JP2006079016A - Semiconductive belt, image forming apparatus, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductive belt capable of obtaining steady, satisfactory transferability for a long time by maintaining durability, securely preventing a bleed phenomenon, effectively preventing deformation with time, an electric resistance change, etc., and ensuring the satisfactory capability of following a recording medium that is very rough, and the satisfactory shape of a nip between an image carrier and the belt itself, and to provide a semiconductive belt capable of obtaining steady, satisfactory transferability by preventing, for example, foreign matter from sticking to the surface of the belt or soiling it. <P>SOLUTION: The semiconductive belt is composed of one or more layers. The outermost layer comprises as the main constituent a thermosetting elastomer composition in which lubricant filler and conductive agent are dispersed. The surface D hardness of the outermost layer is 30 to 55, and the ten-point average surface roughness Rz of the outermost layer is 1.5 μm to 9.0 μm. In addition, the semiconductive belt includes an outermost layer and a base material inside the outermost layer. The base material is composed of an elastic body, and the outermost layer contains at least a fluorine-contained resin and graphite fluoride. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a semiconductive belt used for a transfer conveying belt or an intermediate transfer belt in an image forming apparatus using an electrophotographic system such as a copying machine or a printer, an image forming apparatus using the semiconductive belt, and an image forming apparatus. Regarding the method.

In an image forming apparatus using an electrophotographic method, first, a uniform charge is formed on the surface of an image carrier made of a photoconductive photoreceptor made of an inorganic or organic material, and the image signal is modulated with a laser beam or the like. After the electric image is formed, the electrostatic image is developed with a charged toner, and a visualized toner image is formed. Then, the toner image is electrostatically transferred to a recording medium such as a recording sheet via an intermediate transfer member, and fixed on a recording material to obtain a required reproduced image.
In particular, there is known an image forming apparatus that employs a system in which a toner image formed on the image carrier is primarily transferred to an intermediate transfer member, and a toner image on the intermediate transfer member is secondarily transferred to a recording sheet (for example, , See Patent Document 1).

  In the image forming apparatus employing the intermediate transfer body method, the materials used for the intermediate transfer body are polycarbonate resin, PVDF (polyvinylidene fluoride), polyalkylene phthalate, PC (polycarbonate) / PAT (polyalkylene terephthalate) blend. Proposals have been made to use conductive endless belts of thermoplastic resins such as materials, ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, PC / PAT blend materials, etc. 7).

  Further, as a semiconductive belt that can be used for an intermediate transfer belt, a transfer conveyance belt, and the like, a semiconductive belt in which a conductive filler is dispersed in a polyimide resin excellent in mechanical properties and heat resistance has been proposed (for example, (See Patent Documents 8 and 9.)

  However, the above-mentioned ones are inferior in toner transfer properties due to their high hardness, and in recent years, special papers with irregularities on the surface such as colored papers and embossed papers tend to be used. Since the followability to the toner is particularly bad, there is a problem that the transferability of the toner is extremely inferior.

  As a rubber belt material used in an image forming apparatus employing an intermediate transfer body method, an elastic belt with a reinforcing material formed by laminating a woven fabric such as polyester and an elastic member has been proposed. However, the elastic belt with a reinforcing material may cause a problem of color misregistration due to creep deformation of the belt material over time (see, for example, Patent Documents 10 and 11).

In order to increase the adhesion, a belt base material itself of an intermediate transfer belt (transfer conveyance belt) formed of an elastic material such as a flexible rubber material has already been provided. In general, when a rubber material is used as the belt base material, various chemicals are added to the rubber material in order to satisfy the properties such as ozone resistance, flame retardancy, and deterioration prevention. There is a concern that a so-called bleed phenomenon that precipitates on the surface of the conveyor belt may occur.
Therefore, when a flexible rubber material is used, a surface layer is provided to prevent bleeding.

Further, when an elastic body such as chloropyrene rubber in which carbon black or the like is dispersed is used as the semiconductive belt, the 10 ⁹ Ωcm level semiconductive resistance region is a region where resistance control is difficult. It is almost impossible to stably obtain a desired resistance value by adding ordinary conductive carbon black to a rubber material. It is difficult to stably produce elastic belt resistance variation within one digit (log Ωcm value), and when the in-plane variation in resistance is larger than one digit, the transfer voltage cannot be applied uniformly, so transfer image quality There is a problem that is not stable. Furthermore, the belt holds the recording medium, and a transfer voltage of 1 kV to 5 KV is applied to transfer the toner image to the recording medium. The applied voltage changes the resistance value of the belt material, and the recording medium There was a problem that the resistance value changed between a certain part and a part without a recording medium.

  For such a technical problem, if a mixed base material of chloroprene rubber and EPDM is used as a belt base material of a semiconductive belt, excellent ozone resistance and flame retardancy can be exhibited, and A technique that can effectively avoid the bleed phenomenon has already been provided (see, for example, Patent Document 1). Further, in Patent Document 1, if acetylene black, furnace black and acetylene black, or acetylene black and ketjen black are dispersed in the belt base material, fluctuations in electrical resistance over time can be suppressed. The point which can do is also disclosed.

However, the bleed phenomenon occurred when the surface of the conveying belt was in close contact with the surface of the image carrier for a long time. This is because when the coating layer of the conveyance belt is in close contact with the surface of the image carrier, a negative pressure between the two causes a low molecular oil component in the belt base material (EPDM and contained in various chemicals added during kneading). ) Is precipitated on the surface of the conveyor belt.
In order to avoid such problems, it is indispensable to dispose the image carrier and the transport belt through a contact / separation mechanism during non-image formation. Therefore, there is a technical problem that the apparatus configuration is complicated accordingly.

  In addition, as a belt material having a multi-layer structure, for example, a multi-layered endless belt made of plastic or a belt in which a polyolefin urethane layer is coated on a rubber belt surface has been proposed (for example, see Patent Documents 12 and 13). .)

  However, endless belts with a multilayer structure made of plastics have poor toner transferability due to the high hardness described above, and in recent years, special papers with irregularities on the surface such as colored paper and embossing have also been used. Therefore, since the following ability to paper is particularly bad, there is a problem that the transferability of toner is remarkably inferior. In addition, since the stress is large, the toner is easily destroyed, toner filming on the belt occurs, and the durability is inferior.

  Also, the belt with a polyolefin urethane layer, which is a thermoplastic elastomer, applied to the rubber belt surface is spray-coated with polyolefin urethane on the rubber belt, resulting in variations in the coating thickness in the surface direction. There is a drawback that the dimensional accuracy is poor. In addition, polyolefin-based urethane has a large amount of sag (deformation with time), and has a disadvantage that it adversely affects a copied image.

  In addition, in an image forming apparatus using the above semiconductive belt as an intermediate transfer member, it is known that there is a close relationship between the volume resistivity of the intermediate transfer member and the image quality of the toner image. Yes.

When the volume resistivity ρv of the intermediate transfer member is low (ρv <10 ⁸ Ωcm), toner scattering during transfer occurs significantly and the image quality is degraded. This is because when the volume resistivity of the intermediate transfer member is too low, the transfer electric field and the transfer current due to the primary transfer roll cause the transfer electric field to be easily applied to the area without the toner layer, so that the transfer area is expanded. This is considered to be because the toner is scattered and transferred due to the toner (for example, see Patent Document 14).

An intermediate transfer member of an image forming apparatus currently in practical use has a volume resistivity ρv having an intermediate value (10 ⁸ Ωcm ≦ ρv <10 ¹³ Ωcm). In such an image forming apparatus, the charged charge is appropriately attenuated by the semiconductivity of the intermediate transfer member. In other words, the average value of the volume resistivity of the intermediate transfer member is in a range where the charged charges are appropriately attenuated (volume resistivity is in an appropriate range), so that image formation is continuously performed without using a neutralizing member. Can do.

  However, even if the average value of the volume resistivity of the intermediate transfer member is in the appropriate range (the range in which the charged charge is appropriately attenuated), in the conventional intermediate transfer member, the above-described primary transfer roll is used. Due to the action of the transfer electric field and the transfer current, the transfer electric field is easily applied to the area without the toner layer, so that the transfer area widens, and the problem may occur that the toner is scattered and transferred due to the action. In order to obtain high-quality transfer image quality in recent years, there is a tendency for toner to use spherical toner having a small diameter, and the toner is easily moved by a transfer electric field because the toner is reduced in diameter and spherical. Therefore, the problem that the toner scatters easily occurs.

  Further, the conventional intermediate transfer member has the following problems. That is, when fillers such as carbon and metal compounds are dispersed in a polymer resin, the resistance variation in the intermediate transfer body due to the dispersed state of the filler is as large as about one digit or more, and a minute polymer between the filler and the filler. For example, the resistance of the intermediate transfer member may be lowered over time due to dielectric breakdown of the resin portion or rearrangement of the filler due to energization. As described above, when the printout is performed, there is a problem that the volume resistivity of the intermediate transfer member is partially or totally deviated from the range of good volume resistivity with time, and the image quality is deteriorated.

In addition, when the volume resistivity ρv of the intermediate transfer member is high (ρv> 10 ¹⁴ Ωcm), the charge retention property of the intermediate transfer member in the toner image region increases, and an electric field necessary for transfer is appropriately applied to the toner. be able to. On the other hand, since the charge transfer on the surface of the intermediate transfer member in the adjacent non-image portion and the inside thereof is reduced, toner transfer to this region hardly occurs in the primary and secondary transfer. As a result, when the volume resistivity of the intermediate transfer member is high, a toner-formed image with good image quality can be obtained with less toner scattering.
However, in this case, a step of eliminating charges accumulated in the intermediate transfer member after toner transfer is necessary.
JP-A-62-206567 JP-A-6-095521 Japanese Patent Laid-Open No. 5-200904 JP-A-6-228335 Japanese Patent Laid-Open No. 6-149081 Japanese Patent Laid-Open No. 6-149083 Japanese Patent Laid-Open No. 6-149079 JP-A-5-77252 Japanese Patent Laid-Open No. 10-63115 Japanese Patent Laid-Open No. 9-305038 Japanese Patent Laid-Open No. 10-240020 Japanese Patent Laid-Open No. 11-24428 Japanese Patent Laid-Open No. 11-45015 Japanese Unexamined Patent Publication No. Hei 8-248879

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, the first invention maintains durability and reliably prevents the bleed phenomenon, and is effective for deformation over time, change in electrical resistance over time, adhesion of foreign matter to the surface, dirt, etc. Semi-conductivity that can provide stable and good transferability over a long period of time, with excellent prevention, good followability to highly irregular recording media such as embossed paper, and good nip shape formation with the image carrier. The purpose is to provide a belt.
In addition, the second invention is a semiconductive belt that can reliably prevent the bleed phenomenon and prevent the adhesion of foreign matters to the surface, dirt, etc., and can obtain stable and good transferability over a long period of time. The purpose is to provide.
Furthermore, an object of the present invention is to provide an image forming apparatus and an image forming method capable of stably obtaining a high-quality transfer image by including the semiconductive belt.

Means for solving the above problems are as follows.
First, as the first invention,
<1> A semiconductive belt composed of one or more layers, wherein the outermost layer is mainly composed of a thermosetting elastomer composition in which a lubricating filler and a conductive agent are dispersed, and the surface of the outermost layer A semiconductive belt characterized in that the D hardness is 30 to 55, and the ten-point average surface roughness Rz of the outermost layer is 1.5 μm to 9.0 μm.

  <2> The semiconductive belt having the outermost layer and a base material on the inner side thereof, wherein the Young's modulus of the base material is 1000 MPa or more. It is.

  <3> The semiconductive belt according to <1> or <2>, wherein the thermosetting elastomer composition is a polyurethane resin.

  <4> The semiconductive belt according to any one of <1> to <3>, wherein the base material contains a fluorine-based resin composition or a polyimide-based resin composition as a main component. It is.

As the second invention,
<5> A semiconductive belt having an outermost layer and a base material on the inner side thereof, the base material being made of an elastic body, and the outermost layer comprising at least a fluororesin and fluorinated graphite. It is a semiconductive belt characterized by containing.

  <6> The semiconductive belt according to <5>, wherein the content of graphite fluoride contained in the outermost layer is 1.5% by mass or more.

  <7> The semiconductive belt according to <5> or <6>, wherein the outermost layer has a ten-point average surface roughness Rz of 1.5 μm to 9.0 μm.

  <8> The semiconductive belt according to any one of <5> to <7>, wherein a contact angle with respect to water of the outermost layer is 115 ° or more.

  <9> The <5>, wherein the fluororesin is a copolymer that is polymerized using two or more types of monomers, and includes at least tetrafluoroethylene and vinyl ether as the monomers. The semiconductive belt according to any one of to <8>.

The image forming apparatus according to the present invention includes:
<10> An image forming apparatus for recording a toner image formed on an image bearing member on a recording medium, wherein the image forming device is in contact with the transfer conveying belt disposed so as to contact the image bearing member or the image bearing member. An image forming apparatus using the semiconductive belt described in any one of the above items <1> to <9> as the intermediate transfer belt.

  <11> The image forming apparatus according to <10>, wherein the recording is performed on a recording medium having a surface unevenness difference of 40 to 60 μm and a thickness of 100 to 260 μm.

  <12> An image forming apparatus for recording a toner image formed on an image carrier on a recording medium, the plurality of image carriers, the same number of intermediate transfer belts as the image carrier, and one sheet Each of the intermediate transfer belts is in contact with each of the image carriers, and the sheet transfer belt is in contact with all of the intermediate transfer belts. An image forming apparatus using the semiconductive belt according to any one of 1> to <9>.

  <13> The image forming apparatus according to <12>, wherein the recording is performed on a recording medium having a surface unevenness difference of 40 to 60 μm and a thickness of 100 to 260 μm.

  <14> The image forming apparatus according to <12> or <13>, wherein the paper transport belt is a fluororesin belt having a Young's modulus of 1000 MPa or more.

  <15> The image forming apparatus according to any one of <10> to <14>, wherein the transfer conveyance belt or the intermediate transfer belt is disposed in contact with the shape of the image carrier. It is.

Furthermore, the image forming method of the present invention includes:
<16> A toner image forming step for forming a toner image on each of a plurality of image carriers, and the toner image is primary on each intermediate transfer belt disposed so as to be in contact with each image carrier. A primary transfer step for transferring, and a secondary transfer for secondary transfer of a toner image primarily transferred for each intermediate transfer belt onto a recording medium conveyed by a paper conveyance belt arranged so as to be in contact with all the intermediate transfer belts An image forming method including a transfer step, wherein the semiconductive belt according to any one of <1> to <9> is used as the intermediate transfer belt, and a transfer voltage is applied in the secondary transfer step. Is performed after the intermediate transfer belt and the recording medium are in contact with each other.

  <17> The image forming method according to <16>, wherein the image forming method is used for recording on a recording medium having a surface unevenness difference of 40 to 60 μm and a thickness of 100 to 260 μm. .

According to the first aspect of the present invention, durability is maintained and the bleed phenomenon is surely prevented, deformation over time, change in electrical resistance over time, adhesion of foreign matter to the surface, dirt, etc. Stable and good transferability can be obtained over a long period of time by effective prevention of image formation, good followability to recording media with large irregularities such as embossed paper, and good nip shape formation with an image carrier. A semiconductive belt can be provided.
In addition, according to the second invention, the bleed phenomenon can be reliably prevented, and foreign matter can be prevented from adhering to and fouling on the surface. Sex belts can be provided.
Furthermore, according to the present invention, by providing the semiconductive belt, it is possible to provide an image forming apparatus and an image forming method capable of stably obtaining a high-quality transfer image.

