JP6451295B2 - Conductive elastic belt, conductive elastic belt unit, image forming apparatus - Google Patents

Description

  The present invention relates to a conductive elastic belt, a conductive elastic belt unit, and an image forming apparatus.

  For example, Patent Document 1 discloses a nylon coating containing a solvent-soluble nylon, a nylon cross-linking agent, an adhesion improver for the molded product, and an organic solvent on the surface of a molded product of a stretchable material such as rubber or elastomer. A nylon-coated molded product used for a belt or the like on which a film of the forming composition is formed is disclosed.

Further, Patent Document 2 was obtained by a manufacturing method having a drying step of applying a lubricant layer forming coating to an elastic substrate layer to form a coating layer, and drying the coating layer to form a lubricant layer. A semiconductive seamless belt is disclosed.
Patent Document 3 discloses a semiconductive belt having an elastic layer made of semiconductive rubber and a surface layer, the surface layer comprising a resin layer containing polytetrafluoroethylene resin fine powder, A semiconductive belt having a hardness-corresponding peak voltage value measured by the SPM method of −6.35 V or less is disclosed.

Further, Patent Document 4 discloses a seamless belt having a base material composed of a single layer having different properties on the front surface and the back surface due to uneven distribution of additives in the thickness direction.
Patent Document 5 discloses a fixing belt for electrophotography in which a heat-resistant elastic layer and a fluororesin layer are sequentially laminated on the surface of a sheet-like substrate, and the relationship between the strain amount and the pressure in the thickness direction of the surface is disclosed. When the slope of the graph shown is K, K ≧ 2.0 × 10 ⁻¹¹ m / Pa, and when the restoration rate with respect to the pressure in the thickness direction of the surface is R, a fixing belt with R ≧ 60% is obtained. It is disclosed.
Patent Document 6 has an elastic layer and a photosensitive layer laminated on a base layer, and further, between the elastic layer and the photosensitive layer, is larger than the Young's modulus of the elastic layer and smaller than the Young's modulus of the photosensitive layer. An intermediate transfer belt having a buffer layer exhibiting Young's modulus is disclosed.
Patent Document 7 has a surface layer on an elastic layer, and the surface layer contains lubricating particles in an amount of 10% by mass to 80% by mass with respect to the total solid content of the entire surface layer. Particle distribution is in the range of 3.0 ≧ the amount of lubricating particles on the surface layer surface / the amount of lubricating particles inside the surface layer ≧ 0.8 and the surface roughness is in the range of 0.1 μm to 3 μm A transfer body is disclosed.
In Patent Document 8, at least three layers of a base layer, an elastic layer, and a surface layer are sequentially laminated from the inner peripheral surface toward the outer peripheral surface, and the surface layer contains more than 1 part by mass of fluoro rubber with respect to 1 part by mass of the fluororesin. A multilayer belt having a rubber latex and a curing agent in a proportion of 5 parts by weight or less is disclosed.

JP 2001-131477 A JP 2005-284119 A JP 2010-122314 A JP 2002-012681 A Japanese Patent Laid-Open No. 11-174485 JP 2004-29738 A Japanese Patent Laid-Open No. 10-039647 JP 2010-15143 A

  The problem of the present invention is that the conductive elastic belt is formed from a structure having only two layers of a rubber base material and a release layer, or the Martens hardness of the release layer is higher than the Martens hardness of the intermediate layer. The present invention also provides a conductive elastic belt that suppresses the expansion of cracks in the release layer while appropriately suppressing the wear of the release layer as compared with the case where the size of the release layer is small.

  The above problem is solved by the following means.

The invention according to <1>
A conductive rubber substrate;
A protective layer provided on the conductive rubber base material, provided between the release layer, the conductive rubber base material and the release layer, and has a Martens hardness higher than that of the release layer. A protective layer comprising a lower intermediate layer;
A conductive elastic belt having

The invention according to <2>
The Martens hardness of the release layer is at 10 N / mm ² or more 25 N / mm ² or less, the conductive elastic belt according to the Martens hardness of the intermediate layer is less than 5N / mm ² or more 10N / mm ² <1> It is.

The invention according to <3>
The release layer contains a urethane resin and at least one lubricant selected from the group consisting of polytetrafluoroethylene, molybdenum disulfide, graphite, boron nitride, silica, and polyamide powder <1> or It is an electroconductive elastic belt as described in <2> .

The invention according to <4>
The conductive elastic belt according to any one of <1> to <3> , wherein the release layer further contains a reinforcing agent.

The invention according to <5>
The total thickness of the protective layer is 1 μm or more and 15 μm or less, and the ratio of the thickness of the release layer to the intermediate layer (the thickness of the release layer / the thickness of the intermediate layer) is 1/10 or more and 10/1. The conductive elastic belt according to any one of <1> to <4> , which is the following.

The invention according to <6>
The volume resistivity of the conductive elastic belt is from 10 ⁵ Ωcm to 10 ⁸ Ωcm, and the surface resistivity of the conductive elastic belt measured from the release layer surface is from 10 ⁷ Ω / □ to 10 ¹¹ Ω / □. The conductive elastic belt according to any one of <1> to <5> .

The invention according to <7>
<1> to the conductive elastic belt according to any one of <6> ,
A plurality of rolls that span the conductive elastic belt in a tensioned state;
It is a belt unit provided with.

The invention according to <8>
An image forming apparatus comprising the conductive elastic belt according to any one of <1> to <6> .

According to the invention according to <1>, <3>, or <4> , compared to a case where the conductive elastic belt is formed of a structure having only two layers of a rubber base material and a release layer, or Provided is a conductive elastic belt that suppresses the expansion of cracks in the release layer while appropriately suppressing the wear of the release layer as compared with the case where the Martens hardness of the release layer is smaller than the Martens hardness of the intermediate layer. .
According to the invention of claim 2, Martens hardness of the release layer is more than 10 N / mm ² less than 25 N / mm ^2, compared to the case Martens hardness of the intermediate layer is 5N / mm ² less than 10 N / mm ² or more Thus, a conductive elastic belt is provided in which the wear of the release layer is moderately suppressed and the expansion of cracks in the release layer is suppressed.

According to the invention according to <5> , the ratio of the thickness of the release layer to the intermediate layer (the thickness of the release layer / the thickness of the intermediate layer) is larger than that in the case where the ratio exceeds 10/1. There is provided a conductive elastic belt in which expansion of the belt is suppressed.
According to the invention according to <6> , the volume resistivity of the conductive elastic belt is less than 10 ⁵ Ωcm, and the surface resistivity measured from the release layer surface of the conductive elastic belt is less than 10 ⁵ Ω / □. In comparison with the above, a conductive elastic belt in which expansion of cracks in the release layer is suppressed is provided.

According to the invention according to <7> or <8> , the conductive elastic belt is formed of a two-layer structure of a rubber base material and a release layer, or the Martens of the release layer. Compared to the case where a conductive elastic belt whose hardness is lower than the Martens hardness of the intermediate layer is applied, a conductive elastic belt that suppresses the expansion of cracks in the release layer while suppressing the wear of the release layer moderately. A belt unit or an image forming apparatus is provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

<Conductive elastic belt>
The conductive elastic belt according to the present embodiment includes a conductive rubber base material and a protective layer provided on the conductive rubber base material. Further, the protective layer includes a release layer and an intermediate layer, and the intermediate layer is provided between the conductive rubber base material and the release layer. And it forms so that the Martens hardness of this intermediate | middle layer may become lower than the Martens hardness of a mold release layer.

