JP2007171819A - Seamless belt and image forming apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt which neither meanders nor causes a problem resulting from anisotropy of its strength when it is used as a transfer belt etc. <P>SOLUTION: Provided is the laminated semiconductor seamless belt characterized in that in the resin belt obtained by laminating an oriented thermoplastic resin film, resin directions at least at its end part of the resin belt are made orthogonal and laminated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention employs a transport belt used for transporting precision parts to a predetermined position while ensuring high precision, and more specifically, an image forming process such as an electrophotographic method or an electrostatic recording method is employed. In image forming apparatuses, various types of belts for image forming apparatuses that are required to convey the toner carrier formed at the time of driving various rollers and belts to high-precision positions, particularly transfer belts, intermediate transfer belts, fixing belts, etc. It can be used effectively as a functional component.

  Conventionally, a seamless belt used in an electrophotographic copying machine or the like is formed seamlessly with flexibility, and is wound around a plurality of rollers and used as an intermediate transfer belt or the like.

  As a method for producing a thin seamless belt, tube, or tubular film using such a resin, (1) an extrusion hot melt molding method represented by an inflation method, (2) a resin or a precursor thereof is in a solution state, A casting method or the like is already known in which a predetermined amount is applied on the inner or outer surface of a tubular mold and stripped after a solvent removal treatment (heat treatment as necessary). In addition, when using seamless belts as functional parts such as various belts for image forming apparatuses, particularly transfer belts, intermediate transfer belts, and fixing films, strict film thickness accuracy is required. Has been proposed.

  That is, Patent Document 1, Patent Document 2 and the like have been proposed as a method of (3) winding a sheet-like film around a core body, welding both ends of the sheet, and lining the inner surface of the hollow tubular body. Further, (4) as shown in Patent Document 3, first, a sheet-like film is wound around a columnar member so that the winding start and end are overlapped. Then, a tubular mold member is fitted to the outside of the wound film, and then the whole is heated, and the overlapped portion of the film is joined to make the sheet-like film a resin belt. At that time, it has already been proposed to control the completed belt shape with high accuracy by setting the relationship between the thermal expansion coefficients of the cylindrical member to be used and the tubular mold member to be cylindrical member> tubular mold member.

In particular, in the method of forming a sheet-like film into a tubular belt by joining the overlapping portions of the film of (4) above, since the raw sheet-like film is produced by an extrusion molding method, crystal orientation occurs in the raw film. Even after it is formed into a tubular belt, the orientation remains. Therefore, by matching the crystal orientation of the raw material sheet with the direction of rotation when the formed tubular belt is used as a transfer belt, the strength is increased with respect to the tension tension direction and the belt rotation direction. It has been proposed to produce a highly resistance-controlling seamless resin belt (Patent Document 4).
JP 63-34120 A JP-A-63-34121 JP-A-8-187773 Japanese Patent Application Laid-Open No. 2004-167943

  When a seamless belt manufactured by the method described above is used as a transfer belt, etc., the influence of the circumferential variation in the longitudinal direction of the rotating belt, the applied tension bias, the inclination of the winding roller, etc. The belt may meander due to influences.

  When trying to correct this meander, stress acts between the inner wall of the rib that is provided on the inner peripheral surface of the end of the seamless belt and the end of the roller, causing the rib to deform and get over the end of the roller. The auctioning phenomenon that tries to occur occurs. Further, since the rib provided in the seamless belt bends to the roller with a smaller curvature, a stress is generated to swell outward from the bend.

  Further, in a transfer belt having a mechanism in which meandering is controlled by being abutted against a wall with a belt having no ribs, extreme stress is generated at the abutted portion due to end deformation and rebound stress. As described above, since a large stress acts on the end portion of the seamless belt, there is a problem that a crack occurs in the vicinity of the end portion or the rib and breaks. On the other hand, in order to prevent cracks and breaks, the end of the seamless belt is reinforced with an adhesive tape or the like. However, if it is simply reinforced with an adhesive tape or the like, new disadvantages and inconveniences such as expansion of the ineffective area, peeling of the tape with a cleaning blade, and an increase in the number of steps for manufacturing will newly occur. Furthermore, stress concentration due to shape factors occurs at the ends of the reinforcing tape and the belt, which may cause breakage.