The first semiconductive belt in the present invention (refers to the semiconductive belt described in claim 1 and may be simply referred to as “first invention” in this specification) is an electrophotographic type. In an image forming apparatus, a belt used as a transfer conveyance belt or an intermediate transfer belt, which is a semiconductive belt composed of one or more layers, and an outermost layer in which a lubricant filler and a conductive agent are dispersed. The thermosetting elastomer composition is a main component, the surface D hardness of the outermost layer is 30 to 55, and the ten-point average surface roughness Rz of the outermost layer is 1.5 μm to 9.0 μm. And
When the surface D hardness is in the above range, followability can be obtained for special paper with uneven surfaces such as recycled paper, colored paper, and embossed paper, and the ten-point average surface roughness Rz is in the above range. As a result, it is possible to prevent contamination due to accumulation of toner, paper powder, and the like, and discharge unevenness that occurs slightly due to roughness. In addition, by dispersing a lubricant filler that expresses lubricity, toner filming on the belt is less likely to occur, and by dispersing a conductive agent, good conductivity can be obtained, By using a thermosetting elastomer composition that prevents a decrease in resistance over time, an outermost layer that is less deformed over time and has excellent durability can be formed. Also, as a result, stable and good transferability can be obtained over a long period of time as a transfer conveyance belt or an intermediate transfer belt.

Further, the second semiconductive belt in the present invention (refers to the semiconductive belt described in claim 5 and may be simply referred to as “second invention” in this specification) is an electrophotographic. In the image forming apparatus of the type, it is a belt used as a transfer conveyance belt or an intermediate transfer belt, and is a semiconductive belt having an outermost layer and a base material inside thereof, and the base material is made of an elastic body. And the outermost layer contains at least a fluororesin and graphite fluoride.
As a result, it is possible to effectively prevent foreign matter from adhering to the belt surface, dirt, and the like, and as a transfer conveyance belt or an intermediate transfer belt, stable and good transferability can be obtained over a long period of time.

The first semiconductive belt may be composed of one layer or two or more layers, but preferably has a structure composed of two or more layers from the viewpoint of a balance between flexibility and rigidity. The second semiconductive belt is composed of at least two layers having an outermost layer and a base material. Here, as an example of a layer configuration in the first semiconductive belt and the second semiconductive belt (hereinafter, when both are referred to, they may be simply referred to as “the semiconductive belt of the present invention”), A two-layer semiconductive belt is shown in FIG. The semiconductive belt shown in FIG. 1 is an endless belt composed of an outermost layer 1 and a substrate 2.
Hereinafter, the semiconductive belt of the present invention will be described in detail.

<First semiconductive belt>
(Thermosetting elastomer composition)
The first semiconductive belt in the present invention is characterized by comprising a thermosetting elastomer composition. The thermosetting elastomer composition contains at least a thermosetting elastomer, a lubricant filler and a conductive agent are dispersed, and may further contain other additives as necessary. By containing the thermosetting elastomer, it is possible to obtain a semiconductive belt with little deformation over time and excellent durability. When used as an intermediate transfer belt or a transfer conveyance belt, a color register (color Generation of misalignment can be effectively prevented.
As the thermosetting elastomer that can be used for the first semiconductive belt, any resin can be used as long as it has a urethane bond or an ester bond in the repeating unit. From the viewpoint of flexibility, polyurethane resin is more preferable.

(Lubricating filler)
Lubricating fillers are dispersed in the thermosetting elastomer composition.
Although it does not specifically limit as a lubricous filler, For example, polyvinyl fluoride, PVDF, tetrafluoroethylene (TFE) resin, chlorotrifluoroethylene (CTFE) resin, ETFE, CTFE-ethylene copolymer, PFA ( Resin powders of fluorinated compounds such as TFE-perfluoroalkyl vinyl ether copolymer), FEP (TFE-hexafluoropropylene (HFP) copolymer), EPE (TFE-HFP-perfluoroalkyl vinyl ether copolymer) 1 type (s) or 2 or more types are used.

  The lubricating filler is preferably a fine powder having an average particle size of 1 μm or less. When the average particle diameter is larger than 1 μm, the surface of the intermediate transfer belt becomes rough, and transferability is deteriorated. Moreover, the addition amount of a lubricous filler is 3-80 mass parts with respect to 100 mass parts of resin materials, Preferably it is 10-60 mass parts, More preferably, it is 15-40 mass parts. When the addition amount of the lubricating filler is less than 3 parts by mass, the effect of the lubricating filler may not be exhibited, and when 80 parts by mass or more is added, the thermosetting elastomer composition resin is hard. Therefore, there is a case where followability to special paper having uneven surfaces such as recycled paper, colored paper, and embossed paper cannot be obtained. In addition, the inclusion of the lubricating filler can provide an effect that the occurrence of toner filming can be effectively suppressed.

(Conductive agent)
In addition, a conductive agent is dispersed in the thermosetting elastomer composition in order to obtain desired conductivity. A known material can be used as the conductive agent, and it is preferable to add a conductive agent imparting electron conductivity or a conductive agent imparting ionic conductivity, if necessary, in combination of one kind or two or more kinds. It is.

  Examples of the ion conductive conductive agent include sulfonates and ammonia salts, and various surfactants such as cationic, anionic, and nonionic surfactants. Furthermore, there is a method of blending conductive polymers. Examples of the conductive polymer include various (for example, styrene) copolymers with (meth) acrylates that bind a quaternary ammonium base to a carboxyl group, and a quaternary ammonium base. Polymers that bind quaternary ammonium bases, such as a copolymer of maleimide and methacrylate, which binds to styrene, polymers that bind alkali metal salts of sulfonic acids such as sodium polysulfonate, hydrophilic units of at least alkyl oxide in the molecular chain For example, polyethylene oxide, polyethylene glycol-based polyamide copolymer, polyethylene oxy-epichlorohydrin copolymer polyether amide imide, block type polymer having polyether as a main segment, further polyaniline, It can be mentioned Li thiophene, polyacetylene, polypyrrole, polyphenylene vinylene and the like, can be used These conductive Porima undoped state, or in a doped state. The above-described electrical resistance can be stably obtained by using one or two or more of the above-mentioned conductive agent, conductive polymer, or surfactant.

  In addition, it is preferable to use an electroconductive conductive agent from the viewpoint of effectively suppressing variation in resistance to environmental fluctuations. Examples of such electron conductive conductive agents include metals or alloys such as carbon black, graphite, aluminum, nickel, and copper alloys, tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide, or tin oxide-antimony oxide composite. Known metal oxides such as oxides can be used.

  Among these electronic conductive agents, it is preferable to use oxidized carbon black (hereinafter abbreviated as “acidic carbon black”). Acidic carbon black has a functional group such as a carboxyl group on the surface and is compatible with the resin component, so that it can be uniformly dispersed. For this reason, it is possible to reduce the variation in resistance value as described above. In addition, the pH of acidic carbon black is 5 or less. By setting the pH of the acidic carbon black to 5 or less, when a voltage is repeatedly applied to the belt base material, an excessive current flows in part, thereby further oxidizing the surface of the acidic carbon black. Further, it is possible to prevent the problem that the acidic carbon black characteristics are greatly changed and the semiconductive resistance is changed.

  By using acidic carbon black having a pH of 5 or less as the electron conductive conductive agent, an excessive current flows in part or it is difficult to be affected by oxidation due to repeated voltage application. Furthermore, the effect of the oxygen-containing functional group attached to the surface of the acidic carbon black has high dispersibility to the base material, and resistance variation can be reduced. Disappear. As a result, resistance change due to energization is prevented, uniformity of electrical resistance is improved, electric field dependency is small, resistance change due to environment is also small, and more uniform chargeability and transferability can be obtained. is there.

  For this reason, it is possible to prevent leakage discharge such as pinhole leak, which is thought to occur due to electric field concentration and dielectric breakdown due to the occurrence of large aggregates of carbon black as in the past, and also to prevent toner sticking. be able to. Further, charging unevenness due to resistance change or resistance variation, image quality defects due to leakage discharge, and fluctuations in image density due to environmental fluctuations are reduced, and high-quality images can be obtained over a long period of time. In addition, acidic carbon black does not require a coupling process for improving dispersibility, addition of insulating particles, metal oxides, and the like, and the manufacturing process is simplified.

  The pH of the acidic carbon black is not particularly limited as long as it is 5 or less as described above, but is preferably 4.5 or less, more preferably 4.0 or less. The pH of the acidic carbon black is defined as follows (details conform to JIS K6221-1982). The “pH” of acidic carbon black refers to the pH (logarithmic value of hydrogen ion concentration) measured for a muddy substance obtained by boiling carbon black with water and removing the supernatant after cooling. It is related to the amount of oxygen-containing functional groups on the carbon black surface (functional groups such as carboxylic acid, hydroxy acid, lactone, and quinoid), and it is thought that the lower the pH, the more acidic surface functional groups (the Carbon Black Association) Edited / published "Carbon Black Handbook" (1995)).

In addition, there is a volatile matter as a physical property value representing the amount of the oxygen-containing functional group on the surface of carbon black. This volatile content is expressed as a percentage of the weight loss when carbon black is held in an atmosphere of 950 ± 25 ° C. for 7 minutes.

The oxidized carbon black preferably has a volatile component content of 1 to 25% by mass, more preferably 3 to 20%, and even more preferably 3.5 to 15% by mass. . When the content of the volatile component is less than 1% by mass, the effect of the oxygen-containing functional group attached to the outside is lost, and the dispersibility in the binder resin may be reduced. On the other hand, when the content of the volatile component is higher than 25%, it may be decomposed when dispersed in the resin composition, or the amount of water adsorbed on the outer oxygen-containing functional group is increased. The appearance of the outermost layer or the substrate may be deteriorated.
On the other hand, the dispersion | distribution in the said resin composition can be made more favorable because content of a volatile component shall be 1-25 mass%.

  Acidic carbon black can be produced by a contact method. Examples of the contact method include a channel method and a gas black method. Moreover, acidic carbon black can also be manufactured by the furnace black method which uses gas or oil as a raw material. If necessary, after these treatments, a liquid phase oxidation treatment with nitric acid or the like may be performed. In the furnace method, only carbon black having a high pH and a low volatile content is usually produced, but the pH can be adjusted by performing the above-described liquid phase oxidation treatment. For this reason, carbon black obtained by furnace method production and adjusted to have a pH of 5 or less by post-treatment can also be suitably used in the present invention.

  Specific examples of the oxidation-treated carbon black include “Printex 150T” (pH 4.5, volatile content 10.0% by mass) and “Printex 140U” (pH 4.5, volatile content 5%) manufactured by Degussa. “Special Black 350” (pH 3.5, volatile matter 2.2 mass%), “Special Black 100” (pH 3.3, volatile matter 2.2 mass%), “Special Black 250” (pH 3. 1, volatile content 2.0% by mass), "Special Black 5" (pH 3.0, volatile content 15.0% by mass), "Special Black 4" (pH 3.0, volatile content 14.0% by mass) “Special Black 4A” (pH 3.0, volatile content 14.0% by mass), “Special Black 550” (pH 2.8, volatile content 2.5% by mass), “Special Black 6” (pH) , Volatile matter 18.0 mass%), "Color Black FW200" (pH 2.5, volatile content 20.0 mass%), "Color Black FW2" (pH 2.5, volatile content 16.5 mass%) ), “Color Black FW2V” (pH 2.5, volatile content 16.5 mass%), “MONARCH 1000” (pH 2.5, volatile content 9.5 mass%) manufactured by Cabot Corporation, “MONARCH 1300” (pH 2) manufactured by Cabot Corporation , Volatile content of 9.5% by mass), “MONARCH1400” manufactured by Cabot (pH 2.5, volatile content of 9.0% by mass), “MOGUL-L” (pH 2.5, volatile content of 5.0% by mass) ), "REGAL400R" (pH 4.0, volatile content 3.5 mass%) and the like.

  Acidic carbon black may be blended alone in the resin composition constituting the belt base material, but any two or more kinds of acidic carbon black may be blended to obtain mechanical strength, hardness, elastic modulus, etc. It can also be formulated to meet the requirements of the entire system. The compounding amount in the resin composition does not enter a suitable resistance region unless the concentration is higher than that of ordinary conductive carbon black, but is generally 5 to 40 parts by mass (the number of parts by mass with respect to 100 parts by mass of the resin composition). preferable. If the amount is less than 5 parts by mass, the resistance is too high and the desired resistance cannot be obtained. On the other hand, when the amount exceeds 40 parts by mass, the resistance is too low and image quality defects such as white spots may occur.

(Surface D hardness of outermost layer)
The surface D hardness of the outermost layer in the first semiconductive belt is D hardness according to JIS K7215 (1986), and is essentially 30 to 55, preferably 30 to 53,
35-52 is particularly preferred. Because the D hardness of the outermost layer is 30 to 55, it has the ability to follow special paper with uneven surfaces such as colored paper and embossed paper, which has been difficult to print with high image quality. As a result, the transferability of the toner can be improved.
When the D hardness of the outermost layer exceeds 55, the belt is too hard to follow the special paper with irregularities on the surface such as colored paper or embossed paper, resulting in poor toner transferability. There is. In addition, when used in close contact with the surface of the image carrier, image quality defects such as poor followability to the surface of the image carrier, poor toner transferability, and line images being lost (holocharacter). May occur. When the surface D hardness is less than 30, the dimensional change becomes large, and there is a concern about long-term use, and the outermost layer is easily damaged by a metal cleaning member, paper dust (calcium carbonate contained in paper), or the like. Problems may occur.
The D hardness of the outermost layer was measured in accordance with JIS K7215 (1986) by laminating sheet-like outermost layer materials to a thickness of 6 mm.

(Ten point average surface roughness Rz)
The ten-point average surface roughness Rz of the outermost layer in the first semiconductive belt is essential to be 1.5 to 9.0 μm, more preferably 3 to 8 μm, and 4 to 7 μm. It is particularly preferred. If the ten-point average surface roughness Rz is less than 1.5 μm, there is a concern that the ten-point average surface roughness Rz is in close contact with the contact member. If the ten-point average surface roughness Rz is greater than 9.0 μm, toner and Paper powder or the like tends to accumulate, and minute discharge unevenness may occur due to unevenness, so that uniform transferability and image quality may deteriorate with time. The ten-point average surface roughness Rz is the surface roughness specified in JIS B0601 (1994).
The 10-point average surface roughness Rz can be measured by using a surface roughness measuring instrument or the like. In the present invention, however, a contact-type surface roughness measuring device (in a 23 ° C./55RH% environment) Surfcom 570A, manufactured by Tokyo Seimitsu Co., Ltd.) was used. When measuring the surface of the semiconductive belt, the measurement distance was 2.5 mm, and the tip of the contact needle was diamond (5 μmR, 90 ° cone). The value was determined as the ten-point average surface roughness Rz of the semiconductive belt.
Here, the ten-point average surface roughness Rz can be controlled by the shape and addition amount of the lubricating filler and the conductive agent.

(Base material)
As described above, the first semiconductive belt preferably has a base material inside the outermost layer.
The base material constituting the first semiconductive belt preferably has a Young's modulus of 1000 MPa or more, more preferably 1500 MPa or more, and particularly preferably 2000 MPa or more. When the pressure is 1000 MPa or more, a balance between flexibility and rigidity that cannot be obtained with a single-layer configuration can be obtained more effectively, and the amount of displacement of the belt due to disturbance (load fluctuation) during driving of the belt is reduced. The belt deformation with respect to the stress of time becomes small, and good image quality can be obtained stably.
The Young's modulus was obtained by performing a tensile test in accordance with JIS K6911 (1995), drawing a tangent line to the curve of the initial strain region of the obtained stress / strain curve, and determining the slope.

  As the constituent resin used for the substrate, those satisfying the above Young's modulus range are preferable. For example, polyimide resin, polyamideimide resin, fluorine-based resin, vinyl chloride vinyl acetate copolymer, polycarbonate resin, polyethylene terephthalate resin, chloride Examples thereof include vinyl resins, ABS resins, polymethyl methacrylate resins, polybutylene terephthalate resins, and the like. These may be used alone or in combination of two or more. Among these, a polyimide resin and a fluorine resin are preferably used because they are excellent in both strength and bending fatigue.

