JP2015158687A - Laminated belt for image forming apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated endless belt for an image forming apparatus that is excellent in crack resistance and scratch resistance, and is excellent in toner transferability, toner cleanability, and toner filming prevention property, and has high image quality and high durability.SOLUTION: There is provided a laminated endless belt for an image forming apparatus that includes a base material layer, and a coat layer having a thickness of 0.2 μm or more and less than 2.0 μm formed on the base material layer, where the coat layer has 20 to 60 weight% of metallic filler mixed in an active energy ray and/or heat-crosslinked resin, and when the surface electrical resistivity measured at an application voltage of 10 V and 1000 V for 10 seconds are SR(10 V), SR(1000 V), respectively, the following conditions (1) to (3) are satisfied. (1): coat layer SR(10 V)=3×10to 3×10Ω, (2): coat layer SR(10 V)/SR(1000 V)≤10, and (3): base material layer SR(10 V)/coat layer SR(10 V)=0.001 to 500.

Description

  The present invention is excellent in crack resistance, scratch resistance, roller wrinkle characteristics, toner transferability, toner cleaning properties, toner filming prevention properties, excellent high image quality and high durability, and laminated endless for image forming apparatuses. The present invention relates to a belt (endless belt), a manufacturing method thereof, and an image forming apparatus including the laminated endless belt for an image forming apparatus.

  2. Description of the Related Art Conventionally, as an image forming apparatus such as an OA apparatus, an electrophotographic system using a photoconductor and toner and an image forming apparatus using ink have been devised and put on the market. These devices have various electrical resistances such as a photosensitive belt, an intermediate transfer belt, a paper conveyance transfer belt, a transfer separation belt, a charging tube, a developing sleeve, a fixing belt, etc. Controlled endless belts with seams (seamed belts) or without seams (seamless belts) are used.

  For example, an intermediate transfer device used in an electrophotographic system is configured to once form a toner image on an intermediate transfer member and then transfer the toner to paper or the like. An endless belt made of a seamless belt is used for charging and discharging the toner on the surface layer of the intermediate transfer member. The endless belt is set to have different surface electrical resistance and thickness direction electrical resistance (hereinafter referred to as “volume electrical resistance”) for each machine model, and is adjusted to be conductive, semiconductive, or insulative.

  In addition, the paper transport transfer device holds the paper once on the transport transfer body, transfers the toner from the photosensitive member onto the paper held on the transport transfer body, and further removes the paper from the transport transfer body by discharging. It is configured. On the surface of the transport transfer body, an endless belt with or without a seam is used for charging or neutralizing paper. The endless belt is set to have different surface electric resistance and volume electric resistance for each machine model, like the intermediate transfer belt.

  FIG. 1 is a side view of a conventional general intermediate transfer apparatus. In the figure, 1 is a photosensitive drum and 6 is a conductive endless belt. 1 is an electrophotographic process unit including a charging device 2, an exposure optical system 3 using a semiconductor laser as a light source, a developing device 4 containing toner, and a cleaner 5 for removing residual toner. Is arranged. The conductive endless belt 6 is wound around the transport rollers 7, 8, and 9 and moves in the direction of the arrow in synchronization with the photosensitive drum rotating in the direction of the arrow.

  Next, the operation will be described. First, the surface of the photosensitive drum 1 rotating in the direction of arrow A is uniformly charged by the charger 2. Next, an electrostatic latent image corresponding to an image obtained by an image reading device (not shown) is formed on the photosensitive drum 1 by the optical system 3. The electrostatic latent image is developed into a toner image by the developing device 4. This toner image is electrostatically transferred to the conductive endless belt 6 by the electrostatic transfer machine 10 and transferred to the recording paper 11 between the conveying roller 9 and the pressing roller 12.

  By the way, in the case of a conductive endless belt used in an image forming apparatus such as an electrophotographic copying machine or a printer, since it is functionally driven with a high tension and a high voltage for a long time by two or more rolls, it is sufficient. Mechanical durability is required.

  In particular, in the case of an intermediate transfer belt used in an intermediate transfer device or the like, an image is formed with toner on the belt and transferred to paper, so if the belt is loosened, stretched or meandered during driving, the image Due to misalignment, high dimensional accuracy (small circumferential length difference in belt width and uniform thickness), high elastic modulus (high tensile elastic modulus in belt circumferential direction), high bending resistance What is excellent in mechanical properties such as (hard to break) is desired.

  In recent years, electrophotographic image forming apparatuses such as color laser printers and color LED printers have become more competitive with low-cost inkjet image forming apparatuses. Therefore, the electrophotographic image forming apparatus aims at differentiating from the inkjet system by a high-speed printing technique, and is an image forming apparatus that prints at a high speed by a tandem type paper conveyance transfer in which four photoconductors are arranged and an intermediate transfer system. Has been commercialized. For this reason, an endless belt for an image forming apparatus is required to have excellent durability such as further improvement in durability and improvement in wear resistance.

  In addition, there is an increasing demand for higher image quality, especially in the wide range of temperature and humidity environments, high-quality images can be obtained, not only special paper for color printers, but also high-quality paper, recycled paper, It is necessary to obtain high image quality on various papers such as paper and OHP film.

By the way, in the endless belt for an image forming apparatus, since toner adheres, required characteristics for the endless belt change with the progress of the toner.
As a recent approach to high image quality toner, polymerized toner has been commercialized as a spherical toner with a small particle diameter, an average particle diameter of 4 to 6 μm and a small particle diameter variation, and as an external additive 2. Description of the Related Art A large amount of hard spherical or needle-shaped fine particles such as silicon oxide and titanium oxide are used.

  The external additive sometimes damages the surface layer of the endless belt, and the external additive accumulates on the belt starting from the scar, and so-called toner filming covering the belt surface in a film form may occur. When this filming occurs, the glossiness (gloss) of the surface layer decreases, causing malfunctions in various toner concentration sensors incorporated in the apparatus, as well as the smoothness of the surface being impaired and transferred onto the endless belt. In the cleaning mechanism that scrapes off the remaining toner with a rubber blade, a problem of so-called toner cleaning failure that the toner particles remain on the belt without being scraped off occurs.

  In recent years, color printers and copiers, which are becoming more and more miniaturized, are close to the position where the transfer belt and the fixing heat source are arranged. For this reason, the transfer belt is easily exposed to the high heat of the fixing heat source while being stretched around a roller. Therefore, the trace of the roller remains on the surface of the transfer belt, and the image is liable to be adversely affected. Therefore, it is necessary to balance the heat resistance and hardness of the endless belt material.

  In addition, among endless belts used in image forming apparatuses, transfer belts used in intermediate transfer devices and the like are highly demanded of endless belts for high-quality images, and the toner on the photoreceptor is electrostatically charged. Transfers directly onto the transfer belt (primary transfer), combines the color image on the transfer belt, and then transfers the toner onto the paper with electrostatic force (secondary transfer). In addition to the importance of electrical resistance characteristics such as volume electrical resistance characteristics, there is an increasing demand for improved performance in any of the surface physical characteristics, surface chemical characteristics, and wear resistance.

  As described above, the endless belt for an image forming apparatus, particularly the transfer belt, is compatible with both the toner transfer property and the toner non-fixing property for improving the image quality, and the high performance of the endless belt with respect to the change in the external additive material and paper quality of the toner. Various laminated belts coated with various surface layers have been proposed to meet the demand for wear resistance, the requirement for surface smoothness considering the cleaning properties for reducing the particle size of toner, and the like.

For example, Japanese Patent No. 3608806 discloses an intermediate transfer seamless belt provided with a fluorine-based polymer coating layer having a thickness of 1 to 100 μm for the purpose of preventing filming phenomenon in which toner adheres and accumulates on a transfer belt. .
However, there is no description about the surface electrical resistivity of the coating layer, and there has been no study on making the ratio of the electrical resistance between the base layer and the base layer an appropriate value. By coating the surface layer, there is a problem that a difference occurs in electric resistance between when a low voltage is applied and when a high voltage is applied, and image disturbance occurs when there is an environmental change. In addition, since the fluoropolymer is soft, it is easily damaged and has a problem in durability.

Japanese Patent Application Laid-Open Nos. 2007-11117 and 2007-11118 solve a phenomenon called a transfer defect (so-called white spot) of a several millimeter level of a toner image due to peeling discharge when paper is peeled from an intermediate transfer belt. For this reason, an intermediate transfer belt is disclosed in which an aggregate of conductive particles having an average particle size of 0.5 to 25 μm is blended with a silicone resin and spray-coated to a thickness of about 100 μm.
However, even in these publications, no mention is made of the surface electrical resistance value of the coat layer, and no consideration has been given to making the ratio of electrical resistance between the surface layer and the base material layer an appropriate value, There is a problem in that there is a difference in electrical resistance between when a low voltage is applied and when a high voltage is applied, and image disturbance occurs when there is an environmental change. In addition, since the surface layer is soft, there is also a problem in wear resistance, and further, the adhesion between the silicone resin and the base material layer is poor, and as described in the publication, an intermediate layer is used to prevent peeling from the surface layer. There is a problem that it is difficult to control the electric resistance value.

In JP-A-2005-338246, a conductive resin layer using an acrylic resin containing an inorganic substance is formed in the outermost layer, and the innermost layer is composed of a semiconductive resin layer irradiated with heating, light, or electron beam. A seamless semiconductive belt having a layer formed therein is disclosed.
Japanese Patent Application Laid-Open No. 2007-316622 describes an intermediate transfer member provided with a cured (meth) acrylic resin layer as a surface layer.
However, none of these studies have been made on making the ratio of the surface resistivity of the outermost layer (surface layer) and the innermost layer (base layer) to an appropriate value. There is a problem that a difference occurs in electrical resistance and image disturbance occurs when there is an environmental change.

  Japanese Patent Application Laid-Open No. 2008-46463 discloses an intermediate transfer member in which a resin layer having a glass transition temperature of 180 ° C. or less is used for a base material layer and an acrylic resin surface layer is formed as an actinic ray curable resin. However, the electrical resistance value is not described.

  Japanese Patent Application Laid-Open No. 2007-183401 discloses an intermediate transfer belt in which a cured resin film containing conductive particles having a thickness of 0.5 to 3 μm is applied and formed on a base layer. However, since this does not control the electric resistance value of the cured resin film, the surface resistance value is greatly reduced particularly when a high voltage is applied, and there is a problem that image distortion occurs.

Japanese Patent No. 3608806 JP 2007-11117 A JP 2007-11118 A JP 2005-338246 A JP 2007-316622 A JP 2008-46463 A JP 2007-183401 A

  As described above, various types of laminated belts for image forming apparatuses have been proposed in the past, but any of the laminated belts in any document does not take into account the characteristics of the electrical resistance values of the base layer (innermost layer) and the surface layer (outermost layer). Therefore, the electrical resistance value of the laminated belt becomes unstable due to the difference in the electrical resistivity of the surface layer and the electrical resistivity of the base layer and the difference in thickness, and as a result, the surface electrical resistivity of the laminated belt is There has been a problem that it may change greatly depending on the applied voltage and cause image abnormality.

In other words, an endless belt in which a surface layer is simply formed by simply coating a base layer formed by extrusion molding according to a conventional method cannot realize a laminated belt having a small change in surface electrical resistivity due to the magnitude of applied voltage. As a result, a change in surface electrical resistivity causes an image abnormality.
The reason is as follows.

  A semi-conductive endless belt obtained by molding a thermoplastic resin containing a conductive filler or conductive carbon black by an extrusion method is usually extremely microscopic due to the presence of a resin layer called a skin layer on the surface layer. The surface layer portion has a high electric resistance value. This is a characteristic attributed to the polymer resin material having viscoelasticity, and is caused by the difference in shearing force between the surface layer and the intermediate layer (intermediate layer in the belt thickness direction) at the time of extrusion molding. This is because the dispersion state of the conductive filler and the conductive carbon black differs between the surface layer (skin layer) and the intermediate layer due to the difference in shearing force generated between them.

  Due to the presence of this skin layer and the difference in orientation between the surface layer and the intermediate layer (difference in the dispersion state of the conductive filler and conductive carbon black), the electrical resistance when a low voltage is applied to a conventional extruded endless belt There is a problem that the so-called electric resistance value is highly dependent on the applied voltage, such as a high value and a low electric resistance value when a high voltage is applied.

When a surface layer of a thin film by a coating whose surface electrical resistivity is not controlled within a certain range (such a surface layer is referred to as a “coat layer” in the present invention) is applied to such an endless belt, The surface electrical resistivity is a surface electrical resistivity obtained by adding the surface electrical resistivity of the coating layer and the surface electrical resistivity of the endless belt as the base material layer, and the dependency of the surface electrical resistivity on the applied voltage is further increased.
If the surface electrical resistivity is highly dependent on the applied voltage, the surface electrical resistivity is high at low voltage, so that the discharge from the paper is likely to occur, and the toner is scattered when the toner is transferred to the paper. Problems related to toner transfer occur, such as smearing or voids in the center of a solid image.

  Further, even if a base material layer having a small dependency of surface electrical resistivity on the applied voltage is obtained, a coating material having a small surface electrical resistivity on the applied voltage is coated on such a base material layer. Even when the layers are laminated, if the difference between the resistance value of the base material layer and the resistance value of the coat is extremely large, the dependency of the electrical resistance value on the coating layer surface side becomes large, and the above-mentioned problem Will occur.

  This problem tends to be resolved by increasing the thickness of the coat layer, but in order to improve surface scratch resistance, it is necessary to increase the surface hardness of the coat layer, and the coat having a high surface hardness is required. When the material is thickly provided on the surface of the base material layer, in the endless belt that is stretched by a roller and used, the coat layer hits the outer portion, so the distortion becomes larger than the inner layer, and as a result, the coat layer The problem that it becomes easy to generate | occur | produce a crack and it becomes easy to peel from a base material layer generate | occur | produces. Therefore, it is necessary to make the coat layer as thin as possible.

  When the coating layer is thinly formed, the surface resistivity of the substrate layer and the surface electrical resistance of the coating layer are set so that a current flows through the substrate layer even when a high voltage is applied. It is important to set the base layer to have as high a surface electrical resistivity as possible, and to make this difference as much as possible. Not.

  Conventionally, since the selection of the constituent materials of the base material layer and the coat layer has not been optimized, there is a problem of cracking due to insufficient adhesion, and a laminated belt that achieves both wear resistance and crack resistance. Is not obtained. That is, when wear resistance is important, it is conceivable to form a hard coat layer by applying a coating material having a high surface hardness (so-called hard coat material) to the base layer and crosslinking and curing it. Since the active energy rays for curing and the influence of heat are given to the base material layer, the base material layer becomes brittle and a problem arises in crack resistance.