  In particular, as described in Japanese Patent Application Laid-Open No. 2004-167943, by aligning the crystal orientation of the raw material sheet and the rotation direction when the molded seamless belt is used as a transfer belt, the tension stretching direction and the belt When a resistance-controlled seamless resin belt was produced by increasing the strength in the rotational direction, the strength in one direction (circumferential direction) was increased because the strength in one direction was increased when a crack occurred from the end. However, there is a problem that the seamless belt is cut in the circumferential direction.

  The present invention has been made in view of the above, and suppresses the occurrence of cracks at the ends and the like, and prevents the breakage.In addition, the problem of expansion of the ineffective area, peeling of the tape by the cleaning blade, and an increase in the number of processes is provided. An object of the present invention is to provide a seamless belt which is eliminated and does not expand in one direction even if a crack occurs.

  In order to achieve the above-mentioned problems, in the seamless belt formed by seamlessly laminating the semiconductive resins of the sheet-like film, the orientation direction of the resin of the sheet-like film as a raw material is orthogonal to at least the end portion of the seamless belt. It is characterized by being laminated. In addition, the tear strength in the width direction of the end portion is improved, and at the same time, as described above, the center portion matches the orientation of the raw material sheet with the rotation direction when the formed seamless belt is used as a transfer belt, thereby increasing the tension. Thus, a more durable seamless belt can be obtained by maintaining the strength increased with respect to the stretching direction of the belt and the rotation direction of the belt. Furthermore, by laminating by heat fusion, peeling from the end portion does not occur, and stress concentration due to shape factor does not occur.

Of course, when the rib is provided only on the inner peripheral surface of one end, only the end provided with the rib may be laminated with the resin direction of the raw sheet-like film orthogonal to each other. .
When ribs are provided on the inner peripheral surfaces of the end portions on both sides, it is preferable that the resin directions of the sheet-like film as a raw material are laminated so as to be orthogonal to the end portions of both ribs.

  As described above, according to the present invention, in a manufacturing method for producing a seamless belt used for an electrophotographic copying machine or the like from a sheet-like film, the end of the seamless belt is laminated with the resin direction of the sheet-like film orthogonal to each other. By doing so, it is possible to effectively suppress or prevent the end of the seamless belt from cracking and breaking, and to prevent the breakage from expanding in one direction even if a crack occurs. In addition, there are effects that the problems of expansion of the ineffective area, peeling of the tape by the cleaning blade, and increase in the number of processes can be solved. As a result, a highly durable seamless belt can be produced with high productivity and at low cost.

  In the method of producing a seamless belt formed by laminating and heat-sealing semiconductive resins of a sheet-like film, the orientation direction of the resin of the sheet-like film as a raw material at least at the end of the seamless belt It was aimed to obtain a highly durable seamless belt with improved tear strength in the width direction at the end by laminating them at right angles.

  In this example, a seamless belt was produced from a sheet-like film using the method disclosed in JP-A-8-187773.

Next, the sheet-like film material applicable to this example is shown.
The film material that can be used in the present invention is suitable for use as long as it is a thermoplastic resin material, and in particular, polyethylene, polypropylene, polymethylpentene-1, polystyrene, polyamide, polycarbonate, polysulfone, polyarylate, Polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyether sulfone, polyether nitrile, thermoplastic polyimide materials, polyether ether ketone, thermotropic liquid crystal polymer, ABS, polyether imide, ethylene vinyl alcohol, acrylonitrile lolitadiene -All thermoplastic resin materials such as styrene resin and polyamic acid and blended resins thereof, and thermoplastic elastomers formed from the above blends are more suitable for use. That. Among these, a preferable resin includes polyether ether ketone which is a crystalline polymer. However, even an amorphous polymer is sufficiently effective as long as it is stretched in the extrusion direction during sheet molding. However, even amorphous polymers that are oriented in the extrusion direction during processing, for example, those that are stretched in the extrusion direction during processing are sufficiently effective.

  In addition, a film in which at least one of organic and inorganic fine powders is blended with the above resin material for the purpose of heat resistance reinforcement, conductivity, and thermal conductivity, or a film that is stretch-strengthened at any magnification can be used.

  Here, as organic fine powder, for example, condensation type polyimide powder, ion conductive material, etc., and as inorganic fine powder, carbon black powder, carbon fiber or carbon tube, magnesium oxide powder, magnesium fluoride powder, silicon oxide Powder, aluminum oxide powder, boron nitride powder, aluminum nitride powder, inorganic spherical fine particles such as titanium oxide powder, fibrous particles such as carbon fiber and glass fiber, whisker-like powder such as potassium titanate, silicon carbide, silicon nitride, etc. Fine powders of any shape and size can be used. A particularly preferable fine powder is carbon black powder. It is preferable because it is easy to control to the target resistance value and is less dependent on the environment.

