JPH07332350A - Electric conductive roll - Google Patents

Abstract

PURPOSE:To provide an electric conductive roll which has a superlow hardness and a small permanent compression strain. CONSTITUTION:On the outer peripheral surface of a shaft body 12, a basic layer 14 which is constituted of the reaction hardened substance between the both-terminal hydroxyl group containing polyolefine group polyol and isocyanate and contains the petroleum based softening agent in 80 pts.wt. or greater for 100 pts.wt. of the both-terminal hydroxyl based containing polyolefine based polyol and has a hardness (Hs : JIS A) of 20 or less is formed, and further, on the outer peripheral surface of this basic layer 14, an electric conductive coated layer is formed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conductive roll such as a charging roll and a developing roll used in a copying machine or a printer using an electrophotographic system, and particularly to a conductive roll having an extremely low hardness and a small compression set. It is about.

[0002]

2. Description of the Related Art Conventionally, various electroconductive rolls have been used in copiers, printers and the like using an electrophotographic system. For example, in a copying machine, as shown in FIG. 3, a charging roll 34 that charges the surface of the photoconductor (drum) 32 and a toner corresponding to the electrostatic latent image formed on the surface of the photoconductor 32 by the exposure mechanism section 36. Image development roll 3
8. A transfer mechanism unit 42 for transferring the toner image onto the copy paper 40, and a cleaning roll 46 for removing the transfer residual image and the residual toner on the surface of the photoconductor 32 in the cleaning unit 44 after the transfer are used as a conductive roll. It is being done. In FIG. 3, reference numeral 48 is a fixing roll for fixing the toner image transferred to the copy paper 40, 50 is a paper feed roll, and 52 is an eraser lamp.

In general, these conductive rolls have (a) low hardness and excellent contact with a photoreceptor, so-called photosensitive material contact, and (b) softening agent or the like on the roll surface. That the photoreceptor is not contaminated by bleeding into the photosensitive material, that is, the contamination of the photosensitive material is small, (c) the electric resistance is controlled in an appropriate range, and (d) the adhesiveness is small, It is required.

Therefore, the applicant of the present application has previously proposed that the Japanese Patent Application Laid-Open No.
In 311868, etc., a conductive roll having the following structure was proposed. That is, in this conductive roll, a base layer made of a conductive elastic material and having a hardness adjusted to be low by containing a softening agent is provided on the outer peripheral surface of the shaft body having conductivity, and the outer periphery thereof is further provided. On the surface, a softening agent migration-preventing layer made of a predetermined conductive resin, which prevents migration of constituent components such as a softening agent contained in the base layer to the roll surface, and a volume resistivity adjusted within a predetermined range. A resistance adjusting layer made of semi-conductive rubber and a protective layer made of semi-conductive resin, which prevents adhesion of the roll surface to the photoreceptor due to long-term pressure contact, are sequentially coated and formed. All of the required characteristics (a) to (d) described above can be effectively realized by the existence of the respective layers.

By the way, among the above-mentioned conductive rolls, particularly the charging roll and the developing roll, in order to reduce the driving torque for the rotation of the roll and in order to uniformly charge the surface of the photoreceptor, or In order to form a good toner image by uniformly adhering the toner to the surface, a better contact with the photosensitive material is required, and from this point, the hardness (Hs: JIS) of the base layer that influences such characteristics is required. A) is adjusted to an ultra-low hardness of 20 degrees or less,
Is desired.

Therefore, in the conductive roll disclosed in the above publication, when used as a charging roll or a developing roll, a large amount of a softening agent is added to the conductive elastic material constituting the base layer. By being compounded, the ultra-low hardness can be achieved.

However, in such a conductive roll, it is unavoidable that the compression set also increases as the content of the softening agent in the base layer increases. Therefore, in such a conventional conductive roll, in the case where a large amount of the softening agent is contained in the base layer, the contact portion with the photoreceptor is distorted by long-term pressure contact with the photoreceptor. Deformation remains, which lowers the contact property of the photosensitive material, and as a result, so-called image unevenness may occur, which causes white spots in the image.

In order to reduce the hardness of the base layer without increasing the blending amount of the softening agent, such a base layer is
It is conceivable to use a foamable elastic material having electrical conductivity, which would not only impair the smoothness of the roll surface due to the presence of air bubbles on the surface of the base layer, but would also increase the amount of gold in the manufacturing process. Foaming work using a mold is forced, and it imposes a great load on both the equipment side and the working side.
It is not a realistic measure.

[0009]

Here, the present invention has been made in view of the above-described circumstances, and the problem to be solved is that the compression set is not increased at all and an ultra-low hardness is achieved. It is to provide a conductive roll that can be effectively realized.

[0010]

SOLUTION: As a result of various studies by the present inventors in order to solve the above problems, a softening agent in a cured product (polyurethane rubber) obtained by reacting a specific polyol and polyisocyanate It has been found that when the hardness is adjusted so as to be remarkably lowered by containing a large amount of, the increase in compression set can be suppressed extremely effectively.

That is, the present invention has been completed on the basis of such findings, and the features thereof are as follows.
On the outer peripheral surface of the shaft body, a base layer made of a conductive elastic body is provided, and in a conductive roll having a conductive coat layer provided on the outer peripheral surface of the base layer, the base layer is
It is composed of a reaction-cured product of a polyolefin polyol having both end hydroxyl groups and a polyisocyanate, and contains a petroleum softener at a ratio of 80 parts by weight or more relative to 100 parts by weight of the both end hydroxyl group containing polyolefin polyol. However, the hardness (Hs: JIS A) is set to 20 degrees or less.

