JP2003316097A - Endless belt member and electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt member by which a uniform and homogeneous image free from a white spot or central blanking or the like is obtained in image forming by an electrophotographic device having an electrifying means, an image exposure means, a developing means and a transfer means, whose belt is not cracked or ruptured at the traveling time of the belt, which is stably rotated, which has a small number of stages, and which is inexpensive and has high dimensional accuracy, and to provide an electrophotographic device using the endless belt member. <P>SOLUTION: The endless belt member is constituted of resin composition where at least thermoplastic resin and conductivity imparting material are blended, and the maximum value/the minimum value of the surface resistance of each part of the endless belt member is ≤100, and the deflection of inner peripheral length in a longitudinal direction is within ±1.5 mm, and the number of bending times until it is ruptured in a bending fatigue test is equal to or above 5000 times. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endless belt member used in an electrophotographic apparatus having a charging unit, an image exposing unit, a developing unit and a transferring unit, and an electrophotographic apparatus having the member, and more particularly to an intermediate transfer belt and a transfer unit. The present invention relates to a conveyor belt or a photoconductor belt and an electrophotographic apparatus having the member.

[0002]

2. Description of the Related Art An intermediate transfer belt or a transfer / transport belt having an endless belt shape is widely used in image forming apparatuses. For example, an image forming apparatus using an intermediate transfer belt is a color for outputting an image formed product in which a plurality of component color images of color image information and multicolor image information are sequentially laminated and transferred to synthesize and reproduce a color image or a multicolor image. It is effective as an electrophotographic apparatus, a multicolor image forming apparatus, or an image forming apparatus having a color image forming function or a multicolor image forming function.

FIG. 1 is a schematic view showing an example of an electrophotographic apparatus using an intermediate transfer belt.

FIG. 1 shows a color electrophotographic apparatus (copier or laser beam printer) utilizing an electrophotographic process. A resin film having a medium resistance is used for the intermediate transfer belt 20. Reference numeral 1 denotes a rotary drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) which is repeatedly used as a first image bearing member, and is rotationally driven in a clockwise direction indicated by an arrow at a predetermined peripheral speed (process speed). . The photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the primary charger 2 in the course of rotation, and then the image exposure means 3 (color separation / imaging exposure optical system for color original image, A first color component image (for example, yellow) of a target color image by being subjected to image exposure by a scanning exposure system by a laser scanner that outputs a laser beam modulated corresponding to a time-series electric digital pixel signal of image information. An electrostatic latent image corresponding to the color component image) is formed. Next, the electrostatic latent image is developed by the first developing device (yellow developing device 41) with the yellow toner Y which is the first color. 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 in the operation-off state and do not act on the photosensitive drum 1,
The first color yellow toner image is not affected by the second to fourth developing devices. The intermediate transfer belt 20 is rotationally driven in the clockwise direction at the same peripheral speed as the photosensitive drum 1. While the first color yellow toner image formed and carried on the photosensitive drum 1 passes through the nip portion between the photosensitive drum 1 and the intermediate transfer belt 20, the primary transfer roller 6
The intermediate transfer (primary transfer) is sequentially performed on the outer peripheral surface of the intermediate transfer belt 20 by the electric field formed by the primary transfer bias applied to the intermediate transfer belt 20 from 2. The surface of the photosensitive drum 1 which has finished transferring the yellow toner image of the first color corresponding to the intermediate transfer belt 20 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 transferred onto the intermediate transfer belt 20 in an overlapping manner to form a composite color image corresponding to the target color image. A toner image is formed. Reference numeral 61 is a tension roller.
Reference numeral 63 denotes a secondary transfer roller, which corresponds to the secondary transfer counter roller 64 and is supported in parallel to the lower surface of the intermediate transfer belt 20 so as to be separated therefrom. The primary transfer bias for sequentially superposing and transferring the toner images of the first to fourth colors from the photosensitive drum 1 to the intermediate transfer belt 20 is applied from the bias power supply 29 with the polarity (+) opposite to that of the toner. The applied voltage is, for example, in the range of + 100V to 2kV. In the primary transfer process of the toner images of the first to third colors from the photosensitive drum 1 to the intermediate transfer belt 20, the secondary transfer roller 63 can be separated from the intermediate transfer belt 20. The transfer of the composite color toner image transferred onto the intermediate transfer belt 20 onto the transfer material P that is the second image carrier is performed while the secondary transfer roller 63 is in contact with the intermediate transfer belt 20.
The transfer material P is fed from the paper feed roller 11 through the transfer material guide 10 to the contact nip between the intermediate transfer belt 20 and the secondary transfer roller 63 at a predetermined timing, and the secondary transfer bias is supplied from the power supply 28 to 2 It is applied to the next transfer roller 63. The secondary transfer bias causes the secondary transfer bias from the intermediate transfer belt 20 to the second position.
The composite color toner image is transferred (secondary transfer) onto the transfer material P which is the image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing device 15 and is heated and fixed. After the image transfer onto the transfer material P is completed, the cleaning charging member 8 is brought into contact with the intermediate transfer belt 20, and a bias having a polarity opposite to that of the photosensitive drum 1 is applied, so that the intermediate transfer is performed without being transferred to the transfer material P. A charge having a polarity opposite to that of the photosensitive drum 1 is applied to the toner (transfer residual toner) remaining on the belt 20. 26 is a bias power supply. The transfer residual toner is
The intermediate transfer belt is cleaned by being electrostatically transferred to the photosensitive drum 1 at and near the nip portion with the photosensitive drum 1. On the other hand, FIG. 2 shows an example in which the endless belt is used as a transfer / conveying belt in a color electrophotographic apparatus. The transfer material P is adsorbed by the transfer / transport belt 12 and transferred to the fixing device 15 after transferring each color.

