JP2004233978A - Semiconductor seamless belt and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor seamless belt which is low in compression modulus in a thickness direction, makes a nip width at the time of transferring sufficiently obtainable and is small in elastic deformation by tensile stress during belt driving. <P>SOLUTION: The semiconductor seamless belt laminated with a thermoplastic elastomer on the outside surface side of a base material made of a high-rigidity resin having a Young's modulus of ≥100 MPa is provided. The semiconductor seamless belt is manufactured by the manufacturing method of connecting two units of extruders consisting of at least first extruder and second extruder to one set of dies, extrusion molding a base material layer of the high-rigidity resin having a Young's modulus of ≥100 MPa from the first extruder in the dies, extruding the thermoplastic elastomer layer from the second extruder onto the outside surface of the base material layer to form a laminated tube, and cutting the laminate tube. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to an electrophotographic image forming apparatus such as a color copying machine, a laser beam printer, a facsimile, and an OA apparatus having a combination of these functions using a plurality of types of color toners using the basic principle of electrophotography. The present invention relates to a semiconductive seamless belt suitable for an intermediate transfer belt, a transfer belt and the like to be used, and a method for manufacturing the same. The semiconductive seamless belt of the present invention can also be used for a transfer belt or the like used in a process of transferring a toner image formed on an image carrier such as a photoreceptor or a transfer belt onto plain paper or the like. it can.

  In an electrophotographic image forming apparatus, a multi-color toner is used in a color image forming apparatus, in order to provide a transfer function and a paper feeding function to sharpen a transferred image and reduce the number of parts. For the purpose of forming a full-color image, a transfer belt and an intermediate transfer belt, which are semiconductive seamless belts, are being adopted.

  An image forming apparatus using an electrophotographic method is a laser light that modulates an image signal by forming a uniform charge on an image carrier composed of a photoconductor composed of an inorganic photoconductive material or an organic photoconductive material. After forming an electrostatic latent image with a developing device, the electrostatic latent image is developed with a charged toner to form a visualized toner image, and the toner image is directly transferred or via an intermediate transfer member. The apparatus includes a transfer device that obtains a required reproduced image by transferring the image to a recording medium such as paper, and a fixing device that fixes the reproduced image.

  As a transfer belt used in such a transfer device, an elastic belt and a resin belt are known.

  Examples of the resin constituting the resin belt include polyvinylidene fluoride (PVDF) (Patent Document 1 and the like), polycarbonate (PC) (Patent Document 2), and a blend of ethylene-tetrafluoroethylene copolymer (ETFE) and PC Thermoplastic resins such as resins are known, and a conductive or semi-conductive seamless belt in which these resins are blended with carbon black or the like as a conductive filler has been proposed. A transfer belt using a thermosetting polyimide resin as a resin having particularly excellent mechanical properties is also known (for example, Patent Document 3).

On the other hand, elastic belts are also known (Patent Documents 4 and 5).
JP-A-5-200904 JP-A-6-95521 JP-A-63-31263 JP-A-4-29276 JP-A-9-131765

  However, since the resin belts described in Patent Documents 1 to 3 have high rigidity not only in the circumferential direction and the width direction but also in the thickness direction, the belt is compressed by the pressing force of the roll during the secondary transfer. Since the deformation is small and the nip width in transfer cannot be sufficiently obtained, there is a problem that image quality defects are likely to occur.

  In addition, if foreign matter is mixed in the toner and is caught between the photosensitive member and the resin belt, the photosensitive member and the resin belt are both high in hardness, so that at least one surface is damaged by the foreign matter and the life is shortened. There is also the problem of causing

  On the other hand, the elastic belts described in Patent Documents 4 and 5 have an advantage that the compression elastic modulus in the thickness direction is lower than that of a thermoplastic resin having high rigidity and a sufficient nip width can be obtained at the time of transfer. Has the advantage that it does not damage the photoreceptor even if foreign matter is mixed into it, but it causes elongation and deformation due to tensile stress when the belt is driven, and in color images, image defects due to misalignment of the toner are also likely to occur There is a problem that.