According to a preferred embodiment of the conductive roll according to the present invention, the base layer contains an ionic conductive agent and / or an electronic conductive agent and has a volume resistivity of 10 ⁸ Ωcm or less. It

According to one of the advantageous aspects of the present invention, the petroleum-based softener is composed of paraffinic oil.

Furthermore, according to one of the preferred embodiments of the present invention, the protective layer is formed of a composition in which N-methoxymethylated nylon is mixed with an ionic conductive agent and / or an electronic conductive agent. It is composed of layers.

Furthermore, according to one of the preferred embodiments of the present invention, the coat layer comprises a resistance adjusting layer provided on the base layer and a protective layer formed on the resistance adjusting layer. In addition, the resistance adjusting layer, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, a composition mainly composed of any one of acrylic rubber and an ion conductive agent, or epichlorohydrin rubber, nitrile It is formed by using a composition containing any one of rubber, hydrogenated nitrile rubber and acrylic rubber, an epichlorohydrin-ethylene oxide copolymer rubber and an ion conductive agent as a main component, and the protective layer is N-methoxymethyl. It is formed from a composition in which an ionic conductive agent and / or an electronic conductive agent is blended with a synthetic nylon.

According to one of the advantageous aspects of the present invention, a softening agent migration preventing layer, a resistance adjusting layer, and a protective layer, in which the coating layers are sequentially laminated from the inner side to the outer side in the roll radial direction. And the softening agent migration-preventing layer is formed of a composition obtained by blending N-methoxymethylated nylon with an electronic conductive agent, and the resistance adjusting layer is formed of epichlorohydrin-ethylene oxide copolymer rubber. , Epichlorohydrin rubber, hydrogenated nitrile rubber, a composition mainly containing any one of acrylic rubber and an ion conductive agent, or any one of epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, acrylic rubber It is formed by using a composition mainly composed of epichlorohydrin-ethylene oxide copolymer rubber and an ionic conductive agent, But it will be formed from composition comprising brought blended N- methoxy ionic conductive agent to the methylated nylon and / or electron conductive agent.

Further, according to one of preferred embodiments of the present invention, the coating layer is any one of a polyurethane-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, and a polyester-based thermoplastic elastomer, which are crosslinked with an amino resin. It is composed of a protective layer formed of a composition containing one type or any one of a fluorine-based rubber, a fluorine-based resin, and a silicon rubber and an electronic conductive agent.

Furthermore, according to one of the preferred embodiments of the present invention, the coating layer is a softening agent migration-preventing layer provided on the base layer, and a protective layer formed on the softening agent migration-preventing layer. And a softener migration-preventing layer,
A polyurethane-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, or a polyester-based thermoplastic resin, which is formed of a composition obtained by blending N-methoxymethylated nylon with an electronic conductive agent, and further has the protective layer crosslinked with an amino resin. The composition is mainly composed of any one of the elastomers, or any one of the fluorine-based rubber, the fluorine-based resin, and the silicon rubber, and the electronic conductive agent.

[0019]

As described above, in the conductive roll according to the present invention, the base layer provided on the outer peripheral surface of the shaft body is made of a conductive elastic body, and particularly this conductive elastic body has hydroxyl groups at both ends. Since it is composed of a reaction-cured product of a contained polyolefin-based polyol and a polyisocyanate, an increase in compression set due to an increase in the content of the softening agent can be effectively suppressed, and further, such a cured product. Contains a petroleum-based softening agent in a proportion of 80 parts by weight or more based on 100 parts by weight of a polyolefin polyol containing hydroxyl groups at both ends, and has a hardness (Hs: JIS A) of 20 degrees or less. Ultra-low hardness can be advantageously achieved.

Therefore, in the conductive roll according to the present invention, the compression set is not increased at all,
The ultra-low hardness can be effectively realized, and thereby the contact property of the photosensitive material can be more effectively enhanced. Therefore, when used as a charging roll or a developing roll, the reliability of charging performance and toner adhesion can be improved. Not only can the properties be improved, but also the occurrence of image unevenness and the like due to residual strain at the contact portion with the photoconductor can be very effectively prevented.

Further, in such a conductive roll, when the base layer contains an ionic conductive agent or an electronic conductive agent and has a volume resistivity of 10 ⁸ Ωcm or less, it is advantageous to make the electric characteristics uniform. The advantage that it can be achieved will be obtained.

Further, in such a conductive roll, when the petroleum-based softening agent contained in the base layer is composed of paraffinic oil, the paraffinic oil has a very good phase with respect to the olefinic synthetic rubber. Since it has solubility, a large amount can be added to the base layer composed of a reaction-cured product of a polyolefin polyol having both terminal hydroxyl groups and a polyisocyanate, and migration of the softening agent from the base layer to the roll surface is possible. This can be effectively avoided or suppressed, and thus the contamination of the photosensitive material can be effectively reduced.

Furthermore, in such a conductive roll,
The coating layer provided on the outer peripheral surface of such a base layer is N
-When it is composed of a conductive protective layer formed of a composition prepared by mixing ionic methyl-containing nylon with an ionic conductive agent and / or an electronic conductive agent, it is fixed to a photoreceptor that is pressed or brought into contact ( Adhesion) can be advantageously prevented.

