JP2006133472A - Electrophotographic seamless belt, method for producing electrophotographic seamless belt, and image forming apparatus having electrophotographic seamless belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic seamless belt superior in filming resistance to cleaning and toner by possessing uniform toner transfer property. <P>SOLUTION: The electrophotographic seamless belt 5 contains at least 30-90 mass% of a polyacetal resin, and 1-35 mass% of polyether ester amide or polyether amide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic seamless belt such as an intermediate transfer belt and a transfer conveyance belt used in an image forming apparatus, a method for producing an electrophotographic seamless belt, and an image forming apparatus having the electrophotographic seamless belt.

  An image forming apparatus using an intermediate transfer belt that is one of transfer members is an image in which a plurality of component color images of color image information and multicolor image information are sequentially stacked and transferred to synthesize and reproduce a color image and a multicolor image. It is effective as a color image forming apparatus or a multicolor image forming apparatus for outputting a formed product, or an image forming apparatus having a color image forming function or a multicolor image forming function.

For a color image forming apparatus using an intermediate transfer belt, as a conventional technique, a second image carrier is attached or adsorbed on a transfer drum, and an image is transferred from the first image carrier to the second image carrier. There is an image forming apparatus having a transfer device (see, for example, Patent Document 1). Compared with such a transfer device, in the image forming apparatus using the intermediate transfer belt, the transfer material as the second image carrier is not subjected to any processing or control (for example, gripped, adsorbed, or curved). The image can be transferred from the intermediate transfer belt to the transfer material without the necessity of providing it). For this reason, the second image carrier, regardless of whether it is wide or narrow, from thin paper (40 g / m ² paper) to thick paper (200 g / m ² paper) such as envelopes, postcards, and label papers. Has the advantage that a wide variety can be selected. Accordingly, color copiers and color printers using an intermediate transfer belt are already in use on the market.

  A color image forming apparatus using a belt-like transfer conveyance belt as a transfer conveyance member which is one of transfer members in the image forming apparatus is also known. In such an image forming apparatus, a plurality of image forming units are arranged in parallel, and images formed on an image carrier (photosensitive drum) in each unit are sequentially superimposed and transferred onto a transfer conveyance belt. A color image is obtained by transferring the image superimposed on the transfer conveyance belt onto a transfer material such as transfer paper. The color image forming apparatus using such a transfer / conveying belt is advantageous in that the color image is formed in one process because the color images are superimposed and transferred while sequentially transferring the transfer paper to each unit, so that the image output time is fast. There is. Therefore, color copiers, color printers, etc. using a transfer / conveying belt have already started to operate in the market.

  The electrophotographic seamless belt plays an important process in the process of forming an image, ie, transfer from the electrophotographic photosensitive member to the transfer material. To improve the quality of the image, the electrophotographic seamless belt is used. It is important to improve the characteristics of the belt.

  The characteristics required for the electrophotographic seamless belt include uniform toner transferability and toner cleaning properties in the image area, and it is important that the filming resistance to toner is good. As a seamless belt for electrophotography satisfying such characteristics, a belt using a fluorine-based resin as a surface layer base material can be given (for example, see Patent Documents 2 and 3). However, when these seamless belts are recycled, they can be melted and regenerated relatively easily if they are formed of a single fluororesin, but the seamless belts are actually formed of a composite of various resins. It is almost that. In this case, it is necessary to take a method of incinerating the seamless belt and performing thermal recycling. Incineration of the fluorine-based resin generates gas such as hydrogen fluoride, which causes damage to the incinerator. For this reason, using a fluorine-based resin as a main material such as a base material has a problem in recycling.

  Resins other than fluorine-based resins that have excellent transferability and toner cleaning properties include polyacetal resins (POM) with high lubricity. An electrophotographic seamless belt using this POM has also been proposed (see, for example, Patent Document 4). However, since POM has very high crystallinity, the molding shrinkage rate is very high. When the POM is molded into a thin film, there is a problem that the variation in the film thickness increases and the molding stability is affected. Further, since the molding shrinkage rate is high, there is a problem that the dispersion of the conductive agent is likely to occur in the belt layer, and the resistance becomes large. As a result, variations in transfer occurred, and it was difficult to obtain good and uniform transfer properties and cleaning properties.

  As a method for reducing the molding shrinkage of the electrophotographic seamless belt using POM, a method of blending POM and an amorphous resin such as a thermoplastic elastomer can be mentioned. Moreover, as a method for reducing the variation in resistance of the obtained seamless belt, a method of using a polymer antistatic agent such as an ionic surfactant or polyether for the seamless belt can be mentioned. Therefore, the present inventors previously tried to reduce the variation in the film thickness and resistance of the seamless belt obtained by combining these materials with POM, but to the level that can satisfy these variations. It could not be resolved.

  In addition, the use of thermoplastic polyacetals, polymer alloys of thermoplastic polyacetals and thermoplastic elastomers, or polymer blends of thermoplastic polyacetals and thermoplastic elastomers as a base material has been proposed to improve the bending resistance of seamless belts. However, the method for controlling the variation in film thickness and the variation in resistance caused by the high molding shrinkage property of POM is not mentioned and is insufficient (for example, see Patent Document 5).

Furthermore, although resin compositions of POM and polyacetal, polyether ester amide, and polyolefin resin are known, there is no mention of a method for improving transferability and cleaning performance when this is used as a seamless belt for electrophotography. .
JP-A-63-301960 JP-A-7-92825 JP-A-9-106196 JP 2001-350346 A JP 2002-146212 A

  It is an object of the present invention to provide an electrophotographic seamless belt that solves the above problems, a method for producing the electrophotographic seamless belt, and an image forming apparatus using the electrophotographic seamless belt.

  That is, it is an object of the present invention to provide an electrophotographic seamless belt that has excellent moldability, uniform toner transferability, and excellent cleaning properties and filming resistance to toner. Another object of the present invention is to provide a method for producing such an electrophotographic seamless belt and an image forming apparatus using the electrophotographic seamless belt.

That is, the present invention relates to a seamless belt for electrophotography characterized by containing 30 to 90% by mass of a polyacetal resin and 1 to 35% by mass of polyetheresteramide or polyetheramide.
The present invention also provides a molding raw material containing at least 30 to 90% by mass of a polyacetal resin and 1 to 35% by mass of a polyether ester amide or a polyether amide,
The raw material for molding is melt-extruded from an annular die to obtain a tubular melt,
Forming a tube by drawing the tube-like melt at a predetermined take-up speed while cooling,
The present invention relates to a method for producing a seamless belt for electrophotography, wherein the tube is cut to obtain a seamless belt.
Furthermore, the present invention is an image forming apparatus for forming an image by visualizing an electrostatic latent image formed on an image carrier with a developer, transferring the image onto a transfer material, and fixing the image. The present invention relates to an image forming apparatus having a seamless belt for electrophotography.

  As described above, according to the present invention, it is possible to obtain a high-quality electrophotographic seamless belt that has excellent moldability, does not cause image unevenness during transfer, and has excellent toner cleaning properties.

