JP2002266844A - Conductive roller and electrophotographic recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conductive roller excellent in charging property, leakage resistance, and durability, and not susceptible of damaging a photoreceptor because the irregular resistance caused by change in external environment is reduced as much as possible and the surface is sufficiently smooth. SOLUTION: In the conductive roller, at least a conductive elastic body layer 22 and a covering film 23 are laminated in this order on an outer periphery of a shaft 21 of good conductor. A value of volume resistivity of the coating film is larger than that of a whole of the shaft and the conductive elastic body layer. The coating film contains water soluble conductive polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive roller for developing, charging, discharging, transferring, etc., which is suitably disposed in an electrophotographic recording apparatus and the like. The present invention relates to a conductive roll having a conductive elastic layer on the outer periphery of a good conductor metal shaft, and further having a coating film having a high volume resistance value formed on the outer peripheral surface thereof.

[0002]

2. Description of the Related Art An electrophotographic recording apparatus widely used in copiers, laser beam printers, and the like generally includes a photosensitive member, and charges and exposes the photosensitive member to form an electrostatic latent image. I do. Subsequently, toner is attracted and developed according to the latent image on the photoconductor, and then the toner on the photoconductor is transferred and transferred to paper. Thereafter, the photosensitive member is neutralized to a predetermined potential and the residual toner on the photosensitive member is cleaned to prepare for the next recording. Further, the toner carried on the sheet after the transfer is finally melted and pressed to be fixed on the sheet, thereby completing a series of recording operations on the sheet.

By the way, a charging means for applying a predetermined potential to a charged area of a photosensitive member of such an electrophotographic recording apparatus, and a transfer means for applying a predetermined potential to a sheet conveyed to a transfer area. For example, a corona charging method in which a high-voltage of several hundred to several thousand volts is applied to a small-diameter wire to generate a corona discharge in a means or a static elimination means for making a charged area of a photoconductor after transfer uniform to a constant potential. Widely and generally employed.

However, the corona discharge method requires a high-voltage power supply and uses corona discharge, so that there is a concern that ozone, which is an undesirable active molecule, is generated.

On the other hand, for such a corona discharge device,
A method in which a predetermined voltage is applied by directly contacting a conductive roller has been proposed. The method using this conductive roller has the advantages that the pressure of the power supply can be reduced and the amount of ozone generated as active molecules is small. have.

As the conductive roller, a structure in which at least two or more electric resistance layers are provided on a shaft of a good conductor has been proposed. In such a structure, the external resistance layer retains an appropriate surface resistance, and the internal resistance layer retains an appropriate elasticity in order to secure an appropriate nip width with respect to the contact surface. Adhesion to the surface of the member to be charged is high, and it is possible to prevent leakage caused by pinholes and scratches on the surface of the member to be charged such as the photosensitive member.

[0007]

The performance required for the surface layer material having the above-mentioned structure is, firstly, uniformity of electric resistance. That is, if there is no partial unevenness in the electric resistance, it is possible to suppress the concentration of the electric charge at a place where the resistance value is low, and to suppress the excessive current from flowing locally. As a result, image defects due to uneven charging and leakage are suppressed, and problems such as destruction of the photoconductor are also suppressed.

For example, a transfer roller used in an image forming apparatus such as a copying machine is a member for transferring a toner image on an image carrier such as a photoreceptor, an intermediate transfer body and a transfer drum onto a transfer paper. The transfer roller is pressed against the photoreceptor or the like on which the image has been developed via transfer paper as a transfer target, and a charge having a polarity opposite to that of the toner of the toner image is supplied, so that the toner of the photoreceptor or the like is attracted to the paper. Transcribe.

In such a transfer roller, the magnitude of the charge density supplied to the transfer paper greatly affects the image quality.

[0010] That is, if the charge density is sufficient, the toner has a sufficient attraction force, so that the occurrence of “scatter” is suppressed even in the case of dry paper. Conversely, if the charge density is not too high, the occurrence of “bleeding” due to the opposite polarity charging of the toner is suppressed, and a high-quality image can be obtained. Further, if the charge density is uniform, it is possible to suppress the occurrence of density unevenness in solid black transferability and the occurrence of spot-like transfer unevenness such as sand.

