JP2009108265A - Surface-treating liquid for conductive elastic layer, method of surface treatment of the same, and surface-treated conductive member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure satisfactory print quality over a long period by retaining electrical conductivity of a conductive member such as a conductive roller used for a conductive mechanism of an electrophotographic apparatus in an adequate range, effectively preventing deterioration of durability, and reducing the voltage dependence of electrical resistance and resistance unevenness. <P>SOLUTION: A surface-treating liquid comprises carbon nanotubes dispersed in a medium containing a polyol compound and an isocyanate compound and/or a reaction product of the polyol compound and isocyanate compound. A coating layer is formed by applying the surface-treating liquid to the outer surface of a conductive elastic layer formed using one or more elastic materials selected from the group consisting of rubber, resin and thermoplastic elastomers, and then thermally curing the coating. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface treatment liquid for a conductive elastic layer, a surface treatment method, and a surface-treated conductive member, and more particularly, to a conductive member such as a conductive roller used in a conductive mechanism of an electrophotographic apparatus. The deterioration of durability is prevented, the voltage dependency of the electrical resistance value and the resistance unevenness are reduced while obtaining appropriate conductivity, and a good print image quality can be obtained over a long period of time.

  In a conductive mechanism in an electrophotographic apparatus such as a printer, an electrophotographic copying machine, a facsimile apparatus, or an electrostatic recording apparatus, a charging roller for uniformly charging a photosensitive drum, a toner supply roller for conveying toner, Various conductive members are used as represented by conductive rollers such as a developing roller for adhering toner to the photoconductor and a transfer roller for transferring a toner image from the photoconductor to a sheet.

  Such a conductive roller is generally composed of a cylindrical cored bar and an elastic layer made of vulcanized rubber, resin, thermoplastic elastomer and the like laminated concentrically around the cored bar. Therefore, various performances such as conductivity, non-contamination, and dimensional stability are required depending on applications. In particular, when used for a long time, there is a problem of so-called durability deterioration, in which residual toner particles or chemicals added to the toner adhere to the surface of the conductive roller and the image deteriorates. Similarly, the conductive member is required to prevent this deterioration of durability.

  In order to prevent such deterioration of durability, conventionally, the surface of the conductive member such as an elastic layer is coated with an isocyanate compound or a polyurethane resin.

  On the other hand, in recent years, the use of carbon nanotubes has been studied in various fields, and carbon nanotube dispersions in which carbon nanotubes are uniformly dispersed in a solvent have been disclosed in JP-A-2003-300716 (Patent Document 1) and JP-A-2004-276232. (Patent Document 2), Japanese Patent Application Laid-Open No. 2007-63051 (Patent Document 3), and the like.

JP 2003-300716 A JP 2004-276232 A JP 2007-63051 A

Although the coating layer formed by coating the isocyanate compound or polyurethane resin as described above improves durability deterioration, since this kind of material generally has a high electric resistance, In order to adjust the electrical resistance value, a conductive agent such as carbon black or an ionic conductivity imparting agent must be blended. However, when carbon black is blended in the coating layer, the voltage dependency of the electrical resistance value is increased, and the conductive member is not uniformly charged, resulting in a problem of uneven printing. In addition, when an ionic conductivity imparting agent is blended, the conductive agent bleeds and the conductive member becomes sticky, and the photosensitive drum and the conductive member stick to each other when stored in contact with the photosensitive drum for a long time. The problem of lack of sex arises.
Moreover, none of the carbon nanotube dispersion liquids of Patent Documents 1 to 3 prevent durability deterioration of the conductive member, and do not have characteristics necessary as a coating layer for the conductive member.
Thus, there is a demand for a surface treatment of a conductive member that effectively prevents the deterioration of the durability of the conductive member, maintains the conductivity within an appropriate range, and is excellent in charging characteristics and use performance.

  The present invention has been made in view of the above problems, and keeps the conductivity of a conductive member such as a conductive roller used in a conductive mechanism of an electrophotographic apparatus within an appropriate range, effectively reducing durability. It is an object to reduce the voltage dependence of the electrical resistance value and the resistance unevenness while preventing it, and to obtain a good print image quality over a long period of time.

In order to solve the above problems, the present invention is a surface treatment liquid for performing a coating treatment on the surface of a conductive member,
There is provided a surface treatment liquid characterized in that carbon nanotubes are dispersed in a medium containing a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and the isocyanate compound.

  As a result of diligent research, the present inventors have found that a surface treatment liquid in which carbon nanotubes are dispersed in a medium containing a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and the isocyanate compound has appropriate conductivity. In addition, it has been found that a coating layer in which the voltage dependency of the electrical resistance value and the resistance unevenness are reduced while effectively preventing deterioration of durability can be formed on the surface of the conductive member. That is, since the surface treatment liquid for the conductive member of the present invention contains carbon nanotubes as a conductive agent, the problems of voltage dependence of electric resistance value and resistance unevenness caused when carbon black is mixed are greatly reduced. Thus, a coating layer imparted with appropriate conductivity can be formed without causing the stickiness that occurs when an ionic conductivity imparting agent is blended. And since the coating layer formed with this surface treatment liquid uses the polyurethane resin obtained by thermosetting a polyol compound and an isocyanate compound as a matrix resin, durability deterioration can also be prevented effectively.

The surface treatment liquid of the present invention contains, in addition to carbon nanotubes, a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and the isocyanate compound, and a solvent serving as a medium thereof as essential components.
Hereinafter, each component will be described in detail.

As the carbon nanotube, a single-walled carbon nanotube in which one layer of graphene sheets in which carbon atoms bonded in a honeycomb shape spread in a planar shape are formed in a cylindrical shape, and a multi-layer carbon nanotube in which two or more layers are concentrically stacked in a cylindrical shape And those in which they are coiled, it is preferable to use multi-walled carbon nanotubes. A single-layer structure and a multilayer structure may be mixed in the carbon nanotube.
A carbon material partially having a carbon nanotube structure can also be used. Furthermore, not only carbon nanotubes with holes on both sides, but also carbon nanohorns with closed carbon nanotubes, cup-shaped nanocarbon materials with holes on their heads, and the like can be used.

As the carbon nanotube, it is preferable to use a single-walled or multi-walled carbon nanotube having a diameter of 1 to 50 nm and a length of 0.01 to 50 μm.
In particular, it is preferable to use a multilayer structure having a diameter of 10 to 20 nm and a length of 0.1 to 10 μm. The aspect ratio is preferably 10 or more.
Carbon nanotubes of this size are easily dispersed uniformly in the surface treatment liquid, and the carbon nanotubes are easily in contact with each other, so that it is easy to form a coating layer having uniform conductivity.
Further, the carbon nanotubes may be subjected to a surface treatment by oxidation treatment in order to disperse in a medium mainly composed of water described later.