The present invention is described in detail below.
The electrophotographic seamless belt of the present invention (hereinafter also simply referred to as “seamless belt”) comprises at least 30 to 90% by mass of polyacetal resin (POM) and 1 to 35% by mass of polyetheresteramide or polyetheramide. It is characterized by containing. By adopting such a configuration, it is possible to obtain an electrophotographic seamless belt having uniform transfer properties and excellent cleaning properties without sticking to the mold during molding.

  The content of the polyacetal resin in the electrophotographic seamless belt is preferably 30 to 74% by mass, and more preferably 45 to 70% by mass. If the content of the polyacetal resin is less than 30% by mass, sufficient belt strength may not be obtained. On the other hand, when the content of the polyacetal resin is more than 90% by mass, the influence of the crystallinity of the polyacetal resin on molding shrinkage is increased, and film thickness unevenness is likely to occur.

  The polyacetal resin that can be used in the electrophotographic seamless belt in the present invention may be a polyoxymethylene homopolymer or a copolymer of oxymethylene and another monomer.

The seamless belt for electrophotography of the present invention contains polyether ester amide or polyether amide 1 to 35% as a conductive agent in order to adjust the electric resistance.
Examples of the material for controlling the resistance of the seamless belt generally include conductive inorganic fine particles such as carbon black, low molecular antistatic agents such as ionic surfactants, or polyethylene oxide polymer antistatic agents. . However, it is not possible to control variations in film thickness and resistance resulting from the high molding shrinkage rate of POM, which is a crystalline resin, by using only the materials described above. In addition, in low molecular antistatic resins such as ionic surfactants and polyethylene oxide polymer antistatic agents, the antistatic agent bleed-out cannot be controlled, and uniform transferability, It is difficult to obtain a cleaning property.

  Therefore, in the seamless belt of the present invention containing POM, by using polyether ester amide or polyether amide as a conductive agent, molding stability, transferability, and cleaning properties can be satisfied at the same time.

The polyether ester amide that can be used in the seamless belt of the present invention is mainly composed of a copolymer comprising a polyamide block unit such as nylon 6, nylon 66, nylon 11 and nylon 12, and a polyether ester unit. Refers to a compound. Examples of the polyether ester unit used in the present invention include lactam, lactam salt, aminocarboxylic acid, aminocarboxylic acid salt, polyethylene glycol, dicarboxylic acid (for example, terephthalic acid, isophthalic acid, and adipic acid). And copolymers derived from the above.

Specific examples of the ether ether amide in the present invention include, for example, Pelestat NC6321, manufactured by Sanyo Chemical Co., Ltd., IRGASTAT P18 (manufactured by Ciba Specialty Chemicals), IRGASTAT P22 (manufactured by Ciba Specialty Chemicals), and the like. Can be obtained and used.

The polyether amide refers to a compound mainly composed of a copolymer composed of a polyamide block unit such as nylon 6, nylon 66, 11 or 12, and a polyether unit. In the description of the polyether ester amide and the polyether amide, the “main component” refers to a state containing 50% or more by mass ratio. As the polyether amide in the present invention, a polyether amide composed of nylon 12 and polytetramethylene ether glycol can be preferably used.
The polyether ester amide and the polyether amide can be produced by a known polymerization method.

  The seamless belt of the present invention contains 1 to 35% by mass of the above polyether ester amide or polyether amide. These contents are preferably 2 to 20% by mass, and more preferably 13 to 15% by mass. In the present invention, if the content of polyetheresteramide or polyetheramide in the seamless belt is less than 1% by mass, the resistance value of the electrophotographic seamless belt is too high, and transfer failure may occur. On the other hand, when the content of the polyether ester amide or the polyether amide is more than 35% by mass, these are very soft and the elastic modulus and creep characteristics are deteriorated, so that the color shift may be deteriorated. Further, the seamless belt itself is sticky, resulting in deterioration of transferability and cleaning property.

  The seamless belt of the present invention may contain only the polyether ester amide in the above content, or may contain only the polyether amide in the above content, or the polyether ester amide and You may contain both polyether amides so that it may become the said content by the total amount. Of these, more preferable are those containing only the polyether ester amide in the above content together with the POM.

  In other words, polyether ester amide and polyether amide are sticky to the molding die during seamless belt molding, when used as a resistance control agent for thermoplastic resins due to the stickiness generated during thermoforming. By using together with POM having excellent properties, the problem of sticking can be solved while maintaining excellent transferability and cleaning properties.

  The seamless belt of the present invention may further contain conductive inorganic fine particles as shown below in addition to the POM and polyether ester amide or polyether amide. Conductive inorganic fine particles used in the seamless belt of the present invention, conductive carbon such as ketjen black and acetylene black; metal powder such as copper, nickel, iron and aluminum; metal such as titanium oxide, zinc oxide and tin oxide Although oxide powder etc. are mentioned, it is not restricted to said material.

  The conductive inorganic fine particles are preferably added in the range of 1 to 30% by mass of the total amount of the seamless belt. A more preferable addition amount is 1 to 20% by mass. If it is added in an amount of more than 30% by mass, the dispersibility of the conductive inorganic fine particles with respect to POM as the belt base material is deteriorated, resulting in variations in resistance of the resulting seamless belt, or a decrease in belt strength.

  The seamless belt of the present invention may further contain a fluorine-based additive as shown below. Fluorine-based additives used in the present invention, such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene-tetrafluoroethylene copolymer, and PFA; vinylidene fluoride-based fluororubber, propylene / tetra Fluorine rubber such as fluoroethylene-based fluororubber; Fluorine-based low molecular weight materials such as fluorinated alkyl ester are exemplified, but not limited to the above materials. In the present invention, as a method for incorporating the fluorine-based additive into the seamless belt, known methods such as powder dispersion and resin blending may be mentioned, but the method is not limited only to the above methods.

  In this invention, it is preferable to add the said fluorine-type additive in 0-25 mass% of the total amount of seamless belts. A more preferable addition amount is 1 to 10% by mass. When the fluorine-based additive is added in an amount of 25% by mass or more, the dispersibility and compatibility of the fluorine-based additive with respect to the POM that is the belt base material is deteriorated, and the belt strength is reduced. Moreover, when it adds more than 25 mass%, many hydrogen fluoride will generate | occur | produce at the time of recycling, and it is unpreferable.

  By making the seamless belt have the material composition according to the present invention as described above, the slip resistance can be reduced to 1.0 N or less, and further to 0.7 N or less, which makes the toner fusion to the seamless belt extremely effective. As a result, toner transfer properties and toner cleaning properties are also improved.

The volume resistance of the seamless belt of the present invention is preferably 100 to 10 ¹² Ω, and more preferably 10 ⁶ to 10 ¹¹ Ω. Further, the surface resistance of the seamless belt of the present invention is preferably 100 to 10 ¹⁷ Ω, and more preferably 10 ⁶ to 10 ¹⁴ Ω.

  Here, in order for the electrophotographic seamless belt of the present invention to sufficiently function as a transfer member of an image forming apparatus, the maximum volume resistance and surface resistance of each part of the belt should be within 10 times the minimum value. Is preferred.

