JP2006098851A - Endless belt for electrophotographic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an endless belt which can be made inexpensively, has improved adhesion of each layer, has excellent durability, and is free from a crack or peel-off even after long-time use. <P>SOLUTION: The endless belt for an electrophotographic device consists of at least two or more layers composed of different materials. (i) At least one of the layers are chiefly composed of thermoplastic resins. (ii) The endless belt for electrophotography is obtained by a melt forming process. (iii) The adhesive strength between the two adjacent layers shows 4 or more points by a JIS K 5400 X-cut tape method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an endless belt used in an electrophotographic apparatus.

  Conventionally, a transfer end member, an intermediate transfer member, an electrophotographic photosensitive member, a fixing member, etc. used in an electrophotographic apparatus such as a copying machine or a laser beam printer have a flexible endless belt shape in addition to a rigid drum shape. Things (endless belts for electrophotographic devices) are used.

  In recent years, full-color electrophotographic apparatuses have been put into practical use, and the number of produced units has been increasing year by year. Accordingly, the demand for intermediate transfer belts, transfer conveyance belts and the like has also increased.

  Various materials for these endless belts have been proposed.

  For example, an example in which a thermosetting rubber is used as an endless belt for an electrophotographic apparatus is known (for example, see Patent Document 1). When rubber was used, a process called vulcanization was required, requiring a lot of energy and time, leading to an increase in cost. Further, rubber has a low elastic modulus. For example, when used as an intermediate transfer belt, there is a problem in that the belt itself is stretched and color misregistration occurs. In addition, the creep resistance is poor, and when the belt is stretched on a roller, the belt gradually stretches, loosens, and cannot be used. Furthermore, since it was inferior also in abrasion resistance, the surface was shaved and it was inferior in durability.

  In addition, an example in which a thermosetting resin is used as an endless belt for an electrophotographic apparatus is known (for example, see Patent Document 2). Here, a thermosetting polyimide is illustrated. Thermosetting resins have the advantages of higher elastic modulus, excellent creep resistance, and wear resistance than the rubber materials described above. However, the material itself is very expensive, and it is necessary to dissolve the resin or resin precursor in an organic solvent or acid before molding. To mold these resins, centrifugal molding or dipping However, these methods have a problem that it takes time to form and it is difficult to reduce manufacturing costs. In addition, when a non-soluble filler is added to give desired properties, it leads to poor dispersion such as sedimentation or agglomeration, lack of uniformity of the belt, and tends to cause partial strength reduction and resistance variation. There was also a problem.

  As described above, when thermosetting rubber or resin is used as a material, there are many problems. As a means for solving these problems, a method using a material made of a thermoplastic resin has been proposed.

  As the thermoplastic resin, for example, a resin obtained by blending a conductive filler with polycarbonate (PC), polyethylene terephthalate (PET) or the like has been used. However, polycarbonate is inferior in bending fatigue resistance, and when used for a long period of time, there is a problem that it cracks and eventually breaks, resulting in poor durability. Further, polycarbonate (PC) and polyethylene terephthalate (PET) have high polarity and poor release properties from the toner. This often causes problems such as toner filming.

In view of this, a proposal has been made to achieve both toner releasability and mechanical strength by using a fluororesin for the surface layer and a resin having excellent mechanical strength for the base layer. For example, an example in which polyethylene naphthalate and polyvinylidene fluoride are thermally fused is known (see, for example, Patent Document 3). However, since a non-adhesive fluororesin is used as the surface layer, there is a drawback in that the adhesion to the base layer is poor, and therefore there is a problem that floating or peeling occurs between the layers when used for a long time. It was.

  As described above, many endless belts having a multi-layer structure based on functional separation have been proposed in which the surface layer has releasability from toner and the base layer has mechanical properties.

  Thus, recently, along with the improvement in image quality and functionality of electrophotographic apparatuses, endless belts used therefor are also required to have higher functionality and higher durability as well as lower prices. In order to satisfy the demand for higher functionality, the endless belt has a limit in a single layer configuration, and the function is separated in each layer by adopting a multilayer configuration, thereby achieving higher functionality as a whole. For example, as described above, in the case of a belt that has both a releasability with toner and mechanical properties, or a belt that contains a material containing a material that is contaminated with the photoreceptor, a barrier layer that does not further contain on the surface As another example, functional separation such as preventing the leakage by providing a surface layer on a belt that easily leaks due to discharge is provided.

  The following proposals have been made as an example of a multilayer belt.

  For example, as a multilayer belt configuration and manufacturing method, it is known that a resin is dissolved in a solvent and coated by dipping to form each layer (see, for example, Patent Document 4).

  In a system using a solvent, only a resin that is soluble in a specific solvent can be used, and usable materials are limited. In particular, in the case of multi-layering by dipping, the solvent of the layer to be dipped may dissolve the material of the layer already provided, and the desired characteristics cannot be obtained, and contamination of the dipping material (contamination) ). In addition, it takes a lot of time to dry the solvent, and a large amount of solvent is used, so a device for recovering it is also required, resulting in a large-scale facility, a lot of capital investment and wide installation. Space was required, leading to increased costs. Furthermore, there has been a concern that the residual solvent in the product may contaminate the photoreceptor or adversely affect other parts that come into contact with the belt.

  By the way, when the endless belt has a multilayer structure, the adhesion between the layers greatly affects the durability. As described above, when a fluororesin is used, there is a problem that sufficient adhesion cannot be obtained.

  In order to solve this problem, it has been proposed that an adhesive layer is provided between the layers using an adhesive, a primer, or the like. However, adhesives, primers, and the like require an application process, and if they are not evenly applied with a uniform thickness, the adhesiveness may be lowered, or the function as an endless belt may be impaired. Further, for example, when a solvent-based adhesive is used, the adhesive layer is sandwiched between one adjacent layer and the other layer, so that the solvent does not evaporate and remains. However, there is a problem that it gradually oozes out and invade parts that come into contact with the endless belt. In addition, there are problems that air bubbles are involved at the time of applying the adhesive, resulting in an image failure, distortion due to curing shrinkage, and wrinkles.