Therefore, it is important that the conductive rollers such as the transfer roller and the charging roller and the developing roller have uniform surface conductivity.

When a conductive agent particle dispersing material is used from the viewpoint of making the surface conductivity uniform, the uniform dispersibility is important. For example, JP-A-10-171212, JP-A-10-177188, and JP-A-10-17728
No. 9, JP-A-10-177290 and the like, conductive carbon such as Ketjen Black EC and acetylene black, or Ketjen Black EC or acetylene black as conductive particle dispersing material for imparting conductivity to the surface layer of the roller Zinc oxide,
When titanium oxide, tin oxide, hydrophobic silica, or the like is used, the electrical resistance value may change significantly due to a slight change in the amount of the powder to be added or poor dispersion of the powder.

Further, in such a conductive roller, it may be difficult to control and adjust the electric resistance value, and it may be difficult to provide necessary charged voltage characteristics.

In addition, in such a conductive roller, the electric resistance value may change significantly with the change of the external environment such as humidity and temperature, so that a constant value is always applied to the photosensitive member. In some cases, it was difficult to apply a potential.

Further, the surface layer material of such a conductive roller is fragile in material and easily cracked.
Sometimes it was easy to wear.

The present invention has been made in view of the above situation, and an object of the present invention is to minimize surface resistance non-uniformity due to external environmental changes and the like, and to provide a sufficiently smooth surface, and An object of the present invention is to provide a conductive roller which has little damage to a body, is excellent in chargeability and leak resistance, and has excellent durability.

[0017]

According to the present invention, there is provided a conductive roller in which a conductive elastic layer and a coating film are laminated at least on the outer periphery of a good conductor shaft in this order. The volume resistance of the coating film is larger than the volume resistance value of the entire shaft and the conductive elastic layer, and the coating film contains a water-soluble conductive polymer. A conductive roller is provided.

In the present invention, by dispersing the water-soluble conductive polymer in the coating film, the electric resistance value can be stabilized in the semiconductive region and a uniform conductive distribution can be obtained.

That is, by using a water-soluble conductive polymer as a conductivity-imparting agent for the surface material serving as the coating film, a desired electric resistance value can be realized, and a uniform electric resistance value can be realized. The reason for this is not clear, but it is presumed that the water-soluble conductive polymer is dispersed well in the coating film. As a result, it is considered that uniformity of the electric resistance value and surface smoothness can both be achieved.

Further, by setting the magnitude of the volume resistance value of the coating film larger than the magnitude of the volume resistance value of the entire shaft and the conductive elastic material layer, it is possible to realize good leak resistance.

Such a conductive roller is particularly suitable as a charging member such as a charging roller, a transfer roller, a developing roller, and a charge removing roller provided in an electrophotographic recording apparatus.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

In the present invention, in a conductive roller in which a conductive elastic layer is disposed on the outer periphery of a metal shaft of a good conductor and a high-resistance coating film is formed on the outer peripheral surface, a water-soluble polymer is used as a binder. The coating film is formed by uniformly dispersing the conductive polymer. Note that a binder refers to a polymer that can uniformly contain a water-soluble conductive polymer or the like in a coating film.

By dispersing the water-soluble conductive polymer in the coating film, it is possible to stabilize the resistance value in the semiconductive region and obtain a uniform conductive distribution.

That is, by using a water-soluble conductive polymer as a conductivity-imparting agent for a surface layer material to be a coating film and mixing it with a surface layer binder material in a specific ratio, a desired electric resistance value can be realized and a uniform electric resistance can be obtained. A resistance value can be realized. The reason for this is not clear, but it is presumed that the water-soluble conductive polymer can be mixed with the binder with good dispersibility. As a result, a uniform dispersion of both materials is obtained, and it is considered that uniformity of electric resistance value and surface smoothness can be compatible.

The water-soluble conductive polymer used in the present invention is not a polymer exhibiting ionic conductivity whose electric resistance largely depends on humidity, but has a humidity dependency due to its structurally electronic conductivity. An aniline-based conductive polymer is effective because it is hard to receive.