  In particular, the ratio between the maximum value and the minimum value of volume resistance in the circumferential direction of the seamless belt (maximum value of volume resistance / minimum value of volume resistance) is preferably 10 or less. The ratio is more preferably 7 or less. The reason is as follows. If the ratio of the maximum value and the minimum value of the volume resistance in the circumferential direction is larger than 10, transfer unevenness may occur along the circumferential direction of the seamless belt. In addition, when a voltage is applied at a plurality of locations on the seamless belt at the time of transfer, current may flow from a portion where the voltage is applied to another portion where the voltage is applied via a portion having a low resistance in the circumferential direction. is there. As a result, voltage control on the seamless belt is disturbed, and normal operation may not be performed.

  The ratio of the maximum value and the minimum value of the surface resistance in the circumferential direction of the seamless belt (maximum value of surface resistance / minimum value of surface resistance) is preferably 10 or less. This ratio is more preferably 7 or less. The reason is as follows. If the ratio of the maximum value and the minimum value of the surface resistance in the circumferential direction is larger than 10, transfer unevenness may occur along the circumferential direction of the seamless belt. In addition, when a voltage is applied at a plurality of locations on the seamless belt at the time of transfer, current may flow from a portion where the voltage is applied to another portion where the voltage is applied via a portion having a low resistance in the circumferential direction. is there. As a result, voltage control on the seamless belt is disturbed, and normal operation may not be performed.

Moreover, it is preferable that ratio (maximum value of volume resistance / minimum value of volume resistance) of the volume resistance in the direction of the generatrix of the seamless belt is 10 or less. This ratio is more preferably 7 or less. When the ratio of the maximum value and the minimum value of the volume resistance in the bus direction is greater than 10,
This is because there is a risk that uneven transfer occurs along the generatrix direction of the seamless belt, or an excessive current flows into the minimum resistance region, causing the device to malfunction.

  Furthermore, it is preferable that the ratio (maximum value of surface resistance / minimum value of surface resistance) of the maximum value and the minimum value of the surface resistance in the bus direction of the seamless belt is 10 or less. This ratio is more preferably 7 or less. The reason is as follows. If the ratio between the maximum value and the minimum value of the surface resistance in the busbar direction is larger than 10, transfer unevenness may occur along the busbar direction of the seamless belt. In addition, when applied to an image forming apparatus using a cleaning method in which a predetermined charge is applied to the transfer residual toner and returned to the electrophotographic photosensitive member, an excessive current flows from the charging member to which the charge is applied to the surface resistance minimum portion of the seamless belt. In addition, since a sufficient electric field is not applied in the bus direction of the portion, cleaning unevenness may occur in the direction of the seamless belt.

  The volume resistance and the surface resistance in the present invention are not merely a difference in measurement conditions, but show completely different electrical characteristics. That is, when the voltage / current applied to the transfer member is applied in the thickness direction, the movement of the charge of the transfer member is mainly determined by the structure and physical properties inside the transfer member. The static elimination speed is determined. On the other hand, when voltage / current is applied so that charge is transferred only on the surface of the transfer member, the ratio of additives and resistance control agents on the surface is almost independent of the internal structure and layer structure of the transfer member. Charging and static elimination are determined only by. Therefore, when the volume resistance and the surface resistance are in the above range, the transfer efficiency is maintained, the transfer performance of the transfer member is uniform, and the occurrence of defects such as filming is prevented to obtain a good image quality over the entire image. It is preferable from the viewpoint. In the present invention, by making the seamless belt have the material composition according to the present invention, the volume resistance and surface resistance of the seamless belt can be adjusted so as to satisfy the above requirements.

  The thickness of the electrophotographic seamless belt in the present invention is preferably 45 to 300 μm, particularly 50 to 270 μm. According to the material composition according to the present invention, the thickness unevenness in the circumferential direction of the seamless belt can be kept within 15% and even within 10% despite using a POM having a high molding shrinkage rate. As a result, it is possible to suppress variations in the belt peripheral speed and the occurrence of color misregistration resulting therefrom.

  The electrophotographic seamless belt of the present invention may be a single layer composed of a layer containing at least POM and polyether ester amide or polyether amide, and may be a multilayer layer having other layers. There is no particular limitation.

  The method for producing a seamless belt for electrophotography of the present invention is preferably a production method having high production efficiency and capable of suppressing costs. As a method for preferably producing the seamless belt of the present invention, a molding material is continuously melt extruded from an annular die to form a tube, and the obtained tube is cut to a required length to produce a seamless belt, and then seamlessly Examples of the method include processing using a die for the purpose of adjusting the surface smoothness and dimensions of the belt.

  As a method for producing the seamless belt of the present invention, for example, inflation molding is suitably used. Hereinafter, an embodiment of the method for producing the electrophotographic seamless belt of the present invention will be described with reference to FIG. However, it is not limited only to that method.

FIG. 3 is a schematic view showing the configuration of an extrusion molding machine used in the present invention. In FIG. 3, two extruders 100 and 101 are provided for forming a two-layer belt, but at least one extruder may be provided in the present invention. Hereinafter, a method for producing a single-layer seamless belt will be described. First, POM and polyether ester amide or polyether amide, and if necessary, conductive inorganic fine particles, fluorine additives and other materials are premixed in a desired formulation in advance and then kneaded and dispersed to obtain a molding raw material. obtain. The obtained forming raw material is put into a hopper 102 provided in the extruder 100. In the extruder 100, the set temperature and the screw configuration of the extruder are selected so that the forming raw material has a melt viscosity that enables belt forming in a subsequent process, and the raw materials are uniformly dispersed. The forming raw material is melted and kneaded in the extruder 100 to become a melt and enters the annular die 103. The annular die 103 is provided with a gas introduction path 104. When air is blown into the annular die 103 from the gas introduction path 104, the melt that has passed through the annular die 103 expands and expands in the radial direction. The melt may be formed without blowing air into the gas introduction path 104.

The expanded molded body (that is, the tubular melt) is pulled upward while being cooled by the cooling ring 105. By cutting this into a desired width, a seamless belt can be obtained. The extrusion molding ratio in the present invention is the ratio of the diameter in the shape dimension of the tube after molding that has passed through the annular die and expanded in diameter relative to the diameter of the annular die 103, and is represented by the following formula.
Extrusion ratio = Diameter of tube after molding / Diameter of annular die 103

  Although the above description relates to a single-layer belt, when a two-layer seamless belt is manufactured, an extruder 101 is further used as shown in FIG. throw into. The molding material is fed into the two-layer annular die 103 simultaneously with the molding material in the extruder 100, and a two-layer belt can be obtained by expanding and expanding two layers simultaneously. Of course, the same applies to a seamless belt having three or more layers, and an extruder may be prepared corresponding to the number of layers.

