JP2003300242A - Method for producing seamless resin belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a seamless resin belt which is excellent in productivity and low in costs and has a meander preventing guide. <P>SOLUTION: The method has an extrusion process in which a thermoplastic resin is extruded continuously from an extruder 1 into a continuous resin cylinder 7 and a cutting process in which the continuous resin cylinder 7 is cut longitudinally to obtain a belt 10. The extrusion process has a flat belt part 12 forming step in which the molten resin is extruded at a constant discharge speed, and the continuous resin cylinder is received at a constant receiving speed and a thick wall part forming step for forming a thick wall part by increasing the discharge speed and/or decreasing the receiving speed. In the cutting process, the continuous resin cylinder 7 is cut in the thick wall part or its vicinity to obtain the seamless belt having a guide part 14 in at least one end part. <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 a resin seamless belt having a guide portion, and more specifically, to a resin usable as a conveyor belt, a transfer belt, a transfer conveyor belt, etc. in an electrophotographic image forming apparatus. Relates to a method for manufacturing a seamless belt.

[0002]

2. Description of the Related Art In electrophotographic image forming apparatuses, endless belts are often used in photosensitive devices, transfer devices, conveying devices, and the like. FIG. 7 shows an example of an image forming apparatus using an intermediate transfer belt as the transfer device. Photoconductor 3
The surface of No. 1 is uniformly charged by the charging roller 33, and the electrostatic latent image corresponding to the image is formed by the exposure device 32. This electrostatic latent image is developed by the developing device 35 and becomes a toner image. The toner image is transferred to the intermediate transfer belt 36 by the electrostatic transfer member 40. The toner image transferred to the intermediate transfer belt 36 is transferred to the recording paper 41 by the pressing roller 42 and is sent to the fixing roller 46 by the guide 44.
It is fixed. The residual toner on the photoconductor 31 is sufficiently removed by the cleaning blade 34 in preparation for the next image formation. The intermediate transfer belt is supported by a plurality of rollers 37, 38, 39 including drive rollers.

In copiers, printers, facsimiles, etc., it is always required to improve the image accuracy. For such high-precision image formation, it is necessary to drive the belt with high accuracy so as not to cause meandering. Required. In order to drive the belt with high accuracy, it is necessary that the dimensional accuracy of the belt, the parallelism of the axes of the rollers, the roundness of the rollers, and the straightness are all high.
There is a limit to the accuracy improvement of the rollers and the like, and the higher the accuracy, the more expensive it becomes, which violates the demand for the price reduction of the image forming apparatus.

As a technique for improving the endless belt to prevent the meandering, for example, as disclosed in JP-A-59-230950 and JP-A-62-50873, a hot melt adhesive or a room temperature curable silicone is used. Of forming a meandering-preventing guide by using, a technique of adhering a meandering-preventing guide by using a pressure-sensitive adhesive, and JP-A-2000-2898.
As disclosed in Japanese Patent Laid-Open No. 22 and Japanese Patent Laid-Open No. 2000-289823, a technique is known in which a meandering prevention guide using a rubber material is attached to an end portion of a seamless belt made of resin.

[0005]

However, attaching the guide member for preventing the meandering after manufacturing the seamless resin belt requires a separate processing step, resulting in poor productivity,
There is a problem of high cost.

An object of the present invention is to provide a method for producing a seamless resin belt having a guide portion for preventing meandering which is excellent in productivity and low in cost.

[0007]

DISCLOSURE OF THE INVENTION The present invention comprises an extrusion step of continuously extruding a thermoplastic resin from an extruder to form a continuous cylindrical body, and a cutting of the continuous cylindrical body in a longitudinal direction to form a belt. A method for manufacturing a seamless resin belt having a step, wherein the extruding step is a flat belt portion forming step of extruding the molten thermoplastic resin at a constant discharge speed and pulling out the continuous cylindrical body at a constant take-up speed. A thick-walled portion forming step of forming a thick-walled portion by performing at least one of an increase in the discharge speed and a decrease in the take-up speed, and the cutting step includes cutting the continuous cylindrical body at the thick-walled portion or in the vicinity thereof. And a seamless belt having guide portions at both ends.

With the above structure, the guide portion for preventing the meandering is integrally formed with the belt when the belt is manufactured.
A separate step of adhering the meandering prevention guide is unnecessary, and it is possible to manufacture a seamless resin belt having a guide portion with excellent productivity and at low cost.

In the above-mentioned method for producing a seamless resin belt, in the extruding step, a plurality of cylindrical mandrels each having a first fitting portion at one end and a second fitting portion at the other end are provided. By fitting the first fitting part to the second fitting part of another mandrel, the mandrel is continuously provided in a straight line and supplied to the resin extruding part of the extruder, and the continuous cylindrical body is provided on the outer peripheral surface of the mandrel. The mandrel has a recess formed on at least one end of the outer periphery thereof, and when the mandrel is continuously provided, the recess forms the thick portion of the belt on the outer periphery of the joint. It is preferably configured so that possible recesses are formed.