A color electrophotographic apparatus using these endless belts as an intermediate transfer belt, a transfer / conveying belt or a photoconductor belt is designed by the flexibility of the belt shape as compared with the case where a rigid body typified by a drum is used. The degree of freedom above is increased, which is greatly advantageous in terms of equipment cost and space saving. Further, since the nip width in the transfer can be widened, the process speed can be set high. Due to these advantages, color copiers and color printers using the endless belt as an intermediate transfer belt, a transfer / conveying belt or a photoconductor belt are operating in the market.

Various characteristics are required for an endless belt used in an electrophotographic apparatus. First, the electric resistance is precisely controlled, and the unevenness of the electric resistance is small in each part of the belt. Second, it has excellent dimensional accuracy for stable rotation and high-quality images. Third, the pulley. It is mechanically strong enough to withstand rotation while being stretched over.

Although various inventions have already been disclosed with respect to the manufacturing method of the endless belt used in these electrophotographic apparatuses, the one satisfying all the above characteristics has not been obtained yet. For example, Japanese Patent Laid-Open No. 2592000 and Japanese Patent Laid-Open No. 4-255332 disclose a method for manufacturing a belt obtained by dispersing conductive carbon black mainly containing polycarbonate as a thermoplastic resin. However, polycarbonate lacks mechanical strength when continuing to stretch and rotate the belt, that is, it is brittle against continuous bending while receiving tension, and depending on the tension state and the number of rotations,
The belt surface may be cracked or even broken. JP-A-6-130830, JP-A-10-83122
As described above, the disclosure of the invention focusing on the tensile elastic modulus as the mechanical strength is conventionally found, but the disclosure of the invention focusing on the strength against continuous bending while receiving the tension as described here. There is no. Further, it is difficult to disperse the carbon black into the primary particles by simply dispersing the carbon black in the polycarbonate, and since secondary aggregation is likely to occur, uneven electrical resistance is likely to occur in the belt, and the electrophotographic apparatus Performance and quality stability as a belt for a car. That is, it may cause troubles such as transfer defects such as white spots and voids in the image, and paper conveyance defects.

On the other hand, various methods for manufacturing endless belts are already known. For example, JP-A-10-63
Japanese Unexamined Patent Publication No. 115 and Japanese Unexamined Patent Publication (Kokai) No. 5-269849 disclose a method of joining sheets to form a cylindrical shape and obtaining a belt. Further, JP-A-9-269674 discloses a method of obtaining a belt by forming a multilayer coating film on a cylindrical substrate and finally removing the substrate.
Further, JP-A-5-77252 discloses a seamless belt formed by a centrifugal molding method. Each of these manufacturing methods has the following drawbacks. That is, in the method of joining sheets, there is a problem in that a step between joints and a decrease in tensile strength are caused. The method of using a solvent such as cast molding, coating or centrifugal molding requires many steps because of the steps of manufacturing a coating liquid-coating-molding-removing the solvent, and is costly. Furthermore, there are problems that affect the environment such as solvent recovery.

[0009]

The inventors of the present invention propose an endless belt member and an electrophotographic apparatus having the member, which solves the above-mentioned problems.

Therefore, an object of the present invention is to form an image by an electrophotographic apparatus having a charging means, an image exposing means, a developing means and a transferring means, especially when it is used as a transfer conveying belt, an intermediate transfer belt or a photosensitive belt. SUMMARY OF THE INVENTION It is an object of the present invention to provide an endless belt member that is uniformly and sufficiently controlled in resistance so as to achieve uniform and uniform image quality without white spots, hollows and the like, and an electrophotographic apparatus having the member. It is another object of the present invention to provide an endless belt member that does not crack or break when the belt is running and can realize stable rotation, and an electrophotographic apparatus having the member. Another object of the present invention is to provide an endless belt member having a small number of steps, low cost, and high dimensional accuracy, and an electrophotographic apparatus having the member.