  Examples of the polyimide resin include those obtained by reacting an aromatic tetracarboxylic acid component and an aromatic diamine component in an organic polar solvent.

  As aromatic tetracarboxylic acid components, pyromellitic acid, naphthalene-1,4,5,8-tetracarboxylic acid, naphthalene-2,3,6,7-tetracarboxylic acid, 2,3,5,6-biphenyl Tetracarboxylic acid, 2,2 ′, 3,3′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-biphenyltetracarboxylic acid, 3,3 ′, 4,4′-diphenylethertetracarboxylic acid Acid, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid, 3,3 ′, 4,4′-diphenylsulfonetetracarboxylic acid, 3,3 ′, 4,4′-azobenzenetetracarboxylic acid bis (2 , 3-dicarboxyphenyl) methane, bis (3,4-dicarboxyphenyl) methane, β, β-bis (3,4-dicarboxyphenyl) propane, β, β-bis (3,4-dicarbo) Shifeniru) has hexafluoropropane, etc., it may be a mixture of these tetracarboxylic acids.

  The aromatic diamine component is not particularly limited, and m-phenyldiamine, p-phenyldiamine, 2,4-diaminotoluene, 2,6-diaminotoluene, 2,4-diaminochlorobenzene, m-xylylenediamine P-xylylenediamine, 1,4-diaminonaphthalene, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 2,4′-diaminonaphthalene biphenyl, benzidine, 3,3-dimethylbenzidine, 3,3 ′ -Dimethoxybenzidine, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether (oxy-p, p'-dianiline; ODA), 4,4'-diaminodiphenyl sulfide, 3,3 '-Diaminobenzophenone, 4,4'-diaminophenylsulfone, 4,4'-diamino Zobenzen, 4,4'-diaminodiphenylmethane, beta, beta-bis (4-amine phenyl) propane.

  Examples of the organic polar solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphortriamide and the like. These organic polar solvents can be mixed with phenols such as cresol, phenol and xylenol, and hydrocarbons such as hexane, benzene and toluene, if necessary. Solvents are also used alone or as a mixture of two or more.

  On the other hand, examples of the fluorine-based resin include vinylidene fluoride-tetrafluoroethylene copolymer [Poly (VdF-TFE)], ethylene-tetrafluoroethylene copolymer (ETFE), and polychlorotrifluoroethylene (PCTFE). ), Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), and the like. Among these, Poly (VdF-TFE) is preferably used.

(Volume resistivity)
The volume resistivity of the outermost layer in the first semiconductive belt (in the case of a semiconductive belt made of a single layer, the single layer) is preferably 1 × 10 ⁸ Ωcm or more. Transfer at the time of transferring the toner image on the image carrier onto the recording medium on the transfer conveyance belt (semiconductive belt) or the intermediate transfer belt (semiconductive belt) by being 1 × 10 ⁸ Ωcm or more. In the electric field, the surface of the semiconductive belt is charged and the charge holding power increases, so that the toner is scattered around the image by the electrostatic repulsion between the toners and the fringe electric field near the image edge. (Blurring) problems are less likely to occur.

In the case where the image forming apparatus using the semiconductive belt has a mode in which a charge eliminating means is provided to the semiconductive belt by applying an AC voltage or the like, the volume resistivity of the outermost layer is 1 × 10 ¹³ Ωcm or more. It is more preferable that it is 2 × 10 ¹³ Ωcm or more. When the volume resistivity of the outermost layer is higher than 1 × 10 ¹³ Ωcm, the blur problem can be more effectively prevented when applied to an electrophotographic image forming apparatus provided with a charge eliminating means.

On the other hand, in the case where the charge eliminating means is not provided, the volume resistivity of the outermost layer is more preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, and 1 × 10 ⁹ to 1 × 10 ¹² Ωcm. It is particularly preferred. If it is 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, the problem of blurring is less likely to occur as described above, and at the same time, the charged charge after transfer is appropriately attenuated (particularly when applied to an intermediate transfer member). Therefore, it is possible to continuously form an image without providing a charge eliminating unit.

In addition, the volume resistivity of the substrate is preferably 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, and more preferably 1 × 10 ⁹ to 1 × 10 ¹² Ωcm, regardless of the presence or absence of the charge eliminating means. If it is 1 × 10 ⁸ to 1 × 10 ¹³ Ωcm, the problem of the blur is less likely to occur.

Here, the volume resistivity can be measured according to JIS K6911 (1995) using a circular electrode (for example, HR probe of Hiresta IP manufactured by Dia Instruments Co., Ltd.). A method for measuring the volume resistivity will be described with reference to the drawings.
FIG. 2 is a schematic plan view (a) and a schematic cross-sectional view (b) showing an example of a circular electrode. The circular electrode shown in FIG. 2 includes a first voltage application electrode A ′ and a second voltage application electrode B ′. The first voltage application electrode A ′ has a cylindrical electrode part C ′ and a cylindrical shape having an inner diameter larger than the outer diameter of the cylindrical electrode part C ′ and surrounding the cylindrical electrode part C ′ at a constant interval. Ring-shaped electrode portion D ′. A semiconductive belt T ′ is sandwiched between the cylindrical electrode portion C ′ and the ring electrode portion D ′ and the second voltage application electrode B ′ in the first voltage application electrode A ′, and the first voltage application electrode A ′. The current I (A) flowing when the voltage V (V) is applied between the cylindrical electrode portion C ′ and the second voltage applying electrode B ′ in FIG. The resistivity ρv (Ωcm) can be calculated. Here, in the following formula, t represents the thickness of the semiconductive belt T ′.
Formula: ρv = 19.6 × (V / I) × t

(Semiconductive belt thickness)
When the thickness of the first semiconductive belt is increased, the deformation amount of the outer surface of the belt at a belt bending portion such as a drive system roll is increased, and a good image quality may not be obtained. Further, the deformation amount between the outer side and the inner side of the belt increases, and there may be a problem that the belt breaks due to local repeated stress.
The thickness of the first semiconductive belt is preferably 0.05 to 0.5 mm, more preferably 0.1 to 0.4 mm, and more preferably 0.15 to 0 in terms of the total thickness of all belt layers. More preferably, it is 3 mm. When the thickness is 0.05 mm or more, problems such as a change in belt circumference due to belt tension can be effectively prevented, and when the belt thickness is 0.5 mm or less, Since deformation of the belt surface can be reduced, problems such as cracks on the surface can be prevented.
Further, the thickness of the outermost layer is preferably 10 to 90% of the total thickness of the belt, more preferably 30 to 70%, and if it is within the above range, the resin composition of the base material is affected. Instead, the pressing force concentrated on the toner on the semiconductive belt is dispersed. For this reason, the toner does not aggregate, and the followability to special paper with irregularities on the surface of colored paper or embossing is improved, so the transferability of special paper toner with irregularities on the surface of colored paper or embossing etc. Can be improved.

<Second semiconductive belt>
(Graphite fluoride)
The second semiconductive belt according to the present invention includes a fluororesin having a low surface energy and graphite fluoride in the outermost layer, so that the surface energy can be reduced. It is difficult for foreign matter and dirt to adhere to the surface of the conductive belt.
In addition, since it contains delaminated graphite fluoride, the coefficient of dynamic friction between the semiconductive belt and the image carrier can be reduced, and a synergistic effect with a reduction in the surface energy of the surface of the semiconductive belt. Thus, contamination of the surface of the semiconductive belt can be effectively prevented.

Examples of the graphite fluoride include (C ₂ F) n-type Cefbon DM (manufactured by Central Glass), (CF) n-type Cefbon CMA, Cefbon CMF (manufactured by Central Glass), and fluorocarbon # 2065, # 1030, # 1000 (manufactured by Asahi Glass Co., Ltd.), CF-100 (manufactured by Nippon Carbon Co., Ltd.), and fluorocarbons # 2028, # 2010 (manufactured by Asahi Glass Co., Ltd.) having a different fluorination rate with (CF) n type, Furthermore, the above-mentioned carbon fluoride is treated with a base such as an amine to remove fluorine on the surface, and the like, (CF) n type Cefbon CMA, Cefbon CMF, fluorocarbon # 2065, # 1030, # 1000. CF-100 is more preferable.

As content of the said graphite fluoride, it is preferable that it is 1.5 mass% or more, and it is preferable that an upper limit is 50 mass% or less. Furthermore, it is more preferable that it is in the range of 2% by mass to 23% by mass.
When the content of graphite fluoride is 1.5% by mass or more, a hard substance such as a toner external additive is embedded so as to pierce the surface of the semiconductive belt material, and is triggered by a trigger. Fixing can be effectively prevented, and deterioration of uniform transferability and image quality over time can be prevented. On the other hand, when it is 50% by mass or less, the flexibility of the outermost layer is maintained, the problem of not following the elastic body of the base material is solved, and the fluorinated graphite itself contaminates the surface of the semiconductive belt. Can be prevented.
The content of fluorine contained in the graphite fluoride is not particularly limited, but is preferably 20% by mass or more, and more preferably 40% by mass or more.

(Fluorine resin)
Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polyvinylidene fluoride (PVDF), Tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), polyvinyl fluoride (PVF), fluoroolefin-vinyl ether copolymer, fluorine And resins such as vinylidene fluoride-tetrafluoroethylene copolymer and vinylidene fluoride-hexafluoropropylene copolymer. You may use these individually or in combination of 2 or more types.

  Among these fluororesins, it is a copolymer that is polymerized using at least two types of monomers, and it is a simple thin film that contains at least tetrafluoroethylene and vinyl ether as the monomers. Since the liquid phase coating method which is a formation method can be used, it is preferable. For example, as a tetrafluoroethylene-alkyl vinyl ether copolymer, Zeffle GK-500 (manufactured by Daikin Industries) or as a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, Cytop (manufactured by Asahi Glass Co., Ltd.) is preferably used. It is done.

  Although content of the fluororesin contained in an outermost layer is not specifically limited, It is preferable to exist in the range of 20 mass%-95 mass%, and it is more preferable to exist in the range of 40 mass%-95 mass%. In the outermost layer, other resin components other than the fluororesin may also be included. When the content of the fluororesin contained in the outermost layer is 20% by mass or more, the surface energy of the surface of the semiconductive belt can be kept small, and contamination such as toner adhesion can be effectively prevented. In addition, as described above, the upper limit is preferably 95% by mass or less from the viewpoint of including a necessary amount of other necessary components other than the fluororesin in the outermost layer.

(Other additives)
As the material constituting the outermost layer, in addition to the fluororesin and fluorinated graphite as described above, a resin material other than the fluororesin and, if necessary, additives such as a known conductive agent and a crosslinking agent are used. Can be added. Examples of the resin material other than the fluororesin include polyurethane, polyamide, and polyester.

Further, as the conductive agent, a known conductive material such as carbon black, conductive metal oxide such as tin oxide, etc. as mentioned in the first semiconductive belt can be used.
Examples of the crosslinking agent include isocyanates, melamines, methylated, ethylated, epoxy resins, bisphenol type epoxy resins, epoxy-based polymers, and the like, and blends thereof.
Moreover, other additives other than these can also be used as needed.

(Contact angle of water of outermost layer)
The contact angle of water on the outermost layer in the second semiconductive belt (hereinafter sometimes abbreviated as “contact angle”) is preferably 115 ° or more. When the contact angle with respect to water of the outermost layer is 115 ° or more, contamination such as toner sticking to the surface does not occur, and it is possible to effectively prevent uniform transferability and deterioration of image quality over time. . Furthermore, the contact angle is preferably 120 ° or more, and more preferably 125 ° or more.
The contact angle can be measured using a goniometer or the like. In the present invention, the contact angle after dropping water on the surface of the belt and leaving it for 10 seconds in an environment of 23 ° C. and 55% RH. Was measured using a contact angle measuring device CA-X roll type (manufactured by Kyowa Interface Science Co., Ltd.). In addition, the average value when the measurement was repeated three times at different locations was obtained as the contact angle of the semiconductive belt.
Here, the contact angle can be controlled by the type and amount of the lubricating filler.

(Base material)
The second semiconductive belt in the present invention must have a base material made of an elastic body inside the outermost layer, and a conductive elastic body is preferably used for the base material. By adopting such a configuration, the semiconductive belt is kept within a desired resistance value and hardness so that the semiconductive belt can be pressed onto the surface of the image carrier with an appropriate nip width or nip pressure and transferred uniformly. Can do.

This elastic body is formed by dispersing conductive particles in a rubber material.
Examples of the rubber material include isoprene rubber, chloroprene rubber, epichlorohydrin rubber, butyl rubber, urethane rubber, silicone rubber, fluorine rubber, SBR, NBR, EPDM, acrylonitrile-butadiene-styrene rubber, and blended rubbers thereof. Of these, isoprene rubber, silicone rubber, and EPDM are preferably used.

Moreover, as above-mentioned, in order to obtain desired electroconductivity, electroconductive particle can be added. As the conductive particles, known materials can be used, but it is preferable to use an electron conductive conductive agent in terms of effectively suppressing variation in resistance to environmental fluctuations.
Examples of such electron conductive conductive agents include metals or alloys such as carbon black, graphite, aluminum, nickel, and copper alloys, tin oxide, zinc oxide, kalim titanate, tin oxide-indium oxide, or tin oxide-antimony oxide composite. Known metal oxides such as oxides can be used.

  Carbon black suitable as an electron conductive conductive agent has a property of being bonded in a chain form in a rubber composition (elastic body) to which the carbon black is added, and the resistance value of the rubber composition according to the length of the chain bond. Will be different. If this chain bond is long, the conductivity of the conductive elastic body is improved and its resistance value is lowered. On the other hand, if the chain bond is short, the conductivity of the conductive elastic body is lowered and its resistance value is increased. That is, when carbon black that forms a long chain bond is added, the amount of carbon black added to develop a desired resistance value can be reduced compared to carbon black that forms a short chain bond, Since the resistance value largely fluctuates due to the change of the addition amount, the above-described variation in the resistance value in the conductive elastic body cannot be reduced.

In addition, as the electron conductive conductive agent, it is also preferable to use two or more types of carbon blacks having different characteristics such as surface characteristics.
The length of the chain bond of the carbon black described above depends on the particle size and surface activity of the individual particles of the carbon black. (Dibutyl phthalate) has oil absorption. This DBP oil absorption is expressed by whether the amount (ml) of DBP absorbed by 100 g of carbon black is large or small. The higher the DBP oil absorbency, that is, the greater the amount of oil absorbed, the longer the carbon chain.

If only the carbon black having a high DBP oil-absorbing property is added to the rubber composition to adjust the resistance value of the elastic body, the resistance value greatly changes even if the addition amount is slightly increased or decreased. Therefore, a predetermined resistance value cannot be imparted to the elastic body unless the addition amount and dispersion state of carbon black are strictly defined. On the other hand, if only the carbon black having a low DBP oil absorbency is added and the resistance value of the elastic body is adjusted, the carbon black is substantially less in the rubber composition than the case where only the carbon black having a high DBP oil absorbency is added. Since it disperses uniformly, the rate of change in resistance value with an increase or decrease in the amount added decreases. However, in order to give a predetermined resistance value to the elastic body, it is necessary to add a larger amount of carbon black than when adding only carbon black having high DBP oil absorption. As a result, since the blending ratio of carbon black in the rubber composition is increased, when the rubber composition is kneaded with a Banbury mixer, a kneader or the like, the viscosity becomes high and processing becomes difficult. Moreover, the problem that the obtained elastic body becomes high hardness may generate | occur | produce.
Therefore, it is preferable to use two or more types of carbon black having high DBP oil absorbability and carbon black having low DBP oil absorbency, which have different DBP oil absorbability.