The carbon nanotubes are preferably contained in the surface treatment liquid of the present invention at a ratio of 0.1% by mass or more and 1.0% by mass or less. More preferably, it is 0.2 mass% or more and 0.8 mass% or less.
This is because the carbon nanotube content in the coating layer formed when the carbon nanotubes are less than 0.1% by mass in the surface treatment liquid is reduced, and sufficient conductivity cannot be imparted to the coating layer. If the amount exceeds 0.0 mass%, the carbon nanotubes are entangled in the surface treatment solution, and the carbon nanotubes tend to be hardened, which may cause non-uniform electrical resistance.

Moreover, it is preferable that the carbon nanotubes are contained in a ratio of 0.5% by mass or more and 5.0% by mass or less in the total solid content excluding the medium of the surface treatment liquid.
This is because when the total solid content is less than 0.5% by mass, the content of carbon nanotubes in the coating layer is small, and sufficient conductivity cannot be imparted to the coating layer. This is because the compounding amount of the nanotubes becomes excessive, the carbon nanotubes are entangled and tend to be hardened, and the electric resistance value may be uneven. More preferably, the carbon nanotubes in the total solid content are 1.0 mass% or more and 3.0 mass% or less.
As described above, since the carbon nanotube is extremely excellent in electrical conductivity, a desired electrical resistance value can be obtained with a small amount of blending, and the voltage dependence of the electrical resistance value and resistance unevenness can be reduced.

The surface treatment liquid contains a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and the isocyanate compound in a medium. These polyol compounds, isocyanate compounds and their reactants are dispersed and / or dissolved in the medium.
These polyol compounds and isocyanate compounds exist in a state in which they do not react with each other in the surface treatment liquid, in a partially reacted state, or in a state in which they are mixed.
When a polyurethane resin obtained by thermosetting a polyol compound and an isocyanate compound is used as a resin for forming a coating layer on the surface of a conductive member, the result is extremely excellent in paper passing durability.

The polyol compound is a polyvalent hydroxy compound and is a compound having at least two hydroxyl groups in one molecule. Examples of the polyvalent hydroxy compound include aliphatic hydrocarbon polyols, polyether polyols, polyester polyols, acrylic polyols, fluorine-containing polyols, epoxy polyols, polycarbonate polyols, and urethane polyols.
Of these, acrylic polyols and urethane polyols are preferably used.

Acrylic polyols include those obtained by copolymerizing a polymerizable monomer having one or more active hydrogens in one molecule and a monomer copolymerizable therewith. For example, (i) acrylic acid esters having active hydrogen such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxylbutyl acrylate: 2-hydroxyethyl methacrylate, 2-hydroxy methacrylate Methacrylic acid esters having active hydrogen such as propyl, 2-hydroxyl-methacrylic acid: acrylic acid monoester or methacrylic acid monoester of glycerin, acrylic acid monoester or trimethacrylic acid monoester of trimethylolpropane A single or a mixture selected from methacrylic acid and acrylic acid having polyvalent active hydrogen;
(Ii) Acrylic acid esters such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate: methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, methacryl A single or mixture selected from methacrylic acid esters such as n-butyl acid, isobutyl methacrylate, and n-hexyl methacrylate;
(Iii) Unsaturated carboxylic acids such as acrylic acid, methacrylic acid and itaconic acid, unsaturated amides such as acrylamide and N-methylol acrylamide: and polymerizable monomers such as styrene, vinyl toluene, vinyl acetate and acrylonitrile Examples thereof include acrylic polyol resins obtained by polymerization in the presence or absence of a mixture.

  Urethane polyols include those having a urethane bond in the polymer produced by the polyaddition reaction of an aromatic, aliphatic or alicyclic diisocyanate with an active hydrogen compound, and having a hydroxyl group at the polymer side chain or terminal. Can do.

The said polyol compound can be used individually or in mixture of 2 or more types.
The polyol compound used in the present invention preferably has a resin hydroxyl value of 10 to 300 mgKOH / g.

The isocyanate compound that reacts with the polyol compound to form a polyurethane resin can be regarded as a curing agent for the polyurethane resin when the polyol compound is a main component.
As the isocyanate compound, aliphatic and / or alicyclic diisocyanates or polyisocyanates (polyisocyanates) derived therefrom are preferably used.
Examples of the aliphatic and / or alicyclic diisocyanates include 2,4 monotolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, Hexamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 3,3′-dimethyl-4,4 ′ monobiphenylene diisocyanate, 3,3′-dimethoxy-4,4′- Biphenylene diisocyanate, 3,3′-dichloro-4,4′-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, isophorone diisocyanate It is below.
In addition, modified products such as isocyanurate bodies, burette bodies, adduct bodies, and allophanate bodies of isocyanate compounds are exemplified. An isocyanurate form of hexamethylene diisocyanate is preferably used because of its excellent surface treatment durability.

It is preferable that the isocyanate group of the isocyanate compound is blocked (masked). By blocking (masking) isocyanate groups, the reactivity of isocyanate compounds, which are difficult to control due to high reactivity, can be suppressed, the pot life can be extended, and the quality control of the surface treatment solution can be facilitated. Can do.
“Isocyanate group is blocked” means that the compound is in a state of reacting with a compound capable of reversibly reacting with the isocyanate group and the reactivity of the isocyanate group is inactivated. To do. Examples of blocking agents for blocking isocyanate groups include phenols, ε-caprolactams, β-diketones, oximes, etc., but the reason is that the balance between the quality stability of the treatment liquid and the degree of dissociation is excellent Β-diketones, oximes, and ε-caprolactams are preferred.

From the viewpoint of workability in the coating / curing step of the surface treatment liquid and uniform coating, the total amount of the polyol compound and the isocyanate compound is 15% by mass or more and 50% by mass or less, and further 20% by mass in the surface treatment liquid. It is preferable that it is 40 mass% or less.
Furthermore, the polyurethane resin obtained by thermally curing the polyol compound and the isocyanate compound is preferably 80% by mass or more and less than 99.9% by mass in the total solid content obtained by curing the surface treatment liquid. . More preferably, it is 92.0 mass% or more and 99.0 mass% or less.