[0011]

That is, the present invention provides a charging means for applying an electric charge to an electrophotographic photoreceptor, an image exposing means for forming an electrostatic latent image on the electrophotographic photoreceptor, and an electrostatic latent image. Developing means for forming a visible image by developing with toner,
And an endless belt member used in an electrophotographic apparatus having a transfer unit that transfers a toner image to a transfer material,
The endless belt member is made of a resin composition containing at least a thermoplastic resin and a conductivity-imparting material, and the maximum / minimum value of the surface resistance of each part of the endless belt member is 100 times or less, and the internal length in the longitudinal direction is less than 100 times. The endless belt member is characterized in that the deflection of the circumferential length is within ± 1.5 mm, and the number of times of bending before breaking in a bending fatigue test is 5000 times or more.

Further, the present invention is an endless belt member which is an intermediate transfer belt, a transfer conveyance belt or a photoconductor belt.

Further, according to the present invention, charging means for imparting electric charge to the electrophotographic photosensitive member, image exposing means for forming an electrostatic latent image on the electrophotographic photosensitive member, and developing the electrostatic latent image with toner are carried out. An electrophotographic apparatus having a developing means for forming a visible image and a transfer means for transferring a toner image onto a transfer material, the electrophotographic apparatus comprising the endless belt member.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the number of times of bending of an endless belt before breaking in a bending fatigue test is 5000 times or more, preferably 20000 times or more.

The conditions of the bending fatigue test in the present invention are as described below.

<Measuring device> MIT type anti-fatigue tester

<Size of test piece> Width: 15.0mm Length: 110mm Thickness: Same thickness as the endless belt obtained

<Measurement conditions> Bending angle: 135 degrees left and right Bending speed: 175 cpm Load: 4.9 N The method for measuring the surface resistance in the present invention is as described below.

<Measuring machine> Resistance meter: Ultra-high resistance meter R8340A (manufactured by Advantest) Sample box: Ultra-high resistance measurement sample box TR42 (manufactured by Advantest, main electrode diameter 25 mm, guard ring inner diameter 41 m)
m, outer diameter of guard ring 49 mm)

<Sample> The belt is cut into a circle having a diameter of 56 mm. After cutting, one side was provided with an electrode by a Pt-Pd vapor deposition film on the entire surface, and the other surface was provided by a Pt-Pd vapor deposition film with a main electrode having a diameter of 25 mm, an inner diameter of 38 mm, and an outer diameter of 50 mm.
A mm guard electrode is provided. The Pt-Pd vapor deposition film is obtained by performing vapor deposition operation for 2 minutes with mild sputter E1030 (manufactured by Hitachi Ltd.). A sample for which the vapor deposition operation has been completed is used as a measurement sample.

<Measurement conditions> Measurement atmosphere: 23 ° C./55% RH. The measurement sample is left in the atmosphere of 23 ° C./55% RH for 12 hours or more in advance.

Measurement mode: Program mode 5 (discharge 10 seconds, charge and measure 30 seconds) Applied voltage: 1-1000 (V)

The applied voltage can be arbitrarily selected from 1 to 1000V. Further, the applied voltage can be appropriately changed within the range of the applied voltage according to the resistance value, thickness, dielectric breakdown strength, etc. of the sample. Further, if the surface resistances at a plurality of predetermined positions measured at any one of the applied voltages are included in the resistance range of the present invention, it is determined that the resistance range is the object of the present invention.

When the maximum value / minimum value of the surface resistance exceeds 100 times, uneven transfer occurs, or when a voltage is applied at a plurality of points, the voltage is applied from some points to other points. A current may flow into a portion via a portion having a low resistance, and disturbing the voltage control at another portion may prevent normal operation. Further, the volume resistance value of the endless belt is preferably in the range of 1 × 10 ⁰ to 1 × 10 ¹⁴ Ω, and more preferably in the range of 1 × 10 ³ to 1 × 10 ¹² Ω.

Further, the runout of the inner peripheral length in the longitudinal direction of the endless belt (the runout value obtained by measuring at a plurality of predetermined points in the direction perpendicular to the longitudinal direction) The runout is within ± 1.5 mm, preferably ± It is within 1.0 mm. Inner circumference runout in the longitudinal direction of the endless belt is ± 1.5 m
If it is not within m, the transfer efficiency becomes non-uniform within the image and the image quality deteriorates. Further, the rotation of the belt becomes unstable, which causes meandering and derailment.

Regarding the thickness of the endless belt, the runout at each part of the belt is preferably within ± 5.0%, more preferably within ± 3.0%. Unless the thickness fluctuation of the endless belt is within ± 5.0%,
For example, when the endless belt is pressed against the transfer roller and the bias roller, the pressing force may not be uniform and unevenness may occur on the image.