  Since the conductive elastic belt according to the present embodiment has the above-described configuration, expansion of cracks in the release layer is suppressed while appropriately suppressing wear of the release layer. The reason for this is not clear, but is presumed as follows.

  For example, a conductive elastic belt (that is, a conductive elastic belt having no intermediate layer) in which a protective layer made of a release layer is provided on a conductive rubber substrate is used in, for example, an electrophotographic copying machine, an image In some cases, the present invention is applied to a recording medium conveyance belt (hereinafter referred to as a “paper conveyance belt”) that is used in a forming apparatus and conveys a recording medium. When the above-mentioned conductive elastic belt is applied to a paper conveying belt, a crack (hereinafter, “crack” may be referred to as “crack”) occurs in the release layer due to an expansion change due to the environment and repeated bending and rotating motion. Sometimes it was easy. This release layer crack is caused by belt degradation due to ozone deterioration due to the discharge phenomenon at the time of paper conveyance peeling, physical deformation due to the cleaning load of the blade, etc., and changes in the elongation load of the elastic belt due to changes in the usage environment of the image forming apparatus. This is caused by the difficulty of the release layer following the elongation of the material.

  In some cases, the cracks in the release layer are connected to each other due to the stretching action of the elastic belt accompanying the change in the use environment of the image forming apparatus, and the cracks are easily expanded. When the crack is expanded, for example, a cleaning blade that scrapes off deposits adhering to the surface of the paper transport belt can easily enter the paper transport belt, and the crack can be easily expanded. In addition, the end of the cleaning blade may be chipped and the cleaning performance may be reduced. In addition, when the wear resistance of the release layer is low, the cleaning property may deteriorate due to wear of the release layer by the cleaning blade. In addition, since the cleaning blade easily enters the paper transport belt, the crack generated in the release layer is further easily expanded.

  On the other hand, when a release layer having a high hardness is formed so as to suppress the occurrence of cracks, dirt due to toner, paper powder, or the like may be fixed (filming). Therefore, if the wear resistance of the release layer becomes too high by increasing the hardness of the release layer, the cleaning properties of the blade and the like may be lowered.

  As described above, if the wear resistance of the release layer is too low, the release layer is likely to crack due to temperature change or elongation change, and further, the generated crack is more likely to be expanded continuously. As a result, the cleaning property tends to be deteriorated. Further, even if the release layer has too high wear resistance, the cleaning property tends to be lowered. That is, it is considered that the mold release layer is easily suppressed from being deteriorated in cleaning properties because the wear property is moderately suppressed.

In contrast, the conductive elastic belt according to the present embodiment has an intermediate layer and a release layer, and a protective layer formed so that the Martens hardness of the intermediate layer is lower than the Martens hardness of the release layer. Have. In addition, since the intermediate layer having a Martens hardness lower than the Martens hardness of the release layer has a buffering effect on the intermediate layer even when the conductive elastic belt expands due to a change in use environment. The cracks generated in the release layer are suppressed from being connected and expanded.
In addition, since the Martens hardness of the intermediate layer is lower than the Martens hardness of the release layer, that is, the Martens hardness of the release layer is higher than the Martens hardness of the intermediate layer, the release layer has appropriate wear resistance. ing.
As a result, the conductive elastic belt according to the present embodiment is considered to suppress expansion of cracks in the release layer while appropriately suppressing wear of the release layer.
In addition, when it has moderate abrasion, even if image formation is carried out in large quantities (for example, 100,000 sheets), the change in belt driving torque is small, but it does not have moderate abrasion. In some cases, when image formation is performed in a large amount (for example, 100,000 sheets), there may be a phenomenon in which a change in driving torque of the belt due to a decrease in surface properties and a crack becomes large.

As described above, in the conventional conductive elastic belt, cracks generated in the release layer are easily expanded due to an elongation action or the like accompanying a change in use environment. Further, when the release layer does not have an appropriate wear property, a change in the driving torque of the belt may become large. These phenomena are particularly likely to occur when the usage environment changes repeatedly, such as when used in a high temperature and high humidity environment after being used in a low temperature and low humidity environment.
However, the conductive elastic belt according to the present embodiment has the above-described configuration, so that the wear of the release layer is moderated even when the belt bending motion due to the use environment or continuous use is repeated as described above. In addition, the expansion of cracks in the release layer is suppressed.

  In addition, since the conductive elastic belt according to the present embodiment has the intermediate layer, the crack generated in the release layer is suppressed from reaching the conductive rubber base material. Furthermore, by having the intermediate layer, a buffering action is imparted to the conductive elastic belt, and the occurrence of cracks in the release layer caused by the pressing force of the cleaning blade is suppressed.

  In the above, as an example of the conductive elastic belt according to the present embodiment, the case where it is applied to a paper conveyance belt has been described. However, even when applied to another conductive elastic belt such as an intermediate transfer belt, the wear of the release layer While suppressing moderately, expansion of the crack of a mold release layer is suppressed.

  The conductive elastic belt keeps flexibility while following the elasticity of the base material, suppresses paper transportability deterioration due to deterioration of the protective layer, suppresses ozone deterioration resistance of the base material, and maintains a meandering prevention function It is formed to let you.

[Martens hardness]
As described above, in the conductive elastic belt according to this embodiment, the protective layer has a release layer and an intermediate layer, and the Martens hardness of the intermediate layer is higher than the Martens hardness of the release layer. It is formed to be low.

Martens hardness is an index showing the degree of hardness by the load required to make a recess of a certain depth. In the conductive elastic belt according to the present embodiment, the Martens hardness of the intermediate layer and the release layer is measured by the following method.
A belt sample in which an intermediate layer is formed on a rubber base material of a conductive elastic belt to be measured is prepared. That is, a belt base material having the same composition as the rubber base material of the conductive elastic belt to be measured is prepared, and an intermediate layer having the same composition as the intermediate layer of the conductive elastic belt to be measured is provided on the belt base material. A belt sample is prepared. Then, this belt sample is set in a measuring device of a dynamic ultra-micro hardness meter DUH-211 (manufactured by Shimadzu Corporation), and a 90 mm facing pyramid-shaped diamond is used to form a scratch width of 0.01 mm on an intermediate layer. Measure the load when the sag occurs, and measure the Martens hardness of the intermediate layer.
Separately, a conductive elastic belt to be measured is prepared. Then, the Martens hardness of the release layer is measured by the same procedure as the measurement of the Martens hardness of the intermediate layer.
The Martens hardness is measured at a triangular thruster ridge angle of 115 °, with a test force of 0.5 mN, a load speed of 0.03 mN / sec, and a load holding time of 5 seconds.

As described above, the Martens hardness of the intermediate layer is formed to be lower than the Martens hardness of the release layer. The difference between the Martens hardness of the release layer and the Martens hardness of the intermediate layer is preferably 5 N / mm ² or more from the viewpoint of further suppressing crack extension of the release layer while suppressing the wear of the release layer more appropriately. 7 N / mm ² or more is more preferable. Moreover, although it does not specifically limit as an upper limit, For example, it is good that it is 10 N / mm < ² > or less.