  The two or more types of carbon blacks only need to have a difference in DBP oil absorption, but if this difference is too small, the same result as that obtained when one type of carbon black is added will be produced. Accordingly, carbon black having a certain difference in DBP oil absorption is preferable, and at least one carbon black having a different DBP oil absorption is a carbon black having a DBP oil absorption of 250 ml / 100 g or more (DBP oil absorption). The carbon black having a high oil absorption is preferably 150 ml / 100 g or less (carbon black having a low DBP oil absorption).

The DBP oil absorption of carbon black having a high DBP oil absorption is 280 ml / 100 g or more, and the DBP oil absorption of carbon black having a low DBP oil absorption is more preferably 110 ml / 100 g or less.
In the present invention, as the two or more types of carbon blacks having different DBP oil absorption properties, at least the carbon black having a high DBP oil absorption property and the carbon black having a low DBP oil absorption property may be used. Carbon blacks with different amounts may further be included.

  Specifically, as the carbon black having high DBP oil absorption, for example, HS-500 (manufactured by Asahi Carbon Co., Ltd.) having a DBP oil absorption of 447 ml / 100 g, Ketjen black (Lion Exo (product of Asahi Carbon Co., Ltd.)) And carbon black such as Vulcan XC-72 (manufactured by Cabot Corporation) having a DBP oil absorption amount of 288 ml / 100 g and DBP oil absorption amount of 265 ml / 100 g. Moreover, as carbon black with low DBP oil absorption, Asahi Thermal FT (Asahi Carbon Co., Ltd.) having a DBP oil absorption of 28 ml / 100 g, Asahi Thermal MT (Asahi Carbon Co., Ltd.) having a DBP oil absorption of 35 ml / 100 g are used. ) And the like.

  In general, carbon black having a higher DBP oil absorption tends to have a smaller primary particle size, and the carbon black having a higher DBP oil absorption has a primary particle size in the range of 5 to 50 nm. It is preferable to use carbon black having a low primary property with a primary particle size in the range of 20 to 100 nm.

As a specific example, when adjusting the resistance value of a conductive elastic body using a mixture of carbon black having high DBP oil absorbency (such as acetylene black) and carbon black having low DBP oil absorbency (such as thermal black), the mixing The ratio is preferably in the range of 1: 1 to 1: 8 by mass ratio (mass of carbon black with high DBP oil absorbency (A): mass of carbon black with low DBP oil absorbency (B)), and 1: 2 More preferably, it is in the range of ˜1: 6, and particularly preferably in the range of 1: 2 to 1: 5.
In the above mass ratio, when B is 1 or more, the variation in resistance value is small, and the change in resistance value of the elastic body due to the increase or decrease in the amount of addition can be reduced. On the other hand, when the B is 8 or less, as described above, the rubber composition at the time of kneading can be reduced in viscosity, the molding process of the elastic body is facilitated, and the hardness of the elastic body is also appropriate. Range.

  Thus, the rapid change of the resistance value of an elastic body can be suppressed by adjusting the mixing ratio of carbon black having different DBP oil absorbency and the blending amount with respect to the rubber material. At the same time, it is possible to form an elastic body having a small variation in resistance value with a small amount of addition compared to the case of carbon black alone having a low DBP oil absorption.

  The compounding amount of the carbon black into the rubber composition is added so as to obtain a desired volume resistivity, and is preferably about 5 to 40 parts by mass (amount relative to 100 parts by mass of the rubber composition). When the amount is 5 parts by mass or more, the resistance can be lowered and a desired resistance can be obtained. On the other hand, when the content is 40 parts by mass or less, the resistance is not excessively increased, and image quality defects such as white spots can be effectively prevented.

(Other additives)
In addition to the carbon black, a cross-linking agent, a filler, and the like are appropriately blended in the elastic body constituting the base material used for the second semiconductive belt as necessary.
The crosslinking agent is not particularly limited, and conventionally known ones such as thiourea, triazine, sulfur and the like can be mentioned. Examples of the filler include insulating fillers such as silica, talc, clay and titanium oxide, and these may be used alone or in combination.

  The elastic body can be produced by mixing the components described above with a mixer such as a tumbler, V-type blender, Nauta mixer, Banbury mixer, kneading roller, or extruder. The mixing method of each component and the order of mixing are not particularly limited. As a general method, all components are mixed in advance with a tumbler, V blender, etc., and uniformly melt-mixed by an extruder. Depending on the shape of the components, two or more types of molten mixtures in these components are used. Alternatively, a method of melt-mixing the remaining components can be used.

(10-point average surface roughness Rz, etc.)
In the second semiconductive belt, the ten-point average surface roughness Rz is preferably 1.5 to 9.0 μm, more preferably 3 to 8 μm, and particularly preferably 4 to 7 μm. In addition, the details of the ten-point average surface roughness Rz are the same as described for the first semiconductive belt.
The thickness of the outermost layer in the second semiconductive belt is preferably in the range of 0.5 μm to 100 μm. When the thickness of the outermost layer is 0.5 μm or more, the anti-contamination effect on the surface of the semiconductive belt can be satisfactorily exhibited. On the other hand, when the thickness is 100 μm or less, the surface hardness of the semiconductive belt is good. In such a range that sufficient adhesion to the surface of the image carrier can be obtained. In addition, details regarding the thickness of the entire belt and the like are the same as in the description of the first semiconductive belt.
Furthermore, the volume resistivity of the second semiconductive belt is the same as that described for the first semiconductive belt.

<Manufacture of semiconductive belt>
Since the shape of the semiconductive belt (the first semiconductive belt and the second semiconductive belt) of the present invention described above is an endless shape, an adhesive method using an adhesive at the film end or the like is appropriately selected. It can be formed by a simple connection method or can be a seamless belt. The seamless belt has an advantage that an arbitrary portion can be set as the rotation start position without any change in the thickness of the joint portion, and a control mechanism for the rotation start position can be omitted.

The production method will be described by taking a belt having a two-layer structure consisting of a base material and an outermost layer as an example. The base material and the outermost layer are formed by forming the material of each layer into a sheet shape by an extrusion molding method, and then forming a metal. It is possible to form a two-layer belt by laminating the core and heat-treating it, or forming the base material in a belt shape, laminating it on the metal core, and forming the outermost layer thereon. It can also be formed. Also, a two-layer belt can be formed by simultaneous molding while laminating the outermost layer and the base material.
Further, in addition to the outermost layer and the base material, it is possible to further increase the number of layers as long as the effects of the present invention are not impaired.

<Image forming apparatus>
Next, the above-described semiconductive belt of the present invention is used as a transfer conveyance belt disposed so as to be in contact with the image carrier or an intermediate transfer belt disposed so as to be in contact with the image carrier. The forming apparatus will be described.
The image forming apparatus of the present invention is particularly limited as long as it has a transfer conveyance belt disposed so as to contact the image carrier or an intermediate transfer belt disposed so as to contact the image carrier. It is not a thing. For example, a normal monocolor image forming apparatus that contains only a single color toner in the developing device, or a color image in which a toner image carried on an image carrier such as a photosensitive drum is repeatedly subjected to primary transfer sequentially to an intermediate transfer member Any of a forming apparatus, a tandem type color image forming apparatus in which a plurality of image carriers having developing units for respective colors are arranged in series on an intermediate transfer member may be used.
In the image forming apparatus of the present invention, the semiconductive belt of the present invention having excellent transfer performance is used as a transfer conveyance belt or an intermediate transfer belt. Therefore, the surface unevenness difference is 40 to 60 μm and the thickness is 100 to 260 μm. The followability to a recording medium (for example, a recording medium having large irregularities such as embossed paper) becomes good, and a high-quality transfer image can be obtained.

First, an example of a main part of an image forming apparatus using the semiconductive belt of the present invention as a transfer / conveying belt is shown in FIG. The image forming apparatus has an image carrier 6a and a transfer conveyance belt (semiconductive belt) 5a opposite to the image carrier 6a. After holding the recording medium 7a on the transfer conveyance belt 5a, the toner on the image carrier 6a. The image is transferred to the recording medium 7a on the transfer conveyance belt 5a by the transfer device 8a.
FIG. 4 shows an example of a main part of an image forming apparatus using the semiconductive belt of the present invention as an intermediate transfer belt. The image forming apparatus includes an image carrier 6b and an intermediate transfer belt (semiconductive belt) 5b facing the image carrier 6b. The toner image on the image carrier 6b is primarily transferred to the intermediate transfer belt 5b by the primary transfer device 8b. After the transfer, the toner image on the intermediate transfer belt 5b is secondarily transferred to the recording medium 7b by the secondary transfer device 4b.

As shown in FIGS. 3 and 4, the semiconductive belt (transfer conveyance belt 5a or intermediate transfer belt 5b) is stretched around a plurality of stretching rolls 9a or 9b, and a drum-shaped image carrier 6a or 6b. The aspect arrange | positioned in contact along the shape of is preferable.
By causing the semiconductive belt 5a or 5b to follow the shape of the image carrier 6a or 6b as much as possible, discharge due to useless gaps before and after the nip area during transfer is eliminated and toner image scattering (blur) is prevented. be able to.

  Further, in the image forming apparatus shown in FIGS. 3 and 4, one of the image carrier 6a or 6b and the semiconductive belt (transfer conveyance belt 5a or intermediate transfer belt 5b) is used as a drive source, and the other is driven and rotated. An embodiment is preferable. By adopting such a drive configuration, one of the drive mechanisms can be omitted, and accordingly, the drive cost can be reduced, and from the drive interference between the semiconductive belt 5a or 5b and the image carrier 6a or 6b. Variation factors such as variation in the thickness of the semiconductive belt 5a or 5b and feed variation in the process direction can be excluded.

Here, a specific example of the image forming apparatus of the present invention having the above-described embodiment will be shown. The image forming apparatus of the present invention is not limited to these.
The image forming apparatus shown in FIG. 5 has a photosensitive drum (image carrier) 10 and a shape of the photosensitive drum 10 in a certain area on the photosensitive drum 10 in order to transfer a toner image from the photosensitive drum 10. And an intermediate transfer belt 20 in contact with each other.
The photosensitive drum 10 is provided with a photosensitive layer whose resistance value is lowered by light irradiation. Around the photosensitive drum 10, a charging device 11 for charging the photosensitive drum 10 and a charged photosensitive drum are provided. An exposure device 12 that writes an electrostatic latent image of each color component (in this example, yellow, magenta, cyan, and black) on the body drum 10, and each color component latent image formed on the photosensitive drum 10 is used as each color component toner. A rotary type developing device 13 for visualizing the image, the intermediate transfer belt 20, and a cleaning device 17 for cleaning residual toner on the photosensitive drum 10 are provided.

Here, as the charging device 11, for example, a charging roll is used, but a charging device such as a corotron may be used.
The exposure device 12 may be any device that can write an image on the photosensitive drum 10 with light. In this example, for example, a print head using LEDs is used, but the present invention is not limited to this. The print head used may be selected as appropriate, such as a scanner that scans a laser beam with a polygon mirror.
Further, the rotary type developing device 13 is rotatably mounted with developing devices 13a to 13d containing respective color component toners. For example, the respective color component toners are attached to a portion of the photosensitive drum 10 where the potential is lowered by exposure. The toner to be used is not particularly limited in shape and particle size, and any toner may be used as long as it is accurately placed on the electrostatic latent image on the photosensitive drum 10.
Furthermore, the cleaning device 17 may be appropriately selected as long as it cleans the residual toner on the photosensitive drum 10 and employs a blade cleaning method. However, there may be a mode in which the cleaning device 17 is not used when toner having a high transfer rate is used.

Further, the intermediate transfer belt 20 is stretched around four stretching rolls 21 to 24 and is predetermined along the surface of the photosensitive drum 10 positioned between the rotary developing device 13 and the cleaning device 17. Only the contact region is closely arranged.
Here, the intermediate transfer belt 20 and the photosensitive drum 10 may be driven by separate drive systems, but in this embodiment, the intermediate transfer belt 20 is an elastic belt as described later, and the photosensitive member. The intermediate transfer belt 20 may be driven and rotated by using the photosensitive drum 10 as a drive source, for example, because it is disposed in contact with the circumferential surface of the drum 10.

A primary transfer roll 25 as a primary transfer device is disposed in contact with a part of the contact area where the intermediate transfer belt 20 is in close contact with the photosensitive drum 10 from the back side of the intermediate transfer belt 20, and a predetermined primary transfer bias is applied. Applied.
Furthermore, a secondary transfer roll 30 as a secondary transfer device is disposed opposite to the tension roll 22 of the intermediate transfer belt 20 with the tension roll 22 as a backup roll, for example, the secondary transfer roll 30. A predetermined secondary transfer bias is applied to the tension roller 22 and the tension roll 22 that also serves as a backup roll is grounded.
Furthermore, a cleaning roll 26 serving as a belt cleaning device is disposed at a portion of the intermediate transfer belt 20 that faces the stretching roll 23. A predetermined cleaning bias is applied to the cleaning roll 26, and the stretching roll 23 is stretched. The roll 23 is grounded.
A recording medium 40 such as paper is accommodated in a supply tray 41, supplied by a pickup roll 42, guided to a secondary transfer portion through a registration roll 43, and then to a fixing device 45 through a conveyance belt 44. It is conveyed and discharged to a discharge tray 48 via a transfer roll 46 and a discharge roll 47.

Next, the operation of such an image forming apparatus will be described.
In FIG. 5, when the image forming apparatus starts an image forming operation, each color component toner image on the photosensitive drum 10 is sequentially formed and is primarily transferred onto the intermediate transfer belt 20 sequentially by the transfer electric field of the primary transfer roll 25.
Thereafter, the toner image primarily transferred to the intermediate transfer belt 20 is secondarily transferred to the recording medium 40 by the transfer electric field of the secondary transfer roll 30, and is carried to the fixing step.

  The semiconductive belt of the present invention used as the intermediate transfer belt 20 in this embodiment can prevent the bleed phenomenon even when the photosensitive drum 10 and the intermediate transfer belt 20 are always in contact with each other. A retract mechanism that separates the body drum 10 and the intermediate transfer belt 20 is not necessary, and the cost can be reduced.

Furthermore, in this embodiment, when the intermediate transfer belt 20 is driven to rotate by driving the photosensitive drum 10, the drive control cost of the intermediate transfer belt 20 can be greatly reduced.
Furthermore, since the contact width of the intermediate transfer belt 20 to the photosensitive drum 10 in the primary transfer can be set to be very wide, for example, 50 mm or more, stable follow-up to the intermediate transfer belt 20 can be realized, and the transfer nip region can be realized. Since there is no useless gap before and after, primary transfer is performed in a state where there is no scattering of toner due to discharge.
In particular, in this embodiment, since a wide transfer nip area between the photosensitive drum 10 and the intermediate transfer belt 20 can be secured, in this case, the pressure in the transfer nip area can be reduced. The situation in which the intermediate transfer belt 20 and the intermediate transfer belt 20 are in close contact with each other is more reliably avoided.

  In the image forming apparatus shown in FIG. 5, the photosensitive drum 10 and the intermediate transfer belt 20 are placed in contact with each other in an overlapping state, and as described above, the intermediate transfer belt 20 is in contact with the photosensitive drum 10. However, the present invention is not limited to this, and the photosensitive drum 10 and the intermediate transfer belt 20 have separate driving systems, and the photosensitive drum is not limited to this. The present invention can also be applied to an aspect in which the intermediate transfer belt 20 is brought into line contact with 10.