Among the aniline-based conductive polymers, poly (aniline sulfonic acid) is preferable from the viewpoint of solubility in water, and more specifically, from the group consisting of aniline, N-alkylaniline and phenylenediamines. A polymer obtained by copolymerizing at least one selected compound with an alkoxy-substituted aminobenzenesulfonic acid is preferable.

The amount of the water-soluble conductive polymer to be added to the binder is preferably 10% by mass or more in order to realize a desired electric resistance value and to form a good image. On the other hand, the content is preferably 50% by mass or less in order to achieve uniform dispersion, suppress excessive discharge due to unnecessary conductivity, and form a coating film that is flexible and suppresses cracking and abrasion.

Examples of the polymer serving as a binder include polyamide such as nylon, acrylic polymer, polyvinyl butyral, polyvinyl acetal, polyarylate, polycarbonate, polyester, phenoxy resin, polyvinyl acetate, polyvinyl pyridine, and cellulose resin.
Examples include resins and elastomers such as polyurethane, silicone, polyolefin, polystyrene, and the like.

As the rubber material, for example, EPDM
(Ethylene-propylene-diene-terpolymer), polybutadiene, natural rubber, polyisoprene, SBR (styrene butadiene rubber), CR (chloroprene rubber),
NBR (nitrile butadiene rubber), silicone rubber,
Rubber such as urethane rubber and epichlorohydrin rubber, and B
Polymer materials such as polystyrene elastomers such as R (butadiene resin) and SBS (styrene-butadiene-styrene elastomer), polyolefin elastomers, polyester elastomers, and polyurethane elastomers can be used.

Among these, from the viewpoints of flexibility, mechanical strength, abrasion resistance and the like, a binder mainly composed of at least one of polyurethane and polyamide is more suitable.

Further, from the viewpoints of solubility and dispersibility, a binder that is soluble in at least one solvent selected from the group consisting of water, an alcohol-based solvent, and a mixture thereof is more preferable.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration example of the conductive roller of the present invention.

The conductive roller of this embodiment has a conductive elastic layer 22 provided on a cylindrical conductive column support (shaft) 21 made of metal or the like, and a coating film 23 provided thereon.

As the conductive columnar support (shaft),
Metal shafts such as iron, aluminum alloy, SUS, and brass are preferably used.

The conductive elastic material layer may be any material as long as it can apply a bias voltage and has elasticity enough to make uniform pressure contact.
^It is preferably from ⁴ Ω · cm to 1 × 10 ¹² Ω · cm.

Examples of the elastic body of the conductive elastic layer include EPDM (ethylene-propylene-diene-terpolymer), polybutadiene, natural rubber, polyisoprene, SBR (styrene-butadiene rubber), CR (chloroprene rubber), and NBR. (Nitrile butadiene rubber), rubber such as silicone rubber, urethane rubber, epichlorohydrin rubber, polystyrene elastomer such as BR (butadiene resin), SBS (styrene-butadiene-styrene elastomer), polyolefin elastomer,
A thermoplastic elastomer polymer material such as a polyester elastomer, a polyurethane elastomer, and a nylon elastomer can be used.

The form of use of the elastic body may be solid or foam.

In order to make these elastic bodies semiconductive, metal oxides such as carbon black, graphite, titanium oxide and tin oxide, metals such as Cu and Ag, and particles obtained by coating these on the particle surface and making them conductive. Conductive particles such as LiCl
O ₄ , KSCN, NaSCN, LiSCN and LICF ₃
By appropriately dispersing an ionic electrolyte such as SO ₃ in the elastic layer, a desired electric resistance value can be adjusted.

It is also possible to make the polymer semiconductive by introducing a molecule or an atomic group having polarity in the main chain or on the side chain of the polymer, or by introducing a molecule or an atomic group forming an ion pair.

The conductive elastic layer as described above is formed by extrusion molding,
It can be formed by a method such as injection molding.

A coating film is formed on the conductive elastic layer obtained as described above by a method such as coating, dipping, spraying and the like.