In the electroconductive roll, the coat layer is composed of a resistance adjusting layer provided on the base layer and a protective layer formed on the resistance adjusting layer, and the resistance adjusting layer is provided. However, epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, a composition mainly composed of any one of acrylic rubber and an ion conductive agent, or epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, It is formed by using a composition mainly containing any one of acrylic rubber, epichlorohydrin-ethylene oxide copolymer rubber and an ionic conductive agent, and the protective layer further comprises N-methoxymethylated nylon, an ionic conductive agent and And / or when it is formed from a composition containing an electronic conductive agent,
By the protective layer, the tackiness on the roll surface can be advantageously reduced, and by the resistance adjusting layer, the electric resistance can be effectively equalized and can be effectively maintained for a long period of time. Therefore, excellent withstand voltage (leakage resistance) can be stably ensured for a longer period of time.

Further, in such a conductive roll, the coat layer is composed of a softening agent migration prevention layer, a resistance adjusting layer and a protective layer which are sequentially laminated from the inner side to the outer side in the roll radial direction. The softener migration prevention layer,
It is formed from a composition obtained by blending N-methoxymethylated nylon with an electronic conductive agent, and the resistance adjusting layer is one of epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, and acrylic rubber. A composition containing any one of them and an ion conductive agent as a main component, or any one of epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, and acrylic rubber, and an epichlorohydrin-ethylene oxide copolymer rubber and an ion conductive agent as a main component When the protective layer is formed from a composition prepared by mixing N-methoxymethylated nylon with an ionic conductive agent and / or an electronic conductive agent, the protective layer is With the resistance adjustment layer, it is possible to effectively reduce the adhesiveness and ensure excellent withstand voltage for a long time. By such a softening agent migration prevention layer, a barrier effect of preventing migration of the softening agent or the like from the inside of the base layer to the roll surface can be advantageously exhibited, and the occurrence of the bleeding phenomenon can be effectively prevented, and thus the photoreceptor Contamination can be effectively prevented.

Furthermore, in such a conductive roll,
The coating layer is any one of a polyurethane-based thermoplastic elastomer crosslinked with an amino resin, a polyamide-based thermoplastic elastomer, a polyester-based thermoplastic elastomer, or a fluorine-based rubber, a fluorine-based resin, or a silicone rubber. When it is composed of a protective layer formed of a composition mainly containing one of them and an electronic conductive agent, properties such as low friction coefficient and non-adhesiveness of those elastomers, synthetic rubbers and synthetic resins By this, sticking (adhesion) to the photoconductor can be favorably prevented, and adhesion of toner to the roll surface can be effectively reduced.

In the electroconductive roll, the coat layer is composed of a softening agent migration preventing layer provided on the base layer and a protective layer formed on the softening agent migration preventing layer, The softener migration-preventing layer is formed of a composition obtained by blending N-methoxymethylated nylon with an electronic conductive agent, and the protective layer is further crosslinked with an amino resin, a thermoplastic polyurethane elastomer, or a polyamide-based thermoplastic elastomer. In the case of being formed of a composition containing any one of a thermoplastic elastomer and a polyester-based thermoplastic elastomer, or any one of a fluorine-based rubber, a fluorine-based resin, and a silicone rubber and an electronic conductive agent In addition, the protective layer can effectively prevent or suppress the adhesion to the photoreceptor and the adhesion of the toner to the roll surface, and the softener migration prevention layer. Therefore, prevention of contamination of the photosensitive member due to the migration of such softening agent from the internal base layer is of so that the can be effectively achieved.

[0028]

Specific Structure By the way, FIG. 1 shows an example of a conductive roll having a structure according to the present invention. As is clear from this figure, the conductive roll 10 is made of metal, and the base layer 14 having a predetermined thickness is provided on the outer peripheral surface of the conductive shaft body 12, and the outer peripheral surface of the base layer 14 is provided. The softening agent migration prevention layer 16, the resistance adjusting layer 18, and the protective layer 20 are coated in this order from the inside to the above.
It is formed and formed with a predetermined thickness.

More specifically, the base layer 14 is made of a conductive elastic material. Then, as an elastic material which gives this conductive elastic body, a composition comprising a reaction-cured product (polyurethane rubber) of a polyolefin polyol having both terminal hydroxyl groups and a polyisocyanate is used. In addition,
Examples of the polyolefin polyol containing hydroxyl groups at both ends include, for example, hydroxyl groups as functional groups at both ends,
In liquid polyisoprene, liquid polybutadiene, and copolymers thereof, those obtained by hydrogenating some or all of the double bonds to form olefins are used, and among them, in general, the molecular weight thereof is used. Is 1000-4
000 is preferably used, and usually 250
The thing of about 0 will be used. On the other hand, examples of the polyisocyanate include tolylene diisocyanate (TDI), 4,4 ′ diphenylmethane diisocyanate (MDI), and xylylene diisocyanate (XD).
I), metaxylylene diisocyanate (MXDI),
Hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), hydrogenated TDI, hydrogenated MD
I, hydrogenated XDI, isophorone diisocyanate (IP
DI), trimethylhexamethylene diisocyanate (TMDI), dimer acid diisocyanate (DDI)
Etc., any of those conventionally known can be used, but among them, in terms of the curing rate and processability of the cured product (polyurethane rubber) obtained by the reaction with a polyol,
IPDI is particularly preferably used.

The equivalent ratio of the polyolefin polyol containing hydroxyl groups at both ends and the polyisocyanate is preferably NCO / OH = 0.8 to 1.2, more preferably NCO / OH = 0.95. It is used within the range of about 1.1. This is because, when both of these components are used outside the above range, the resulting cured product has increased tackiness, and the base layer 1 of the conductive roll 10 is increased.
This is because the constituent material of No. 4 cannot be put to practical use.

