JP3989000B2 - Conductive member for image forming apparatus and method of manufacturing the same - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive member composed of a roller and a belt used in an image forming apparatus, and a method for manufacturing the same. The conductive polymer composition is suitable for use as a conductive member composed of a conductive belt, and the conductive polymer composition of the conductive member improves the electrical dependency on the environment, changes over time, etc., and is stable and good. A good image.

  As a method for imparting conductivity to a conductive member such as a conductive roller or a conductive belt used in an image forming apparatus, an electronic conductivity in which a conductive filler such as a metal oxide powder or carbon black is mixed in a polymer. There are a method using a polymer composition and a method using an ion conductive polymer composition such as urethane, acrylonitrile butadiene rubber (NBR), epichlorohydrin rubber and the like.

In the case of using an electroconductive polymer composition obtained by blending a conductive filler such as metal oxide powder or carbon black, the electrical conductivity is increased by a slight change in addition amount particularly in the required semiconductive region. Since the resistance value changes abruptly, the control becomes very difficult. For this reason, since the conductive filler is difficult to uniformly disperse in the polymer composition, there arises a problem that the resistance value varies in the circumferential direction and longitudinal direction of the roller and in the surface of the belt.
That is, since the current flow accompanying the movement of electrons depends on the dispersion state of each particle of the conductive filler, if the dispersion state of the particles varies, it becomes difficult to control the resistance value. The variation in resistance value in the product surface tends to increase. When there is secondary aggregation of particles, the variation is further increased. In addition, when carbon black is used, the belt becomes black, and it is difficult to visually check the belt due to toner or the like.

In addition, in the case of electronic conduction using a metal oxide, for example, when conductive zinc white is used, if the filling amount increases to reduce resistance, the belt becomes brittle. Furthermore, dispersion of particles becomes a problem, and resistance adjustment is difficult. In particular, it is difficult to adjust the resistance value to 10 ⁴ Ω · cm to 10 ¹² Ω · cm.

  The above problem not only becomes a problem for each member of each roller and the belt itself, but also causes a problem that the variation in the electric resistance value among the members becomes very large. Furthermore, the electric resistance value of the obtained conductive roller or conductive belt depends on the applied voltage and does not show a certain resistance value. In particular, when carbon black is used as the conductive filler, these tendencies appear remarkably. Such a phenomenon may make mechanical control difficult in an image forming process such as charging, developing, transferring, and fixing, and may increase the cost. In addition, when carbon is used, there is a problem that it cannot be colored freely.

In view of the above, in recent image forming apparatuses such as copying machines, printers, facsimiles and the like that require high image quality and energy saving, ion conductive rollers or ion conductive belts have been preferred. Proposals have been made.
For example, in Japanese Patent Application Laid-Open No. 10-169641, a semiconductive polymer elastic member in which a quaternary ammonium salt is added to a polymer material as a base material and the resistance value during continuous energization is defined while considering the use environment Has been proposed.

However, in the above-mentioned Japanese Patent Application Laid-Open No. 10-169641, by adding a quaternary ammonium salt having a specific anion, an increase in resistance value during continuous energization in an ion conductive roller or ion conductive belt is attempted. However, there is a problem that the environmental dependency (temperature dependency + humidity dependency) of the electrical resistance value cannot be sufficiently reduced. Furthermore, the photoreceptor may be contaminated depending on the type and presence of the salt to be blended or the blending content.
As described above, in the conductive member, it is necessary not only to reduce the increase of the resistance value during continuous energization but also to consider the environmental dependency of the electrical resistance and the problem of contamination of the photosensitive material such as salt to be mixed. There is.

  As an ionic conductive conductive agent, there are conductive oligomers and conductive plasticizers including polyether structures such as polyethylene oxide (both Mn <10000), but these are not fixed in the polymer composition, There is a problem that causes bleed and bloom. In particular, when used in conductive rollers and conductive belts for copying machines and printers, these can migrate and contaminate the photoconductor, contaminating the image, or worst, altering and destroying the photoconductor. May end up.

  In addition, in a system using a metal salt such as lithium perchlorate or an ion conductive additive salt such as various quaternary ammonium salts, the salt is dissociated depending on the blending amount and compatibility with the base polymer. Ions move toward the electrode during continuous energization, and the resistance value may increase considerably over time. In addition, added salt or the like may be deposited on the surface of the conductive member, and depending on the substance, the photoreceptor may be contaminated. In particular, when a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound is used to disperse the added salt, the salt can easily move in the polymer and the conductivity is improved. It becomes easy to precipitate. Furthermore, these low molecular weight media used also migrate to the surface, and when used for a long time, there may be a problem that transfer contamination and toner fixation occur, resulting in loss of practicality. Even in an actual image forming apparatus, these points often cause problems when used continuously for a long time.

As for the ion conductive belt, Japanese Patent Laid-Open No. 2002-304064 blends at least one thermoplastic resin and at least one hydrophilic resin which is incompatible with the thermoplastic resin. There has been proposed an endless belt (seamless belt) obtained by extrusion molding a resin composition obtained by making the viscosity of the thermoplastic resin higher than the viscosity of the hydrophilic resin at the molding temperature at the time of extrusion molding.
However, the general ion conductive belt described in the conventional publications such as the above-mentioned Japanese Patent Application Laid-Open No. 2002-304064 has a large volume resistivity environment dependency and a large increase in resistivity during continuous energization. There is a problem that sometimes. In this case, there is a problem that the transfer voltage is difficult to control, the mechanism of the image forming apparatus is complicated, a larger power source is required, the power consumption is increased, and the cost is increased.

Even in the case of ionic conduction, if a low molecular weight surfactant-like antistatic agent or the like is used, there is a risk of causing photoconductor contamination due to bleeding. Moreover, if the hygroscopicity is large, the change in electrical resistance due to a change in humidity becomes large. Furthermore, sodium perchlorate (NaClO ₄ ) and the like are difficult to handle at the time of kneading with a thermoplastic elastomer and are generally expensive.

  Furthermore, in recent years, some conductive belts are required to have flame retardancy in consideration of the usage environment. Conductive belts may be placed in high voltage and high temperature environments in image forming devices, so if the belt is flammable and flammable or has insufficient flame resistance, it may be used depending on the environmental conditions within the device. The condition may be limited. Currently provided belts are excellent in performance such as conductivity and durability and do not affect normal use, but there are still insufficient measures for flame retardancy, and there is still room for improvement.

In order to make a conductive belt made of a thermoplastic resin flame-retardant, a flame retardant is generally added. Conventionally, halogen-based flame retardants, phosphate ester-based flame retardants, and the like are added as flame retardants.
However, when the halogen-based flame retardant is added, toxic gas such as dioxin may be generated when the belt is exposed to high temperature during disposal after use. In addition, when the above-mentioned phosphate ester-based flame retardant is added, if the belt is used at a high temperature for a long period of time, the flame retardant oozes out from the inside of the belt with time and the photoreceptor May contaminate.

As described above, the provision of flame retardancy is a high priority requirement for conveyance belts, transfer belts, intermediate transfer belts, fixing belts, development belts, and photoreceptor substrate belts used in image forming apparatuses and the like. Yes. In particular, when imparting flame retardancy to a conductive belt, it is desired that non-halogen has a small impact on the environment and is non-staining when used.
Japanese Patent Laid-Open No. 10-169641 JP 2002-304064 A

The present invention has been made in view of the above-described problems, and maintains environmental resistance (temperature dependence) of electrical resistance while maintaining a sufficiently low resistance value as a conductive member composed of a roller, a belt, or the like for an image forming apparatus. + Humidity dependency) and a conductive member for an image forming apparatus with a small increase in resistance during continuous energization, as well as good electrical characteristics, low power consumption, and good and uniform images for a long time It is an object of the present invention to provide an image forming apparatus that can be obtained over a wide range.
Furthermore, the conductive belt has excellent flame retardancy without affecting other properties such as conductivity, has a small increase in resistance during continuous energization, and has variations in resistance in the belt surface. The problem is to provide a flame retardant belt that is less dependent on the environment.

In order to solve the above-described problems, the present invention provides a conductive member for an image forming apparatus including a conductive roller having a conductive layer formed from a conductive polymer composition containing an ionic conductive additive salt and a conductive belt. There,
The conductive layer is made discontinuous phase comprising a continuous phase and the first non-continuous phase and a second discontinuous phase, the continuous phase and the discontinuous phase and the sea - exhibits the island structure, said first non-contiguous The polymer constituting the phase has a higher affinity for the cation and anion dissociable salt than the polymer constituting the continuous phase, and the first discontinuous phase can be dissociated into a cation and an anion. While Ru is unevenly distributed salts, above the second discontinuous phase and the continuous phase hardly distribute the salt, and, first discontinuous phase affinity between the salt of the respective phases of the polymer> continuous Phase> second discontinuous phase, and the electrical resistance value (volume resistivity) of each phase is first discontinuous phase <continuous phase <second discontinuous phase,
Conductivity for an image forming apparatus, characterized in that it is formed from the polymer composition having a volume resistivity of 10 ⁴ to 10 ¹² [Ω · cm] described in JIS K6911 measured under an applied voltage of 100 V. A sex member is provided.

  As a result of intensive studies by the present inventors, the present inventors paid attention to the arrangement of salts capable of realizing low electrical resistance and the affinity between the salt and the polymer, and the polymer material constituting the conductive member and the ion conductive additive to be blended This is based on the discovery of a phase structure that can prevent the salt from moving out of the composition while investigating and experimenting with the salt and maintaining good electrical properties due to ions.

Specifically, it has a phase structure consisting of a continuous phase and two or more discontinuous phases, a salt that can dissociate into a cation and an anion is unevenly distributed in the discontinuous phase, and has high conductivity and electrical resistance. A polymer constituting the first discontinuous phase in which a salt capable of dissociating into a cation and an anion having a high degrading ability is unevenly distributed is a salt capable of dissociating into such a cation and an anion than a polymer constituting the continuous phase. Has a high affinity. As a result, it is possible to suppress the outflow of the salt to the outside when an electric field is applied while increasing the degree of freedom of the salt in the discontinuous phase and maintaining a low electric resistance. It is possible to prevent an increase in resistance during continuous energization. Furthermore, since salt is present in the discontinuous phase, it is not easily affected by the environment such as temperature and humidity, and due to ionic conduction, variation in electrical resistance and voltage dependence are small.

Conventionally, in order to reduce the resistance value of the entire composition as much as possible, attempts have been made to distribute the salt to the continuous phase. However, the present invention relates to the affinity between the salt and the polymer and the arrangement of the salt. Paying attention to the above configuration, reducing the environmental dependency (temperature dependency + humidity dependency) of electrical resistance while maintaining a sufficiently low resistance value, and reducing the increase in resistance during continuous energization Made possible.
In particular, in the present invention, a salt having a high degree of ion dissociation and a high conductivity is used, and even if an electric field is continuously applied, the salt is hardly transferred out of the system. Without significantly increasing the value, excellent conductivity can be obtained with a small amount of a salt having excellent conductivity. Therefore, the influence on other physical properties such as compression set and hardness can be reduced as much as possible, and it is very useful as a conductive member such as a conductive roller or a conductive belt for an image forming apparatus such as a copying machine or a printer. It is.

  The phase structure of the polymer composition such as the continuous phase and the discontinuous phase can be observed, for example, with a phase mode of an atomic force microscope (AFM) type scanning probe microscope (SPM).

Two phases, the first discontinuous phase and the second discontinuous phase, are provided as the discontinuous phase, and the second discontinuous phase hardly contains the salt. Further, yet such have been added almost the salt in the continuous phase.
In this case, in addition to these conditions, the affinity with the polymer salt of each phase is as follows: first discontinuous phase> continuous phase> second discontinuous phase, and the electrical resistance value (volume resistivity) of each phase is 1 discontinuous phase <continuous phase <you are the second discontinuous phase.
The affinity of each phase with the polymer salt is the volume resistivity (ρ _V1 , ρ _V2 , ρ _V3 described later) of the polymer of each phase in the state containing no salt, and each phase in the state containing the salt. It can be evaluated from the volume resistivity of the polymer. It can be said that the lower the resistivity, the higher the affinity between the polymer and the salt.
By setting it as the said structure, the ratio of the 1st discontinuous phase in which the dissociable salt is unevenly distributed can be suppressed, without impairing electroconductivity very much. As a result, a low volume resistivity can be maintained as a whole composition even if the amount of dissociable salt is reduced.
The first discontinuous phase is preferably present so as to surround the second discontinuous phase. Further, the first discontinuous phase, the second discontinuous phase, and the continuous phase may each be formed of two or more kinds of polymers, or each of them may be divided into several finer phases. As long as the purpose and utility are satisfied.

Assuming that the volume resistivity of the polymer constituting the first discontinuous phase in which salts dissociated into cations and anions are unevenly distributed is ρ _V1 , and the volume resistivity of the polymer constituting the continuous phase is ρ _V2 , 0.2 ≦ log ₁₀ ρ _V2 −log ₁₀ ρ _V1 ≦ 5 is preferable.
This is because, when the above value is smaller than 0.2, a salt that can be dissociated into the continuous phase is easily transferred. On the other hand, if the above value is larger than 5, it is difficult to achieve low resistance as a whole, and it becomes difficult to obtain a uniform composition. In addition, when the polymer which comprises one phase is made into the blend of two or more types of polymers, it is set as the volume resistivity of the blended polymer. Moreover, the volume resistivity here is a volume resistivity of only the polymer containing no salt. Incidentally, the _{log 10 ρ V2} -log _{10 ρ V1} more preferably as long as 0.5 to 4, further preferably in the range from 1 to 3.

The weight ratio of the polymer constituting the discontinuous phase and the polymer constituting the continuous phase is (polymer constituting the discontinuous phase: polymer constituting the continuous phase) = (5:95) to (75:25). It is preferable.
If the blending ratio of the polymer constituting the discontinuous phase is less than the above range, the volume fraction of the discontinuous phase is too low, so the volume resistivity of the entire composition, or the resistance of the roller or belt molded from the composition The value cannot be lowered sufficiently. On the other hand, if the blending ratio of the polymer constituting the continuous phase is less than the above range, even if a technique such as dynamic crosslinking is used, it cannot be present as the continuous phase.
The weight ratio is more preferably (10:90) to (60:40), and more preferably (20:80) to (45:55).
In the present invention, the electric resistance value can be controlled to some extent by changing the ratio of the continuous phase and the discontinuous phase while keeping the blending amount of the dissociable salt fixed. If dynamic crosslinking is used, a relatively high fraction component can be brought into the discontinuous phase, and the ratio of the polymer constituting the discontinuous phase can be increased.
The volume fractions of the continuous phase, the first discontinuous phase, and the second discontinuous phase are preferably continuous phase> second discontinuous phase> first discontinuous phase.

The salt capable of dissociating into a cation and an anion is preferably blended at a ratio of 0.01 parts by weight or more and 20 parts by weight or less with respect to 100 parts by weight of all polymer components.
This is because if the amount is smaller than 0.01 parts by weight, a sufficient electric resistance reduction effect cannot be obtained. If the amount is larger than 20 parts by weight, the cost is increased. This is because it becomes difficult to obtain. In addition, More preferably, it is 0.2 to 10 weight part, More preferably, it is 0.4 to 6 weight part.

The salt capable of dissociating into a cation and an anion was measured in a mixed solvent of propylene carbonate (PC) / dimethyl carbonate (DME) (volume fraction 1/2) at a salt concentration of 0.1 mol / liter at 25 ° C. The conductivity is preferably 2.3 mS / cm or more. This conductivity is proportional to the concentration of dissociated ions and their mobility. If it is smaller than the above range, it is difficult to obtain a low resistance value. It is more preferable if it is 3.5 mS / cm or more. In addition, although the electrical conductivity of this salt is so preferable that it is large, the upper limit of the electrical conductivity of the salt which exists actually is about 4.5 mS / cm.
Examples of the salt in such a range include CF ₃ SO ₃ Li {: 2.3 mS / cm}, C ₄ F ₉ SO ₃ Li {: 2.3 mS / cm}, (CF ₃ SO ₂ ) ₂ NLi {: 4 0.0 mS / cm}, (C ₂ F ₅ SO ₂ ) ₂ NLi {: 3.8 mS / cm}, (C ₄ F ₉ SO ₂ ) (CF ₃ SO ₂ ) NLi {: 3.5 mS / cm}, ( FSO ₂ C ₆ F ₄ ) (CF ₃ SO ₂ ) NLi {: 3.0 mS / cm}, (C ₈ F ₁₇ SO ₂ ) (CF ₃ SO ₂ ) NLi {: 3.2 mS / cm}, (CF ₃ CH ₂ OSO ₂ ) ₂ NLi {: 3.0 mS / cm}, (CF ₃ CF ₂ CH ₂ OSO ₂ ) ₂ NLi {: 3.0 mS / cm}, (HCF ₂ CF ₂ CH ₂ OSO ₂ ) ₂ NLi { _{: 2.9mS / cm}, ((} CF 3) 2 CHOS _{2) 2 NLi {: 3.1mS /} cm}, (CF 3 SO 2) 3 CLi {: 3.6mS / cm}, (CF 3 CH 2 OSO 2) 3 CLi {: 2.9mS / cm}, LiPF ₆ {: 4.4 mS / cm} and the like. In addition, the value in {:} is the value of the conductivity.
The use of a salt having a high conductivity as described above is preferable because a very low electrical resistance value can be obtained literally by addition of a small amount. On the other hand, when such a salt is used, the effect of the present invention is particularly good. It can be said that it is possible to remarkably exhibit. This is because such a salt having a high conductivity is likely to move in the system, and if the present invention is not used, the increase in resistance during continuous use is likely to be significantly greater than that of a salt having a low conductivity.