The thickness of the coating film is generally 5 μm or more and 200 μm or less.

The volume resistance value of the shaft and the entire conductive elastic layer is determined by measuring the distance between the shaft and the metal drum when the roller before forming the coating film is in contact with the cylindrical metal drum and rotated. A voltage of 500 V DC or 1 kV is applied to the resistor, a voltage applied to a resistor connected in series with the metal drum is measured, a contact width with the drum is determined in advance, and a resistance value obtained using the contact area is determined as a volume resistance. It was converted to a value.

Further, the volume resistance value of the coating film is JIS540
0 and a thickness of 0,0 using a film applicator.
After forming a coating film on aluminum of 1 mm, it was dried for a predetermined time, an electrode was attached thereto, a voltage of 100 V was applied, the resistance value was measured, and the volume resistance value was obtained by normalization.

In addition, the volume resistance of the conductive roller is determined by contacting the obtained conductive roller with a cylindrical metal drum.
While rotating, direct current 50 between shaft and metal drum
A voltage of 0 V or 1 kV is applied, a voltage applied to a resistor connected in series with the metal drum is measured, a contact width with the drum is determined in advance, and a resistance value obtained using this contact area is converted into a volume resistance value. Converted.

FIG. 2 shows an example of the configuration of an electrophotographic recording apparatus using the conductive roller of the present invention.

Reference numeral 1 denotes a photoreceptor as a member to be charged. In this embodiment, a drum-type electrophotograph having a conductive support layer 1b made of aluminum or the like and a photosensitive layer 1a formed on the outer peripheral surface thereof as a basic constituent layer. It is a photoconductor. It is driven to rotate around the support shaft 1d clockwise in the drawing at a predetermined peripheral speed.

Reference numeral 2 denotes a charging member which contacts the surface of the photosensitive member 1 and uniformly performs primary charging on the surface of the photosensitive member to a predetermined polarity and potential. In this embodiment, the charging member is of a roller type (hereinafter also referred to as a charging roller). . As described above, the charging roller 2 includes a center core 2c and a lower conductive elastic layer 2b formed on the outer periphery thereof.
And an upper coating film 2d formed on the outer periphery thereof, and both ends of the cored bar 2c are driven to rotate by rotation of the photoconductor 1 by a pressing means (not shown).

A predetermined direct current (DC) bias or a direct current + alternating current (DC + AC) bias is applied to the metal core (shaft) 2c by the rubbing power source 3a. The peripheral surface is contact-charged to a predetermined polarity and potential. The surface of the photoreceptor 1 which has been uniformly charged by the charging roller 2 is then subjected to exposure of target image information (laser beam scanning exposure, slit exposure of a document image, etc.) by the exposure means 10 so that the peripheral surface thereof An electrostatic latent image corresponding to the image information is formed.

The latent image is then visualized sequentially by the developing means 11 as a toner image. The toner image is then transferred by a transfer unit 12 from a paper supply unit (not shown) to a transfer unit between the photosensitive member 1 and the transfer unit 12 at an appropriate timing in synchronization with the rotation of the photoconductor 1. It is sequentially transferred to the surface of the material 14. The transfer unit 12 of this embodiment is a transfer roller, and the toner image on the photoconductor 1 side is transferred to the front side of the transfer material 14 by performing charging of the opposite polarity to the toner from the back of the transfer material 14.

The transfer material 14 to which the toner image has been transferred is separated from the surface of the photoreceptor 1, conveyed to an image fixing means (not shown), subjected to image fixing, and output as an image formed product. Alternatively, in the case of forming an image on the back surface, the sheet is conveyed to a re-conveying unit to the transfer unit.

After the transfer of the image, the surface of the photoreceptor 1 is cleaned by the cleaning means 13 to remove adhered contaminants such as untransferred toner, and is repeatedly subjected to image formation.

The roller type charging member 2 may be driven by the surface-moved member 1 to be driven, may be non-rotating, or may be in the forward direction in the surface movement direction of the member 1. Alternatively, the motor may be positively driven to rotate at a predetermined peripheral speed in the opposite direction.