The conductive elastic belt according to the present embodiment has a release layer with a Martens hardness of 5 N / mm ² or more and 25 N from the viewpoint of further suppressing the expansion of cracks in the release layer while suppressing the wear of the release layer more appropriately. / Mm ² or less is preferable, and the Martens hardness of the intermediate layer is preferably 5 N / mm ² or more and 15 N / mm ² or less. Further, more preferably Martens hardness of 20 N / mm ² or less 5N / mm ² or more of the release layer, and more preferably Martens hardness of the intermediate layer is less than 5N / mm ² or more 10 N / mm ^2.

(Volume resistivity and surface resistivity)
The conductive elastic belt according to the present embodiment has a volume resistivity of 10 ⁵ Ωcm or more and 10 ⁸ Ωcm or less from the viewpoint of suppressing expansion of cracks in the release layer while appropriately suppressing wear of the release layer. It is preferable that the surface resistivity of the conductive elastic belt measured from the release layer surface side is 10 ⁷ / □ or more and 10 ¹¹ □ or less. Further, when the surface resistivity and the surface resistivity measured from the side of the release layer are in the above range, the occurrence of cracks in the release layer caused by ozone deterioration accompanying peeling discharge between the photoreceptor and the paper is suppressed.

The surface resistivity and volume resistivity of the conductive elastic belt according to the present embodiment are measured in accordance with JIS K 6911 (1995) using a circular electrode (for example, UR probe of Hiresta IP manufactured by Mitsubishi Yuka Co., Ltd.). To do.
The surface resistivity ρs (Ω / □) is calculated by the following formula. Here, in the following formula, d (mm) represents the outer diameter of the cylindrical electrode portion, and D (mm) represents the inner diameter of the ring-shaped electrode portion. The voltage V (V) indicates the applied voltage, and the current I (A) indicates the current that flows when the voltage is applied.
Formula: ρs = π × (D + d) / (D−d) × (V / I)
The surface resistivity is 22 ° C. using a circular electrode (UR probe of Hiresta IP manufactured by Mitsubishi Oil Chemical Co., Ltd .: outer diameter Φ16 mm of the cylindrical electrode portion, inner diameter Φ30 mm of the ring electrode portion, outer diameter Φ40 mm). The current value after application of voltage 500 V for 10 seconds under the / 55% RH environment is calculated.

The volume resistivity is measured using the apparatus used for measuring the surface resistivity. However, the circular electrode is provided with a second voltage application electrode instead of the plate-like insulator at the time of measuring the surface resistivity. Then, the volume resistivity ρv (Ωcm) is calculated by the following formula. Here, in the following formula, t represents the thickness of T of the conductive elastic belt. The voltage V (V) indicates the applied voltage, and the current I (A) indicates the current that flows when the voltage is applied.
Formula ρv = 2.010 × (V / I) × t
The volume resistivity is 22 ° C. using a circular electrode (UR probe of Hiresta IP manufactured by Mitsubishi Oil Chemical Co., Ltd .: outer diameter Φ16 mm of the cylindrical electrode portion, inner diameter Φ30 mm of the ring electrode portion, outer diameter Φ40 mm). The current value after application of voltage 500 V for 10 seconds under the / 55% RH environment is calculated.
Here, 2.011 shown in the above equation is an electrode coefficient for conversion into resistivity, and from the outer diameter d (mm) of the cylindrical electrode portion and the thickness t (cm) of the sample, πd ² / Calculated as 4t. The thickness of the conductive elastic belt is measured using an eddy current film thickness meter CTR-1500E manufactured by Sanko Electronics.

Next, the material of each layer constituting the conductive elastic belt according to this embodiment will be described in detail.

[Conductive rubber substrate]
The conductive rubber base material of the conductive elastic belt according to the present embodiment is made of a conductive rubber material. The conductive rubber substrate includes, for example, a rubber material and a conductive agent, and may include other additives as necessary.
The conductive agent refers to a material having a volume resistivity of less than 10 ⁷ Ωcm, for example.

(Rubber material)
Specific examples of rubber materials include isoprene rubber (IR), chloroprene rubber (CR), epichlorohydrin rubber (CO), butyl rubber (IIR), urethane rubber (U), and silicone rubber (Si, Q). , Fluoro rubber (FKM), styrene-butadiene rubber (SBR), butadiene rubber (BR), nitrile rubber (NBR), hydrogenated NBR (HNBR), ethylene propylene rubber (EPM), epichlorohydrin / ethylene oxide rubber (ECO), epichlorohydrin / ethylene oxide / allyl glycidyl ether rubber (GECO), ethylene / propylene / diene rubber (EPDM), acrylonitrile / butadiene rubber (NBR), natural rubber (NR) and the like. These rubber materials may be used alone or in combination of two or more. In the following description, rubber materials may be indicated by abbreviations shown in parentheses.

  Among these rubber materials, NBR, HNBR, CR, and CO are relatively high in rigidity, have a volume resistivity close to semiconductivity, and have good fluidity in a mold. , ECO and U are preferred. Moreover, CR is preferable in terms of improving flame retardancy, and EPDM is preferable in terms of improving ozone deterioration resistance. Among these rubber materials, CR and NBR are more preferable because they themselves have ionic conductivity. Further, in addition to CR and NBR, it is more preferable to add CO or ECO in that the volume resistivity can be easily adjusted by adding epichlorohydrin rubber-based CO or ECO. A rubber material in which CR, NBR, EPDM, and CO (or ECO) are mixed is particularly preferable from the viewpoints of rubber compatibility, vulcanization balance adjustment, and ozone resistance improvement, and the above viewpoint.

(Conductive agent)
Examples of the conductive agent include an electronic conductive agent and an ionic conductive agent, and either or both of the electronic conductive agent and the ionic conductive agent may be used in combination. From the viewpoint of environmental stability of the electrical characteristics (volume resistivity) of the conductive elastic belt, it is preferable to use an electronic conductive agent and an ionic conductive agent in combination.

Specific examples of the electronic conductive agent include carbon black such as ketjen black and acetylene black; pyrolytic carbon, graphite; various conductive metals or alloys such as aluminum, copper, nickel, and stainless steel; tin oxide, Examples thereof include various conductive metal oxides such as indium oxide, titanium oxide, tin oxide-antimony oxide solid solution, tin oxide-indium oxide solid solution, and the like.
The carbon black specifically includes “Special Black 350”, “Special Black 100”, “Special Black 250”, “Special Black 5”, and “Special Black” manufactured by Orion Engineered Carbons. 4 ”,“ Special Black 4A ”,“ Special Black 550 ”,“ Special Black 6 ”,“ Color Black FW200 ”,“ Color Black FW2 ”,“ Color Black FW2V ”,“ MONARCH1000 ”manufactured by Cabot Corporation "MONARCH1300" manufactured by Cabot Corporation, "MONARCH1400" manufactured by Cabot Corporation, "MOGUL-L", "REGAL400R", and the like.
An electronic conductive agent may be used independently and may be used in combination of 2 or more type.
The content of the electronic conductive agent is, for example, preferably from 1 part by weight to 50 parts by weight, and more preferably from 15 parts by weight to 35 parts by weight with respect to 100 parts by weight of the rubber material.