With this structure, the guide portion for preventing the meandering with a high dimensional accuracy of the shape can be formed integrally with the belt in the circumferential direction of the inner surface of the seamless resin belt.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the method for producing a seamless resin belt of the present invention will be described with reference to the drawings. FIG. 1 shows an example of an extruder for molding a belt. The extruder 1 includes a screw unit 3, a drive unit 6 that drives the screw, and a head 5, and a continuous cylindrical body 7 of a thermoplastic resin is continuously extruded from the head 5. A seamless resin belt is formed by cutting the continuous cylindrical body 7 to have a predetermined length, that is, a predetermined belt width. In this figure, the continuous cylinder 7 is
Although it is extruded downward at right angles to the direction of the screw, it may be extruded horizontally or obliquely downward.

Although a take-up device is not shown in FIG. 1, a known take-up device can be used. For example,
When extruding in a horizontal direction which is the same as the direction of the screw, a conveyor device or the like can be used.

In forming the continuous cylindrical body 7, the head 5 is used.
A raw material resin may be extruded into a cylindrical shape by mounting a mandrel in the extrusion direction (D direction) of the continuous cylindrical body 7 from the upper part of the head 5 in FIG. May be formed. In this case, it is preferable that the head 5 is a cross head that pushes out the resin in a direction orthogonal to the screw direction, as shown in FIG.

The continuous cylindrical body 7 is appropriately cut to have a predetermined belt width. Before cutting, the resin belt is cooled by an appropriate means.

FIG. 2 shows an example of a seamless resin belt in which the meandering prevention guide portion of the flat belt portion 12 is integrally formed. Each of these belts 10 includes a flat belt portion 12 and a guide portion 14 formed near both ends of the belt.
Is to have. In the belt of FIG. 2A, the guide portion 14 has a substantially rectangular cross section, and is formed on the edge of the belt. FIG. 2B shows an example in which the guide portion 14 has a substantially semicircular shape and is formed slightly inside the end portion of the belt.

An example of the shape of the thick portion and the shape of the guide portion 14 for forming the guide portion 14 is shown in FIG. Figure 3 (a)
Shows a method of forming a thick portion having a semicircular cross section on the flat belt portion 12 of a continuous tubular body, and cutting the central portion of the thick portion at position C to form the meandering prevention guide 14. It is a thing. In FIG. 3B, a thick portion having a substantially trapezoidal cross section is formed on the flat belt portion 12 of a continuous tubular body, and the central portion of the thick portion having the substantially trapezoidal shape is cut at position C to prevent the meandering. 14 shows a method of forming 14. In the example of FIG. 3 (c), a thick portion having a substantially trapezoidal cross section is formed at two locations on the flat belt portion 12 of the continuous tubular body at a small interval, and a central portion C of the two thick portions is formed. It shows a method of cutting at a position to form the guide portion 14. In the example of FIGS. 3A and 3B, the guide portion 14 is formed at the end portion of the belt, but in the example of FIG. 3C, the guide portion 14 is formed slightly inside the end portion of the belt. .

The number of guide portions 14 formed on one seamless resin belt described above is not particularly limited.
Although it may be one or two or more, one or two is preferable in view of ease of production and stability of the meandering prevention effect. The cross-sectional shape of the guide part is square, rectangular,
A trapezoidal shape, a circumferential shape, a semi-elliptical shape, etc. are exemplified, and are not particularly limited. The guide portion 14 may be formed continuously, but may partially have a discontinuous portion.

An example of manufacturing a seamless resin belt using a mandrel is shown in a sectional view in FIG. The mandrel 18A is cylindrical and has a first fitting portion 23A at one end.
The second fitting portion 23B is provided at the other end, and the mandrel 18
The second fitting portion 23A of A is another mandrel 1 that is continuously provided.
It can be fitted to the first fitting portion 24B of 8B. The plurality of mandrels 18A, 18B, 18C and the like are configured so that they can be arranged linearly by repeating such fitting. The continuously provided mandrels are supplied to the crosshead 5 from, for example, the direction D in FIG. 1, and the continuous tubular body 7 is formed around the crosshead 5.

It is a preferable mode to provide the mandrel 18 (18A, 18B ...) With a hole 19 at the center thereof.
The formation of the holes 19 reduces the weight of the mandrel and facilitates handling.