Further, as dissociable salts with the cations and anions, fluoro group (F-) and a sulfonyl group (-SO 2 _-) salts with anions with, for example, bis (fluoroalkyl sulfonyl) imide ion, tris Lithium salts, potassium salts, quaternary ammonium salts and imidazolium salts with anions such as (fluoroalkylsulfonyl) methide ions and fluoroalkylsulfonic acid ions are preferably used. In such a salt, since a functional group such as a fluoro group or a sulfonyl group has an electron withdrawing property, the anion is further stabilized and the ion exhibits a higher degree of dissociation. Thereby, a very low electric resistance value can be obtained with a small amount of addition.
The quaternary ammonium salt and imidazolium salt can change the dielectric constant, capacitance, etc. by changing the functional group such as an alkyl group to be substituted. For example, the capacitance can be reduced.

In addition, as described above, bis (fluoroalkylsulfonyl) imide ion, tris (fluoroalkylsulfonyl) methide ion, fluoroalkylsulfonic acid ion, particularly bis (trifluoromethanesulfonyl) imide ion, as anions having a fluoro group and a sulfonyl group , Tris (trifluoromethanesulfonyl) methide ion, and trifluoromethanesulfonate ion, preferably selected from at least one selected from the group consisting of ions.
Thereby, environmental dependency such as volume resistivity can be improved, the degree of dissociation is very large, and the polymer constituting the first discontinuous phase such as EO-PO-AGE copolymer and epichlorohydrin rubber This is also preferable from the viewpoint of high compatibility. In addition, among the above-mentioned salts, when a salt made of bis (fluoroalkylsulfonyl) imide ion or tris (fluoroalkylsulfonyl) methide ion is used, environmental dependency such as volume resistivity can be extremely reduced.

The cation of the salt having an anion having a fluoro group and a sulfonyl group is preferably an alkali metal, group 2A, transition metal, or amphoteric metal cation. Alkali metals are particularly preferable because they have a low ionization energy and can easily form stable cations. In addition to the metal cation, a salt having a cation represented by the following chemical formula (Chemical Formula 2, Chemical Formula 3) can also be used. In the formula, R _{1 to} R ₆ are each an alkyl group having 1 to 20 carbon atoms or a derivative thereof, and R _{1 to} R ₄ , and R ₅ and R ₆ may be the same or different. Among these, three of R _{1 to} R ₄ are methyl groups, and the other one is an alkyl group having 4 to 20 carbon atoms, more preferably 6 to 20 carbon atoms, or a derivative thereof. A salt composed of an ammonium cation is particularly preferred because the positive charge on the nitrogen atom can be stabilized by three methyl groups having strong electron donating properties, and the compatibility with the polymer can be improved by other alkyl groups or derivatives thereof. In addition, in the cation of the chemical formula 3, R ₅ or R ₆ is preferably a methyl group or an ethyl group because it is easier to stabilize the positive charge on the nitrogen atom if it has an electron donating property. In this way, by stabilizing the positive charge on the nitrogen atom, the stability as a cation can be increased, and the salt can have a higher dissociation degree and thus excellent conductivity imparting performance.

  For the reasons described above, salts having an anion having a fluoro group and a sulfonyl group include alkali metal salts of bis (trifluoromethanesulfonyl) imide, alkali metal salts of tris (trifluoromethanesulfonyl) methide, alkali of trifluoromethanesulfonic acid. Most preferably, the salt is selected from at least one of the group consisting of metal salts.

  Salts having anions consisting of bis (fluoroalkylsulfonyl) imide ions and tris (fluoroalkylsulfonyl) methide ions, especially bis (trifluoromethanesulfonyl) imide lithium, have been used in the past because they are stable even at very high temperatures. Unlike lithium perchlorate and perchloric acid quaternary ammonium salts, etc., there is no need for measures such as making them explosion-proof. From this point, the manufacturing cost can be reduced and the safety can be ensured, which is very good.

The salt capable of dissociating into a cation and an anion is preferably blended without a medium comprising a low molecular weight polyether compound having a molecular weight of 10,000 or less or a low molecular weight polar compound. If such a medium is used for a long period of time, the electrical resistance value is greatly increased, the current-carrying characteristics are deteriorated, and the medium is precipitated together with ions, so that the photosensitive member is liable to be contaminated. Specific examples of the low molecular weight polyether compound having a molecular weight of 10,000 or less include polyethylene glycol, polypropylene glycol, polyether polyol and the like having a low molecular weight (generally having a molecular weight of several hundred to several thousand). Further, examples of the low molecular weight polar compound include low molecular weight polyester polyols having a molecular weight of 10,000 or less, adipic acid esters, phthalic acid esters, and the like.
A known method can be used as a method of blending a dissociable salt without using the above medium. For example, after dry blending with a Henschel mixer, tumbler, etc., a blend containing a dissociable salt and polymer is melt-mixed with a single or twin screw extruder, Banbury mixer, kneader, etc. I can do it. In addition, when a dissociable salt is blended at a high temperature in a thermoplastic resin or thermoplastic elastomer polymer system, it may be used under an inert gas atmosphere such as nitrogen for the purpose of preventing deterioration of the polymer. Mixing (mixing) can also be performed.

  The conductive polymer composition of the present invention is preferably a vulcanized rubber composition or a thermoplastic elastomer composition because it can impart appropriate elasticity and the like, but a resin may be used as the polymer.

  Since the polymer constituting the first discontinuous phase in which the salt capable of dissociating into a cation and an anion is unevenly distributed can be strongly stabilized by an ether bond or a cyan group, the salt and the polymer It is preferable that the main component is at least one of a polyoxyalkylene copolymer, a cyan group-containing polymer, and an epichlorohydrin polymer. Thus, by increasing the affinity between the polymer constituting the first discontinuous phase and the salt, the resistance value of the entire composition can be effectively reduced, and precipitation of the salt outside the system, It is possible to prevent the resistance value from increasing during continuous use.

  Specifically, it is preferable to use ethylene oxide-propylene oxide-allyl glycidyl ether copolymer (EO-PO-AGE copolymer) or / and epichlorohydrin rubber as the polymer constituting the first discontinuous phase. . As epichlorohydrin rubber, epichlorohydrin-ethylene oxide copolymer, epichlorohydrin-ethylene oxide-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-propylene oxide-allyl glycidyl ether copolymer, epichlorohydrin-ethylene oxide-propylene oxide copolymer And epichlorohydrin-allyl glycidyl ether copolymer.

In addition, a polyethylene oxide block polyamide copolymer and a polyether ester amide copolymer also have a high affinity with the salt used in the present invention, and are preferably used as a polymer constituting the first discontinuous phase.
Specifically, for example, the first discontinuous phase is a polyether polymer, the continuous phase is low nitrile NBR, the second discontinuous layer is EPDM, the low nitrile NBR is 90 to 50% by weight, the polyether polymer is It is good to mix | blend 0.5-25 weight%, EPDM 10-40 weight%, and the said salt 0.1-2 weight%.

When the EO-PO-AGE copolymer is used, the copolymerization ratio can be set so that the volume resistivity can be reduced while maintaining the physical properties (compression set, hardness) of the composition. In the copolymer, the ethylene oxide ratio is preferably 55 mol% or more and 95 mol% or less, and more preferably 65 mol% or more and 92 mol% or less. Ionic conductivity is exhibited because oxonium ions and metal cations in the polymer (for example, cations such as lithium ions in the added salt) are stabilized by ethylene oxide units and propylene oxide units. , By being transported by the segmental motion of the molecular chain of that part. In general, ethylene oxide units have a higher stabilizing ability than propylene oxide units. Therefore, a higher ratio of the ethylene oxide unit can stabilize more ions and realize a lower resistance. On the other hand, when the ratio of the ethylene oxide unit exceeds 95 mol%, the ethylene oxide unit is crystallized and it becomes difficult to transport ions, and the electrical resistance increases.
When an EO-PO-AGE copolymer is used, the copolymerization ratio of allyl glycidyl ether is preferably 1 mol% or more and 10 mol% or less. If it is less than 1 mol%, bleed or photoconductor contamination is likely to occur, while if it exceeds 10 mol%, the number of crosslinking points after vulcanization will increase, making it difficult to achieve low resistance, as well as tensile strength and fatigue. Characteristics and flex resistance are likely to deteriorate. Further, the number average molecular weight of the EO-PO-AGE copolymer is preferably 10,000 or more, more preferably 50,000 or more. The reason is to prevent bleed bloom and photoconductor contamination.

  The polymer constituting the continuous phase is preferably a low nitrile NBR or / and a medium / high nitrile NBR or a polyester-based thermoplastic elastomer. As a result, the resistance value as a whole can be made as low as possible, and the dissociable salt can be prevented from shifting out of the composition and from increasing in resistance during continuous energization. As the material of the continuous phase, since the electrical resistance value is low to some extent and the Tg is low, the temperature dependence of the viscoelasticity near room temperature is small, thereby making it possible to reduce the environmental dependence of the volume resistivity. Particularly preferred are low nitrile NBR and the like. The Tg of these polymers is -40 ° C or lower, more preferably -50 ° C or lower. The lower the Tg, the better. However, considering searching for a polymer that is actually present or in practical use in consideration of cost, it is −120 ° C. or higher, −100 ° C. or higher, or − It becomes about 80 ° C. or higher.

The second discontinuous phase that does not disperse a salt that can dissociate into a cation and an anion is preferably mainly composed of a low-polar rubber. Specifically, the low polarity rubber is at least one rubber selected from ethylene propylene diene copolymer rubber (EPDM), ethylene propylene rubber (EPM), butyl rubber (IIR), and styrene butadiene rubber (SBR). Is preferred. Thereby, ozone resistance can be provided to a composition. For example, even when used for a conductive member or the like used in an image forming apparatus, ozone resistance can be secured against ozone generated in the apparatus.
Furthermore, in order to reduce the temperature dependence of the viscoelasticity of the entire system near room temperature and to reduce the environmental dependence of the electrical resistance value, not only the polymer used for the continuous phase but also the polymer used for the second discontinuous phase. Those having a lower Tg are preferred. The same applies to the polymer used for the first discontinuous phase. The Tg of these polymers is preferably −40 ° C. or lower, and more preferably −50 ° C. or lower. As for the lower limit of the Tg of the polymer used for the first discontinuous phase or the second discontinuous phase, the lower the better, as in the case of the polymer constituting the continuous phase, but in practice, −120 ° C. or higher, or -100 ° C or higher, or -80 ° C or higher.

  In addition, a part of the ions generated from the added salt can be converted into a single ion by using an anion adsorbent or the like to stabilize the conductivity or improve the conductivity when added in a small amount. Anion adsorbents include synthetic hydrotalcite mainly composed of Mg and Al, inorganic ion exchangers such as Mg-Al, Sb, and Ca and co-heavy having an ion site for fixing anions in the chain. Known compounds such as coalescence are useful. Specifically, synthetic hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd., trade name Kyoward 2000, Kyoward 1000), anion exchange ion exchange resin (manufactured by Nippon Nensui Co., Ltd., trade name Dyanon DCA11), etc. Is mentioned.

  When a polymer containing halogen such as chlorine is used as the polymer, it is preferable to incorporate an acid acceptor such as hydrotalcite in order to prevent deterioration of the polymer due to dehydrochlorination reaction and rusting of the kneader. In the case of synthetic hydrotalcite, the blending amount is 1 to 15 parts by weight, preferably 3 to 12 parts by weight, based on 100 parts by weight of the halogen-containing polymer.

As the vulcanizing agent to be added, sulfur is particularly preferable because low electrical resistance can be realized. In addition to sulfur and organic sulfur-containing compounds, peroxides can be used, and these can be used in combination. In particular, when EPDM, EPM, or the like is used as the low-polar rubber forming the second discontinuous phase, the peroxide phase can be effectively vulcanized.
Examples of the organic sulfur-containing compound include tetraethylthiuram disulfide and N, N-dithiobismorpholine. Examples of the peroxide include dicumyl peroxide and benzoyl peroxide. Of these, when foaming is performed together with vulcanization, it is preferable to use sulfur from the viewpoint of improving the balance between the vulcanization speed and the foaming speed. The addition amount of the vulcanizing agent is 0.5 to 5 parts by weight, preferably 1 to 3 parts by weight, based on 100 parts by weight of the polymer component.

Moreover, you may mix | blend a vulcanization accelerator and can use inorganic promoters, such as slaked lime, magnesia (MgO), and risurge (PbO), and the organic promoter described below.
Organic promoters include 2-mercapto-benzothiazole, thiazoles such as dibenzothiazyl disulfide, sulfenamides such as N-cyclohexyl-2-benzothiazylsulfenamide, tetramethylthiuram monosulfide, tetramethylthiuram Thiurams such as disulfide, tetraethylthiuram disulfide, and dipentamethylenethiuram tetrasulfide, and thioureas can be used in appropriate combination.
The vulcanization accelerator is preferably 1 part by weight or more and 5 parts by weight or less, and more preferably 2 parts by weight or more and 4 parts by weight or less with respect to 100 parts by weight of the polymer component.

Further, a vulcanization acceleration aid may be blended, and examples thereof include metal oxides such as zinc white, fatty acids such as stearic acid, oleic acid, and cottonseed fatty acid, and other conventionally known vulcanization acceleration aids.
You may mix | blend a chemical foaming agent in the ratio of 3 to 12 weight part with respect to 100 weight part of polymer components for provision of a softness | flexibility etc. In addition, you may mix | blend softeners, such as oil, anti-aging agent, etc.
Further, for the purpose of improving the mechanical strength, a filler can be blended as necessary within a range not impairing the electrical characteristics and other physical properties. Examples of the filler include powders such as silica, carbon black, clay, talc, calcium carbonate, magnesium carbonate, and aluminum hydroxide. The filler is preferably 5 to 60 parts by weight with respect to 100 parts by weight of the polymer.

The conductive polymer composition of the present invention is more preferably non-chlorine or non-bromine without using a salt containing chlorine or bromine.
Specifically, a polymer that does not contain chlorine / bromine is used as a polymer, and a salt containing chlorine / bromine such as lithium perchlorate, sodium perchlorate or quaternary ammonium perchlorate is not used. By using a non-chlorine or non-bromine composition as a whole, there is no risk of corroding, rusting or contaminating the metal surface such as the shaft of the conductive roller. Furthermore, an incineration process after use can be performed very easily, and an environmentally friendly composition can be obtained.

  The conductive polymer composition forming the conductive layer of the conductive member of the present invention is a vulcanized rubber and thermoplastic rubber permanent strain test method described in JIS K6262, with a measurement temperature of 70 ° C., a measurement time of 22 to 24 hours, The compression set measured at a compression rate of 25% is preferably 30% or less. This is because if the ratio is larger than 30%, the dimensional change becomes too large when the composition is molded and used as a conductive member such as a roller or a belt, which may not be suitable for practical use. More preferably, it is 25% or less, and the smaller the better. However, in consideration of the current blending technique and measurement accuracy, a value of about 1% or more is actually possible.

The conductive polymer composition forming the conductive layer of the conductive member of the present invention has a volume resistivity of 10 ^4.0 to 10 ^12.0 [Ω measured according to JIS K6911 measured under an applied voltage of 100V. · Cm], preferably 10 ^6.0 to 10 ¹⁰ [Ω · cm], more preferably 10 ^7.5 to 10 ^9.5 [Ω · cm]. This is because when the volume resistivity is larger than 10 ^12.0 [Ω · cm], when the conductive member is used, good conductivity cannot be obtained and it is not suitable for practical use. In addition, when the composition is molded into a roller, a belt, or the like, the efficiency of transfer, charging, toner supply, etc. is likely to decrease. On the other hand, if the volume resistivity is smaller than 10 ^4.0 [Ω · cm], it may be difficult to retain electric charges, and the function as a member of the image forming apparatus may be lost.