  Further, it is preferable that the thickness of the formed seamless belt is made thinner than the die gap of the annular die 103. For example, when trying to make a 150 μm tube with a die gap of 150 μm, when the die gap is moved by 50 μm, the tube changes as it is by 50 μm, but it is difficult to actually adjust the die gap in units of 1 μm. As a result, a tube having a non-uniform film thickness (that is, a seamless belt) can be easily formed. However, for example, when making a 150 μm tube with a die gap of 1.5 mm, even if the die gap is 50 μm, the final film thickness fluctuation is 1/10, so the actual film thickness fluctuation is 5 μm. As a result, the tube can be finally produced with high accuracy. Therefore, it is preferable to reduce the thickness of the molded seamless belt from the die gap of the annular die.

  As a method of reducing the thickness of the formed seamless belt from the die gap of the annular die 103, a method of increasing the tube take-up speed rather than the discharge speed of the tube-like melt discharged from the tip of the annular die by the extruder. There is. For example, the extrusion speed of a tube-like melt extruded without taking out the tube from the tip of the die is 1 m / min, the diameter of the die is the same as the diameter of the formed tube, and the take-up speed is 10 m / min. Sometimes the thickness of the tube becomes 1/10 of the die gap of the annular die, and the thickness of the seamless belt formed from the die gap of the annular die can be reduced.

  Further, as a method of reducing the thickness of the formed belt from the die gap of the annular die, there is a method of making the extrusion molding ratio larger than 1. That is, by making the tube diameter larger than the die diameter, even if the take-off speed is the same as the extrusion speed, the film thickness is reduced by the increase in the tube diameter. The maximum value of the molding ratio at this time is preferably 4.0 or less. If it is larger than this, the stability of the expanded tube may deteriorate, and the film thickness of the resulting seamless belt may become unstable.

  As described above, the thickness of the seamless belt formed from the die gap of the annular die can be reduced by increasing the take-off speed by setting the extrusion molding ratio to 1 or less, but this method is mainly used at the time of molding. It is useful when the molecular weight of the resin (molding raw material) is low.

  That is, when the molding raw material has a low viscosity at the time of melting, if the molding ratio is greater than 1, holes may be formed in the tube. In such a case, by setting the extrusion molding ratio to 1 or less, the thickness of the molded seamless belt can be made thinner than the die gap of the annular die. The minimum value of the molding ratio at this time is preferably 0.5 or more. If it is less than 0.5, it is necessary to greatly increase the tube take-up speed, and the moldability may become unstable.

  Further, as a molding method when the extrusion molding ratio is larger than 1, by blowing a gas having a pressure higher than atmospheric pressure from the gas introduction path 104 into the tubular melt discharged from the tip of the annular die 103 by the extrusion of the extruder. There is a method of continuously forming the tube while expanding the tube. In this case, when the gas of atmospheric pressure or higher is blown into the tube, the tube expands and the extrusion ratio can be made larger than 1. At this time, any gas such as nitrogen, carbon dioxide and argon can be selected as the gas to be blown into the tubular melt.

  Moreover, when the obtained tube is cut into a predetermined width, it is preferable that the tubular film discharged from the extruder from the tip of the annular die is continuously cut in the direction perpendicular to the busbar direction. If cutting is performed with the cutter teeth stopped at the time of cutting, there will be a time difference between the start and end of cutting, and the cutting will be performed diagonally. For this reason, when processing into a belt, it will be necessary to cut again, and man-hours will increase. As a method of continuously cutting the tubular film in the direction perpendicular to the generatrix direction, there is a method using a cutter device that moves at the same speed as the tube extrusion speed, but not limited to this, any method is used. Can do.

  Next, the cylindrical film is processed using a mold for the purpose of adjusting surface smoothness and dimensions. Specifically, there is a method of using a set of cylindrical shapes having different diameters made of materials having different thermal expansion coefficients. The thermal expansion coefficient of the small-diameter cylindrical mold (inner mold) is set to be larger than that of the large-diameter cylindrical mold (outer mold), and the inner mold is covered with a cylindrical film formed on the inner mold. It is inserted into the outer mold, and the cylindrical film is sandwiched between the inner mold and the outer mold. The gap between the molds is calculated in consideration of the difference between the heating temperature, the thermal expansion coefficient between the inner mold and the outer mold, and the required pressure. The mold installed in the order of the inner mold, the cylindrical film, and the outer mold is heated to near the softening point temperature of the resin. By heating, the inner mold having a large coefficient of thermal expansion expands from the outer mold, and a uniform pressure is applied to the entire surface of the tubular film. At this time, the surface of the resin film that has reached the vicinity of the softening point is pressed against the smooth inner surface of the outer mold, and the smoothness of the resin film surface is improved. Then, by cooling and removing the film from the mold, it is possible to obtain a smooth surface property such that the film thickness unevenness is in the above range, for example.

  Further, the surface smoothness of the belt can be adjusted by adjusting the surface roughness of the inner surface of the outer mold. Thereafter, a reinforcing member, a guide member, and a position detection member are attached or precision cut as necessary to obtain an electrophotographic seamless belt.

Hereinafter, an image forming apparatus in which the above-described electrophotographic seamless belt of the present invention is suitably used will be described. FIG. 1 is a schematic view of an example of an image forming apparatus using the seamless belt of the present invention as an intermediate transfer belt. The apparatus shown in FIG. 1 is a color image forming apparatus (copier or laser beam printer) using an electrophotographic process, and has the seamless belt of the present invention as an intermediate transfer belt 5. Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member that is repeatedly used as a first image carrier, and is driven to rotate in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed). The electrophotographic photosensitive member 1 is uniformly charged to a predetermined polarity / potential by the primary charger 2 during the rotation process, and then image exposure means (not shown) (color separation / imaging exposure optical system for color original image, A first color component image of a target color image (for example, a first color component image (for example, scanning exposure system using a laser scanner that outputs a laser beam modulated in accordance with a time-series electric digital pixel signal of image information)) , An electrostatic latent image corresponding to the yellow color component image) is formed. Next, the electrostatic latent image is developed with yellow toner Y, which is a first color developer, by a first developer (yellow developer 41). At this time, the developing units of the second to fourth developing units (magenta color developing unit 42, cyan color developing unit 43 and black color developing unit 44) are turned off and do not act on the electrophotographic photosensitive member 1. The first color yellow toner image is not affected by the second to fourth developing units.

  The intermediate transfer belt 5 is rotationally driven in the clockwise direction in the drawing at the same peripheral speed as the electrophotographic photoreceptor 1. In the process in which the yellow toner image of the first color formed and supported on the electrophotographic photosensitive member 1 passes through the nip portion between the electrophotographic photosensitive member 1 and the intermediate transfer belt 5, the primary transfer roller 6 to the intermediate transfer belt 5. The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5 by the electric field formed by the primary transfer bias applied to the intermediate transfer belt 5. The surface of the electrophotographic photoreceptor 1 that has finished transferring the first color yellow toner image corresponding to the intermediate transfer belt 5 is cleaned by the cleaning device 13.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black toner image are sequentially superimposed and transferred onto the intermediate transfer belt 5, and a composite color corresponding to the target color image is obtained. A toner image is formed. Reference numeral 7 denotes a secondary transfer roller, which is supported in parallel with the secondary transfer counter roller 8 and arranged in a state in which it can be separated from the lower surface portion of the intermediate transfer belt 5. A primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the electrophotographic photosensitive member 1 to the intermediate transfer belt 5 has a polarity (+) opposite to that of the toner, and is applied from a bias power source 30. . The applied voltage is, for example, in the range of +100 V to 2 kV. In the primary transfer process of the first to third color toner images from the electrophotographic photosensitive member 1 to the intermediate transfer belt 5, the secondary transfer roller 7 can be separated from the intermediate transfer belt 5.