  On the other hand, a soft coating material can be increased in thickness and thus has excellent crack resistance. However, since the coating layer is soft, scratches due to toner external additives are likely to occur, resulting in poor wear resistance.

  Therefore, in the past, as a laminated endless belt in which a coating layer is formed on a base material layer, the surface electrical resistivity is less dependent on the applied voltage, the environmental variation, or the electrical resistance value variation of the transfer roller, paper, etc. On the other hand, there is no endless belt that can stably obtain a high-quality image without causing image abnormality constantly, and further, wear resistance, crack resistance, roller resistance, and The present condition is that the lamination | stacking endless belt excellent also in surface smoothness is not provided.

  The present invention solves the above-mentioned problems, and the object of the present invention is to provide high image quality and high quality with excellent crack resistance and scratch resistance, and excellent toner transferability, toner cleaning properties, and toner filming prevention properties. An object of the present invention is to provide a durable laminated endless belt for an image forming apparatus and an image forming apparatus including the laminated endless belt for an image forming apparatus.

  As a result of intensive investigations to solve the above problems, the present inventors have focused on the surface electrical resistivity characteristics of the coat layer, and can be a laminated endless belt in which the surface electrical resistivity of the coat layer is set within a predetermined range. For example, it is possible to reduce the dependency of the surface electrical resistivity on the applied voltage even in the case of a laminated belt, and thereby it is possible to stably obtain high image quality without being affected by paper peeling discharge or the like. I found it.

  The present invention has been achieved on the basis of such findings and has the following gist.

[1] A laminated endless belt used in an image forming apparatus, comprising at least a base material layer and a coating layer formed on the base material layer and having a thickness of 0.2 μm or more and less than 2.0 μm, The layer is formed by blending a metal filler with active energy rays and / or a thermal crosslinking resin, the content of the metal filler is 20 wt% or more and 60 wt% or less, and measurement was performed at an applied voltage of 10 V for 10 seconds. When the surface electrical resistivity is SR (10 V) and the surface electrical resistivity measured at an applied voltage of 1000 V for 10 seconds is SR (1000 V), the surface electrical resistivity of the coating layer is as follows: A laminated endless belt for an image forming apparatus, characterized in that the surface electrical resistivity of the base material layer and the surface electrical resistivity of the coat layer satisfy the following condition (3):
(1) SR (10V) of coat layer = 3 × 10 ⁸ Ω or more, 3 × 10 ¹³ Ω or less
(2) SR (10V) / SR (1000V) of the coating layer = 10 or less
(3) SR (10V) of base material layer / SR (10V) of coat layer = 0.001 or more, 500 or less

[2] The laminated endless belt for an image forming apparatus according to [1], wherein the coating layer thickness / base material layer thickness ratio is 1/750 or more and 1/100 or less.

[3] The laminated endless belt for an image forming apparatus according to [1] or [2], wherein the average primary particle diameter of the metal filler is 30 nm or less.

[4] The laminated endless belt for an image forming apparatus according to any one of [1] to [3], wherein the metal filler is tin oxide doped with phosphorus.

[5] In any one of [1] to [4], the active energy ray and / or the thermal crosslinking resin is a resin obtained by crosslinking an acrylic monomer and / or an acrylic oligomer. Laminated endless belt.

[6] In any one of [1] to [5], the base material layer is selected from the group consisting of a resin having an ester bond, a polyfluorinated vinylidene, an ethylenetetrafluoroethylene copolymer, a polyamide, and a thermoplastic elastomer. A laminate for an image forming apparatus, characterized in that it is a seamless belt obtained by extrusion molding a molding material obtained by heating and mixing a selected one or more thermoplastic polymer components and a conductive component. Endless belt.

[7] In any one of [1] to [6], the base material layer is formed by blending a conductive component mainly composed of carbon black into a polymer component, and the coat layer mainly contains the metal filler. A conductive component as a component is blended with a polymer component, and the polymerization ratio of the metal filler in the coat layer to the coat layer is greater than the polymerization ratio of carbon black in the substrate layer to the substrate layer. A laminated endless belt for an image forming apparatus.

[8] The image forming apparatus according to any one of [1] to [7], wherein the image forming apparatus is a seamless intermediate transfer belt, conveyance transfer belt, transfer fixing belt, fixing belt, photoconductor belt, or development sleep. Laminated endless belt.

[9] A method for producing a laminated endless belt for an image forming apparatus according to any one of [1] to [8], wherein a coating film is formed by applying a crosslinkable liquid to the surface of the base material layer. A method for producing a laminated endless belt for an image forming apparatus, comprising the step of forming the coating layer by crosslinking and curing the coating film with active energy rays and / or heat after forming.

[10] The image according to [9], wherein the substrate layer is formed by extrusion molding, and the coating layer is formed by spraying the crosslinkable liquid material on the rotating substrate layer. A method for producing a laminated endless belt for a forming apparatus.

[11] The image forming apparatus according to [9] or [10], wherein the base material layer is formed by extrusion molding that satisfies at least one of the following conditions (a) to (c): Method for manufacturing endless belts.
(A) The melt tube take-off speed during extrusion molding is 1.0 m / min or more. (B) The ratio of the thickness of the base material layer / the lip clearance of the extrusion die mold is 0.12 or less. (C) The average of the base material layer. Thickness is 120μm or less

[12] In any one of [9] to [11], the crosslinkable liquid material is applied by spray coating, and a discharge amount of the crosslinkable liquid material at the time of spray coating is 0.1 g / min or more and 10 g / min. The manufacturing method of the lamination | stacking endless belt for image forming apparatuses characterized by the following.

[13] In any one of [9] to [12], the crosslinkable liquid material contains propylene glycol monomethyl ether and / or propylene glycol monoethyl ether as a diluting solvent for the active energy ray and / or the thermal crosslinking resin. A method for producing a laminated endless belt for an image forming apparatus.

[14] Manufactured by the method for producing a laminated endless belt for an image forming apparatus according to any one of [1] to [8] or a laminated endless belt for an image forming apparatus according to any one of [9] to [13]. An image forming apparatus comprising the laminated endless belt for an image forming apparatus.

  According to the present invention, the crack resistance and scratch resistance are excellent, and the toner transfer property, toner non-fixing property and toner cleaning property are all good, especially crack resistance, scratch resistance, toner transfer property and toner cleaning property. It is possible to provide a laminated endless belt for an image forming apparatus that is excellent in quality, can stably obtain a high-quality image with high durability, and an image forming apparatus including the laminated endless belt for an image forming apparatus.

It is a side view of a general intermediate transfer device.

Hereinafter, embodiments of the present invention will be described in detail.
In the present invention,
SR (10V) is the surface electrical resistivity measured at an applied voltage of 10V for 10 seconds.
SR (100V) is the surface electrical resistivity measured at an applied voltage of 1000V for 10 seconds.
In addition,
SR (100V) is the surface electrical resistivity measured at an applied voltage of 100V for 10 seconds.
SR (250 V) is the surface electrical resistivity measured at an applied voltage of 250 V for 10 seconds.
SR (500V), the surface electrical resistivity measured at an applied voltage of 500V for 10 seconds,
Is written.
Further, in the present invention, the “main component” refers to a component that is contained most in the blended material in a material formed by blending a plurality of components.

[Surface electrical resistivity]
The laminated endless belt for an image forming apparatus of the present invention is a semiconductive region where the surface electrical resistivity of the coat layer satisfies the following condition (1), and the applied voltage dependency of the surface electrical resistivity of the coat layer is as follows. It is characterized in that the surface electrical resistivity of the coating layer is smaller than the surface electrical resistivity of the base material layer so as to satisfy the condition (2) and to satisfy the following condition (3).
(1) SR (10V) of coat layer = 3 × 10 ⁸ Ω or more, 3 × 10 ¹³ Ω or less
(2) SR (10V) / SR (1000V) of the coating layer = 10 or less
(3) SR (10V) of base material layer / SR (10V) of coat layer = 0.001 or more, 500 or less

In the present invention, the surface electrical resistivity and the volume electrical resistivity are preferably measured with, for example, a UR probe or UR100 probe of trade name “HIRESTA UP” manufactured by Dia Instruments Co., Ltd., but the surface electrical resistivity is 1 ×. In the case of 10 ¹³ Ω or more, the measurement may be performed by a known method such as connecting a JIS electrode to a trade name “R8340A” manufactured by Advantest Co., Ltd.

The surface electrical resistivity of the base material layer is measured from the surface in the state of the base material layer without the coating layer. In this case, if the base material layer constituting the laminated endless belt is a single layer, the surface electrical resistivity may be measured from the back surface or from the front surface (coating layer forming side). The surface electrical resistivity of the coat layer is the surface electrical resistivity of the single coat layer, for example, an insulating base material, specifically, a base material such as a polyester film. And then cured to form a coat layer, and the surface electrical resistivity can be measured.
The surface electrical resistivity of the laminated endless belt is measured with respect to the surface of the laminated endless belt (coating layer surface) formed by forming a coating layer on the base material layer.

If the SR (10V) of the coat layer is smaller than the lower limit of the above condition (1), when the charged toner is transferred onto the endless belt, the charge disappears before being transferred to the paper. The toner image is disturbed. On the contrary, when SR (10V) of the coating layer is larger than the upper limit of the above condition (1), the toner is charged and it becomes difficult for the toner to be neutralized, and there is a peeling problem when the toner on the endless belt is transferred to paper. Arise.
The preferred SR (10V) range of the coating layer varies depending on the purpose of use of the endless belt, but in the case of a transfer belt, SR (10V) = 1 × 10 ⁹ Ω or more and 1 × 10 ¹³ Ω or less, and a particularly preferred range. SR (10V) = 3 × 10 ⁹ Ω or more and 8 × 10 ¹² Ω or less.

In the above condition (1), the surface electrical resistivity of the coat layer is defined by the surface electrical resistivity at an applied voltage of 10 V. This is a conductive component of the extreme surface layer portion of the outermost surface of the coat layer. It is found that the dispersibility of the toner has the most influence on the image quality of toner transfer, and the dispersibility of the conductive component in the coat layer is related to the surface electrical resistivity measured when a minute voltage of 10 V is applied as the applied voltage. This is due to the knowledge that there is.
That is, it is important to disperse a conductive component that does not cause a micro discharge on the extreme surface of the coat layer in order to prevent missing characters or fine lines from transferring toner or scattering toner.

In addition, although the said condition (1) prescribes | regulates the surface electrical resistivity measured with the applied voltage 10V about the coat layer, the coat layer concerning this invention is the surface in any conditions of the applied voltage 10V-1000V. The electrical resistivity satisfies the above condition (1), that is, not only SR (10 V) but also SR (100 V), SR (250 V), SR (500 V), and SR (1000) are all 3 × 10 ^8. It is preferable to be 3 × 10 ¹³ Ω, particularly 1 × 10 ⁹ to 1 × 10 ¹³ Ω, and particularly 3 × 10 ⁹ to 8 × 10 ¹² Ω.

Further, the condition (2) that defines the upper limit of SR (10 V) / SR (1000 V) of the coat layer is important in that the toner transfer is uniformly performed even with a voltage fluctuation applied by a roller or the like. However, since the surface electrical resistivity when 10 V is applied in particular represents the electrical resistance value of the very surface layer of the endless belt, it is an important characteristic that the effect of preventing the peeling discharge of the paper can be grasped.
The applied voltage of 1000 V is usually based on the fact that the surface electrical resistivity is important because a toner transfer is performed by applying a voltage of at least about 1000 V to the endless belt from the back or surface of the belt. The SR (10 V) / SR (1000 V) of the layer is 10 or less, preferably 8 or less.

  The coat layer according to the present invention is basically a thin film, and the ratio of SR (10 V) of the base material layer / SR (10 V) of the coat layer deviates from the above condition (3) and the surface of the coat layer When the electrical resistivity is higher than that of the base material layer, when the applied voltage is low, the surface electrical resistivity of the coat layer greatly affects, and as the applied voltage increases, the current flows to the base material layer, and the surface of the base material layer The electrical resistivity becomes dominant, and as a result, the surface electrical resistivity greatly changes between when the applied voltage is low and when the applied voltage is high. Since the discharge occurs, a problem that the toner image is disturbed occurs.

  In addition, even if the above condition (3) is satisfied and there is no difference in surface electrical resistivity between the base material layer and the coating layer, the coating with less dependence on the applied voltage of the surface electrical resistivity as in the above condition (2) If it is not a layer, the surface electrical resistivity of the laminated endless belt will reach the base material layer as the applied voltage increases, reaching an unstable state of the surface electrical resistivity of the base material layer, As described above, a problem that the toner image is disturbed occurs.

  In the present invention, a preferable value of SR (10 V) of the base layer / SR (10 V) of the coat layer is 0.01 or more and 200 or less, and particularly preferably 0.1 or more and 100 or less.

  As a characteristic of the surface electrical resistivity of the laminated endless belt of the present invention in which a coating layer is laminated on a base material layer, SR (10 V) / SR (1000 V) is preferably 100 or less, particularly preferably 44 or less. .

Further, the more preferable range of the resistance region of the laminated endless belt of the present invention varies depending on the application. For example, when used as a photoreceptor belt, an applied voltage is applied so that the charge on the outer surface can be released to the inner surface as necessary. The surface resistivity is preferably as low as 1 × 10 ⁷ to 1 × 10 ⁹ Ω at 10V to 1000V, and when used as an intermediate transfer belt, the surface resistivity can be easily charged and transferred 1 × 10 ⁸ to 1 × 10 ¹² Ω is preferable, and when used as a conveyance transfer belt, a high region of 1 × 10 ¹⁰ to 1 × 10 ¹³ Ω which is easily charged and hardly damaged even at a high voltage is preferable.

  In addition, it is preferable that the distribution of the surface electrical resistivity in one laminated endless belt is narrower, and the difference between the maximum value and the minimum value in one preferable surface electrical resistivity region is within two digits ( The maximum value is preferably 100 times or less the minimum value), but 10 times or less is particularly preferable.

The volume resistivity of the laminated endless belt of the present invention is preferably in the range of 1 × 10 ⁶ to 1 × 10 ¹³ Ω · cm (applied voltage 100 V). By satisfying 1), (2), and (3), the volume resistivity is naturally determined.