    Furthermore, an elastomer component can be included as an optional component for improving toughness in an amount of, for example, 50 parts by mass or less with respect to 100 parts by mass in total of the resin component and the conductive substance. Elastomer components include natural rubber, butadiene polymer, styrene-isoprene polymer, butadiene-styrene copolymer, and hydrogenated products thereof (including random copolymers, block copolymers, graft copolymers, etc.) , Isoprene polymer, chlorobutadiene polymer, butadiene-acrylonitrile copolymer, isobutylene polymer, isobutylene-butadiene copolymer, isobutylene-isoprene copolymer, acrylate polymer, ethylene-propylene copolymer, ethylene- Examples include propylene-diene copolymer, thiocol rubber, polysulfide rubber, polyurethane rubber, polyether rubber (eg, polypropylene oxide), epichlorohydrin rubber, and the like. Particularly preferred is a polyolefin-based elastomer because of the ease of sheet extrusion.

  In addition, an antioxidant, a heat stabilizer, a heat aging inhibitor, an antifungal agent, a plasticizer, a crystal nucleating agent, a fluidity improver, an ultraviolet absorber, a lubricant, a mold release agent, and a dye within a range not impairing the object of the present invention. A film to which one or more usual additives such as a colorant such as a pigment, a flame retardant, and a flame retardant aid are added can be used.

  Further, different types of resins may be used for the sheet-like film 1 as long as the object of the present invention is not impaired. However, since the sheet-like film is bonded by heat fusion, it is preferable to use a resin having a glass transition point (Tg) and a melting point (Tm) close to each other. Of course, it is possible to make adjustments such as changing the material physical properties in an inclined manner or increasing the thickness of the end portion.

  The width of the end portion laminated with the resin directions orthogonal to each other is not particularly limited, but is preferably about 5 to 20 mm wider than the width of the rib 19 as shown in FIG. 5 and about 8 to 30 mm.

  The rib 19 is selected from urethane resin, NBR, thermoplastic elastomer, etc., which are elastic bodies having high mechanical strength and wear resistance. However, in general, a urethane resin having a hardness of 50 to 80 ° (JIS-A), a width of 3 to 6 mm, and a thickness of about 1 mm is used. The rib 19 may be attached via a double-sided adhesive tape. Further, the end portions of the ribs 19 can be butted and joined together by a method such as stepped overlapping, overlapping, or seam joining, or the ribs 19 can be omitted if it is not necessary. Is possible.

  Embodiments of the seamless belt of the present invention will be described below based on examples.

  In this example, a seamless belt was produced from a sheet-like film by using the method shown in the claims and examples of Japanese Patent Laid-Open No. 8-187773 for winding and fixing the first sheet.

Example 1
In Example 1, polyether ether ketone (hereinafter referred to as PEEK) resin is kneaded and molded as a sheet-like film having a thickness of 50 μm by a hot melt extruder (not shown) as a sheet-like film 1 and ketjen black is used as an internal additive. Particles were mixed and a volume resistance value controlled to 1.0E + 10 Ω · cm was used.

A hollow cylindrical member 2 was used as a core rod around which the thermoplastic sheet film 1 was wound, and a hollow tubular member 3 covering the sheet film 1 and the cylindrical member 2 was used. The tubular mold member 3 has an inner diameter through which the cylindrical member 2 is inserted.
The material of the tubular mold member 3 is a cast iron material, and its inner surface is subjected to nickel plating coating in consideration of releasability from the sheet-like film 1.

As the tubular member 3, Novinite CN-5 (manufactured by Enomoto Foundry) was used. The thermal expansion coefficient of the cylindrical member 2 of the used aluminum material is 2.40 × 10 ⁻⁵ / ° C., and the thermal expansion coefficient of the tubular mold member 3 is 4.0 × 10 ⁻⁶ / ° C.
The cylindrical member 2 had an outer diameter of 300.00 mm, an inner diameter of 270.00 mm, and a length of 350 mm. Further, the tubular member 3 has an outer diameter of 320.0 mm, an inner diameter of 300.45 mm, and a length of 350 mm.