The inner circumferential length in the present invention was measured by cutting the belt into eight equal parts in a direction perpendicular to the longitudinal direction of the endless belt and applying a ruler to the inner circumferential length of each cut portion. The thickness is 4 in the circumferential direction of the endless belt.
Thickness was measured at 16 points, 4 points in the longitudinal direction, using a dial gauge.

As described above, the endless belt according to the present invention is composed of at least the thermoplastic resin and the conductivity-imparting material, which are 6000 times or more before breaking in the bending fatigue test. Specifically as a thermoplastic resin,
Polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-
Vinyl chloride copolymer, styrene-vinyl acetate copolymer,
Styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-
Butyl acrylate copolymer, styrene-octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer,
(Styrene-methyl methacrylate copolymer, styrene-
Styrenic resins such as ethyl methacrylate copolymer and styrene-phenyl methacrylate copolymer), styrene-α-chloromethyl acrylate copolymer, styrene-acrylonitrile-acrylic ester copolymer (styrene, styrene substitution) (Including homopolymers and copolymers), methyl methacrylate resin, butyl methacrylate resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (silicone modified acrylic resin, vinyl chloride resin modified acrylic resin and acrylic resin) Urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, rosin-modified maleic acid resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene,
Bending fatigue test from polyvinylidene chloride, ionomer resin, polyurethane resin, silicone resin, fluororesin, ketone resin, ethylene-ethyl acrylate copolymer, xylene resin, polyvinyl butyral resin, polyimide resin, polyamide resin and modified polyphenylene oxide resin. One or two of which the number of flexures before breakage is 6000 or more, preferably 25,000 or more, and particularly preferably 45,000 or more.
Can be used more than one kind. Among these materials, fluororesin is particularly suitable. The blending amount of these thermoplastic resins is preferably 55 to 99.8% by mass, and particularly preferably 65 to 98% by mass. If the blending amount of the thermoplastic resin is less than 55% by mass, the mechanical strength of the endless belt becomes brittle, and cracks, tears, fractures, etc. may occur during rotation.

Next, as the conductivity-imparting material, a hydrophilic resin which is incompatible with the thermoplastic resin is preferable. The term "incompatible" as used herein means a state other than a completely compatible system in which, when resins are melt-kneaded, water and ethyl alcohol are dissolved in a molecular state at an arbitrary ratio. Further, the hydrophilic resin is a generic term for resins having a high water absorption rate, and is used for the purpose of imparting conductivity required for an endless belt member for electrophotographic devices. The water absorption of the hydrophilic resin is 10 to
It is preferably 300%, and more preferably 20 to 200%. Water absorption here means JIS
According to K 7209, it is a measured value after immersion in water at a temperature of 23 ° C. for 24 hours. Water absorption of the hydrophilic resin 10%
If it is less than the range, the conductivity imparted to the endless belt is likely to be insufficient. When the hydrophilic resin is blended in an amount of more than 45% by mass in order to enhance the conductivity, it adversely affects the mechanical strength of the endless belt and tends to cause problems such as tearing, delamination and elongation. If the water absorption of the hydrophilic resin exceeds 300%, the environmental resistance of the endless belt will fluctuate greatly, and depending on the environment in which the resin is used, the image quality will be degraded and paper conveyance will be defective. The hydrophilic resin used in the endless belt in the present invention is preferably a polyether ester amide which is a block copolymer having a polyether segment and a polyamide segment in the molecule as a hydrophilic resin containing a polyether component in the molecule, and Examples include polyether amide, block copolymer of polyethylene oxide and epichlorohydrin, block copolymer of polyethylene oxide and polypropylene oxide, and graft copolymer in which polyethylene oxide is introduced into the side chain, and a copolymer containing a quaternary ammonium salt group. Examples of the polymer include a quaternary ammonium salt group-containing methacrylate copolymer, a quaternary ammonium salt group-containing maleimide copolymer, and a quaternary ammonium salt group-containing methacrylimide copolymer. Sodium polystyrene sulfonate as copolymers containing phosphate base.

Further, as a conductivity-imparting material other than these hydrophilic resins, alkali metal sulfonate having a fluorine atom in the molecule is preferable. Specific examples include lithium trifluoromethanesulfonate, potassium perfluorooctanesulfonate, lithium perfluorooctanesulfonate, and cesium perfluorooctanesulfonate.

Further, various materials other than those listed above can be used as the conductivity-imparting material. Regarding the influence of the conductivity-imparting material on the dispersion state and the mechanical properties of the endless belt, It requires more attention. Specifically, for example, as an electron conductive material, carbon black, graphite, aluminum-doped zinc oxide, tin oxide-coated titanium oxide, tin oxide, tin oxide-coated barium sulfate, potassium titanate, antimony oxide, indium oxide, zirconium oxide. , Zinc oxide, aluminum metal powder, nickel metal powder, and the like, and examples of the ion conductive resistance control material include tetraalkylammonium salt, trialkylbenzylammonium salt, alkyl sulfate, sorbitan fatty acid ester, and polyoxyethylene alkyl. Examples thereof include amines, polyoxyethylene fatty acid alcohol esters, alkyl betaines and lithium perchlorate. The content of these conductivity imparting agents is preferably 0.2 to 45% by mass, more preferably 2 to 35% by mass.