  As a method for solving the above-described problems and improving the adhesion without using an adhesive, it is known to treat the surface of a substrate (see, for example, Patent Documents 5 and 6). However, these methods require a processing step separately from the belt forming step, which increases the cost due to an increase in the number of steps.

  In addition, although it is described that these treatments only need to be carried out, it is very difficult to uniformly treat a cylindrical object when actually carrying out the treatment, and the processing is uneven. As a result, unevenness was caused in the adhesion, and partial peeling or lifting was likely to occur. Also, distortion and warpage were likely to occur. Variations in processing, too hard processing, damages the base layer and sometimes causes pinholes. In addition, depending on the treatment, there is a problem that even the back surface of the endless belt may be treated, and the residue of the treatment liquid may bleed out over time.

  As described above, although the multilayer belt is highly functional, it has various problems in terms of the molding method and the characteristics of the completed belt as described above, so it is actually used in the market. This was rare, with single layer belts overwhelmingly more.

  Conventionally proposed endless belts with a multi-layer structure have increased material costs, take a long time to form, and therefore the cost of the endless belts is high, and the resulting endless belts have poor adhesion between layers. There were problems such as cracks in the belt, floating between layers, and peeling.

JP 2000-250328 A JP 2000-355432 A Japanese Patent Laid-Open No. 06-328628 JP-A-10-198189 Japanese Patent Laid-Open No. 3-130149 Japanese Patent Laid-Open No. 7-246671

  This invention makes it a subject to provide the endless belt which solved the said problem. More specifically, it is an object of the present invention to provide an endless belt that can be manufactured at low cost, improves the mutual adhesion of each layer, and has excellent durability without cracking or peeling even after long-term use.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research on the causes of cracks and peeling of multilayer belts and countermeasures thereof. As a result, the above-described problems can be solved by using an endless belt having the following configuration. The present inventors have found that an endless belt can be provided and have completed the present invention.

That is, the present invention is as follows.
(1) An endless belt for an electrophotographic apparatus comprising at least two layers having different constituent materials,
i) The constituent material of at least one layer is mainly composed of a thermoplastic resin,
ii) The endless belt for an electrophotographic apparatus is obtained by melt molding,
iii) An endless belt for an electrophotographic apparatus, wherein the adhesion strength between two adjacent layers exhibits 4 points or more as measured by the X cut tape method of JIS K 5400.
(2) The endless belt for an electrophotographic apparatus according to (1), wherein a halogen element is not contained in a molecular chain of the thermoplastic resin.
(3) The endless belt for an electrophotographic apparatus according to (1) or (2), wherein the layer containing the thermoplastic resin is a layer containing a crystalline thermoplastic resin.
(4) The electrophotographic apparatus according to (1) or (2), wherein the layer containing the thermoplastic resin is a layer containing an amorphous thermoplastic resin and a rubber component. Endless belt.
(5) The endless belt for an electrophotographic apparatus according to (4), wherein the content of the rubber component is 50% or less with respect to the total mass of the material constituting one layer.
(6) The endless belt for an electrophotographic apparatus according to any one of (1) to (5), wherein the elongation at break of the endless belt is 500% or less.
(7) The endless belt for an electrophotographic apparatus is obtained by melt molding using a coextrusion inflation molding method or a coextrusion molding method. (1) to (6) An endless belt for an electrophotographic apparatus according to any one of the above.
(8) The endless belt for an electrophotographic apparatus is obtained by melt-molding each layer after extrusion inflation molding or extrusion molding and stacking each layer, (1) to The endless belt for an electrophotographic apparatus according to any one of (6).
(9) The endless belt for an electrophotographic apparatus according to any one of (1) to (8), wherein the endless belt for an electrophotographic apparatus is used as an intermediate transfer belt.
(10) The endless belt for an electrophotographic apparatus according to any one of (1) to (8), wherein the endless belt for an electrophotographic apparatus is used as a transfer conveyance belt.
(11) A belt cartridge having the endless belt for an electrophotographic apparatus according to any one of (1) to (10).
(12) A process cartridge having the endless belt for an electrophotographic apparatus according to any one of (1) to (10).
(13) An image forming apparatus having the endless belt for an electrophotographic apparatus according to any one of (1) to (10), the belt cartridge according to (11), or the process cartridge according to (12).

  According to the present invention, it is possible to provide an endless belt for an electrophotographic apparatus having a multilayer structure which can be manufactured at low cost, improves the mutual adhesion of each layer, and has excellent durability without cracking or peeling even after long-term use. .

  Hereinafter, the present invention will be described in detail.

As described above, the endless belt for an electrophotographic apparatus of the present invention is an endless belt for an electrophotographic apparatus comprising at least two layers having different constituent materials,
i) The constituent material of at least one layer is mainly composed of a thermoplastic resin,
ii) The endless belt for an electrophotographic apparatus is obtained by melt molding,
iii) Further, the adhesion strength between two adjacent layers is characterized by showing 4 points or more as measured by the X cut tape method of JIS K 5400.

  In the present invention, a thermoplastic resin is used as a main component of the material of the layer constituting the endless belt, so that steps such as vulcanization and curing are not required as in a thermosetting material, and the manufacturing tact is shortened. There is an advantage that it can be manufactured at low cost. Further, a thermoplastic resin has a very high elastic modulus compared with thermosetting rubber and the like, and there are few problems of elongation and creep.

  In addition, since the thermoplastic resin is melt-molded, there is no need for steps such as solvent drying, vulcanization, and curing, and an endless belt can be obtained in a very simple process, and the adhesion between layers can be improved. . Furthermore, since a process such as using an adhesive is not required, an endless belt having a stable quality can be obtained at a low cost.

The endless belt for an electrophotographic apparatus of the present invention (hereinafter also simply referred to as an endless belt) is composed of at least two layers having different constituent materials, and at least one of the layers is
Contains a thermoplastic resin as a main component.