[Laminated structure]
The laminated endless belt of the present invention only needs to have at least a base layer and a coat layer as a surface layer. There may be an intermediate layer between the base layer and the coat layer, or the adhesion between the two layers. In order to improve the properties, the substrate layer may be subjected to various surface treatments (also referred to as ground treatment) such as primer treatment, plasma treatment, and corona treatment. It is important that at least the surface electrical resistivity characteristics of the coat layer including various treatments and the surface electrical resistivity characteristics of the coat layer and the base material layer satisfy the above conditions (1) to (3).

  In the present invention, the preferred laminated structure is that the coating layer is provided on the base material layer as it is, which is preferable in terms of cost because there are few manufacturing steps. The base layer is provided with a coat layer, a plasma layer is applied to the base layer, and a coat layer is provided on the base layer, or a primer layer is formed on the plasma-treated base material layer. The adhesive force between the material layer and the coating layer is improved, which is preferable in improving crack resistance and preventing the coating layer from peeling off.

  In addition, as a primer process, an acrylic primer is suitable from an adhesive viewpoint. As the plasma processing, a remote type plasma processing apparatus is simple and suitable.

[Coat layer]
In the laminated endless belt of the present invention, the coating layer is formed by blending a crosslinkable liquid material in which a metal filler is blended with an active energy ray and / or a thermal crosslinking resin, and a metal filler as a conductive component is blended, It is preferable that the coating film is formed by coating on the surface of the film and then crosslinking and curing the coating film with active energy rays and / or heat.
Here, the active energy radiation is an electromagnetic wave (gamma ray, X-ray, ultraviolet ray, visible ray, infrared ray, microwave, etc.) or particle beam (electron beam, electron beam, etc.) having a function of generating chemical species capable of initiating a necessary crosslinking reaction. α rays, neutron rays, various atomic rays, etc.), preferably ultraviolet rays or electron rays are used.

  The coating layer according to the present invention is preferably formed by crosslinking and curing a crosslinkable liquid material mainly composed of an acrylic monomer and / or an acrylic oligomer. The crosslinkable liquid material is a conductive material mainly composed of a metal filler. It is preferable to include a component.

<Material of coat layer>
Examples of the crosslinkable liquid for forming the coating layer according to the present invention (liquid that can be cross-linked and cured by applying active energy rays and / or heat) include, for example, melamine, urethane, alkyd, and fluorine. Organic type such as resin type, acrylic radical type, photocation type; inorganic fine particle dispersed acrylic radical type, inorganic fine particle dispersed organic polymer type, inorganic fine particle dispersed organoalkoxysilane type, organic polymer dispersed silica type, acrylic silicone type Organic alkoxy hybrids such as organoalkoxysilanes, organoalkoxysilanes / alkoxyzirconiums, fluorine-containing resins / organoalkoxysilanes, silicates / organic polymers, etc .; alkoxysilanes / alkoxyzirconiums, silicic acids Inorganic type such as salt type; Type, which by blending a metal filler as an electrically conductive component in a so-called hard coating material of the electron beam curing type, these preferable in view of improving the wear resistance.

  These hard coat materials include known ones, among which polyfunctional acrylate oligomers, polyfunctional acrylate monomers, polysiloxanes, and acrylic silicones are preferred.

Examples of the polyfunctional acrylate monomer include dipentaerythritol hexaacrylate, pentaerythritol triacrylate, ditrimethylolpropane tetraacrylate, trimethylolpropane triacrylate, and the like.
In addition, as polyfunctional acrylate oligomers, epoxy acrylates obtained by acrylate-modifying novolak-type and bisphenol-type epoxy resins, urethane acrylates that are acrylate-modified products of urethane compounds obtained by reacting polyisocyanates and polyols, and acrylate-modified polyester resins Examples include polyester acrylate.
These may be used alone or in combination of two or more.

  These acrylic monomers and / or acrylic oligomers are preferably used by blending various additives such as photopolymerization initiators, sensitizers, surfactants and antifouling components, and further diluting solvents.

Examples of the photopolymerization initiator include acetophenone series, benzoin ether series, benzophenone series, and thioxanthone series. Examples of the acetophenone series photopolymerization initiator include diethoxyacetophenone, benzyl methyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2- Hydroxy-2methyl-1-phenylpropan-1-one, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2 -Propyl) ketone, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime and the like.
Examples of the benzoin ether photopolymerization initiator include benzoin, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether.
Examples of the benzophenone photopolymerization initiator include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, and hydroxybenzophenone.
Examples of the thioxanthone photopolymerization initiator include 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, and 2,4-dichlorothioxanthone.

  These photoinitiators may be used individually by 1 type, and may use 2 or more types together. For example, a type that cures with low-wavelength light and a type that cures with long-wavelength light may be used in combination.

  Among these, an acetophenone photopolymerization initiator is preferable because of its high curing rate, and 1-hydroxycyclohexyl phenyl ketone and 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one are particularly preferable.

  The coating layer according to the present invention preferably contains more components than usual from 0.3 to 13% by weight, particularly 3 to 7% by weight, derived from such a photopolymerization initiator. That is, the below-mentioned crosslinkable liquid material forming the coating layer of the present invention preferably contains 0.3 to 13% by weight, particularly 3 to 7% by weight, of the photopolymerization initiator in the solid content. When the content of the photopolymerization initiator is not less than the above lower limit, crosslinking of the crosslinkable liquid material that is a hard coat material is completed in a short time, and when it is not more than the above upper limit, the crack resistance decreases with an increase in the crosslinking density. Is preferable.

As described above, the coating layer according to the present invention needs to be semiconductive, and SR (10 V) needs to be 3 × 10 ^{8 to} 3 × 10 ¹³ Ω. For this reason, it is necessary for the material of the coat layer to include a conductive component for adjusting the coat layer to such semiconductivity.

  As the conductive component, carbon-based fillers such as carbon black, carbon fiber, graphite, and metal fillers are used as conductive fillers. In addition to conductive fillers, polymer type antistatic agents such as polyetheresteramides are used. Agents, ion conductive substances such as quaternary ammonium salts, etc., and these may be used alone or in combination of two or more. It is essential to use a metal filler as the conductive component.

  As metal fillers, powders such as silver, nickel, copper, zinc, aluminum, stainless steel and iron, metal oxide fillers such as zinc oxide, tin oxide, titanium oxide and indium oxide, aluminum doped zinc oxide, antimony doped oxide A particulate conductive metal oxide filler such as tin, phosphorus-doped tin oxide, or tin-doped indium oxide is preferably used. That is, in the present invention, the “metal filler” is not limited to a metal filler made of a metal, but refers to a filler containing a metal element widely. These may be used alone or in combination of two or more.

Among these, the metal filler includes metal oxide fillers such as zinc oxide, tin oxide, indium oxide, and titanium oxide, and conductive metal oxides such as aluminum-doped zinc oxide, antimony-doped tin oxide, phosphorus-doped tin oxide, and tin-doped indium oxide. Filler is preferable, and particularly preferable is a metal oxide filler or conductive metal oxide filler which is a conductive filler close to a semiconductive region with a volume resistance of 5 to 10 ⁶ Ω · cm. Phosphorus-doped tin oxide having a volume resistance of 10 ³ to 10 ⁶ Ω · cm (phosphorus-doped tin oxide) is most preferable because the surface electrical resistivity of the coating layer can be stably controlled to a semiconductive level.

  The metal filler used in the coating layer preferably has an average primary particle size of 30 nm or less, particularly 5 to 25 nm. If the average primary particle size of this metal filler is too large, it is difficult to obtain uniformity of surface electrical resistivity under low voltage, and even if the average primary particle size of the metal filler is too small, the metal filler tends to aggregate, Since it is difficult to obtain uniformity in electrical resistivity, it is preferably within the above range.

  Here, the average primary particle diameter of the metal filler means that the ultrathin section having a thickness of 100 nm cut in the cross-sectional direction of the coat layer is observed with a transmission electron microscope at 500,000 times or 1,000,000 times. This is the average value of 20 particle diameters measured. The same applies to the average primary particle diameter of the filler as an additional component described later.

  It is important that the amount of such a metal filler in the coating layer is 20% by weight or more and 60% by weight or less. If the amount of the metal filler is less than this range, the dispersion state of the conductive component becomes rough, the electrical resistivity tends to vary, the surface electrical resistivity at 10 V applied voltage becomes high, and the electrode and end level The electrical resistance at the contact portion is greatly affected by the temperature and humidity environment, and when the image forming apparatus is mounted as a seamless belt, an image abnormality may occur depending on the temperature and humidity environment. In addition, if the amount of the metal filler is too much within this range, the rigidity of the laminated endless belt will increase, and the durability of the coat layer will be impaired, or when a coating material (crosslinkable liquid) is applied when forming the coat layer This is not preferable because the discharge uniformity is impaired, and the surface electrical resistivity at 10 V applied voltage becomes too low, and the charged toner is electrostatically deposited on the transfer belt and then transferred to paper. However, it cannot continue to adhere to the belt, causing a problem that causes image abnormality.

In addition, although the compounding quantity of the metal filler of a coat layer is determined so that the above-mentioned conditions (1)-(3) may be satisfy | filled within the said range, the content rate of the carbon black contained in the base material layer mentioned later ( It is preferable that the content ratio of the metal filler contained in the coat layer (weight ratio: this ratio is “X ₂ ”) is larger than the weight ratio: “X ₁ ”. In particular, X ₂ is preferably 1.2 to 8 times, more preferably 1.5 to 5 times X ₁ . X ₂ can be prevented that the electric charges of the toner charged in the coating layer surface is lost by moving to the substrate layer by more than X _1, preferred. However, X ₂ / X ₁ has a lower limit as described above in that it is necessary to appropriately move the charge of the charged toner to the base material layer.

  The coating layer according to the present invention may contain a conductive component other than the metal filler as a conductive component, but the main component of the conductive component is preferably a metal filler, preferably a conductive component. The metal filler is preferably 50% by weight or more, particularly 80% by weight or more, and the conductive component is preferably only the metal filler.

  In addition, when the coat layer concerning this invention contains electroconductive components other than a metal filler, the content should just satisfy said conditions (1)-(3), and there is no restriction | limiting in particular.

  In addition, the coating layer may contain an additional component in order to keep the surface of the coating layer moderately slippery and maintain low friction characteristics in order to maintain the cleanability of the surface. As the filler used as the target component, silicone fine particles, PTFE (polytetrafluoroethylene) fine particles, amorphous silica fine particles, and the like having an average primary particle diameter of 5 nm to 1000 nm are preferable. Among these, amorphous silica fine particles having an average primary particle diameter of 5 nm or more and 100 nm or less are preferable because they can impart lubricity without impairing the appearance. Among the amorphous silica fine particles, those having an acrylic group on the surface thereof are preferable because they have a strong bonding force between the particles and are excellent in sustainability of toner cleaning properties.

  The blending amount of the filler for imparting lubricity to the surface of the coat layer is 0.5 to 10% by weight in the coat layer, that is, based on the solid content of the crosslinkable liquid, particularly 1. It is preferable to set it as 0 to 8.0 weight%. When this ratio is equal to or higher than the lower limit, it is possible to impart lubricity to the cleaning blade, and when it is equal to or lower than the upper limit, deterioration of crack resistance can be prevented.

The crosslinkable liquid for forming the coating layer preferably contains a dilute solvent of active energy rays and / or a heat crosslinkable resin, and various organic solvents can be used as the dilute solvent. In order to increase the adhesion rate of the solid content of the crosslinkable liquid material on the base material layer in the case of spray coating, the dispersion point of the metal filler in the conductive liquid material, Is preferably composed mainly of an ether solvent such as propylene glycol monomethyl ether having a boiling point of 121 ° C. and propylene glycol monoethyl ether having a boiling point of 132 ° C., because the same effect can be obtained by widening the evaporation temperature range of the solvent. It is more preferable to use a mixed solvent of these. Further, methyl ethyl ketone having a boiling point of 80 ° C., methyl isobutyl ketone having a boiling point of 118 ° C., boiling point of 1 The solvent having a boiling point different cyclohexane of 6 ° C. may be blended. A preferred dilution solvent is a solvent in which two or more solvents having a boiling point of 100 ° C. or higher are mixed.
When propylene glycol monomethyl ether and propylene glycol monoethyl ether are used in combination as a diluent solvent, the use ratio thereof is propylene glycol monomethyl ether: propylene glycol monoethyl ether = 1: 0.5 to 5, particularly 1: 1. It is preferable to set to ~ 3.

  The preferred blending amount of the solid content and the dilution solvent in the crosslinkable liquid for forming the coating layer is 0.5 to 5 parts by weight with respect to 1 part by weight of the solid content, preferably 1 part by weight of the solid content. The dilution solvent is 1 to 4 parts by weight.

As hard coat materials for forming these coat layers, the amount of conductive component containing metal filler and the amount of dilution solvent are adjusted while adding various solvents and acrylic oligomers and / or acrylic monomers to commercial products as appropriate. May be used.
Examples of commercially available coating materials include “Opstar” and “Desolite” manufactured by JSR, “Defenser FH800ME” manufactured by DIC, “Ray Queen RQ-5001” manufactured by Mitsubishi Rayon, and “Toray Dow Corning” AY42-150 ”,“ X-12-2400 ”manufactured by Shin-Etsu Silicone Co., Ltd.,“ beam set ”manufactured by Arakawa Chemical Industries, Ltd., and the like.

<Application method>
The coating layer according to the present invention is preferably crosslinked by heating and / or irradiation with active energy rays after forming a coating film by applying the crosslinkable liquid (hard coat material) as described above onto the base material layer. It is formed by curing.

  As a method of applying the above-mentioned crosslinkable liquid material (hard coat material) to the base material layer, a dipping coating method, a spray coating method, a ring coating method, a roll coating method, and other blade coaters, knife coaters, die coaters, Although a method using a known coating apparatus such as a gravure coater can be adopted, a dipping coating method or a spray coating method is preferable, and a spray coating method is particularly preferable. It is preferable to discharge at 0.1 g / min or more and 10 g / min or less because a coat layer having a smooth surface can be obtained.

  When the discharge amount of the crosslinkable liquid material is too large, the impact when the crosslinkable liquid material adheres to the base material layer becomes strong, and when the thin film coat layer is formed, the crosslinkable liquid material does not adhere. State so-called pinholes or surface irregularities occur. On the other hand, if the discharge amount of the crosslinkable liquid material is too small, the crosslinkable liquid material will dry before reaching the base material layer, and the crosslinkable liquid material will not level on the surface of the base material layer. Pinholes and surface irregularities may occur. In any case, the pinholes and irregularities are formed on the surface of the coat layer in this way, so that the electric resistance value of the coat layer becomes unstable, and the coat satisfies the above conditions (1) to (3). It becomes difficult to obtain a layer.