Further, as the electrophotographic recording apparatus, a plurality of components such as the above-described photosensitive member, developing means, and cleaning means are integrally connected as an apparatus unit, and this unit is attached to the apparatus main body. May be configured to be detachable. For example, a unit is formed by integrally supporting at least one of the charging unit, the developing unit, and the cleaning unit together with the photoreceptor, as a single unit detachable from the apparatus main body, and using a guide unit such as a rail of the apparatus main body. You may make it a detachable structure. At this time, the above-mentioned device unit may be provided with a charging unit and / or a developing unit.

In the case of using the electrophotographic recording apparatus as a copier printer, the light image exposure is performed by reflecting or transmitting light from the original or by reading the original into a signal and scanning the laser beam with the signal. Or by driving an LED array or a liquid crystal shutter array.

[0058]

EXAMPLE The conductive roller shown in FIG. 1 was manufactured as follows when the conductive elastic layer 22 was a foamed EPDM rubber or silicone rubber layer.

Unless otherwise specified, “parts” and “%” represent “parts by mass” and “% by mass”, respectively.
Commercially available high-purity reagents were used.

Example 1 A charging roller was manufactured. That is, EPDM is used as a sponge material for the conductive elastic part.
(Trade name: F600, manufactured by Sumitomo Chemical) 8 parts of conductive carbon black (trade name: Ketjen Black, manufactured by Mitsubishi Chemical) for imparting conductivity to 100 parts, paraffin oil (trade name: PW380, manufactured by Idemitsu Kosan) 50 parts Further, 10 parts of ADCA (trade name: Vinyl Hole AC # 3C, manufactured by Eiwa Chemical Co., Ltd.) was added as a foaming agent for foaming during vulcanization.

The obtained rubber is molded into a tube by extrusion molding, a shaft made of SUS is inserted, primary vulcanization is performed by a steam vulcanization method to form a foam, and secondary vulcanization is performed in an electric furnace. A conductive elastic layer was formed.

With respect to the obtained sponge roller, the total volume resistance of the shaft and the conductive elastic layer was set at 23 ° C.
60% R.C. H. It was 7 × 10 ⁵ Ω · cm when measured at 500 V after being left for one week in the environment. The dimensions of the roller were 12 mm in diameter and 230 mm in length.

An adhesive (trade name: CHEMLK459X, Road Far East Co., Ltd.) was applied to the obtained sponge roller.
Incorporated) and apply at 120 ° C for 10
Heat treatment for one minute.

Next, a coating layer was formed on the sponge roller after the bonding treatment as follows. That is, a self-emulsifying water-soluble urethane resin (trade name: Superflex 460 (solid content: 38%, manufactured by Daiichi Kogyo Seiyaku)) and poly (aniline sulfonic acid) (trade name: aq) as a water-soluble conductive polymer.
ua PASS-01x (5% product, manufactured by Mitsubishi Rayon)
Was added. The compounding amount was 30% by mass of the solid content with respect to the resin (binder) component in the paint.

In the mixing method, the water-soluble conductive polymer can be uniformly dispersed in the resin (binder) by simply mixing with a stirrer or the like, but it is also possible to use an appropriate disperser as appropriate. is there.

The mixture thus prepared was applied to the surface of the sponge roller which had been subjected to the above-mentioned adhesive treatment by a dipping coating method. In the dipping coating, the film was inverted twice and the coating was performed twice so that the finally obtained film thickness was 80 μm. The volume resistance value of the coating film is 1 × 10 ⁸ Ω · c
m.

As a coating method, besides the dipping coating method, a roll coating method, a beam coating method, or the like can be appropriately used.

The coated roller was dried at 120 ° C. for 30 minutes. The volume resistance value of the obtained roller is 6 × 10
It was ⁶ Ω · cm. The surface roughness of the roller was 6 μm in Rz.

The charging roller manufactured as described above is shown in FIG.
AC charging method (applied voltage DC-700)
The image was evaluated at V, AC 500 Hz, and 2000 Vpp (sine wave). As a result, the photosensitive member could be uniformly charged to -700 V under all environments including high-temperature, high-humidity and low-temperature, low-humidity environments.