A compatibilizer or dispersant may be added for the purpose of appropriately controlling the dispersion state of the conductivity-imparting material in the thermoplastic resin. Examples of the compatibilizer / dispersant include, for example, ethylene-glycidyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, a substance selected from polypropylene and low-density polyethylene, styrene, and methacrylate. ,
Examples thereof include a graft copolymer with a substance selected from an acrylonitrile-styrene copolymer and the like, a block copolymer, a random copolymer and the like.

Next, a method of forming a belt shape using these materials will be described.

FIG. 3 shows a molding apparatus according to the present invention. The device basically consists of an extruder, an annular die and an air blowing device.

FIG. 3 shows an extruder 10 for forming a two-layer belt.
It has two groups of 0 and 110, but in the present invention, it may have at least one group. Next, a method for manufacturing the endless belt of the present invention will be described. First, a molding resin, a conductive agent, an additive, and the like are premixed in advance based on a desired composition, and the kneading-dispersed molding raw material is put into a hopper 120 arranged in the extruder 100. In the extruder 100, the set temperature and the screw configuration of the extruder are selected so that the raw material for molding has a melt viscosity capable of forming a belt in a later step and the raw materials are uniformly dispersed. The forming raw material is melted and kneaded in the extruder 100 to be a molten body, and flows into the annular die 140. Extrusion die 1
An air introduction path 150 is provided in the blower 40, and air is blown into the annular die 140 from the air introduction path 150, so that the melt passing through the die 140 expands and expands in the radial direction.

As the gas blown at this time, nitrogen, carbon dioxide, argon or the like can be selected in addition to air. The tubular film obtained by expansion is pulled upward while being cooled by the cooling ring 160. At this time, the final shape dimension 180 is determined by passing between the dimension stability guides 170. Further, the belt 190 of the present invention can be obtained by cutting this with a desired width in a direction perpendicular to the longitudinal direction.

According to this method, the endless belt can be molded in a single step in a short time with high dimensional accuracy.
Since molding is possible in a short time, mass production and low cost production are possible.

In the extrusion method of the present invention, it is preferable that the thickness of the formed tube film is smaller than the die gap of the annular die. If a molded product of 150 μm is to be produced with a die gap of 150 μm, it is difficult to obtain a molded product with high thickness accuracy because the fluctuation of the die gap in 1 μm units appears almost as it is in the fluctuation of the thickness of the molded product. When a molded product of 150 μm is molded with the die gap of 1, the influence of the die gap in units of 1 μm on the thickness of the molded product is small, so a molded product with high thickness accuracy can be obtained.

Further, it is preferable to set the take-up speed of the cold-formed tubular film higher than the discharge speed of the tubular melt discharged from the tip of the annular die. As a result, a stretching effect is added, and it becomes easy to mold a molded product thinner than the die gap as described above.

The diameter of the tube film to be molded is preferably in the range of 50 to 300% with respect to the die diameter of the annular die. This makes it easier to obtain a molded product thinner than the die gap, as described above. Especially when a resin having a low melt tension and not expanding is used, it is preferable to set the diameter of the tube film in the range of 50 to 100%.

In the present invention, the extruder for extruding the tubular melt is preferably a twin-screw extruder. Due to the compounding effect in the twin-screw extruder, the kneading / dispersing step of the conductive material into the thermoplastic resin and the extruding step can be realized in one step, and the cost can be reduced by reducing the number of steps.

In the present invention, the first layer is obtained by extrusion molding as described above, and the second layer and / or other layers are formed into the first layer.
A multi-layer belt may be formed by coating on a layer belt. Examples of the coating method include spraying, dipping, and flow coating. In particular, when forming a thin film of the third layer for the purpose of imparting releasability on the second layer, layer formation by coating is suitable.

[0043]

The present invention will be described in detail with reference to the following examples.

Example 1 The following raw material ingredients were kneaded and dispersed by a twin-screw extrusion kneader to obtain a kneaded material having a particle size of 1 to 2 mm.