  Particularly preferable discharge amount of the crosslinkable liquid is 1 g / min or more and 8 g / min or less, and most preferable is 2 g / min or more and 7 g / min or less. Even a thin film having a coating layer thickness of less than 2 μm is preferable because an endless belt having good surface smoothness, few bubbles, and uniform electric resistivity distribution can be obtained.

  In the present invention, the coating layer is preferably formed by a molding method different from the molding method of the base material layer. In particular, the base material layer is formed by extrusion, and the coating layer is used for forming the coating layer while rotating the base material layer. When the crosslinkable liquid material is applied by spray coating, the orientation direction of the conductive component in each layer is different, that is, in the extrusion molding of the base material layer, the conductive component is oriented in the endrel belt width direction. The spray coating of the coating layer is preferable because the conductive component is oriented in the circumferential direction of the endless belt, and defects in electrical resistance in a minute region within the surface of the obtained laminated endless belt are less likely to appear on the image.

  In addition, as a method of moving the base material when applying the crosslinkable liquid material, the base material layer is stretched by two or more rollers, the base material layer is moved by rotation of the roller, and the crosslinkability is further formed thereon. A method of spray coating a liquid material, or covering a cylindrical support with a substrate layer, and spraying the crosslinkable liquid while moving the substrate layer by rotationally driving the cylindrical support. A method of coating is preferred.

<Crosslinking curing>
As described above, the cross-linking and curing of the coating film formed by applying the cross-linkable liquid material to the base material layer is performed by active energy rays and / or heating.

  Prior to crosslinking and curing, drying may be performed for the purpose of removing the solvent of the coating film. In this case, the heating and drying conditions are preferably 50 to 180 ° C. and about 10 seconds to 15 minutes.

(UV)
When performing cross-linking curing with ultraviolet rays, a known ultraviolet irradiation device can be used. For example, a high-cure lamp or a low-pressure mercury lamp by a mercury lamp method or a metal halide lamp method can be used, and ultraviolet rays having a relative energy peak in a wavelength range of 200 nm to 500 nm are preferably used.
In addition, as the reflector plate method, known ones such as an aluminum mirror method, a cold mirror method, a metal cold mirror method, a cold filter method, a water-cooled jacket method, a double mirror method, etc. can be used. The cold mirror method, the metal cold mirror method, and the cold filter method are preferable because they can prevent the coating film and the substrate from being abnormally heated when irradiated with ultraviolet rays.
The total irradiation energy of ultraviolet radiation, 100 mJ / cm ² or more, preferably 1500 mJ / cm ² or less, particularly if 300~1300mJ / cm ^2, preferably for the coating material is sufficiently crosslinked.

(Electron beam)
When performing cross-linking curing with an electron beam, a known electron beam irradiation apparatus can be used. For example, an electron beam irradiation apparatus having the ability to irradiate with an electron beam irradiation dose of 50 kGy or more and 1500 kGy or less is preferably used.

(Infrared)
When performing cross-linking curing with infrared rays, a known infrared irradiation device can be used. For example, a near infrared irradiation device having a wavelength of 0.75 μm to 4 μm, a far infrared irradiation device having a wavelength of 4 μm to 25 μm, and a super far infrared irradiation device having a wavelength of 25 μm to 1000 μm are preferably used.

(Heat rays)
When performing cross-linking curing by heat, a method of heating at 50 ° C. or higher and 180 ° C. or lower using a known heater, oven or the like can be used.
In addition to the purpose of thermal crosslinking, heating means the purpose of promoting the removal of the solvent, and further the resistance to the roller resistance by promoting the crystallinity of the base material layer or densifying the non-crystalline part. The purpose of improving the characteristics is included and is important in the present invention.
The heating temperature and time are preferably 60 ° C. or higher and 150 ° C. or lower, and the heating time is 15 seconds or longer and 30 minutes or shorter, preferably 30 seconds or longer and 15 minutes or shorter.

  In addition, it is preferable to use heat generated during irradiation with ultraviolet rays, electron beams, and infrared rays because the crosslinking proceeds in a short time and there is no need to increase the number of manufacturing steps.

[Base material layer]
<Material of base material layer>
In the laminated endless belt of the present invention, the constituent material of the base material layer satisfies the above-mentioned condition (3), and realizes a base material layer satisfying suitable physical properties and characteristics of the base material layer and the laminated endless belt described later. There is no particular limitation as long as it can be used, but the main component is a thermoplastic polymer component composed of a thermoplastic resin and / or a thermoplastic elastomer, preferably a conductive component, and further includes an antioxidant. It is preferable.

(Thermoplastic polymer component)
The thermoplastic resin may be a thermoplastic crystalline resin or a thermoplastic amorphous resin, polypropylene, polyethylene (high density, medium density, low density, linear low density), propylene ethylene block Or random copolymer, rubber or latex component, such as ethylene / propylene copolymer rubber, styrene / butadiene rubber, styrene / butadiene / styrene block copolymer or hydrogenated derivatives thereof, polybutadiene, polyisobutylene, polyamide (PA), Polyamideimide (PAI), polyimide (PI), polyacetal (POM), polyarylate (Par), polycarbonate (PC), polyalkylene terephthalate (PAT), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene Nonaphthalate (PEN), Polybutylene naphthalate (PBN), Polytrimethylene terephthalate (PTT), Polymethyl methacrylate (PMMA), Polyphenylene oxide (PPE), Polyethersulfone (PES), Polymethylpentene (TPX), Polyoxybenzylene (POB), liquid crystalline polyester, polysulfone (PSF), polyphenylene sulfide (PPS), polybisamide triazole, polyaminobismaleimide, polyetherimide (PEI), polyetheretherketone (PEEK), acrylic, polyfluoride Vinylidene fluoride (PVDF), polyfluorinated vinyl, chlorotrifluoroethylene, ethylenetetrafluoroethylene copolymer (ETFE), hexafluoropropylene, perfluoroalkyl Examples include vinyl ether copolymers, acrylic acid alkyl ester copolymers, polyester ester copolymers, polyether ester copolymers, polyether amide copolymers, polyurethane copolymers, and the like. Two or more kinds may be used as a mixture.

  Among these, polycarbonate (PC), polyalkylene terephthalate (PAT), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN) polyamide (PA) polyphenylene sulfide ( PPS), polyamideimide (PAI), polyimide (PI), ethylenetetrafluoroethylene copolymer (ETFE), polyfluorinated vinylidene (PVDF), polyester ester copolymer, and polyether ester copolymer are preferable, and PBT is particularly preferable. Polyester ester copolymers, polyether ester copolymers, ETFE, and PVDF are particularly preferred because they have a high crystallization rate, so there is little change in crystallinity due to molding conditions and the crystallinity is stable. That's right.

  As the molecular weight of the thermoplastic resin, a resin having a general molecular weight such as a weight average molecular weight of 10,000 to 100,000 can be used. If there is a demand for high mechanical properties such as tensile elongation at break, the high molecular weight Are preferred. Specifically, it is preferably 20,000 or more, more preferably 25,000 or more, and particularly preferably 30,000 or more.

  On the other hand, as a preferable thermoplastic elastomer used in the present invention, thermoplastic elastomers such as polyester, polyamide, polyether, polyolefin, polyurethane, and vinyl chloride can be used.

  The feature of the thermoplastic elastomer is that the crack resistance of the base material layer can be greatly enhanced and flexibility can be imparted.

  When alloying a thermoplastic elastomer with a thermoplastic resin, use a thermoplastic elastomer with a high affinity with the thermoplastic resin, such as having a common functional group with the thermoplastic resin. This is preferable because the alloy dispersibility is improved, the crack resistance is remarkably improved and the tensile elastic modulus can be adjusted, and excellent surface smoothness and dispersibility of conductive components such as carbon black can be obtained.

  Accordingly, when a polyester such as polybutylene terephthalate or polyethylene terephthalate and / or polycarbonate is used as the thermoplastic resin, it is preferable to use a polyester-based or polyether-based thermoplastic elastomer. In addition, it is preferable to combine a polyamide-based thermoplastic elastomer with an amide-based thermoplastic resin such as nylon.

  The polyester elastomer block is a polyester polyether block copolymer using an aromatic polyester as a hard component, an aliphatic polyether as a soft component, an aromatic polyester as a hard component, and an aliphatic polyester as a soft component. Copolymers can be used.

  Specific examples of thermoplastic elastomers other than polyesters used in the present invention include those based on polystyrene, such as styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-ethylene-butylene-styrene copolymer, styrene- There are ethylene-propylene-styrene copolymers, etc., and in the case of polyvinyl chloride, there are cross-linked (three-dimensional) vinyl chloride-linear vinyl chloride polymers, etc., and as olefins, there are polyethylene-EPDM copolymer, polypropylene-EPDM copolymer, polyethylene- There are EPM copolymer polypropylene-EPM copolymer, etc., and polyester type is PBT (1,4-butadienediol-terephthalic acid condensate) -PTMEGT (polytetramethyleneglycol) -Terephthalic acid condensate) copolymer, and the like, and examples of the polyamide system include nylon oligomer-dicarboxylic acid-polyether oligomer as a basic skeleton. Examples of the nylon oligomer include nylon 6 and nylon 66. Nylon 610, nylon 612, nylon 11, nylon 12 and the like. As the polyether oligomer, for example, polyether glycol, polypropylene glycol, polytetramethylene glycol and the like can be used. Examples of the urethane system include a polyurethane-polycarbonate polyol copolymer, a polyurethane-polyether polyol copolymer, a polyurethane-polycaprolactone polyester copolymer, and a polyurethane-adibate polyester copolymer.

  One of these may be used alone, or two or more thereof may be used as a mixture.

In particular, when a resin having an ester bond in the side chain, polyamide, or thermoplastic elastomer is used as the thermoplastic polymer component, the formed base material layer has excellent crack resistance and the polymer has a polar group. Is preferable because of excellent adhesion to the coating layer.
In addition, when using polyfluorinated vinylidene, ethylenetetrafluoroethylene copolymer, polypropylene, the adhesion between the base material layer and the coating layer is slightly inferior, but the base material layer has an appropriate Young's modulus and It is preferable because of excellent crack resistance.

(Weight ratio of thermoplastic resin to thermoplastic elastomer)
As the thermoplastic polymer component, one or more thermoplastic resins may be used, one or more thermoplastic elastomers may be used, or a mixture of these may be used. Among the thermoplastic polymer components used for the molding material of the base material layer of the endless belt of the present invention, the alloy material of a thermoplastic resin and a thermoplastic elastomer is most preferable.

In this alloy material, the weight ratio of the thermoplastic resin and the thermoplastic elastomer is not particularly limited. However, among thermoplastic resins, crystalline resins are generally excellent in chemical resistance and flex resistance, and amorphous resins are excellent in molding dimensional stability. Therefore, the thermoplastic resin alloy ratio (crystalline The ratio of the resin and the amorphous resin) and the ratio of the thermoplastic resin and the thermoplastic elastomer are preferably set. In particular, the weight ratio of the thermoplastic resin / thermoplastic elastomer is in the range of 99/1 to 30/70. It is preferable that it is in the range of 95/5 to 50/50, more preferably in the range of 90/10 to 55/45.
In particular, since the crystalline component of the thermoplastic resin is resistant to a solvent contained in a coating material for forming a coating layer described later, a material mainly composed of a crystalline thermoplastic resin is preferable.

(Difference in viscosity between thermoplastic resin and thermoplastic elastomer)
When a thermoplastic resin and a thermoplastic elastomer are used as the thermoplastic polymer component, if the viscosity difference between the two materials is too large, good dispersion cannot be obtained even if the production conditions are adjusted, and uniform dispersion cannot be achieved. Therefore, it is preferable that the viscosity difference is small. Specifically, the ratio of the thermoplastic resin and the thermoplastic elastomer measured by MFR under the same conditions is preferably within a range of about 1/20 to 20/1, and should be within a range of 1/10 to 10/1. More preferred.

  In addition, it is preferable to select the conditions close | similar to the processing temperature of a thermoplastic resin composition as measurement temperature conditions based on JISK-7210 as a measuring method of MFR. For example, when PBT and a polyester-based elastomer are selected, it is preferable to set a processing temperature of 240 ° C. as the measurement temperature and compare the viscosity difference between the two materials. Moreover, it can measure suitably by selecting 2.16 kg, for example as a load.

(Melting point of thermoplastic polymer component)
In the present invention, it is preferable to use a thermoplastic polymer component constituting the base material layer having a melting point of 130 ° C. or higher and 260 ° C. or lower according to the following DSC measurement.
DSC (Differential Scanning Calorimetry) measurement: SSC-5200 (trade name) manufactured by Seiko Denshi Kogyo Co., Ltd. was used, the sample was heated to 400 ° C. at a heating rate of 20 ° C./min, and the melting peak temperature was measured by DSC. Melting point.

  If the melting point of the thermoplastic polymer component is too low, the heat resistance of the resulting base material layer is deteriorated, and not only the traces of the rollers are easily made but also the creep property is deteriorated, which is not preferable. On the other hand, if the melting point of the thermoplastic polymer component is too high, the molding temperature at the time of heat-kneading and heat-extrusion is too high, and the surface appearance of the resulting base material layer may be rough due to volatilization of the additive component. The melting point of the thermoplastic polymer component is more preferably 180 ° C. or higher and 250 ° C. or lower, more preferably 200 ° C. or higher and 240 ° C. or lower.

<Conductive component>
Desired conductivity can be obtained by blending the base material layer with a necessary amount of a substance that exhibits conductivity, such as a conductive filler, an antistatic agent, or an ionic conductive substance.

  The conductive component contained in the base material layer is not particularly limited as long as it satisfies the performance required for the application, and various types can be used. Specifically, as the conductive filler, carbon black Metal fillers such as carbon fillers such as carbon fiber and graphite, metal conductive fillers and metal oxide conductive fillers are used. An antistatic agent or an ion conductive substance such as a quaternary ammonium salt may be used, and these may be used in combination.

The selection of the conductive component used for the base material layer of the laminated endless belt in the present invention takes into account the mechanical properties, electrical properties, dimensional properties, and chemical properties of the resulting base material layer, and the environmental dependence due to temperature and humidity. Although it is necessary to consider the cost, it is necessary to satisfy at least the above-mentioned condition (3). From this point, the conductive component is a conductive material mainly composed of a carbon black powder product or a granular product. It is preferable that it is an antistatic agent or a high molecular polymer type antistatic agent.
Of course, carbon black may be the main component, and non-conductive fillers such as antistatic agents may be used as secondary components, or a composite with a conductive metal filler may be used.