When an image was formed in the same manner using a photoreceptor having artificially formed pinholes, no abnormal image possibly caused by leakage or the like was generated.

Further, when a durability test of 20,000 sheets was performed,
There were no abnormal images due to scraping of the photoreceptor and no filming due to toner adhesion, and the same results as in the initial stage were obtained.

(Example 2) Soluble nylon (trade name: CM4000, manufactured by Toray) was used as a binder, and 10% was dissolved in methanol / water = 85/15 (volume ratio). (Aniline sulfonic acid) (trade name aqua PASS-01)
x (5% product, manufactured by Mitsubishi Rayon). The amount of the water-soluble conductive polymer is 40% of the binder.
(Mass ratio of solid content).

The raw materials for forming the coating film are mixed as described above.
A roller was prepared in the same manner as in Example 1 except that
As a result, the volume resistance value of the finally obtained roller was 1 ×
10 ⁷Ω · cm, and the surface roughness was 8 μm in Rz.
The total volume resistance of the shaft and the conductive elastic material layer
Is 7 × 10^FiveΩ · cm, volume resistance value as a coating film
Is 5 × 10⁸Ω · cm.

When the charging roller thus manufactured was subjected to image evaluation, it was possible to uniformly charge the photosensitive member under all environments including a high-temperature, high-humidity environment and a low-temperature, low-humidity environment.

When an image was formed in the same manner as in Example 1 using a photoreceptor having artificially formed pinholes, no abnormal image caused by leakage or the like was generated.

Further, when a durability test of 20,000 sheets was performed,
There were no abnormal images due to scraping of the photoreceptor and no filming due to toner adhesion, and the same results as in the initial stage were obtained.

Comparative Example 1 The same binder as in Example 1 was used as the binder, and the conductive carbon black (trade name Ketjen Black, Mitsubishi Chemical Corporation) was used without using the water-soluble conductive polymer as the conductivity-imparting material. Roller was produced in the same manner as in Example 1, except that 10% by mass of the binder was added to the binder. The volume resistance value of the finally obtained roller was 3 × 10 ⁵ Ω · cm, and the surface roughness was about 20 μm in Rz. The volume resistivity of the coating film was 2 × 10 ⁵ Ω · cm.

When a test similar to that of Example 1 was performed using this roller, a decrease in roller resistance was observed in a high-humidity and high-temperature environment. As a result, poor charging occurred with respect to chargeability. Regarding durability, toner filming occurred due to shavings of the photoreceptor generated by drum scraping on 3,000 sheets, and an abnormal image occurred. In addition, poor charging occurred in part.

(Comparative Example 2) The same binder as in Example 1 was used as the binder, and the water-soluble conductive polymer was not used as the conductivity-imparting material.
% By mass of SnO ₂ · Sb ₂ O ₅ and 2
A roller was produced in the same manner as in Example 1 except that 0% by mass of SnO ₂ was blended. The volume resistance value of the finally obtained roller was 2 × 10 ⁵ Ω · cm, and the surface roughness was about 5 μm in Rz. The volume resistance value of the coating film is 1
× was 10 ⁵ Ω · cm.

When the same test as in Example 1 was performed using this roller, the same result was obtained in terms of the charging property. However, in terms of the durability, the photoreceptor shaving caused by the drum shaving was 3,000 sheets. Powder caused toner filming on the photoreceptor, causing an abnormal image.

Example 3 Next, a transfer roller was manufactured. That is, a foamed EPD rubber layer was formed as a sponge material of the conductive elastic body by the following method.

The sponge was made of EPDM (trade name: F60).
0, manufactured by Sumitomo Chemical Co., Ltd., 60 parts of furnace carbon black (trade name: HAF Carbon, manufactured by Tokai Carbon) and paraffin oil (trade name: PW
380, manufactured by Idemitsu Kosan Co., Ltd., 70 parts, and ADCA (trade name: VINHALL A)
C # 3C, manufactured by Eiwa Kasei Co., Ltd.).

The obtained rubber is formed into a tube by extrusion, a shaft made of SUS is inserted, primary vulcanization is performed by a steam vulcanization method to form a foam, and secondary vulcanization is performed in an electric furnace. A conductive elastic layer was formed.