  The solvent used as the medium may be any solvent that can be evaporated by heat treatment or the like, and can disperse the carbon nanotubes, and can disperse and / or dissolve the polyol compound and isocyanate compound. Water, alcohol Various liquids such as alcohols, glycols, glycol esters, esters and ketones can be used.

In particular, the medium is harmless to the human body and the environment, and since the volatilization of the organic solvent is suppressed as compared with the method using a large amount of the organic solvent, the medium does not affect the work environment or the global environment. It is preferable that the solvent is mainly composed of.
The “medium mainly composed of water” is a solvent having water as a main component, and refers to a medium in which the mass of water in the total mass of the solvent is 50% by mass or more and 100% by mass or less. Preferably it is 60 mass% or more, Furthermore, it is good that it is 80 mass% or more. As solvents other than water, esters, ketones, alcohols, glycols, glycol esters and the like may be mixed.

As described above, the surface treatment liquid of the present invention may contain carbon nanotubes, a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and an isocyanate compound, and a medium as essential components. From the viewpoint of easily dispersing the nanotubes uniformly in the surface treatment liquid, it is preferable that the nanotubes are prepared by the following procedures (1) to (3).
(1) A carbon nanotube dispersion is prepared by dispersing carbon nanotubes in a medium that does not contain a polyol compound, an isocyanate compound, and these reactants.
(2) Separately from (1), a liquid in which a polyol compound and an isocyanate compound are dispersed and / or dissolved in a medium is prepared. At this time, the polyol compound and the isocyanate compound may partially react to generate a reaction product.
(3) Then, (1) and (2) are mixed.
It is easier to uniformly disperse carbon nanotubes by blending carbon nanotubes in a medium that does not contain a polyol compound and an isocyanate compound as in (1) than in direct blending in a medium that contains a polyol compound and an isocyanate compound. There are advantages.

  In the above (1), as a method of dispersing the carbon nanotubes in the medium in advance, an optimal method can be selected according to the medium to be used, but the carbon nanotubes subjected to surface treatment such as oxidation treatment are used. Alternatively, a method of blending a surfactant with the medium can be used.

  In the method (2), the method for dispersing and / or dissolving the polyol compound and the isocyanate compound in the medium can be appropriately selected depending on the type of the medium used and the polyol compound and the isocyanate compound. For example, other functional groups having an affinity for the medium to be used may be introduced, or a surfactant such as a dispersant or a wetting agent may be added.

In particular, when an isocyanate compound is dispersed in a medium mainly composed of water, it is preferable to use an isocyanate compound into which a hydrophilic group has been introduced. Thus, by introducing a hydrophilic group, the isocyanate compound can be made water-soluble, and the isocyanate compound is dispersed or / and dissolved in a water-based medium that is harmless to the human body and the environment. Is possible.
Since the polyol compound contains a large number of hydroxyl groups that are hydrophilic groups, it is usually unnecessary to introduce a hydrophilic group when dispersed in a medium mainly composed of water.

The said hydrophilic group can be suitably introduce | transduced into an isocyanate compound in the range which does not impair the inhibitory effect of durability deterioration of an electroconductive member. Specifically, it may be introduced at a rate of 1 to 50% by mass, preferably 3 to 30% by mass. Thereby, it is possible to achieve both compatibility with water and an effect of suppressing deterioration of durability of the conductive member.
Examples of the hydrophilic group include polyethers, carboxylates, sulfonates, and the like. Particularly, ammonium salts of carboxylic acids are preferable because of excellent surface treatment solution stability.

  In addition to the above-described surface treatment liquid, the surface treatment liquid may be a conductive agent other than the carbon nanotube (for example, conductive carbon black, weakly conductive carbon black, etc.), the polyol, Resin components other than isocyanate compounds, lubricants and the like can also be blended. By blending a lubricant, the coefficient of friction can be lowered.

The surface treatment liquid for the conductive member is applied to various conductive members such as a conductive roller and a conductive belt mounted on the image forming apparatus, thereby preventing deterioration of durability and providing conductivity. It is possible to form a coating layer with little voltage dependence and resistance unevenness of the electrical resistance value.
The surface treatment liquid can be used for conductive members made of various materials, but is particularly preferably used for a conductive elastic layer of a conductive member formed using an elastic material.

  In view of this, the present invention provides a method in which the surface treatment liquid is applied to the outer surface of a conductive elastic layer formed using one or more elastic materials selected from the group consisting of rubber, resin, and thermoplastic elastomer, and then heated. There is provided a surface treatment method for a conductive elastic layer, characterized by performing a curing treatment to form a coating layer.

  According to the surface treatment method, since the processing is easy, it is possible to easily perform the durability deterioration preventing process on the conductive member. In particular, if the medium is mainly water, the working environment is remarkably improved, and it is extremely excellent in terms of global environmental conservation.

As a method for applying the surface treatment liquid to the surface of the conductive elastic layer, a conventionally known method such as dipping, roll coating, knife coating, spray coating or the like can be used.
The temperature of the heat curing treatment is 110 ° C. or higher and 200 ° C. or lower, preferably 120 ° C. or higher and 170 ° C. or lower, although it depends on the type of polyol compound or isocyanate compound. When the temperature is lower than 110 ° C., the polyol compound and the isocyanate compound are difficult to be cured, or when the blocked isocyanate compound is used, the blocking agent is difficult to dissociate. On the other hand, when the temperature is higher than 200 ° C., the conductive elastic layer may be deteriorated, which is not preferable.

  Although the time of the heat curing treatment depends on the temperature of the heat curing treatment, a time during which the curing is sufficiently performed and the conductive elastic layer does not deteriorate can be appropriately selected, and is 5 minutes to 120 minutes, preferably 10 minutes. It is good that it is 60 minutes or less.

The present invention further includes a conductive elastic layer formed using at least one elastic material selected from the group consisting of rubber, resin and thermoplastic elastomer, and a coating layer covering the surface of the conductive elastic layer. A conductive member comprising:
The coating layer provides a conductive member in which carbon nanotubes are dispersed in a polyurethane resin obtained by thermosetting a polyol compound and an isocyanate compound.

In the coating layer of the conductive member, carbon nanotubes are dispersed in a polyurethane resin obtained by a reaction between a polyol compound and an isocyanate compound, and conductivity is imparted by the carbon nanotubes. Therefore, in addition to being able to reduce the voltage dependency and resistance unevenness of the electrical resistance value that occurs when conductivity is imparted by carbon black, there is no occurrence of bleeding of the conductive agent as in the case of adding an ionic conductivity imparting agent. In addition, sticking between the conductive member and the photosensitive drum and deterioration of image quality are not caused. Therefore, the conductive member of the present invention can obtain good image quality over a long period of time by effectively preventing deterioration in durability and maintaining good and uniform charging characteristics and storage stability. Alternatively, it can be suitably used as a conductive roller such as a developing roller, a charging roller, or a transfer roller that is mounted on an image forming apparatus such as a color printer.
In addition, the coating layer of the said electroconductive member can also be formed by methods other than the surface treatment method mentioned above.