  As the conductive component of the base material layer, in particular, it is possible to form minute irregularities on the surface of the base material layer in order to enhance the adhesion with the coat layer, and it is preferable that the surface energy is high. It is preferable to use carbon black as a main component, in particular, 50% by weight or more of the conductive component is carbon black, and it is particularly preferable to use only carbon black as the conductive component.

The blending amount of the conductive component varies depending on the type of the conductive component used. For example, in the case of carbon black, it is preferably 0.1 to 30 parts by weight with respect to 100 parts by weight of the thermoplastic polymer component. If it is less than this range, conductivity will not be manifested, the dispersion state of carbon black will be coarse and the electrical resistivity will be easily dispersed, and the contact resistance will be greatly influenced by the environment. When mounted as a belt, an image abnormality may occur depending on the environment. On the other hand, if the amount is more than this range, the rigidity of the base material layer becomes too large, and the durability is deteriorated or the moldability is impaired.
As described above, the amount of carbon black blended in the base material layer is preferably less than the blend amount of the metal filler blended in the coat layer with respect to the polymer component.

In the present invention, as the carbon black, for the following reasons, in particular DBP oil absorption of 50~300cm ³ / 100g, a specific surface area 35~500m ² / g, volatile content 0-20%, meeting the average primary particle size 20~50nm It is preferable to use carbon black.

(About DBP oil absorption of carbon black)
The larger the DBP oil absorption of carbon black, the easier it is for carbon to form a chain-like chain (carbon structure), and the advantage that carbon aggregates are less likely to be generated. Although there is a cost advantage, on the other hand, there is a problem that the carbon chain is broken due to various shearing forces applied to the resin mixed with carbon black in the process of compounding to molding, and the electric resistivity tends to vary and is not stable. .
On the other hand, if the DBP oil absorption amount of carbon black is too small, it is difficult to form a carbon chain, so that the necessary addition amount for manifesting conductivity is excessively increased and the bending resistance of the material is impaired.
Therefore, DBP oil absorption of the preferred carbon black is 50~300cm ³ / 100g.

(Carbon black particle size and specific surface area)
The larger the specific surface area of carbon black is, the more the conductivity is exhibited with a small addition amount, which is advantageous in terms of mechanical strength (crack resistance), but the conductivity tends to change rapidly depending on the carbon addition amount. Therefore, in order to control to the semiconductive region, a blending accuracy within ± 0.05% is required, and it is difficult to make the resistance variation of the endless belt uniform within ± 1 order. In addition, since carbon black with a large specific surface area generally has a small particle size, when dispersed in a resin, the carbon black particles are likely to be fooled. Electricity concentrates on the surface, and partial dielectric breakdown is likely to occur. In addition, if the specific surface area of carbon black is too small (carbon particles are too large), it is difficult to form carbon aggregates, so the appearance of the molded product is smooth, but the electrical conductivity is easily affected by the contact between the carbon particles. Since the resistivity tends to vary, it is important to select an optimized carbon particle size.
From such points, the average primary particle size of the preferred carbon black is 20 to 50 nm, and the specific surface area is 35 to 500 m ² / g.

(About the volatile matter of carbon black)
The greater the volatile content of carbon black, the better the dispersibility due to its surface characteristics, but it is disadvantageous in molding because it generates gas during heating and kneading. Conversely, the smaller the volatile content of carbon black, the less the gas is generated during heating and kneading, so the moldability is good, but the dispersibility tends to deteriorate. Therefore, the preferable volatile content of carbon black is 0 to 20%.

  There are no particular restrictions on the type of carbon black as long as it satisfies the DBP oil absorption, specific surface area, volatile content, and average primary particle size, and two types of carbon black can be used. It may be above.

  For example, as the type of carbon black, acetylene black, furnace black, channel black, and the like can be suitably used. Among them, acetylene black that has few impurities called ash such as potassium, calcium, sodium, etc., and hardly causes poor appearance, is particularly preferable. It can be used suitably. In addition, carbon black that has been subjected to a known post-treatment process such as resin-coated carbon black, heat-treated carbon black, or graphitized carbon black can be used as long as the object of the present invention is not impaired. .

  Furthermore, carbon black treated with a coupling agent such as silane, aluminate, titanate, and zirconate may be used for the purpose of improving dispersibility and suppressing gas generation.

  Among conductive components other than carbon black, conductive fillers such as silver, nickel, copper, zinc, aluminum, stainless steel, iron powder, aluminum doped zinc oxide, antimony doped tin oxide, phosphorus doped tin oxide, tin doped oxidation A so-called conductive metal oxide filler such as indium having a granular, fibrous or flaky shape is preferably used.

  Among these conductive fillers, aluminum-doped zinc oxide, antimony-doped tin oxide, phosphorus-doped tin oxide, tin-doped indium oxide, so-called conductive metal oxide fillers are preferable, and those having an average particle diameter of 5 μm or less are formed. It is preferable because the surface smoothness of the base material layer can be maintained.

  Nonionic, anionic, cationic and amphoteric antistatic agents are used as the non-filler conductive component. From the viewpoint of heat resistance, the order of anionic, nonionic, amphoteric and cationic is used. Is preferable.

  As the polymer type antistatic agent, polyether ester amide type, ethylene oxide-epichlorohydrin type, polyether ester type are used as nonionic type, polystyrene sulfonic acid type, cationic type as anion type, A quaternary ammonium base-containing acrylate polymer type and the like are preferable. Among them, a polyether ester amide type and a polyether ester type are preferable because they have excellent heat resistance and can reduce decomposition of the thermoplastic polymer component.

<Additive ingredients; optional ingredients>
In the base material layer of the laminated endless belt of the present invention, arbitrary blending components can be blended according to various purposes.

  Specifically, irgafos 168, irganox 1010, antioxidants such as phosphorus antioxidants, heat stabilizers, various plasticizers, light stabilizers, ultraviolet absorbers, neutralizers, lubricants, antifogging agents, anti Various additives such as a blocking agent, a slip agent, a crosslinking agent, a crosslinking aid, a colorant, a flame retardant, a dispersant, and a wax can be added.

In particular, it is preferable to add a Si compound as an additional component to the base material layer because the durability is dramatically improved. In particular, when irradiating active energy rays for crosslinking and curing of the coating layer, the base material layer is affected by the active energy rays at least, so the Si compound is used as a material to maintain crack resistance. It is preferable to mix in.
Preferred examples of the Si compound include silicone rubber, silicone resin (silicone fine particles), silicone oil, and silane compound. Particularly preferred are silicone oil and silane compound (for example, silane coupling agent).

In addition, as a compounding method of the Si compound, it is blended with a thermoplastic polymer component, and is supplied at a time or separately from the hopper inlet of the kneader and heated and kneaded, or only the Si compound is thermoplastic polymer component, carbon black, etc. In addition to this, another feed method for feeding into a kneader may be used, but the present invention is not limited thereto.
Also, carbon black, Si compound, and thermoplastic polymer component are obtained by heat-adding Si compound to carbon black in advance and coating the Si compound on the surface of carbon black, followed by heat mixing using a thermoplastic polymer component and a kneader. It is possible to draw out the interaction with.
In this case, it is preferable to use a silicone oil or a silane compound (for example, a silane coupling agent) as the Si compound, and the amount used is preferably about 0.1 to 10% by weight with respect to the carbon black.

  Furthermore, the constituent material of the base material layer contains compounding materials such as various thermoplastic resins, various elastomers, thermosetting resins, and fillers as the second and third components within the range that does not significantly impair the effects of the present invention. can do.

<Heat kneading method>
There is no particular limitation on the means for heating and kneading the above-mentioned thermoplastic polymer component and conductive component prior to the formation of the base material layer, and a known technique can be used. For example, if a thermoplastic polymer component (thermoplastic resin and / or thermoplastic elastomer), a conductive component, and other additive components blended as necessary are heated and kneaded to form a resin composition, uniaxial extrusion A machine, a twin-screw kneading extruder, a Banbury mixer, a roll, a Brabender, a plastograph, a kneader, or the like can be used.

  In particular, a method in which a thermoplastic polymer component, a conductive component, and other additive components blended as necessary are mixed by, for example, a twin-screw kneading extruder, pelletized, and then molded into an endless belt shape is preferable. Used.

<Molding method>
In the present invention, the method for forming the base material layer is not particularly limited, and known methods such as a continuous melt extrusion method, an injection molding method, a blow molding method, an inflation molding method, a centrifugal molding method, and a rubber extrusion method. However, a particularly preferred method is a continuous melt extrusion method. In particular, an extrusion molding method in which a molten tube extruded from an annular die is drawn while being cooled or cooled and solidified is preferable, and a downward extrusion type internal cooling mandrel method or a vacuum sizing method capable of controlling the inner diameter of the tube with high accuracy is particularly preferable. In particular, the internal cooling mandrel method is most preferable as a method for forming a belt for an image forming apparatus because a seamless belt-like base material layer can be easily obtained. In this case, the annular die is preferably provided with a plurality of temperature adjusting mechanisms in the circumferential direction. The melting tube is preferably cooled by bringing a mold whose temperature is adjusted in the range of 30 to 150 ° C. into contact with the inside or the outside, and in this way, the melting tube is taken up while maintaining the cylindrical shape. It is preferable.

  Also, after producing a film with a crease once by the inflation molding method, it may be an endless belt-like base material layer in a state in which the crease disappears in the post-processing, and once the belt-like sheet is processed, it is connected. It is good also as a base material layer with a seam.

  As a method for forming a base material layer, an extrusion method is advantageous in terms of cost, but it is generally difficult to produce a base material layer having a good dependency of electric resistance on applied voltage. However, it is preferable because the dependence of the electrical resistance value on the applied voltage can be reduced by selecting the type of the thermoplastic polymer component and the conductive component to be used or by setting the molding conditions as described below.

  In particular, (a) the endless tube is continuously taken out after cooling the molten tube at the time of extrusion molding, and the take-up speed is taken at a high speed of 1.0 m / min or more, and thereby the conductive component is spread over the entire thickness direction. Highly oriented, or (b) Extrude the molding material in which the conductive component is dispersed with extremely low orientation by setting the thickness of the base material layer to 0.12 or less with respect to the lip clearance of the die mold. Or (c) If the base layer is a thin base layer having a thickness of 120 μm or less so that the difference in orientation between the surface layer and the center is reduced, a base layer having a small dependence of the electrical resistance on the applied voltage can be easily obtained. It is also preferable because it can be produced at low cost, and the conductive component is deposited on the surface of the molded base material layer, so that the surface of the base material layer is slightly roughened and the adhesion of the coat layer is increased.

  These molding conditions of (a), (b), and (c) may satisfy one of them. Preferably, the surface electrical resistance is further increased by adopting a combination of two or three. Since the base material layer with small dependence of the rate on the applied voltage is obtained, it is preferable.

  In particular, in the molding conditions of (c), the preferable thickness of the base material layer is 100 μm or less, and more preferably 90 μm or less. The minimum of the thickness of a base material layer is 60 micrometers, and when it is thinner than this, since the intensity | strength of a base material layer becomes insufficient, it is unpreferable.

  In the molding condition (b), a more preferable ratio of the thickness of the base material layer / the lip clearance of the extrusion die is 0.10 or less. The lower limit of this ratio is 0.03, and if it is smaller than this, an appropriate shearing force is not applied to the base material layer at the time of extrusion molding, the surface roughness becomes too large, and even if a coating layer is applied thereon, it can be obtained. Since the surface smoothness of the laminated endless belt is inferior, it is not preferable.

  In the molding condition (a), the preferable take-up speed of the molten tube at the time of extrusion molding is 1.2 m / min or more, and the upper limit is 4 m / min or less. When this upper limit is exceeded, there is a problem that the surface electrical resistivity becomes too high as a result of the shear stress applied to the molding material becoming too large during extrusion molding.

<Heat treatment>
The base material layer formed as described above may be subjected to a heat treatment prior to the formation of the coat layer, thereby making it possible to obtain a base material layer with improved physical properties, in particular, bending resistance, Improvements in tensile modulus and roller resistance are observed.

  In this case, although the heat treatment conditions depend on the thermoplastic polymer component to be used, it is usually from 50 to 100 ° C., preferably from 60 to 90 ° C., from 15 minutes to 5 hours, preferably from about 1 hour to 3 hours.

  The heat treatment of the base material layer may be performed by applying heat while driving the endless belt-like base material layer on two or more rollers, or by attaching the base material layer to a cylindrical mold. You can go. Furthermore, the base material layer may be heat-treated in a cylindrical state as it is.

[Physical properties and characteristics of laminated endless belt]
The preferred physical properties and characteristics of the laminated endless belt of the present invention are listed below.

<Thickness>
(Coat layer thickness)
The thickness of the coat layer of the laminated endless belt of the present invention is 0.2 μm or more and less than 2.0 μm. If the thickness of the coat layer is within this range, the surface electrical resistivity of the laminated endless belt is dominated by the electrical resistivity of the base material layer, and the control of the electrical resistivity of the base material layer is already technical. Therefore, the surface electrical resistivity of the laminated endless belt provided with the coat layer is determined by the base material layer, and therefore, the surface electrical resistance value can be easily controlled, which is preferable.

  If the thickness of the coat layer is less than 0.2 μm, the coat layer may be peeled off due to slight scratches and the substrate layer may come out on the surface, which is not preferable because of image defects. In addition, dielectric breakdown due to energization may occur, which is not preferable. Furthermore, the surface electrical resistivity varies greatly with the applied voltage, changes in the paper type and toner charge amount, and the electrical resistance value due to the temperature and humidity of the peripheral parts of the laminated endless belt in the image forming apparatus such as the transfer roller and charging roller. With respect to this change, the electric field strength to the toner on the laminated endless belt tends to be insufficient or excessive, and an image abnormality occurs, which is not preferable.

  When the thickness of the coat layer is 2 μm or more, the distortion due to deformation of the laminated endless belt during roller stretching is the largest in the coated layer that is the outermost layer of the laminated endless belt, so that cracks are more likely to occur from the surface of the coat layer. In addition to problems, the surface electrical resistivity of the laminated endless belt is unfavorable because the surface electrical resistivity of the coat layer is more dominant and it becomes difficult to control the surface electrical resistivity of the laminated endless belt.

  The thickness of the coat layer is preferably greater than 0.3 μm and less than 1.8 μm, and more preferably greater than 0.4 μm and less than 1.5 μm, in view of crack resistance and surface electrical resistivity of the laminated endless belt. From the viewpoint of control, it is also preferable because the dependency of the laminated endless belt on applied voltage can be reduced.