Thermoplastic polyimide: 72% by mass Polyether ester amide (water absorption 54%): 27% by mass Ethylene-glycidyl methacrylate copolymer: 1% by mass

When a bending fatigue test was conducted on a 100 μm-thick sheet made of the thermoplastic polyimide T-die, the number of times until breakage was 61,000. Next, the kneaded product is mixed with the uniaxial extruder 10 shown in FIG.
It was put into a hopper 120 of 0 and extruded to obtain a melt. The melt was subsequently introduced into a cylindrical extrusion die 140. Therefore, air is blown from the air introduction path 150 to expand and expand, and the final shape and dimension is 220 m inside diameter.
m, thickness 100 μm, and further cut with a belt width of 250 mm to obtain an endless belt. In addition, the runout of the inner peripheral length and the outer peripheral length of the endless belt in the longitudinal direction was ± 1.3 mm. The thickness fluctuation in each part of the endless belt was ± 3.4%. 500 V is applied by the above-mentioned electric resistance measuring machine, and 6 points in the circumferential direction of the endless belt, and 3 in the axial direction at each position.
The surface resistance was measured at 18 places, and the variation in the resistance inside the belt was measured. The surface resistance value at 18 places was 6.8 × 10 ^{11 to} 8.1 × 10 ¹² Ω. The maximum / minimum surface resistance values were within 100 times. When a bending fatigue test was conducted on the endless belt, the endless belt broke at 52,000 times.

The endless belt is mounted on a full-color electrophotographic apparatus as a transfer / transport belt for transporting a transfer material,
When a full-color image was printed on 80 g / m ² paper, there were no defects such as poor conveyance and misalignment in the image. Further, when 40,000 full-color images were continuously printed, the belt rotation was stable and no meandering was observed. Further, the belt was maintained in the same state as the initial state without cracking, tearing or breaking.

<Example 2> The following raw materials were used in the same manner as in Example 1 to obtain an inner diameter of 220 mm and a thickness of 120 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

Polyvinylidene fluoride: 86% by mass Carbon black: 12% by mass Potassium perfluorooctane sulfonate: 2% by mass

Here, when the bending fatigue test was carried out on a sheet of polyvinylidene fluoride having a T-die of a thickness of 120 μm, the number of times until breakage was 45300 times. The fluctuations of the inner peripheral length and the outer peripheral length in the longitudinal direction of the obtained endless belt were both ± 1.4 mm, and the thickness fluctuation of each portion was ± 1.7%. Further, the surface resistance value at 18 places was 8.2 × 10 ^{10 to} 5.3 × 10 ¹¹ Ω, and the maximum value / minimum value was within 100 times. When a bending fatigue test was conducted on the endless belt, it was found to be 42
It broke 100 times. Example 1 of the endless belt
When a full-color image was printed by mounting it as a transfer / conveyor belt in the same manner as above, no defects such as conveyance defects or misalignment in the image were observed, and when continuous printing of 40,000 full-color images was performed, the rotation of the belt was stable. No meandering was seen. Further, the belt was maintained in the same state as the initial state without cracking, tearing or breaking.

<Embodiment 3> Using the following ingredients, in the same manner as in Embodiment 1, the inner diameter was 220 mm and the thickness was 120 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

ETFE: 83% by mass Propylene oxide / ethylene oxide copolymer (water absorption 145%): 15% by mass Lithium perfluorooctanesulfonate: 2%

Here, 120 by the T-die of the ETFE
When the bending fatigue test was carried out on a sheet having a thickness of μm, the number of times until breakage was 29,800. The fluctuation of the inner peripheral length and the outer peripheral length in the longitudinal direction of the obtained endless belt is ± 0.8 mm, the thickness fluctuation in each portion is ± 4.0%, and the surface resistance value at 18 places is 7.1.
Maximum value / minimum value is 100 at × 10 ^{10 to} 5.2 × 10 ¹¹ Ω.
It was within double. When a bending fatigue test was performed on the endless belt, the endless belt was broken at 27200 times.

When the endless belt was mounted on a full-color electrophotographic apparatus as an intermediate transfer belt and a full-color image was printed on 80 g / m ² paper, a uniform image without unevenness was obtained. When 40,000 full-color images were continuously printed, rotation was stable and no meandering was observed. Further, the belt was maintained in the same condition as the initial stage without cracking, tearing or breaking.

<Embodiment 4> Using the following ingredients, in the same manner as in Embodiment 1, the inner diameter was 150 mm and the thickness was 120 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

Polyvinylidene fluoride: 78% by mass Polyether ester amide (water absorption 54%): 17% by mass Lithium trifluoromethanesulfonate: 4% by mass Ethylene-vinyl acetate copolymer: 1% by mass

Here, the PVDF T-die 120 is used.
When the bending fatigue test was carried out on a sheet having a thickness of μm, the number of times until breaking was 45300 times. The fluctuations of the inner peripheral length and the outer peripheral length of the obtained endless belt in the longitudinal direction are both ± 1.2 mm, the thickness fluctuation in each part is ± 3.4%, and the surface resistance value at 18 places is 4.7.
The maximum value / minimum value was within 100 times at × 10 ^{5 to} 8.7 × 10 ⁶ Ω. When a bending fatigue test was conducted on the endless belt, it broke at 4,1800 times.