The conductive member provided with the conductive layer is a conductive roller or conductive belt used in an image forming apparatus in a roller shape or an endless belt shape.
The conductive member comprising the conductive roller or the conductive belt includes a salt constituting a first discontinuous phase in which a salt dissociable into a cation and an anion and a salt dissociable into the cation and an anion are unevenly distributed. A conductive polymer composition obtained by kneading or uniformly mixing and kneading again or adding a polymer constituting a continuous phase or a polymer constituting a second discontinuous phase to the kneaded product or the mixture. Made,
A conductive member made of a conductive roller or a conductive belt provided with a conductive layer is manufactured by thermoforming the conductive polymer composition.
Thus, a conductive polymer in which a salt dissociable into a cation and an anion is unevenly distributed in a desired polymer, and a polymer in which a salt dissociable into a cation and an anion is unevenly distributed is a first discontinuous phase. By forming the composition into a desired shape such as a roller shape or a belt shape by extrusion or the like, a conductive member provided with a conductive layer exhibiting good conductivity can be easily produced.

When a conductive roller is used, a resistance value R [Ω] is measured when a constant voltage of 1000 V is continuously applied for 96 hours in an environment of 23 ° C. and a relative humidity of 55%, and an increase in resistance value Δlog ₁₀ The value of R = log ₁₀ R (t = 96 hr.) − Log ₁₀ R (t = 0 hr.) Is preferably 0.5 or less. This is because if the index value of the amount of increase in the roller resistance value specified above is larger than 0.5, the increase in resistance when the conductive roller is continuously used becomes large, and a larger power source is required. This is because there is a possibility of impeding practical use. The smaller the index value of the amount of increase, the better. However, considering the measurement accuracy and the level of the current blending technique, it is about 0.01 or more, 0.05 or more, or 0.08 or more.
On the other hand, when a conductive belt is used, the volume resistivity when a constant voltage of 1000 V is applied continuously for 5 hours to a sample having a thickness of 0.25 mm in an environment of 23 ° C. and 55% relative humidity. ρv [Ω · cm] is measured, and the volume resistivity increase amount Δlog ₁₀ ρv = log ₁₀ ρv (t = 5 hr.) − log ₁₀ ρv (t = 0 hr.) is 0.5 or less. preferable. When it exceeds 0.5, the same problem as that of the conductive roller occurs. As for the lower limit of the increase amount, the smaller the better, as in the case of the conductive roller, but considering the measurement accuracy and the level of the current blending technology, 0.01 or more, or 0.1 or more, Or it becomes about 0.3 or more.

In addition, the roller resistance value R [Ω] or the volume resistivity ρv [Ω · cm] of the conductive belt under the conditions of 10 ° C. relative humidity 15%, 32.5 ° C. relative humidity 90%, and the roller resistance value are measured. Or the environmental dependency of the volume resistivity of the belt Δlog ₁₀ R = log ₁₀ R (10 ° C. relative humidity 15%) − log ₁₀ R (32.5 ° C. relative humidity 90%), or Δlog ₁₀ ρv = log ₁₀ It is preferable that the value of ρv (10 ° C. relative humidity 15%) − log ₁₀ ρv (32.5 ° C. relative humidity 90%) is 1.7 or less.
This is because if the index value of the environmental dependency of the roller resistance value or the belt volume resistivity is greater than 1.7, the resistance value changes greatly due to the change in the use environment of the conductive member, so a larger power source is required. This is because power consumption and product cost of the image forming apparatus increase.
In particular, in the case of a conductive roller, the index value for the environmental dependency of the resistance value is 1.4 or less, more preferably 1.3 or less, and even more preferably 1.2 or less. The smaller the index value, the better. However, considering the measurement accuracy and the current technical level, the index value is 0.1 or more, 0.5 or more, or 0.8 or more.
In the case of a conductive belt, the index value of the environmental dependency of the resistance value is preferably 1.6 or less, and the smaller the better, but in view of measurement accuracy and current technical level, 0.1 or more, or 0.5 or more, or about 1.0 or more. The conductive member for an image forming apparatus of the present invention has a level of environment that could not be realized by a member made of a conventional ion conductive rubber composition or a reaction curing type ion conductive urethane composition that is not thermoplastic. Reduces dependency.

  When the conductive member, particularly a conductive roller, is used, the expansion ratio (volume%) is 100% or more and 500% or less, and the hardness measured with a type E durometer described in JIS K6253 is 60 degrees or less. A foamed layer is preferred. Thereby, flexibility is improved, and when used for a transfer roll or the like, the toner image is hardly disturbed when the transfer member is pressed, and a good image can be obtained. Even in the case where the surface area of the conductive layer in the conductive member is increased as described above, the present invention can be used to prevent migration contamination and suppress an increase in resistance during energization. . As can be seen from the examples and comparative examples described later, the resistance increase during continuous energization in the case of the foam layer is generally considerably larger than that in the case of solid, but even in such a case, according to the present invention. The supplied conductive (foamed) member can suppress such an increase in resistance and is excellent. The expansion ratio is more preferably 150% or more and 300% or less, and further preferably 200% or more and 270% or less. Further, the hardness (durometer E hardness) is more preferably 20 degrees or more and 40 degrees or less, and further preferably 25 degrees or more and 35 degrees or less.

The conductive roller may have a configuration including a cylindrical conductive layer and a cylindrical cored bar, and may include only one conductive layer around the cored bar. For protection and the like, a multi-layer structure such as two layers or three layers may be used, and the type of each layer, the stacking order, the stacking thickness, and the like can be appropriately set according to the required performance. The core metal can be made of metal such as aluminum, aluminum alloy, SUS, iron, or ceramic. In addition, the surface of the conductive roller can be irradiated with ultraviolet rays and various coatings to prevent paper dust and toner from sticking.
The conductive roller is used in an image forming apparatus. Specifically, a charging roller for uniformly charging the photosensitive drum, a developing roller for attaching toner to the photosensitive member, and a toner image from the photosensitive member. It is used as a transfer roller for transferring to paper or an intermediate transfer belt, a toner supply roller for transporting toner, and a drive roller for driving the transfer belt from the inside.

The conductive roller can be produced by a conventional method. For example, the conductive polymer composition (kneaded material) is preformed into a tube shape with a single screw extruder, and the preform is vulcanized at 160 ° C. for 15 to 70 minutes. After that, after inserting and adhering the cored bar and polishing the surface, various conventionally known methods such as cutting to a required dimension to form a roller can be used. The vulcanization time may be determined by determining the optimum vulcanization time using a vulcanization test rheometer (eg, curast meter). Further, the vulcanization temperature may be determined by raising or lowering the temperature as necessary. In order to reduce photoreceptor contamination and compression set, it is preferable to set conditions so as to obtain a sufficient vulcanization amount. In addition, about the vulcanization method of a roller, you may vulcanize | cure in the vulcanization can under a steam pressurization, and about the possible mixing | blending, you may take the method by continuous vulcanization. Moreover, you may perform secondary vulcanization as needed. Further, the conductive roller preferably has a roller resistance value of 10 ^3.5 Ω to 10 ^11.0 Ω at an applied voltage of 1000 V, more preferably 10 ^4.0 Ω to 10 ^9.0 Ω, Furthermore, 10 ^4.5 Ω to 10 ^8.5 Ω is preferable.

The conductive belt may have only one conductive layer, and in addition to the conductive layer, a layer is provided on the inner peripheral surface or the outer peripheral surface for resistance adjustment, surface protection, and the like. It is good also as a structure. Depending on the required performance, the type, stacking order, stacking thickness, etc. of each layer can be set as appropriate. In addition, the surface of the conductive belt can be irradiated with ultraviolet rays and various coatings to prevent paper dust and toner from sticking.
The conductive belt is used in an image forming apparatus. Specifically, the conductive belt is used as a transfer belt, an intermediate transfer belt, a fixing belt, a photoreceptor substrate belt, or the like.
In the case of a transfer belt or intermediate transfer belt, urethane, acrylic, rubber, etc., depending on the purpose, to make it easier to scrape off the toner remaining at the time of transfer, to change toner detachability, to control surface energy, etc. It is preferable to provide a coating layer in which a known material, such as latex or the like, in which a fluorine-based resin is dispersed is applied by a known method such as electrostatic coating, spray coating, dipping, or brush coating. The thickness of the coating layer is preferably 1 μm to 20 μm. Thereby, the further functional enhancement of the belt can be realized.

The conductive belt is a belt in which the conductive polymer composition (kneaded material) is 200 to 270 ° C., preferably 200 to 250 ° C., more preferably 220 to 240 ° C. by an extruder for resin. Various conventionally known methods such as forming the belt main body by air cooling after being extruded into a shape can be used.
The thickness of the extruded belt is preferably 50 μm to 500 μm. It can be made variable by adjusting the gap of the die lip at the time of extrusion molding and adjusting the discharge amount of the thermoplastic composition and the take-up speed of the belt.
The above range is that when the thickness is less than 50 μm, the film tends to be stretched, and for example, misalignment is likely to occur when a multicolor toner is formed on a color image forming apparatus using a color image forming apparatus. On the other hand, if it is thicker than 500 μm, the bending rigidity of the belt becomes high and it becomes difficult to suspend the belt on the drive shaft. Further, the surface roughness Rz of the outer surface of the belt is preferably 2.0 μm or less, and more preferably 1.8 μm or less. Thereby, transfer efficiency, transportability, and toner cleaning properties can be improved.

The conductive belt is particularly preferably a flame retardant belt.
As a second invention of the flame retardant belt ,
A conductive member for an image forming apparatus comprising a conductive layer formed from a conductive polymer composition containing an ion conductive additive salt,
The conductive layer includes a continuous phase and one or more discontinuous phases. The continuous phase and the discontinuous phase have a sea-island structure, and at least one of the discontinuous phases is a cation. And a first discontinuous phase in which a salt dissociable into anions is unevenly distributed, and the polymer constituting the first discontinuous phase is a salt capable of dissociating into the cation and anion than the polymer constituting the continuous phase. With high affinity,
The conductive polymer composition contains 95 to 50 parts by weight of a polyester-based thermoplastic elastomer with respect to 100 parts by weight of all polymer components, and melamine shear, which is a flame retardant with respect to 100% by weight of the polymer composition. In addition to containing 15% by weight to 40% by weight of nurate, and 0.01 parts by weight to 3 parts by weight of the salt having the anion described in Chemical Formula 1 below with respect to 100 parts by weight of the total polymer component. According to JIS K6911, a copolymer containing a polyether block and contained in a proportion of 5 to 50 parts by weight with respect to 100 parts by weight of the polyester-based thermoplastic elastomer was measured under an applied voltage of 100V. characterized in that the volume resistivity of the flame-retardant seamless belt is less 1.0 × 10 ⁶ Ω · cm or more 1.0 × ^{10 12} Ω · cm It provides a conductive member for an image forming apparatus.
(Wherein X ₁ and X ₂ are functional groups having 1 to 8 carbon atoms, including C, F—, —SO ₂ —).

  Since the belt having the above-described configuration contains a copolymer having a polyether block, the polyether structure stabilizes salt ions in the composition. That is, the copolymer having a polyether block selectively takes in the salt having an anion represented by the above chemical formula 1 that exhibits ionic conductivity, and is dispersed in a polyester-based thermoplastic elastomer in a sea-island structure. Even if melamine cyanurate is added as a flame retardant, the volume resistivity of the belt and its environmental dependency are not affected, and the electric resistance of the belt does not change. Flame retardancy can be imparted.

Therefore, since the outflow of the salt to the outside of the polymer when an electric field is applied can be suppressed while maintaining the flame retardancy, the migration of the salt to the outside of the polymer and the increase in resistance during continuous energization can be prevented. It is possible to suppress an increase in volume resistivity due to continuous energization while effectively reducing the resistance.
As described above, since the flame retardant belt has excellent flame retardancy, it can be used in an image forming apparatus even under high voltage and high temperature conditions without being limited by the use state, thereby improving image quality. Can be achieved. In addition, the resistance of the belt can be easily adjusted, the variation in the resistance value in the belt surface is small, and the resistance dependency of the resistance value on the environment and the increase in resistance during continuous energization can be reduced.
For example, when used as an intermediate transfer belt, good transfer performance can be obtained over a long period of time without causing transfer displacement or transfer failure. Further, it can also be used for a conveyor belt, a developing belt, a fixing belt, a belt-type photoreceptor base belt, and the like, and each can provide better performance than conventional ones.

The salt having an anion described in Chemical Formula 1 is stabilized as an anion due to the electron withdrawing property of the fluoro group and the sulfonyl group in the functional groups of X ₁ and X ₂ in Chemical Formula 1, and the ion is more dissociated. Degrees. Thereby, a very low electric resistance value can be obtained with a small amount of addition. In addition, this salt has high chemical and electrochemical stability with respect to electrodes and the like, and has high safety. In addition, the usable temperature range is wide, the electrical resistance can be easily adjusted, and there is little variation in the resistance value in the belt surface. A belt that is less likely to cause body contamination can be obtained. Furthermore, it is easy to obtain, is a powder at room temperature, is easy to knead, and can smooth the surface skin even if it is extruded. In particular, it is possible to make the extruded skin smooth when extruding a polyether polyester polymer or the like.

In the anion described in the chemical formula 1, in the formula, each of X ₁ and X ₂ may be any functional group having 1 to 8 carbon atoms including all of C, F—, —SO ₂ —, and stable. Further, from the viewpoints of property, cost, and handleability, X ₁ − in Chemical Formula 3 is C _n1 H _m1 F _{(2n1−m1 + 1)} —SO ₂ —, and X ₂ − is C _n2 H _m2 F _{(2n2 − m2 + 1)} —SO ₂ — (n1 and n2 are integers of 1 or more, and m1 and m2 are integers of 0 or more).

  The cation paired with the anion described in Chemical Formula 1 to form a salt is preferably an alkali metal, 2A group, transition metal, or amphoteric metal cation. Since ionization energy is small, it is preferable because stable cations are easily formed. In particular, the metal constituting the cation is preferably lithium having high conductivity. In addition to the metal cation, a salt having a cation represented by the above chemical formula 2 (Chemical formula 2) or Chemical formula 3 (Chemical formula 3) can also be used.

Among the salts with anions described in Chemical Formula 1, lithium-bis (trifluoromethanesulfonyl) imide ((CF ₃ SO ₂ ) ₂ NLi) has a melting point of 228 ° C. and kneading and belt processing temperature (200 ° C. to 270 [deg.] C., preferably 200 [deg.] C. to 240 [deg.] C.), which is particularly preferable because it is more easily taken into the polyether segment. In addition, the above-described salts can be used, and a plurality of types may be used in combination.

The copolymer having a polyether block is contained in a proportion of 5 to 50 parts by weight, further 10 to 50 parts by weight, based on 100 parts by weight of the polyester-based thermoplastic elastomer.
If the amount is less than 5 parts by weight, it is difficult to achieve a sufficiently low volume resistivity while suppressing an increase in volume resistivity during continuous energization. On the other hand, if the amount is more than 50 parts by weight, the properties such as moderate elasticity and excellent durability of the polyester thermoplastic elastomer, which is the main component of the belt, are impaired, and the moldability tends to deteriorate.

  The weight of the copolymer having a polyether block is preferably 1.6 to 3333 times, more preferably 10 to 3000 times the weight of the salt having the anion described in Chemical Formula 1. Thereby, good electrical characteristics can be obtained while maintaining good extruded skin. If the range is smaller than the above range, the stabilization of ions by the copolymer having a polyether block and the dispersion of the salt in the copolymer having a polyether block become insufficient, and during continuous energization This is because it is difficult to suppress an increase in resistance value. On the other hand, when it is larger than the above range, the salt concentration is lowered, and it is difficult to sufficiently reduce the electric resistance value of the belt.

Since the copolymer having the polyether block can ensure a certain degree of compatibility with the base polymer by a structure other than the polyether, good physical properties and processability can be obtained.
In particular, since it is used in combination with the salt having the anion described in Chemical Formula 1, the resistance value can be easily adjusted, and in-plane unevenness of the electric resistance value of the belt is eliminated, and the environmental dependency is also reduced. In addition, the resistance value can be efficiently reduced while maintaining good extruded skin.

The glass transition temperature Tg of the copolymer having a polyether block is preferably −40 ° C. or lower, more preferably −50 ° C. or lower, and the lower the better. This is because if Tg is higher than −40 ° C., the environmental dependency of volume resistivity tends to increase.
As described above, when the Tg is in a region where the temperature is low to some extent, the temperature dependence of the elastic modulus change in the belt use temperature region is small, and thereby the environmental dependence of the volume resistivity can be reduced. In general, the Tg of the copolymer having a polyether block in the present invention is about −80 ° C. or higher in consideration of conditions such as mass production and easy availability.
In addition, it is preferable that the glass transition temperature Tg of a polyester-type thermoplastic elastomer is also -40 degrees C or less.

  The copolymer having a polyether block is preferably at least one selected from the group consisting of a polyethylene oxide block polyamide copolymer and a polyether ester amide copolymer. These have a high affinity with the salt having an anion described in Chemical Formula 1 above, can be adjusted to a good electrical resistance value, and maintain good physical properties of the polyester-based thermoplastic elastomer as a base material. be able to. In addition, a resin-type antistatic agent such as a polyether block polyolefin resin may be used. The copolymer may contain a salt such as sodium perchlorate.