  The transfer of the composite color toner image transferred onto the intermediate transfer belt 5 to the transfer material P as the second image carrier is performed as follows. The secondary transfer roller 7 is brought into contact with the intermediate transfer belt 5 and from the paper feed roller 11 through the transfer material guide 10 to a contact nip between the intermediate transfer belt 5 and the secondary transfer roller 7 at a predetermined timing. The transfer material P is fed, and a secondary transfer bias is applied from the power source 31 to the secondary transfer roller 7. The composite color toner image is transferred (secondary transfer) from the intermediate transfer belt 5 to the transfer material P as the second image carrier by the secondary transfer bias.

  The transfer material P that has received the transfer of the toner image is introduced into the fixing device 15 and fixed by heating. After the image transfer to the transfer material P is completed, a cleaning charging member 9 is brought into contact with the intermediate transfer belt 5 and is not transferred to the transfer material P by applying a bias having a polarity opposite to that of the electrophotographic photosensitive member 1. In addition, a charge having a polarity opposite to that of the electrophotographic photoreceptor 1 is applied to the toner (transfer residual toner) remaining on the intermediate transfer belt 5. Reference numeral 33 denotes a bias power source. The transfer residual toner is electrostatically transferred to the electrophotographic photosensitive member 1 at and near the nip portion with the electrophotographic photosensitive member 1, thereby cleaning the intermediate transfer member.

  FIG. 1 is an example of an image forming apparatus using the seamless belt of the present invention as an intermediate belt. However, the seamless belt of the present invention is also preferably used as a transfer conveyance belt of an image forming apparatus as shown below. Can do. FIG. 2 is a schematic view showing an example of an image forming apparatus using the seamless belt of the present invention as a transfer conveyance belt which is one of transfer members.

The image forming apparatus shown in FIG. 2 forms a toner image of a different color on a plurality of photoconductors as a type of color image forming apparatus of the color separation image superposition transfer method, and sequentially contacts these photoconductors. A toner image on each photoconductor is transferred to a single transfer material conveyed in order to obtain a full color image. The image forming apparatus shown in FIG. 2 has four image forming units I, II, III, and IV arranged in parallel as electrophotographic process means.
IV are electrophotographic photoreceptors 301Y, 301M, 301C, and 301BK as image carriers, primary charging rollers 302Y, 302M, 302C, and 302BK as primary chargers, exposure units 303Y, 303M, 303C, and 303BK, and developing units 304Y, 304M, 304C, 304BK, and cleaners 305Y, 305M, 305C, 305BK. The developing devices 304Y, 304M, 304C, and 304BK contain yellow (Y), magenta (M), cyan (C), and black (BK) toners, respectively.

  A transfer device 310 is provided below the image forming units I to IV. The transfer device 310 includes an endless transfer conveyance belt 314 stretched between a driving roller 311, a driven roller 312, and a tension roller 313, electrophotographic photoreceptors 301 </ b> Y, 301 </ b> M, 301 </ b> C of the image forming units I to IV, and It has transfer rollers 315Y, 305M, 305C and 305BK arranged to face 301BK. On the other hand, a cassette (not shown) in which a plurality of recording papers P are stacked and accommodated as a recording medium is installed at the bottom of the apparatus main body, and the recording paper P in the cassette is fed by a paper feed roller 307. Each sheet is fed out and conveyed through a conveyance guide 308. A separation charger 316 and a fixing device 317 are disposed on the downstream side in the transport direction of the recording paper P in the apparatus main body.

  In each of the image forming units I to IV, the electrophotographic photoreceptors 301Y, 301M, 301C, and 301BK are rotationally driven at a predetermined speed in the direction of the arrow in the drawing, and these are respectively rotated by the primary charging rollers 302Y, 302M, 302C, and 302BK. In this way, it is charged. When the exposure light 303Y, 303M, 303C and 303BK corresponding to the image information is irradiated from the exposure unit (not shown) to the electrophotographic photoreceptors 301Y, 301M, 301C and 301BK thus charged, An electrostatic latent image is formed on the surface of each of the photoconductors 301Y, 301M, 301C, and 301BK, and each electrostatic latent image is developed with toner of each color stored in each developing device 304Y, 304M, 304C, and 304BK, and yellow toner. An image, a magenta toner image, a cyan toner image, and a black toner image are visualized.

  On the other hand, the recording paper P as a transfer material conveyed from the cassette through the conveyance guide 308 as described above is sent to the transfer device 310 at the same timing, and is adsorbed to the transfer conveyance belt 314 of the transfer device 310. And moves through the image forming units I to IV, and in the process, the recording paper P is subjected to transfer chargers 315Y, 315M, 315C, and 315BK to cause yellow toner images, magenta toner images, cyan toner images, and black toners. The toner image is transferred in a superimposed manner.

  Then, the recording paper P that has received the transfer of each color toner image is de-charged by the separation charger 316 and separated from the transfer conveyance belt 314, and is then conveyed to the fixing device 317 to be heated and fixed by the color toner image. Is output.

The measuring method of various physical property values used in the present invention is as follows.
<Electrical resistance measurement method>
The electrical resistance (volume resistance and surface resistance) of the electrophotographic seamless belt of the present invention is measured by the following apparatus and conditions.

(Measuring machine)
Resistance meter: Super high resistance meter R8340A (manufactured by Advantest)
Sample box: Sample box TR42 for ultra-high resistance measurement (manufactured by Advantest)
However, the diameter of the main electrode is 25 mm, the inner diameter of the guard ring electrode is 41 mm, and the outer diameter is 49 mm.

(sample)
The intermediate transfer belt is cut into a circle having a diameter of 56 mm. After cutting, an electrode made of a Pt—Pd vapor deposition film is provided on the entire surface of one surface, and a main electrode having a diameter of 25 mm and a guard electrode having an inner diameter of 38 mm and an outer diameter of 50 mm are provided on the other surface. The Pt—Pd vapor deposition film can be obtained by performing a vapor deposition operation for 2 minutes with mild sputtering E1030 (manufactured by Hitachi, Ltd.). The sample after the vapor deposition operation is used as a measurement sample.