Next, the image forming apparatus shown in FIG. 6 is a color image forming apparatus that uses the semiconductive belt of the present invention as the intermediate transfer belt 102 and sequentially repeats the primary transfer.
The image forming apparatus includes a photosensitive drum 101 as an image carrier, an intermediate transfer belt 102, a bias roll 103 (secondary transfer roll) as a transfer electrode, a paper tray 104 for supplying recording paper as a recording medium, and Bk ( Developing unit 105 using black toner, developing unit 106 using Y (yellow) toner, developing unit 107 using M (magenta) toner, developing unit 108 using C (cyan) toner, intermediate transfer body cleaner 109, peeling claw 113, belt roll 121, 123 and 124, backup roll 122, conductive roll 125 (primary transfer roll), electrode roll 126, static elimination roll 130, cleaning blade 131, recording medium (recording paper) 141, pickup roll 142, and feed roll 143 Do it.

  In FIG. 6, the photosensitive drum 101 rotates in the direction of arrow A, and the surface thereof is uniformly charged by a charging device (not shown). An electrostatic latent image of the first color (for example, Bk) is formed on the charged photosensitive drum 101 by image writing means such as a laser writing device. The electrostatic latent image is developed with toner by the black developing device 105 to form a visualized toner image T. The toner image T reaches the primary transfer portion where the conductive roll 125 (primary transfer roll) is arranged by the rotation of the photosensitive drum 101, and an electric field having a reverse polarity is applied to the toner image T from the conductive roll 125. The toner image T is primarily transferred by the rotation of the intermediate transfer belt 102 in the direction of arrow B while being electrostatically attracted to the intermediate transfer belt 102.

Thereafter, similarly, a second color toner image, a third color toner image, and a fourth color toner image are sequentially formed and superimposed on the intermediate transfer belt 102 to form a multiple toner image.
The multiple toner image transferred to the intermediate transfer belt 102 reaches the secondary transfer portion where the bias roll 103 (secondary transfer roll) is installed by the rotation of the intermediate transfer belt 102. The secondary transfer unit includes a bias roll 103 installed on the surface side where the toner image of the intermediate transfer belt 102 is carried, a backup roll 122 disposed so as to face the bias roll 103 from the back side of the intermediate transfer belt 102, and The electrode roll 126 is configured to press and rotate against the backup roll 122.

  The recording paper 141 is picked up one by one from the recording paper bundle stored in the paper tray 104 by the pickup roll 142, and is fed at a predetermined timing between the intermediate transfer belt 102 and the bias roll 103 of the secondary transfer section by the feed roll 143. It is sent by. The toner image carried on the intermediate transfer belt 102 is transferred to the fed recording paper 141 by the pressure contact conveyance by the bias roll 103 and the backup roll 122 and the rotation of the intermediate transfer belt 102.

  The recording paper 141 onto which the toner image has been transferred is peeled off from the intermediate transfer belt 102 by operating the peeling claw 113 in the retracted position until the primary transfer of the final toner image is completed, and is conveyed to a fixing device (not shown). The toner image is fixed by heat treatment to be a permanent image. The intermediate transfer belt 102 after the transfer of the multiple toner image to the recording paper 141 has been removed by the intermediate transfer body cleaner 109 provided on the downstream side of the secondary transfer portion to prepare for the next transfer. The bias roll 103 is attached so that a cleaning blade 131 made of polyurethane or the like is always in contact therewith, and foreign matters such as toner particles and paper dust adhered by transfer are removed.

In the case of transfer of a single color image, the toner image T that has been primarily transferred is immediately subjected to secondary transfer, and the recording paper 141 is conveyed to the fixing device. Are synchronized with each other at the primary transfer portion to synchronize the rotation of the intermediate transfer belt 102 and the photosensitive drum 101 so that the toner images of the respective colors do not shift. In the secondary transfer section, an output pressure (transfer voltage) having the same polarity as the polarity of the toner image is applied to an electrode roll 126 that is in pressure contact with a backup roll 122 disposed opposite to the bias roll 103 via the intermediate transfer belt 102. The toner image is transferred to the recording paper 141 by electrostatic repulsion. Further, the charge on the intermediate transfer belt 102 is neutralized by a static elimination roll (static elimination means) 130. As the static elimination roll 130, an elastic roll (for example, an epichlorohydrin rubber roll with carbon black dispersion) can be used by dispersing a conductive agent whose volume resistance is adjusted to 10 ⁵ to 10 ¹⁰ Ω. The neutralizing roll 130 is disposed between the bias roller 103 and the peeling claw 113 on the intermediate transfer belt 102 in FIG. 6, but between the peeling claw 113 and the intermediate transfer body cleaner 109, or between the intermediate transfer body. You may arrange | position between the cleaner 109 and the electroconductive roller 125 etc.
With the image forming apparatus having the above-described configuration, a high-quality transfer image can be stably obtained.

Further, the image forming apparatus shown in FIG. 7 uses the semiconductive belt of the present invention as the intermediate transfer belt 86, and has a developing device 85 for each color and the same number of image carriers 79, and each image carrier. This is a color image forming apparatus in which primary transfer is sequentially repeated from the body 79 to the intermediate transfer belt 86.
In FIG. 7, a photosensitive drum (image carrier) 79 for each color including a developing device 85 for four colors (for example, black, yellow, magenta, and cyan) is disposed on the intermediate transfer belt 86. Specifically, in FIG. 7, a charging roll 83 (charging device) that uniformly charges the surface of the photosensitive drum 79, a laser generator 78 (exposure device) that exposes the surface of the photosensitive drum 79 to form an electrostatic latent image, The latent image formed on the surface of the photosensitive drum 79 is developed with toner, and a developing device 85 (developing device) that forms a toner image, and a photosensitive cleaner 84 (cleaning) that removes toner, dust, and the like attached to the photosensitive member. Apparatus), a fixing roll 72 for fixing the toner image on the recording medium, and the like can be optionally provided by a known method if necessary. Further, the charge on the intermediate transfer belt 86 is neutralized by a static elimination roll (static elimination means) 88. The neutralizing roll 88 is disposed between the secondary transfer roller 75 on the intermediate transfer belt 86 and the intermediate transfer body cleaner 82 in FIG. 7, but between the intermediate transfer body cleaner 82 and the primary transfer roller 80. It doesn't matter.
With the tandem image forming apparatus having the above-described configuration, a high-quality transfer image can be stably obtained.

FIG. 8 shows an image forming apparatus having a plurality of image carriers 201 and the same number of intermediate transfer belts 203.
The image forming apparatus includes an image carrier 201 for each color (four colors in the present embodiment), the same number of intermediate transfer belts 203 as the image carriers 201 arranged so as to be in contact with each image carrier, A sheet conveying belt 221 disposed in contact with the intermediate transfer belt 203. A toner image for each color is formed on each image carrier 201, the toner image is primarily transferred to each intermediate transfer belt 203, and then secondary transfer is sequentially performed to the recording medium 205 conveyed by the paper conveyance belt 221. .

  As shown in FIG. 8, each intermediate transfer belt 203 is stretched around a plurality of stretching rolls 211, 213, 215, and 217, and is in contact with the shape of a drum-shaped image carrier 201. preferable. By causing the intermediate transfer belt 203 to follow the shape of the image carrier 201 as much as possible, discharge due to useless gaps before and after the nip area during transfer can be eliminated, and toner image scattering (blurring) can be prevented.

  Further, it is preferable that each image carrier 201 and each intermediate transfer belt 203 has one of them as a drive source and the other driven to rotate. Furthermore, it is preferable that one of the two drive sources and the paper transport belt 221 is a drive source and the others are driven to rotate. By adopting such a drive configuration, one of the drive mechanisms can be omitted, and the drive cost can be reduced correspondingly, and the image carrier 201 and the intermediate transfer belt 203, or the intermediate transfer belt 203 and the paper conveyance. Variation factors such as variation in the thickness of the semiconductive belt (intermediate transfer belt) 203 caused by drive interference with the belt 221 and variation in feed in the process direction can be excluded.

  In the image forming apparatus shown in FIG. 8, even if the semiconductive belt of the present invention is not used as the intermediate transfer belt, the secondary transfer is not performed collectively after the toners of all colors are superimposed. However, since it is performed for each color, there is an advantage that the total charge amount of the toner can be reduced.

Here, the image forming method of the present invention will be mentioned.
The image forming method of the present invention includes a toner image forming step for forming a toner image on each of a plurality of image carriers, and each intermediate transfer belt disposed so as to be in contact with each image carrier. A primary transfer step for primary transfer of the toner image, and a toner image primarily transferred for each intermediate transfer belt on a recording medium conveyed by a paper conveyance belt disposed so as to be in contact with all the intermediate transfer belts. An image forming method having a secondary transfer step of performing next transfer, for example, an embodiment using an image forming apparatus as shown in FIG.
In the above image forming method, since the semiconductive belt of the present invention is used as an intermediate transfer belt, the belt is particularly used even in a recording medium having a surface unevenness difference of 40 to 60 μm and a thickness of 100 to 260 μm. Follows the unevenness, and a good transfer image can be obtained. In addition, since the application of the transfer voltage in the secondary transfer step is controlled to be performed after the intermediate transfer belt and the recording medium are in contact with each other, it is possible to suppress toner scattering that occurs near the secondary transfer portion. it can. Further, since the secondary transfer is not performed at once after the toners of all colors are superimposed, but is performed for each color, there is an advantage that the total charge amount of the toner can be reduced.

(toner)
Further, when the semiconductive belt of the present invention is incorporated and used as an intermediate transfer belt or transfer / conveying belt in an image forming apparatus, it is preferable to use a spherical toner. By using spherical toner as the toner, the material constituting the transfer surface has a low surface hardness and high volume resistance, thereby obtaining a high-quality transfer image quality free from image quality defects (holocharacter, blur, color registration). be able to.

However, the spherical toner means that the shape factor SF is 140 to 100. The shape factor is preferably 130 to 100 or less, and more preferably 120 to 100 or less. When the average shape factor SF is larger than 140, the transfer efficiency is lowered, and the deterioration of the image quality of the print sample can be visually confirmed.
Here, the shape factor SF is a factor defined by the following equation.
SF = (maximum length of toner particles) ² / (projected area of toner particles) × (π / 4) × 100
The maximum length of toner particles and the projected area of the toner particles are measured using a Luzex image analysis apparatus (manufactured by Nireco Co., Ltd., FT) using an optical microscope image of the toner dispersed on a slide glass through a video camera. This was carried out by importing into an image analyzer and processing the image.

  The spherical toner contains at least a binder resin and a colorant. The spherical toner may preferably use 2 to 12 μm particles, more preferably 3 to 9 μm particles.

  Binder resins include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene and isoprene, vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl butyrate, and methyl acrylate. , Α-methylene aliphatic monocarboxylic esters such as ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate, vinyl Homopolymers and copolymers of vinyl ethers such as methyl ether, vinyl ethyl ether, and vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone can be exemplified. Typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer. , Polyethylene, polypropylene and the like. Furthermore, polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax, and the like can be given.

  Coloring agents include magnetic powders such as magnetite and ferrite, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, and lamp black. Rose Bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 17, C.I. I. Pigment blue 15: 1, C.I. I. Pigment Blue 15: 3 is a typical example.

  The spherical toner may be subjected to internal addition treatment or external addition treatment with a known additive such as a charge control agent, a release agent, and other inorganic fine particles. Typical examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

  Known charge control agents can be used, but azo metal complex compounds, metal complex compounds of salicylic acid, and resin type charge control agents containing polar groups can be used. When the toner is manufactured by a wet manufacturing method, it is preferable to use a material that is difficult to dissolve in water in terms of controlling ionic strength and reducing wastewater contamination.

As other inorganic fine particles, small-diameter inorganic fine particles having an average primary particle size of 40 nm or less are used for the purpose of powder flowability, charge control, etc., and if necessary, larger diameters are used to reduce adhesion. These inorganic or organic fine particles may be used in combination. As these other inorganic fine particles, known ones can be used. Examples thereof include silica, alumina, titania, metatitanic acid, zinc oxide, zirconia, magnesia, calcium carbonate, magnesium carbonate, calcium phosphate, cerium oxide, and strontium titanate.
In addition, the surface treatment of the small-diameter inorganic fine particles is effective because the dispersibility becomes high and the effect of increasing the powder fluidity increases.

  The spherical toner is not particularly limited by the production method, and can be obtained by a known method. Specifically, for example, a kneading and pulverizing method in which a binder resin and a colorant and, if necessary, a release agent and a charge control agent are kneaded, pulverized and classified, and particles obtained by the kneading and pulverizing method are mechanically Method of changing shape by force or heat energy, emulsion polymerization of binder resin polymerizable monomer, dispersion of formed dispersion, colorant, release agent and charge control agent as required Liquid emulsion, agglomeration, heat fusion to obtain spherical toner, emulsion polymerization aggregation method, polymerizable monomer for obtaining binder resin, colorant, release agent if necessary, charge control agent A suspension polymerization method in which a solution such as a suspension is polymerized by suspending in an aqueous solvent, a binder resin and a colorant, and a release agent and a charge control agent as necessary are suspended in an aqueous solvent and granulated. Examples thereof include a dissolution suspension method. Further, a manufacturing method may be performed in which the spherical toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure. When the external additive is added, it can be produced by mixing the spherical toner and the external additive with a Henschel mixer or a V blender. In addition, when the spherical toner is manufactured by a wet method, it can be externally added by a wet method.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “parts” and “%” represent “parts by mass” and “mass%” unless otherwise specified.

Example 1
(Substrate material)
As a tetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) are combined in a ratio of 2: 1 to obtain a diamine. As a component, N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 4,4′-diaminodiphenyl ether (DDE) (20% solid content) and dried oxidized carbon black (SPECIAL BLACK4, Degussa) Manufactured, pH 3.0, volatile content: 14.0%) is added so as to be 24 parts with respect to 100 parts of the polyimide resin solid content, and using a collision type disperser (Geanus PY made by Seanas) at a pressure of 200 MPa, minimum area is allowed to collide after two split 1.4 mm ^2, is passed through the path 5 times to 2 again divided, mixed and Kabonbu for substrate Tsu obtain click-containing polyamic acid solution (A).

(Outermost layer material)
As the outermost layer material, 100 parts of Coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as the isocyanate and 93 parts of Nipponran 4599 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as the polyol, and carbon black ( Product name: Printex 140U (pH 4.5%): Degussa Japan Co., Ltd.) 18 parts, and as a lubricious filler, fluororesin powder having an average particle size of 0.2 μm (Lublon L-5: manufactured by Daikin Industries, Ltd.) ) 20 parts were mixed to prepare the outermost layer material (A).

(Formation of a two-layer belt)
The polyamic acid solution (A) is applied to the inner surface of the cylindrical mold to 0.4 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm, After applying hot air of 60 ° C. from the outside of the mold for 30 minutes, heating at 150 ° C. for 60 minutes, returning to room temperature, peeling off from the mold, and then covering the metal core to 2 ° C./360° C. The temperature was raised at a rate of minutes, and further heated at 360 ° C. for 30 minutes to remove the solvent, dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature and peeled from the mold to obtain a target polyimide film. The film thickness was 0.08 mm. The Young's modulus of this film was 2500 MPa, and the volume resistivity at an applied voltage of 100 V was 5 × 10 ¹⁰ Ωcm.

Cover the above-mentioned polyimide film on a cylindrical mold, apply the coating solution of the outermost layer material (A), and heat at a temperature of 80 ° C. for 120 minutes to cure the outermost thermosetting urethane layer. Thus, a two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.13 mm was obtained. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.08 mm for the base material. The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 7.0 × 10 ¹¹ Ωcm. The surface D hardness was 30. The surface roughness Rz was 6 μm.

-Example 2-
(Material for base material and outermost layer)
The material of the base material is the same material as in Example 1. As the outermost layer material, as isocyanate, 100 parts of coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) and as polyol, Nipponran 4378 (Nippon Polyurethane Industry Co., Ltd.) 80 parts of carbon black (trade name: Printex 140U (pH 4.5%): manufactured by Degussa Japan Co., Ltd.) 18 parts as a conductive agent, and an average particle diameter of 0.2 μm as a lubricating filler. The outermost layer material (B) was prepared by mixing 22 parts of fluororesin powder (Lublon L-5: manufactured by Daikin Industries, Ltd.).