In such a specific polyurethane rubber composition, the amount of the petroleum softening agent is 80 parts by weight or more based on 100 parts by weight of the polyolefin polyol having both hydroxyl groups at both ends. Blended with 20
It must be adjusted to provide a base layer 14 having a hardness (Hs: JISA) of less than degrees. This is because the object of the present invention can be advantageously achieved only after the ultra low hardness base layer 14 is formed using the polyurethane rubber composition containing a large amount of petroleum softener as described above. . As such a petroleum-based softening agent, for example, naphthene-based oils, aroma-based oils, paraffin-based oils, etc., which are conventionally used as rubber softening agents, can be advantageously used. Among them, paraffin oil can be used particularly preferably. Thereby, the effects as described above can be effectively enjoyed. Of course, the type of paraffin oil is not limited to any particular type.

Further, in the polyurethane rubber composition, as in the conventional case, a predetermined conductive agent is blended, and thereby the base layer 14 is given conductivity. Advantageously, as the conductive agent, an ionic conductive agent or an electronic conductive agent is used, and a predetermined amount of the conductive agent is mixed so that the volume resistivity of the base layer 14 is adjusted to 10 ⁸ Ωcm or less. Become. The type of ion conductive agent or electron conductive agent used here is not particularly limited, and any conventionally known one can be used. For example, as the ion conductive agent, an aliphatic sulfonic acid can be used. Salt, higher alcohol sulfate ester salt, higher alcohol phosphate ester salt, higher alcohol ethylene oxide addition sulfate ester salt, higher alcohol ethylene oxide addition phosphate ester salt, higher alcohol ethylene oxide, polyethylene glycol fatty acid ester, polyhydric alcohol fatty acid ester,
Betaine and the like can be used, and particularly preferably, quaternary ammonium salts such as trimethyl octadecyl ammonium perchlorate and benzyl trimethyl ammonium chloride, lithium perchlorate, potassium perchlorate and the like can be used. Further, as the electronic conductive agent, conductive metal oxides such as conductive tin oxide, conductive titanium oxide and conductive zinc oxide, carbon black and the like can be more preferably used.

The polyurethane rubber composition further contains various conventionally known compounding agents and additives.
If necessary, they may be added and mixed in the usual mixing ratio.

On the other hand, the softener migration preventing layer 16 provided on the outer peripheral surface of the base layer 14 as described above can be formed of a conventionally used material, but is preferably N.
It is formed of a resin composition in which an electron conductive agent is mixed with methoxymethylated nylon. In addition,
In such a resin composition, a conventionally known one is used as the N-methoxymethylated nylon as the main component, and a known one as described above is also used as the electronic conductive agent to form them. The softening agent migration prevention layer 16 is compounded in such an amount that the volume resistivity can be adjusted to about 10 ² to 10 ⁷ Ωcm. Further, the resin composition as the material for forming the softening agent migration prevention layer 16 is appropriately compounded with various compounding agents generally used.

The resistance adjusting layer 18 may be formed of a conventionally used material, but is preferably any one of epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin rubber, hydrogenated nitrile rubber and acrylic rubber. In one of them, a rubber composition containing an ion conductive agent, or a mixture of epichlorohydrin-ethylene oxide copolymer rubber with any one of epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, and acrylic rubber. A rubber composition containing an ion conductive agent is formed. As the ionic conductive agent used here, the known one as described above is used, and the volume resistivity of the resistance adjusting layer 18 to be formed is 10 ⁷ to 10 ¹⁰ Ωcm, preferably about 10 ⁸ Ωcm. It is compounded in various synthetic rubbers as described above in an adjustable amount. Also, in the rubber composition that provides such a resistance adjusting layer 18, various compounding agents such as a vulcanizing agent and the like which have been conventionally known, additives, and the like can be compounded at a normal ratio, if necessary. Become.

Further, the protective layer 20 is advantageously formed of a resin composition containing N-methoxymethylated nylon as a main component, which is similar to the material for forming the softener migration preventing layer 16. However, in this resin composition, not only the electronic conductive agent as described above but also an ionic conductive agent can be used as the conductive agent. That is, an electron conductive agent and an ionic conductive agent may be used alone or in combination with such a resin composition, and they are preferably used in the protective layer 20 formed. Is mixed in such an amount that the volume resistivity can be adjusted to about 10 ⁷ to 10 ¹⁰ Ωcm. In addition,
The ionic conductive agent used here is not particularly limited, and any known one as described above can be used.
In addition, in the resin composition that provides this protective layer 20,
It goes without saying that various commonly used compounding agents and the like can be appropriately compounded.

In the conductive roll 10 having such a constitution, the hardness of the base layer 14 (Hs: JIS
In the case where A) is adjusted to 10 degrees or less, the contact property of the photosensitive material can be further improved, and the charging performance for the photoconductor can be further effectively enhanced.
It can be used particularly preferably. Further, in the conductive roll 10, the softening agent migration preventing layer 16, the resistance adjusting layer 18, and the protective layer 20 are laminated and formed on the outer peripheral surface of the base layer 14 in this order from the inside. However, the resistance adjusting layer 18 and the protective layer 20 are formed on the outer peripheral surface of the base layer 14 without forming the softener migration preventing layer 16.
They may be sequentially laminated and formed, or only the first protective layer 20 may be directly formed on the outer peripheral surface of the base layer 14. Even by this, the excellent effects of the present invention as described above can be effectively exhibited.