  In particular, a polyethylene oxide block polyamide copolymer is preferable, and a polyethylene oxide block nylon copolymer is particularly preferable. Specifically, a polyethylene oxide block nylon 11 copolymer, a polyethylene oxide block nylon 12 copolymer, a polyethylene oxide block nylon 6 copolymer, or the like can be used. A plurality of polymers may be used in combination.

Also, a blend of a polyamide homopolymer and a blend of a polyamide homopolymer having the same structure as the amide in the polyethylene oxide block polyamide copolymer can be used. When the blend melted at a high temperature at the time of molding is cooled to form a phase structure, the polyamide homopolymer first solidifies into a fibrous form, followed by the polyethylene oxide block polyamide copolymer. Due to the compatibility with the polyamide homopolymer, it can be effectively arranged and the volume resistivity can be effectively reduced.
That is, a blend of polyethylene oxide block nylon 12 copolymer and nylon 12, a blend of polyethylene oxide block nylon 6 copolymer and nylon 6 and the like can effectively reduce the volume resistivity.

  As described above, the content of melamine cyanurate is 15% to 40% by weight with respect to the total weight of the flame-retardant belt. This range is because if the amount is less than 15% by weight, there is a problem that sufficient flame retardancy cannot be imparted to the belt. On the other hand, if it exceeds 40% by weight, the molded belt becomes brittle. Because there is. The content of melamine cyanurate is preferably 20% to 35% by weight.

Since the melamine cyanurate has a decomposition temperature of 300 ° C. or higher, it exists in powder form up to this temperature range. For this reason, if the temperature is about the usage environment of the image forming apparatus or the like, bleeding or blooming from the belt surface does not occur, and the photoreceptor is not contaminated.
In addition, melamine cyanurate is a nitrogen-based flame retardant, pyrolyzing with combustion heat, replacing oxygen with nitrogen-based gas and hindering combustion. It is possible to obtain a belt that has little environmental impact without worrying about occurrence.

The flame-retardant belt has a polyester thermoplastic elastomer as a main component. As a result, it is possible to achieve both moderate elasticity and flexibility as a belt and moderate hardness, and it is possible to realize excellent durability even when it is repeatedly bent. Polyester thermoplastic elastomers have good impact resistance, heat resistance, and moldability, and also have good oil resistance, so that they are not easily altered by toner or the like, and are less susceptible to photoconductor contamination. Furthermore, since the colorability is also good, a white belt or a belt colored in another color can be obtained by combining it with the action of melamine cyanurate as an extender pigment. When a white belt is used, particularly when used as an intermediate transfer belt, toner adhesion can be easily observed, which is preferable for evaluating the cleaning performance. In the case of a white belt, it is preferable not to add an additive that becomes black when carbon black or the like is blended.
In addition, the moldability can be further improved by adding a lubricant or the like. Therefore, it is possible to obtain a flame retardant seamless belt which has an appropriate flexibility in the thickness direction, is hardly stretched in the length direction, and is excellent in vibration. The polyester-based thermoplastic elastomer is preferably 60% by weight or more, more preferably 65% by weight or more of the total polymer component.

As the polyester-based thermoplastic elastomer, those having an appropriate grade such as hardness, elastic modulus, moldability and the like can be used according to the required characteristics of the belt, for example, polyester polyether-based, polyester polyester-based, etc. A plurality of types may be mixed.
Since the cation is captured in the vicinity of the ether bond of the polyether or in the vicinity of the ester bond of the polyester, the salt is not easily oozed out of the system, and good conductivity can be expressed. In addition, in the polyether polyester system, this molecular chain, which is a soft segment, has a small change in elastic modulus between a low-temperature and low-humidity state and a high-temperature and high-humidity state and is stable. Become.

  The polyester-based thermoplastic elastomer is preferably a copolymer composed of a hard segment made of polyester having an aromatic ring and a low melting point soft segment made of polyether and / or polyester. In addition, the melting point when the high polymer is formed with only the high melting point polyester component is 150 ° C. or higher, and the melting point or the softening point when measured only with the low melting point soft segment component is 80 ° C. or lower. A polyester-based thermoplastic elastomer is preferred.

  As high-melting point polyester segment constituents having the above aromatic ring, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid or esters thereof and glycols having 1 to 25 carbon atoms and The ester-forming derivative can be used. In addition, it is preferable that terephthalic acid is 70 mol% or more of the total acid component as an acidic component of the high melting point polyester segment constituent component. Examples of the glycol having 1 to 25 carbon atoms include ethylene glycol, 1,4-butanediol, and ester-forming derivatives thereof. Other acid components can also be used as necessary, but these amounts are preferably 30 mol% or less, more preferably 25 mol% or less of the total acid components.

  Examples of the low melting point soft segment made of the polyether in the present invention include polyalkylene ether glycols such as poly (ethylene oxide) glycol and poly (tetramethylene oxide) glycol. Poly (tetramethylene oxide) glycol is preferable from the viewpoint of high melting point and moldability, and a molecular weight of 800 to 1500 is particularly preferable from a low temperature characteristic, and is preferably 15% to 75% of the total weight of the polyester-based thermoplastic elastomer. .

  Lactones are preferably used as the low melting point soft segment made of polyester in the present invention. As the lactone, caprolactone is most preferable, but enan lactone, caprylolactone, and the like can also be used as other lactones, and two or more of these lactones can be used in combination. The copolymerization ratio between the aromatic polyester and the lactone can be selected depending on the application, but the standard ratio is 97 / 3-5 aromatic polyester / lactone by weight ratio. / 95, more generally in the range of 95/5 to 30/70.

  In addition to the polyester-based thermoplastic elastomer, a polymer component such as a known thermoplastic elastomer or thermoplastic resin can be used alone or in combination with the thermoplastic composition as necessary.

  A phosphoric acid ester having a melting point of 80 ° C. or higher can also be contained so that the weight ratio of phosphorus to the total weight is 0.1 wt% or more and 0.4 wt% or less. By using melamine cyanurate and the above phosphoric acid ester together, the flame retardancy can be further improved without increasing the amount of melamine cyanurate more than necessary, and the seamless belt has good strength and a short afterflame time. Can be obtained.

  Moreover, in order to improve mechanical strength, you may mix | blend fillers, such as a calcium carbonate, a silica, a clay, a talc, barium sulfate, diatomaceous earth. Furthermore, in the range that does not cause liberation of additives from the belt surface, transfer to contact materials such as bleeding, blooming, and photoreceptor contamination, and in the range that does not adversely affect flame retardancy and conductivity. Acids, fatty acids such as lauric acid, softening agents such as cottonseed oil, tall oil, asphalt substances, and paraffin wax may be blended. As a result, the hardness and flexibility of the belt can be adjusted appropriately. Furthermore, you may mix | blend anti-aging agents, such as imidazoles, amines, and phenols.

The volume resistivity of the flame retardant belt is in the range of 10 ^6.0 Ω · cm to 10 ^12.0 Ω · cm as described above, and preferably 10 ^6.0 Ω · cm to 10 ^11.0. Ω · cm. Thereby, it can be used for a wide range of applications as a conductive seamless belt such as an intermediate transfer or a sheet material conveying belt. The above range is used because if the resistance value is smaller than 10 ^6.0 Ω · cm, the current easily flows, so that it may be difficult to hold the charge, and the device may not function as a member of the image forming apparatus. is there. On the other hand, if it is larger than 10 ^12.0 Ω · cm, there is a problem that a high voltage is required for processes such as transfer, charging, and toner supply, and the efficiency is lowered, which makes it unsuitable for practical use.

In order to adjust the volume resistivity in the range of 10 ^6.0 Ω · cm to 10 ^12.0 Ω · cm, the salt having the anion described in Chemical Formula 1 is adjusted to 0 with respect to 100 parts by weight of the total polymer component. 0.01 parts by weight to 3 parts by weight, preferably 0.05 parts by weight to 2.7 parts by weight.
When the salt having an anion described in Chemical Formula 1 is used, the effect of reducing the resistance value of the belt by adding a small amount is excellent. However, if the amount is less than the above range, it is difficult to adjust the resistance value. On the other hand, even if the content is larger than the above range, the effect of reducing the electrical resistance value is almost saturated, and it is difficult to further reduce the electrical resistance, an electric field is applied when the belt is used, and salt is caused by contact with the photoreceptor. This is to cause bleeding. Further, this is because it becomes easy to stick to the die lip and sizing die of the mold during the extrusion molding of the belt, and the molding becomes difficult.

The flame-retardant belt has a volume resistivity of ρ _V (t = 0 hr.) Immediately after voltage application when a voltage is applied at a measurement environment of 23 ° C., a relative humidity of 55%, a sample thickness of 250 μm, and an applied voltage of 1000 _V , continuous 5 When the volume resistivity after applying the time voltage is ρ _V (t = 5 hr.), The relationship of log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) ≦ 0.5 is satisfied. Preferably it is.
If the above relationship is satisfied, even when a voltage is continuously applied, the volume resistivity does not increase, and a flame-retardant belt having excellent electrical characteristics can be obtained. ρ _V (t = 5 hr.) and ρ _V (t = 0 hr.) may be the same, and (log ₁₀ ρ _V (t = 5 hr.) − log ₁₀ ρ _V (t = 0 hr.)) The smaller the value is, the better. Considering the measurement accuracy and the current technical level, the lower limit of the value of (log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.)) Is 0.01 or more, or 0.1 or more, Or it becomes about 0.3 or more.

  The flame retardant belt includes a conductive master batch in which a salt having a polyether block as a main component and an anion represented by Chemical Formula 1 is blended in an amount of 1 wt% to 20 wt%, a flame retardant, A material obtained by melt-kneading a thermoplastic composition mainly composed of a polyester-based thermoplastic elastomer with an extruder is used as a material, and the material is extruded from an annular die and formed into a belt shape along a sizing die. .

Since the salt having an anion described in Chemical Formula 1 is kneaded in advance into a copolymer having a polyether block to form a conductive master batch, the salt is present in the copolymer having a polyether block. In addition, salt movement can be suppressed even during continuous energization, resistance rise can be reduced, resistance to environmental influences such as temperature and humidity, and variations in electrical resistance and voltage dependence can be reduced. Moreover, when the compounding quantity of the said salt in a composition is a small amount, adjustment of resistance value becomes easy.
By kneading and extruding the conductive masterbatch, flame retardant, and thermoplastic composition, the salt is uniformly dispersed together with the copolymer having a polyether block, and there is little variation in resistance value. A seamless belt having moderate elasticity and flame retardancy can be easily obtained.

  In the conductive master batch, if the amount of the salt having the anion described in Chemical Formula 1 is less than 1% by weight, it is difficult to obtain the effect of making the conductive master batch. On the other hand, if it exceeds 20% by weight, it becomes difficult to knead the salt. The kneading can be performed by a known method such as a Banbury mixer or a kneader, but is preferably performed by drawing a strand with a twin-screw extruder. In the conductive masterbatch, the copolymer having a polyether block is preferably 50% by weight or more of the total polymer component, and may be 100% by weight. In addition, a polymer such as a copolymer having a plurality of types of polyether blocks and a polyester-based thermoplastic elastomer may be blended in the conductive masterbatch.

The flame retardant and the thermoplastic composition mainly composed of the polyester-based thermoplastic elastomer are put into the extruder as a flame retardant masterbatch kneaded in advance, and the material is disposed vertically from the annular die. Preferably it is extruded.
The thermoplastic composition melted by the extruder can be introduced into an annular die, extruded from the die lip, and contact cooled and cured in a sizing die provided downstream of the die lip in a molten state to be formed into a belt shape. The sized continuous cylindrical molded product is further cut by a cutting device provided downstream, and a belt having a predetermined width can be obtained. The melting temperature in the extruder is 200 ° C to 270 ° C, preferably 200 ° C to 250 ° C, more preferably 220 ° C to 240 ° C. Specifically, a conductive masterbatch, a flame retardant masterbatch, and a polyester thermoplastic elastomer are dry blended and kneaded by a twin screw extruder to obtain a belt material. Thereafter, the strands are drawn, pelletized and dried. The pellets are put into a hopper of a single screw extruder and extruded. By forming by extrusion molding in this way, for example, a large-diameter thin belt having a diameter of 168 mm, a thickness of 250 μm, and a width of 400 mm can be easily formed.

  The melt coming out of the die lip is not affected by gravity by being pushed out in the vertical direction, the residual strain is reduced, and it is guided to the sizing die while maintaining the cylindrical state, thereby improving the dimensional accuracy. In particular, the direction of extrusion is preferably vertically downward.

  Flame retardants such as melamine cyanurate are pre-kneaded into polymers such as polyester-based thermoplastic elastomers to form a flame retardant masterbatch, which improves the dispersibility of the flame retardant and may occur during belt molding Unevenness due to aggregation of flame retardants can be eliminated. Even with a method that does not use a flame-retardant masterbatch, the occurrence of flaws can be prevented by increasing the kneading effect, but the masterbatch method is preferred because it is easier. In the flame retardant masterbatch, the flame retardant is preferably blended in an amount of 30 wt% to 70 wt%, and further 40 wt% to 60 wt%.

As is clear from the above description, in the conductive member of the present invention, the conductive layer has a phase structure composed of a continuous phase, a discontinuous phase of two or more phases, a first discontinuous phase and a second discontinuous phase. And a polymer constituting the first discontinuous phase in which the salt dissociable into the cation and the anion is unevenly distributed in the discontinuous phase and the salt dissociable in the cation and the anion is unevenly distributed Is higher in affinity with a salt capable of dissociating into a cation and an anion than a polymer constituting the cation. For this reason, it is possible to suppress the outflow of the salt out of the system when an electric field is applied while increasing the degree of freedom of the salt in the first discontinuous phase and maintaining a low electric resistance. It is possible to prevent a rise in resistance at the time of transition or continuous electrodynamics. Furthermore, since salt is unevenly distributed in the first discontinuous phase, it is hardly affected by the environment such as temperature and humidity, and due to ionic conduction, variation in electric resistance and voltage dependency are small.

  In addition, even if the electric field continues to be applied, it is suppressed that the salt migrates and appears on the surface, or the resistance value rises. Therefore, it is possible to use a salt with excellent conductivity, and the salt with excellent conductivity can be used. Excellent conductivity can be obtained even in a small amount. Therefore, in-plane variation of resistance value and environmental dependency are small, and resistance increase during continuous energization can be reduced. In addition, problems such as bleed, bloom, photoconductor contamination and migration contamination do not occur, and influences on other physical properties such as compression set and hardness can be reduced as much as possible.

  Therefore, in the image forming apparatus such as a copying machine, a facsimile machine, and a printer having a conductive member made of a roller or a belt according to the present invention, the resistance is increased during continuous energization, although the resistance is mainly reduced by ionic conduction. In addition, the electrical dependency is less dependent on the environment and the in-plane variation of rollers and belts is small, so that not only a uniform image can be obtained, but also a larger power source is required to cover the resistance value change. The power consumption of the entire image forming apparatus can be reduced. Further, the range to be controlled by changing the applied voltage can be made smaller, and the apparatus can be made simpler. Furthermore, since the control system can be simplified and environmental tests during development can be reduced, the time and cost required for development can be suppressed. In addition, a stable image can be obtained over a long period of time while the burden on surrounding members is small.

Further, in the flame-retardant belt, a polyester thermoplastic elastomer as a main component, a flame retardant melamine cyanurate, a salt having the above anion, and a copolymer having a polyether block are added at each specified weight. Since it contains and shape | molds, the flame retardance excellent in the belt can be provided, without affecting the volume resistivity of a belt. In addition, it is possible to obtain a belt having a smooth extruded skin, free from contamination of the photoreceptor, and having excellent drivability and durability due to appropriate elasticity. In particular, since the resistance increase during continuous energization is small, when used as an intermediate transfer belt of an image forming apparatus, the range to be controlled by changing the transfer voltage can be made smaller, and a good image can be obtained. The mechanism of the forming apparatus can be simplified.
In addition, since melamine cyanurate is a nitrogen-based flame retardant, it is possible to obtain a belt having a small influence on the environment without worrying about generation of toxic gas or the like due to halogen. Furthermore, since melamine cyanurate also acts as an extender pigment, the belt can be freely colored. In particular, a white belt can be obtained by adjusting additives and the like, and therefore can be suitably used as an intermediate transfer belt.

Embodiments of the present invention will be described below.
FIG. 1 shows a conductive roller 10 according to a first embodiment made of a conductive member for an image forming apparatus of the present invention. The conductive roller 10 includes a cylindrical metal core 12 having conductivity and the conductive layer 11 on the surface side of the core 12, and the core 12 is provided in a hollow portion of the cylindrical conductive layer 11. Press-fit and install.

The structure of the ion conductive polymer composition forming the conductive layer 11 is shown in the schematic diagram of FIG. The ion conductive polymer includes a continuous phase 1, a first discontinuous phase 2, and a second discontinuous phase 3. The three phases have a sea-island structure. The first discontinuous phase 2 and the second discontinuous phase 3 exist substantially uniformly in the continuous phase 1, and the first discontinuous layer 2 exists so as to surround the second discontinuous phase 3 .