(Formation of a two-layer belt)
A cylindrical mold is coated with the polyimide film obtained by the same method as in Example 1, and the outermost layer material (B) coating solution is applied, heated at 80 ° C. for 120 minutes, and the outermost layer is coated. A two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.13 mm was obtained by curing the thermosetting urethane layer. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.08 mm for the base material.
The volume resistivity of the outermost layer at an applied voltage of 100 V was 9.0 × 10 ¹¹ Ωcm. The surface D hardness was 52. The surface roughness Rz was 7 μm.

Example 3
(Substrate material)
N-methyl-2-pyrrolidone (NMP) solution of polyamic acid composed of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and 4,4′-diaminodiphenyl ether (DDE) (Ube Kowanu Euvarnish A; solid content 20%) and dried oxidized carbon black (SPECIAL BLACK4, manufactured by Degussa, pH 3.0, volatile content: 14.0%) with respect to 100 parts of polyimide resin solid content, Add to 26 parts, and use a collision type disperser (GeanusPY manufactured by Seanas), collide after splitting into 2 parts with a pressure of 200 MPa and a minimum area of 1.4 mm ² , and again pass through the path that splits into 2 parts 5 times. To obtain a polyamic acid solution (B) containing carbon black for the substrate.

(Outermost layer material)
As the outermost layer material, 100 parts of Coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 80 parts of Nipponran 4378 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black ( Product name: Printex 140U (pH 4.5%): Degussa Japan Co., Ltd.) 10 parts, and as a lubricating filler, fluororesin powder having an average particle size of 0.2 μm (Lublon L-5: manufactured by Daikin Industries, Ltd.) ) 30 parts were mixed to prepare the outermost layer material (C).

(Formation of a two-layer belt)
The polyamic acid solution containing carbon black (B) is applied to the inner surface of the cylindrical mold to 0.4 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm. However, after applying hot air of 60 ° C. for 30 minutes from the outside of the mold, it was heated at 150 ° C. for 60 minutes, returned to room temperature, peeled off from the mold, coated on the metal core, and 2 ° C. until 360 ° The temperature was raised at a rate of temperature rise / minute, and further heated at 400 ° C. for 30 minutes to remove the solvent, remove the dehydrated ring-closing water, and complete the imide conversion reaction. Thereafter, the temperature was returned to room temperature and peeled from the mold to obtain a target polyimide film. The thickness of the film was 0.08 mm. The Young's modulus of this resin belt was 3800 MPa, and the volume resistivity at an applied voltage of 100 V was 5 × 10 ¹⁰ Ωcm.

Cover the above-mentioned polyimide film on a cylindrical mold, apply the coating solution of the outermost layer material (C), and heat at a temperature of 80 ° C. for 120 minutes to cure the outermost thermosetting urethane layer. Thus, a two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.14 mm was obtained. The thickness of each layer of this belt was 0.06 mm for the outermost layer and 0.08 mm for the base material.
The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 1 × 10 ¹³ Ωcm. The surface D hardness was 55. The surface roughness Rz was 9 μm.

Example 4
(Material for base material and outermost layer)
The material of the base material is the same material as in Example 1. As the outermost layer material, as isocyanate, 100 parts of coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) and as polyol, Nipponran 4378 (Nippon Polyurethane Industry Co., Ltd.) 80 parts of carbon black (trade name: Printex 140U (pH 4.5%): manufactured by Degussa Japan Co., Ltd.) 10 parts, and an average particle diameter of 0.2 μm The outermost layer material (D) was prepared by mixing 10 parts of fluororesin powder (Lublon L-5: manufactured by Daikin Industries, Ltd.).

(Formation of a two-layer belt)
A cylindrical mold is coated with the polyimide film obtained by the same method as in Example 1, and the outermost layer material (D) coating solution is applied, heated at 80 ° C. for 120 minutes, and outermost layer is coated. The two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.13 mm was obtained by curing the thermosetting urethane layer. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.08 mm for the base material.
The volume resistivity of the outermost layer at an applied voltage of 100 V was 1 × 10 ¹³ Ωcm. The surface D hardness was 49. The surface roughness Rz was 1.5 μm.

-Example 5
(Material for base material and outermost layer)
As a base material, 100 parts of polyvinylidene fluoride resin (manufactured by Kureha Chemical Industry Co., Ltd .: trade name “# 850”) as a conductive agent, oxidized carbon black (trade name: Printex 140U (pH 4.5%): 16 parts) was added, dispersed and kneaded with a twin-screw extruder, the resin composition was used, and a single-screw extruder was used to produce a 0.12 mm thick resin belt. . This resin belt had a volume resistivity of 1.0 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The Young's modulus was 1900 MPa.
As the material for the outermost layer, the coating liquid of the material for outermost layer (A) was used as in Example 1.

(Formation of a two-layer belt)
Cover the cylindrical belt with the resin belt obtained above, apply the coating solution of the outermost layer material (A), and heat at a temperature of 80 ° C. for 120 minutes to form the outermost thermosetting urethane layer. Was cured to obtain a two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.17 mm. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.12 mm for the base material.
The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 7.0 × 10 ¹¹ Ωcm. The surface D hardness was 30. The surface roughness Rz was 6 μm.

-Example 6
(Material for base material and outermost layer)
As a base material, 100 parts of vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Kureha Chemical Industry Co., Ltd .: trade name “# 2300”) as a conductive agent, oxidized carbon black (trade name: Printex 140U ( pH 4.5%): Degussa Japan Co., Ltd.) 15 parts was added, and the resin composition was dispersed and kneaded with a twin screw extruder, and further, a thickness of 0.12 mm using a single screw extruder. A resin belt was prepared. This resin belt had a volume resistivity of 5 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The Young's modulus was 1500 MPa.
As the material for the outermost layer, the coating liquid of the material for outermost layer (C) was used as in Example 3.

(Formation of a two-layer belt)
Cover the cylindrical belt with the resin belt obtained above, apply the coating liquid of the outermost layer material (C), and heat at a temperature of 80 ° C. for 120 minutes to form the outermost thermosetting urethane layer. Was cured to obtain a two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.17 mm. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.12 mm for the base material.
The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 1 × 10 ¹³ Ωcm. The surface D hardness was 55. The surface roughness Rz was 9 μm.

-Example 7-
(Material for base material and outermost layer)
As a base material, 15 parts of ketjen black was added to 100 parts of polypropylene (Idemitsu Kosan Co., Ltd. RB110 (trade name)), and dispersed and kneaded with a twin screw extruder to obtain pellets of a resin composition. . Further, a resin belt having a thickness of 0.15 mm was produced using a single screw extruder. This resin belt had a volume resistivity of 5 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The Young's modulus was 950 Mpa.
As the material for the outermost layer, the coating liquid of the material for outermost layer (A) was used as in Example 1.

(Formation of a two-layer belt)
Cover the cylindrical belt with the resin belt obtained above, apply the coating solution of the outermost layer material (A), and heat at a temperature of 80 ° C. for 120 minutes to form the outermost thermosetting urethane layer. Was cured to obtain a two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.17 mm. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.12 mm for the base material.
The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 7.0 × 10 ¹¹ Ωcm. The surface D hardness was 30. The surface roughness Rz was 6 μm.

-Comparative Example 1-
(Material for base material and outermost layer)
The material of the base material is the same material as in Example 6. As the material of the outermost layer, as isocyanate, 100 parts of coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) and as polyol, Nipponran 4599 (Nippon Polyurethane Industry Co., Ltd.) 93 parts and carbon black (trade name: Printex 140U (pH 4.5%): Degussa Japan Co., Ltd.) 6 parts as a conductive agent are mixed to prepare the outermost layer material (E). did.

(Formation of a two-layer belt)
A cylindrical mold is covered with a resin belt obtained by the same method as in Example 6, and a coating solution of the outermost layer material (E) is applied, heated at 80 ° C. for 120 minutes, and outermost layer is coated. The two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.17 mm was obtained by curing the thermosetting urethane layer. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.12 mm for the base material. The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 1 × 10 ¹³ Ωcm. The surface D hardness was 28. The surface roughness Rz was 0.9 μm.

-Comparative Example 2-
(Preparation of materials for substrate and outermost layer)
The same material as in Example 6 was used as the base material, 100 parts of coronate 437048 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as the material of the outermost layer, and NIPPOLAN 4038 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as the polyol 15 As a conductive agent, 20 parts of carbon black (trade name: Printex 140U (pH 4.5%): manufactured by Degussa Japan), fluororesin powder having an average particle size of 0.2 μm (Lublon L-5: Daikin Industries, Ltd. (50 parts) was mixed to prepare the outermost layer material (F).

(Formation of a two-layer belt)
A cylindrical mold is covered with a resin belt obtained by the same method as in Example 6, and a coating liquid of the outermost layer material (F) is applied, heated at 80 ° C. for 120 minutes, and the outermost layer is coated. The two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.17 mm was obtained by curing the thermosetting urethane layer. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.12 mm for the base material.
The volume resistivity of the outermost layer of this belt at an applied voltage of 100 V was 7.0 × 10 ¹⁰ Ωcm. The surface D hardness was 77. The surface roughness Rz was 11 μm.

-Comparative Example 3-
(Material for base material and outermost layer)
The material of the base material is the same material as in Example 1. As the outermost layer material, as isocyanate, 100 parts of coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) and as polyol, Nipponran 4038 (Nippon Polyurethane Industry Co., Ltd.) 15 parts of carbon black (trade name: Printex 140U (pH 4.5%): manufactured by Degussa Japan Co., Ltd.), and 15 parts of an average particle diameter of 0.2 μm. The outermost layer material (G) was prepared by mixing 20 parts of fluororesin powder (Lublon L-5: manufactured by Daikin Industries, Ltd.).

(Formation of a two-layer belt)
A cylindrical mold is covered with the polyimide film obtained by the same method as in Example 1, and the coating solution of the outermost layer material (G) is applied, heated at 80 ° C. for 120 minutes, and the outermost layer is coated. A two-layer belt having an inner diameter of 168 mm, a width of 350 mm, and a thickness of 0.13 mm was obtained by curing the thermosetting urethane layer. The thickness of each layer of this belt was 0.05 mm for the outermost layer and 0.08 mm for the base material.
The volume resistivity of the outermost layer at an applied voltage of 100 V was 1 × 10 ¹³ Ωcm. The surface D hardness was 75. The surface roughness Rz was 6 μm.

<Evaluation>
For the semiconductive belts obtained in Examples 1 to 7 and Comparative Examples 1 to 3, transfer image quality (blur, holocharacter, color registration), embossed paper runnability, and image quality after 3000 copies of postcards were evaluated. . These results are shown in Table 1.

(Evaluation of transfer image quality)
The obtained semiconductive belt was modified from Fuji Xerox Co., Ltd., Docu Color 1255CP, and mounted on the image forming apparatus having the configuration shown in FIG.

(1) Blur evaluation The occurrence of blur was evaluated according to the following criteria.
◎: No blurring ○: Bluring is slight and there is no problem in image quality ×: Bluring occurs and there is a problem in image quality

(2) Holocharacter evaluation The occurrence of holocharacters was evaluated according to the following criteria.
◎: No image quality problem ○: Slight occurrence, few image quality problems ×: Image quality problem

(3) Color registration evaluation The occurrence of registration misalignment was evaluated according to the following criteria.
◎: No image quality problem ○: Slight occurrence, few image quality problems △: Occurrence but few image quality problems ×: Image quality problems

(Embossed paper runnability)
The image quality was evaluated when a halftone of 30% magenta was copied by running an embossed paper with a step of 50 μm, and evaluated according to the following criteria.
◎: Image quality problem in continuous 1000-sheet running test ○: No significant image quality problem in continuous 1000-sheet running test ×: Image quality problem

(Continuous running)
After 3000 copies of postcards were continuously copied, the occurrence of white spots when copying a halftone of 30% magenta was evaluated according to the following criteria.
○: No white spot occurs ×: White spot occurs and there is a problem in image quality

  From the results of Table 1, the semiconductive belts of Examples 1 to 7 of the present invention were free from image quality defects and could stably obtain excellent image quality over a long period of time. In particular, in Examples 3 and 6 in which the outermost layer had a high volume resistivity, high image quality without blurring was obtained. On the other hand, in Comparative Example 1, since the hardness of the outermost layer material was low, white image quality defects occurred in the paper running test. In Comparative Examples 2 and 3, since the surface hardness was hard, a holocharacter image quality defect occurred, and there was a problem in the running property of the embossed paper.

-Example 8-
(Preparation of material (A))
As the material (A), 100 parts of Coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 93 parts of Nipponran 4599 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black ( Product name: Printex 140U (pH 4.5: manufactured by Degussa Japan Co., Ltd.) 18 parts, and a fluororesin powder having an average particle size of 0.2 μm as a lubricating filler (Lublon L-5: manufactured by Daikin Industries, Ltd.) Prepared by mixing 20 parts.

(Belt formation)
The coating liquid of the material (A) is applied to a cylindrical mold, heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer, and has an inner diameter of 140 mm, a width of 320 mm, and a thickness of 0.3 mm. A construction belt was obtained. The belt had a volume resistivity of 1 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface D hardness was 30. The surface roughness Rz was 6 μm.

-Example 9-
(Preparation of material (B))
As the material (B), 100 parts of Coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as an isocyanate and 80 parts of Nipponran 4378 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a polyol, and carbon black ( Product name: Printex 140U (pH 4.5: manufactured by Degussa Japan Co., Ltd.) 18 parts, and a fluororesin powder having an average particle size of 0.2 μm as a lubricating filler (Lublon L-5: manufactured by Daikin Industries, Ltd.) 10 parts were mixed and prepared.

(Belt formation)
The coating liquid of the material (B) is applied to a cylindrical mold, heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer, and has an inner diameter of 140 mm, a width of 320 mm, and a thickness of 0.3 mm. A construction belt was obtained. The belt had a volume resistivity of 3 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface D hardness was 49. The surface roughness Rz was 1.5 μm.

-Example 10-
(Preparation of material (C))
As the material (C), 100 parts of Coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 80 parts of Nipponran 4378 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black ( Product name: Printex 140U (pH 4.5: manufactured by Degussa Japan Co., Ltd.) 18 parts, and a fluororesin powder having an average particle size of 0.2 μm as a lubricating filler (Lublon L-5: manufactured by Daikin Industries, Ltd.) Prepared by mixing 18 parts.

(Belt formation)
A coating solution of the material (C) is applied to a cylindrical mold and heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer. A construction belt was obtained. The belt had a volume resistivity of 4 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface D hardness was 55. The surface roughness Rz was 4.5 μm.

-Example 11-
(Preparation of material (D))
As the material (D), 100 parts of Coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 93 parts of Nipponran 4599 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black ( (Product name: Printex 140U (pH 4.5): Degussa Japan Co., Ltd.) 20 parts, and as a filler, a fluororesin powder having an average particle size of 0.2 μm (Lublon L-5: manufactured by Daikin Industries, Ltd.) 30 parts were mixed and prepared.

(Belt formation)
The coating liquid of the material (D) is applied to a cylindrical mold, heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer, and has an inner diameter of 140 mm, a width of 320 mm, and a thickness of 0.3 mm. A construction belt was obtained. The belt had a volume resistivity of 8 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The surface D hardness was 42. The surface roughness Rz was 9 μm.

-Comparative Example 4-
(Preparation of material (E))
As the material (E), 100 parts of Coronate 4370 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 15 parts of Nipponran 4038 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black ( Product name: Ketjen Black (pH 9): Lion Azo Co., Ltd.)) 8 parts, and as a filler, a fluororesin powder having an average particle size of 0.2 μm (Lublon L-5: Daikin Industries, Ltd.) 10 Parts were mixed and prepared.