By the way, the conductive roll 10 as shown in FIG. 1 is advantageously manufactured as follows.

That is, first, a polyolefin-based polyol having hydroxyl groups at both ends, a petroleum-based softening agent, and a conductive agent are mixed, and further, various compounding agents are mixed as necessary to obtain a mixed solution, A predetermined polyisocyanate is added to the thus-obtained mixed solution, mixed, and then degassed in vacuum to form a base layer mainly composed of a polyolefin polyol having both terminal hydroxyl groups and a polyisocyanate which are materials for forming the base layer 14. Obtain the composition. As a conductive agent,
When using a particulate form of carbon black or the like, in addition to the usual mixing operation when obtaining the mixed solution,
It is desirable to perform a kneading operation such as roll kneading so that the particulate conductive agent can be favorably dispersed in the mixed liquid. Further, the addition of polyisocyanate to such a mixed liquid is preferably carried out immediately before injecting the composition thus obtained into a cylindrical mold described later.

Next, after the shaft body 12 to which a conductive adhesive has been applied in advance on the outer peripheral surface and which has been subjected to the adhesion treatment is placed in the molding cavity of the cylindrical mold having the same structure as the conventional one, Then, the composition for forming a base layer obtained as described above is injected into the molding cavity. Then, this is heated and the composition for forming a base layer is cured by reaction to obtain a base roll in which the base layer 14 is integrally formed on the outer peripheral surface of the shaft body 12. In the curing operation of the composition for forming a base layer by heating, the conditions such as curing temperature and time are not particularly limited, but generally, it is 3 at 80 ° C.
Time, or 0.5 hours at 100 ° C or higher.
A cure time of 8 hours is required.

After the production of such a base roll or prior to the production of the base roll, a coating solution for providing the softening agent migration prevention layer 16, the resistance adjusting layer 18, and the protective layer 20 is formed by using the above-mentioned forming material. As before,
Prepare each. Then, using the coating liquid and the base roll, the above three layers are sequentially laminated and formed on the outer peripheral surface of the base layer 14 by a known coating method such as dipping. As a result, the target conductive roll 10 is obtained.

Although the thickness of each layer of the conductive roll 10 is appropriately determined depending on its use, etc., the base layer 14 is usually formed to have a thickness of about 2 to 6 mm to prevent the softener migration. The layer 16 is formed with a thickness of about 1 to 10 μm. The resistance adjustment layer 18 has a thickness of 20 to 200 μm.
The protective layer 20 is formed to a thickness of about 1 to 20 μm. When embodied as a charging roll, for example, the base layer 14 has a thickness of about 3 mm, the softening agent migration prevention layer 16 has a thickness of about 5 μm, and the resistance adjusting layer 18 has a thickness of about 100 μm. The layers 20 are each formed with a thickness of about 10 μm.

Next, FIG. 2 shows another example of the conductive roll according to the present invention. In FIG. 2, the conductive roll 22 is made of metal, a base layer 26 having a predetermined thickness is provided on the outer peripheral surface of a conductive shaft body 24, and a softening agent is provided on the outer peripheral surface of the base layer 26. The migration prevention layer 28 and the protective layer 30 are sequentially formed by coating so as to have a predetermined thickness.

The base layer 26 and the softening agent migration prevention layer 28 constituting the conductive roll 22 are made of the same material as the base layer 14 and the softening agent migration prevention layer 16 of the conductive roll 10. On the other hand, the protective layer 30 includes a polyurethane-based thermoplastic elastomer (TPU) and a polyamide-based thermoplastic elastomer (TP) cross-linked with an amino resin.
EA), polyester-based thermoplastic elastomer (TPE
It is formed of a composition in which an electronic conductive agent is mixed with any one of E), or any one of fluororubber, fluororesin, and silicone rubber.

More specifically, as the above-mentioned elastomer, synthetic rubber, and synthetic resin, which are the main components of the composition that provides the protective layer 30, any of various known ones can be used. For example, as TPU and TPEE, various types such as ether type and ester type are used, as TPEA, N-methoxymethylated nylon and the like, and as fluorine type rubber, various types of fluororubber thermoplastic elastomer and liquid fluororubber. Etc. can be used. Further, PVDF or the like may be used as the fluorine-based resin, and liquid silicone rubber or the like may be used as the silicone rubber. Also,
Even if it is an amino resin used for cross-linking each elastomer, that is, TPU, TPEA, TPEE, etc., it is not particularly limited, and any of urea resin, melamine resin, benzoguanamine resin, etc. is appropriately selected and used. To get. In addition, those amino resins are used as the protective layer 3 obtained.
From the viewpoint of ensuring a flexibility of 0, it is desirable to mix the elastomer in an amount of about 1 to 20% by weight.

On the other hand, as the electronic conductive agent blended with such various main components, the known ones as described above can be used. The volume ratio of the protective layer 30 formed is preferably 10 ² to 10 ¹¹ Ωcm,
More preferably, the amount can be adjusted to about 10 ⁵ to 10 ⁹ . Further, it does not matter even if various compounding agents such as vulcanizing agents and fillers which are generally used are added to the composition.