(Base material layer thickness)
The thickness of the base material layer of the laminated endless belt of the present invention is related to the elastic modulus of the base material layer (here, the elastic modulus is the “tensile elastic modulus” described later). If it is 2000 MPa or more, it is preferably 60 μm or more and 160 μm or less, and if the elastic modulus is lower than 2000 MPa, it is preferably 80 μm or more and 180 μm or less. Particularly noteworthy points are that if the thickness is too thick, the thickness deviation increases, so the peripheral speed of the belt changes and image displacement may occur, and if the thickness is thick, the surface layer in the base material layer This is not preferable because the orientation difference in the central portion (central portion in the thickness direction) becomes too large, the difference in dispersion of the conductive filler and the like is large, and the difference in electrical resistance value becomes large. A preferable thickness of the base material layer is 80 to 140 μm, and particularly preferably 90 to 125 μm or less.
However, as the above-described extrusion molding condition (c), the thickness of the base material layer is preferably 120 μm or less, particularly preferably 100 μm or less.

(Thickness ratio between coat layer and substrate layer)
The difference (ratio) between the thickness of the coat layer and the thickness of the substrate layer of the laminated endless belt of the present invention is preferably 1/750 or more and 1/100 or less in terms of the thickness of the coat layer / the thickness of the substrate layer. In the present invention, since the coat layer is basically harder than the base layer, it is preferable that the coat layer is thin and the base layer is thick, but the surface electrical resistance of the coat layer is emphasized while focusing on the wear resistance of the coat layer. The thickness ratio at which the rate and the surface electrical resistivity of the substrate layer interfere moderately is preferably 1/750 or more and 1/100 or less.
If the base material layer is too thick from this ratio, the influence of the electrical resistance value of the base material layer on the coat layer is large, and it becomes difficult to adjust the electrical resistance value. On the other hand, if the coat layer is too thick, the electrical resistance value of the coat layer becomes dominant as the electrical resistance value of the laminated endless belt, so that it is difficult to adjust the electrical resistance value. A more preferable thickness ratio is 1/500 or more and 1/70 or less, and particularly preferably 1/300 or more and 1/50 or less.

<Friction coefficient>
(Coating layer friction coefficient)
The coefficient of friction of the coat layer of the laminated endless belt of the present invention (this value is the coefficient of friction of the laminated endless belt) is preferably 0.05 or more and 0.4 or less. When the coefficient of friction of the coat layer is larger than 0.4, the cleaning effect by the cleaning blade is deteriorated, stick slip occurs between the blade and the belt, and toner and ink slip through. When the friction coefficient of the coat layer is smaller than 0.05, slip is generated when the toner image on the photosensitive member is transferred to the laminated endless belt, and the toner image is disturbed. The friction coefficient of the coat layer is more preferably 0.1 to 0.35.

(Friction coefficient of base material layer)
The friction coefficient of the base material layer of the laminated endless belt of the present invention is preferably as large as possible. In particular, when driven while being stretched by a roller, the endless belt may slip between the roller, and therefore the friction coefficient is preferably 0.2 or more, particularly preferably inside the base material layer. Is 0.3 or more. The upper limit of the friction coefficient of the base material layer is usually 0.6 or less.

  In addition, a friction coefficient is measured by the method shown by the term of the below-mentioned Example.

<Tensile modulus>
(Tensile modulus of base material layer)
The tensile elastic modulus of the base material layer of the laminated endless belt of the present invention is preferably 300 MPa or more and 4500 MPa or less. If the tensile modulus of the base material layer is low, the difference from the elastic modulus of the coating layer becomes too large, so that peeling at the interface between the base material layer and the coating layer occurs due to expansion and contraction when the laminated endless belt is stretched with a roller. Since it becomes easy to generate | occur | produce, it is not preferable. Further, for example, when used in an image forming apparatus as an intermediate transfer belt, a slight elongation may occur due to the tension, and problems such as color misregistration may occur. On the other hand, if the tensile modulus is too high, a motor load is applied when driving the laminated endless belt.Therefore, it is necessary to reduce the thickness setting, and once dust enters between the roller and the belt, If scratches or the like due to friction enter, cracks are likely to occur and there is a problem in reliability. Further, in order to improve the transfer efficiency of the toner in the primary transfer, it is necessary to have a tensile elastic modulus that does not allow the belt to stretch and a tensile elastic modulus that does not cause the endless belt to become hard. The range of the more preferable tensile elastic modulus of the base material layer is 800 MPa or more and 3500 MPa or less, particularly 1000 MPa or more and 3000 MPa or less.

(Tensile elastic modulus of laminated endless belt)
For the same reason as above, the tensile elastic modulus of the laminated endless belt is preferably 800 MPa or more and 5000 MPa or less, more preferably 1000 to 3500 MPa, and particularly preferably 1300 to 3200 MPa.

<Surface roughness (Ra)>
(Surface roughness of substrate layer (Ra))
The surface roughness (Ra) of the base material layer of the laminated endless belt of the present invention is preferably 0.02 μm or more and 0.5 μm or less. When the surface roughness (Ra) of the base material layer is less than 0.02 μm, the area of the lamination interface is reduced during lamination with the coat layer, which may cause a problem in adhesive strength, which is not preferable. However, in that case, it is possible to adopt a known means for increasing the adhesive force by primer treatment, plasma treatment, or the like.
In addition, if the surface roughness (Ra) of the base material layer exceeds 0.5 μm, the laminated endless belt obtained by forming the coating layer is not preferable because the surface roughness of the base material layer is affected. It is particularly preferable that the surface roughness (Ra) of the base layer is 0.02 μm or more and 0.15 μm or less, particularly 0.03 μm or more and 0.12 μm or less.

(Surface roughness of laminated endless belt (Ra))
The surface roughness (Ra) of the laminated endless belt of the present invention after forming the coating layer on the base material layer is preferably 0.02 μm or more and 0.3 μm or less. In particular, if the coating material does not contain an antifouling component, the surface roughness (Ra) is preferably 0.02 μm or more and 0.1 μm or less. Since it is a coefficient of friction, blade cleaning is facilitated, so that the allowable range is widened. The surface roughness (Ra) of the laminated endless belt is particularly preferably 0.02 μm or more and 0.08 μm or less.

<Contact angle with water>
(Contact angle of substrate layer with water)
The contact angle with water of the base material layer of the laminated endless belt of the present invention is preferably small, and is preferably 95 ° or less from the viewpoint of increasing the adhesive strength of the coat layer. The contact angle of the base material layer with water is particularly preferably 80 ° or less, and particularly preferably 75 ° or less.

(Contact angle of coat layer with water)
The contact angle with the water of the coat layer of the laminated endless belt of the present invention (the contact angle with the water of the coat layer is the contact angle with the water of the laminated endless belt) is preferably larger than that of the base material layer. If it is 80 ° or more, it is preferable from the viewpoint of improving the toner non-sticking property, and if it is 90 ° or more, both the cleaning property and the toner fixing property are preferred because there are no problems.
Incidentally, the upper limit of the contact angle of the coat layer with water is 120 ° or less, and if it is too large, the friction with the photoreceptor becomes too small, and the primary transfer efficiency of the toner is deteriorated. The contact angle of the coat layer with water is most preferably 90 ° or more and 105 ° or less.
If the surface roughness (Ra) of the coat layer is small and the surface is smooth, even if the contact angle with water is relatively large, the toner cleaning property and the toner transfer property are good, in other words, the surface roughness. If the contact angle is rough, cleaning can be facilitated by reducing the contact angle with water.

<Bend resistance (fold resistance)>
When the laminated endless belt of the present invention is used in an image forming apparatus as an intermediate transfer belt, for example, a laminated endless belt having good bending resistance is preferred because cracks occur and images cannot be obtained if the bending resistance is poor.

The degree of bending resistance can be quantitatively evaluated by following the method for measuring the folding endurance of JIS P-8115, and it is judged that an endless belt with a higher folding endurance is less susceptible to cracking and has superior bending resistance. be able to.
As a specific numerical value, if it exceeds 5000 times, it can be used with an excellent function as an endless belt for the life of the apparatus, but practically it is preferably 8000 times or more and preferably 10,000 times or more. More preferably.

  According to the present invention, depending on the amount of thermoplastic elastomer added to the base material layer and alloying, the laminated endless belt can have a folding endurance of 50,000 times or more, and further 100,000 or more. It is preferable because sufficient crack resistance can be obtained without performing secondary processing such as a reinforcing tape for preventing cracks that is usually used to prevent cracks from occurring in the portion.

  In order to obtain the bending resistance of the laminated endless belt, the bending resistance of the base material layer of the laminated endless belt is preferably 8000 times or more, particularly 10,000 times or more as the number of folding times.

[Applications of laminated endless belts for image forming devices]
Although there is no restriction | limiting in particular in the use of the lamination | stacking endless belt for image forming apparatuses of this invention, It can use suitably for the OA apparatus field | area with a severe request | required physical property, such as a dimensional accuracy, bending resistance, and a tensile elasticity modulus, especially. When this laminated endless belt is formed into a seamless belt shape, there are few problems such as cracking and elongation, which is preferable.

  The laminated endless belt for an image forming apparatus of the present invention is used in an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, and a facsimile machine, particularly an intermediate transfer belt, a transfer transfer belt, a transfer fixing belt, a fixing belt, and a photoreceptor belt. It can be suitably used as a development sleep, especially as an intermediate transfer belt, a conveyance transfer belt, a photosensitive belt, and the like.

  The laminated endless belt of the present invention may be used as it is, or may be wound around a drum or a roll.

  Further, for the purpose of reinforcing the end face, a reinforcing tape such as a heat-resistant tape may be bonded to the outer side and / or the inner side of the laminated endless belt along the side edge as necessary. As the reinforcing tape, a biaxially stretched polyester tape is preferable in terms of cost and strength, and the tape width is preferably 4 mm or more and 20 mm or less because the apparatus layout is compact. The thickness of the reinforcing tape is preferably 20 μm or more and 200 μm or less from the standpoint that the endless belt can be driven with low tension and crack resistance is prevented because the flexibility is maintained.

  Further, for the purpose of preventing meandering of the laminated endless belt, a rubber sheet (meandering prevention guide) such as urethane rubber or silicon rubber may be bonded to the side edge of the endless belt with an adhesive. In this case, the preferable sheet width of the rubber sheet to be used is 2 to 10 mm, and 3 to 8 mm is particularly preferable in view of the layout of the apparatus and the adhesive strength. Further, from the viewpoint of preventing meandering, the thickness of the meander-preventing rubber is preferably 0.5 to 3 mm, and more preferably 0.7 to 2 mm from the viewpoint of simplicity of the meandering prevention and meandering preventing effect.

  Furthermore, in combination with the above-mentioned reinforcing tape, it is preferable that the reinforcing tape is bonded to the laminated endless belt and then the meandering prevention guide is bonded to the belt because of the effect of preventing the occurrence of belt cracking and the belt meandering.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Materials used]
{Substrate layer forming material}
The material for forming the base material layer was as follows, and the blending ratio was as shown in Tables 2 and 3.
<Thermoplastic elastomer>
(PEER)
Polyester-polyester elastomer "Perprene S3001" manufactured by Toyobo Co., Ltd.
MFR (240 ° C., 2.16 kgf load): 21 g / 10 minutes,
DSC crystal melting point: 216 ° C
Glass transition temperature: 40 ° C

<Thermoplastic resin>
(PBT)
Polybutylene terephthalate manufactured by Mitsubishi Engineering Plastics Co., Ltd.
"Novaduran 5040ZS"
Weight average molecular weight: 40,000
MFR (240 ° C., 2.16 kgf load): 4 g / 10 min
DSC crystal melting point: 229 ° C
Glass transition temperature: 40 ° C
(ETFE)
Asahi Glass Co., Ltd. ethylene tetrafluoroethylene copolymer "Aflon C55AP"
(PVDF)
Polyfluorinated vinylidene "Kyner 720" manufactured by Arkema
(PA12)
Polyamide (nylon 12) “UBESTA3030U” manufactured by Ube Industries, Ltd.

<Carbon black>
Acetylene black "DENKA BLACK" manufactured by Denki Kagaku Co., Ltd.
DBP oil absorption: 180ml / 100g
Specific surface area: 65 m ² / g
Volatile content: 0%
Average primary particle size: 39 nm
pH: 9

<Conductive metal oxide filler>
Aluminum doped zinc oxide “23-KB” average particle size 1.5 μm manufactured by Hakusui Chemical Co., Ltd.

<Antistatic agent>
Polyester ester amide manufactured by Ciba Specialty Chemicals
"IRGAATAT P16"

<Antioxidant>
Phosphoric antioxidant “PEPQ” manufactured by Clariant Japan

<Additional ingredients>
(Silicone oil)
Dimethyl silicone oil “SH200” manufactured by Toray Dow Corning Co., Ltd.
Functional group equivalent: 5000 or more
Average molecular weight: 4400
(Applied to carbon black by 0.33% by weight and used after heat treatment.)
(Silane compound)
Perfluoroalkylsilane "KBM-7103" manufactured by Shin-Etsu Chemical Co., Ltd.
(Used by adding 0.3% by weight to aluminum-doped zinc oxide and heat treatment.)

{Coating layer forming material}
The crosslinkable liquid material (coating material) for forming the coating layer was prepared as follows using the following materials.