The coating layer preferably contains the carbon nanotubes in a proportion of 0.5 mass% to 5.0 mass%, preferably 1.0 mass% to 3.0 mass%.
In the conductive member, the thickness of the coating layer is 1 μm or more and 50 μm or less, preferably 5 μm or more and 30 μm or less. This range is because if the thickness is less than 1 μm, the durability deteriorates, and if it is more than 50 μm, cracks may occur.

  The conductive elastic layer of the conductive member serving as a base material on which the coating layer is formed is formed using one or more elastic materials of rubber, resin, and thermoplastic elastomer, and has conductivity. Although it will not be limited if it comprises, For example, it can produce using a component as enumerated below.

As a raw material component of the elastic material constituting the conductive elastic layer,
This rubber is a brominated rubber of ethylene-propylene-diene rubber (EPDM), butyl rubber (IIR), halogenated butyl rubber (X-IIR), acrylonitrile butadiene rubber (NBR), acrylic rubber, and a copolymer of isobutylene and p-methylstyrene. Brominated isobutylene-p-methylstyrene copolymer (BIMS), fluorine rubber, silicone rubber, chloroprene rubber (CR), natural rubber (NR), butadiene rubber (BR), styrene butadiene rubber (SBR), isoprene rubber (IR) ), Rubbers such as ethylene propylene rubber, hydrogenated nitrile rubber (HNBR) or chlorosulfonated polyethylene rubber;
Thermoplastic elastomers such as styrene thermoplastic elastomer, polyester thermoplastic elastomer, amide thermoplastic elastomer, olefin thermoplastic elastomer;
Resins such as polyethylene, polypropylene, ethylene ethyl acrylate resin, ethylene vinyl acetate resin, ethylene-methacrylic acid resin, ionomer resin or olefin resin such as chlorinated polyethylene;
These can be used alone or in combination of two or more.
In particular, rubber such as EPDM and NBR, styrene-based thermoplastic elastomer because it has both elasticity and flexibility like rubber and good moldability and recyclability like resin, and excellent mechanical properties and processing finish. And an elastic material formed from a thermoplastic elastomer composition containing an olefin resin.

Further, in order to impart conductivity to the conductive elastic layer, an ionic conductivity imparting agent such as a metal salt; a metal oxide such as carbon black, tin oxide, titanium oxide, graphite, or conductive silica, copper, Conductive fillers such as metal powders such as nickel and aluminum can be used.
As the ionic conductivity-imparting agent, in particular, an ethylene oxide-propylene oxide copolymer and / or an ethylene oxide-propylene oxide-allyl glycidyl ether copolymer containing a metal salt can be preferably used.

In addition to the conductive filler, a filler such as calcium carbonate, silica, clay, talc, barium sulfate, diatomaceous earth, or the like may be blended in order to improve mechanical strength.
Also, fatty acids such as stearic acid and lauric acid, cottonseed oil and tall oil are used as long as they do not cause liberation of additives from the surface of the conductive elastic layer, transfer to contact materials such as bleed, blooming and photoconductor contamination. Softeners such as asphalt substances and paraffin wax may be blended. Thereby, the hardness and softness | flexibility of a conductive elastic layer can be adjusted moderately.
Furthermore, various additives such as a vulcanizing agent, a vulcanization accelerator, a foaming agent, an antiaging agent, and a plasticizer can be blended as necessary. As the vulcanizing agent, for example, sulfur, organic-containing sulfur compound, peroxide, resin cross-linking agent and the like can be used.

  The conductive elastic layer of the conductive roller can be prepared by a conventional method, for example, a component that constitutes an elastic material such as a rubber component, a thermoplastic elastomer component, a resin component, etc., in which an additive such as a conductive agent is blended as necessary. Is put into a rubber kneading device such as an open roll, a Banbury mixer, a kneader, etc. in the required blending and blending order, kneaded to obtain a kneaded product, and then preformed into a tube shape with a single-screw extruder. After vulcanizing (crosslinking), after inserting the metal core and polishing the surface, it is possible to use a method such as cutting to a required dimension to form a conductive elastic layer. Vulcanization (crosslinking) of the kneaded product can be performed using a technique such as dynamic crosslinking as necessary.

  The thickness of the conductive elastic layer is 1 mm or more and 10 mm or less, preferably 1.5 mm or more and 6 mm or less. The above range is used because it is difficult to obtain sufficient chargeability when the thickness is less than 1 mm. On the other hand, if it is thicker than 10 mm, insufficient charging tends to occur, and the member is too large to be suitable for reduction in size and weight.

The electrical resistance value of the conductive member including the coating layer and the conductive elastic layer may be 10 ⁴ Ω or more and 10 ¹⁰ Ω or less, preferably 10 ⁵ Ω or more and 10 ⁸ Ω or less. The reason for this is that it is difficult to obtain a conductive member smaller than 10 ⁴ Ω. On the other hand, if it is larger than 10 ¹⁰ Ω, there is a problem that the efficiency of transfer, charging, toner supply, etc. is lowered, making it unsuitable for practical use. The electrical resistance value of the conductive member is measured by the method described in the examples in which the conductive member is in a roll shape.

  As described above, since the carbon nanotube is dispersed in the medium containing the polyol compound and the isocyanate compound, the surface treatment liquid of the present invention maintains the conductivity of the conductive member within an appropriate range and effectively reduces the durability. In addition, it is possible to reduce the voltage dependency of the electrical resistance value and the resistance unevenness, and to form a coating layer on the conductive member that can obtain a good print image quality over a long period of time. In addition, the coating layer formed from the surface treatment liquid of the present invention does not cause bleeding of the conductive agent as in the case of using an ionic conductivity imparting agent. Does not cause sticking or degradation of image quality.

  The conductive member of the present invention is obtained by thermally curing a conductive elastic layer formed using one or more elastic materials selected from the group consisting of rubber, resin and thermoplastic elastomer, and a polyol compound and an isocyanate compound. And a coating layer in which carbon nanotubes are dispersed in the obtained polyurethane resin. Therefore, the coating layer does not interfere with the conductivity of the conductive elastic layer, and the electrical resistance value of the conductive member is kept within an appropriate range, effectively reducing the voltage dependency of the electrical resistance value and resistance unevenness. Deterioration can be prevented. In addition, since there is no bleed of the conductive agent from the coating layer, it is excellent in storage stability and a good printed image can be obtained over a long period of time.