With respect to the obtained sponge roller, the total volume resistance of the shaft and the conductive elastic layer was set to 23 ° C.
60% R.C. H. Was measured at 1 week after leaving 1kV applied to the environment, was 1 × 10 ⁹ Ω · cm. The dimensions of the roller were 20 mm in diameter and 230 mm in length.

Next, a coating film was formed. That is, a self-emulsifying water-soluble urethane resin (trade name: Superflex 11)
0 (solid content 30% product, manufactured by Dai-ichi Kogyo Seiyaku)) and poly (aniline sulfonic acid) as a water-soluble conductive polymer
(Trade name aqua PASS-01x (5% product), manufactured by Mitsubishi Rayon) was added. The compounding amount was 10% by mass of the solid content with respect to the resin (binder) component in the paint. The coating had a volume resistivity of 6 × 10 ¹⁰ Ω · cm.
Met.

This mixture was applied onto the above-mentioned roller which had been subjected to an adhesive treatment in the same manner as in Example 1, and dried as in Example 1. The number of dips was one. The film thickness was 20 μm.

The volume resistance of the obtained roller was 2 × 10 ⁹
Ω · cm, and the surface roughness Rz was 6 μm.

Using the transfer roller manufactured as described above, the transfer voltage was -5 kV, and the cleaning voltage was +1.5 kV.
When a line drawing, a solid black and a halftone image were formed using dry paper, a clear image was obtained without density unevenness and without spot-like transfer unevenness such as sand.

Further, when a durability test was conducted on 200,000 sheets, there was no breakage of the surface layer due to abrasion or the like, and no cracks or the like were generated, and the same result as in the initial stage was obtained.

Example 4 A developing roller was manufactured as follows.

Set the SUS shaft in the cylindrical mold,
Liquid conductive silicone rubber compound (trade name SCL
35-09, manufactured by Toray Down Corning Silicone), and the entire roller mold was heated at 150 ° C. for 30 minutes to vulcanize the silicone rubber compound. Then, after heating and vulcanization, it was taken out of the roller mold, and the residue of the vulcanizing agent was evaporated by secondary vulcanization (200 ° C. × 4 hours) to form a conductive elastic layer.

With respect to the obtained roller, the total volume resistance of the shaft and the conductive elastic layer was adjusted to 23 ° C., 60%
R. H. It was 1 × 10 ⁵ Ω · cm when measured by applying 500 V after being left for one week in an environment. The dimensions of the roller were 16 mm in diameter and 240 mm in length.

Next, a coating film was formed. That is, a self-emulsifying water-soluble urethane resin (trade name: Superflex 46)
0 (38% solid content, manufactured by Dai-ichi Kogyo Seiyaku) and poly (aniline sulfonic acid) as a water-soluble conductive polymer
(Trade name aqua PASS-01x (5% product), manufactured by Mitsubishi Rayon) was added. The compounding amount was 40% in terms of a solid content mass ratio with respect to the resin (binder) component in the above coating material.

This mixture was applied on the roller which had been subjected to the bonding treatment in the same manner as in Example 1, and dried in the same manner as in Example 1. The number of dips was one. The film thickness was 40 μm.

The volume resistance value of the obtained roller was 4 × 10 ⁶
Ω · cm, and the surface roughness Rz was 9 μm. In addition, the volume resistance value as a coating film was 2 × 10 ⁷ Ω · cm.

When the electric resistance was measured in a high-temperature and high-humidity (32 ° C. × 80%) and low-temperature and low-humidity (10 ° C. × 15%) environment, the resistance fluctuation due to the environmental fluctuation was extremely small at 0.7.

Further, when this roller was incorporated into the apparatus and the image quality was evaluated, a good image was obtained after copying 30,000 sheets, as well as the image quality at the beginning of copying. From this, it was found that an image which was sharp and free from toner filming was obtained over a long period of time.