<Coating material preparation material>
“OPSTAR TU4106” manufactured by JSR: 22.5% by weight of polyfunctional acrylate monomer as solid content, 27.5% by weight of phosphorus-doped tin oxide (average primary particle size 10 nm), and 50% by weight of propylene glycol monomethyl ether as a diluent solvent Coated material “UA-160TM” manufactured by Shin-Nakamura Chemical Co., Ltd .: Coated material of urethane acrylate oligomer 100% by weight “OPSTAR Z7535” manufactured by JSR Co., Ltd .: 25% by weight of polyfunctional acrylate monomer as solid content, amorphous having acrylic group on the surface "X12-3400" coating material manufactured by Shin-Etsu Chemical Co., Ltd .: 25% by weight of silica fine particles (average primary particle size 10 nm), 5% by weight of methyl ethyl ketone, 35% by weight of methyl isobutyl ketone, and 10% by weight of cyclohexanone as a diluent solvent Acrylic Silicone Coating Material “NK Ester A-DPH” manufactured by Shin-Nakamura Chemical Co., Ltd .: Coating material of 100% by weight of dipentaerythritol polyacrylate “T-1” manufactured by Mitsubishi Materials Corporation: Average primary particle diameter 20 nm, powder volume resistance 1 Antimony-doped tin oxide of 5 Ω · cm “IRGACURE 184” manufactured by BASF Japan Ltd .: 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator “BYK-UV3500” manufactured by Big Chemie Japan Ltd .: acrylic group-containing poly as an antifouling component Ether-modified polydimethylsiloxane

<Coating material 1>
JSR "OPSTAR TU4106" 100 parts by weight, Big Chemie Japan "BYK-UV3500" 0.05 parts by weight, acetophenone photopolymerization initiator 1-hydroxycyclohexyl phenyl ketone 3 parts by weight, propylene glycol as a diluent solvent 100 parts by weight of monoethyl ether was prepared. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 11.08 wt%,
Phosphorus-doped tin oxide 13.54% by weight,
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 24.62% by weight
Propylene glycol monoethyl ether 49.25% by weight

<Coating material 2>
70 parts by weight of "OPSTAR TU4106" manufactured by JSR, 15 parts by weight of "NK Ester A-DPH" manufactured by Shin-Nakamura Chemical Co., Ltd., 0.05 parts by weight of "BYK-UV3500" manufactured by BYK Japan, acetophenone photopolymerization initiator 3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 100 parts by weight of propylene glycol monoethyl ether as a diluent solvent, and 15 parts by weight of propylene glycol monomethyl ether were prepared. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 7.76% by weight
7.39% by weight of dipentaerythritol polyacrylate,
9.48% by weight of phosphorus-doped tin oxide,
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 24.62% by weight
Propylene glycol monoethyl ether 49.25% by weight

<Coating material 3>
90 parts by weight of "OPSTAR TU4106" manufactured by JSR, 10 parts by weight of "OPSTAR Z7535", 0.05 part by weight of "BYK-UV3500" manufactured by BYK Japan KK, 1-hydroxycyclohexyl phenyl ketone 3 as an acetophenone photopolymerization initiator 100 parts by weight of propylene glycol monoethyl ether as a diluent solvent was prepared. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 11.20% by weight
Amorphous silica fine particles 1.23 wt%
12.19% by weight of phosphorus-doped tin oxide,
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 22.16% by weight
Propylene glycol monoethyl ether 49.25% by weight
Methyl isobutyl ketone 1.72% by weight
Methyl ethyl ketone 0.25% by weight
Cyclohexanone 0.49% by weight

<Coating material 4>
70 parts by weight “OPSTAR TU4106” manufactured by JSR, 7.5 parts by weight “NK Ester A-DPH” manufactured by Shin-Nakamura Chemical Co., Ltd., 7.5 parts by weight “UA-160TM” manufactured by Shin-Nakamura Chemical Co., Ltd., Big Chemie Japan "BYK-UV3500" 0.05 parts by weight, 1 part of 1-hydroxycyclohexyl phenyl ketone as an acetophenone photopolymerization initiator, 100 parts by weight of propylene glycol monoethyl ether and 15 parts by weight of propylene glycol monomethyl ether as dilution solvents Liquid. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 7.76% by weight
Dipentaerythritol polyacrylate 3.69% by weight
Urethane acrylate oligomer 3.69% by weight
9.48% by weight of phosphorus-doped tin oxide,
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 24.62% by weight
Propylene glycol monoethyl ether 49.25% by weight

<Coating material 5>
70 parts by weight of “Optstar TU4106” manufactured by JSR, 7.5 parts by weight of “UA-160TM” manufactured by Shin-Nakamura Chemical Co., Ltd., 7.5 parts by weight of “X12-3400” manufactured by Shin-Etsu Chemical Co., Ltd., “BYK” manufactured by BYK Japan -UV3500 "0.05 parts by weight, 1 part of 1-hydroxycyclohexyl phenyl ketone of acetophenone photopolymerization initiator, 100 parts by weight of propylene glycol monoethyl ether and 15 parts by weight of propylene glycol monomethyl ether were prepared as diluent solvents. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 7.76% by weight
Urethane acrylate oligomer 3.69% by weight
Fluorine-modified acrylic silicone 3.69% by weight
Phosphorus-doped tin oxide 9.48% by weight
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 24.62% by weight
Propylene glycol monoethyl ether 49.25% by weight

<Coating material 6>
30 parts by weight of "OPSTAR TU4106" manufactured by JSR, 35 parts by weight of "NK Ester A-DPH" manufactured by Shin-Nakamura Chemical Co., Ltd., 0.05 parts by weight of "BYK-UV3500" manufactured by BYK Japan, acetophenone-based photopolymerization initiator 3 parts by weight of 1-hydroxycyclohexyl phenyl ketone, 100 parts by weight of propylene glycol monoethyl ether and 35 parts by weight of propylene glycol monomethyl ether as a diluent solvent were prepared. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 3.32% by weight
17.24% by weight of dipentaerythritol polyacrylate,
Phosphorus-doped tin oxide 4.06% by weight,
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 24.62% by weight
Propylene glycol monoethyl ether 49.25% by weight

<Coating material 7>
JSR "OPSTAR Z7535" 100 parts by weight, Big Chemie Japan "BYK-UV3500" 0.05 parts by weight, acetophenone photopolymerization initiator 1-hydroxycyclohexyl phenyl ketone 3 parts by weight, propylene glycol as a diluent solvent 100 parts by weight of monoethyl ether was prepared. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
Multifunctional acrylate monomer 12.31% by weight
Amorphous silica fine particles 12.31 wt%
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monoethyl ether 49.25% by weight
Methyl isobutyl ketone 17.24% by weight
Methyl ethyl ketone 2.46% by weight
Cyclohexanone 4.92% by weight

<Coating material 8>
80 parts by weight of "OPSTAR TU4106" manufactured by JSR, 10 parts by weight of "T-1" manufactured by Mitsubishi Materials, 0.05 part by weight of "BYK-UV3500" manufactured by BYK Japan KK, 1- 3 parts by weight of hydroxycyclohexyl phenyl ketone, 100 parts by weight of propylene glycol monoethyl ether as a diluent solvent, and 10 parts by weight of propylene glycol monomethyl ether were prepared. The blending weight% of each component of the obtained coating material is as follows.

(Solid content)
8.86% by weight of polyfunctional acrylate monomer,
Phosphorus-doped tin oxide 10.83 wt%
Antimony oxide doped tin oxide 4.92% by weight
Acrylic group-containing polyether-modified polydimethylsiloxane 0.02% by weight
1-hydroxycyclohexyl phenyl ketone 1.48% by weight
(Diluted solvent)
Propylene glycol monomethyl ether 24.62% by weight
Propylene glycol monoethyl ether 49.25% by weight

The content of the metal filler and the content of the photopolymerization initiator in the solid content of the coating materials 1 to 8 are as shown in Table 1.
Moreover, about the surface electrical resistivity of the coating layer of the below-mentioned lamination | stacking endless belt about the cured film obtained by apply | coating said coating materials 1-8 on a PET film so that it might each become thickness 1 micrometer, and bridge | crosslinking by ultraviolet irradiation. SV (10 V) measured in the same manner as the measurement method was as shown in Table 1.

[Heat kneading]
Each base material layer molding material described in Tables 2 and 3 was pelletized using a twin-screw kneading extruder (“PMT32” manufactured by IKG Corporation). The kneading conditions were basically a cylinder temperature of 260 ° C. in Examples 1 to 6 and Comparative Examples 1 to 3, but the cylinder temperature of the kneading part where the temperature of the molten resin rises midway is set to 230 ° C. to 250 ° C. The temperature was adjusted in the range from 220 ° C to 270 ° C.
In Example 7, the cylinder temperature was 280 ° C, in Example 8, the cylinder temperature was 210 ° C, and in Example 9, the cylinder temperature was 270 ° C.

[Formation of base material layer]
The pellets of the molding material of each base material layer obtained above were dried at 130 ° C., extruded in a molten tube state below the annular die by a 40 mmφ extruder with a 6-thread spiral annular die having a diameter of 210 mm, and melted by extrusion. The tube was placed in the melting tube while being cooled and solidified by contacting the outer surface (temperature 90 ° C.) of a cooling mandrel with an outer diameter of 208 mm mounted on the same axis as the annular die via a support rod. A cylindrical belt and a four-point belt type take-up machine installed on the outside were used to cut a seamless belt-like base material layer into a length of 300 mm while holding the cylindrical shape. The take-up speed is 1.2 m / min, and the inner diameter is 207 mm while adjusting the extrusion amount, the extrusion temperature, and the cooling temperature so that the surface electrical resistivity shown in Tables 2 and 3 is obtained with the base material layer thickness shown in Tables 2 and 3. The base material layer was obtained.

Extrusion conditions were as follows: in Examples 1-6 and Comparative Examples 1-3, the cylinder and die temperatures were both 260 ° C., 300 ° C. in Example 7 and 200 ° C. in Example 8. In Example 9, the temperature was 270 ° C.
The die mold conditions were as follows: in Examples 1-5 and Comparative Examples 1-3, the die mold lip clearance was 2.0 mm, and in Examples 6-9, it was 1.5 mm. Therefore, the ratio of the thickness of the base material layer / the lip clearance of the extrusion die is as shown in Tables 2 and 3.

  The base material layer thicknesses shown in Tables 2 and 3 are average thicknesses measured with an electric micrometer at a pitch of 3 mm in the circumferential direction of the base material layer.

[Formation of coat layer]
<Plasma treatment>
In Examples 7 and 8, plasma treatment was performed on the outer surface of the base material layer under the following conditions before the coating layer was applied.
The base layer is packaged on a cylindrical drum having an outer diameter that is 1 mm smaller than the inner diameter of the base layer, and the remote drum is manufactured by Nippon Plasma Treat Co., Ltd. while rotating the cylindrical drum so that the rotational speed of the base layer is 10 m / min. Plasma treatment was performed on the outer surface of the base material layer using a pressure plasma treatment apparatus. The nozzle diameter of the nozzle used for the plasma treatment is 20 mm, the nozzle is attached to a uniaxial robot, the distance between the nozzle tip and the base material layer is 6 mm, and the width of the base material layer (axial direction) is 5 mm / second. It was moved at the moving speed.
Plasma treatment was not performed for Examples 1 to 6, 9 and Comparative Examples 1 to 3.

<Coating material application>
The base material layer is mounted on the outside of a cylindrical drum having an outer diameter of 207 mm, and this drum is rotated so that the rotational speed of the base material layer is 360 m / min. The coating materials shown in Tables 2 and 3 were applied by spraying at an amount of 5.0 g / min so that the coating layers having the thicknesses shown in Tables 2 and 3 were formed on the outer surface of the base material layer.
The spray nozzle was mounted on a uniaxial robot and moved at a moving speed of 20 mm / min in the base material layer width direction (axial direction).

<Ultraviolet crosslinking>
The base material layer coated with the coating material is dried with a hot air dryer at 60 ° C. for 3 minutes while rotating the drum at a rotational speed of 10 m / min, and then coated with a handy 600 WUV device manufactured by GS Yuasa Co., Ltd. The coating layer was formed by cross-linking and curing the coating material coating film by irradiating ultraviolet rays for 3 minutes so that the integrated irradiation energy was 500 mJ / cm ² and the distance to the film was 50 mJ / cm ² , thereby obtaining a laminated endless belt. .

[Evaluation]
The obtained laminated endless belt and its constituent layers were evaluated, and the results are shown in Tables 2 and 3.

<Surface electrical resistivity>
A product name “Hiresta (UR100 terminal)” manufactured by Dia Instruments Co., Ltd. was used, and measurement was performed under conditions of an applied voltage of 10 V, 100 V, 250 V, 500 V, or 1000 V for 10 seconds each.
However, in the measurement of 10V value, the measurement of 1 × 10 ¹³ Ω or more is suitable for the measurement of the high resistance region. The JIS electrode is connected to the product name “R8340A” made by Advantest Co., Ltd. Measured.
The surface electrical resistivity of the base material layer was measured with respect to the outer surface of the base material layer obtained by extrusion molding.
The surface electrical resistivity of the coating layer is such that a PET film having a thickness of 100 μm is wound around the base material layer before forming the coating layer, and each coating material is produced on this PET film, and the coating layer is produced on the base material layer. The coating layer was formed by applying and curing under the same conditions as the conditions, and the coating layer was measured.
The surface electrical resistivity of the laminated endless belt was measured with respect to the outer surface (coat layer surface) of the laminated endless belt obtained by forming a coat layer on the base material layer.

<Surface roughness Ra>
About the base material layer and the laminated endless belt, test pieces each having a size of about 50 mm × 50 mm were cut out, and the surface (outer side) was used with a key depth ultra-deep shape measuring microscope “VK8500” manufactured by Keyence Corporation. The surface roughness Ra of an area of 40 μm × 40 μm was measured at four points under the measurement conditions of a pitch of 0.01 μm, a shutter speed AUTO, and a gain 835, and the average value was taken as the measured value of the surface roughness.

<Contact angle with water>
For each of the laminated endless belts, a drop of water was dropped on the outer surface, and the contact angle of water after 1 minute was measured using an Elmer goniometer “G-1.”

<Friction coefficient>
The outer surface of the multilayer endless belt was measured static friction coefficient between the hard chrome plated plates brass with Shinto Kagaku Co. "HEIDON Toraihogia μ ^S TYPE94i".

<Tensile modulus>
In accordance with ISO R1184-1970, a test piece having a width of 15 mm and a length of 150 mm was cut from the base material layer and the laminated endless belt, respectively, and a tensile speed of 1 mm / min and a distance between grips of 100 mm with respect to this test piece. As measured.

<Bend resistance (fold resistance)>
In accordance with JIS P-8115, test pieces each having a width of 15 mm and a length of 100 mm were cut from the base material layer and the laminated endless belt, and the bending speed of the test piece was 175 times with an MIT tester. / Fold, rotation angle of 135 ° right and left, and a tensile load of 1.0 kgf, a bending jig having a radius of curvature R = 0.38 mm at the tip was used to measure the number of bendings that led to each fracture. The average value of 3 points was used.

<Durability>
A laminated endless belt is stretched around two φ20mm rollers with a tension of 4kg and rotated to evaluate whether the endless belt will crack when it is rotated 60,000 times. “○” indicates that the output can be performed without any crack, and “△” indicates that the output can be performed without generating a crack of 30,000 times or more and less than 60,000 times, and “×” indicates the value less than that.

<Cleanability>
Mount the laminated endless belt on the transfer belt unit of Ricoh's intermediate transfer tandem machine "Ipsio SP C220", attach the cleaning blade, and turn the waste toner in contact with the belt surface. Count the number of toner remaining in a streak form after the belt 10 rotates without being cleaned by the blade. If it is 3 places or less, it is “◯”, and if it is more than 3 places and 10 places or less, it is “△” and exceeds 10 places. In this case, “x” was used.

