio of 10 to 90 to 90/10.

P-one.

4. The amount of the epichloronorethin units in the epichlorohydrin rubber is 30 to 100 mol. /. The rubber mouth according to any one of claims 1 to 3, wherein

5. Epiku Roruhi amount of unsaturated Epokishido units in Doringomu is, rubber roll according to any of from 1 to 1 to 5 mol ⁰ I in which the claims 1-4.

6. Epiclorhydrin rubber strength; The rubber mouth according to any one of claims 1 to 5, wherein the Mooney viscosity in C is 20 to 200.

7. rubber component (a) force; rubber port Lumpur according to any one of claims 1 to 6 claims is shall be contained Epiku Roruhi drill Ngomu 5 0-1 00 weight ⁰ do.

8. Low molecular weight epichlorohydrin polymer (b): a copolymer obtained by copolymerizing an alkylene oxide, an epichlorohydrin, and an unsaturated epoxide; The rubber mouth according to any one of the above.

9. Low molecular weight Epiku Roruhi drill down polymer (b) force;, alkylene oxide b de unit weight 0-70 mole ^_0/0, Epiku Roruhi Dorin unit weight 3 0-1 00 mole ⁰ /. 9. The rubber mouth according to claim 8, wherein the unsaturated epoxide unit amount is 0 to 20 mol%.

10. The rubber roll according to claim 8 or 9, wherein the low molecular weight epichlorohydrin polymer (b) is in a liquid state at 20 to 30 ° C.

II. The rubber mouth according to any one of claims 8 to 10, wherein the low molecular weight epichlorohydrin polymer (b) has a molecular weight of from 1,000 to 10,000.

12. The rubber roll according to any one of claims 8 to 11, wherein the low molecular weight epichlorohydrin polymer (b) has a viscosity of 1 or less.

1 3. The method according to any one of claims 8 to 12, wherein the reduced viscosity (77 sp / C) of the low molecular weight epichlorohydrin polymer (b) in a toluene solution is from 0.01 to 0.5. The rubber opening described.

1 4. The epichlorohydrin rubber composition contains 100 parts by weight of the rubber component (a), 100 to 150 parts by weight of the low molecular weight epichlorohydrin polymer (b), and 0.1% by weight of the crosslinking agent (c). The gomulonole according to any one of claims 1 to 13, which contains 1 to 10 parts by weight.

1 5. The rubber opening according to any one of claims 1 to 14, wherein the mouth hardness (Duro-A) is 40 or less.

1 6. The rubber mouth according to any one of claims 1 to 15, wherein the elastic layer has a thickness of 50 µm to 30 mm.

1 7. The volume resistivity of the弹性layer ^{^{1 0 5 ~ 1 0 1 2}} Ω. Any force ranging 1-1 6 according as cm, and rubber roll according to.

1 8. An electrophotographic apparatus containing the roll according to any one of claims 1 to 17 as a part.