  Here, that the constituent materials of the layers are different means that the materials constituting the layers are not completely the same in terms of their types and contents. For example, even if the two layers contain the same thermoplastic resin as a main component, if one kind of additive is different, the material constituting the layer is different in the present invention. For example, even if the two layers contain the same thermoplastic resin as a main component, the materials constituting the layers are different in the present invention as long as the contents of the additives are different.

  Moreover, in this invention, it is preferable that not only one layer but two or more layers contain a thermoplastic resin as a main component. In particular, it is more preferable in terms of adhesion when adjacent layers contain the same kind of thermoplastic resin as a main component. However, for the purpose of separating the functions of the layers, the two layers may not necessarily use the same kind of thermoplastic resin, and may be different thermoplastic resins. At this time, in order to prevent the delamination, a compatible material such as an affinity material, a material having a close SP (solubility parameter) value, a material having a close melt viscosity, or the like is appropriately selected within the range satisfying the adhesiveness of the present invention. Good.

  When both are relatively compatible thermoplastic resins, there is no problem in adhesion, but depending on the characteristics and purpose of the endless belt of the electrophotographic apparatus, there may be a combination with insufficient compatibility. . In the case of a resin having poor compatibility, a third layer is provided between the two with a material having good compatibility with each resin, and adjustment can be made so as to obtain adhesion within the scope of the present invention.

  For example, a material having a high elastic modulus is required for the lower layer, and a high lubricity and non-adhesive material is used for the outermost layer in order to improve releasability from the toner. Due to the non-adhesiveness of the outermost layer, the adhesion with the lower layer material may not fall within the adhesion strength range defined in the present invention. In such a case, an intermediate layer using a material having an intermediate property between the lower layer material and the outermost layer material is provided between the lower layer and the outermost layer, thereby improving the adhesion between the two and within the scope of the present invention. You may make it become. Alternatively, when the surface layer material and the base layer material are different, each kneaded resin material may be used as an intermediate layer.

  Further, for example, in order to improve the adhesion between the A layer and the B layer, a third layer of a CD material blend of a C material having good compatibility with the A layer and a D material having good compatibility with the B layer is used as the third layer. Alternatively, it may be provided between the A layer and the B layer.

  There is no need to select a resin with excellent compatibility until sacrificing the target characteristics of the endless belt in the electrophotographic apparatus. First, it is first to satisfy the target characteristics as an endless belt. What is necessary is just to select a constituent material so that adhesiveness may be satisfied.

  In the present invention, a thermoplastic resin is contained as a main component of the material constituting the endless belt. However, in the present invention, the main component refers to one layer when the layers constituting the endless belt are determined for each layer. The case where it contains exceeding 50% with respect to the mass of the whole material to comprise. Of course, if the required characteristics as an endless belt of an electrophotographic apparatus are satisfied, the total amount can be made only of a thermoplastic resin.

  Next, the endless belt of the present invention is obtained by melt molding.

  Thus, by melt-molding a layer containing a thermoplastic resin as a main component, adjacent layers can be melted well and the adhesion between the layers can be improved.

  When melt molding is not performed, for example, in the case of adhesion, coating, and lamination by centrifugal molding, the other layer (B layer) 202 is simply carried on one adjacent layer (A layer) 201 as shown in FIG. In other words, the interface 200 is merely in the state of contact, and the adhesion between one layer (A layer) 201 and the other layer (B layer) 202 cannot be expected.

  In the present invention, the adjacent layers are not simply carried by one layer (A layer) 201 and the other layer (B layer) 202 by melt molding, but are adjacent to each other as shown in FIG. The mating layers are melted and diffused to each other, and the boundary 200 between the layers becomes unclear. As a result, the adhesion is improved by the anchoring effect between the layers, and the layers can be firmly bonded.

  By carrying out melt molding in this way, the adhesion can be improved by an order of magnitude compared to the case of using an adhesive or by coating, lamination by centrifugal molding, or the like.

  Therefore, in the present invention, the adhesion strength between two adjacent layers is also defined.

  The adhesion strength between two adjacent layers of the endless belt of the present invention is 4 points or more as measured by the JIS K 5400 X-cut tape method.

  This is because it has been found by the present inventors that the endurance belt does not have sufficient durability when the evaluation by the X-cut tape method of JIS K 5400 is less than 4 points. If it is 4 points or more, the adhesion as an endless belt is sufficient, and the endless belt is excellent in durability. From the viewpoint of obtaining a product more suitable for practical use, the adhesion strength is more preferably 6 points or more.

  In order to increase the adhesion strength between two adjacent layers to 4 points or more in this way, the thermoplastic resin layer is melt-molded as defined in the present invention to form a state in which the adjacent layers melt together. Can be achieved. However, if the value of the adhesion strength is not sufficient, the desired adhesion can be obtained by preparing a constituent material such as selecting a highly compatible material or a material having a close melt viscosity that is difficult to delaminate as described above. It is good to get strength.

  Various methods have been proposed for the adhesion test method. For example, there are a peel test method of JIS K 6854, a cross cut test method, and the like. However, according to the peel test method of JIS K 6854 and the like, in the case of a multi-layered endless belt as in the present invention, it is very difficult to prepare a sample, and it is impossible to determine the lack of local adhesion. In addition, for example, in the cross-cut test method, the influence at the time of sample preparation is likely to occur, and accurate determination is difficult. Furthermore, the preparation of the sample is complicated, and as a result, the inspection process takes time, which is not preferable. Therefore, the adhesion strength is preferably obtained by the X cut tape method of JIS K 5400. This method is a realistic method, and the troublesomeness of sample preparation is greatly reduced, and sample preparation can be performed easily. As a result, the man-hours required for the inspection process are shortened, and there is almost no influence during sample preparation. There is an advantage that the adhesiveness can be accurately determined, which is preferable.