Example 5 Soluble nylon (trade name: CM4000, manufactured by Toray Co., Ltd.) was used as a binder, and 10% was dissolved in methanol / water = 85/15 (volume ratio). (Aniline sulfonic acid) (trade name aqua PASS-01)
x (5% product, manufactured by Mitsubishi Rayon). The amount of the water-soluble conductive polymer is 50% of the binder.
(Mass ratio of solid content).

A roller was produced in the same manner as in Example 4 except that the raw material for forming the coating film was changed to the above mixture.

The finally obtained roller had a volume resistance of 1
× 10 ⁶ Ω · cm, and the surface roughness Rz was about 6 μm. The total volume resistance of the shaft and the conductive elastic layer was 1 × 10 ⁵ Ω · cm, and the volume resistance of the coating film was 2 × 10 ⁶ Ω · cm.

When the electric resistance was measured in a high-temperature and high-humidity (32 ° C. × 80%) and low-temperature and low-humidity (10 ° C. × 15%) environment, the resistance fluctuation due to the environmental fluctuation was extremely small at 0.6.

Further, when this roller was incorporated in the apparatus and the image quality was evaluated, a good image was obtained after copying 30,000 sheets as well as the image quality at the initial stage of copying. From this, it was found that an image which was sharp and free from toner filming was obtained over a long period of time.

[0103]

As described above, the core has the conductive elastic layer on the outer periphery of the shaft of a good conductor, and the coating film having a larger volume resistance value than the shaft and the conductive elastic layer is formed by the conductive elastic layer. Provided on the outer periphery of the body layer, in a conductive roller that imparts a predetermined polarity and potential while contacting the photoconductor or transfer paper, by forming a coating film from a mixture of a water-soluble conductive polymer and a binder, A charging member which has a small resistance unevenness on the surface, has a smooth surface property, and therefore has little damage to the photoreceptor, etc., is capable of uniform charging, has excellent leak resistance, and has excellent durability. An image forming apparatus such as an electrophotographic recording apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining a structural example of a conductive roller of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a structural example of an electrophotographic recording apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoreceptor 1a Photosensitive layer 1b Conductive support layer 1d Support shaft 2 Charging roller 2b Conductive elastic layer 2c Metal core (shaft) 2d Coating film 3 Power supply 3a Printing power supply 10 Photosensitive means 11 Developing means 12 Transfer means 13 Cleaning means 14 Transfer material 21 Shaft 22 Conductive elastic layer 23 Coating film

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H035 AA15 2H077 AD06 FA13 FA16 FA22 FA26 FA27 2H200 FA09 HA03 HB12 HB22 HB45 HB46 HB47 JA02 JA25 JA26 JA27 JB10 MA01 MA03 MB01 MC01 3J103 AA02 AA14 AA51 GA41 GA18 GA30 GA66 GA74 HA04 HA20 HA53 HA60

Claims (8)

[Claims] At least in a conductive roller having a conductive elastic layer and a coating film laminated in this order on the outer periphery of a good conductor shaft, the magnitude of the volume resistance of the coating film is determined by the shaft and the shaft. A conductive roller, wherein the coating film contains a water-soluble conductive polymer which is larger than the volume resistance value of the entire conductive elastic layer. 2. The conductive roller according to claim 1, wherein the water-soluble conductive polymer is an aniline-based conductive polymer. 3. The conductive roller according to claim 2, wherein the aniline-based conductive polymer is poly (aniline sulfonic acid). 4. The coating film comprises a binder,
4. The conductive roller according to claim 1, wherein the binder is mainly made of at least one of polyurethane and polyamide. 5. The coating film comprises a binder,
The conductive roller according to any one of claims 1 to 4, wherein the binder is soluble in at least one solvent selected from the group consisting of water, an alcohol-based solvent, and a mixture thereof. 6. The conductive roller according to claim 4, wherein a blending amount of the water-soluble conductive polymer with respect to the binder is 10% by mass or more and 50% by mass or less. 7. An electrophotographic recording apparatus, comprising a charging member comprising the conductive roller according to claim 1. 8. The electrophotographic recording apparatus according to claim 7, wherein said charging member is at least one kind of roller selected from the group consisting of a charging roller, a transfer roller, a developing roller and a charge removing roller.