(Measurement condition)
Measurement atmosphere: 23 ° C., 55% RH. The measurement sample is previously left in an atmosphere of 23 ° C. and 55% RH for 12 hours or more.
Measurement mode: Program mode 5 (discharge 10 seconds, charge and major 30 seconds)
Applied voltage: 100 (V)

<Slip resistance measurement method>
The dynamic frictional resistance of the electrophotographic seamless belt of the present invention is represented by the sliding resistance of the sample sheet to the polyethylene terephthalate (PET) sheet by the electrophotographic seamless belt of the present invention. Specifically, it is obtained by measuring using a surface property measuring instrument: HEIDON-14DR (manufactured by Shinbun Kagaku Co., Ltd.). Specifically, a polyethylene terephthalate (PET) sheet is wound around a flat indenter specified in ASTM D-1894 of HEIDON-14DR to make a measurement object, and a vertical load of 2N is applied between the sample sheet and the flat indenter to 100 mm / horizontal direction. min. It is obtained by measuring the slip resistance between the PET sheet and the sample sheet when the sample sheet is moved at a speed of.

<Thickness measurement method>
The film thickness of the intermediate transfer belt of the present invention is a value obtained by measuring and averaging over the entire circumference of 40 points at equal intervals in the circumferential direction with respect to the center of the belt in a dial gauge having a minimum value of 1 μm. Further, the difference between the maximum value and the average value of the film thickness and the difference between the minimum value and the average value are defined as film thickness unevenness.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited only to these Examples.
<Example 1>
(raw materials)
Polyacetal (POM) 84 parts Polyetheresteramide 15 parts (Pelestat NC6321 manufactured by Sanyo Chemical Industries)
1 part of acetylene black (Denka Black powder product manufactured by Denki Kagaku Kogyo Co., Ltd.)

(Kneading equipment and kneading conditions)
・ Uses a 30mm diameter same-direction rotary meshing twin screw extruder ・ Screw: Double type, L / D = 38
Extrusion temperature: 180 ° C
Extrusion conditions: Screw rotation 200rpm, discharge rate 15kg / h
The raw materials were mixed with a tumbler, and then kneaded under the above conditions using the biaxial extrusion kneader to obtain a kneaded product having a particle diameter of 2 to 3 mm, whereby a molding raw material 1 was obtained.

(Molding)
The raw material 1 for shaping | molding was thrown into the hopper 102 of the single screw extruder 100 shown in FIG. 3, and it was set as the set temperature in the range of 175-185 degreeC, and it was set as the melt. Subsequently, the melt was introduced into an annular single layer extrusion die 103 having a die diameter of 100 mm and a die gap width of 80 μm. At this time, the discharge speed of the tubular melt discharged from the tip of the die was 1 m / min. Air was blown into the melt from the gas introduction path 104 to expand and expand the melt, and while forming at a take-up speed of 5 m / min, forming a tubular film continuously in a direction perpendicular to the generatrix direction every 300 mm. The seamless belt 1 was obtained by cutting it. The extrusion molding ratio at this time was 1.6.

  The size and surface smoothness of the seamless belt 1 were adjusted using a set of cylindrical shapes made of metals having different coefficients of thermal expansion. An aluminum material having a high thermal expansion coefficient was used for the inner mold, and stainless steel having a lower thermal expansion coefficient than aluminum was used for the outer mold. The outer mold was buffed on the inner surface and finished to a mirror surface. The dimensional gap between the outer diameter of the inner mold and the inner diameter of the outer mold was 140 μm. The tubular film 1 is placed on an inner mold having a high coefficient of thermal expansion, the inner mold is inserted into the outer mold, and heated at 170 ° C. for 20 minutes. After cooling, it was removed from the cylinder, the end was cut, a meandering prevention member was attached, and a black seal was affixed as a position detection member to produce an intermediate transfer belt 1 having a diameter of 160 mm. When ten intermediate transfer belts were subsequently produced by the same method, the intermediate transfer belt could be produced satisfactorily without problems such as mold sticking.

(Evaluation)
In the intermediate transfer belt 1, as shown in FIG. 4, the volume resistance and the surface resistance at four locations in the circumferential direction and two locations in the axial direction at each position, a total of eight locations, and their variations were measured. The value is 3.2 × 10 ¹⁰ Ω, the median surface resistance is 2.5 × 10 ¹¹ Ω, the maximum / minimum value of volume resistance is 1.5, and the maximum / minimum value of surface resistance is 1.7. there were. Moreover, the slip resistance was 0.3N. Further, the variation in film thickness measurement was in the range of 100 μm ± 8 μm.

The intermediate transfer belt 1 is mounted on the full-color image forming apparatus shown in FIG. 1, and a secondary color full-color solid image and a halftone image are printed on 80 g / m ² paper using a commercially available toner. Sexuality was evaluated. The cleaning method of the intermediate transfer belt was a primary transfer simultaneous cleaning method using an elastic roller having a resistance of 1 × 10 ⁸ Ω for the cleaning charging member 7. As a result, it was possible to obtain a good image without occurrence of uneven transfer and transfer omission and no defective cleaning. Further, when 50,000 images were output using this intermediate transfer belt 1, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Example 2>
Polyacetal (POM) 80 parts Polyetheresteramide 15 parts (Pelestat NC6321 manufactured by Sanyo Chemical Industries)
5 parts of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo Co., Ltd.)
An intermediate transfer belt 2 was produced in the same manner as in Example 1 except that the raw materials were as described above. Moreover, when the belt physical properties were evaluated in the same manner as in Example 1, the median value of the volume resistance was 7.8 × 10 ⁹ Ω, the median value of the surface resistance was 1.1 × 10 ¹¹ Ω, and the maximum value of the volume resistance. The minimum value was 1.8, the maximum / minimum value of the surface resistance was 2.0, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 8 μm.

  Further, when the intermediate transfer belt 2 was used to output an image, it was possible to obtain a good image without occurrence of uneven transfer and transfer omission, and without defective cleaning. Further, when 50,000 images were output using the intermediate transfer belt 2, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Example 3>
Polyacetal (POM) 74 parts Polyetheresteramide 16 parts (Ciba Specialty Chemicals IRGASTAT P18)
10 parts of conductive zinc oxide An intermediate transfer belt 3 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt properties were evaluated in the same manner as in Example 1, the median value of volume resistance was 8.2 × 10 ⁹ Ω, the median value of surface resistance was 9.9 × 10 ¹⁰ Ω, and the maximum value of volume resistance. / The minimum value was 1.7, the maximum value / minimum value of the surface resistance was 2.0, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 7 μm.

  Further, when the intermediate transfer belt 3 was used to output an image, a good image with no transfer unevenness, no transfer omission, and no cleaning failure could be obtained. Further, when 50,000 images were output using the intermediate transfer belt 3, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Example 4>
Polyacetal (POM) 74 parts Polyetheresteramide 6 parts (Ciba Specialty Chemicals IRGASTAT P16)
5 parts of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo Co., Ltd.)
Conductive zinc oxide 15 parts (23-K by Hakusuitec)
An intermediate transfer belt 4 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt physical properties were evaluated in the same manner as in Example 1, the median value of volume resistance was 6.6 × 10 ⁹ Ω, the median value of surface resistance was 7.7 × 10 ¹⁰ Ω, and the maximum value of volume resistance. The minimum value was 7.4, the maximum value / minimum value of the surface resistance was 5.0, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 10 μm.