When the endless belt was mounted on a full-color electrophotographic apparatus as a photoreceptor belt and a full-color image was printed on 80 g / m ² paper, a uniform image without unevenness was obtained. When 40,000 full-color images were continuously printed, rotation was stable and no meandering was observed. Further, the belt was maintained in the same condition as the initial stage without cracking, tearing or breaking.

<Comparative Example 1> The following raw materials were used in the same manner as in Example 1 to obtain an inner diameter of 220 mm and a thickness of 120 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

Polycarbonate: 85% by mass Carbon black: 15 mass%

Here, when the bending fatigue test was performed on a 120 μm-thick sheet made of the polycarbonate T-die, the number of times until breakage was 2,200.
The fluctuations of the inner peripheral length and the outer peripheral length of the obtained endless belt in the longitudinal direction were both ± 1.4 mm, and the thickness fluctuation of each portion was ± 4%. Further, the surface resistance value at 18 places was 2.2 × 10 ^{10 to} 3.5 × 10 ¹² Ω, and the maximum value / minimum value exceeded 100 times. When a bending fatigue test was performed on the endless belt, the endless belt broke at 1800 times. When the full-color image was printed by mounting the endless belt as a transfer / conveying belt in the same manner as in Example 1, misalignment was observed in the image. When 40,000 full-color images were continuously printed, the belt broke in the middle.

<Comparative Example 2> The following raw materials were used in the same manner as in Example 1 to obtain an inner diameter of 220 mm and a thickness of 120 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

ETFE: 88% by mass Carbon black: 12 mass%

Here, the T-die of the ETFE 120
When the bending fatigue test was carried out on a sheet having a thickness of μm, the number of times until breakage was 29,800. The fluctuations of the inner peripheral length and the outer peripheral length of the obtained endless belt in the longitudinal direction were both ± 1.0 mm, and the thickness fluctuation of each portion was ± 2.8%. Further, the surface resistance value at 18 places was 5.2 × 10 ^{9 to} 8.2 × 10 ¹¹ Ω, and the maximum value / minimum value exceeded 100 times. When a bending fatigue test was performed on the endless belt, it broke at 24500 times. When the full-color image was printed by mounting the endless belt as a transfer / conveying belt in the same manner as in Example 1, misalignment was observed in the image due to defective adsorption of the transfer material. When 40,000 full-color images were continuously printed, the rotation was stable and no meandering was observed. Also, without cracking, tearing or breaking of the belt,
It kept the same condition as the initial one.

<Comparative Example 3> Using the following ingredients, in the same manner as in Example 1, the inner diameter was 220 mm and the thickness was 120 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

Polycarbonate: 95% by mass Polyether ester amide (water absorption 54%): 5% by mass

Here, when the bending fatigue test was conducted on a sheet having a thickness of 120 μm using the T-die of the polycarbonate, the number of breaks was 2,200.
The fluctuations of the inner circumference and the outer circumference in the longitudinal direction of the obtained endless belt are both ± 1.4 mm, the thickness fluctuation in each part is ± 4.5%, and the surface resistance value at 18 places is 7.1 × 10. ^The maximum value / minimum value was within 100 times at ^{13 to} 2.3 × 10 ¹⁴ Ω. When a bending fatigue test was performed on the endless belt, it broke at 2,300 times.

When the endless belt was mounted on a full-color electrophotographic apparatus as an intermediate transfer belt and a full-color image was printed on 80 g / m ² paper, a uniform image was obtained. When 40,000 full-color images were continuously printed, the edge of the belt was torn.

<Comparative Example 4> The following raw material formulations were used and the same method as in Example 1 was used to prepare an inner diameter of 150 mm and a thickness of 100 μm.
An endless belt having a width of m and a width of 250 mm was obtained.

Polycarbonate: 67% by mass Polybutylene terephthalate: 15 mass% Carbon black: 18% by mass

Here, T of a kneaded material of 67 parts by mass of the polycarbonate and 15 parts by mass of the polybutylene terephthalate.
When the bending fatigue test was performed on a 100 μm thick sheet by a die, the number of times until breakage was 2,700. The fluctuations of the inner peripheral length and the outer peripheral length in the longitudinal direction of the obtained endless belt are both ± 2.3 mm, the thickness fluctuation in each part is ± 6.2%, and the surface resistance value at 18 places is 2.5 × 10 5. ^The maximum value / minimum value exceeded 100 times at ^{6 to} 2.1 × 10 ⁹ Ω. When a bending fatigue test was performed on the endless belt, the endless belt broke at 2500 times.

The endless belt was mounted on a full-color electrophotographic apparatus as a photoconductor belt and a full-color image was printed on 80 g / m ² paper, and a nonuniform image with unevenness was obtained. When 40,000 full-color images were continuously printed, the rotation was unstable and meandering was observed. Further, the belt was torn and broken from the end portion during the durability test.