The conductive roll 22 having such a structure
In this case, since the base layer 26 has the same structure as the base layer 14 of the conductive roll 10, the excellent effects of the present invention as described above can be effectively enjoyed, and the protective layer 30 is also provided. The presence of the toner makes it possible to effectively prevent the toner from adhering, and to effectively exhibit the stable toner charging property for a longer period of time, and thus it can be particularly preferably used as a developing roll. . Further, in the conductive roll 22, the softener migration preventing layer 28 and the protective layer 30 were sequentially laminated on the outer peripheral surface of the base layer 26, but on the outer peripheral surface of the base layer 26,
It is also possible to directly form only the protective layer 30. With this, the same effect as described above can be obtained.

And, such a conductive roll 22 is also
Other than preparing a coating solution for providing the softening agent migration prevention layer 28 and a coating solution for forming the protective layer 30,
The conductive roll 10 can be advantageously manufactured in the same manner as in the manufacturing method.

The thickness of each layer of the conductive roll 22 is not particularly limited, but is usually the base layer 26.
The softening agent migration prevention layer 28 is formed to have the same thickness as the base layer 14 and the softening agent migration prevention layer 16 of the conductive roll 10, and the protective layer 30 is formed to a thickness of about 1 to 20 μm. Become. Then, for example, this conductive roll 22
When the material is used as a developing roll, the base layer 26 is 5
The softener migration prevention layer 28 is formed to a thickness of about 5 mm, and the protective layer 20 is formed to a thickness of about 10 μm.

[0050]

EXAMPLES Some examples of the present invention will be shown below to clarify the present invention in more detail. However, the present invention is not limited by the description of such examples. Needless to say, it is not something to receive. Further, in addition to the following specific examples, in addition to the following embodiments, the present invention includes various modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
It should be understood that modifications, improvements, etc. may be made.

Examples 1 to 4 First, as a polyolefin polyol having hydroxyl groups at both ends, a liquid polyol having a molecular weight (Mn) of 2500, which has hydroxyl groups at both ends and is olefinized by hydrogenating almost all double bonds. Isoprene was prepared, paraffinic process oil was used as a petroleum softener, and Ketjen black and a quaternary ammonium salt (tetramethylammonium chloride) were used as conductive agents in predetermined amounts. Then, they are mixed by stirring in the proportions shown in Table 1 below, and in the case where Ketjen black is used as the conductive agent, three roll kneading is performed together with such Ketjen black to eliminate Ketjen black aggregation. Up to the above, three kinds of mixed liquids having different contents of the softening agent and the conductive agent to be blended were obtained. Then, IPDI as polyisocyanate was added to the thus obtained three kinds of mixed liquids in an equivalent ratio of NCO / OH = 1.05.
The following amounts were added, and these were again mixed with stirring, and then degassed under vacuum to prepare three types of compositions that give a base layer.

Next, the three kinds of base layer-forming compositions thus obtained were each provided with a plurality of cylindrical gold-made members having shafts (diameter: 10 mm) whose surfaces were previously treated with a conductive adhesive. Inject each separately into the mold cavity and then place each cylindrical mold in the oven to
Heat treatment was carried out at 20 ° C. for 30 minutes to cure each of the base layer forming compositions. Thus, on the outer peripheral surface of the shaft body, 5
Three types of base rolls 1 to 3 each having a thickness of mm and formed with different types of base layers were obtained. And those 3
After taking out the respective types of base rolls 1 to 3 from the mold, the hardness of each base layer (Hs: JIS
A) and volume resistivity were measured. The results are shown in Table 1 below.
Are also shown.

[0053]

[Table 1]

Next, a composition for providing each of the softening agent migration prevention layer, the protective layer, and the resistance adjusting layer was prepared according to the following formulation.
It was adjusted. That is, the composition that provides the softener migration prevention layer,
The composition for providing a protective layer by blending 15 parts by weight of carbon black with respect to 100 parts by weight of N-methoxylmethylated nylon is 100% by weight of N-methoxylmethylated nylon. Each was prepared by blending 8 parts by weight of black. Further, the composition for providing the resistance adjusting layer is such that 5 parts by weight of Pb ₃ O ₄ and 1.25 parts of ethylenethiourea are added to 100 parts by weight of the epichlorohydrin-ethylene oxide copolymer.
2 parts by weight, 1 part by weight of a processing aid, 40 parts by weight of a hard clay, and 0.2 parts by weight of a quaternary ammonium salt (tetramethylammonium chloride) were added to each to prepare a mixture. Then, each composition thus obtained was dissolved in methyl ethyl ketone to prepare a coating liquid having a predetermined viscosity for providing each of the above layers.

Thereafter, each of the coating liquids thus prepared was used to dip the previously obtained 3 by a dipping method.
On the outer peripheral surface of each of the types of base rolls 1 to 3, a softening agent migration prevention layer having a thickness of 5 μm and a volume resistivity of 10 ³ Ωcm, and a resistance adjusting layer having a thickness of 100 μm and a volume resistivity of 10 ⁸ Ωcm, respectively. , A protective layer having a thickness of 10 μm and a volume resistivity of 10 ⁹ Ωcm was sequentially laminated and formed to obtain three kinds of conductive rolls each having a different base layer, and the outer peripheral surface of the base roll 1 was softened. A conductive roll was obtained in which the resistance adjusting layer and the protective layer were laminated and formed in the above thickness without forming the agent migration prevention layer. Then, among these four types of conductive rolls, those in which the three layers are formed on the outer peripheral surfaces of the base rolls 1 to 3 are referred to as Examples 1 to 3, and the outer peripheral surface of the base roll 1 is described above. Example 4 has two layers.