  In addition, as a result of intensive studies on what the durability of the endless belt is caused by the thermoplastic resin, the present inventors have confirmed that there is a difference in the crystalline state of the thermoplastic resin. As a result, it was found that the crystalline resin is excellent in durability as it is.

  On the other hand, amorphous thermoplastic resins are often inferior in durability as they are, but it has also been found that adding a rubber component as a second component to this dramatically improves the durability.

That is, in the endless belt of the present invention, the layer containing the thermoplastic resin is a layer containing a crystalline thermoplastic resin, or a layer containing an amorphous thermoplastic resin and a rubber component. It is good.

Among the thermoplastic resins, the crystalline thermoplastic resin referred to in the present invention includes, for example, polyethylene (high density (HDPE), medium density (MDPE), low density (LDPE), linear low density (LLDPE), Ultra high molecular weight (UHMW-PE)), polyester resin (polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN)) polypropylene (PP), polyamide (PA), polyacetal (POM), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polymethylpentene (PMP), polytrimethylene terephthalate (PTT), polycyclohexylene dimethylene terephthalate (PCT) and the like can be exemplified.

  Moreover, the copolymer containing said resin, for example, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid ester copolymer, etc. may be sufficient.

  The crystalline thermoplastic resin described above is merely an example, and crystalline thermoplastic resins other than those listed here can also be used.

  Among the thermoplastic resins, the amorphous thermoplastic resin referred to in the present invention includes, for example, polystyrene (PS), acrylonitrile / styrene resin (AS), methacrylic resin (PMMA), polycarbonate (PC), polyphenylene ether. (PPE), polymethacrylstyrene (MS), polysulfone (PSF), polyethersulfone (PES), polyarylate (PAR), polyetherimide (PEI), polyamideimide (PAI), thermoplastic polyimide (PI), Polyetheretherketone (PEEK), cycloolefin polymer (COP), cycloolefin copolymer (COC), polyacrylonitrile (PAN), PET-G (polyethylene terephthalate (PET) and polycyclohexylenedimethylene terephthalate) PCT) and copolymers) and the like can be exemplified.

  Among the above amorphous resins, those obtained by adding and copolymerizing a rubber component include, for example, high impact polystyrene (HIPS), acrylonitrile / styrene / butadiene resin (ABS), methacryl / butadiene / styrene resin (MBS), and the like. It may be. Moreover, polyacrylonitrile (PAN) which is a copolymer of polyacrylonitrile, butadiene and acrylic acid may be used. Moreover, the copolymer containing said resin may be sufficient.

  The above-mentioned non-crystalline thermoplastic resin is merely an example, and non-crystalline thermoplastic resins other than those listed here can also be used.

  Rubber components used together with the amorphous thermoplastic resin of the present invention include natural rubber, styrene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, butyl rubber, chloroprene rubber, nitrile rubber, urethane rubber, Acrylic rubber, epichlorohydrin rubber, silicone rubber, fluorine rubber and the like can be mentioned.

  The range of the rubber component content may be determined according to the required properties as appropriate. When judged for each layer, even if 1% is added to the mass of the entire material constituting one layer, the effect is exhibited. If the effect is insufficient, the amount added may be increased. However, when the addition amount is too large, the durability is improved, but the creep resistance is lowered. A preferable addition amount is 50% by mass or less.

In the present invention, the rubber component includes all of an amorphous thermoplastic resin and a polymer blend, a polymer alloy, a copolymerized state, and a state where rubber particles are dispersed.

  Of course, the rubber component of the present invention may be used in combination with a crystalline resin as an additive.

  Further, the rubber component in the present invention includes a thermoplastic elastomer.

  In the present invention, in the case of a polymer alloy or a polymer blend of a crystalline thermoplastic resin and an amorphous thermoplastic resin, or a copolymer, if the proportion of the amorphous resin is larger, the amorphous resin, If the proportion of the crystalline resin is large, the crystalline resin is used.

  As described above, the endless belt of the present invention has a multi-layer structure, and at least one of the layers is preferably a crystalline thermoplastic resin or a mixture of an amorphous thermoplastic resin and a rubber component. As another layer, for example, a layer mainly composed of a thermoplastic elastomer may be provided. Examples of the thermoplastic elastomer of the present invention include urethane, ester, nitrile, styrene, polyolefin, and polyamide elastomers.

  In addition to a layer made of a crystalline thermoplastic resin or a mixture of an amorphous thermoplastic resin and a rubber component, even if a layer made of a thermoplastic elastomer having flexibility and a large elongation is provided, Due to the rigidity and creep resistance of the resin layer, sufficient mechanical strength can be maintained for the entire belt, so that elongation and creep do not occur.

  Moreover, it is preferable that the thermoplastic resin in this invention does not contain a halogen element in a molecular chain. For example, a fluororesin containing fluorine in the molecular chain has excellent functions such as releasability from toner due to its non-adhesiveness, but has poor adhesion to adjacent layers when it is made into a multilayer structure. There is a drawback. Moreover, the fluororesin material is generally very expensive and hinders cost reduction. In addition, there is a drawback that it is difficult to recycle.

  Moreover, polyvinyl chloride resin is mentioned as another halogen-containing thermoplastic resin. Certainly, the vinyl chloride resin has better adhesion than the fluororesin, and is a general-purpose resin with a large production volume and low price. However, it is preferable not to use it as a main component from the viewpoint of environmental suitability.

  However, if the main component is a thermoplastic resin containing no halogen element in the molecular chain, a thermoplastic resin containing a halogen element in the molecular chain or a substance containing a halogen element may be added as an additive substance. Also good.

  There is no restriction | limiting in particular about the molecular weight of the thermoplastic resin in this invention, What is necessary is just to adjust molecular weight etc. according to a shaping | molding method. For example, in the case of injection molding, the smaller the molecular weight, the better the moldability. In the case of extrusion, inflation, blow molding, etc., the higher the molecular weight, the better the moldability.