[0073]

According to the present invention, in particular, a transfer / conveying belt,
When used as an intermediate transfer belt or a photoconductor belt, uniform and uniform image quality without white spots and hollow spots is achieved, and belt cracking during belt running
(EN) An endless belt member which does not cause breakage, can realize stable rotation, has a small number of steps, is low in cost, and has high dimensional accuracy, and an electrophotographic apparatus including the member.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing an example of an electrophotographic apparatus to which an intermediate transfer belt manufactured by a manufacturing method of the present invention is applied.

FIG. 2 is a longitudinal sectional view schematically showing an example of an electrophotographic apparatus to which a transfer / conveyor belt manufactured by the manufacturing method of the present invention is applied.

FIG. 3 is a vertical sectional view schematically showing an example of a forming apparatus used in the manufacturing method of the present invention.

[Explanation of symbols]

1 photosensitive drum 2 Primary charger 3 image exposure 7 Charging member for cleaning 10 guides 11 Paper feed roller 12 Transfer conveyor belt 13 Cleaning device 15 Fixer 20 Intermediate transfer belt 28,29 Bias power supply 33-36 Bias power supply 41-44 developing device 62 Primary transfer roller 63 Secondary transfer roller 100,110 extruder 120,130 hopper 140 ring die 150 air introduction path 160 cooling ring 170 Dimensional stability guide 190 endless belt P transfer material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Akihiko Nakazawa             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Atsushi Tanaka             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tsunetoku Ashibe             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Takashi Kusaba             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 2H035 CA05 CB06                 2H171 FA07 FA09 FA10 FA20 FA24                       FA26 PA03 PA05 QA03 QA08                       QA09 QA18 QA24 QB03 QB15                       QB34 QC03 QC36 SA32 TA01                       TA16 TB02 TB13 TB14 UA03                       UA07 UA22 XA03                 2H200 FA13 GA23 GA47 GB12 GB25                       HA03 HB12 HB22 JA02 JB07                       JB45 JB46 JB47 JB48 JC04                       JC15 JC16 JC17 JC18 LC03                       LC04 MA04 MA11 MA13 MA14                       MA17 MA20 MB04 MB05 MC03                       MC20 NA02

Claims (9)

[Claims] 1. A charging means for applying an electric charge to an electrophotographic photosensitive member, an image exposing means for forming an electrostatic latent image on the electrophotographic photosensitive member, and a visible image is formed by developing the electrostatic latent image with toner. In an endless belt member used in an electrophotographic apparatus having a developing means for transferring and a transfer means for transferring a toner image to a transfer material, the endless belt member is made of a resin composition containing at least a thermoplastic resin and a conductivity-imparting material. And the maximum / minimum value of the surface resistance of each part of the endless belt member is 100 times or less, and the deflection of the inner peripheral length in the longitudinal direction is within ± 1.5 mm, and until the fracture in the bending fatigue test. An endless belt member characterized by being bent 5000 times or more. 2. The endless belt member comprises 55 to 99.8% by mass of the thermoplastic resin and 0.2 to 4 of the conductivity imparting material.
A resin composition containing 5% by mass of the resin composition, wherein the thermoplastic resin has a bending frequency of 6000 times or more before breaking in the bending fatigue test, and the resin composition is extruded by an annular die of an extruder. The endless belt member according to claim 1, which is obtained by cutting the formed tubular film in a direction perpendicular to the longitudinal direction. 3. The endless belt member according to claim 1, wherein the fluctuation of the thickness of each part of the endless belt member is within ± 5.0%. 4. The conductivity-imparting material is a hydrophilic resin that is incompatible with the thermoplastic resin, the hydrophilic resin has a water absorption of 10 to 300%, and the hydrophilic resin is The endless belt member according to any one of claims 1 to 3, which contains a polyether component in the molecule. 5. The endless belt member according to claim 1, wherein the conductivity-imparting material is an alkali metal sulfonate having a fluorine atom in the molecule. 6. The endless belt member according to claim 4, wherein the resin composition contains a compatibilizing agent that promotes compatibilization between the thermoplastic resin and the hydrophilic resin. 7. The endless belt member according to claim 1, wherein the thermoplastic resin is a fluororesin. 8. The endless belt member according to claim 1, wherein the endless belt member is an intermediate transfer belt, a transfer / conveyance belt or a photoconductor belt. 9. A charging means for applying an electric charge to an electrophotographic photosensitive member, an image exposing means for forming an electrostatic latent image on the electrophotographic photosensitive member, and a visible image is formed by developing the electrostatic latent image with toner. An electrophotographic apparatus having a developing means for performing the transfer and a transfer means for transferring a toner image onto a transfer material, comprising the endless belt member according to any one of claims 1 to 8.