Examples 5 to 14 First, the same amounts as those used as the constituent components of the composition for providing the base layer in the above Examples 1 to 4 were prepared in predetermined amounts, and then, the above Examples 1 to 4 were prepared. In the same manner, mix them in the proportions shown in Table 2 below,
Three types of compositions for forming a base layer having different contents of the softening agent and the conductive agent mixed therein were prepared.

Subsequently, the three kinds of base layer-forming compositions thus prepared and a plurality of shafts (diameter: 10 mm) were used to carry out the same procedure as in Examples 1 to 4 on the outer peripheral surface of the shafts. Then, base rolls 4 to 6 having base layers of different types were formed. Then, the hardness (Hs: JIS A) and volume resistivity of each base layer in these three types of base rolls 4 to 6 were measured according to the conventional method. The results are also shown in Table 2 below.

[0058]

[Table 2]

Next, compositions for providing the softener migration-preventing layer were prepared in the same manner as in Examples 1 to 4 above, and thereafter,
This was dissolved in a mixed solvent of water and methanol to prepare a coating liquid for forming a softener migration preventing layer. on the other hand,
Apart from that, as a composition for providing a protective layer, the following Table 3
And, 6 types were obtained according to the blending ratio (weight basis) shown in Table 4 and so that the protective layer to be formed had the volume resistivity as shown in Tables 3 and 4. And these 6 types of compositions for protective layer formation were made into compositions A-F for protective layer formation, respectively. Thereafter, the protective layer forming compositions A to E were dissolved in methyl ethyl ketone, and the protective layer forming composition F was dissolved in toluene to prepare 6 types of coating liquids for forming a protective layer.

[0060]

[Table 3]

[0061]

[Table 4]

Then, the six kinds of coating liquids containing the protective layer forming compositions A to F thus obtained and the coating liquid for forming the softening agent migration preventing layer were used to obtain the above by a dipping method. Base roll 4-6
Nine kinds of conductive rolls were obtained by sequentially laminating and forming a softening agent migration prevention layer and a protective layer on the outer peripheral surface of the above, respectively, or by forming only the protective layer. It was
That is, a softening agent migration prevention layer and a protective layer made of the protective layer-forming composition A are respectively formed on the outer peripheral surfaces of the base rolls 4 to 6 to obtain three types of conductive rolls, and these are carried out. It was set as Examples 5-7. Further, a conductive roll having only the protective layer of the composition A formed on the outer peripheral surface of the base roll 4 was obtained, and this was set as Example 8. Further, on the outer peripheral surface of the base roll 4, a softening agent migration prevention layer and a protective layer comprising the protective layer forming compositions B to F were respectively formed to obtain 5 types of conductive rolls, and these were used as examples. 9-13
And The thickness of the softening agent migration prevention layer is 5 μm,
The thickness of the protective layer was 10 μm.

Comparative Examples 1 to 3 First, a predetermined amount of polynorbornene rubber, Ketjen black and naphthenic oil were prepared. Then, they were mixed in the proportions shown in Table 5 below, and a predetermined mixing operation was carried out to prepare two types of compositions having different blending amounts of the softening agent and giving a base layer. Subsequently, the two kinds of compositions for forming a base layer thus prepared and a shaft (diameter: 10 m
m) and in the same manner as in Examples 1 to 4, base rolls 7 and 8 having base layers of different types formed on the outer peripheral surface of the shaft body were obtained. Then, the hardness (Hs: JIS A) and the volume resistivity of each base layer in these two types of base rolls 7 and 8 were measured according to the conventional method. The results are also shown in Table 5 below.
The thickness of the base layer of these two types of base rolls 7 and 8 was the same as that in Examples 1 to 4.

[0064]

[Table 5]

Then, in the same manner as in Examples 1 to 4,
The coating liquid for forming each layer of the softening agent migration prevention layer, the resistance adjusting layer, and the protective layer was prepared, and further, by using the dipping method, the outer periphery of the base roll 7 and the base roll 8 obtained as described above. On the surface, the above three layers are sequentially laminated and molded to obtain two kinds of conductive rolls having different base layer forming materials from those of Examples 1 to 4, and resistance is provided on the outer peripheral surface of the base roll 7. A conductive roll formed by laminating the adjustment layer and the first protective layer was obtained. Then, among these three kinds of conductive rolls, those in which the three layers are formed on the outer peripheral surfaces of the base rolls 7 and 8 are Comparative Examples 1 and 2, and the outer peripheral surface of the base roll 7 is Two
Comparative Example 3 was one in which two layers were formed. In addition,
The thickness of each layer was the same as in Examples 1 to 4 above.

Then, using 16 kinds of conductive rolls thus obtained (Examples 1 to 13 and Comparative Examples 1 to 3),
According to JIS K 6301, hardness (Hs: JIS
A) and compression set (70 ° C., 22 hours, 25% compression) were measured, and various performance evaluations were performed as follows, and the results are shown in Tables 6 and 7 below. It was

-Driving Torque- Each conductive roll is pressed against the fixed photoconductor with a pressure such that the contact portion is dented by 1 mm in the radial direction, and under such a condition, each roll is driven by a torque motor. It was rotated and the current value at the beginning of its movement was measured. Then, the obtained measured value is converted into torque, and the calculated value is 3
When it was less than kgf · cm, it was evaluated as ◯, and when it was less than 3 kgf / cm, it was evaluated as x.

-Image unevenness-Each conductive roll is attached to a laser printer [LP1060-
SP3: manufactured by Ricoh Co., Ltd.], the image was displayed, and the obtained image was observed. When there was no image unevenness, it was evaluated as ◯, and when there was it, it was evaluated as x.