  The elongation at break of the endless belt is preferably 500% or less. In the case of exceeding 500%, it is not preferable that the endless belt is stretched with a certain tension in the electrophotographic apparatus because creep occurs.

Usually, a thermoplastic resin itself is an insulating material, and often alone does not function as an endless belt of an electrophotographic apparatus, and is used by adding a conductive agent or an antistatic agent in order to adjust electric resistance. For example, examples of the conductive filler include carbon black and various conductive metal oxides, and examples of the non-filler resistance adjuster include low molecular weight ionic conductive agents such as various metal salts and glycols, ether bonds, and the like. Examples thereof include an antistatic resin containing a hydroxyl group or the like in the molecule, or an organic polymer compound exhibiting electronic conductivity. Accordingly, the additive to be mixed for adjusting the electric resistance value of the electrophotographic endless belt of the present invention is not particularly limited.

  The amount of the conductive agent added is not particularly limited as long as it is less than 50% with respect to the total mass of the material constituting one layer when judged for each layer, but is preferably 0.1 to 40%. . When the addition amount is less than 0.1%, sufficient conductivity cannot be obtained, and when it exceeds 40%, the mechanical strength is lowered or the appearance is impaired.

  In the case of multiple layers, the addition amount of each layer may be appropriately selected in order to obtain desired characteristics. For example, the addition amount of the outermost layer may be minimized, or the addition amount of the lowermost layer may be minimized.

  In the endless belt of the present invention, various additives may be added according to the purpose.

  Examples of additives include various fillers (calcium carbonate, talc, mica, silica, alumina, aluminum hydroxide, magnesium hydroxide, barium sulfate, zinc oxide, zeolite, wollastonite, diatomaceous earth, glass beads, bentonite, Montmorillonite, asbestos, hollow glass beads, graphite, titanium oxide,), reinforcing fiber (glass fiber, carbon fiber, aluminum fiber, stainless steel fiber, brass fiber, metal powder, conductive metal oxide, organometallic compound, organometallic salt ), Filler, dispersant, neutralizer, plasticizer, flame retardant, crosslinking agent, foaming agent, lubricant (molybdenum disulfide), mold release agent, surface treatment agent, antioxidant, UV absorber, heat stability Agents, antifogging agents, pigments, dyes, fluidity modifiers, hydrolysis inhibitors, and the like.

  Of course, there may be a layer made of only a thermoplastic resin to which nothing is added.

  Based on the desired formulation, materials such as thermoplastic resins, conductive agents and additives may be premixed and then kneaded and dispersed with a twin-screw extruder or the like to form raw materials, or each material may be directly fed into the molding machine. Molding may be performed.

  The melt molding in the present invention can be specifically exemplified by known melt molding methods such as a co-extrusion molding method, a co-extrusion inflation molding method, a co-extrusion blow molding method, and an injection molding method. As long as the layer is formed through the melting step, the layer may be formed using a forming method other than those listed here.

  Among these, a preferable molding method includes a coextrusion inflation molding method or a coextrusion molding method. These methods are economically advantageous because multiple layers can be formed continuously at one time, and are also economically advantageous. Also, materials that are difficult to form by themselves, materials that have low elastic modulus, tend to stretch, creep, and are easy to tear. Molding can be performed by combining a material or the like with a material having good moldability. Further, in the case of three layers, there is an advantage that even a resin that is easily decomposed or a resin having adhesiveness can be molded by putting it in the intermediate layer, which is preferable because the range of choices of materials is widened.

  Further, each layer may be formed in advance as a single layer and then heat-sealed or melt-formed.

  That is, a method of extrusion molding or extrusion molding for each layer and stacking each layer and then melt molding is also preferable.

  Next, an example of a method for producing an endless belt for an electrophotographic apparatus used in the present invention will be described below.

  FIG. 3 shows an example of a schematic configuration of an endless belt forming apparatus (inflation apparatus) for an electrophotographic apparatus of the present invention. This molding apparatus is mainly composed of an extruder, an extrusion die, and a gas blowing device.

  First, materials such as a molding resin, a conductive agent, and additives are preliminarily mixed based on a desired formulation, and then the molding raw material kneaded and dispersed is put into a hopper 102 provided in the extruder 100.

  On the other hand, another layer of molding material is charged into a hopper 113 provided in the extruder 101.

  In the extruders 100 and 101, the set temperature and the screw configuration of the extruder are selected so that the forming raw material has a melt viscosity that enables belt forming in a later process, and the materials are uniformly dispersed.

  The forming raw materials are melted and kneaded in the extruders 100 and 101, respectively, to form a melt, and enter the two-layer annular die 103 at the same time. The annular die 103 is provided with a gas introduction path 104. When air is blown into the center of the annular die 103 from the gas introduction path 104, the melt passing through the annular die 103 is expanded in the radial direction in both layers simultaneously. The tubular film 110 is expanded and overlapped in two layers.

  The gas blown at this time can select nitrogen, carbon dioxide, argon, or the like in addition to air.

  The expanded molded body (tubular film) is pulled upward while being cooled by the external cooling ring 105. Usually, in the inflation device, a method is adopted in which the tube is crushed from the left and right by the stabilizing plate 106, folded into a sheet shape, pinched by the pinch roller 107 so that the internal air does not escape, and taken up at a constant speed.

  Next, the taken-up tubular film is cut with a cutting device 108 to obtain a tubular film composed of two layers having a desired size.

  In addition, the above description relates to a two-layer belt. However, when a single-layer extrusion molding is performed in advance and the layers are heat-sealed to form a multilayer structure, one extruder is used as shown in FIG. The kneaded melt of the extruder 100 can be sent to the annular die 103 for single layer and expanded to expand to obtain a single layer belt.

  Of course, when there are three or more layers, an extruder may be prepared according to the number of layers. As described above, in this method, it is possible to form not only a single layer but also a multi-layered electrophotographic endless belt in a single step and with high dimensional accuracy in a short time. The fact that this short time molding is possible means that mass production and low cost production are possible.