  An object of the present invention is to provide a semiconductive seamless belt and a surface lubricating layer which have a low compression elastic modulus in the thickness direction, a sufficient nip width at the time of transfer, and a small elongation deformation due to tensile stress at the time of driving the belt. Another object of the present invention is to provide a method for manufacturing a semiconductive seamless belt whose process is simple.

  The semiconductive seamless belt of the present invention is characterized in that a thermoplastic elastomer layer is laminated on the outer surface side of a base made of a highly rigid resin having a Young's modulus of 100 MPa or more.

  The semiconductive seamless belt having such a configuration is a semiconductive seamless belt that has a low compression elastic modulus in the thickness direction, a sufficient nip width at the time of transfer, and a small elongation deformation due to tensile stress at the time of driving the belt. is there.

    If the Young's modulus of the base material constituting the semiconductive seamless belt of the present invention is less than 100 MPa, the elongation deformation due to the tensile stress at the time of driving the belt increases, and the image accuracy decreases. The base material preferably has a Young's modulus of 4000 MPa or less. If the Young's modulus of the base material exceeds 4000 MPa, the workability at the time of mounting and replacement is poor because the base material is too hard, the brittleness of the base material increases, the base material is easily cracked, and the surface is easily damaged. Cause problems.

Semi-conductive means that the volume resistivity is in the range of 10 ⁴ to 10 ¹² Ω · cm. When the volume resistivity of the belt is in the semiconductive range, the belt can be used as a transfer belt having a predetermined transfer performance. The volume resistivity of the belt is appropriately set to a predetermined value selected from the above range according to the specifications of the model used. Regarding the volume resistivity of the belt, it is preferable that the variation of the value measured by applying an electrode is 10 or less in the ratio of the maximum value to the minimum value. The volume resistivity is measured for the entire belt, and the individual volume resistivity of the substrate and the thermoplastic elastomer layer is not particularly limited.

  In the above-described seamless belt, the thermoplastic resin constituting the base material is preferably a polyimide resin or a polyester resin.

  By using such a resin, a seamless belt having a base layer having excellent durability and dimensional stability can be obtained.

  In the seamless belt, it is preferable that the high-rigidity resin is a polyester-based resin, and the thermoplastic elastomer is a polyester-based thermoplastic elastomer.

  When a high-rigidity resin and a thermoplastic elastomer are combined as described above, the two layers are firmly bonded without providing an adhesive layer when laminated by a co-extrusion method to form a seamless belt. A belt can be manufactured.

  It is not clear why the combination of such resins causes the high-rigidity resin layer and the thermoplastic elastomer layer to adhere firmly, but when they are melted and co-extruded and laminated, the transesterification reaction occurs at the interface between the two layers. It is presumed that this is also a cause.

  The polyester-based thermoplastic elastomer does not need to have all of the constituent components having a polymer constituent bond in which an ester bond is used, and may be a mixture of a polyester polymer component and other components, such as a mixture of a rubber material and a composite such as a polymer alloy. There may be.

  The polyester-based resin means a resin including a polyester resin, a blended resin of a polyester resin and another resin, a polymer alloy resin, and the like.

  In the seamless belt described above, it is preferable that the polyester resin forming the base material is a resin containing at least one of polyalkylene terephthalate resin and polyalkylene naphthalate resin and a polycarbonate resin.

  By using such a resin, it has a base layer having excellent durability and dimensional stability, and when a polyester-based thermoplastic elastomer is used as the thermoplastic elastomer, a co-extrusion molding method provides a half-layer having excellent interlayer adhesion. A conductive seamless belt can be obtained.

  The thickness of the substrate is preferably 100 to 300 μm, and the thickness of the entire belt is preferably 0.2 to 2 mm.

  The above-described semiconductive seamless belt preferably further has a lubricating layer on the outer surface of the thermoplastic elastomer layer.

  By providing the lubricating layer on the surface, the cleaning property of the toner prepared for the next transfer after transfer is further improved.