FIG. 3 shows a morphology (10 μm per side) of the conductive polymer composition observed in a phase mode with an atomic force microscope (AFM) scanning probe microscope (SPM). In FIG. 3, the continuous phase 1 exhibits the lightest color, the first discontinuous phase 2 exhibits the darkest color, and the second discontinuous phase 3 exhibits a medium color density. In the figure, the dark portion has a high elastic modulus, and the light portion has a low elastic modulus.
Further, as shown in FIG. 3, the volume fraction is such that continuous phase 1> second discontinuous phase 3> first discontinuous phase 2.

In order to exhibit the sea-island structure as shown in FIG. 2 and FIG. 3, the type and amount of the polymer of each phase are defined, and the amount of salt to be added and the addition method are defined.
To the ion conductive polymer composition, 0.01 to 20 parts by weight of a salt dissociable into a cation and an anion is added with respect to 100 parts by weight of the total polymer, and the first discontinuous phase 2 is added. The salt is preferentially distributed and distributed unevenly, and almost no salt is added to the second discontinuous phase 3 and the continuous phase 1.

  The polymer of the first discontinuous phase 2 has a higher affinity for the dissociable salt than the polymer constituting the continuous phase 1, and the polymer constituting the continuous phase 1 does not add a dissociable salt. The affinity with the dissociable salt is higher than that of the polymer constituting the second discontinuous phase 3. That is, the affinity of each phase with the polymer salt is such that first discontinuous phase 2> continuous phase 1> second discontinuous phase 3.

  Specifically, as shown in Example 2 described later, for example, an EO-PO-AGE copolymer (EO: PO: AGE = 90: 4: 6 (molar ratio) is used as a polymer constituting the first discontinuous phase 2. )) 10 parts by weight, 63 parts by weight of low nitrile NBR as the polymer constituting the continuous phase 1, and low polarity ozone resistance as the polymer constituting the second discontinuous phase 3 with almost no dissociable salt added 27 parts by weight of EPDM rubber is used. That is, the affinity with the dissociable salt is EO-PO-AGE copolymer> low nitrile NBR> EPDM.

The volume resistivity of the EO-PO-AGE copolymer of the first discontinuous phase 2 is ρ _V1 , the volume resistivity of the low nitrile NBR of continuous phase 1 is ρ _V2 , and the volume resistivity of EPDM of the second discontinuous phase 3 is When the the ρ _{V3, log 10} ρ _V1 is 7.9, _{log 10} ρ _V2 is 10.2, _{log 10} ρ _V3 is 14.8, the value of _{(log 10 ρ V2 -log 10 ρ} V1) 2 .3.
The weight ratio of the polymer constituting the first and second discontinuous phases 2 and 3 to the polymer constituting the continuous phase 1 is 37:63.

1.1 parts by weight of lithium-bis (trifluoromethanesulfonyl) imide, which is a salt having an anion having a fluoro group and a sulfonyl group, as a salt dissociable into a cation and an anion added to the conductive polymer ing. This salt has a conductivity of 4.0 mS / cm measured in a PC / DME mixed solvent (volume fraction 1/2) at a salt concentration of 0.1 mol / liter at 25 ° C. Moreover, it mix | blends without passing through the medium which consists of a low molecular weight polyether compound with a molecular weight of 10,000 or less and a low molecular weight polar compound.
In this embodiment, lithium-bis (trifluoromethanesulfonyl) imide is used as a salt that can be dissociated into a cation and an anion. Trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonyl) imide, lithium-tris (trifluoromethanesulfonyl) methane, or the like may be used.

  The conductive polymer composition comprises 9 parts by weight of carbon black as a filler, 5 parts by weight of zinc oxide, 1 part by weight of stearic acid, 1.5 parts by weight of powdered sulfur as a vulcanizing agent, and two types of vulcanization accelerators. Each consists of a vulcanized rubber composition blended with 1.5 parts by weight and 0.5 parts by weight.

The conductive roller 10 having the conductive layer 11 formed from the conductive polymer composition described in FIG. 1 is manufactured by the following method.
First, a dissociable salt and an EO-PO-AGE copolymer are kneaded at 60 ° C. for 3 minutes using a kneader, and low nitrile NBR, EPDM, and other various compounding agents are added to the obtained kneaded product. It mix | blends and again knead | mixes with an open roll, a closed kneader, etc. at 60 degreeC for 4 minutes, and produces a conductive polymer composition.
Note that the dissociable salt and the EO-PO-AGE copolymer may be mixed uniformly using a mixer such as a Henschel mixer or a tumbler without using a kneader.

This conductive polymer composition is put into a single screw extruder having a diameter of 60 mm, extruded into a hollow tube shape at 60 ° C. and preformed, and the raw rubber tube is cut into a predetermined size to obtain a preform. When this preform is put into a pressurized steam vulcanizing can and foamed, the chemical foaming agent is gasified and foamed, and vulcanized at a temperature at which the rubber component crosslinks (15 to 70 minutes at 160 ° C.). Obtained vulcanized rubber tube.
Vulcanization conditions are measured with a curast meter or the like, and are appropriately adjusted with a 95% torque rise time t95 [minute] as a guide.
In order to reduce the photoreceptor contamination and compression set, it is desirable to set the conditions so that a sufficient vulcanization amount can be obtained.

  After preparing the core metal 12 and applying the hot melt adhesive to the outer peripheral surface thereof, the core metal is inserted into the vulcanized rubber tube obtained above, heated and bonded, and then the surface is polished to form the conductive layer 11. Finished to the target dimensions. The dimensions of the conductive layer 11 of the conductive roller 10 are an inner diameter of 6 mm, an outer diameter of 14 mm, and a length of 218 mm.

The conductive layer 11 has a compression set value of 17% measured at a measurement temperature of 70 ° C. and a measurement time of 24 hours in the vulcanized rubber and thermoplastic rubber permanent strain test method described in JIS K 6262. The volume resistivity described in JIS K 6911 measured under a voltage of 100 V is ^109.0 [Ω · cm].

The conductive roller 10 has an electric resistance value of 10 ^7.7 Ω at an applied voltage of 1000 V, a resistance value when a constant voltage of 1000 V is continuously applied for 96 hours in an environment of 23 ° C. and a relative humidity of 55%. R [Ω] was measured, and the increase in resistance value Δlog ₁₀ R = log ₁₀ R (t = 96 hr.) − Log ₁₀ R (t = 0 hr.) Was set to 0.10. Further, the resistance value R [Ω] under the conditions of 10 ° C. relative humidity 15%, 32.5 ° C. relative humidity 90% was measured, and the environmental dependency of the resistance value Δlog ₁₀ R = log ₁₀ R (10 ° C. relative humidity _{15%) -} log 10 values of R (32.5 ° C. 90% RH) is set to 0.9.

  The conductive layer 11 of the conductive roller 10 manufactured by the above method includes the continuous phase 1, the first discontinuous phase 2, and the second discontinuous phase 3, and the first discontinuous phase 2 and the second discontinuous phase 3. To surround. As described above, the high-performance salt capable of controlling the morphology and reducing the resistance value with a small amount is unevenly distributed in the first discontinuous phase 2 mainly composed of the EO-PO-AGE copolymer. It is possible to obtain a low electrical resistance value necessary for practical use while preventing the salt from moving out of the product when added and the resistance increase during continuous energization.

Therefore, while maintaining low electrical resistance, changes in the electrical resistance due to the environment and changes due to continuous use are reduced, and variations in the electrical resistance due to the roller parts are reduced, so that stable and good images can be formed. A gentle conductive roller can be obtained. Therefore, it is suitable for a developing roller, a charging roller, a transfer roller, and the like. In particular, it is suitable as a conductive roller for color copiers or color printers that require high image quality.
In addition, it can also be set as the foaming roller which mix | blends a foaming agent, has a foaming ratio whose foaming magnification is 100% or more and 500% or less, and whose hardness measured with the type E durometer described in JIS K6253 is 60 degrees or less.

  In addition, the conductive layer 11 is provided with a second discontinuous phase 3 in which almost no salt is distributed, and the second discontinuous phase 3 is present so as to be surrounded by the first discontinuous phase 2 in which the salt is unevenly distributed. Therefore, the volume fraction of the first discontinuous phase 1 in which the salt is unevenly distributed can be suppressed without significantly impairing the conductivity. Thereby, even if the addition amount of the salt and the polymer of the first discontinuous phase 1 that actively distributes the salt is reduced, a low volume resistivity and a product resistance value of the roller can be obtained as a whole. In addition, since the salt having an anion having a fluoro group and a sulfonyl group used as a salt capable of dissociating into the cation and the anion is expensive, the cost is increased by reducing the amount of these salts added. Can be suppressed.

Examples of the conductive roller, reference examples and comparative examples were prepared and measured for physical properties.
About Examples 1-8, Reference Examples 1-3 , and Comparative Examples 1-10, kneading | mixing, extrusion, a vulcanization | cure, molding process each compounding material of Table 1 ~ Table 4 by the method similar to the said embodiment. The conductive roller was manufactured by polishing. A conductive roller for a transfer roller mounted on a Laser Jet 4050 laser beam printer manufactured by Hewlett-Packard Company.

In parallel with this, the rubber removed from the kneader is extruded by a roller head extruder and formed into a sheet shape, which is vulcanized in a vulcanizer at 160 ° C for an optimal time, and then the thickness is about 2 mm. This was sliced to obtain a vulcanized rubber slab sheet for volume resistivity (volume resistivity value) evaluation. Tables 1 to 4 show the evaluation results performed using these rollers and rubber slab sheets and various evaluations as rollers described later.
In addition, each implementation obtained by measuring while increasing the temperature from −100 ° C. to 100 ° C. at 10 ° C./min using a differential scanning calorimeter DSC2910 of TA Instruments Japan Co., Ltd. The glass transition temperatures (Tg [° C.]) of the polymers used in the examples and comparative examples are also shown in the table.

(Examples 1 to 4, Reference Examples 1 and 2 )
Examples 1 to 4 and Reference Example 2 use EO-PO-AGE copolymer as the polymer constituting the first discontinuous phase, and Reference Example 1 uses epichlorohydrin rubber, which contains cation and anion. Lithium-bis (trifluoromethanesulfonyl) imide of salt 1 which is a dissociable salt or lithium-tris (trifluoromethanesulfonyl) methane of salt 2 was unevenly distributed. Low nitrile NBR was used as the continuous phase, and Examples 1 to 4 used EPDM as the second discontinuous phase. A foaming roller was used except for Example 2. The conductivity measured in a PC / DME mixed solvent of salt 2 (volume fraction 1/2) at a salt concentration of 0.1 mol / liter at 25 ° C. is 3.6 mS / cm.

( Reference Example 3 )
Epichlorohydrin rubber (50 phr), NBR, calcium carbonate, hydrotalcite, zinc white and stearic acid were mixed and kneaded in a closed kneader preheated to 120 ° C. A thiourea crosslinking agent (vulcanizing agent 2) master batch of epichlorohydrin rubber (10 phr) prepared in advance while kneading and a vulcanization accelerator (vulcanization accelerator 3) for the thiourea crosslinking agent were added and dynamically crosslinked. Crosslinking proceeded while looking at the kneading torque chart, and kneading was once completed near the torque peak. Subsequently, the mixture was cooled to 50 ° C., and sulfur, vulcanization accelerator 1 and vulcanization accelerator 2 were mixed with a kneader to obtain a dynamic cross-linking composition. This was extruded into a tube shape and preformed in the same manner as in Examples 1 to 4 and Reference Examples 1 and 2, and the tube was cut and vulcanized at 160 ° C. for 10 to 70 minutes to obtain a conductive layer. It was.

(Examples 5 to 8 )
In Examples 5 to 8 , an EO-PO-AGE copolymer is used as a polymer constituting the first discontinuous phase, and salts 3 to 6 which are salts dissociable into a cation and an anion are respectively added thereto. It was unevenly distributed. Salt 3 is potassium-bis (trifluoromethanesulfonyl) imide, salt 4 is hexyltrimethylammonium-bis (trifluoromethanesulfonyl) imide, and salt 5 is 1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonyl) imide (abbreviated). EMI-TFSI) and salt 6 is 1-ethyl-3-methylimidazolium tetrafluoroborate (abbreviated EMI-BF4).
About others, it was the same as that of Example 2, and it was set as the solid roller.
The salt 4 is a quaternary ammonium salt of the trimethyl type (three of R1 to R4 are methyl groups) whose cation is represented by the chemical formula 2, the salt 5 is an imidazolium salt represented by the chemical formula 3, and one of R5 and R6 is A methyl group and the other is an ethyl group.

(Comparative Examples 1-6)
In Comparative Example 1, no salt capable of dissociating into a cation and an anion was used. Comparative Examples 2 and 3 have a two-phase structure of a continuous phase composed of low nitrile NBR and a discontinuous phase composed of EPDM, and lithium-bis (trifluoromethanesulfonyl) imide which is a salt dissociable into a cation and an anion in the continuous phase. (Salt 1) was unevenly distributed. Comparative Examples 4 and 5 have a single-phase structure composed of one kind of polymer, and lithium-bis (trifluoromethanesulfonyl) imide (salt 1) which is a salt dissociable into a cation and an anion in one phase. Was formulated. Comparative Example 6 uses EO-PO-AGE copolymer as the polymer constituting the first discontinuous phase in the same manner as in Examples 1 to 4 and Reference Example 2, and can be dissociated into a cation and an anion. The salt, lithium-bis (trifluoromethanesulfonyl) imide (salt 1), was unevenly distributed, but EPDM having a high volume resistivity and a low affinity with the salt was used for the continuous phase. Comparative Examples 1 and 2 were foam rollers.

(Comparative Examples 7 to 10)
Comparative Examples 7 to 10 have a two-phase structure of a continuous phase composed of low nitrile NBR and a discontinuous phase composed of EPDM. Lomethanesulfonyl) imide, hexyltrimethylammonium-bis (trifluoromethanesulfonyl) imide of salt 4, EMI-TFSI of salt 5 and EMI-BF ₄ of salt 6 were unevenly distributed.

The lithium-bis (trifluoromethanesulfonyl) imide of the salt 1 is disclosed in JP-B-1-38781, JP-A-9-173856, JP-A-3117369, JP-A-11-209338, JP-A-2000-86617, JP-A-2001. -139540, JP-A-2001-288193 and the like were synthesized by a conventionally known method. In the embodiment of the present invention, specifically, 3M Fluorad HQ-115 (manufactured by Sumitomo 3M Limited) was used.
As the salt 2 lithium-tris (trifluoromethanesulfonyl) methane, one synthesized by a conventionally known method such as US Pat. No. 5,554,664, Japanese Patent Application Laid-Open No. 2000-219692, and Japanese Patent Application Laid-Open No. 2000-226392 was used. Specifically, it was synthesized by the following method. A methyllithium / ether solution was added to the flask and cooled to −55 ° C., and trifluoromethanesulfonyl chloride was added dropwise with vigorous stirring, and then the temperature was gradually raised and reacted for a long time under boiling reflux. Thereafter, after release to room temperature, hydrochloric acid was added while cooling. Subsequently, the filtrate obtained by separating the crystallized lithium chloride and lithium hydroxide by filtration was extracted with ether, and further washed with saturated brine. Crystals obtained by adding anhydrous magnesium sulfate to the organic layer and drying, followed by filtration under reduced pressure through a membrane filter having a pore size of 0.2 μm, removing the solvent from the filtrate under reduced pressure, and then adding toluene to perform azeotropic dehydration. Dried.
The potassium-bis (trifluoromethanesulfonyl) imide of the salt 3 is the same as the lithium-bis (trifluoromethanesulfonyl) imide of the salt 1 and is synthesized by a conventionally known method as described in the above publication. It was. Specifically, those manufactured by Morita Chemical Co., Ltd. and sold as one of lithium compounds and fluorine compounds for capacitors were used. Hereinafter, an example of a method for obtaining lithium-bis (trifluoromethanesulfonyl) imide of salt 1 and potassium-bis (trifluoromethanesulfonyl) imide of salt 3 will be described. First, acetonitrile, potassium fluoride, and trifluoromethanesulfonylamide (CF ₃ SO ₂ NH ₂ ) are added to a four-necked flask, and the reaction vessel is immersed in a 40 ° C. hot water bath, and trifluoromethanesulfonyl fluoride ( CF ₃ SO ₂ F) was introduced, the reaction solution was filtered, and the filtrate was concentrated under reduced pressure to obtain salt 3 of potassium-bis (trifluoromethanesulfonyl) imide. This potassium-bis (trifluoromethanesulfonyl) imide is added to a flask containing concentrated sulfuric acid, heated and melted, and then distilled under reduced pressure to obtain bis (trifluoromethanesulfonyl) imidic acid (HN (SO ₂ CF ₃ ) _2. ) Was dissolved in pure water, reacted with lithium carbonate and filtered, and the filtrate was concentrated to obtain lithium-bis (trifluoromethanesulfonyl) imide of salt 1. This method is disclosed in Japanese Patent Application Laid-Open No. 2001-288193 as an inexpensive and efficient method for producing salt 1. By producing by this method, the potassium-bis (trifluoromethanesulfonyl) imide of the salt 3 can be produced as an intermediate substance in the production process of the lithium-bis (trifluoromethanesulfonyl) imide of the salt 1, so that the cost is reduced. There are advantages.
The salt 4 hexyltrimethylammonium-bis (trifluoromethanesulfonyl) imide was manufactured by Koei Chemical Industry Co., Ltd.
1-ethyl-3-methylimidazolium-bis (trifluoromethanesulfonyl) imide (EMI-TFSI) of salt 5 is manufactured by Stella Chemifa Corporation, 1-ethyl-3-methylimidazolium-tetrafluoroborate of salt 6 (EMI-BF ₄ ) was also made by Stella Chemifa Corporation.