Specific examples of the ion conductive agent include quaternary ammonium salts (for example, lauryltrimethylammonium, stearyltrimethylammonium, octadodecyltrimethylammonium, dodecyltrimethylammonium, hexadecyltrimethylammonium, modified fatty acid, dimethylethylammonium, etc. Perchlorate, chlorate, borofluoride, sulfate, ethosulphate, halogenated benzyl salt (eg, benzyl bromide, benzyl chloride, etc.); aliphatic sulfonate; higher alcohol Higher alcohol ethylene oxide addition sulfate ester; Higher alcohol phosphate ester salt; Higher alcohol ethylene oxide addition phosphate ester salt; Various betaines; Higher alcohol ethylene oxide; Polyethylene Glycol fatty acid esters; polyhydric alcohol fatty acid esters; various ionic liquids or fluorine antistatic agents; polyaniline, polypyrrole, polysulfone, conductive polymers such as polyacetylene.
The content of the ionic conductive agent is, for example, preferably in the range of 0.1 parts by mass or more and 5.0 parts by mass or less, and 0.5 parts by mass or more and 3.0 parts by mass with respect to 100 parts by mass of the rubber material. The following is more preferable.

Furthermore, in addition to the components listed above, the following rubber compounding raw materials may be used for the rubber material. Examples of the filler include zinc oxide, titanium oxide, magnesium oxide, calcium carbonate, calcium sulfate, clay, talc, and silica. Further, an insulating filler such as zinc oxide (zinc white) may be added to adjust the volume resistivity of the rubber base material. The shape of these fillers is not particularly limited, and those in the form of particles, long fibers and the like are used.
Examples of rubber chemicals include vulcanizing agents, vulcanization accelerators, anti-aging agents, plasticizers, process oils, and the like, and examples of colorants include various pigments.

  The thickness of the conductive rubber base material is, for example, 100 μm or more and 1000 μm or less, more preferably 100 μm or more and 1000 μm or less from the viewpoint of maintaining the strength as a belt, suppressing permanent elongation change, suppressing meandering, etc. Is preferably 300 μm or more and 600 μm or less.

Conductive volume resistivity of the rubber base material, from the viewpoint of obtaining stability of the volume resistivity, etc. to form a protective layer conductive elastic belt, preferably not more than ^{10 7 Ω / cm, 10 6} Ω / More preferable is cm or less. Further, it is preferably 10 ⁴ Ω / cm or more, and more preferably 10 ⁵ Ω / cm or more. The volume resistivity is adjusted by the content of the conductive agent and the rubber material used.

[Protective layer]
The protective layer is formed including an intermediate layer and a release layer. The protective layer may be formed in a two-layer structure of an intermediate layer and a release layer, but if necessary, adhered between the rubber base material and the intermediate layer, or between the intermediate layer and the release layer. A layer may be provided. The intermediate layer may be one layer, but may be formed in a structure of two or more layers as long as it is formed lower than the Martens hardness of the release layer.
In addition, when the protective layer of the conductive elastic belt according to the present embodiment includes an adhesive layer, the Martens hardness of the adhesive layer is preferably lower than the Martens hardness of the release layer. However, since the manufacturing process of the conductive elastic belt becomes complicated, it is preferable not to include an adhesive layer. The adhesive layer is not included in the concept of the intermediate layer.

(Release layer)
The release layer preferably contains a resin from the viewpoint of further suppressing crack expansion of the release layer while suppressing wear of the release layer more appropriately. Moreover, in addition to resin, you may contain any one or both of a lubrication agent and a reinforcing agent as needed.

-Resin-
Examples of the resin include polyurethane resin, polyester resin, polyamide resin, polyacrylic resin, silicone resin, and fluorine-containing resin. These resins may be used alone or in combination of two or more. Among these resins, it is preferable to use a polyurethane resin because it is easy to follow the elongation of the belt base material accompanying a change in use environment.

  In terms of adjusting the Martens hardness, the above resin may be crosslinked with a crosslinking agent. As a crosslinking agent, crosslinking agents, such as an isocyanate compound, a melamine compound, an epoxy compound, an oxazoline compound, a carbodiimide compound, a silane coupling agent, are mentioned, for example.

  In the case of using a polyurethane resin from the above points as the resin used for the release layer, for example, a one-component polyurethane resin in which a main agent and a curing agent are mixed, or two-component curing using a main agent and a curing agent. Type polyurethane resin and the like, and any polyurethane resin may be used.

When using a two-component curable polyurethane resin, examples of the main agent include a resin having a functional group capable of reacting with an isocyanate group as a curing agent. Specific examples include polyols such as acrylic polyols having a hydroxyl group in the molecule, polyester polyols, polyether polyols, polycarbonate polyols, polycaprolactone polyols, and polyolefin polyols. These main agents may be used alone or in combination of two or more.
Examples of the isocyanate compound include aliphatic isocyanates such as hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI); aromatic isocyanates such as tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI); hexamethylene diisocyanate (HDI). ) Isocyanurate trimer; isophorone diisocyanate (IPDI) isocyanurate trimer; mixed isocyanurate trimer of HDI and tolylene diisocyanate (TDI); other isocyanurate trimers, adducts, burettes, etc. Is mentioned. These isocyanate compounds may be used alone or in combination of two or more.

  Here, the polyol and the isocyanate compound are mixed at a blending ratio in which the molar ratio (NCO / OH) of the isocyanate group (NCO group) to the hydroxyl group (OH group) in the polyol is in the range of 1.0 to 1.5. It is preferable. The range of 1.0 to 1.3 is more preferable, and the range of 1.0 to 1.15 is more preferable.

-Lubricant-
The release layer preferably further contains a lubricant from the viewpoint of further improving the release property of the release layer. Examples of the lubricant include polytetrafluoroethylene (PTFE), molybdenum disulfide, graphite, boron nitride, silica, polyamide powder, and the like. Among these, at least one selected from the group consisting of polytetrafluoroethylene (PTFE), molybdenum disulfide, and graphite is preferable. These lubricants may be used alone or in combination of two or more. Among these, it is more preferable to use PTFE from the point which the mold release property of a mold release layer improves more.

  The content of the lubricant contained in the release layer is 100 mass parts of resin contained in the release layer from the viewpoint of further suppressing the expansion of cracks in the release layer while suppressing the wear of the release layer more appropriately. On the other hand, it is preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less. When the content of the lubricant is within this range, the releasability is further enhanced.

-Reinforcing agent-
It is preferable that the release layer further contains a reinforcing agent in terms of further suppressing crack extension of the release layer while suppressing wear of the release layer more appropriately. The reinforcing agent is particles other than the lubricants listed above, and is resin particles or inorganic particles having an effect of reinforcing the release layer.
Specific examples of the reinforcing agent include tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymer (THV), and polyvinylidene fluoride. Resin particles of fluorine-containing compounds such as (PVDF); resin particles other than fluorine resins such as polyimide resin, polyester resin, acrylic resin, polyolefin resin; carbon black, silica, titanium oxide, tin oxide, magnesium oxide, antimony silicon oxide, Inorganic particles such as aluminum oxide can be used. These reinforcing agents may be used alone or in combination of two or more. Among these, it is preferable to use carbon black.