  Moreover, in the present Example 1, the dimension of the said cylindrical member 2 and the tubular type | mold member 3 is the outer diameter of the cylindrical member 2, and the tubular type | mold member 3 at the time of the heating in the heating process mentioned later, ie, the heating temperature of 360 degreeC. Is designed in advance so that the difference in the inner diameter dimension of each becomes 100 μm.

  First, a sheet-like film 1a was prepared by cutting PEEK resin into a sheet having a length and width of 944.0 mm × 330 mm.

  As shown in FIG. 1, the prepared sheet-like film 1 a was wound around the outer peripheral surface 2 a of the cylindrical member 2 once. At this time, the sheet-like film 1a was wound so that the direction (MD direction) in which the crystals were oriented at the time of extrusion molding was the circumferential direction of the columnar member. In addition, the difference in the position of the winding start part and the winding end part of the sheet was 2 mm.

  Next, a sheet-like film 1b was prepared which was made of the same PEEK resin as that of the sheet-like film 1a and was cut into 944.0 mm × 295.0 mm. The sheet-like film 1b was wound around the center of the sheet-like film 1a obtained by winding the sheet-like film 1b around the cylindrical member 2 as shown in FIG. At this time, the sheet-like film 1b was wound so that the direction (MD direction) in which the crystals were oriented at the time of extrusion molding was the circumferential direction of the columnar member.

  Next, sheet-like films 1c and 1d made of the same PEEK resin as the sheet-like films 1a and 1b were cut into 944.0 mm × 18 mm. The sheet-like films 1c and 1d were cut so that the direction (MD direction) in which the crystals were oriented during extrusion molding was the transverse direction. As shown in FIG. 3, the sheet-like films 1a, 1c, and 1d are laminated so that the MD directions of the sheet-like films 1a, 1c, and 1d are orthogonal to each other at both ends of the sheet-like film 1b. Wound around in the circumferential direction. Note that the overlapping positions of the sheet-like films 1b, 1c, and 1d were respectively shifted from the overlapping position of the sheet-like film 1 by 180 ° in the circumferential direction. Further, the difference in position between the winding start portion and the winding end portion of the sheet was 2 mm. In addition, the overlapping amount in the circumferential direction with the sheet-like films 1b, 1c, and 1d was 0.5 mm.

  Then, it inserted in the hollow part 3a of the tubular type | mold member 3 like FIG. FIG. 4 shows a state in which the cylindrical member 2, the sheet-like film 1, and the tubular mold member 3 are combined.

  Then, the process proceeds to the heating process. The cylindrical member 2, the sheet-like film 1, and the tubular mold member 3 were heated while rotating using a heating molding machine comprising a lamp heater. In this embodiment, the molding temperature is 360 ± 5 ° C., and the heating time is 10 min. It was. 10 min. After the heating step, after taking out the above 1, 2, and 3 from the thermoforming machine, the process proceeds to the cooling step.

Thereafter, the cylindrical member 2 and the film 1 were separated from the tubular mold member 3 when the respective members were near room temperature.
As a result, the obtained tubular film retains the crystal orientation of the raw material sheet, so the tubular film itself has crystal orientation in the circumferential direction, and both ends have different circumferential and width directions. The direction was gone. For this reason, the tear strength in the circumferential direction of the end portion of the formed tubular film is 1.5 times or more compared to the value in the circumferential direction of the center portion, and in particular in terms of tension tension by a roller, etc. It was possible to produce a tubular film having a high mechanical strength in the circumferential direction at the end while maintaining a high tensile strength in the belt circumferential direction where a high mechanical strength is required.

  Further, when ribs are provided on the inner peripheral surfaces of both ends of the annular film and used as the transfer belt 5 in FIG. 6, the anisotropy of the ends is reduced and cracks and the like are spread even if stress is concentrated under the ribs. No breakage or the like was observed even when the durability test was performed up to 1000k sheets.

Example 2
In Example 2, polycarbonate (hereinafter PC) resin is kneaded and molded as a sheet-like film having a thickness of 50 μm by a hot melt extrusion molding machine (not shown), and ketjen black particles are mixed as an internal additive. The volume resistance value was controlled to 1.0E + 10 Ω · cm.
The sheet-like film PC used in Example 2 is stretched in the extrusion direction during sheet extrusion. In the sheet-like PC used in Example 2, the tear strength ratio was TD direction / MD direction = 4.5.