As the EO-PO-AGE copolymer and epichlorohydrin rubber, those previously kneaded with a dissociable salt were used. In the combined system of carbon black and EPDM, carbon black was previously kneaded into EPDM and used as a master batch. In Reference Example 2 , carbon black was kneaded in advance into NBR and used as a master batch. Vulcanization accelerator 1 was dibenzothiazyl disulfide, vulcanization accelerator 2 was tetramethylthiuram monosulfide, and foaming agent 1 was 4,4′-oxybis (benzenesulfonylhydrazide).

Volume resistivity ρ _V1 of the polymer constituting the first discontinuous phase in which salts dissociated into cation and anion are unevenly distributed, volume resistivity ρ _{V2 of} the polymer constituting the continuous phase, dissociation into cation and anion The measurement of the volume resistivity ρ _V3 of the polymer constituting the second discontinuous phase in which possible salt is not unevenly distributed was performed without adding salt.
For example, in Example 1 or Example 2, 100 parts by weight of ZSN8030, 9 parts by weight of Seest 3, 5 parts by weight of silver candy R, 1 part by weight of stearic acid 4931, 1.5 parts by weight of powdered sulfur, Noxeller DM The volume resistivity of a composition containing 1.5 parts by weight and 0.5 parts by weight of Noxeller TS was measured. The applied voltage during measurement was 100 V, and the measurement environment was 23 ° C. and relative humidity 55%.

(Measurement of volume resistivity)
The measurement sheet produced as described above was measured under a constant temperature and humidity condition of 23 ° C. and a relative humidity of 55% using an ultrahigh resistance microammeter R-8340A manufactured by Advantest Corporation. The measuring method was according to the measuring method of volume resistivity (volume specific resistance value) described in JIS K6911, and the applied voltage at the time of measurement was 100V. The common logarithm is displayed in the table. The first reference is an embodiment described later of the conductive belt of Reference Examples 4-9 of the present invention and Comparative Examples 11 to 16 is used as the resulting conductive belt, the circumferential direction four points of the belt X Measured in the same manner as described above at a total of 20 points in the longitudinal direction, and the average value of log ₁₀ ρ _V [Ω · cm] is shown in the table.

(Roller resistance value)
As shown in FIG. 4, the conductive layer 41 through the cored bar 42 is abutted and mounted on a φ30 aluminum drum 43 and connected to the + side of the power supply 44 in an atmosphere at a temperature of 23 ° C. and a relative humidity of 55%. The tip of the lead wire having resistance r (100Ω to 10 kΩ) was connected to one end surface of the aluminum drum 43 and the tip of the lead wire connected to the negative side of the power source 44 was connected to one end surface of the core metal 42 to conduct electricity. The conductive roller 40 was indirectly rotated by applying a load F of 500 g to both ends of the core metal 42 and rotating the aluminum drum 43 while applying a voltage of 1000 V between the core metal 42 and the aluminum drum 43. At this time, resistance measurement was performed 36 times in the circumferential direction, and the average value was obtained. The value of the internal resistance was adjusted so that the significant figure of the measured value was as large as possible according to the level of the resistance value of the roller. In the apparatus shown in FIG. 4, when the applied voltage is E, the roller resistance value R is R = r × E / V−r, but this time the term −r is regarded as minute, and R = r × E / V. The roller resistance value R was calculated from the detected voltage V applied to the internal resistance r. In the table, the average logarithmic value of the roller resistance value is used.

(Measurement of environmental dependency of roller resistance)
The apparatus shown in FIG. 4 is placed in each measurement environment, and the roller electricity is applied under the condition of 10 ° C. relative humidity 15% (LL condition) or 32.5 ° C. relative humidity 90% (HH condition) under an applied voltage of 1000V. The resistance value R (Ω) was measured, and the environmental dependence was calculated according to the equation: Δlog ₁₀ R = log ₁₀ R (10 ° C. relative humidity 15%) − log ₁₀ R (32.5 ° C. relative humidity 90%). In the table, the common logarithm values are used. It is not preferable that this value exceeds 1.7.

(Roller resistance unevenness)
Using the apparatus shown in FIG. 4, the conductive roller is rotated by applying a load F of 500 g to both ends of the core metal at a temperature of 23 ° C. and a relative humidity of 55%, and rotating the aluminum drum at a rotation speed of 30 rpm. In this state, when an applied voltage of 1000 V was applied, the circumferential unevenness (ratio of (maximum value of electrical resistance in the circumferential direction / minimum value of electrical resistance in the circumferential direction)) within one circle was determined. The circumferential unevenness is 1.0 to 1.3, more preferably 1.0 to 1.2, and still more preferably 1.0 to 1.15.

(Resistance increase during continuous energization)
Regarding [ Examples 1 to 8, Reference Examples 1 to 3 ] and [Comparative Examples 1 to 10].
A constant voltage of 1000 V was continuously applied to the roller for 96 hours in an environment of 23 ° C. and a relative humidity of 55% in the same state as when the roller resistance value [Ω] was measured. At this time, the roller resistance value R (t = 0 hr.) Immediately after voltage application and the roller resistance value R (t = 96 hr.) After 96 hours application were measured in the same manner as described above, and these values were measured. The amount of increase in resistance during continuous energization was calculated as follows: Δlog ₁₀ R (t = 96 hr. −0 hr .) [Ω] = log ₁₀ R (t = 96 hr .) − Log ₁₀ R (t = 0 hr.). Numerical values are shown in Tables 1-4. Since the rotation speed of the aluminum drum is 30 rpm and the diameter is 30 mmφ, the linear velocity during rotation is 94 mm / min.

(Compression set)
Using the test piece obtained by cutting the conductive roller obtained above with a width of 10 mm parallel to the end face, according to the vulcanized rubber and thermoplastic rubber permanent strain test method described in JIS K6262, a measurement temperature of 70 ° C., a measurement time The measurement was carried out at a compression rate of 25% for 22 to 24 hours. If this compression set value exceeds 30%, the dimensional change when it becomes a roller becomes too large, and there is a high possibility that it becomes unsuitable for practical use.

(Photoconductor contamination test)
In Examples 1 to 8, Reference Examples 1 to 3 , and Comparative Examples 1 to 10, the test was performed by the following method.
In a state where the vulcanized rubber slab sheets of Examples , Reference Examples, and Comparative Examples are pressed against the photoreceptor set in the cartridge (cartridge type C4127X) of Laser Jet 4050 type laser beam printer manufactured by Hewlett-Packard Company, 32. Store for 2 weeks at 5 ° C and 90% relative humidity. Thereafter, the vulcanized rubber slab sheet was removed from the photoconductor, halftone printing was performed with the printer using the photoconductor, and whether or not the printed material was stained was examined according to the following criteria.
○: No contamination as long as the printed product is visually observed. △: Mild contamination (contamination with no problem in use that can be removed to the extent that it cannot be seen visually by imprinting within 5 sheets)
×: Severe contamination (contamination that reveals abnormalities by visual inspection of printed matter even when 5 or more sheets are imprinted)
In addition, about Reference Examples 4 to 9 and Comparative Examples 11 to 16 relating to the conductive belt which is a first reference embodiment of the present invention to be described later, a section of the obtained conductive belt and a laser manufactured by Fuji Xerox Co., Ltd. Evaluation was performed in the same manner as described above, using a beam printer DocuPrint 180 and a photoconductor set in the cartridge (product code CT350035). However, the storage conditions were 45 ° C. and 80% relative humidity.

(Measurement of hardness)
About the electroconductive roller, the hardness under the load of 500 g was measured using the type E durometer described in JIS K6253 (durometer E hardness). However, for the solid roller, the load was 1000 g.

As shown in Tables 1 and 2, the conductive rollers of Examples 1 to 8 and Reference Examples 1 to 3 have a dissociable salt dissociated in the required first non-continuous phase. In addition to being excellent in electrical characteristics, problems such as migration contamination did not occur. In particular, the electrical resistance was less dependent on the environment, and the resistance increase during continuous energization was small. Also, the foam roller was good because the resistance increase during energization was small.
In particular, as in Example 5 , when potassium bis (trifluoromethanesulfonyl) imide is used as a salt capable of dissociating into a cation and an anion, it can be obtained with fewer steps than lithium-bis (trifluoromethanesulfonyl) imide. Therefore, the cost can be reduced, and the potassium cation is slightly heavier than the lithium cation, so that the increase in resistance during continuous energization can be further reduced.
When a quaternary ammonium salt is used as a salt capable of dissociating into a cation and an anion as in Example 6 , sufficient conductivity can be obtained while increasing the cation. The increase in resistance during continuous energization could be reduced.
When EMI-TFSI is used as a salt capable of dissociating into a cation and an anion as in Example 7 , the resistance increase during continuous energization can be reduced and the environmental dependency of the resistance value can be reduced. It was very good.
As in Example 8 , when EMI-BF ₄ was used, relatively good results were obtained.

On the other hand, as shown in Tables 3 and 4, since Comparative Example 1 did not contain a dissociable salt, the volume specific resistance value and the roller resistance value were slightly higher for the transfer roller described above. Further, as compared with Examples 1 to 8 and Reference Examples 1 to 3 , the resistance dependency of the conductive roller on the environment is slightly increased.
In Comparative Examples 2, 3, and 7 to 10, since dissociable salts were unevenly distributed in the continuous phase, the increase in resistance during continuous energization was not suitable.
Since Comparative Examples 4 and 5 used a salt that can be dissociated in a one-phase system, the resistance increase during continuous energization was not suitable.
In Comparative Example 6, since EPDM, which is substantially insulating, was used for the continuous phase, the volume specific resistance value and the roller resistance value were high. Further, since the compatibility between the EPDM and the EO-PO-AGE copolymer is poor, the circumferential unevenness is very large.

  Moreover, FIG. 3 mentioned above was the morphology which observed Example 2 in the phase mode in the scanning probe microscope (SPM) of the atomic force microscope (AFM) type. The morphology of Comparative Example 3 (10 μm per side) is shown in FIG. Comparative Example 3 is composed of one continuous phase and one discontinuous phase, and the dissociable salt is unevenly distributed in the continuous phase.

  Further, FIG. 6 shows resistance changes during continuous energization of Example 1 and Comparative Example 2. The horizontal axis is the energization time, and the vertical axis is the roller resistance value. In Example 1 and Comparative Example 2, the roller resistance values in the initial state are almost the same. However, as shown in FIG. Only a slight increase.

7 and 8 show a first reference embodiment, in which a conductive belt 13 formed using the conductive polymer composition of the reference embodiment of the present invention is used as a transfer belt.
The conductive belt 13 is stretched by two pulleys 14 and carries and conveys a sheet material 16 such as paper on a linear portion 15 on the upper side of the rotating conductive belt 13. The toner image formed above is transferred to the sheet material 16.

Although the said electroconductive belt 13 is not limited only to the following forms, it consists only of the electroconductive layer 21 formed from the electroconductive polymer composition of one layer of seamless belt shape. As shown in FIG. 8, the conductive layer 21 is composed of one continuous phase 1 ′ and one first discontinuous phase 2 ′. The continuous phase 1 ′ and the first discontinuous phase 2 ′ It has a sea-island structure.
Only the first discontinuous phase 2 ′ has a salt dissociable into a cation and an anion, and the polymer constituting the first discontinuous phase 2 ′ can be dissociated more than the polymer constituting the continuous phase 1 ′. It has high affinity with various salts.

  Specifically, 30 parts by weight of a resin-type antistatic agent made of a polyethylene oxide block nylon 12 copolymer is used as a polymer constituting the first discontinuous phase 2 ′ in which dissociable salts are unevenly distributed, and the continuous phase 1 ′ is used. As a constituent polymer, 100 parts by weight of a polyester-based thermoplastic elastomer composed of a soft segment made of polyether and a hard segment made of polyester is used.

When the volume resistivity of the resin-type antistatic agent constituting the first discontinuous phase is ρ _V1 and the volume resistivity of the polyester-based thermoplastic elastomer constituting the continuous phase is ρ _V2 , log ₁₀ ρ _V1 is 9.0, log. ₁₀ [rho _V2 is 13.4, and 4.4 the values of _{(log 10 ρ V2 -log 10 ρ} V1). The weight ratio of the polymer constituting the first discontinuous phase 2 ′ to the polymer constituting the continuous phase 1 ′ is 23:77.

  As a salt dissociable into a cation and an anion, 1.5 parts by weight of lithium-bis (trifluoromethanesulfonyl) imide, which is a salt having an anion having a fluoro group and a sulfonyl group, is used. This salt has a conductivity of 4.0 mS / cm measured at a salt concentration of 0.1 mol / liter at 25 ° C. in a PC / DME mixed solvent (volume fraction 1/2), and has a molecular weight of 10,000 or less. It is blended without a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound.

The conductive belt 13 is manufactured by the following method.
The detachable salt and the resin-type antistatic agent are dry blended using a tumbler. The dry blend is immediately fed into a twin screw extruder, kneaded at 170 to 210 ° C. for 2 minutes, and then cooled to be pelletized. The pellets of the polyester-based thermoplastic elastomer thus obtained are dry blended in the same manner as described above, and again kneaded at 210 to 270 ° C. for 2 minutes using a twin screw extruder and cooled. Conductive polymer composition pellets are made. The conductive polymer composition pellets are formed into a belt shape by an extruder.

The conductive belt 13 has a volume resistivity of 10 ^9.6 [Ω · cm] described in JIS K6911 measured under an applied voltage of 100V.

The conductive belt 13 has a volume resistivity ρ _V [Ω · cm when a constant voltage of 1000 V is continuously applied to a sample having a thickness of 0.25 mm for 5 hours in an environment of 23 ° C. and a relative humidity of 55%. ], And the value of increase in volume resistivity Δlog ₁₀ ρ _V = log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) Is set to 0.36. Further, volume resistivity ρ _V [Ω · cm] under conditions of 10 ° C. relative humidity of 15% and 32.5 ° C. relative humidity of 90% was measured, and the environmental dependency of volume resistivity Δlog ₁₀ ρ _V = log ₁₀ The value of ρ _V (10 ° C. relative humidity 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity 90%) is set to 1.4.

The conductive belt 13 includes a conductive layer 21 in which a salt that can be dissociated into a cation and an anion is unevenly distributed in the first discontinuous phase 2 ′, and a salt that can reduce a resistance value with a small amount as a salt to be added. In addition, since the polymer used for each phase is selected appropriately, it is necessary for practical use while preventing the salt from moving out of the system when the electric field is applied or the increase in resistance during continuous energization. A low electrical resistance value can be obtained. Moreover, it has moderate flexibility in the thickness direction, but hardly stretches in the length direction. And, in the case of a non-chlorine and non-bromine of the composition as in the Reference Examples 4-9 which will be described later, environment may be, a very excellent conductivity seamless belt practical.

The belt of the first reference embodiment is a transfer belt, but can also be used as, for example, an intermediate transfer belt, a fixing belt, a developing belt, a conveyance belt, and the like used in an image forming apparatus. In particular, when a white belt is used, toner adhesion can be easily visually checked, so that it is suitable for evaluation of cleaning performance and can be suitably used as an intermediate transfer belt.

Reference Examples 4 to 9 and Comparative Examples 11 to 16 of the conductive belt were produced and measured for physical properties.
Each compounding material described in Tables 5 to 7 was compounded and kneaded using the tumbler and twin-screw extruder by the method described above, and then extruded by a resin extruder, and the inner diameter was 168 mm, the average thickness was 0.25 mm, A conductive belt for a transfer belt having a width of 350 mm was produced. Tables 5 to 7 show the evaluation results and various evaluations as the belt described above. In addition, the Tg [° C.] of each polymer obtained by measurement in the same manner as the values in Tables 1 to 4 are also shown in the table.

( Reference Examples 4 to 9 )
From a polyethylene oxide block nylon 12 copolymer having a very high affinity between a cation and an anion dissociable salt as used in the present invention as a polymer constituting a discontinuous phase, and a polyether ester amide copolymer. The resin-type antistatic agent obtained was unevenly distributed with lithium-bis (trifluoromethanesulfonyl) imide, which is a salt dissociable into a cation and an anion. A polyester-based thermoplastic elastomer composed of a soft segment made of polyether and a hard segment made of polyester was used as the continuous phase. A master batch with the above-described resin-type antistatic agent was prepared and used so that the concentration of the salt such as lithium-bis (trifluoromethanesulfonyl) imide was 5 wt%. In addition, since the value of ρ _{V2 in} the data of Comparative Example 12 and the volume specific resistance value of the composition show moderately low values, the thermoplastic elastomer (perprene) used in these reference examples is It can be seen that the salt used in the invention has a certain affinity.