  The content of the reinforcing agent contained in the release layer is based on 100 parts by mass of the resin contained in the reinforcement layer from the viewpoint of further suppressing the expansion of cracks in the release layer while suppressing the abrasion of the release layer more appropriately. It is preferably 5 parts by mass or more and 50 parts by mass or less, and more preferably 10 parts by mass or more and 30 parts by mass or less.

(Middle layer)
The material used for the intermediate layer is not particularly limited as long as it is formed so as to be lower than the Martens hardness of the release layer and is not peeled off from the release layer and the rubber base material. From the viewpoint of further suppressing expansion of cracks in the release layer due to the buffering action of the intermediate layer, the intermediate layer preferably contains a resin. Moreover, in addition to resin, you may contain any one or both of a lubrication agent and a reinforcing agent as needed. However, by controlling the blending ratio, the hardness, interfacial adhesion, flexibility, and the like are adjusted. Therefore, even in the same material system, the blending contents of the additive and lamination by adjusting the ratio may be handled.

-Resin-
For the intermediate layer, the resin exemplified for the resin used for the release layer can be used. Specifically, for example, a polyurethane resin, a polyester resin, a polyamide resin, a polyacrylic resin, a silicone resin, a fluorine-containing resin, or the like can be given. Especially, it is preferable to use the same kind of resin as the resin used for the release layer in that the adhesion to the release layer is improved. As an example, when a polyurethane resin is used for the release layer, it is preferable to use a polyurethane resin for the intermediate layer. However, from the viewpoint of adjusting the Martens hardness of the intermediate layer and the adhesion of the interface, and the buffer action of the intermediate layer, the resin used for the intermediate layer is not crosslinked or the degree of crosslinking is made smaller than that of the release layer. Is preferred.

-Lubricant-
For the intermediate layer, the lubricant exemplified in the lubricant used for the release layer can be used. Specific examples include at least one lubricant selected from the group consisting of polytetrafluoroethylene (PTFE), molybdenum disulfide, and graphite.

-Reinforcing agent-
In the intermediate layer, inorganic particles and resin particle reinforcing agents exemplified in the reinforcing agent used in the release layer can be used. Specifically, for example, tetrafluoroethylene / perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene / hexafluoropropylene / vinylidene fluoride copolymer (THV), and polyvinylidene fluoride (PVDF) are used. Resin particles of fluorine-containing compounds; resin particles other than fluorine resins such as polyimide resin, polyester resin, acrylic resin, polyolefin resin; inorganic such as carbon black, silica, titanium oxide, tin oxide, magnesium oxide, silicon antimony oxide, aluminum oxide Particles.

  When using the above-mentioned lubricant or reinforcing agent for the intermediate layer, the content of the lubricant and reinforcing agent in the intermediate layer is in the release layer in that it is formed to be lower than the Martens hardness of the release layer. The content is preferably less than the content of. Further, the lubricant and the reinforcing agent may not be included in the intermediate layer.

(The ratio of the thickness of the protective layer and the thickness of the intermediate layer and the release layer)
The protective layer has a total thickness of 1 μm or more and 15 μm or less in terms of suppressing the expansion of cracks in the release layer while suppressing wear of the release layer more appropriately. The thickness of the release layer and the intermediate layer The ratio (thickness of the release layer / thickness of the intermediate layer) is preferably 1/10 or more and 10/1 or less. The total thickness is 2 μm or more and 15 μm or less, the ratio of the thickness of the release layer and the intermediate layer is more preferably 1/8 or more and 8/1 or less, and the total thickness is 3 μm or more and 10 μm or less, More preferably, the thickness ratio of the release layer to the intermediate layer is from 1/5 to 5/1.

(Measurement method of thickness of protective layer and thickness of intermediate layer and release layer)
A method for measuring the thickness of the protective layer and the thickness of the intermediate layer and the release layer is performed as follows. For example, a method for calculating the average film thickness by converting the specific gravity of the coating film from the weight difference with respect to the coating amount, or measuring the film thickness of the substrate in advance when coating, A method of measuring the difference from the dry film thickness is used. The film thickness is directly measured using a measuring instrument such as a micrometer, laser roughness meter, eddy current meter, or the like. From the thickness of the intermediate layer obtained by the above measurement method and the thickness of the release layer, the ratio of the thickness of the intermediate layer to the release layer (the thickness of the release layer / the thickness of the intermediate layer) is calculated.

<Method for producing conductive elastic belt>
Next, a method for manufacturing the conductive elastic belt according to the present embodiment will be described.

(Manufacture of conductive rubber substrate)
The method for producing a conductive rubber substrate is not particularly limited as long as a conductive rubber substrate is obtained. For example, a rubber material and a conductive agent are kneaded, and various additives such as a vulcanizing agent and a vulcanization accelerator are added and subjected to extrusion, followed by vulcanization to obtain a conductive rubber base material. . For example, specifically, a material obtained by blending chloroprene rubber (CR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM) and epichlorohydrin rubber (CO) allyl glycidyl ether copolymer (GECO). As an example, it is manufactured as follows.

In order to produce a conductive rubber base material, a conductive agent such as an electronic conductive agent or an ionic conductive agent is mixed and dispersed in CR, NBR, EPDM, and CO, and then these chloroprene rubber and EPDM are added. The mixture is kneaded with a kneader such as a pressure kneader, and a vulcanizing agent, a vulcanization accelerator, etc. are added to perform extrusion.
When extruding the kneaded rubber material described above to obtain a conductive rubber base material, the kneaded rubber is called a vulcanization mandrel and is kneaded in a metal cylinder having the same outer diameter as the belt inner diameter. The material is covered and vulcanized under predetermined conditions (for example, at 170 ° C. for 1 hour). Then, a vulcanized rubber material is placed on the polishing mandrel, the inner and outer peripheral surfaces of the conductive rubber substrate are polished, and the conductive rubber substrate is adjusted by adjusting the thickness and surface smoothness. Is obtained.

(Formation of protective layer)
The method for forming the protective layer is not particularly limited as long as a protective layer having an intermediate layer and a release layer can be formed on the conductive rubber substrate. For example, as an example, an intermediate layer coating solution containing a resin for forming an intermediate layer, a resin containing a lubricant and a reinforcing agent for forming a release layer, and a crosslinking agent for crosslinking the resin And a release layer coating solution. Then, the intermediate layer coating solution is applied onto the conductive rubber substrate by a coating method such as a dip coating method, a spray coating method, or a roll coating method, and then a release layer coating solution is applied. Then, the method of performing the heat-curing process simultaneously with the coating liquid for intermediate | middle layers and the coating liquid for mold release layers adhering on the conductive rubber base material is mentioned. After application of the intermediate layer coating solution, preliminary coating may be performed and the coating film dried and solidified before performing the curing treatment in either one or both of the application of the release layer coating solution.
As an example of another forming method, the intermediate layer coating solution attached on the conductive rubber base material is heated to perform the curing treatment. Next, there is a method in which a release layer coating liquid is applied on the dried intermediate layer and then heated to perform a curing treatment.