  Specifically, the creases generated by the co-extrusion inflation molding method can be removed, or each layer can be formed in advance as a single layer and then heat-sealed in layers. A method using a set of cylindrical shapes having different diameters is mentioned.

  The thermal expansion coefficient of the small-diameter cylindrical mold (inner mold) is set to be larger than that of the large-diameter cylindrical mold (outer mold), and the inner mold is covered with a cylindrical film formed on the inner mold. It is inserted into the outer mold, and the cylindrical film is sandwiched between the inner mold and the outer mold. The gap between the inner mold and the outer mold is obtained by calculating the difference between the heating temperature and the coefficient of thermal expansion between the inner mold and the outer mold and the required pressure.

  From the inside, the mold set in the order of the inner mold, the cylindrical film, and the outer mold is heated to near the softening point temperature of the resin used for the cylindrical film. Since the inner mold having a large coefficient of thermal expansion tends to expand beyond the inner diameter of the outer mold by heating, a uniform pressure is applied to the entire surface of the cylindrical film. At this time, the surface of the cylindrical film that has reached the vicinity of the softening point is pressed against the inner surface of the outer mold, and the folds can be removed. Thereafter, the cylindrical film can be obtained by cooling and removing the cylindrical film from the mold. According to this method, it is possible to adjust the dimensions and improve the surface properties at the same time.

  Moreover, a multilayer cylindrical film can be obtained by stacking films to be placed on the inner mold.

  The endless belt in the present invention may or may not have a joint. That is, it may be co-extruded into a sheet shape, and then the sheet is rolled and joined by ultrasonic welding or the like to form a cylindrical film.

The volume resistivity of the endless belt of the present invention is preferably in the range of 1 × 10 ⁵ Ω · cm to 1 × 10 ¹⁶ Ω · cm. The volume resistivity of each layer is preferably set so as to fall within the above range. Further, the magnitude of the resistance of each layer may be appropriately selected according to the target characteristics. When surface neutralization or the like is required, the resistance of the base layer is designed to be lower than the resistance of the lower layer, and when electrostatic adsorption is required, the surface layer resistance is increased and the lower layer resistance is decreased. If it is less than 1 × 10 ⁵ Ω · cm, the resistance is too low, and a sufficient transfer electric field cannot be obtained, and image omission and roughness may occur. If it exceeds 1 × 10 ¹⁶ Ω · cm, it is necessary to increase the transfer voltage, which tends to increase the size of the power source and the cost.

The thickness of the endless belt of the present invention is preferably 40 μm or more and 500 μm or less as a whole.
If it is less than 40 μm, the strength is insufficient, the film tends to be stretched, and the withstand voltage is also insufficient. If it exceeds 500 μm, flexible bending becomes difficult, the roller that stretches the belt cannot be followed, and accurate driving cannot be obtained.

  What is necessary is just to select the thickness of each layer suitably so that a desired characteristic may be acquired.

  The circumference of the endless belt of the present invention is in the range of 200 to 1000 mm. If it is less than 200 mm, the size of the paper is limited, and if it is 1000 mm or more, the size of the apparatus is increased, which is not preferable.

  The above-described volume resistivity, thickness, and circumference are merely examples, and the range is not particularly limited.

  When the endless belt of the present invention is actually mounted and used in an image forming apparatus, a member for preventing meandering or a position detecting member for detecting the position of the endless belt may be provided as necessary. .

  Hereinafter, an electrophotographic apparatus using the endless belt of the present invention as a transfer conveyance belt will be described in detail. FIG. 5 shows a schematic diagram of an example of an image forming apparatus using an endless belt as a transfer conveyance belt.

  The image forming apparatus shown in FIG. 5 forms toner images of different colors on a plurality of photoconductors as one type of color image forming apparatus using a color separation image superposition transfer system. A toner image on each photoconductor is transferred to obtain a full-color image by aligning the position with one transfer material conveyed in contact with each other.

The image forming apparatus shown in FIG. 5 has four image forming units I, II, III, and IV arranged in parallel in the upper part of the apparatus main body 320 as electrophotographic process means. , Photosensitive drums 301Y, 301M, 301C, 301BK as image carriers, primary charging rollers 302Y, 302M, 302C, 302BK as primary chargers, exposure units 303Y, 303M, 303C, 303BK, developing units 304Y, 304M, 304C, 304BK and cleaners 305Y, 305M, 305C, and 305BK are included. The developing devices 304Y, 304M, 304C, and 304BK contain yellow (Y), magenta (M), cyan (C), and black (BK) toners, respectively.

  A transfer device 310 is provided below the image forming units I to IV. The transfer device 310 is an endless transfer stretched between the drive roller 311, the driven roller 312 and the tension roller 313. The image forming apparatus includes a conveyance belt 314 and a transfer charger 315 disposed to face the photosensitive drums 301Y, 301M, 301C, and 301BK of the image forming units I to IV.

  On the other hand, at the bottom of the apparatus main body 320, a cassette 306 is provided which is formed by stacking and storing a plurality of recording papers P as a recording medium, and one recording paper P in the cassette 306 is fed by a paper feed roller 307. It is sent out one by one and conveyed to the registration roller 309 through the conveyance guide 308.

  A separation charger 316 and a fixing device 317 are disposed on the downstream side in the conveyance direction of the recording paper P in the apparatus main body 320, and a paper discharge tray 318 is attached outside the apparatus main body 320.

  In each of the image forming units I to IV, the photosensitive drums 301Y, 301M, 301C, and 301BK are rotationally driven at a predetermined speed in the direction of the arrow shown in the drawing, and these are uniform by the primary charging rollers 302Y, 302M, 302C, and 302BK, respectively. Is charged. When the exposure units 303Y, 303M, 303C, and 303BK perform exposure according to image information on the respective photosensitive drums 301Y, 301M, 301C, and 301BK that have been charged in this way, the photosensitive drums 301Y, 301M, 301C, and 301BK, An electrostatic latent image is formed on 301BK, and each electrostatic latent image is developed by each developer 304Y, 304M, 304C, 304BK, and is visualized as a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image, respectively. It becomes.