(Comparative Examples 11-16)
Comparative Example 11 was prepared by dissolving 20 wt% of lithium-bis (trifluoromethanesulfonyl) imide of salt 1 in dibutoxyethoxyethyl adipate into a polyester-based thermoplastic elastomer (polyether-polyester block copolymer perprene P90BD). Blended. At this time, 2.5 parts by weight of an adipate ester ion conductivity-imparting agent in which 20 wt% of salt 1 was dissolved in dibutoxyethoxyethyl adipate was used, whereby the amount of salt 1 was 0.5 parts by weight.
In Comparative Example 12, lithium-bis (trifluoromethanesulfonyl) imide of salt 1 was directly dispersed in one phase of a polyester-based thermoplastic elastomer without using a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound. .
In Comparative Examples 13 to 16, in the same manner as Comparative Example 12, each of the above salts 3 to 6 was added to one phase of the polyester-based thermoplastic elastomer without using a medium composed of a low molecular weight polyether compound or a low molecular weight polar compound. Used directly dispersed.

  The resin-type antistatic agent 1 has a polyethylene oxide block nylon 12 copolymer as a main component. The resin-type antistatic agent 2 contains a polyether ester amide copolymer as a main component.

(Volume specific resistance environment dependence)
In the reference examples and comparative examples of the conductive belt, 100 V was applied in the same manner as described above even in an environment of 10 ° C. relative humidity 15% (LL environment) and 32.5 ° C. relative humidity 90% (HH environment). The volume resistivity of the conductive belt at the time was measured.
Then, the environmental dependency of volume resistivity: Δlog ₁₀ ρ _V (LL-HH) [Ω.cm] = log ₁₀ ρ _V (10 ° C., 15% rh.) − Log ₁₀ ρ _V (32.5 ° C., 90 % Rh.), The numerical value of the environment dependency is calculated, and the value is shown in Tables 5-7. It is not preferable that this value exceeds 1.7.

  The volume specific resistance value and the photoreceptor contamination test were measured by the method described in the measurement method for the conductive roller.

(Resistance increase during continuous energization)
Regarding [ Reference Examples 4 to 9 ] and [Comparative Examples 11 to 16].
A digital ultra-high resistance micrometer manufactured by Advantest Corporation at a certain point in a conductive belt having a thickness of 0.25 mm in the same condition as when measuring volume resistivity in an environment of 23 ° C. and relative humidity of 55%. A constant voltage of 1000 V was continuously applied for 5 hours using an ammeter R-8240A. In this case, the volume resistivity of the belt immediately after the voltage application _{ρ V (t = 0hr.)} , The value of the volume of 5 hours after application of the belt resistivity _{ρ V (t = 5hr.)} , As described above Using these values, the resistance increase during continuous energization: Δlog ₁₀ ρ _V (t = 5-0 hr.) [Ω · cm] = log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) was calculated. Numerical values are shown in Tables 5-7.

(In-plane unevenness)
The measurement of the in-plane unevenness of the conductive belt is the measurement of the volume resistivity (volume resistivity value) of the conductive belt described above, with respect to the volume resistivity value of 20 points obtained in one belt, A value obtained by dividing the maximum value by the minimum value was calculated and listed in Tables 5 to 7. Thus, it can be seen that the belts in the examples, reference examples, and comparative examples are very uniform with almost no unevenness. On the other hand, this value can be about 2 to 10 for a carbon conductive belt, and about 100 for a large belt.

As shown in Table 5, in Reference Examples 4 and 5 , since the dissociable salt is unevenly distributed in the required first discontinuous phase, both of them have excellent electrical characteristics and cause problems such as migration contamination. There wasn't. In particular, the electrical resistance was less dependent on the environment, and the resistance increase during continuous energization was small.

As shown in Table 6, Reference Example 6 is a salt that can be dissociated into a cation and an anion, and instead of lithium-bis (trifluoromethanesulfonyl) imide of salt 1, potassium-bis (trifluoromethanesulfonyl) of salt 3 ) Same as Reference Example 4 except that imide was used. In salt 3, since the cation is a potassium ion heavier than the lithium ion, the increase in resistance during continuous energization could be further reduced. Further, as described above, the salt 3 is less expensive than the salt 1, but since almost the same resistance value can be obtained with the same blending amount, the cost can be reduced. Furthermore, the environmental dependence of the volume resistivity value could be further reduced.
Reference Example 7 was the same as Reference Example 4 except that salt 4 was used in place of salt 1 as a salt capable of dissociating into a cation and an anion. It has been found that it has excellent characteristics in resistance increase during continuous energization, photoconductor contamination, and the like.
Reference Example 8 was the same as Reference Example 4 except that salt 5 was used instead of salt 1 as a salt capable of dissociating into a cation and an anion. As in Reference Example 6 , since sufficient conductivity can be obtained while increasing the cation, the increase in resistance during continuous energization can be reduced. Furthermore, the environmental dependence of the volume resistivity value could be further reduced.
Reference Example 9 was the same as Reference Example 4 except that salt 6 was used instead of salt 1 as a salt capable of dissociating into a cation and an anion. Although the environmental dependency etc. are slightly inferior to those of the other reference examples, it was found that the energization increase is small as compared with Comparative Example 16, which is very excellent.

On the other hand, Comparative Example 11 uses a salt that can be dissociated in a one-phase system, and such a salt is dispersed using a medium composed of a low molecular weight polar compound. It was unsuitable.
In Comparative Example 12, the resistance increase during continuous energization was large, and the environmental dependency was slightly large.
Since Comparative Examples 13 to 16 are one-phase systems as in Comparative Example 12, the resistance increase during continuous energization was large. Further, Comparative Example 14 was unsuitable due to contamination of the photoreceptor.

FIG. 9 shows an image forming apparatus for a color printer provided with an intermediate transfer belt 33 formed of a flame-retardant seamless belt according to the second embodiment of the present invention. The color printer includes transfer rollers 30a and 30b, a charging roller 31, a photoconductor 32, an intermediate transfer belt 33, a fixing roller 34, four color toners 35 (35a, 35b, 35c, and 35d), and a mirror 36.

  When an image is formed by this color image forming apparatus, first, the photoconductor 32 rotates in the direction of the arrow in the drawing, and the photoconductor 32 is charged by the charging roller 31, and then the laser 37 is passed through the mirror 36. Is exposed to the non-image portion of the photosensitive member 32 and is neutralized, and the portion corresponding to the image portion is charged. Next, the toner 35a is supplied onto the photoreceptor 32, and the toner 35a adheres to the charged image line portion to form a first color image. This toner image is transferred onto the intermediate transfer belt 33 by applying an electric field to the primary transfer roller 30a. Similarly, each color image of the toners 35b to 35d formed on the photoconductor 32 is transferred onto the intermediate transfer belt 33, and a full color image composed of four color toners 35 (35a to 35d) is formed on the intermediate transfer belt 33. Is once formed. The full-color image is transferred onto a transfer target (usually paper) 38 by applying an electric field to the secondary transfer roller 30b, and passes through the fixing roller 34 heated to a predetermined temperature, thereby transferring the transfer target 38. Is fixed to the surface. When performing double-sided printing, the transfer target 38 that has passed through the fixing roller 34 is reversed inside the printer, and the above image forming process is repeated to form an image on the back side again.

The intermediate transfer belt 33 composed of the flame-retardant seamless belt of the present invention contains a polyester-based thermoplastic elastomer as a main component and contains melamine cyanurate in a proportion of 25% by weight with respect to the total weight. Polyethylene oxide which is a copolymer having a polyether block containing 1.2 parts by weight of lithium-bis (trifluoromethanesulfonyl) imide which is a salt having an anion described in 1. A block nylon 12 copolymer (glass transition temperature Tg of −57 ° C.) was contained at a ratio of 30 parts by weight with respect to 100 parts by weight of the polyester-based thermoplastic elastomer, and the volume resistivity was 10 ^9.6 Ω · cm. The thermoplastic composition is kneaded using a twin screw extruder and then molded by extrusion.

The volume resistivity immediately after voltage application is ρ _V (t = 0 hr.) When a voltage is applied at a measurement environment of 23 ° C., a relative humidity of 55%, a sample thickness of 250 μm, and an applied voltage of 1000 _V. When the rate is ρ _V (t = 5 hr.), Log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) = 0.36.

Also, volume resistivity ρ _V (10 ° C., relative humidity 15%) in a low temperature and low humidity environment (10 ° C., relative humidity 15%) and volume resistivity ρ in a high temperature, high humidity environment (32.5 ° C., relative humidity 90%). The relationship with _V (32.5 ° C. relative humidity 90%) is log ₁₀ ρ _V (10 ° C. relative humidity 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity 90%) = 1.6. Yes.

  In this embodiment, the weight of the copolymer having a polyether block is 19.2 times the weight of the salt having the anion described in Chemical Formula 1. Note that lithium-bis (trifluoromethanesulfonyl) imide is blended without a medium composed of a low molecular weight polyether compound having a molecular weight of 10,000 or less or a low molecular weight polar compound.

  The intermediate transfer belt 33 of the present invention has excellent flame retardancy, does not contaminate the photoreceptor, and has an appropriate flexibility in the thickness direction, but is difficult to extend in the length direction, and is environmentally friendly. It is a seamless belt that has little impact and is very practical. In addition, the flame resistance is imparted to the belt without affecting the volume resistivity, resistance variation in the surface is small and environmental dependency is small, resistance rise during continuous energization is small, and extruded skin is also Smooth. Therefore, the flame-retardant seamless belt of the present invention is used without being restricted by the use state even in the case where the belt is placed in a high voltage and high temperature environment in an image forming apparatus such as a copying machine, a facsimile machine, or a printer. And a uniform image can be obtained.

Hereinafter, for example, a method for producing a flame-retardant seamless belt that can be used as the intermediate transfer belt will be described in detail.
First, a conductive masterbatch containing a copolymer having a polyether block as a main component and containing 5% by weight of the salt having the anion described in Chemical Formula 1 is prepared, and a polyester-based thermoplastic elastomer and melamine are prepared. A flame retardant masterbatch containing the same amount of cyanurate is prepared. The conductive masterbatch obtained here, the flame retardant masterbatch, and the polyester-based thermoplastic elastomer are kneaded in a required amount by a twin-screw extruder, and a thermoplastic composition for belt molding in which each material is blended in a specified amount. A material consisting of things is obtained.
The kneading temperature of the conductive master batch is 200 ° C. to 270 ° C., preferably 200 ° C. to 250 ° C., the kneading time is preferably 1 minute to 20 minutes, and the kneading temperature of the flame retardant master batch is also 200 ° C. to 270 ° C., preferably Is preferably 200 ° C. to 250 ° C., and the kneading time is preferably 1 minute to 20 minutes.

  FIG. 10 shows the belt manufacturing apparatus 50. The belt manufacturing apparatus 50 includes a hopper 51 for charging materials, an extruder 52 for melting and extruding the charged materials, and a crosshead die having a circular die structure in which the central axis of the extruder 52 and the central axis of the die are perpendicular to each other. 53, a gear pump 54 that is disposed between the extruder 52 and the crosshead die 53 and adjusts the amount of extrusion, an inside sizing 55 that is a sizing mold for shaping the extruded ring B from the inner peripheral surface side, A take-up machine 56 for picking up the formed annular object B in the vertical direction and an automatic cutting machine 57 for cutting the continuously formed annular object B into a predetermined length are provided. The crosshead die 53 is configured to push the melt vertically downward from the die lip 53a of the annular die.

  The belt molding material is introduced from the hopper 51 of the extruder 52 and melted at 200 ° C. to 270 ° C., preferably 200 ° C. to 250 ° C., and the melt is adjusted to the crosshead die 53 while adjusting the extrusion amount with the gear pump 54. Send it in. The melt is extruded from the die lip 53a of the annular die of the crosshead die 53 in an annularly downward direction at an extrusion speed of 133 mL / min. The annular material B extruded from the die lip 53a is cooled along the inside sizing 55 at 70 ° C to 100 ° C, shaped into a belt shape, taken down vertically by the take-up machine 56, and taken to a predetermined length by the automatic cutting machine 57. To produce flame-retardant seamless belts.

Although the flame retardant belt of the second embodiment is used as an intermediate transfer belt, it can also be used as a fixing belt, a developing belt, a conveying belt, etc. used in an image forming apparatus or the like. In particular, when a white belt is used, toner adhesion can be easily visually checked, so that it is suitable for evaluation of cleaning performance and can be suitably used as an intermediate transfer belt.

In the said 2nd Embodiment, although it is set as the structure of only 1 layer shape | molded using the said thermoplastic composition, you may have an at least 1 layer of coating layer in the outer peripheral surface side. The coating layer such as a coating layer may have a multilayer structure such as a two-layer or three-layer structure, and can be on the outer peripheral surface side and / or the inner peripheral surface side of the seamless belt.

  As the polyester thermoplastic elastomer, a polyester polyether type or a polyester polyester type can be used. Moreover, if it has the anion of Chemical formula 1, it will not be limited to the said salt, You may change the kind etc. of a cation. The copolymer having a polyether block can also be appropriately changed. In addition to the manufacturing method by extrusion molding, it is possible to mold by injection molding or the like, and it is possible to mold without using a masterbatch.

Hereinafter, examples and comparative examples of the flame-retardant belt of the second embodiment will be described in detail.
(Example 9 )
Lithium-bis (trifluoromethanesulfonyl) imide, which is a salt having the anion described in Chemical Formula 1 above, is converted into a copolymer having a polyether block (Irgastat P16, manufactured by Ciba Specialty Chemicals: polyethylene oxide block nylon 12) The polymer (glass transition temperature Tg is −57 ° C.) is dry blended at a ratio of 5% by weight, charged into a hopper of a twin screw extruder, and kneaded at a setting of 210 ° C. to conduct electricity. A sex masterbatch was obtained. The actually measured value of the resin temperature at this time was 230 ° C.

  Melamine cyanurate (MC640: manufactured by Nissan Chemical Co., Ltd.) is dried to a polyester thermoplastic elastomer (Perprene P90BD, manufactured by Toyobo: Polyester polyether system (glass transition temperature Tg of −56 ° C.)) to a ratio of 50% by weight. After blending, this was put into a hopper of a twin screw extruder and kneaded at a setting of 210 ° C. to obtain a flame retardant masterbatch. The actually measured value of the resin temperature at this time was 230 ° C.

  Polyester thermoplastic elastomer, conductive masterbatch, and flame retardant masterbatch pellets, lithium-bis (trifluoromethanesulfonyl) imide content copolymer with polyether block and polyester thermoplastic 1.2 parts by weight with respect to 100 parts by weight of the total polymer component as a total with the elastomer, the content of the copolymer having a polyether block is 30 parts by weight with respect to 100 parts by weight of the polyester-based thermoplastic elastomer, Dry blending was performed at such a ratio that the content of melamine cyanurate was 25% by weight of the total weight. This was put into a hopper of a twin screw extruder and kneaded at 210 ° C. to obtain a belt forming material. The actually measured value of the resin temperature at this time was 230 ° C.

  The produced belt forming material is put into the hopper of the extruder of the manufacturing apparatus shown in FIG. 10 and melted by operating the extruder. An annular die having an inner diameter of 185 mm and a gap of 0.5 mm at a die temperature of 235 ° C. The melt was extruded in the vertical direction. Then, it is cooled at 80 ° C by following inside sizing with an outer diameter of 170mm, solidified and molded, pulled vertically downward at a take-up speed of 1m / min, and continuously fire-retardant by cutting to 400mm width with an automatic cutting machine Sex seamless belt. The inner diameter of the belt = 169.5 mm, the average thickness = 250 μm, and the width = 400 mm.

The performance of the belt of Example 9 is shown below. Each performance was measured by the method described later.
Volume resistivity: 10 to the 9.6th power (Ω · cm)
Resistance increase during continuous energization: 0.36
In-plane variation: 0.3
Environmental dependency: 1.6
Surface roughness: Rz = 1.1 μm
Image output: Good Flame resistance: ○

(Measurement of volume resistivity and increase in resistance during continuous energization)
Using an ultra high resistance microammeter R-8340A manufactured by Advantest Corporation, measurement was performed under constant temperature and humidity conditions of 23 ° C. and 55% relative humidity. The measurement method was in accordance with the volume resistivity measurement method described in JIS K 6911, and the applied voltage during measurement was 500V.
Regarding the resistance increase during continuous energization, the volume resistivity immediately after voltage application when the voltage was applied at a measurement environment of 23 ° C., a relative humidity of 55%, a sample thickness of 250 μm, and an applied voltage of 1000 V was expressed as ρ _V (t = 0 hr. ), And the volume resistivity after continuous voltage application for 5 hours was ρ _V (t = 5 hr.), And the value of log ₁₀ ρ _V (t = 5 hr.) − Log ₁₀ ρ _V (t = 0 hr.) Was evaluated. This value is preferably 0.5 or less.
FIG. 11 shows the change over time in volume resistivity during continuous energization for Example 9 , Example 10 and Comparative Example 17 below.