  When the intermediate layer and the release layer are formed using a coating liquid as in the example given above, the coating liquid may be either a water-based or solvent-based coating liquid. In view of the working environment, it is preferable to use an aqueous coating solution. Moreover, when it is an aqueous system, any form of an emulsion and a dispersion may be sufficient. The solvent system is a form in which a solid content is dissolved or dispersed in an organic solvent, and the aqueous system is a solid content in water or a mixed solvent of water and a water-miscible organic solvent (for example, alcohol). It indicates a dissolved or dispersed form.

<Other uses>
The conductive elastic belt of the present embodiment is suitably used as a paper conveying belt in an electrophotographic image forming apparatus. The present invention may also be applied to an intermediate transfer belt. In addition, you may apply to other electroconductive elastic belts, such as a cooling belt for cooling the paper after passing a fixing device, and a drive belt.

<Image forming apparatus>
Next, an example of an image forming apparatus to which the conductive elastic belt according to the present embodiment is applied will be described.
The image forming apparatus according to the present embodiment includes, for example, an electrophotographic photosensitive member, a charging unit that charges the surface of the electrophotographic photosensitive member, and an electrostatic latent image that forms an electrostatic latent image on the surface of the charged electrophotographic photosensitive member. Image forming means, developing means for developing the electrostatic latent image formed on the surface of the electrophotographic photosensitive member with a developer containing toner to form a toner image, and transfer means for transferring the toner image to the surface of the recording medium And comprising.

  The image forming apparatus according to the present embodiment includes a fixing unit that fixes a toner image transferred to the surface of a recording medium, and a direct transfer that directly transfers the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium. Type apparatus; intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred onto the surface of the intermediate transfer member, and the toner image transferred onto the surface of the intermediate transfer member is secondarily transferred onto the surface of the recording medium. System, a device equipped with a cleaning means for cleaning the surface of the electrophotographic photoreceptor before charging after transferring the toner image, and irradiating the surface of the image holding body with charge-removing light after transferring the toner image and before charging. A well-known image forming apparatus such as an apparatus provided with static elimination means for eliminating static electricity, an apparatus provided with an electrophotographic photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

In the case of a direct transfer type apparatus, for example, the transfer unit includes a paper transport belt that transports the recording medium, and a transfer member that directly transfers the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium. Applies. The conductive elastic belt according to the present embodiment is applied to the paper transport belt.
In the case of an intermediate transfer type apparatus, for example, the transfer means includes an intermediate transfer member on which a toner image is transferred to the surface and a toner image formed on the surface of the electrophotographic photosensitive member as an intermediate transfer member (intermediate transfer belt). A configuration having primary transfer means for primary transfer to the surface of the recording medium and secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer member to the surface of the recording medium is applied. The conductive elastic belt according to this embodiment is applied to this intermediate transfer belt.

  The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing type (developing type using a liquid developer).

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 1 shows an example in which the conductive elastic belt according to the present embodiment is applied as a paper conveyance belt of a direct transfer type apparatus that directly transfers a toner image formed on the surface of an electrophotographic photosensitive member to a recording medium. 1 schematically shows a configuration of an image forming apparatus.
An image forming apparatus 100 shown in FIG. 1 includes a charging device 11 (an example of a charging unit) that charges the surface of the electrophotographic photosensitive member 10 around the electrophotographic photosensitive member 10 that rotates in the direction of arrow A, and a charged electrophotographic photosensitive member. An exposure device 12 (an example of an electrostatic latent image forming unit) that irradiates the surface of the body 10 with an exposure beam Bm to form an electrostatic latent image, contains toner, and forms an electrostatic latent image on the electrophotographic photosensitive member 10 A developing device 13 (an example of a developing unit) that forms a toner image by developing with toner, and a cleaning device 17 (an example of a cleaning unit) that removes residual toner on the electrophotographic photosensitive member 10 are provided. The cleaning device 17 includes a cleaning blade 17 a and a fibrous member 16 (roll shape) that supplies the lubricant 18 to the surface of the electrophotographic photosensitive member 10.
Further, the image forming apparatus 100 shown in FIG. 1 includes a transfer unit 20, a fixing device 60 that fixes an unfixed toner image transferred to the recording medium P, and a control unit (not shown) that controls the operation of each device (each unit). It has.

The transfer unit 20 (an example of a transfer unit) is formed on the electrophotographic photosensitive member 10 and the pre-transfer charging device 14 that charges the toner image on the electrophotographic photosensitive member 10 prior to electrostatic transfer in the transfer unit 15. The transfer unit 15 includes a paper transport belt 21 that transfers the toner image onto a recording medium P (for example, recording paper (paper)).
In addition, the transfer unit 20 is disposed inside a paper conveyance belt 21 (an example in which a conductive elastic belt is applied) that is stretched between a driving roll 22 and a driven roll 23 with tension, and inside the paper conveyance belt 21. And a transfer roll 24 that is pressed against the electrophotographic photosensitive member 10 via the paper conveying belt 21. Further, a cleaning blade 25 is provided for scraping off deposits on the surface of the paper transport belt 21 after passing through the drive roll 22.
The transfer unit 20 has a function of transferring the toner image on the electrophotographic photosensitive member 10 to the recording medium P conveyed to the transfer unit 15 by the paper conveyance belt 21 rotating in the arrow B direction, and the toner image in the transfer unit 15. Has a function of conveying the recording medium P onto which the toner has been transferred to the fixing device 60.

  Further, the image forming apparatus according to the present embodiment includes a recording medium accommodating unit 50 that accommodates the recording medium P, and a taking-out roll 51 that takes out and conveys the recording medium P accumulated in the recording medium accommodating unit 50 at a predetermined timing. , A transport roll 52 for transporting the recording medium P fed out by the take-out roll 51, a positioning roll 54 for feeding the transported recording medium P to the transfer unit 15 at a predetermined timing, and a recording medium P fed from the positioning roll 54 The guide unit 55 guides the toner image to the transfer unit 15, and the guide unit 56 guides the recording medium P transferred with the toner image transferred by the transfer unit 20 to the fixing device 60.

  As an example to which the conductive elastic belt of the present embodiment is applied, the image forming apparatus provided as a paper conveyance belt has been described as an example. For example, the conductive elastic belt of the present embodiment is used as an intermediate transfer belt. You may apply to the provided image forming apparatus.