The method for producing a semiconductive seamless belt according to the present invention includes an extruder equipped with a head having a mandrel supply unit, a thermoplastic elastomer supply unit, and a die unit for forming the thermoplastic elastomer layer on the outer peripheral surface of the mandrel. use,
A base material supply step of mounting a cylindrical high rigid resin base material on the outer peripheral surface of the mandrel and supplying the head to the head, forming a thermoplastic elastomer layer on the outer peripheral surface of the base material, and forming a high rigid resin material. It has a thermoplastic elastomer layer laminating step of forming a laminated structure having a thermoplastic elastomer layer on the outer surface side of the base material.

  According to the manufacturing method having such a configuration, a semiconductive seamless belt having a low compression elastic modulus in the thickness direction, a sufficient nip width at the time of transfer, and a small elongation deformation due to tensile stress at the time of driving the belt is manufactured. can do.

  As a multilayer technology of a belt in which an elastic layer is laminated on a resin belt substrate, a technology of laminating different material layers by coating on the surface of a belt-shaped substrate is generally used. When an elastic layer is formed by painting, two or more painting steps are required to further provide a lubricating layer on the surface, and in the production of a semiconductive seamless belt having a surface lubricating layer, the process becomes complicated, Not preferred. According to the present invention, it is sufficient to provide a coating step when forming a necessary surface lubrication layer, and it is not necessary to provide two or more coating steps, and a semiconductive seamless belt can be manufactured in a simple step. Can be.

  The semiconductive seamless belt having the configuration of the present invention has a low compressive elasticity in the thickness direction, a sufficient nip width at the time of transfer, and a small semiconductive seamless belt with small elongation deformation due to tensile stress at the time of driving the belt. It is a belt.

  Further, according to the manufacturing method having the configuration of the present invention, a semi-conductive seamless material having a low compression elastic modulus in the thickness direction, a sufficient nip width at the time of transfer, and a small elongation deformation due to tensile stress at the time of driving the belt. Belts can be manufactured. In particular, when a lubricating layer is further provided on the surface, it is not necessary to provide two or more coating steps, and a semiconductive seamless belt can be manufactured by a simple step.

  In the seamless belt of the present invention, as the thermoplastic resin suitable for the base material layer, a resin having a Young's modulus of 100 MPa or more when formed into a film can be used without limitation. Specific examples of the resin include PET, PBT, polypropylene terephthalate, polyalkylene terephthalate resin such as polyester of 1,4-cyclohexane dimethanol and terephthalic acid, polyethylene naphthalate, polypropylene naphthalate, 1,4-cyclohexane dimethanol Polyalkylene naphthalate resin such as polyester with naphthalenedicarboxylic acid, polyimide resin, polycarbonate resin, polyphenylene oxide, polyphenylene sulfide, PEEK, aramid resin, polyurethane resin, fluorine-based resin such as PFA, and these resins. Examples thereof include resin blend resins and polymer alloys.

  Among these, as described above, it is preferable to use a resin containing at least one of a polyimide or polyester resin, particularly a polyalkylene terephthalate resin and a polyalkylene naphthalate resin, and a polycarbonate resin. The mixing ratio of the mixed resin of PC and PBT is preferably PC / PBT = 5/95 to 40/60 (weight ratio) in terms of physical characteristics.

  As the thermoplastic elastomer (TPE), a known thermoplastic elastomer can be used without particular limitation. Specifically, polyester TPE, polyurethane TPE, polyolefin TPE, polystyrene TPE, polyamide TPE, ionomer TPE, diene TPE, polyvinyl chloride TPE, polyvinyl chloride / polyurethane polymer alloy TPE, thermoplastic Examples thereof include a mixture of a resin and a rubber. It is also possible to use a thermoplastic elastomer obtained by mixing or dispersing a rubber in these thermoplastic elastomers in the form of fine particles. These TPEs can be used alone, and if necessary, two or more may be used in combination.

  Among the thermoplastic elastomers, when using a resin containing at least one selected from the group consisting of polyester resins, particularly polyalkylene terephthalate resins and polyalkylene naphthalate resins, and a polycarbonate resin as the base material, The use of polyester-based TPE is preferred.

  The hardness of the thermoplastic elastomer is preferably 60 or less in Shore A hardness. If the hardness is too high, the compression elastic modulus in the thickness direction increases, and a sufficient nip width during transfer cannot be obtained. The hardness of the thermoplastic elastomer is usually 30 or more in Shore A hardness.