  On the other hand, the recording paper P conveyed from the cassette 306 to the registration roller 309 through the conveyance guide 308 as described above is sent out to the transfer device 310 at the timing by the registration roller 309 and is transferred to the transfer belt 314 of the transfer device 310. The recording paper P is adsorbed and moved together with the image forming units I to IV, and in the process, a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are applied to the recording paper P by the action of the transfer charger 315. Are transferred in layers.

  Then, the recording paper P that has received the transfer of each color toner image as described above is neutralized by the separation charger 316 and separated from the transfer belt 314, and then conveyed to the fixing device 317 to heat and fix the color toner image. Is finally discharged from the apparatus main body 320 and stacked on the discharge tray 318.

  In the above-described color image forming apparatus using the transfer conveyance belt, the example in which the recording paper P is fed in the horizontal direction has been shown.

The color image forming apparatus using the transfer / conveying belt has an advantage that a color image is formed in one process because the color images are superimposed and transferred while sequentially transferring the transfer paper to each recording apparatus, so that the image output time is fast. .

  An electrophotographic apparatus having an intermediate transfer belt using the electrophotographic endless belt of the present invention as an intermediate transfer belt will be specifically described.

  FIG. 6 shows a color image forming apparatus (copier or laser beam printer) using an electrophotographic process and using an endless belt as an intermediate transfer belt.

  Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter referred to as a photosensitive drum) that is repeatedly used as a first image bearing member, and is driven to rotate at a predetermined peripheral speed (process speed) in the direction of an arrow.

  The photosensitive drum 1 is uniformly charged to a predetermined polarity and potential by the primary charger 2 during the rotation process. Reference numeral 32 denotes a power source for the primary charger. Here, alternating current is superimposed on direct current, but only direct current may be applied. Next, exposure means (not shown) (color separation / imaging exposure optical system for color original images, scanning exposure system using a laser scanner that outputs a laser beam modulated in accordance with time-series electric digital pixel signals of image information, etc.) When the exposure light 3 is received, an electrostatic latent image corresponding to the first color component image (for example, a yellow color component image) of the target color image is formed.

  Next, the electrostatic latent image is developed with yellow toner Y as the first color by the first developing device (yellow color developing device 41). At this time, the developing devices of the second to fourth developing devices (magenta developing device 42, cyan developing device 43, and black developing device 44) are turned on and do not act on the photosensitive drum 1. The yellow toner image of the first color is not affected by the second to fourth developing devices.

  The intermediate transfer belt 5 is stretched around two rollers, a secondary transfer counter roller 8 and a tension roller 12, and is driven to rotate at the same peripheral speed as the photosensitive drum 1 in the direction of the arrow. The yellow toner image of the first color formed and supported on the photosensitive drum 1 is applied from the primary transfer roller 6 to the intermediate transfer belt 5 in the process of passing through the nip portion between the photosensitive drum 1 and the intermediate transfer belt 5. The primary transfer is sequentially performed on the outer peripheral surface of the intermediate transfer belt 5 by an electric field formed by the primary transfer bias.

  The surface of the photosensitive drum 1 after the transfer of the first color yellow toner image corresponding to the intermediate transfer belt 5 is cleaned by the cleaning device 13.

  Similarly, the second color magenta toner image, the third color cyan toner image, and the fourth color black toner image are sequentially superimposed and transferred onto the intermediate transfer belt 5, and a composite color corresponding to the target color image is obtained. A toner image is formed.

  Reference numeral 7 denotes a secondary transfer roller, which corresponds to the secondary transfer counter roller 8 and is supported in parallel so as to be separated from the lower surface of the intermediate transfer belt 5.

  A primary transfer bias for sequentially superimposing and transferring the first to fourth color toner images from the photosensitive drum 1 to the intermediate transfer belt 5 is applied from a bias power source 30 with a polarity (+) opposite to that of the toner. The applied voltage is, for example, in the range of +100 V to 2 kV.

  In the primary transfer process of the first to third color toner images from the photosensitive drum 1 to the intermediate transfer belt 5, the secondary transfer roller 7 can be separated from the intermediate transfer belt 5.

  The composite color toner image transferred onto the intermediate transfer belt 5 is transferred to the transfer material P, which is the second image carrier, with the secondary transfer roller 7 being in contact with the intermediate transfer belt 5 and the paper feed roller. 11, the transfer material P is fed at a predetermined timing to the contact nip between the intermediate transfer belt 5 and the secondary transfer roller 7 through the transfer material guide 10, and the secondary transfer bias is supplied from the power source 31 to the secondary transfer roller. 7 is applied. By this secondary transfer bias, the composite color toner image is secondarily transferred from the intermediate transfer belt 5 to the transfer material P as the second image carrier. The transfer material P that has received the transfer of the toner image is introduced into the fixing device 15 and fixed by heating.

  After the image transfer to the transfer material P is completed, a cleaning charging member 9 disposed so as to be detachable is brought into contact with the intermediate transfer belt 5, and a transfer material having a polarity opposite to that of the photosensitive drum 1 is applied. The transfer residual toner that is not transferred to P but remains on the intermediate transfer belt 5 is given a charge having a polarity opposite to that at the time of primary transfer. Reference numeral 33 denotes a bias power source. Here, alternating current is superimposed on direct current and applied. The transfer residual toner charged to a polarity opposite to that at the time of primary transfer is electrostatically transferred to the photosensitive drum 1 at and near the nip portion with the photosensitive drum 1, thereby cleaning the intermediate transfer member. Since this step can be performed simultaneously with the primary transfer, the throughput is not reduced.