  Further, when the intermediate transfer belt 4 was used to output an image, it was possible to obtain a good image with no occurrence of uneven transfer and transfer omission and no cleaning failure. Furthermore, when 50,000 sheets of images were output using this intermediate transfer belt 4, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Example 5>
Polyacetal (POM) 65 parts Polyetheresteramide 20 parts (Pelestat NC6321 manufactured by Sanyo Chemical Industries)
10 parts of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo Co., Ltd.)
PTFE particles 5 parts (KTL-2N manufactured by Kitamura)
An intermediate transfer belt 5 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt physical properties were evaluated in the same manner as in Example 1, the median volume resistance was 4.3 × 10 ⁸ Ω, the median surface resistance was 3.6 × 10 ⁹ Ω, and the maximum volume resistance value. The minimum value was 2.5, the maximum / minimum value of the surface resistance was 2.1, the slip resistance was 0.4 N, and the variation in film thickness measurement was in the range of 100 μm ± 6 μm.

  Further, when the intermediate transfer belt 5 was used to output an image, a good image with no transfer unevenness, no transfer omission, and no defective cleaning could be obtained. Further, when 50,000 sheets of images were output using the intermediate transfer belt 5, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Example 6>
Polyacetal (POM) 55 parts Polyetheresteramide 24 parts (Ciba Specialty Chemicals P22)
1 part of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo Co., Ltd.)
20 parts of PTFE particles (KTL-8N manufactured by Kitamura)
An intermediate transfer belt 6 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt physical properties were evaluated in the same manner as in Example 1, the median volume resistance was 6.9 × 10 ⁹ Ω, the median surface resistance was 5.9 × 10 ¹⁰ Ω, and the maximum volume resistance value. The minimum value was 2.2, the maximum / minimum value of the surface resistance was 2.4, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 8 μm.

  Further, when the intermediate transfer belt 6 was used to output an image, it was possible to obtain a good image with no occurrence of uneven transfer or transfer omission and no defective cleaning. Further, when 50,000 images were output using the intermediate transfer belt 6, it was found that the belt was excellent in durability without cracking or tearing of the belt.

(Example 7)
Polyacetal (POM) 55 parts Polyetheresteramide 5 parts (IRGASTAT P20 manufactured by Ciba Specialty Chemicals)
15 parts of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo)
20 parts of conductive zinc oxide (23-K, manufactured by Hakusuitec)
An intermediate transfer belt 7 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt properties were evaluated in the same manner as in Example 1, the median value of volume resistance was 3.5 × 10 ⁹ Ω, the median value of surface resistance was 4.5 × 10 ¹¹ Ω, and the maximum value of volume resistance. The minimum value was 8.3, the maximum value / minimum value of the surface resistance was 9.5, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 11 μm.

  Further, when the intermediate transfer belt 7 was used to output an image, it was possible to obtain a good image without occurrence of uneven transfer and transfer omission, and without defective cleaning. Furthermore, when 50,000 images were output using this intermediate transfer belt 7, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Example 8>
Polyacetal (POM) 50 parts Polyetheresteramide 20 parts (Sanyo Chemical Industries Perestat NC6321)
5 parts of conductive zinc oxide (23-K, manufactured by Hakusuitec)
25 parts of PTFE particles (KTL-10N manufactured by Kitamura)
An intermediate transfer belt 8 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt physical properties were evaluated in the same manner as in Example 1, the median value of the volume resistance was 7.7 × 10 ⁹ Ω, the median value of the surface resistance was 4.9 × 10 ¹⁰ Ω, and the maximum value of the volume resistance. / The minimum value was 3.3, the maximum value / minimum value of the surface resistance was 4.5, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 9 μm.

  Further, when the intermediate transfer belt 8 was used to output an image, it was possible to obtain a good image without occurrence of uneven transfer and transfer omission, and without defective cleaning. Further, when 50,000 images were output using the intermediate transfer belt 8, it was found that the belt was excellent in durability without cracking or tearing of the belt.

<Comparative example 1>
(raw materials)
Polycarbonate 85 parts Polyetheresteramide 15 parts (Sanyo Perestat NC6321)

(Kneading equipment and kneading conditions)
A forming raw material 9 was produced in the same manner as in Example 1 except that the extrusion temperature was 240 ° C.

(Molding)
An intermediate transfer belt 9 was produced in the same manner as in Example 1 except that the set temperature at the time of extrusion of the single screw extruder was 240 ° C. and the set temperature at the time of thermoforming with a cylindrical mold was 240 ° C. A total of 10 intermediate transfer belts were produced in the same manner as above, and 5 out of 10 belts were stuck on the mold.

When the belt physical properties were evaluated in the same manner as in Example 1, the median value of volume resistance was 4.3 × 10 ¹⁰ Ω, the median value of surface resistance was 1.3 × 10 ¹¹ Ω, and the maximum value / minimum value of volume resistance. The value was 1.9, the maximum / minimum value of the surface resistance was 2.2, the slip resistance was 0.3 N, and the variation in film thickness measurement was in the range of 100 μm ± 7 μm.

  Further, when an image was output using the intermediate transfer belt 9, transfer unevenness, transfer omission occurred, and cleaning failure occurred. Further, when 50,000 images were output using the intermediate transfer belt 9, cracks occurred in the belt.

<Comparative example 2>
Polyacetal (POM) 90 parts Carbon black 10 parts (Denka Black powder product manufactured by Denki Kagaku Kogyo)
An intermediate transfer belt 10 was produced in the same manner as in Example 1 except that the raw materials were as described above. Moreover, when the belt physical properties were evaluated in the same manner as in Example 1, the median value of the volume resistance was 2.2 × 1.
0 ¹⁰ Ω, median surface resistance is 9.8 × 10 ¹⁰ Ω, maximum / minimum value of volume resistance is 10.1, maximum / minimum value of surface resistance is 12.0, and slip resistance is 0 .3N, variation in film thickness measurement was in the range of 100 μm ± 16 μm.

  Further, when an image was output using the intermediate transfer belt 10, transfer defects such as roughness and transfer unevenness occurred. In addition, due to transfer failure, cleaning failure also occurred. Further, when 50,000 images were output using this intermediate transfer belt 10, no cracking or tearing of the belt occurred.

<Comparative Example 3>
Polyacetal (POM) 80 parts Thermoplastic polyurethane 10 parts (Kuraray Kuramylon U1180)
10 parts of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo Co., Ltd.)
An intermediate transfer belt 11 was produced in the same manner as in Example 1 except that the raw materials were as described above. Moreover, when the belt physical properties were evaluated in the same manner as in Example 1, the median value of the volume resistance was 8.9 × 10 ⁹ Ω, the median value of the surface resistance was 1.1 × 10 ¹¹ Ω, and the maximum value of the volume resistance. The minimum value was 11.0, the maximum value / minimum value of the surface resistance was 10.2, the slip resistance was 0.6 N, and the variation in film thickness measurement was in the range of 100 μm ± 17 μm.

  Further, when an image was output using the intermediate transfer belt 11, transfer defects such as roughness and transfer unevenness occurred. In addition, due to transfer failure, cleaning failure also occurred. Further, when 50,000 images were output using the intermediate transfer belt 11, no cracking or tearing of the belt occurred.