The molding method from the sheet to the seamless belt was the same processing method as in Example 1.
Moreover, in the present Example 2, the dimension of the cylindrical member 2 and the tubular mold member 3 is the same as the outer diameter of the cylindrical member 2 and the tubular mold member 3 at the time of heating in a heating process described later, that is, at a heating temperature of 220 ° C. It is designed in advance so that the difference in inner diameter is 100 μm.

  As a result, the obtained tubular film retains the orientation of the raw material sheet, so that the tubular film itself has an orientation in the circumferential direction, and both ends have anisotropy in the circumferential and width directions. It was gone. For this reason, the tear strength in the circumferential direction of the end portion of the formed tubular film is 1.3 times or more compared to the value in the circumferential direction of the center portion, and in particular in terms of tension tension by a roller, etc. It was possible to produce a tubular film having a high mechanical strength in the circumferential direction at the end while maintaining a high tensile strength in the belt circumferential direction where a high mechanical strength is required.

  Further, when ribs are provided on the inner peripheral surfaces of both ends of the annular film and used as the transfer belt 5 in FIG. 6, the anisotropy of the ends is reduced and cracks and the like are spread even if stress is concentrated under the ribs. No breakage or the like was observed even when the durability test was performed up to 1000k sheets.

Comparative Example A comparative example is shown below. The material and dimensions of the cylindrical member 2 and the tubular member 3 used in this comparative example and the material of the sheet-like film 1 are all the same as in Example 2.

Comparative Example 1
In this comparative example 1, in the step of winding a sheet-like film around a cylindrical member, the film extrusion direction (MD direction) was double-wrapped in the circumferential direction of the cylindrical member to produce an annular film. Both ends of the annular film were reinforced in the circumferential direction with a tape to produce a transfer belt. When used as the transfer belt 5 in FIG. 6, the belt is cracked in the circumferential direction in the vicinity of the inner end of the tape with about 200K sheets, and eventually becomes a ring-cut, making it impossible to use thereafter. .

Comparative Example 2
In this comparative example 2, in the process of winding a sheet-like film around a cylindrical member, the extrusion direction (MD direction) of the film was laminated in the opposite direction to that of each example to produce an annular film. As a result, the crystal orientation of the central portion of the produced tubular film was different from that in the example, and thus the value of the breaking elongation in the width direction was larger than the value in the circumferential direction.
When this is used as the transfer belt 5 in FIG. 6, the strength in the circumferential direction at the center of the belt is weaker than the strength in the belt width direction, so that the tension is applied for a long time while the rotation of the belt is stopped. When it was laid, the belt creep-deformed, and curling habits that were the same as the roller diameter occurred in the belt circumferential direction. Since the belt in which the curl has occurred is deformed in the belt rotation direction, it is difficult to rotate the belt again, which is a problem in using the actual machine.

  Furthermore, when the belt shown in this comparative example was subjected to a 100K endurance test, wrinkles occurred at the center of the belt, and subsequent durability was difficult.

It is the figure which showed an example of the winding method of the film in the Example of this invention. It is the figure which showed an example of the winding method of the film in the Example of this invention. It is the figure which showed an example of the winding method of the film in the Example of this invention. It is the figure which showed an example of the winding method of the film in the Example of this invention. It is the figure which showed an example of the outline of sectional drawing of the edge part of the lamination | stacking semiconductive seamless belt obtained by this invention. It is sectional drawing which shows roughly an example which applied the lamination semiconductive seamless belt obtained by this invention to the image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet-like film 2 Cylindrical member 3 Tubular type | mold member 4 Thin-film-like member 5 Transfer belt 6 Photosensitive drum 7 Charging charger 8 Optical writing device 9 Developer 10 Toner 11 Drive roller
12 Drive roller 13 Followed roller 14 Followed roller 15 Paper (transfer paper)
16 Charger 17 Fixing Device 18 Fixing Film 19 Rib

Claims (4)

  In a resin belt in which a thermoplastic resin film oriented in the direction in which the central portion coincides with the rotation direction of the seamless belt is laminated, the orientation direction of the resin at least at the end of the resin belt is laminated perpendicularly to the central portion. Laminated semi-conductor seamless belt characterized by   2. The laminated semiconductive seamless belt according to claim 1, which is laminated by heat fusion. A conductive film is added to a thermoplastic resin to form a composition film provided with semiconductivity so that the volume resistivity is in the range of 1.0 × 10 ^{6 to} 1.0 × 10 ¹¹ Ω · cm. The laminated semiconductive seamless belt according to 1 or 2.   An image forming apparatus comprising the laminated semiconductive seamless belt according to claim 1.

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