In the example shown in FIG. 4, concave lines are formed on the outer peripheral surfaces of both ends of the mandrel 18, and when the first fitting portion and the second fitting portion are connected to each other, The groove of the two mandrels forms the groove 26 that forms the thick portion of the belt. When forming the thick portion, the mandrel 18
Or the resin extrusion speed of the extruder is increased to completely fill the concave groove with the resin and form a thick portion. When the obtained continuous tubular body 7 is cut at the joint portion position of the mandrel, the guide portion 14 is formed in the thick portion. In the example of FIG. 4, FIG.
The guide portion 14 having the shape shown in (a) is formed.

FIG. 5 shows an example in which a concave line is formed only on one end of the mandrel 18. In the example of this figure, mandrel 1
When the continuous tubular body 7 formed on the outer peripheral surface of 8 is cut at the C1 and C2 positions, the portion formed by the concave groove 26 serves as a guide portion, and after cooling, it is easily pulled out from the mandrel 18 by pulling it out in the X direction. It can be removed.

In the example shown in FIG. 4, in order to remove the belt from the mandrel 18, it is necessary for the belt to spread a little in the radial direction at the guide portion. In the system shown in FIG. 5, it is easy to remove the belt made of a rigid resin.

FIG. 6 is an example showing a manufacturing method suitable for manufacturing the seamless resin belt having two guide portions slightly inside the end portions illustrated in FIG. 3C. Mandrels 18A each having a concave line on the outer peripheral surface of both ends
And a mandrel 18B are provided with a ring body 17 having concave lines on the outer peripheral surfaces of both ends thereof, and the concave groove 2 forming a guide portion by the concave line of the ring body 17 and the concave line of the mandrel 18
6A and 26B are formed. With such a configuration, even when the mold release becomes difficult when the high-rigidity resin material is used and the mandrel shown in FIG. 4 is used, the mold release becomes easy.

It is also possible to manufacture the belt without using a mandrel, and the resin discharge speed of the extruder is increased or the take-up speed of the continuous tubular body is decreased depending on the conditions for forming the belt flat portion 12. Alternatively, or by performing both operations at the same time, the thick portion can be easily formed.

A preferable material for the resin for the seamless resin belt of the present invention is basically a resin composition containing a thermoplastic resin as a main raw material, and a resin having high rigidity and a thermoplastic elastomer can also be used. Specifically, polyethylene (high density, medium density, low density, linear low density), polyolefin or olefin copolymer such as propylene ethylene block or random copolymer, styrene / butadiene / styrene block copolymer, or Hydrogenated derivative, polyamide, polyamideimide, polyacetal, polyarylate, polycarbonate, polyphenylene ether, modified polyphenylene ether, polyimide, liquid crystalline polyester, polyester resin such as polyethylene terephthalate or polybutylene terephthalate (PBT), polysulfone, polyether sulfone ,
Polyphenylene sulfide, polybisamide triazole, polyetherimide, polyether ether ketone, polyvinylidene fluoride or polyvinyl fluoride, ethylene tetrafluoroethylene copolymer, polychlorotrifluoroethylene, tetrafluoroethylene hexafluoropropylene copolymer, tetra Fluorine-based resins such as fluoroethylene perfluoroalkyl vinyl ether copolymers, alkyl acrylate copolymers, polyester ester copolymers, polyether ester copolymers,
Examples include polyether amide copolymer and polyurethane resin, which may be used alone or in combination of two or more kinds.

The seamless resin belt produced by the production method of the present invention is semi-conductive, that is, 10 in terms of volume resistivity.
It is preferably ⁴ to 10 ¹² Ω · cm. Further, the more uniform the electrical properties, particularly the volume resistivity and the surface resistivity, the more preferable, and the ratio of the maximum value and the minimum value of the resistance values measured by applying the electrodes to the belt is preferably 10 or less. In order to impart conductivity to the seamless resin belt, it is preferable to add a conductive filler. As the conductive filler, acetylene black, furnace black, carbon black such as channel black, graphite, carbon fiber, metal powder, conductive metal oxide,
Examples thereof include organic metal oxides, organic metal compounds, and conductive polymers. One kind selected from these or two or more kinds may be used in combination if necessary.

Instead of the conductive filler, or together with the conductive filler, an ion conductive additive or antistatic agent may be added. No. 4 known as an ion conductive additive
A quaternary ammonium salt, an alkali metal salt, a phosphate or the like can be used. Specifically, LiClO ₄ , perchlorate such as NaC1O ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , Li
Borofluoride such as BF ₄ , NaSCN, KSCN
Such as thiocyanate, halogen salt such as NaC1, lauryl trimethyl ammonium, stearyl trimethyl ammonium, octadecyl trimethyl ammonium, dodecyl trimethyl ammonium, alcohol modified fatty acid salt, sulfate, sulfonate, ethosulfate salt, etc.
Anions such as cationic surfactants that are secondary ammonium salts, aliphatic sulfonic acids, higher alcohol sulfate ester salts, higher alcohol ethylene oxide addition sulfate ester salts, higher alcohol phosphate ester salts, higher alcohol ethylene oxide addition phosphate ester salts, etc. Examples thereof include surfactants, amphoteric surfactants such as various betaines, and antistatic agents such as higher alcohol ethylene oxide, polyethylene glycol fatty acid esters, nonionic surfactants such as polyhydric alcohol fatty acid esters.