  Moreover, according to the surface treatment method for a conductive member of the present invention, durability deterioration can be easily improved in a conductive member such as a conductive roller. In particular, when the surface treatment liquid uses a medium mainly composed of water, volatilization of the organic solvent is suppressed compared to the conventional method using a large amount of organic solvent, so that the working environment is remarkably improved. Is also excellent.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a conductive roller 10 according to an embodiment of the present invention.
The conductive roller 10 is attached by press-fitting a cylindrical cored bar (shaft) 12 into a hollow portion of a cylindrical conductive elastic layer 11 formed of a conductive thermoplastic elastomer composition. A roller portion 14 having a coating layer 13 on the surface is formed.
The coating layer 13 is formed by uniformly dispersing carbon nanotubes in a polyurethane resin obtained by thermosetting a polyol compound and an isocyanate compound.

The coating layer 13 is applied to the surface of the conductive elastic layer 11 with a surface treatment liquid in which carbon nanotubes are dispersed in a medium containing a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and the isocyanate compound. Then, it is formed by performing a heat curing process.
The polyol compound and the isocyanate compound, and the reaction product of the polyol compound and the isocyanate compound are present in a dispersed and / or dissolved state in the medium.

First, a method for preparing the surface treatment liquid for forming the coating layer 13 will be described.
[Preparation of surface treatment solution]
As the surface treatment liquid of this embodiment, a carbon nanotube dispersion liquid (A) in which carbon nanotubes are dispersed in water and a liquid (B) in which a polyol compound and an isocyanate compound are dispersed and / or dissolved in water are individually prepared. Then, it is obtained by mixing both.

As the carbon nanotube dispersion liquid (A), a carbon nanotube having a diameter of 10 to 20 nm and a length of 0.1 to 10 μm is dispersed in water at a concentration of 3 to 5% by mass. The carbon nanotubes in the carbon nanotube dispersion are uniformly dispersed in water by adding a surfactant to the medium, or by using carbon nanotubes that have been oxidized and have a hydrophilic surface. Yes.
The oxidation treatment of the carbon nanotubes can be performed by performing plasma treatment or the like on the powdered carbon nanotubes.

The carbon nanotubes used in the present invention may be those available on the market or those produced by any method known in the art.
Carbon nanotube production methods include arc discharge method, laser evaporation method, vapor phase growth method, carbon dioxide catalytic hydrogen reduction method, CVD method, carbon monoxide reaction with iron catalyst at high temperature and high pressure, and growth in the gas phase HiPco method is used. Especially, it is preferable to manufacture by a vapor phase growth method and a CVD method.

A liquid in which the polyol compound and isocyanate compound (B) are dispersed and / or dissolved in water is prepared as follows.
Acrylic polyols and urethane polyols are used as polyol compounds, and isocyanate compounds in which hydrophilic groups such as polyethers, carboxylates and sulfonates are introduced into aliphatic and / or alicyclic diisocyanates as isocyanate compounds, These are prepared by dispersing and / or dissolving in water. Specifically, for example, an isocyanurate form of hexamethylene diisocyanate into which an ammonium salt of carboxylic acid is introduced is used.

  Furthermore, the isocyanate group of the polyisocyanate compound may be blocked with oximes, β-diketones or ε-caprolactams. Thus, the surface treatment liquid using the polyisocyanate compound in which the isocyanate group is blocked is extremely excellent in storage stability because the reactivity of the isocyanate group is suppressed.

Next, the surface treatment liquid of this embodiment is prepared by mixing the previously prepared carbon nanotube dispersion liquid and the liquid in which the polyol compound and the isocyanate compound are dispersed.
As long as the effects of the present invention are not hindered, conductive carbon black, a lubricant, and the like are mixed in the surface treatment liquid as desired. When the lubricant is blended, the blending amount is selected from the range of 5 to 20% by mass in the surface treatment liquid.
The surface treatment liquid thus obtained contains carbon nanotubes in a proportion of 0.3% by mass to 1.2% by mass.
In the present embodiment, the surface treatment liquid is prepared in the blending order. However, the present invention is not limited to the blending order as long as the carbon nanotubes, the polypole compound, and the isocyanate compound are uniformly present in the medium.

[Description of conductive elastic layer]
Below, the electroconductive elastic layer 11 used as the base material which forms the coating layer 13 is demonstrated.
In addition, the composition of the electroconductive elastic layer 11 demonstrated by this embodiment is an example, and is not limited to the thing of the following structure.
The conductive thermoplastic elastomer composition for forming the conductive elastic layer is a thermoplastic elastomer composition in which EPDM is dynamically cross-linked by a resin cross-linking agent and dispersed in a mixture of an olefin resin and a styrene thermoplastic elastomer. A base polymer component (A), and an EO-PO-AGE copolymer containing an ion conductive conductive agent containing a metal salt composed of a metal cation and an anion having a fluoro group and a sulfonyl group. (B) A component, (C) component which consists of ethylene-acrylic acid ester-maleic anhydride copolymer, and (D) component which consists of a polyester-type thermoplastic elastomer are included. Here, the EO-PO-AGE copolymer in the component (B) made of the ion conductive conductive agent may be dynamically cross-linked.

In the conductive elastomer composition, the mixing ratio of the styrene thermoplastic elastomer and the olefin resin is 30 to 50 parts by mass of the olefin resin with respect to 100 parts by mass of the styrene thermoplastic elastomer. EPDM as a crosslinkable rubber is blended in an amount of 100 to 400 parts by mass with respect to 100 parts by mass of the mixture of the styrene thermoplastic elastomer and the olefin resin. The compounding amount of the resin crosslinking agent is 5 to 15 parts by mass with respect to 100 parts by mass of EPDM.
The component (B) composed of the ion conductive conductive agent is contained in the conductive thermoplastic elastomer composition at a volume fraction of 20 to 40%. The compounding amount of the ion conductive conductive agent (B) is 3 to 25 parts by mass with respect to 100 parts by mass of the base polymer (A). The said metal salt is mix | blended in the ratio of 10-25 mass parts, when the whole (B) component of an ion conductive electrically conductive agent shall be 100 mass parts. The blending amount of the ethylene-acrylic acid ester-maleic anhydride copolymer (C) is 3 to 30 parts by mass with respect to 100 parts by mass of the component (B) of the ion conductive conductive agent, and 100 parts by mass of the component (A) of the base polymer. 0.5 to 5 parts by mass with respect to part, and 10 to 40 parts by mass with respect to 100 parts by mass of the polyester-based thermoplastic elastomer (D) component.