<Conductive elastic belt unit>
Next, a conductive elastic belt unit (hereinafter referred to as “belt unit”) to which the conductive elastic belt according to the present embodiment is applied will be described.
The belt unit to which the conductive elastic belt according to the present embodiment is applied includes a conductive elastic belt and a plurality of rolls that are stretched in a tensioned state. For example, the conductive elastic belt is stretched in a state in which tension is applied by a driving roll and a driven roll arranged to face each other.
When the conductive elastic belt according to the present embodiment is applied as, for example, a paper transport belt, the belt unit includes toner on the surface of the photosensitive member (image holding member) in addition to the above-described rolls (driving roller and driven roller). It may be provided with a transfer roll for transferring an image to a recording medium. For example, in the image forming apparatus shown in FIG. 1, the sheet conveying belt 21 that is stretched in a state where tension is applied by the driving roll 22 and the driven roll 23, and disposed inside the sheet conveying belt 21. The unit including the transfer roll 24 that is pressed against the electrophotographic photosensitive member 10 via 21 is an example of a belt unit in the case where the conductive elastic belt according to the present embodiment is applied as a paper transport belt.
Further, for example, when applied as an intermediate transfer belt, in addition to each of the above rolls (drive roll and driven roll), a toner image on the surface of the photoreceptor (image holding body) is applied to an intermediate transfer belt (conductive elastic belt). Another example) a roll for primary transfer and a roll for secondary transfer of the toner image transferred onto the intermediate transfer belt to the recording medium may be disposed.
In addition, the number and position of the roll for passing in a state where tension is applied are not limited, and may be arranged according to the usage mode.

  Examples will be described below, but the present invention is not limited to these examples. In the following description, “part” and “%” are all based on mass unless otherwise specified.

<Example 1>
As a rubber material, 30 parts of chloroprene rubber (CR) (WRT: Showa Denko) and 70 parts of ethylene / propylene / diene rubber (EPDM) (Esprene 505: manufactured by Sumitomo Chemical Co., Ltd.) are kneaded with a pressure kneader to conduct electronic conduction. 30 parts of carbon black (acetylene black: manufactured by Denki Kagaku Kogyo Co., Ltd.) as an agent, 5 parts of zinc oxide (manufactured by Nippon Kagaku Kogyo Co., Ltd.), 5 parts of magnesium oxide (manufactured by Kyowa Chemical Co., Ltd.), sulfur vulcanizing agent ( Sulfax PMC (made by Tsurumi Chemical Co., Ltd.) 1 part, vulcanization accelerator (Noxeller TS, Noxeller DT: both made by Ouchi Shinsei Chemical Co., Ltd.) 1 part each were added and further kneaded with 2 heating rolls .
This kneaded product was extruded into a belt shape (95 mmφ) with a wall thickness of 1.2 mm, and coated on an aluminum drum surface. Thereafter, the mixture was vulcanized with a saturated steam high pressure can at 170 ° C. for 1 hour. Subsequently, it grind | polished so that it might become thickness of 0.45 mm by cylindrical grinding | polishing, and produced the electroconductive rubber base material (rubber hardness 5.5 degree | times).
Next, a protective layer including an intermediate layer and a release layer was formed on the conductive rubber substrate.
On the conductive rubber substrate obtained above, as an intermediate layer coating solution, a one-component aqueous polyurethane resin containing graphite as a coating solution for the intermediate layer (Bondelite L-GP154 (pencil hardness B, containing 5 parts by mass of graphite): Henkel Was applied by spray coating to a thickness of 2 μm (film thickness after drying and solidification), and was dried and solidified at room temperature. Next, a two-component curable aqueous polyurethane resin (bonderite S-FN345 (pencil hardness) containing polytetrafluoroethylene (PTFE) as a release layer coating solution on the dried and solidified coating solution of the intermediate layer coating solution. H, containing 15 parts by weight of PTFE): manufactured by Henkel Co., Ltd.) was applied by spray coating so as to have a thickness of 3.2 μm (film thickness after drying and solidification). Then, together with the intermediate layer dried and solidified on the rubber substrate, it was heated at 120 ° C. for 30 minutes to carry out a curing treatment to obtain a conductive elastic belt.
A tensile test was performed on the conductive elastic belt, and the relationship between tensile elongation and cracks was evaluated. Even when the conductive elastic belt of Example 1 was stretched to a tensile elongation rate of 97%, no deterioration of cracks of G3 or more was observed. The cracks were evaluated according to the crack evaluation criteria described later (the same applies to the following examples and comparative examples).

<Example 2>
As a coating solution for the intermediate layer, a conductive material was used in the same manner as in Example 1 except that a fluororubber emulsion (GL252EA: manufactured by Daikin Industries, Ltd.) was used and applied to a thickness of 3 μm (film thickness after drying and solidification). An elastic belt was obtained.
A tensile test was performed on the conductive elastic belt, and the relationship between tensile elongation and cracks was evaluated. Even when the conductive elastic belt of Example 2 was stretched to 40% as the tensile elongation rate, it retained cracks of G2 or less.

<Example 3>
As the coating solution for the intermediate layer, 100 parts of UV curable polyurethane resin (Aronix M-1310 / Aronix M-110 = 80 parts / 20 parts: polyester polyurethane produced by Toa Gosei Co., Ltd.) and a photopolymerization initiator (Irgacure 184) : Manufactured by BASF Co., Ltd.), and a conductive elastic belt was prepared in the same manner as in Example 1 except that it was applied by roll coating so as to have a thickness of 2 μm (film thickness after drying and solidification). Obtained.

<Example 4>
The rubber material is 20 parts CR, 45 parts EPDM, 30 parts epichlorohydrin rubber (CO), 30 parts carbon black as an electronic conductive agent, and lithium perchlorate (sum) as an ionic conductive agent. A conductive elastic belt was obtained in the same manner as in Example 1 except that 1 part (manufactured by Kojun Pharmaceutical Co., Ltd.) was used.
A tensile test was performed on the conductive elastic belt, and the relationship between tensile elongation and cracks was evaluated. The conductive elastic belt of Example 4 retained cracks of G2 or less even when the tensile elongation rate was extended to 35%.

<Example 5>
Example 1 except that L-GPM210 (manufactured by Henkel) containing molybdenum disulfide was used as the release layer coating solution, and the coating was applied to a thickness of 2.7 μm (film thickness after drying and solidification). Similarly, a conductive elastic belt was obtained.
A tensile test was performed on the conductive elastic belt, and the relationship between tensile elongation and cracks was evaluated. The conductive elastic belt of Example 5 retained cracks of G2 or less even when the tensile elongation rate was extended to 40%.

<Comparative Example 1>
A conductive elastic belt was obtained in the same manner as in Example 1 except that the intermediate layer was not formed and only the release layer coating solution was applied to provide the release layer. This conductive elastic belt is a conductive elastic belt in which only a release layer is formed on a conductive rubber substrate.
A tensile test was performed on the conductive elastic belt, and the relationship between tensile elongation and cracks was evaluated. When the tensile elongation of the conductive elastic belt of Comparative Example 1 was extended to 5%, G3 cracks occurred.

<Comparative Example 2>
As the release layer coating solution, the same procedure as in Comparative Example 1 was conducted except that the release layer was provided by using half the PTFE content of the release layer coating solution of Example 1 (Doctite T820F). A conductive elastic belt was obtained.
A tensile test was performed on the conductive elastic belt, and the relationship between tensile elongation and cracks was evaluated. When the tensile elongation of the conductive elastic belt of Comparative Example 2 was extended to 11%, G3 cracks occurred.

<Evaluation>
The following evaluation was performed about the electroconductive elastic belt obtained by each Example and each comparative example. The results are shown in Table 1.

[Martens hardness]
A conductive elastic belt sample in which the intermediate layer of each example was formed on the rubber base material obtained in each example and each comparative example was prepared, and the Martens hardness of the intermediate layer was measured by the method described above. . Moreover, the electroconductive elastic belt obtained by each Example and each comparative example was prepared, and the Martens hardness of the mold release layer was measured by the method as stated above.