-Sensitivity of Sensitive Material- Each conductive roll was loaded with a load of 500 g on the shafts at both ends, and a new photoconductor was pressed against the conductive roll for 1 month under a temperature and humidity environment of 45 ° C x 90%. I left it. After that, the photoreceptor was observed, and when no trace of the roll was observed, it was evaluated as ◯, and when it was observed, it was evaluated as x.

[0070]

[Table 6]

[0071]

[Table 7]

As is clear from the results of Tables 6 and 7, when Examples 1 to 13 and Comparative Examples 1 to 3 are compared,
Although hardness is configured to be extremely low, Examples 1 to 13 show much smaller values than Comparative Examples 1 to 3 in compression set, and Comparative Example 1
3 to 3, image unevenness is generated, whereas in Example 1
In Nos. 13 to 13, no such image unevenness occurred. This is because the conductive roll according to the present invention has both ultra-low hardness and low compression set, whereby excellent roll performance that could not be realized at all in the conventional one can be exhibited. It clearly shows that Furthermore, Examples 1 to 13 were found to be superior to Comparative Examples 1 to 3 in terms of stain-sensitive material sensitivity, which is contained in the conductive roll according to the present invention, particularly in the base layer. It has been shown that by using paraffinic oil as a petroleum-based softening agent, excellent sensitive material stain resistance can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory longitudinal sectional view showing an example of a conductive roll according to the present invention.

FIG. 2 shows another example of a conductive roll according to the present invention.
It is a figure corresponding to.

FIG. 3 is an explanatory view schematically showing the structure of an electrophotographic copying machine.

[Explanation of symbols]

 10,22 Conductive roll 12,24 Shaft body 14,26 Base layer 16,28 Softener migration prevention layer 18 Resistance adjustment layer 20,30 Protective layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // B29K 21:00 B29L 31:34

Claims (8)

[Claims] 1. A conductive roll having a base layer made of a conductive elastic material provided on the outer peripheral surface of a shaft body, and a conductive coating layer provided on the outer peripheral surface of the base layer. The base layer is composed of a reaction-cured product of a polyolefin polyol having both end hydroxyl groups and a polyisocyanate, and a petroleum softening agent is used in an amount of 80 parts by weight or more based on 100 parts by weight of the both end hydroxyl group containing polyolefin polyol. Included in proportion, hardness (Hs: JIS A) is 2
A conductive roll characterized by being set to 0 degrees or less. 2. The conductive roll according to claim 1, wherein the base layer contains an ionic conductive agent and / or an electronic conductive agent and has a volume resistivity of 10 ⁸ Ωcm or less. 3. The conductive roll according to claim 1, wherein the petroleum-based softening agent is paraffin-based oil. 4. The protective layer formed of a composition obtained by mixing N-methoxymethylated nylon with an ionic conductive agent and / or an electronic conductive agent, as the coating layer. 3. The conductive roll according to any one of 3. 5. The coating layer is composed of a resistance adjusting layer provided on the base layer and a protective layer formed on the resistance adjusting layer, and the resistance adjusting layer is made of epichlorohydrin-ethylene. Oxide copolymer rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, a composition mainly composed of any one of acrylic rubber and an ion conductive agent,
Alternatively, epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, any one of acrylic rubber and epichlorohydrin-formed by using a composition mainly composed of an ethylene oxide copolymer rubber and an ion conductive agent, the protective layer further The conductive roll according to any one of claims 1 to 3, which is formed of a composition obtained by blending N, N-methoxymethylated nylon with an ionic conductive agent and / or an electronic conductive agent. 6. The softening agent migration preventing layer, wherein the coating layer comprises a softening agent migration preventing layer, a resistance adjusting layer and a protective layer, which are sequentially laminated from the inner side to the outer side in the roll radial direction. Is formed from a composition obtained by blending N-methoxymethylated nylon with an electronic conductive agent, and the resistance adjusting layer is formed of epichlorohydrin-ethylene oxide copolymer rubber, epichlorohydrin rubber, hydrogenated nitrile rubber, or acrylic rubber. A composition mainly containing any one of them and an ion conductive agent, or epichlorohydrin rubber, nitrile rubber, hydrogenated nitrile rubber, any one of acrylic rubber and epichlorohydrin-ethylene oxide copolymer rubber and an ion conductive agent And a protective layer formed of N-methoxymethylated nylon. 2. A composition formed by mixing an ionic conductive agent and / or an electronic conductive agent.
4. The conductive roll according to any one of 1 to 3. 7. The coating layer is any one of a polyurethane-based thermoplastic elastomer, a polyamide-based thermoplastic elastomer, and a polyester-based thermoplastic elastomer cross-linked with an amino resin, or a fluorine-based rubber, a fluorine-based resin, or silicone. The conductive roll according to any one of claims 1 to 3, which is constituted by a protective layer formed of a composition mainly containing any one of rubber and an electronic conductive agent. 8. The softening agent migration preventive layer, wherein the coating layer is composed of a softening agent migration preventing layer provided on the base layer and a protective layer formed on the softening agent migration preventing layer. The layer is formed of a composition obtained by blending N-methoxymethylated nylon with an electronic conductive agent, and the protective layer is further crosslinked with an amino resin, a thermoplastic polyurethane elastomer, a thermoplastic polyamide elastomer, or a polyester. 4. A composition mainly composed of any one of thermoplastic thermoplastic elastomers, or any one of fluororubber, fluororesin, and silicone rubber, and an electronic conductive agent. The conductive roll according to any one of 1.