  The conductive thermoplastic elastomer composition forming the conductive elastic layer 11 contains a softener, calcium carbonate and carbon black, and optionally a foaming agent, in addition to the components (A) to (D).

The conductive thermoplastic elastomer composition is produced by the following method.
First, EPDM is pelletized in advance, and the pellet-shaped EPDM, styrene thermoplastic elastomer, olefin resin, cross-linking agent, and softening agent are kneaded at a temperature of 200 ° C., and heat as component (A) of the base polymer is obtained. A pellet of the plastic elastomer composition is prepared.

  (A) component pellet made of the thermoplastic elastomer composition obtained, (B) component made of ionic conductive conductive agent, (C) component made of ethylene-acrylic acid ester-maleic anhydride copolymer, polyester type Component (D) comprising a thermoplastic elastomer, calcium carbonate, carbon black, and optionally a blowing agent are kneaded at a temperature of 200 ° C. to obtain pellets of a conductive thermoplastic elastomer composition.

  The pellet-like conductive thermoplastic elastomer composition thus obtained is extruded into a tube shape using a single screw extruder under conditions of 180 to 230 ° C., and a metal core 12 is press-fitted into the hollow part, or both Are bonded and fixed with an adhesive to obtain a conductive roller having a cored bar 12 and a conductive elastic layer 11.

The conductive roller which has not yet been provided with the coating layer 13 manufactured by the above method has a roller resistance value of 10 ⁵ Ω to 10 ⁸ Ω at an applied voltage of 1000 V, and a thickness of only the conductive elastic layer is 1 mm to 6 mm.

  Next, a surface treatment method of the surface treatment liquid on the conductive elastic layer 11, that is, a method of forming the coating layer 13 will be described.

[Method for forming coating layer]
A conductive roller having a core metal 12 and a conductive elastic layer 11 on its outer periphery is immersed (dipped) in a dipping tank containing the surface treatment solution prepared by the above-described method, and then pulled up at 5 mm / sec. A surface treatment liquid is applied to the surface of the elastic elastic layer 11.
Next, the conductive roller coated with the surface treatment liquid is heated in an oven set to a temperature of 130 ° C. or higher and 200 ° C. or lower for 10 to 60 minutes to react and cure the polyol compound and the isocyanate compound in the surface treatment liquid. Thus, a coating layer 13 using a polyurethane resin as a matrix resin is formed.

In the coating layer 13 thus obtained, the carbon nanotubes are 1.0% by mass or more and 3.0% by mass or less, and the polyurethane resin obtained by the reaction of the polyol compound and the isocyanate compound is 92.0% by mass or more and 99.99% by mass. It is contained at a ratio of 0% by mass or less.
The thickness of the coating layer 13 is 5 μm or more and 30 μm or less.

Since the carbon nanotubes are uniformly dispersed in the coating layer 13 of the conductive roller 10 of the present embodiment formed as described above, the conductivity is excellent, and the voltage dependency of the electrical resistance value and the resistance unevenness are present. It is extremely small and does not cause bleeding of the conductive agent. Moreover, since the coating layer 13 uses a polyurethane resin obtained by a heat curing reaction of a polyol compound and an isocyanate compound as a matrix, durability deterioration is suppressed, and a clear image can be obtained over a long period of time.
Moreover, since the surface treatment method uses water as a solvent, the working environment is remarkably improved, and the conductive roller 10 can be made environmentally friendly.

  Hereinafter, although the Example and comparative example of this invention are explained in full detail, this invention is not limited to this.

(Examples 1-5, Comparative Examples 1-4)
[Production of Conductive Roller with Conductive Elastic Layer]
A conductive thermoplastic elastomer composition having the composition shown in Table 1 is used to produce a tube-like extrudate, which is inserted into a cored bar (shaft) to form a base material for forming a coating layer. A conductive roller provided with an elastic layer was produced.

Specifically, the conductive roller was manufactured by the following method.
As the base polymer (A), a thermoplastic elastomer composition in which EPDM was dynamically cross-linked by a resin cross-linking agent and dispersed in a mixture of a styrenic thermoplastic elastomer (SEEPS) and a polypropylene resin (PP) was used.
First, EPDM is pelletized in advance, and the pelletized EPDM, styrene-based thermoplastic elastomer (SEEPS), polypropylene resin (PP), cross-linking agent, and softener are blended in the proportions shown in Table 1 above, After dry blending, the mixture was kneaded at a rotational speed of 200 rpm and a temperature of 200 ° C. with a twin screw extruder (“HTM38” manufactured by Ipec) to produce pellets of a thermoplastic elastomer composition.

  Pellets of the obtained thermoplastic elastomer composition, calcium carbonate, carbon black, ethylene-acrylic acid ester-maleic anhydride copolymer (C) as a compatibilizing agent, ionic conductive conductive agent (B), polyester heat The plastic elastomer (TPEE) (D) was blended in the proportions shown in Table 1 above, dry blended with a tumbler, and then rotated at 200 rpm at a temperature of 200 ° C. using a twin screw extruder (“HTM38” manufactured by Ipec). The mixture was kneaded to obtain conductive thermoplastic elastomer composition pellets.

The obtained pellets of the electrically conductive thermoplastic elastomer composition were extruded into a tube shape at a rotation speed of 20 rpm and a temperature of 200 ° C. using a single-screw extruder (SUNNT φ50 extruder), and extruded with an outer diameter of 12 mm and an inner diameter of 5 mm. A molded product was obtained.
A cored bar having a diameter of 6 mm was inserted into the hollow portion of the obtained tube, and was polished and cut so as to have an outer diameter of 12 mm to obtain a conductive roller.
In addition, the roller resistance value in the applied voltage 500V measured by the method mentioned later of the conductive roller before the surface treatment provided with the conductive elastic layer was 1 × 10 ⁶ Ω.