(Belt formation)
A coating solution of the material (E) is applied to a cylindrical mold, heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer, and has an inner diameter of 140 mm, a width of 320 mm, and a thickness of 0.3 mm. A construction belt was obtained. The belt had a volume resistivity of 3 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface D hardness was 75. The surface roughness Rz was 1.3 μm.

-Comparative Example 5-
(Preparation of material (F))
As the material (F), 100 parts of Coronate 4028 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 93 parts of Nipponran 4599 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol and carbon black ( A product name: 13 parts of granular acetylene black (pH 4.5: manufactured by Electrochemical Co., Ltd.) was mixed to prepare.

(Belt formation)
A coating solution of the material (F) is applied to a cylindrical mold and heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer. A construction belt was obtained. The belt had a volume resistivity of 8 × 10 ¹¹ Ωcm at an applied voltage of 100V. The surface D hardness was 28. The surface roughness Rz was 0.9 μm.

-Comparative Example 6
(Preparation of material (G))
As material (G), 100 parts of Coronate 437048 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as isocyanate and 15 parts of Nipponan 4038 (manufactured by Nippon Polyurethane Industry Co., Ltd.) as polyol, and carbon black ( Product name: Granular acetylene black (pH4.5): 20 parts by Electrochemical Co., Ltd., and 50 parts of fluororesin powder (Lublon L-5: Daikin Industries, Ltd.) with an average particle size of 0.2 μm are mixed. Thus, an outermost layer material (E) was prepared.

(Belt formation)
A coating liquid of the material (G) is applied to a cylindrical mold, heated at a temperature of 80 ° C. for 120 minutes to cure the thermosetting urethane layer, and has an inner diameter of 140 mm, a width of 320 mm, and a thickness of 0.3 mm. A construction belt was obtained. The belt had a volume resistivity of 5 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The surface D hardness was 78. The surface roughness Rz was 12 μm.

-Comparative Example 7-
70 parts of chloroprene rubber is masticated for 2 minutes using a 6 inch diameter open roll, and 30 parts of ethylene / propylene / non-conjugated diene terpolymer (EPDM) is added thereto and kneaded for 13 minutes. It was. Next, 5 parts of zinc oxide, 4 parts of magnesium oxide, 1 part of stearic acid, and 0.35 part of Sunseller 22C (ethylene thiourea manufactured by Sanshin Chemical Co., Ltd.) are sequentially added to the polymer kneaded product of chloroprene rubber and EPDM. In addition, 1.5 parts of Noxarer BZ (Zinc di-n-butyl dithiocarbamate manufactured by Ouchi Shinko Co., Ltd.), 1 part of Noxeller DM (Dibenzothiazyl disulfide manufactured by Ouchi Shinko Co., Ltd.), Noxeller TRA (Ouchi Promotion) After adding 0.7 parts of dipentamethylene thiuram tetrasulfide) and 1.5 parts of sulfur, thinning was performed 10 times using an open roll. After the rubber kneaded material is removed from the open roll, it is divided into three equal parts, and 23 parts of furnace black (manufactured by Asahi Carbon Co., Ltd.) and 6 parts of Denka black (granular acetylene black produced by Electrochemical Co., Ltd.) are respectively added to the rubber kneaded materials. And kneaded with an open roll.
The kneaded material to which carbon black was added in this way was formed into a belt shape using an extruder, and then vulcanized using a steam kettle. Then, the thickness of the belt was processed to 0.5 mm by grinding. The belt surface was spray-coated with a mixture of 100 parts of C-230U base (polyester urethane manufactured by Hirono Kagaku) and 30 parts of C-230U curing agent (isocyanate manufactured by Hirono Kagaku) for 30 minutes at 160 ° C. Firing was performed to form an outermost layer, and a belt having an inner diameter of 140 mm and a width of 300 mm was produced.
The belt had a volume resistivity of 3.0 × 10 ¹⁰ Ωcm at an applied voltage of 100V. The surface D hardness was 25. The surface roughness Rz was 8.5 μm.

<Evaluation>
About the semiconductive belts obtained in Examples 8 to 11 and Comparative Examples 4 to 7, scratchability, occurrence of bleeding, transfer image quality (blur, holocharacter, color register), image quality after 3000 copies of postcards Was evaluated. These results are shown in Table 2.

(Scratch property)
Silica sand No. 4 (average particle size: about 1 mm) is placed on a belt in an amount of 0.5 g and printed. Thereafter, the belt is wiped clean with methyl alcohol and subjected to a color unevenness test to visually check the effect of scratches entering the belt on printing.
◎: No abnormality ○: Abnormally small, belt can be used continuously ×: Abnormally large, belt replacement required

(Bleedability)
The obtained semiconductive belt was brought into contact with the OPC photoreceptor for 2 weeks in a high-temperature and high-humidity environment (48 ° C., 90% RH), and image quality evaluation was evaluated using the OPC photoreceptor.
Judgment is
○: There is no problem in the transfer image quality ×: There is a problem in the transfer image quality at the part where the semiconductive belt is in contact (whiteout occurs)

(Evaluation of transfer image quality)
The obtained semiconductive belt was modified from Docu Color 1255CP of Fuji Xerox Co., Ltd. and mounted on the image forming apparatus having the configuration shown in FIG. 5 to evaluate the transfer image quality. The OPC photoconductor was used as the photoconductor.

(1) Blur evaluation The occurrence of blur was evaluated according to the following criteria.
○: No blurring or slight blurring, no problem in image quality ×: Bluring, problem in image quality

(2) Holocharacter evaluation The occurrence of holocharacters was evaluated according to the following criteria.
○: Occurrence is slight and there are few image quality problems ×: Image quality problems

(Continuous running)
After 3000 copies of postcards were continuously copied, the occurrence of white spots when copying a halftone of 30% magenta was evaluated according to the following criteria.
○: No white spot occurs ×: White spot occurs and there is a problem in image quality

  From the results shown in Table 2, the semiconductive belts of Examples 8 to 11 of the present invention were free from image quality defects and could stably obtain excellent image quality over a long period of time. On the other hand, in Comparative Example 4 and Comparative Example 6, since the surface hardness of the material was hard, image quality defects of blur and holographic characters occurred. Also, in the paper running test, white image quality defects occurred. In Comparative Example 5 and Comparative Example 6, since the surface hardness was soft, there was no problem due to the image quality defect of blur and holocharacter, but there was a problem in the scratch evaluation, and there was a foreign matter between the photoconductor and the belt. In some cases, problems such as the need to replace the belt may occur. Further, in Comparative Example 7, a so-called bleed phenomenon occurred in which a low molecular oil component dispersed in the belt base material was deposited on the surface of the conveyor belt.

-Example 12-
(Formation of conductive elastic layer)
Granular acetylene black [manufactured by Denki Kagaku Kogyo Co., Ltd .: oil absorption 288 ml / 100 g] with respect to 100 parts of a rubber material (NE40; manufactured by Nippon Synthetic Rubber Co., Ltd.) in which NBR and EPDM are blended at a mass ratio of 4: 6 A rubber composition having a mixing ratio of 10 parts and 20 parts of Asahi Thermal FT (Asahi Carbon Co., Ltd .: oil absorption 28 ml / 100 g and average particle size 80 μm) was kneaded with two rolls. The obtained kneaded material was formed into a tube shape by a tube cross head extruder. Subsequently, the molded blend rubber material was heated and vulcanized in a vulcanizing can with a pressurized steam at a temperature of 126 ° C. and a pressure of 1.5 kg / cm ² G to form a conductive belt material. The obtained belt material is placed on the outside of a metal tube, and the surface is polished to produce a rubber belt made of an elastic layer having a thickness of 0.5 mm, an inner diameter of 140 mm, a width of 320 mm, and a volume resistivity of 3 × 10 ⁹ Ωcm. did.
All volume resistivity values obtained by reading the current value 30 seconds after applying a voltage of 100 V using a resistance meter (HR probe from Hiresta IP; manufactured by Dia Instruments Co., Ltd.) It is.

(Formation of outermost layer)
The following composition was mixed with a ball mill to prepare a dispersion in which a conductive agent (antimony-doped tin oxide) and a solid lubricant (graphite fluoride) were uniformly dispersed in a fluororesin.
・ Copolymer resin of tetrafluoroethylene and vinyl ether: 100 parts
(Zeffle GK-500: manufactured by Daikin Industries, Ltd.)
・ Isocyanate cross-linking agent (Coronate HL: manufactured by Nippon Polyurethane Co., Ltd.) 2 parts Antimony-doped tin oxide (SN-100P: manufactured by Ishihara Sangyo Co., Ltd.) 20 parts graphite fluoride (Cefbon-CMA: Central Glass) (Made by company) ............ 5 parts The dispersion obtained is dip-coated on the surface of the elastic roller having the resistance layer formed on the surface, and then heated and dried to form a 2 μm-thick film made of a fluororesin film. The outermost layer was formed.
The volume resistivity of the semiconductive belt of Example 12 manufactured as described above is 8 × 10 ⁹ Ωcm, the contact angle of the belt surface is 120 degrees, and the ten-point average surface roughness Rz. Was 6.0 μm.

-Example 13-
A charging member was produced in the same manner as in Example 12 except that the blending amount of graphite fluoride was changed to 10 parts when forming the outermost layer. The volume resistivity of the semiconductive belt of the semiconductive belt portion of Example 13 obtained in this way is 3 × 10 ¹⁰ Ωcm, and the contact angle of the surface is 125 degrees. The point average surface roughness Rz was 9.0 μm.

-Example 14-
In forming the outermost layer, a semiconductive belt was produced in the same manner as in Example 12 except that the blending amount of the graphite fluoride was 3 parts and the dip coating was spray coating. The volume resistivity of the semiconductive belt of Example 14 obtained in this way is 7 × 10 ⁹ Ωcm, the contact angle of the surface is 115 degrees, and the ten-point average surface roughness Rz is It was 4.0 μm.

-Example 15-
A semiconductive belt was produced in the same manner as in Example 12 except that the blending amount of graphite fluoride was changed to 1.5 parts when forming the outermost layer. The volume resistivity of the semiconductive belt of Example 15 obtained in this way was volume resistivity 6 × 10 ⁹ Ωcm, the contact angle of the surface was 115 degrees, and the ten-point average surface roughness Rz was It was 1.5 μm.

-Comparative Example 8-
In the formation of the outermost layer, graphite fluoride was not blended, and instead of 20 parts of antimony-doped tin oxide, 11 parts of Ketjen Black made by Lion Aguzo Co., Ltd. was added as a conductive agent, in the same manner as in Example 12. A semiconductive belt was prepared. The semiconductive belt of Comparative Example 8 obtained in this way had a density of 5 × 10 ¹⁰ Ωcm, a surface contact angle of 102 degrees, and a ten-point average surface roughness Rz of 1.0 μm.

-Comparative Example 9-
Semiconductive in the same manner as in Example 12 except that 5 parts of molybdenum disulfide powder (Mori powder PS, manufactured by Sumiko Lubricant Co., Ltd.) was used as the solid lubricant instead of graphite fluoride when forming the outermost layer. A belt was produced. The semiconductive belt of Comparative Example 9 thus obtained was 7 × 10 ⁹ Ωcm, the contact angle of the surface was 98 degrees, and the ten-point average surface roughness Rz was 25 μm.

-Comparative Example 10-
70 parts of chloroprene rubber is masticated for 2 minutes using a 6 inch diameter open roll, and 30 parts of ethylene / propylene / non-conjugated diene terpolymer (EPDM) is added thereto and kneaded for 13 minutes. It was. Next, 5 parts of zinc oxide, 4 parts of magnesium oxide, 1 part of stearic acid, and 0.35 part of Sunseller 22C (ethylene thiourea manufactured by Sanshin Chemical Co., Ltd.) are sequentially added to the polymer kneaded product of chloroprene rubber and EPDM. In addition, 1.5 parts of Noxarer BZ (Zinc di-n-butyl dithiocarbamate manufactured by Ouchi Shinko Co., Ltd.), 1 part of Noxeller DM (Dibenzothiazyl disulfide manufactured by Ouchi Shinko Co., Ltd.), Noxeller TRA (Ouchi Promotion) After adding 0.7 parts of dipentamethylene thiuram tetrasulfide) and 1.5 parts of sulfur, thinning was performed 10 times using an open roll. After the rubber kneaded material is removed from the open roll, it is divided into three equal parts, and 23 parts of furnace black (manufactured by Asahi Carbon Co., Ltd.) and 6 parts of Denka black (granular acetylene black produced by Electrochemical Co., Ltd.) are respectively added to the rubber kneaded materials. And kneaded with an open roll.
The kneaded material to which carbon black was added in this way was formed into a belt shape using an extruder, and then vulcanized using a steam kettle. Then, the thickness of the belt was processed to 0.5 mm by grinding. The belt surface was spray-coated with a mixture of 100 parts of C-230U base (polyester urethane manufactured by Hirono Kagaku) and 30 parts of C-230U curing agent (isocyanate manufactured by Hirono Kagaku) for 30 minutes at 160 ° C. Firing was performed to form an outermost layer, and a belt having an inner diameter of 140 mm and a width of 300 mm was produced.
The semiconductive belt of Comparative Example 10 thus obtained was 6 × 10 ¹⁰ Ωcm, the surface contact angle was 85 degrees, and the ten-point average surface roughness Rz was 12 μm.

  The above water contact angle can be measured using a goniometer or the like. In the present invention, water is dropped on the surface of the semiconductive belt in an environment of 23 ° C. and 55% RH. The contact angle after standing for 10 seconds was measured using a contact angle measuring device CA-X roll type (manufactured by Kyowa Interface Science Co., Ltd.). In addition, the average value when the measurement was repeated three times at different locations was determined as the contact angle of the semiconductive belt.

<Evaluation>
About the semiconductive belts obtained in Examples 12 to 15 and Comparative Examples 8 to 10, occurrence of bleeding, transfer image quality (blur, holocharacter), image quality after continuous copying of 100,000 A4 size J paper Evaluated. These results are shown in Table 3.

(Bleed)
The obtained semiconductive belt was brought into contact with the OPC photoreceptor for 2 weeks in a high-temperature and high-humidity environment (48 ° C., 90% RH), and image quality evaluation was evaluated using the OPC photoreceptor.
○: There is no problem in the transfer image quality ×: There is a problem in the transfer image quality at the part where the semiconductive belt is in contact (whiteout occurs)

(Evaluation of transfer image quality)
The obtained semiconductive belt was modified from Fuji Xerox Co., Ltd. Docu Color 1255CP and mounted on the image forming apparatus having the configuration shown in FIG. 6 to evaluate the transfer image quality. The OPC photoconductor was used as the photoconductor.

(1) Blur evaluation The occurrence of blur was evaluated according to the following criteria.
○: No blurring or slight blurring, no problem in image quality ×: Bluring, problem in image quality

(2) Holocharacter evaluation The occurrence of holocharacters was evaluated according to the following criteria.
○: Occurrence is slight and there are few image quality problems ×: Image quality problems

(Continuous running; evaluation of contamination)
The following criteria were used to evaluate the occurrence of white spots when a halftone of 30% magenta was copied after continuous copying of 100,000 A4 size J paper.
○: No whiteout occurs ×: There is whiteout and there is a problem in image quality (contamination of the belt surface)

  From the results of Table 3, the semiconductive belts of Examples 12 to 15 of the present invention were free from image quality defects and could stably obtain excellent image quality over a long period of time. On the other hand, in Comparative Examples 8 to 10, there was no occurrence of image quality defects such as blur and holocharacter, but in the continuous paper running test, white image quality defects occurred due to contamination of the belt surface. Further, Comparative Example 8 has a problem that the roughness of the belt surface is smooth and has high adhesion to the photoreceptor, and Comparative Example 10 has a low molecular oil component dispersed in the belt base material. There was a so-called bleed phenomenon of precipitation on the surface.