<Comparative example 4>
Polyacetal (POM) 70 parts Polyester elastomer 15 parts (Hytorel 5557 manufactured by Toray DuPont)
15 parts of carbon black (Denka Black powder product manufactured by Denki Kagaku Kogyo)
An intermediate transfer belt 12 was produced in the same manner as in Example 1 except that the raw materials were as described above. In addition, when the belt physical properties were evaluated in the same manner as in Example 1, the median volume resistance was 6.5 × 10 ⁹ Ω, the median surface resistance was 5.6 × 10 ¹⁰ Ω, and the maximum volume resistance value. The minimum value was 13.0, the maximum value / minimum value of the surface resistance was 11.5, the slip resistance was 0.6 N, and the variation in film thickness measurement was in the range of 100 μm ± 15 μm.

  Further, when an image was output using the intermediate transfer belt 12, transfer defects such as roughness and transfer unevenness occurred. In addition, due to transfer failure, cleaning failure also occurred. Further, when 50,000 sheets of images were output using the intermediate transfer belt 12, no cracking or tearing of the belt occurred.

<Comparative Example 5>
Polyacetal (POM) 80 parts Carbon black 10 parts (Denka Black powder product manufactured by Denki Kagaku Kogyo)
10 parts of polyethylene oxide (ZSN8100 manufactured by Nippon Zeon)
An intermediate transfer belt 13 was produced in the same manner as in Example 1 except that the raw materials were as described above. Further, when the belt physical properties were evaluated in the same manner as in Example 1, the median value of the volume resistance was 5.8 × 10 ⁹ Ω, the median value of the surface resistance was 6.9 × 10 ¹⁰ Ω, and the maximum value of the volume resistance. / The minimum value was 10.5, the maximum value / minimum value of the surface resistance was 13.0, the slip resistance was 0.7 N, and the variation in film thickness measurement was in the range of 100 μm ± 18 μm.

  Further, when an image was output using the intermediate transfer belt 13, transfer defects such as roughness and transfer unevenness occurred. In addition, due to transfer failure, cleaning failure also occurred. Further, when 50,000 images were output using the intermediate transfer belt 13, no cracking or tearing of the belt occurred.

Schematic of an example of an image forming apparatus provided with the intermediate transfer belt of the present invention Schematic of an example of an image forming apparatus provided with the transfer conveyance belt of the present invention Schematic of an example of an extrusion machine used in the present invention The figure which shows an example of the measurement part of the electrical resistance of a seamless belt

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Primary charging machine 3 Exposure light 5 Intermediate transfer belt 6 Primary transfer roller 7 Secondary transfer roller 8 Secondary transfer counter roller 9 Cleaning charging member 10 Transfer material guide 11 Paper feed roller 12 Tension roller 13 Cleaning device DESCRIPTION OF SYMBOLS 15 Fixing device 30, 31, 32, 33 Power supply 41 Yellow color developing device 42 Magenta color developing device 43 Cyan color developing device 44 Black color developing device 100, 101 Extruder 102 Hopper 103 Annular die 104 Gas introduction path 105 External cooling ring 106 Stabilizing plate 107 Pinch roller 108 Cutting device 110 Cylindrical film 301Y, 301M, 301C, 301BK Electrophotographic photosensitive member 302Y, 302M, 302C, 302BK Primary charger 303Y, 303M, 303C, 303BK Exposure 304Y, 304M, 304C, 304BK Developer 305Y, 305M, 305C, 305BK Cleaning means 307 Paper feed roller 308 Transport guide 310 Transfer device 311 Drive roller 312 Driven roller 313 Tension roller 314 Transfer transport belt 315Y, 315M, 315C, 315BK Transfer charge 316 Separation charger 317 Fixing device 320Y, 320M, 320C, 320BK Power supply P Transfer material

Claims (18)

A seamless belt for electrophotography, comprising at least 30 to 90% by mass of a polyacetal resin and 1 to 35% by mass of a polyetheresteramide or polyetheramide. The electrophotographic seamless belt according to claim 1, comprising 30 to 74% by mass of the polyacetal resin. The electrophotographic seamless belt according to claim 1 or 2, further comprising 1 to 30% by mass of conductive inorganic fine particles. The electrophotographic seamless belt according to any one of claims 1 to 3, further comprising 0 to 25 mass% of a fluorine-based additive. 5. The electrophotographic seamless belt according to claim 1, wherein a slip resistance is 1.0 N or less. 6. The electron according to claim 1, wherein a ratio between a maximum value and a minimum value of volume resistance in the circumferential direction (maximum value of volume resistance / minimum value of volume resistance) is 10 or less. Seamless belt for photography. 7. The electron according to claim 1, wherein a ratio of a maximum value and a minimum value of the surface resistance in the circumferential direction (maximum value of surface resistance / minimum value of surface resistance) is 10 or less. Seamless belt for photography. 8. The electron according to claim 1, wherein a ratio between a maximum value and a minimum value of volume resistance in the busbar direction (maximum value of volume resistance / minimum value of volume resistance) is 10 or less. Seamless belt for photography. 9. The electron according to claim 1, wherein a ratio between a maximum value and a minimum value of the surface resistance in the busbar direction (maximum value of surface resistance / minimum value of surface resistance) is 10 or less. Seamless belt for photography. The seamless belt for electrophotography according to any one of claims 1 to 9, wherein film thickness unevenness in a circumferential direction is within 15%. At least, a molding raw material containing 30 to 90% by mass of a polyacetal resin and 1 to 35% by mass of a polyether ester amide or a polyether amide is obtained,
The raw material for molding is melt-extruded from an annular die to obtain a tubular melt,
Forming a tube by drawing the tube-like melt at a predetermined take-up speed while cooling,
A method for producing a seamless belt for electrophotography, wherein the tube is cut to obtain a seamless belt. 12. The method for producing a seamless belt for electrophotography according to claim 11, wherein the tube is thinner than the die gap of the annular die. The method for producing a seamless belt for electrophotography according to claim 11 or 12, wherein the take-up speed is faster than a discharge speed of a tube-like melt that is pushed out from the annular die and discharged. The method for producing a seamless belt for electrophotography according to any one of claims 11 to 13, wherein an extrusion molding ratio of the tube is set to 0.5 to 4.0. Forming a tube by inflating the melt by blowing a gas at atmospheric pressure or higher into the inside of a tube-shaped melt obtained by melt extrusion from the annular die, and taking it out while cooling it. The method for producing a seamless belt for electrophotography according to any one of claims 11 to 14, characterized in that: The method for producing a seamless belt for electrophotography according to any one of claims 11 to 15, wherein a seamless belt is obtained by continuously cutting the tube after the take-up in a direction perpendicular to the bus bar. . An image forming apparatus for forming an image by visualizing an electrostatic latent image formed on an image carrier with a developer, transferring the image onto a transfer material, and fixing the image. An image forming apparatus comprising the seamless belt for electrophotography described in 1. The image forming apparatus according to claim 17, wherein the seamless belt is used as an intermediate transfer belt and / or a transfer conveyance belt.

Images