The materials used are as follows.
In addition, although 100% oil-extended EPDM was used for EPDM, the extended oil of oil-extended EPDM is included in the blending amount of the softening agent in the table, and the value of only the rubber component is described in the EPDM column. That is, in Table 1, since there are 100 parts by mass of EPDM and 174 parts by mass of the softening agent, 100 parts by mass of the extended oil derived from oil-extended EPDM is 174 parts by mass of the softening agent, and the remaining 74 parts by mass are the following commercially available products: Softener.
・ EPDM: “Esplen 670F (trade name)” manufactured by Sumitomo Chemical Co., Ltd. (paraffin oil 100% oil exhibition)
・ SEEPS: Hydrogenated Styrenic Thermoplastic Elastomer (“Septon 4077 (trade name)” manufactured by Kuraray Co., Ltd.)
PP: Polypropylene resin (Novatech PP (trade name) manufactured by Nippon Polychem Co., Ltd.)
・ Crosslinking agent: Halogenated alkylphenol resin cross-linking agent ("Tactrol 250-III (trade name)" manufactured by Taoka Chemical Industry Co., Ltd.)
・ Softener: Paraffinic oil (“Diana Process Oil PW-38” manufactured by Idemitsu Kosan Co., Ltd.)
0 (product name) ")
・ Calcium carbonate: “BF300 (trade name)” manufactured by Shiraishi Calcium Co., Ltd.
・ Carbon black; “Seast 3 (trade name)” manufactured by Tokai Carbon Co., Ltd.
-Compatibilizer; ethylene-acrylic acid ester-maleic anhydride copolymer ("Bondaine LX4110 (trade name)" manufactured by Arkema Co., Ltd.)
Conductive agent: EO-PO-AGE copolymer (“ZSN8030 (trade name)” manufactured by Nippon Zeon Co., Ltd.): Lithium trifluoromethanesulfonate (manufactured by Sanko Chemical Co., Ltd.) = 9: 1 (mass ratio)
TPEE: Polyester-based thermoplastic elastomer (“Hytrel 3078 (trade name)” manufactured by Toray DuPont Co., Ltd.)

  Next, surface treatment liquids of Examples and Comparative Examples were prepared at the blending ratios shown in Tables 2 and 3 below.

[Preparation of surface treatment agent]
(Examples 1-5)
As the carbon nanotube dispersion (CNT dispersion), the following commercially available products in which carbon nanotubes were previously dispersed in water were used.
In the case of blending a polyol compound (main agent) and water, after mixing water and an isocyanate compound (curing agent), the additive, lubricant, and CNT dispersion were blended in this order, and the mixture was stirred and mixed with a stirrer to prepare a surface treatment liquid. .
(Comparative Examples 1-4)
Instead of the CNT dispersion liquid, a conductive carbon dispersion liquid was blended in Comparative Examples 1, 2, and 4, and an ionic conductivity imparting agent was blended in Comparative Example 3 to prepare a surface treatment liquid.

In Tables 2 and 3, specifically, the following products were used.
Main agent 1; hydroxyl group-containing acrylic resin (acrylic polyol): “Baihydrol VPLS2058 (trade name)” manufactured by Sumika Bayer Urethane Co., Ltd.
Main agent 2; hydroxyl group-containing polyurethane resin (urethane polyol): “Baihydrol PT241 (trade name)” manufactured by Sumika Bayer Urethane Co., Ltd.
Curing agent 1: Isocyanate compound (isocyanurate form of hydrophilic group-containing hexamethylene diisocyanate, not blocked): “Baihijur 3100 (trade name)” manufactured by Sumika Bayer Urethane Co., Ltd.
Curing agent 2: Blocked isocyanate compound (hydrophilic group-containing tolylene diisocyanate blocked with oxime): “Takenate WB-700 (trade name)” manufactured by Mitsui Chemicals, Inc.
Additive 1; Wetting agent: “Polyflow KL-510 (trade name)” manufactured by Kyoeisha Chemical Co., Ltd.
Additive 2: Antifoaming agent: “Surfinol 104E (trade name)” manufactured by Nissin Chemical Industry Co., Ltd.
・ Additive 3; Dispersant: “Perex OT-P (trade name)” manufactured by Kao Corporation
・ Water; Purified water / Lubricant: Polyethylene powder “Accumist B-6 (trade name)” manufactured by Toyota Tsusho Corporation
Carbon nanotube (CNT) dispersion 1: “CNF-T / water 5% dispersion” manufactured by Gemco Co., Ltd. (oxidation type, containing 5% by mass of carbon nanotubes, dispersion solvent: aqueous, mixed carbon nanotube powder Volume resistivity 4.0 × 10 ⁻² Ω · cm, diameter 10-20 nm, length 0.1-10 μm)
Carbon nanotube (CNT) dispersion 2; “CNF-T / water 3% dispersion” manufactured by Gemco (surfactant use type, containing 3% by mass of carbon nanotubes, dispersion solvent: aqueous, compounded carbon Volume resistance value of nanotube powder 4.0 × 10 ⁻² Ω · cm, diameter 10-20 nm, length 0.1-10 μm)
-Conductive carbon dispersion; "Lion Paste W-311N (trade name)" manufactured by Lion Corporation (carbon black 16.5% by mass dispersion)
-Ion conductivity imparting agent: “PEL-20A (trade name)” manufactured by Nippon Carlit Co., Ltd.

After applying the surface treatment liquid having the composition shown in Tables 2 and 3 to the outer surface of the conductive elastic layer of the conductive roller prepared previously by dipping, heat curing treatment is performed under the treatment conditions shown in Tables 2 and 3. The electroconductive roller of an Example and a comparative example was produced.
The thickness of the coating layer of the obtained conductive roller was 10 to 20 μm.
The heat treatment was performed in an oven set at 130 ° C.

  The following tests were performed on the obtained conductive rollers of Examples and Comparative Examples, and the results are shown in Tables 2 and 3.

(Initial roller resistance value and uneven resistance)
As shown in FIG. 2, the roller portion 14 of the conductive roller 10 that has passed through the cored bar 12 is mounted on the φ30 aluminum drum 15 in an atmosphere of 23 ° C. and 55% relative humidity. The end of the lead wire with internal resistance r (100Ω to 10 kΩ) connected to the side is connected to one end surface of the aluminum drum 15 and the end of the lead wire connected to the negative side of the power supply 16 is connected to one end surface of the core metal 12 to energize Went. The conductive roller 10 is indirectly rotated by applying a load of 450 g to both ends of the core metal 12 and rotating the aluminum drum 15 at 40 rpm while applying a voltage of 100 V or 500 V between the core metal 12 and the aluminum drum 15. The resistance was measured 36 times in the circumferential direction. In the apparatus of FIG. 2, when the applied voltage is E, the roller resistance value R is R = r × E / V−r, but this time the term −r is regarded as minute, and R = r × E / V, The roller resistance value R was calculated from the detected voltage V applied to the internal resistance r. The value of the internal resistance was adjusted according to the level of the resistance value of the roller so that the effective number of the measured value was as large as possible.
The roller resistance value R was obtained as an average value of 36 times of resistance measurement per round, and resistance unevenness was obtained from the difference between the maximum value and the minimum value of the 36 times of resistance measurement.
Further, the difference between the roller resistance value at 100 V and the roller resistance value at 500 V (100 V roll resistance−500 V roll resistance) was obtained.
In the table, the roller resistance, resistance unevenness, and resistance difference are shown as common logarithmic values (log ₁₀ R).