(In-plane variation)
The volume resistivity (Ω · cm) at 30 points in the surface of each belt was measured, and the maximum common logarithm value at 30 points−the common logarithm value at the minimum value = in-plane variation (measurement environment: 23 ° C. × 55 %, Measuring method: Hiresta, URS probe, 10 s, 250 V). The value of this in-plane variation is preferably 0.5 or less.

(Environment dependency)
Common logarithmic value of volume resistivity (Ω · cm) under LL condition (temperature 10 ° C, relative humidity 15%) and voltage resistance under HH condition (temperature 32.5 ° C, relative humidity 90%) when voltage of 500V is applied The difference in common logarithm of rate (Ω · cm) was defined as environment dependency. The environmental dependency value is preferably 2.5 or less, and more preferably 1.7 or less.

(Surface roughness)
The surface roughness Rz was measured based on JIS B0601. The measurement conditions were a cut-off value of 0.25 mm, a measurement length of 2.0 mm, and a measurement speed of 0.3 mm / s.

(Image out)
Each belt was mounted as an intermediate transfer belt of a full-color electrophotographic apparatus (Seiko Epson, Intercolor LP-8300C), an image output test was performed, and the transfer performance was evaluated.

(Flame retardance)
Flame retardancy test: VTM2
UL-94: According to the flammability test of plastic materials. The test was conducted by the method of “thin material vertical combustion test: VTM-0, VTM-1, VTM-2” using the thin film sample as a control. Those that have reached the level of VTM-2 are indicated as “◯”, and those that do not reach the level are indicated as “X”.

(Measurement of glass transition temperature)
The glass transition temperature Tg was measured using a differential scanning calorimeter DSC2910 manufactured by TA Instruments Japan Co., Ltd. while increasing the temperature from −100 ° C. to 100 ° C. at 10 ° C./min.

(Example 10 )
The copolymer having a polyether block was changed to a polyether ester amide copolymer (Pelestat NC6321 manufactured by Sanyo Chemical Industries, Ltd., glass transition temperature Tg of −43 ° C.). Others were the same as in Example 9 .
Volume resistivity: 10 to the 9.4th power (Ω · cm)
Resistance increase during continuous energization: 0.32
In-plane variation: 0.4
Environmental dependency: 2.1
Surface roughness: Rz = 1.6 μm
Image output: Good Flame resistance: ○

(Comparative Example 17)
A conductive masterbatch prepared by dry blending lithium-bis (trifluoromethanesulfonyl) imide with a polyester-based thermoplastic elastomer (Perprene P90BD) at a ratio of 10% by weight, and containing a copolymer having a polyether block. There wasn't.
The content of lithium-bis (trifluoromethanesulfonyl) imide was 0.5 parts by weight with respect to 100 parts by weight of the total polymer components. Others were the same as in Example 9 .

Volume resistivity: 10 to the power of 8.7 (Ω · cm)
Increase in resistance during continuous energization: 1.14
In-plane variation: 0.4
Environmental dependency: 2.0
Surface roughness: Rz = 1.6 μm
Image output: Good Flame resistance: ○

As shown in FIG. 11, in Examples 9 and 10 , even when a voltage was applied continuously for 5 hours, almost no increase in volume resistivity was observed, and it was confirmed that the electrical characteristics were very stable. It was. On the other hand, in Comparative Example 17, the volume resistivity increases as the energization time elapses. In particular, the resistance increase is large in the initial energization stage, and the resistance value is smaller when used in an image forming apparatus or the like. Control was necessary, and when the flame retardant belt of Comparative Example 17 was used, an increase in cost was expected.

As described above, Examples 9 and 10 were both excellent in evaluation results and confirmed to be flame retardant seamless belts excellent in practicality. On the other hand, Comparative Example 17 contained a copolymer having a polyether block and had a two-phase structure, and salt was not unevenly distributed in the island phase, so the resistance increase during continuous energization was very large.

It is the schematic of the conductive roller provided with the conductive layer formed from the conductive polymer of 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the conductive polymer composition which forms the said conductive layer. It is a figure which shows the phase structure (morphology) of the conductive polymer of FIG. It is the schematic of the measuring apparatus of the electrical property of rollers, such as a roller resistance value. It is a figure which shows the phase structure (morphology) of the conductive polymer which forms the conductive member of the comparative example 3. It is a graph which shows the resistance change at the time of continuous energization of the roller of Example 1 and Comparative Example 2. It is the schematic of the electroconductive belt formed using the electroconductive polymer composition of 1st reference embodiment of this invention. It is a schematic diagram which shows the structure of the conductive polymer composition of 1st reference embodiment. It is a typical front view of the color image forming apparatus provided with the flame-retardant belt of 2nd Embodiment of this invention. It is the schematic of the manufacturing apparatus of a flame-retardant belt. 10 is a graph showing changes over time in volume resistivity during continuous energization of materials used in Examples 9 and 10 and Comparative Example 17;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 'Continuous phase 2, 2' 1st discontinuous phase 3 2nd discontinuous phase 10 Conductive roller 11, 21 Conductive layer 12 Core metal 13 Conductive belt 33 Intermediate transfer belt 50 Belt manufacturing apparatus 51 Hopper 52 Extruder 53 Crosshead die 54 Gear pump 55 Inside sizing

Claims (29)

A conductive member for an image forming apparatus comprising a conductive roller and a conductive belt having a conductive layer formed from a conductive polymer composition containing an ion conductive additive salt,
The conductive layer is made discontinuous phase comprising a continuous phase and the first non-continuous phase and a second discontinuous phase, the continuous phase and the discontinuous phase and the sea - exhibits the island structure, said first non-contiguous The polymer constituting the phase has a higher affinity for the cation and anion dissociable salt than the polymer constituting the continuous phase, and the first discontinuous phase can be dissociated into a cation and an anion. While Ru is unevenly distributed salts, above the second discontinuous phase and the continuous phase hardly distribute the salt, and, first discontinuous phase affinity between the salt of the respective phases of the polymer> continuous Phase> second discontinuous phase, and the electrical resistance value (volume resistivity) of each phase is first discontinuous phase <continuous phase <second discontinuous phase,
Conductivity for an image forming apparatus, characterized in that it is formed from the polymer composition having a volume resistivity of 10 ⁴ to 10 ¹² [Ω · cm] described in JIS K6911 measured under an applied voltage of 100 V. Sexual member. When the volume resistivity of the polymer constituting the first discontinuous phase in which the salt capable of dissociating into the cation and the anion is unevenly distributed is ρ _V1 , and the volume resistivity of the polymer constituting the continuous phase is ρ _V2 , The conductive member for an image forming apparatus according to claim 1, wherein 0.2 ≦ log ₁₀ ρ _V2 −log ₁₀ ρ _V1 ≦ 5.   The weight ratio of the polymer constituting the discontinuous phase and the polymer constituting the continuous phase is (the polymer constituting the discontinuous phase: the polymer constituting the continuous phase) = (5:95) to (75: 25. The conductive member for an image forming apparatus according to claim 1 or 2, which is 25). Dissociable salt on Kihi ions and negative ions are in propylene carbonate (PC) / dimethyl carbonate (DME) based mixed solvent (volume ratio 1/2), the salt concentration of 0.1 mol / liter at 25 ° C. The conductive member for an image forming apparatus according to any one of claims 1 to 3, wherein the electrical conductivity measured in step 1 is 2.3 mS / cm or more . 5. The conductivity for an image forming apparatus according to claim 1 , wherein the salt capable of dissociating into a cation and an anion is a salt having an anion having a fluoro group or a sulfonyl group . Element. The conductive member for an image forming apparatus according to claim 5 , wherein the salt capable of dissociating into a cation and an anion is a lithium salt, a potassium salt, a quaternary ammonium salt, or an imidazolium salt . The conductive member for an image forming apparatus according to any one of claims 1 to 6 , wherein the conductive polymer composition is a vulcanized rubber composition or a thermoplastic elastomer composition . 8. The conductive member for an image forming apparatus according to claim 1 , wherein the polymer used for each phase has a glass transition temperature Tg of −40 ° C. or lower . The continuous phase contains low nitrile NBR, the first discontinuous phase contains a polyether polymer, the second discontinuous phase contains EPDM, and the salt is unevenly distributed in the polyether polymer of the first discontinuous phase. conductive member for an image forming apparatus according to any one of claims 1 to 8 are. The continuous phase low nitrile NBR, the first non-continuous phase polyether polymer, the second discontinuous phase contains an EPDM,
10. The volume fraction of the continuous phase, the first discontinuous phase, and the second discontinuous phase is set as follows: continuous phase> second discontinuous phase> first discontinuous phase. A conductive member for an image forming apparatus described in the item. The low nitrile NBR is blended at 90 to 50% by weight, the EPDM at 10 to 40% by weight, the polyether polymer at 0.5 to 25% by weight, and the salt at 0.1 to 2% by weight. Item 10. A conductive member for an image forming apparatus according to Item 10. As the polyether-based polymer, ethylene oxide (EO) - propylene oxide (PO) - An apparatus according to any one of claims 1 to 11 containing at least allyl glycidyl ether (AGE) copolymer Conductive member. The conductive polymer composition has a compression set measured at a measurement temperature of 70 ° C., a measurement time of 22 to 24 hours, and a compression rate of 25% in the vulcanized rubber and thermoplastic rubber permanent strain test method described in JIS K6262. The conductive member for an image forming apparatus according to any one of claims 1 to 12, wherein the size is 30% or less . The conductive member for an image forming apparatus according to claim 1, comprising a roller or a belt provided with the conductive layer . The resistance value R [Ω] when a constant voltage of 1000 V was continuously applied for 96 hours in an environment of 23 ° C. and a relative humidity of 55% was measured, and the increase in resistance value Δlog ₁₀ R = log ₁₀ R (t = 96 hr) The conductive member for an image forming apparatus according to claim 1, comprising a conductive roller having a value of .)-Log ₁₀ R (t = 0 hr.) Of 0.5 or less . The resistance value R [Ω] under the conditions of 10 ° C. relative humidity 15%, 32.5 ° C. relative humidity 90% was measured, and the environmental dependency of the resistance value Δlog ₁₀ R = log ₁₀ R (10 ° C. relative humidity 15% The conductive material for an image forming apparatus according to claim 1, comprising a conductive roller having a value of −log ₁₀ R (32.5 ° C. relative humidity of 90%) of 1.7 or less. Sexual member. The conductive layer is made of a conductive roller and / or a conductive belt having a foaming ratio of 100% to 500% and a hardness measured by a type E durometer described in JIS K6253 of 60 degrees or less. The conductive member for an image forming apparatus according to any one of claims 1 to 16. The volume resistivity ρ _V [Ω · cm] when a constant voltage of 1000 V was applied continuously for 5 hours to a sample having a thickness of 0.25 mm in an environment of 23 ° C. and a relative humidity of 55% was measured. increase the amount of rate _{△ log 10 ρ V = log 10} ρ V (t = 5hr.) - (. t = 0hr) log 10 ρ V values composed of a conductive belt is set to 0.5 or less of claims 1 to Item 18. A conductive member for an image forming apparatus according to any one of Items 14 and 17. Volume resistivity ρ _V [Ω · cm] under conditions of 10 ° C. relative humidity of 15% and 32.5 ° C. relative humidity of 90% was measured, and volume resistivity was dependent on the environment Δlog ₁₀ ρ _V = log ₁₀ ρ A conductive belt having a value of _V (10 ° C. relative humidity of 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity of 90%) of 1.7 or less is set to 1 to 14 , 17 to 17. The conductive member for an image forming apparatus according to claim 18. A conductive member for an image forming apparatus comprising a conductive layer formed from a conductive polymer composition containing an ion conductive additive salt,
The conductive layer includes a continuous phase and one or more discontinuous phases. The continuous phase and the discontinuous phase have a sea-island structure, and at least one of the discontinuous phases is a cation. And a first discontinuous phase in which a salt dissociable into anions is unevenly distributed, and the polymer constituting the first discontinuous phase is a salt capable of dissociating into the cation and anion than the polymer constituting the continuous phase. With high affinity,
The conductive polymer composition contains 95 to 50 parts by weight of a polyester-based thermoplastic elastomer with respect to 100 parts by weight of all polymer components, and melamine shear, which is a flame retardant with respect to 100% by weight of the polymer composition. In addition to containing 15% by weight to 40% by weight of nurate, and 0.01 parts by weight to 3 parts by weight of the salt having the anion described in Chemical Formula 1 below with respect to 100 parts by weight of the total polymer component. According to JIS K6911, a copolymer containing a polyether block and contained in a proportion of 5 to 50 parts by weight with respect to 100 parts by weight of the polyester-based thermoplastic elastomer was measured under an applied voltage of 100V. characterized in that the volume resistivity of the flame-retardant seamless belt is less 1.0 × 10 ⁶ Ω · cm or more 1.0 × ^{10 12} Ω · cm Conductive member for an image forming apparatus.
(Wherein X ₁ and X ₂ are functional groups having 1 to 8 carbon atoms, including C, F—, —SO ₂ —). The volume resistivity immediately after voltage application is ρ _V (t = 0 hr.) When a voltage is applied at a measurement environment of 23 ° C., a relative humidity of 55%, a sample thickness of 250 μm, and an applied voltage of 1000 _V. When the rate is ρ _V (t = 5 hr.),
log ₁₀ ρ _V (t = 5 hr.) − log ₁₀ ρ _V (t = 0 hr.) ≦ 0.5
The conductive member for an image forming apparatus according to claim 20 , comprising a belt satisfying the relationship: The copolymer having a polyether block has a glass transition temperature Tg of −40 ° C. or lower,
The weight of the copolymer having the polyether block in the belt material is 1.6 to 3333 times the weight of the salt with an anion according to the chemical formula 1 above. A conductive member for an image forming apparatus according to claim 1 . In the chemical formula 1, X ₁ − is C _n1 H _m1 F _{(2n1−m1 + 1)} —SO ₂ —, and X ₂ − is C _n2 H _m2 F _{(2n2−m2 + 1)} —SO ₂ — (n1, n2 is 1 And the integers m1 and m2 are integers of 0 or more)
Cation constituting the salt becomes an anion and pair according to Formula 1 is an alkali metal, 2A group including lithium, transition metals, according to claim 20 through claim 22 is any cation amphoteric metal The electroconductive member for image forming apparatuses of any one of Claims 1 . Low-temperature and low-humidity environment (10 ° C., 15% relative humidity) volume resistivity at a [rho _V (10 ° C. 15% RH), high temperature and high humidity environment (32.5 ° C., 90% relative humidity) volume resistivity at [rho _V ( 32.5 ° C. relative humidity 90%) satisfies the relationship log ₁₀ ρ _V (10 ° C. relative humidity 15%) − log ₁₀ ρ _V (32.5 ° C. relative humidity 90%) ≦ 2.5. The conductive member for an image forming apparatus according to any one of claims 20 to 23. The conductive member for an image forming apparatus according to any one of claims 20 to 24 , further comprising at least one coating layer on an outer peripheral surface side . Image forming apparatus comprising the conductive member according to any one of claims 1 to 25. A method for manufacturing a conductive member for an image forming apparatus according to any one of claims 1 to 19,
After kneading or uniformly mixing the salt that can be dissociated into the cation and the anion and the polymer constituting the first discontinuous phase in which the salt that can dissociate into the cation and the anion is unevenly mixed, A conductive polymer composition obtained by adding the polymer constituting the continuous phase and the polymer constituting the second discontinuous phase to the mixture and kneading again is prepared,
A method for producing a conductive member for an image forming apparatus, comprising producing a conductive member having a conductive layer by thermoforming the conductive polymer composition . 25. A method of manufacturing a conductive member for an image forming apparatus according to any one of claims 20 to 24, wherein:
A conductive masterbatch containing a copolymer having the polyether block and containing 1 wt% to 20 wt% of a salt having an anion represented by the following chemical formula 1, the flame retardant, and the polyester A material obtained by melt-kneading a thermoplastic composition containing a thermoplastic elastomer at a ratio of 50 wt% or more and 100 wt% or less with an extruder is extruded from an annular die and is placed along a sizing die A method for producing a conductive member for an image forming apparatus , comprising forming a seamless belt .
(Wherein X ₁ and X ₂ are functional groups having 1 to 8 carbon atoms, including C, F—, —SO ₂ —). The thermoplastic composition containing the flame retardant and the polyester-based thermoplastic elastomer is charged into the extruder as a pre-kneaded flame retardant masterbatch, and the material is extruded vertically from the annular die. Item 29. A method for producing a conductive member for an image forming apparatus according to Item 28 .