<Image evaluation>
A laminated endless belt was mounted on a transfer belt unit of an intermediate transfer tandem machine “IPSiO SP C220” manufactured by Ricoh Co., Ltd., and a 4 cm × 5 cm black solid image was printed. The degree of white spots in the solid image was visually confirmed. If the printer image was improved from the printer image at the time of purchase, “◯” was indicated. Otherwise, “X” was indicated.

  In Examples 1 to 9 and Comparative Examples 1 to 3, the mixing ratio of carbon black contained in the base material layer of the laminated endless belt to the base material layer (described as “carbon black content” in Table 4). The blending ratio of the metal filler contained in the coating layer to the coating layer (described as “metal filler blending amount” in Table 4) is as shown in Table 4.

[Discussion]
<Example 1>
13.0 parts by weight of acetylene black surface-treated with silicone oil is blended with 100 parts by weight of a thermoplastic polymer component in which 30% by weight of a thermoplastic elastomer is blended with 70% by weight of PBT, and the thickness is 120 μm, SR (10V) 7.1 × the extruded base layer 10 ¹⁰ Omega, using a coating material 1, the thickness 1μm, SR (10V) 3.0 × 10 10 Ω laminated endless belt to form a semiconductive coating layer of the SR (10V ) Is 1.3 × 10 ¹⁰ Ω, and this laminated endless belt satisfies the conditions (1), (2), and (3), and therefore the surface electrical resistivity of the laminated endless belt depends on the applied voltage. Therefore, a good image can be obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning properties.

<Example 2>
The SR (10 V) of the laminated endless belt produced in the same manner as in Example 1 except that the coating material 2 was used for forming the coat layer was 3.9 × 10 ¹⁰ Ω. ), (2), and (3) are all satisfied, the surface electrical resistivity of the laminated endless belt can be made less dependent on the applied voltage, and a good image can be obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning properties.

<Example 3>
The laminated endless belt produced in the same manner as in Example 1 except that the coating material 3 was used for forming the coating layer had an SR (10 V) of 2.1 × 10 ¹⁰ Ω. ), (2), and (3) are all satisfied, the surface electrical resistivity of the laminated endless belt can be made less dependent on the applied voltage, and a good image can be obtained.
In addition, since the acryl in which the amorphous silica fine particles having an excellent surface smoothness, high surface hardness, and average primary particle diameter of 10 nm are dispersed is separated from the acryl in which the metal filler is dispersed, the amorphous silica fine particles by the blade are used. It was an endless belt with less toner scraping and excellent toner cleaning performance.

<Example 4>
The SR (10 V) of the laminated endless belt produced in the same manner as in Example 1 except that the coating material 4 was used for forming the coat layer was 7.7 × 10 ⁹ Ω. ), (2), and (3) are all satisfied, the surface electrical resistivity of the laminated endless belt can be made less dependent on the applied voltage, and a good image can be obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning properties.

<Example 5>
The SR (10 V) of the laminated endless belt produced in the same manner as in Example 1 except that the coating material 5 was used for forming the coat layer was 7.6 × 10 ⁹ Ω. ), (2), and (3) are all satisfied, the surface electrical resistivity of the laminated endless belt can be made less dependent on the applied voltage, and a good image can be obtained.
Further, by blending a fluorine-modified silicone coating material, a product having a high contact angle with water was obtained, and it was an endless belt having excellent surface smoothness, high surface hardness, and excellent toner cleaning properties.

<Example 6>
13.2 parts by weight of acetylene black surface-treated with silicone oil was blended with 100 parts by weight of the thermoplastic polymer component of 100% by weight of PBT, and extruded to a thickness of 100 μm and SR (10V) 2.3 × 10 ¹⁰ Ω. SR (10 V) of the laminated endless belt in which the semiconductive coating layer having a thickness of 0.4 μm and SR (10 V) of 3.0 × 10 ¹¹ Ω is formed on the base material layer using the coating material 3 is 9.0 ×. 10 ⁹ Ω, and this laminated endless belt is configured to satisfy all of the conditions (1), (2), and (3), so that the surface electrical resistivity of the laminated endless belt is less dependent on the applied voltage. And a good image was obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning performance.

<Example 7>
12.0 parts by weight of acetylene black and 100 parts by weight of perfluoroalkylsilane-treated Al-doped zinc oxide are blended with 100 parts by weight of thermoplastic polymer component 100% by weight of ETFE. 10 V) A semiconductive coating layer having a thickness of 1.5 μm and SR (10 V) of 3.0 × 10 ¹⁰ Ω was formed on the base material layer extruded to 1.0 × 10 ¹³ Ω using the coating material 3. The SR (10V) of the laminated endless belt is 1.6 × 10 ¹¹ Ω, and this laminated endless belt is configured to satisfy all of the conditions (1), (2), and (3). It was possible to make the electrical resistivity less dependent on the applied voltage, and a good image was obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning performance.

<Example 8>
15.0 parts by weight of polyether ester amide as a non-carbon antistatic agent is blended with 100 parts by weight of PVDF 100% by weight of the thermoplastic polymer component, resulting in a thickness of 100 μm, SR (10V) 5.2 × 10 ¹¹ Ω. The SR (10 V) of the laminated endless belt in which a semiconductive coating layer having a thickness of 0.5 μm and SR (10 V) of 3.0 × 10 ¹¹ Ω is formed on the extruded base material layer using the coating material 3 is 3 0.0 × 10 ¹¹ Ω, and this laminated endless belt is configured to satisfy all of the conditions (1), (2), and (3), so that the surface electrical resistivity of the laminated endless belt is less dependent on the applied voltage. And a good image was obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning performance.

<Example 9>
A base material layer coated with 18.0 parts by weight of acetylene black to 100 parts by weight of a thermoplastic polymer component with 100% by weight of PA and extruded to a thickness of 140 μm and SR (10 V) of 3.0 × 10 ¹² Ω is coated. SR (10V) of the laminated endless belt in which the semiconductive coating layer having a thickness of 1 μm and SR (10V) of 1.0 × 10 ¹¹ Ω is formed using the material 3 is 1.0 × 10 ¹² Ω. Since the endless belt is configured to satisfy all the conditions (1), (2), and (3), the surface electrical resistivity of the laminated endless belt can be less dependent on the applied voltage, and a good image can be obtained. Obtained.
Further, the endless belt had excellent surface smoothness, high surface hardness, and excellent toner cleaning performance.

  As described above, each of the laminated endless belts of Examples 1 to 9 satisfies all of the conditions (1), (2), and (3) of the present invention, and is excellent as a laminated endless belt. As a result, it is considered that a good image was obtained.

<Comparative Example 1>
The coating layer was formed in the same manner as in Example 1 except that a coating layer having a low SR (10V) of 1.0 × 10 ¹⁴ Ω was formed using a coating material 6 having a low metal filler content and a high resistance. The laminated endless belt produced in this way has an SR (10 V) of 1.0 × 10 ¹⁴ Ω, and this laminated endless belt is an endless belt having surface smoothness, high surface hardness, and excellent toner cleaning properties. However, the structure does not satisfy the conditions (1), (2), and (3), the surface electrical resistivity of the laminated endless belt is highly dependent on the applied voltage, and only an image in which the toner is partially white is obtained. There wasn't.

<Comparative Example 2>
The coating layer was formed in the same manner as in Example 1 except that a high resistance coating material 7 containing no conductive component was used to form a coating layer having a SR (10 V) of 1.0 × 10 ¹⁴ Ω. The laminated endless belt produced in this manner has an SR (10 V) of 1.0 × 10 ¹⁴ Ω, and this laminated endless belt has surface smoothness, high surface hardness, and excellent toner cleaning properties. However, the structure does not satisfy the conditions (1), (2), and (3), the surface electric resistivity of the laminated endless belt is highly dependent on the applied voltage, and only an image in which the toner is partially white is obtained. It was.

<Comparative Example 3>
Example except that the coating layer was formed using a low-resistance coating material 8 with a large amount of metal filler and a thickness of 2 μm and a SR (10 V) of 1.0 × 10 ⁷ Ω. The laminated endless belt produced in the same manner as in Example 1 has an SR (10 V) of 5.9 × 10 ⁸ Ω, and this laminated endless belt has surface smoothness, high surface hardness, and excellent toner cleaning properties. Although it is a belt, it does not have a configuration satisfying the conditions (1), (2), and (3), the surface electric resistivity of the laminated endless belt is highly dependent on the applied voltage, and the toner is partially whitened. Only obtained.

  The laminated endless belts of Comparative Examples 1 to 3 were combined with a large difference in surface electrical resistance between the base material layer and the coating layer, or a coating layer having a large voltage dependency on the surface electrical resistance was selected. In addition, since a material having a large electric resistance value of the coat layer was selected, the dependency of the surface electric resistivity of the laminated endless belt on the applied voltage became large, and the electric resistance value was unstable, so that an image abnormality occurred. This is presumed to be caused by a discharge generated between the paper and the endless belt.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure optical system 4 Developer 5 Cleaner 6 Conductive endless belt 7, 8, 9 Conveyance roller

[1] A laminated endless belt used in an image forming apparatus, comprising at least a base material layer and a coat layer formed on the base material layer and having a thickness of 0.2 μm or more and less than 2.0 μm, coat layer is made by blending a metal filler to an active energy ray and / or thermally crosslinked resin, the content of the metal filler is 20 wt% or more, laminating the image forming apparatus, characterized in that not more than 60 wt% Endless belt.
[2] The laminated endless belt for an image forming apparatus according to [1], wherein the metal filler powder has a volume resistance of 5 to 10 ⁶ Ω · cm.
[3] The laminated endless belt for an image forming apparatus according to [1] or [2], wherein the metal filler is tin oxide doped with phosphorus.
[4] The laminated endless belt for an image forming apparatus according to any one of [1] to [3], wherein the metal filler has an average primary particle size of 30 nm or less.
[5] An image forming apparatus comprising the laminated endless belt for an image forming apparatus according to any one of [1] to [4].

Claims (14)

A laminated endless belt used in an image forming apparatus, comprising at least a base material layer and a coat layer formed on the base material layer and having a thickness of 0.2 μm or more and less than 2.0 μm,
The coat layer is formed by blending an active energy ray and / or a thermally crosslinked resin with a metal filler, and the content of the metal filler is 20% by weight or more and 60% by weight or less,
SR (10V) is the surface electrical resistivity measured at an applied voltage of 10V for 10 seconds.
When the surface electrical resistivity measured at an applied voltage of 1000 V for 10 seconds is SR (1000 V),
The surface electrical resistivity of the coating layer satisfies the following conditions (1) and (2), and the surface electrical resistivity of the base material layer and the surface electrical resistivity of the coating layer satisfy the following condition (3). A laminated endless belt for an image forming apparatus.
(1) SR (10V) of coat layer = 3 × 10 ⁸ Ω or more, 3 × 10 ¹³ Ω or less
(2) SR (10V) / SR (1000V) of the coating layer = 10 or less
(3) SR (10V) of base material layer / SR (10V) of coat layer = 0.001 or more, 500 or less   2. The laminated endless belt for an image forming apparatus according to claim 1, wherein the coating layer thickness / base material layer thickness ratio is 1/750 or more and 1/100 or less.   3. The laminated endless belt for an image forming apparatus according to claim 1, wherein the average primary particle diameter of the metal filler is 30 nm or less.   4. The laminated endless belt for an image forming apparatus according to claim 1, wherein the metal filler is tin oxide doped with phosphorus. 5.   The laminated endless belt for an image forming apparatus according to any one of claims 1 to 4, wherein the active energy ray and / or the thermal crosslinking resin is a resin obtained by crosslinking an acrylic monomer and / or an acrylic oligomer. .   6. The substrate layer according to claim 1, wherein the base material layer is selected from the group consisting of a resin having an ester bond, a polyfluorinated vinylidene, an ethylenetetrafluoroethylene copolymer, a polyamide, and a thermoplastic elastomer. A laminated endless belt for an image forming apparatus, which is a seamless belt obtained by extrusion molding a molding material obtained by heating and mixing a thermoplastic polymer component mainly composed of two or more species and a conductive component.   The base material layer according to any one of claims 1 to 6, wherein the base layer is formed by blending a conductive component mainly composed of carbon black with a polymer component, and the coat layer is composed mainly of the metal filler. A conductive component is blended with a polymer component, and the polymerization ratio of the metal filler in the coat layer to the coat layer is greater than the polymerization ratio of carbon black in the substrate layer to the substrate layer. Laminated endless belt for image forming apparatus.   8. The laminated endless image forming apparatus according to claim 1, wherein the intermediate endless belt is a seamless intermediate transfer belt, a conveyance transfer belt, a transfer fixing belt, a fixing belt, a photosensitive belt, or a development sleep. belt.   A method for producing a laminated endless belt for an image forming apparatus according to any one of claims 1 to 8, wherein a coating film is formed on a surface of the base material layer by applying a crosslinkable liquid material. A method for producing a laminated endless belt for an image forming apparatus, comprising a step of forming the coat layer by crosslinking and curing the coating film with active energy rays and / or heat.   The image forming apparatus according to claim 9, wherein the base layer is formed by extrusion molding, and the coating layer is formed by spraying the crosslinkable liquid material on the rotating base layer. A method for producing a laminated endless belt. 11. The production of an endless belt for an image forming apparatus according to claim 9, wherein the base material layer is formed by extrusion molding that satisfies any one or more of the following conditions (a) to (c). Method.
(A) The melt tube take-off speed during extrusion molding is 1.0 m / min or more. (B) The ratio of the thickness of the base material layer / the lip clearance of the extrusion die mold is 0.12 or less. (C) The average of the base material layer. Thickness is 120μm or less   The crosslinkable liquid material according to any one of claims 9 to 11, wherein the crosslinkable liquid material is applied by spray coating, and a discharge amount of the crosslinkable liquid material at the time of spray coating is 0.1 g / min or more and 10 g / min or less. A method for producing a laminated endless belt for an image forming apparatus.   13. The crosslinkable liquid according to claim 9, wherein the crosslinkable liquid contains propylene glycol monomethyl ether and / or propylene glycol monoethyl ether as a diluting solvent for the active energy ray and / or the thermal crosslinking resin. A method for producing a laminated endless belt for an image forming apparatus.   The image manufactured by the manufacturing method of the lamination | stacking endless belt for image forming apparatuses of any one of Claims 1 thru | or 8, or the lamination | stacking endless belt for image forming apparatuses of any one of Claims 9 thru | or 13. An image forming apparatus comprising a laminated endless belt for a forming apparatus.

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