The roller resistance value at 100 V and 500 V is particularly preferably in the range of 10 ⁵ Ω to 10 ⁸ Ω.
The smaller the resistance unevenness of the roller resistance value is, the better, and at each voltage of 100V and 500V, the level is not problematic as long as it is 1.5 or less.
Also, the smaller the difference between the roller resistance value at 100V and the roller resistance value at 500V, the better. If it is 1.0 or less, there is no problem.

(Paper passing durability test)
The charging roller 31 in the attached toner cartridge (magenta) 40 of a commercially available printer ("C5900dn (trade name)" manufactured by Oki Data Co., Ltd.) having the structure shown in FIG. 3 is used as the conductive roller of each of the examples and comparative examples. The printing was carried out by printing 20000 sheets under conditions of a temperature of 23 ° C. and a relative humidity of 55%.
With respect to the conductive roller after the paper passing durability test, the roller resistance and the resistance unevenness (100 V, 500 V) were measured by the same method as the initial roller resistance and the resistance unevenness.
Further, the printed matter obtained on the 20001th sheet after printing 20000 sheets was visually confirmed for printing density, printing unevenness, white spots, image sharpness, and the like.

In the commercially available printer of FIG. 3, the charging roller 31 is incorporated in the toner cartridge 40 together with the photosensitive drum 32, the developing roller 33 and the like, and the transfer roller 30 is incorporated in the printer. Printing is performed.
The photosensitive drum 32 rotates in the direction of arrow X in the figure, and the photosensitive drum 32 is charged by the charging roller 31. Thereafter, the laser 37 exposes the non-image area of the photosensitive drum 32 to eliminate the charge, and the portion corresponding to the image area is charged. Next, toner (not shown) supplied by the developing roller 33 adheres to the charged image line portion of the photosensitive drum 32 to form a toner image, and an electric field is applied to the toner image on the transfer roller 30. As a result, the image is transferred to the paper 34 conveyed in the arrow Y direction in the figure.

(Preservation test)
As the charging roller 31 of the toner cartridge shown in FIG. 3, the conductive rollers of Examples and Comparative Examples were incorporated and stored for 30 days at a temperature of 50 ° C. and a humidity of 55%. Thereafter, after observing whether or not the charging roller 31 and the photosensitive drum 32 are adhered, a printing (depicting) test is performed, and the obtained printed matter has a printing density, printing unevenness, white spots, and image sharpness. Etc. were observed visually.

As shown in Tables 2 and 3, the conductive rollers of Comparative Examples 1, 2, and 4 containing only conductive carbon black as the conductive agent of the coating layer were at 100 V both in the initial stage and after the paper passing durability test. The resistance unevenness is as large as 10 4.9 Ω or more, and the difference between the electrical resistance values of 100 V and 500 V is as large as 10 1.8 Ω or more, and there are many white spots in the printed image after the paper passing durability test. Occurred. Furthermore, in the printing test after the storage test, the image was blurred, and a clear printed image could not be obtained.
Further, the conductive roller of Comparative Example 3 using an ionic conductivity imparting agent as the conductive agent for the coating layer has no problem with the roller resistance value and the printed image after the initial and paper passing durability test, but after the storage test. Showed sticking to the photoreceptor, and a large number of horizontal streaks occurred in the printed image.

In contrast, the conductive rollers of Examples 1 to 5 in which carbon nanotubes were blended as a conductive agent for the coating layer had both roller resistance values of 100 V and 500 V in appropriate ranges both at the initial stage and after the paper passing durability test. And the resistance unevenness was small. Further, even after the paper passing durability test, the resistance difference between 100 V and 500 V was as small as 10 to the power of 1.0 or less, and the voltage dependency of the electrical resistance value was small, so that a good printed image was obtained.
In addition, a clear printed image was obtained without sticking to the photoreceptor even after the storage test.
Thus, the conductive rollers of Examples 1 to 5 were excellent in printing characteristics while maintaining good charging characteristics and storability over a long period while effectively preventing durability deterioration.

(A) of the electroconductive roller of embodiment is a schematic perspective view, (B) is a cross-sectional block diagram. It is the schematic of the measuring apparatus of the roller resistance value of an electroconductive roller. FIG. 4 is a diagram illustrating a toner cartridge and a printer used for a paper passing durability test and a storage test of a conductive roller.

Explanation of symbols

10 conductive roller 11 conductive elastic layer 12 cored bar (shaft)
13 Coating Layer 14 Roller Part 15 Aluminum Drum 16 Power Supply

Claims (8)

A surface treatment liquid for coating the surface of a conductive member,
A surface treatment liquid, wherein carbon nanotubes are dispersed in a medium containing a polyol compound and an isocyanate compound and / or a reaction product of the polyol compound and an isocyanate compound.   The surface treatment liquid according to claim 1, wherein the carbon nanotube is contained at a ratio of 0.1% by mass or more and 1.0% by mass or less.   The surface treatment liquid according to claim 1 or 2, wherein the carbon nanotubes are contained in a total solid content in a proportion of 0.5% by mass or more and 5.0% by mass or less.   The surface treatment liquid according to any one of claims 1 to 3, wherein the polyol compound is an acrylic polyol or a urethane polyol.   The surface treatment liquid according to claim 1, wherein a hydrophilic group is introduced into the isocyanate compound, and the medium contains 50% by mass or more of water. A conductive member comprising a conductive elastic layer formed using at least one elastic material selected from the group consisting of rubber, resin and thermoplastic elastomer, and a coating layer covering the surface of the conductive elastic layer Because
The conductive member is characterized in that carbon nanotubes are dispersed in a polyurethane resin obtained by thermosetting a polyol compound and an isocyanate compound.   The conductive member according to claim 6, which is a conductive roller mounted on the image forming apparatus.   A conductive elastic layer formed by using the surface treatment liquid according to any one of claims 1 to 5 using at least one elastic material selected from the group consisting of rubber, resin, and thermoplastic elastomer. A method for surface treatment of a conductive elastic layer, wherein a coating layer is formed by applying a heat-curing treatment after coating on an outer surface.

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