  In order to adjust the above-mentioned base material and thermoplastic elastomer to predetermined electric characteristics, particularly, volume resistivity to a predetermined value, a conductive material is added as necessary. As the conductive material, a known conductive material can be used without limitation. Specifically, metal materials such as silver powder, copper powder, nickel powder, etc., metal oxides such as tin oxide and indium oxide, inorganic materials such as mica coated with metal, carbon compounds such as carbon black and graphite, carbon fiber, An ionic conductive material such as lithium perchlorate and ammonium thiocyanate is exemplified. These conductive materials are used in combination of two or more as necessary.

  Among the above-mentioned conductive materials, the use of carbon black is particularly preferable because a reinforcing effect is also obtained. As the carbon black, specifically, EC (Extra Conductive) carbon such as Ketjen Black EC, ECF (Extra Conductive Furnance) carbon, SCF (Super Conductive Furnance) carbon, CF (Conductive Furnance) carbon, acetylene black, SAF , ISAF, HAF, FEF, GPF, SRF, FT, MT and the like. These may be used alone or in combination of two or more.

  It is a preferred embodiment to add additives such as a processability improver, other fillers, a stabilizer, an antioxidant, and a dispersion improver to the resin constituting the base layer and the thermoplastic elastomer, if necessary.

  An adhesive layer may be provided between the base material layer and the thermoplastic elastomer layer. When the semiconductive seamless belt of the present invention is manufactured by laminating a base material layer and a thermoplastic elastomer layer in a molten state and performing simultaneous extrusion, delamination can occur without providing an adhesive layer. It is preferable to use a belt having no laminated structure, and a combination of a resin constituting a base material layer and a resin constituting a thermoplastic elastomer having excellent adhesive strength by lamination in a molten state is selected. Specifically, a polyester resin containing at least one of a polyalkylene terephthalate resin and a polyalkylene naphthalate resin and a polycarbonate resin is used as a base layer constituent resin, and a polyester TPE is used as a thermoplastic elastomer layer constituent resin. It is preferable to use a polyurethane-based TPE or an ionomer-based TPE because the adhesive strength in lamination in a molten state is excellent.

  The material constituting the surface lubricating layer provided as needed is, for example, a resin layer having a lubricating functional group, or a resin layer containing a lubricating material, and the resin layer having a lubricating functional group has a fluorine group. An acrylic resin layer is exemplified, and as the resin layer containing a lubricating material, polyurethane resin containing a lubricating material such as polytetrafluoroethylene fine powder, boron nitride fine powder, molybdenum disulfide, graphite, acrylic resin Resins and the like are exemplified. These are preferably used as paints, and are preferably applied to a thickness of about 5 to 50 μm on the thermoplastic elastomer layer to form a surface lubricating layer (surface lubricating layer forming step).

  A preferred embodiment of a method for manufacturing a semiconductive belt according to the present invention will be described with reference to the drawings. FIG. 1 shows a manufacturing apparatus using an extruder equipped with a crosshead. The crosshead is mounted on an extruder, and is a typical example of a head including a mandrel supply unit, an elastic body composition supply unit, and a die unit that forms the elastic body composition layer on the outer peripheral surface of the mandrel. It is an example.

  As shown in FIG. 1A, the extruder 1 includes a screw portion 17, a motor 6 for driving the screw, and a crosshead 8 provided at the tip of the screw portion 17. FIG. 1B is a perspective view showing the crosshead 8. A mandrel 5 on which a high-rigidity resin base material formed in a seamless belt shape is mounted in a straight line is fed into the crosshead 8 in the direction of the arrow, and the heat supplied from the hopper 15 in the form of pellets or the like is supplied. A high rigidity in which the thermoplastic elastomer is continuously coated with a predetermined thickness on the outer peripheral surface of the base material mounted on the mandrel 5 at a die portion (not shown) in the crosshead 8 in a molten state, and a thermoplastic elastomer layer is laminated. The mandrel 5a carrying the resin base material is discharged. FIG. 1B shows an example in which the continuously provided mandrels 5 are supplied and sent out in the horizontal direction, but the present invention is not particularly limited, and a configuration in which the mandrels 5 move in the vertical direction may be used.