When the volume resistivity of the resin material itself is within the required resistance value range, it is not necessary to add the conductive filler.

In addition to the conductive filler, it is also a preferred embodiment to add other fillers if necessary. Examples of such fillers include calcium carbonate (heavy,
(Soft), talc, mica, silica, alumina, aluminum hydroxide, magnesium hydroxide, barium sulfate, zinc oxide, zeolite, wollastonite, diatomaceous earth, glass beads, bentonite, montmorillonite, hollow glass spheres, graphite, disulfide Molybdenum, titanium oxide, wood powder,
Examples include fillers such as rice husks, organic metal compounds, and organic metal salts.

It is also a preferred embodiment to add various additives to the seamless resin belt of the present invention.
Examples of such additives include antioxidants (phenol-based, sulfur-based, etc.), lubricants, various organic / inorganic pigments, ultraviolet absorbers, dispersants, neutralizing agents, foaming agents, plasticizers, copper damage prevention. Examples include agents, cross-linking agents, flow improvers and the like.

It is a preferred embodiment that the surface of the seamless resin belt of the present invention is provided with a lubricating surface layer if necessary.

By providing such a lubricating surface layer, effects such as an improvement in toner transfer efficiency and an improvement in cleaning can be obtained. Known materials can be used as the material for the lubricating surface layer, and examples thereof include a polyurethane resin layer containing fluorine and a coating layer containing fine polytetrafluoroethylene powder.

[0033]

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating a method of extrusion molding a continuous cylindrical body of a belt raw material using an extruder.

FIG. 2 is a cross-sectional view of an example of a seamless resin belt in which a guide portion is provided near the end portion

FIG. 3 is a cross-sectional view showing an example of the shape of a thick portion forming a guide portion.

FIG. 4 is a cross-sectional view showing an example in which a plurality of mandrels are fitted and continuously provided to form a belt.

FIG. 5 is a cross-sectional view illustrating the shape of a groove formed on the outer peripheral surface of the mandrel end and a guide formed by the groove.

FIG. 6 is a cross-sectional view showing another example of the shape of the groove formed on the outer peripheral surface of the end of the mandrel and the guide formed by the groove.

FIG. 7 is a schematic diagram showing the configuration of an image forming apparatus using an intermediate transfer belt.

[Explanation of symbols]

1 extruder 7 Continuous tubular body 10 belts 12 Flat belt 14 Guide part

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // B29K 101: 12 B29K 101: 12 B29L 29:00 B29L 29:00 F term (reference) 2H171 FA07 FA09 FA10 FA15 GA04 GA15 LA16 PA04 QA02 QA09 QA13 QA24 QA25 QC05 QC09 SA32 UA03 UA05 UA07 UA22 XA03 XA16 2H200 FA04 FA13 GA23 GA24 JB07 JB40 JB43 JB45 JB46 JC04 JC10 JC13 JC15 JC16 LA25 LC03 MA04 MA11 MA12 MA13 MA14 MA20 MB04 4F207 AA04 AA28 AA29 AG08 AG16 AH33 AR08 AR12 AR14 KA01 KA17 KL88 KW23

Claims (2)

[Claims] 1. A seamless resin belt comprising: an extrusion step of continuously extruding a thermoplastic resin from an extruder to form a continuous cylindrical body; and a cutting step of cutting the continuous cylindrical body in a longitudinal direction to form a belt. In the manufacturing method, the extrusion step is a flat belt portion forming step of extruding the molten thermoplastic resin at a constant discharge speed and pulling the continuous cylindrical body at a constant take-up speed, and an increase in the discharge speed and a take-up speed. A thick portion forming step of forming a thick portion by performing at least one of the reduction, and the cutting step includes cutting the continuous cylindrical body at or near the thick portion to guide at least one end portion. A method for producing a seamless resin belt, which is a seamless belt having a portion. 2. The extruding step includes a first fitting portion at one end,
A plurality of cylindrical mandrels each having a second fitting portion at the other end are linearly fitted by fitting the first fitting portion of one mandrel to the second fitting portion of another mandrel. The mandrel is continuously provided and supplied to the resin extruding part of the extruder to form the continuous cylindrical body on the outer peripheral surface of the mandrel, wherein the mandrel has a groove formed on at least one end of the outer periphery thereof. The seamless resin belt according to claim 1, wherein a groove is formed on the outer periphery of the joint by the groove when the thick grooves of the belt can be formed by the groove. Method.