-Example 16-
<Preparation of intermediate transfer belt>
(Formation of conductive elastic layer)
Granular acetylene black (manufactured by Denki Kagaku Kogyo Co., Ltd .: oil absorption 288 ml / 100 g) with respect to 100 parts of a rubber material (NE40; manufactured by Nippon Synthetic Rubber Co., Ltd.) in which NBR and EPDM are blended at a mass ratio of 4: 6 A rubber composition having a mixing ratio of 10 parts and 22 parts of Asahi Thermal FT (Asahi Carbon Co., Ltd .: oil absorption 28 ml / 100 g and average particle size of 80 μm) was kneaded with two rolls. The obtained kneaded material was formed into a tube shape by a tube cross head extruder. Subsequently, the molded blend rubber material was heated and vulcanized in a vulcanizing can with a pressurized steam at a temperature of 126 ° C. and a pressure of 1.5 kg / cm ² G to form a conductive belt material. The obtained belt material is placed on the outside of a metal tube, and the surface is polished to produce a rubber belt made of an elastic layer having a thickness of 0.5 mm, an inner diameter of 140 mm, a width of 352 mm, and a volume resistivity of 3 × 10 ⁹ Ωcm. did.
The hardness of the elastic belt was 55 degrees in terms of JISA hardness.
All volume resistivity values obtained by reading the current value 30 seconds after applying a voltage of 100 V using a resistance meter (HR probe from Hiresta IP; manufactured by Dia Instruments Co., Ltd.) It is.

(Formation of outermost layer)
The following composition was mixed with a ball mill to prepare a dispersion in which a conductive agent (antimony-doped tin oxide) and a solid lubricant (graphite fluoride) were uniformly dispersed in a fluororesin.
・ Copolymer resin of tetrafluoroethylene and vinyl ether: 100 parts
(Zeffle GK-500: manufactured by Daikin Industries, Ltd.)
・ Isocyanate cross-linking agent (Coronate HL: manufactured by Nippon Polyurethane Co., Ltd.) 2 parts Antimony doped tin oxide (SN-100P: manufactured by Ishihara Sangyo Co., Ltd.) 20 parts graphite fluoride (Cefbon-CMA: Central Glass) 3 parts) The dispersion obtained is dip-coated on the surface of the elastic roller on which the resistance layer is formed, and then heated and dried to a film thickness of 3 μm consisting of a fluororesin film. The outermost layer was formed.
The volume resistivity of the semiconductive belt of Example 16 manufactured as described above is 8 × 10 ⁹ Ωcm, the contact angle of the belt surface is 120 degrees, and the ten-point average surface roughness Rz. Was 3 μm.

<Production of paper transport belt>
Resin composition comprising 100 parts of polyvinylidene fluoride resin (manufactured by Kureha Chemical Industry Co., Ltd .: trade name “# 850”) as a conductive agent and 0.2 part of cesium perfluorooctane sulfonate as an inorganic metal salt Using a single screw extruder, the product was molded into a resinous seamless belt having a thickness of 0.15 mm, a circumferential length of 948 mm, and a width of 352 mm. The volume resistivity of this belt was 2 × 10 ¹⁰ Ωcm. The coefficient of friction was 0.3.

-Example 17-
<Preparation of intermediate transfer belt>
(Formation of conductive elastic layer)
70 parts of epichlorohydrin rubber (manufactured by Nippon Zeon Co., Ltd., Gechron 3105, ethylene oxide content: 38 mol%) and 30 parts of acrylonitrile butadiene rubber (manufactured by Nippon Zeon Co., Ltd., DN202H, content of acrylonitrile): 31%, As an electron conductive agent, 9 parts of granular acetylene black (manufactured by Electrochemical Co., Ltd., DBP oil absorption: 288 ml / 100 g) and Asahi Thermal MT (manufactured by Asahi Carbon Co., Ltd., DBP oil absorption: 35 ml) / 100g) 17 parts together, 1 part of sulfur (Tsurumi Chemical Co., Ltd., 200 mesh) and 1.5 parts of vulcanization accelerator (Ouchi Shinsei Chemical Co., Ltd., Noxera-M) are added, Kneaded with an open roller. The obtained kneaded material was formed into a tube shape by a tube cross head extruder.
Subsequently, the molded blend rubber material was heated and vulcanized in a vulcanizing can with a pressurized steam at a temperature of 126 ° C. and a pressure of 1.5 kg / cm ² G to form a conductive belt material. The obtained belt material is placed on the outside of a metal tube, and the surface is polished to produce a rubber belt made of an elastic layer having a thickness of 0.5 mm, an inner diameter of 140 mm, a width of 352 mm, and a volume resistivity of 2 × 10 ¹⁰ Ωcm. did.
The elastic belt had a JISA hardness of 50 degrees.
All volume resistivity values were obtained by reading the current value 30 seconds after applying a voltage of 100 V using a resistance meter (HR probe from Hiresta IP; manufactured by Mitsubishi Yuka Co., Ltd.). is there.

(Formation of outermost layer)
A charging member was fabricated in the same manner as in Example 16 except that the blending amount of graphite fluoride was changed to 10 parts when forming the outermost layer. The volume resistivity of the semiconductive belt of the semiconductive belt portion of Example 17 obtained in this way is 3 × 10 ¹⁰ Ωcm, and the contact angle of the surface is 125 degrees. The point average surface roughness Rz was 9 μm.

  Note that the same paper transport belt as in Example 16 was used.

-Example 18-
<Production of paper transport belt>
(Formation of outermost layer)
As an outermost layer material, 100 parts of vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Kureha Chemical Industry Co., Ltd .: trade name “# 2300”) as conductive agent, inorganic metal salt, cesium perfluorooctane sulfonate A resinous seamless belt having a thickness of 0.1 mm, a peripheral length of 948 mm, and a width of 352 mm was added. The volume resistivity of the sheet was 5 × 10 ¹⁰ Ωcm. The coefficient of friction was 0.3.

(Base material)
Tetracarboxylic dianhydride in which 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) are combined at a ratio of 1: 1 and 4,4 N-methyl-2-pyrrolidone (NMP) solution of polyamide consisting of '-diaminodiphenyl ether (DDE) (solid content 20%) was dried with oxidized carbon black (SPECIAL BLACK4 (manufactured by Degussa, pH 4.0, volatile content). 14.0%) was added to 15 parts of polyimide resin solid content, and mixed with a ball mill at room temperature for 6 hours.Then, this carbon black-dispersed polyamide solution was added to the inner surface of the cylindrical mold via a dispenser. After applying to 0.5 mm and rotating at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, 250 While rotating at rpm, apply hot air at 60 ° C for 30 minutes from the outside of the mold, heat at 150 ° C for 60 minutes, then cool to room temperature, peel off from the mold, and coat the outside of the iron core The mixture was further heated at 350 ° C. for 1 hour to remove the solvent, remove the dehydrated ring-closing water, and complete the imide conversion reaction, then return to room temperature, peel from the mold, and achieve the desired semiconductivity. The base material of the belt was obtained, the thickness of the base material of this semiconductive belt was 0.08 mm, the volume resistivity was 5 × 10 ¹⁰ Ωcm, and the Young's modulus was 2100 MPa.

Using the outermost layer and the base material, the outermost layer / adhesive layer / base material is pressed against a cylindrical mold and heated at a temperature of 150 ° C. for 60 minutes under a pressure of 5.5 kg / cm ^2. A two-layer belt was formed. As the adhesive layer, a urethane-based adhesive (Nipporan 2301 manufactured by Nippon Polyurethane Co., Ltd.) was used with a thickness of 0.005 mm. The thickness of each layer of this semiconductive belt was 0.1 mm for the outermost layer and 0. It was 08 mm.

  The same intermediate transfer belt as that used in Example 16 was used.

-Comparative Example 11-
<Preparation of intermediate transfer belt>
Polyamide N-methyl-2-pyrrolidone (NMP) solution of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) (Uwanisu S 15%), 15 parts of acetylene black (pH 5.7 manufactured by Denki Kagaku Kogyo Co., Ltd., volatile content: 0.89%) was added to 100 parts of polyimide resin solids, and mixed at room temperature for 6 hours by a ball mill. Next, this carbon black-dispersed polyamide solution is applied to the inner surface of the cylindrical mold to a thickness of 0.5 mm via a dispenser, rotated at 1500 rpm for 15 minutes to form a spread layer having a uniform thickness, and then rotated at 250 rpm. However, after applying hot air of 60 ° C. from the outside of the mold for 30 minutes, heating at 150 ° C. for 60 minutes and then cooling to room temperature, And then the outer surface of the iron core was coated and heated at 400 ° C. for 1 hour to remove the solvent, remove the dehydrated ring-closing water, and complete the imide conversion reaction. The desired semiconductive belt was peeled off, and the thickness of the semiconductive belt was 0.08 mm, the volume resistivity was 2 × 10 ¹⁰ Ωcm, and the Young's modulus was 6000 Mpa. The coefficient of friction was 0.45, the surface contact angle was 90 degrees, and the ten-point average surface roughness Rz was 0.8 μm.

<Evaluation>
The intermediate transfer belt and the sheet conveying belt obtained in Examples 16 to 18 are mounted on the image forming apparatus shown in FIG. 8, and the intermediate transfer belt obtained in Comparative Example 11 is shown in FIG. Attached to an image forming apparatus, the transfer image quality (blur, holocharacter) and embossed paper running performance were evaluated. These results are shown in Table 4.

(Blur evaluation)
The occurrence of blur was evaluated according to the following criteria.
◎: No blurring ○: Bluring is slight and there is no problem in image quality ×: Bluring occurs and there is a problem in image quality

(Holo character evaluation)
The occurrence of holo-characters was evaluated according to the following criteria.
◎: No image quality problem ○: Slight occurrence, few image quality problems ×: Image quality problem

(Embossed paper runnability)
The image quality was evaluated when a halftone of 30% magenta was copied by running an embossed paper with a step of 50 μm, and evaluated according to the following criteria.
◎: Image quality problem in continuous 1000-sheet running test ○: No significant image quality problem in continuous 1000-sheet running test ×: Image quality problem

  From the results shown in Table 4, according to the image forming apparatuses of Examples 16 to 18 of the present invention, there was no image quality defect, and excellent image quality could be stably obtained over a long period of time. On the other hand, Comparative Example 11 had a problem in the runnability of the embossed paper.

It is sectional drawing which shows the structure of the semiconductive belt of this invention. It is a figure which shows the measuring method of volume resistivity. FIG. 3 is a schematic view showing a main part of an image forming apparatus using the semiconductive belt of the present invention as a transfer conveyance belt. FIG. 2 is a schematic view showing a main part of an image forming apparatus using the semiconductive belt of the present invention as an intermediate transfer belt. 1 is a schematic view showing an example of an image forming apparatus using a semiconductive belt of the present invention as an intermediate transfer belt. 1 is a schematic view showing an example of an image forming apparatus using a semiconductive belt of the present invention as an intermediate transfer belt. 1 is a schematic view showing an example of an image forming apparatus using a semiconductive belt of the present invention as an intermediate transfer belt. 1 is a schematic view showing an example of an image forming apparatus using a semiconductive belt of the present invention as an intermediate transfer belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outermost layer 2 Base material 4b Secondary transfer apparatus 5a Transfer conveyance belt (semiconductive belt)
5b Intermediate transfer belt (semiconductive belt)
6a Image carrier 6b Image carrier 7a Recording medium 7b Recording medium 8a Transfer device 8b Primary transfer device 9a Tension roll 9b Tension roll 10 Photosensitive drum (image carrier)
DESCRIPTION OF SYMBOLS 11 Charging device 12 Exposure device 13 Rotary type developing device 13a-13d Developing device 17 Cleaning device 20 Intermediate transfer belt (semiconductive belt)
21-24 Tension roll 25 Primary transfer roll 26 Cleaning roll 30 Secondary transfer roll 40 Recording medium 41 Supply tray 42 Pickup roll 43 Registration roll 44 Conveying belt 45 Fixing device 46 Conveying roll 47 Discharging roll 48 Discharging tray 71 Toner cartridge 72 Fixing Roll 73 Backup roll 74 Tension roll 75 Secondary transfer roll 76 Paper path 77 Paper tray 78 Laser generator (exposure equipment)
79 Photosensitive drum (image carrier)
80 Primary transfer roll 81 Drive roll 82 Intermediate transfer body cleaner 83 Charging roll 84 Photoconductor cleaner 85 Developer 86 Intermediate transfer belt 88 Static elimination roll 101 Photosensitive drum (image carrier)
102 Intermediate transfer belt 103 Bias roll (secondary transfer roll)
104 Paper tray 105 Black developing device 106 Yellow developing device 107 Magenta developing device 108 Cyan developing device 109 Intermediate transfer body cleaner 113 Peeling claw 121 Belt roll 122 Backup roll 123 Belt roll 124 Belt roll 125 Conductive roll (primary transfer roll)
126 Electrode roll 130 Static elimination roll 131 Cleaning blade 141 Recording medium (recording paper)
142 pickup roll 143 feed roll 201 image carrier 203 intermediate transfer belt 205 recording medium 207 primary transfer roll 209 secondary transfer roll 211 tension roll 213 tension roll 215 tension roll 217 tension roll 221 paper transport belt 223 tension roll 225 Stretch roll A ′ first voltage application electrode B ′ second voltage application electrode C ′ cylindrical electrode part D ′ ring electrode part T ′ semiconductive belt

Claims (8)

  A semiconductive belt composed of one or more layers, wherein the outermost layer is made of a thermosetting elastomer composition in which a lubricating filler and a conductive agent are dispersed, and the outermost layer has a surface D hardness of 30 to 30. And a ten-point average surface roughness Rz of the outermost layer is 1.5 μm to 9.0 μm.   A semiconductive belt having an outermost layer and a base material on the inner side thereof, the base material is made of an elastic body, and the outermost layer contains at least a fluororesin and graphite fluoride A semiconductive belt characterized by.   An image forming apparatus for recording a toner image formed on an image bearing member on a recording medium, the transfer conveying belt disposed so as to be in contact with the image bearing member, or disposed so as to be in contact with the image bearing member. An image forming apparatus using the semiconductive belt according to claim 1 or 2 as an intermediate transfer belt.   4. The image forming apparatus according to claim 3, wherein recording is performed on a recording medium having a surface unevenness difference of 40 to 60 [mu] m and a thickness of 100 to 260 [mu] m.   An image forming apparatus for recording a toner image formed on an image carrier on a recording medium, comprising a plurality of the image carriers, the same number of intermediate transfer belts as the image carriers, and one sheet conveying belt. And each intermediate transfer belt is disposed in contact with each image carrier, and the sheet conveying belt is disposed in contact with all the intermediate transfer belts. An image forming apparatus using the semiconductive belt described in 1 above.   6. The image forming apparatus according to claim 5, wherein the recording is performed on a recording medium having a surface unevenness difference of 40 to 60 [mu] m and a thickness of 100 to 260 [mu] m.   A toner image forming step for forming toner images on a plurality of image carriers, and a primary transfer of the toner images onto each intermediate transfer belt disposed so as to be in contact with each image carrier. A transfer process, and a secondary transfer process in which a toner image primarily transferred for each intermediate transfer belt is secondarily transferred onto a recording medium conveyed by a paper conveyance belt disposed so as to be in contact with all the intermediate transfer belts; An image forming method comprising: using the semiconductive belt according to claim 1 or 2 as the intermediate transfer belt, and applying a transfer voltage in the secondary transfer step to the intermediate transfer belt and the recording medium. An image forming method characterized in that control is performed after contact.   The image forming method according to claim 7, wherein the image forming method is used for recording on a recording medium having a surface unevenness difference of 40 to 60 μm and a thickness of 100 to 260 μm.

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