  FIG. 2 is a cross-sectional view of the mandrel 5 having the outer periphery coated and mounted with the base material 14. The mandrel is provided in series and can be supplied to the head, and has a concave portion and a convex portion at the longitudinal end. That is, a convex fitting portion 10 is formed on one end of the mandrel 5 and a concave fitting portion 12 is formed on the other end, and the convex fitting portion 10 of one mandrel 5 is connected to another. By being fitted to the concave fitting part 12 of the mandrel, it is formed so as to be able to be connected linearly. A mandrel 5 coated and mounted on the outer periphery of the base material 14 is connected to the extruder, and a thermoplastic elastomer layer is formed by lamination.

  The surface of the cylindrical tube-shaped substrate 14 may be untreated, or may be subjected to a corona discharge treatment or a primer treatment in order to improve the adhesion to the thermoplastic elastomer used.

  The mandrel 5 covered and mounted with the base material 14 shown in FIG. 2 may be separately formed into a tube on the mandrel 5 and mounted with the base material 14 cut to a predetermined length. It is a more preferable embodiment that the resin is used as it is after being extruded on a mandrel because the process is simple.

  In FIG. 3, the mandrel 5 is connected and supplied to a thermoplastic resin extruder 40 having a crosshead similar to that shown in FIG. 1, and the thermoplastic resin supplied in the form of pellets from the hopper 42 is supplied. The example in which the mandrel 5k on which the base material 14 is mounted by extruding the mandrel 5 supplied by the head 44 is shown. The mandrel 5k on which the base material 14 has been formed may be cut at the connecting portion D and then provided to the next step, or a plurality of the mandrel 5k may be connected and cut to form the thermoplastic elastomer laminating step shown in FIG. May be served. In FIG. 3, the mandrel 5 is supplied so as to move vertically from above to below.

  FIG. 4 shows an apparatus suitable for producing a belt using two extruders 21 and 23 and using a highly rigid thermoplastic resin as a base material. A first extruder 21 for extruding a high-rigidity thermoplastic resin and a second extruder 23 for extruding a thermoplastic elastomer are all connected to a head 25. The thermoplastic resin discharged from the extruder 21 is supplied to the outer peripheral surface of the mandrel 2 to the head 25 through a flow path 27 leading to the entire periphery of the mandrel as shown in FIG. The base material layer 33 is formed by coating to a predetermined thickness. Next, a thermoplastic elastomer is supplied from the second extruder 23 and is laminated to a predetermined thickness on the outer peripheral surface of the base material layer 33 through the flow path 29 leading to the entire circumference of the mandrel at the second die 28 to form a laminated structure. A semiconductive seamless belt is formed.

  The cutting is performed at a cutting position C corresponding to the joining position P of the mandrel, for example, using a heat cutter.

Hereinafter, examples and the like that specifically show the configuration and effects of the present invention will be described.
(Example 1)
As a thermoplastic elastomer, 30 parts by weight of Carbon Black Seast 3 (Tokai Carbon) is added to 100 parts by weight of a polyester-based thermoplastic elastomer (rubber-containing type) Primaloy A1500 (Mitsubishi Chemical) and mixed to give a volume resistivity of 2 × 10 ¹⁰ Ω. -A semiconductive thermoplastic elastomer adjusted to cm was used.

Polycarbonate / polybutylene terephthalate = 25/75 (weight ratio) as a high-rigidity resin substrate, volume resistivity adjusted to 2 × 10 ¹⁰ Ω · cm by adding carbon black, thickness 130 μm, circumference 473 mm, width 276 mm A cylindrical resin base material having an outer diameter of 150 mm and a width of 280 mm is mounted on a mandrel which can be connected in a longitudinal direction and has a configuration shown in FIG. The mixture was supplied to the extruder provided in the direction of the arrow to form a laminate having the above-mentioned semiconductive polyester-based thermoplastic elastomer layer having a thickness of 0.3 mm on the surface.