[Thickness of release layer and intermediate layer]
Measurement was performed by the method described above, and the total thickness of the protective layer and the ratio of the thickness of the release layer to the intermediate layer (the thickness of the release layer / the thickness of the intermediate layer) were calculated.

[Evaluation of release layer cracks]
Each conductive elastic belt was mounted as a paper transport belt of D110 (monochrome multifunction machine) manufactured by Fuji Xerox Co., Ltd., and an image was formed using A4 plain paper. Image formation was performed under the following conditions. First, 20,000 sheets of images are formed in a low temperature and low humidity environment (10 ° C., relative humidity 15% RH), and 20,000 sheets of images are formed in a high temperature and high humidity environment (30 ° C., relative humidity 80% RH). Do. Furthermore, 20,000 images were repeatedly formed in a low temperature and low humidity environment (same conditions), 20,000 images in a high temperature and high humidity environment (same conditions), and 20,000 images in a low temperature and low humidity environment (same conditions). A total of 100,000 images were formed. After forming 100,000 images, the release layer surface of the conductive elastic belt was observed to evaluate the crack state.
The evaluation criteria are as follows.
G1: Almost no cracks are observed in the release layer portion G2: Some cracks are observed in the release layer G3: Short cracks are generated in the release layer G4: Some long cracks are generated in the release layer G5: Long cracks occur on the entire surface of the release layer

[Evaluation of Abrasion of Release Layer]
Each conductive elastic belt is mounted as a paper conveyance belt for D110 (monochrome multifunction device) manufactured by Fuji Xerox Co., Ltd., and image formation is performed using A4 plain paper under the same conditions as in the evaluation of cracks in the release layer. It was. The drive torque of the paper conveying belt after forming 80,000 images formed in an environment of high temperature and high humidity was measured, and 100,000 images of images were formed in an environment of low temperature and low humidity. The driving torque of the subsequent paper conveying belt (conductive elastic belt) is measured, and the difference between the two driving torques (“driving torque when 100,000 images are formed” − “when 80,000 images are formed” Driving torque ") was calculated. The driving torque was measured by attaching a torque gauge (manufactured by Fuji Xerox) to the release layer side of the paper conveying belt. When the difference in driving torque is large, wear of the release layer is not appropriately suppressed.
The evaluation criteria are as follows.
G1: 0.2 kgf · cm or more and 0.7 kgf · cm or less G2: 0.8 kgf · cm or more and 1.0 kgf · cm or less (smear generation: uneven image density)
G3: 1.1 kgf · cm or more (blade mekre, defective cleaning)

  In Table 1 below, “No” in the intermediate layer indicates that no intermediate layer is formed, “PU” indicates polyurethane, “PTFE” indicates polytetrafluoroethylene, and “CB” indicates carbon black. “Mo 2 disulfide” represents molybdenum disulfide, respectively.

  From the above results, it can be seen that in this example, expansion of cracks in the release layer is suppressed as compared with the comparative example. Further, in this example, it can be seen that the wear of the release layer is moderately suppressed because the difference in driving torque of the conductive elastic belt is smaller than in the comparative example.

DESCRIPTION OF SYMBOLS 10 Electrophotographic photoreceptor 11 Charging device 12 Exposure device 13 Developing device 14 Pre-transfer charging device 15 Transfer portion 17 Cleaning device 20 Transfer unit 21 Paper transport belt 22 Drive roll 23 Follow roll 24 Transfer roll 50 Recording medium storage portion 51 Take-out roll 52 Conveying roll 54 Positioning roll 55 Guide unit 56 Guide unit 60 Fixing device 100 Image forming apparatus

Claims (13)

A conductive rubber substrate;
A protective layer provided on the conductive rubber base material, provided between the release layer, the conductive rubber base material and the release layer, and has a Martens hardness higher than that of the release layer. A protective layer comprising a lower intermediate layer;
Have a, the Martens hardness of the release layer is at 10 N / mm ² or more 25 N / mm ² or less, the intermediate layer conductive elastic belt Martens hardness of less than 5N / mm ² or more 10 N / mm ² in. The release layer, a urethane resin, polytetrafluoroethylene, molybdenum disulfide, graphite, boron nitride, silica, and at least one lubricant selected from the group consisting of polyamide powder, to claim 1 containing The conductive elastic belt described. The total thickness of the protective layer is 1 μm or more and 15 μm or less, and the ratio of the thickness of the release layer to the intermediate layer (the thickness of the release layer / the thickness of the intermediate layer) is 1/10 or more and 10/1. less conductive elastic belt according to claim 1 or claim 2. A conductive rubber substrate;
A protective layer provided on the conductive rubber base material, provided between the release layer, the conductive rubber base material and the release layer, and has a Martens hardness higher than that of the release layer. A protective layer comprising a lower intermediate layer;
And the release layer contains a urethane resin and at least one lubricant selected from the group consisting of polytetrafluoroethylene, molybdenum disulfide, graphite, boron nitride, silica, and polyamide powder. Conductive elastic belt. The Martens hardness of the release layer is 10 N / mm ² 25 N / mm or more ² The intermediate layer has a Martens hardness of 5 N / mm. ² 10 N / mm or more ² The conductive elastic belt according to claim 4, which is less than 5. The total thickness of the protective layer is 1 μm or more and 15 μm or less, and the ratio of the thickness of the release layer to the intermediate layer (the thickness of the release layer / the thickness of the intermediate layer) is 1/10 or more and 10/1. The conductive elastic belt according to claim 4 or 5, wherein: A conductive rubber substrate;
A protective layer provided on the conductive rubber base material, provided between the release layer, the conductive rubber base material and the release layer, and has a Martens hardness higher than that of the release layer. A protective layer comprising a lower intermediate layer;
  The total thickness of the protective layer is 1 μm or more and 15 μm or less, and the ratio of the thickness of the release layer to the intermediate layer (the thickness of the release layer / the thickness of the intermediate layer) is 1/10. A conductive elastic belt that is 10/1 or less. The Martens hardness of the release layer is 10 N / mm ² 25 N / mm or more ² The intermediate layer has a Martens hardness of 5 N / mm. ² 10 N / mm or more ² The conductive elastic belt according to claim 7, wherein The release layer contains a urethane resin and at least one lubricant selected from the group consisting of polytetrafluoroethylene, molybdenum disulfide, graphite, boron nitride, silica, and polyamide powder. The conductive elastic belt according to claim 8. The conductive elastic belt according to any one of claims 1 to 9 , wherein the release layer further contains a reinforcing agent. The volume resistivity of the conductive elastic belt is from 10 ⁵ Ωcm to 10 ⁸ Ωcm, and the surface resistivity of the conductive elastic belt measured from the release layer surface is from 10 ⁷ Ω / □ to 10 ¹¹ Ω / □. The electroconductive elastic belt according to any one of claims 1 to 10 . The conductive elastic belt according to any one of claims 1 to 11 ,
A plurality of rolls that span the conductive elastic belt in a tensioned state;
Conductive elastic belt unit with An image forming apparatus including the conductive elastic belt according to any one of claims 1 to 11.