The obtained laminate was cut into a width of 266 mm to obtain a semiconductive seamless belt having a volume resistivity of 5 × 10 ¹⁰ Ω · cm as a whole.

A lubricating layer was formed on the belt surface by applying Dye Latex GLS-213F (Daikin Industries) so that the dry coating film thickness became 20 μm.
(Example 2)
A semiconductive seamless belt was produced in the same manner as in Example 1, except that a semiconductive polyimide resin belt was used as the high-rigid resin base material.
(Comparative Examples 1 to 3)
For comparison, the same evaluation was performed using a polyimide resin belt currently used as Comparative Example 1, a polycarbonate resin belt as Comparative Example 2, and a rubber belt as Comparative Example 3. Table 1 shows the evaluation results.
<Evaluation>
The belt obtained in Examples 1 to 4 was mounted on a commercially available color printer LP-3000C (manufactured by Epson Corporation), an image forming test was performed, and the obtained image was observed using a magnifying lens, and the toner was misaligned. And the image quality was evaluated. The evaluation results are shown in Table 1. Regarding the positional deviation of the toner, も の indicates that there was almost no positional deviation, ◎ indicates that there was no positional deviation, and X indicates that the positional deviation was observed. Also, those with good image quality were indicated by ◎, and those with poor image quality were indicated by x.

表１の結果より、本発明の半導電性シームレスベルトを転写ベルトとして使用した場合には、優れた画像が形成されることが分かる。これに対して熱可塑性エラストマー層を有しない高剛性樹脂のみのベルトはトナーの位置ズレは起きないが、画質が満足できるものではなく、高剛性樹脂製の基材を有しないゴムベルトはトナーの位置ズレに問題を有するものであった。

From the results in Table 1, it can be seen that excellent images are formed when the semiconductive seamless belt of the present invention is used as a transfer belt. On the other hand, a belt made of only a high-rigidity resin having no thermoplastic elastomer layer does not cause toner misalignment, but the image quality is not satisfactory, and a rubber belt having no high-rigidity resin base material has a toner position deviation. There was a problem with the displacement.

The figure which showed the example of the manufacturing apparatus of the belt which forms the thermoplastic elastomer layer using the extruder provided with the crosshead Sectional view exemplifying the configuration of a mandrel that can be installed linearly in the length direction and is covered with a high-rigidity resin belt. Diagram illustrating a process of forming a thermoplastic high-rigid resin base material on an outer peripheral surface of a mandrel by extrusion molding. Schematic diagram showing an apparatus suitable for manufacturing a belt using a high-rigidity thermoplastic resin as a base material using two extruders. The figure which showed the example of the structure of the head of the manufacturing apparatus of FIG.

Claims (6)

A semiconductive seamless belt, characterized in that a thermoplastic elastomer layer is laminated on the outer surface side of a substrate made of a highly rigid resin having a Young's modulus of 100 MPa or more. The semiconductive seamless belt according to claim 1, wherein the high-rigidity resin is a polyimide resin or a polyester-based resin. The semiconductive seamless belt according to claim 2, wherein the high-rigidity resin is a polyester-based resin, and the thermoplastic elastomer is a polyester-based thermoplastic elastomer. The semiconductive seamless belt according to claim 2 or 3, wherein the polyester resin is a resin containing at least one of a polyalkylene terephthalate resin and a polyalkylene naphthalate resin and a polycarbonate resin. The semiconductive seamless belt according to any one of claims 1 to 4, further comprising a lubricating layer on the outer surface of the thermoplastic elastomer layer. Using an extruder equipped with a head provided with a mandrel supply section, a thermoplastic elastomer supply section and a die section for forming the thermoplastic elastomer layer on the outer peripheral surface of the mandrel,
A base material supply step of mounting a cylindrical high rigid resin base material on the outer peripheral surface of the mandrel and supplying the head to the head, forming a thermoplastic elastomer layer on the outer peripheral surface of the base material, and forming a high rigid resin material. A method for producing a semiconductive seamless belt, comprising a thermoplastic elastomer layer laminating step of forming a laminated structure having a thermoplastic elastomer layer on the outer surface side of a substrate.

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