  The electrophotographic endless belt of the present invention has been described mainly with respect to the case where the electrophotographic endless belt is used as a transfer conveyance belt or an intermediate transfer belt, but the electrophotographic endless belt of the present invention includes a photosensitive belt, a transfer belt, The present invention can be applied to all belts used in electrophotographic apparatuses such as a conveyance belt, a fixing belt, a developing belt, a charging belt, and a paper feeding belt.

  The endless belt of the present invention may be mounted on the electrophotographic apparatus main body as it is, or may be used as a belt cartridge that can be attached to and detached from the main body. The endless belt can also be used as a belt for a process cartridge in which an electrophotographic process member such as a latent image carrier or a charging member is integrated.

  The measuring method of various parameters in the present invention is as follows.

<Adhesion between adjacent layers>
Conforms to JIS K 5400 X-cut tape method.
In the case of three layers, the adhesion may be measured by the X-cut tape method from the front side and the back side. In the case of four or more layers, a sample may be prepared and measured by adjusting the amount of the cutter blade in the thickness direction according to the film thickness of each layer.

<Elongation at break>
Conforms to JIS K 7161, 7162.
Sample shape 20mm x 100mm strips Mark distance 50mm
Tensile speed 500mm / min

<Volume resistivity>
The measuring device uses an ultra-high resistance meter R8340A (manufactured by Advantest) for the resistance meter, and a sample box TR42 (manufactured by Advantest) for the sample box, but the main electrode has a diameter of 25 mm and the guard ring electrode has an inner diameter. The outer diameter is 41 mm.

The sample is created as follows. First, the electrophotographic belt is cut into a circle having a diameter of 56 mm with a punching machine or a sharp blade. One side of the cut-out circular piece is provided with an electrode on the entire surface by a Pt-Pd vapor deposition film, and the other side is provided with a main electrode having a diameter of 25 mm and an inner diameter of 38 m by a Pt-Pd vapor deposition film
m, and a guard electrode having an outer diameter of 50 mm is provided. Pt-Pd deposited film is mild sputter E1030
(Manufactured by Hitachi, Ltd.) is obtained by performing the vapor deposition operation for 2 minutes. The sample after the vapor deposition operation is used as a measurement sample.

  The measurement atmosphere is 23 ° C./55%, and the measurement sample is previously left in the same atmosphere for 12 hours or more. The measurement is performed with a discharge of 10 seconds, a charge of 30 seconds, and a major of 30 seconds, and the measurement is performed at an applied voltage of 100 V.

  Hereinafter, the present invention will be described in more detail with specific examples. In the examples, “part” means part by mass.

Example 1
<First layer resin formulation>
Polyacetal resin (POM) 80 parts Conductive carbon black 20 parts <Second layer resin formulation>
Polyacetal resin (POM) 70 parts Polyetheresteramide resin 10 parts Zinc oxide 20 parts

The polyacetal resin (POM) is a crystalline thermoplastic resin.
Using a twin screw extruder, each of the above blends was melt-kneaded separately at 190 ° C., extruded with a strand having a diameter of about 2 mm, and cut into pellets.

  Using the two-layer molding machine shown in FIG. 3, the above materials are put into hoppers of different extruders, and coextrusion inflation molding (molding temperature 190 ° C.) is performed with a two-layer annular die. A cylindrical film with the second layer on the outside was obtained.

  The cylindrical film 1 was subjected to size adjustment, surface smoothness adjustment, and crease removal using a pair of cylindrical bodies made of metals having different coefficients of thermal expansion. The cylindrical film 1 having a high thermal expansion coefficient (inner mold) was covered with the cylindrical film 1, and the cylindrical film 1 was inserted into a cylindrical body (outer mold) having a smooth inner surface and heated at 170 ° C. for 20 minutes. After cooling to room temperature, the tubular film was removed from the inner and outer molds to obtain a tubular film that had been adjusted in size, adjusted for surface smoothness, and had creases removed.

Both ends of this tubular film were further precisely cut to obtain an endless belt having a circumferential length of 600 mm and a width of 250 mm. The volume resistivity of this endless belt was 7 × 10 ¹¹ Ω · cm.

  As described above, an endless belt consisting of at least two layers was obtained, and when one of the belts was checked for adhesion by the X-cut tape method, it was 10 points and had sufficient adhesion. It was confirmed.

  The elongation at break of this belt was 70%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

(Example 2)
Pelletized with the same resin formulation as in Example 1. A single-layer cylindrical film was separately obtained from this material by extrusion inflation molding (molding temperature 190 ° C.) using the single-layer molding machine shown in FIG. The two layers are stacked so that the first layer is on the inside and the second layer is on the outside. Under the same conditions as in Example 1, a set of cylindrical bodies made of metals having different coefficients of thermal expansion is used. While performing the adjustment, the adjustment of the surface smoothness and the removal of the creases, the stacked layers were heat-sealed and molded. The cylindrical film 1 having a high thermal expansion coefficient (inner mold) was covered with the cylindrical film 1, and the cylindrical film 1 was inserted into a cylindrical body (outer mold) having a smooth inner surface and heated at 170 ° C. for 20 minutes. After cooling to room temperature, the tubular film was removed from the inner and outer molds to obtain a tubular film that had been adjusted in size, adjusted for surface smoothness, and had creases removed.

Both ends of this tubular film were further precisely cut to obtain an endless belt having a circumferential length of 600 mm and a width of 250 mm. The volume resistivity of this endless belt was 7 × 10 ¹¹ Ω · cm.

  As described above, an endless belt consisting of at least two layers was obtained, and when one of the belts was checked for adhesion by the X-cut tape method, it was 10 points and had sufficient adhesion. It was confirmed.

  The elongation at break of this belt was 70%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

(Example 3)
An endless belt composed of at least two layers was obtained in the same manner as in Example 1 except that the circumferential length was 440 mm. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient.

  The elongation at break of this belt was 70%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as an intermediate transfer belt and mounted on the electrophotographic apparatus shown in FIG. 6 to conduct a durability test on 50,000 full-color images. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

Example 4
<First layer resin formulation>
Polyacrylonitrile resin (PAN) 80 parts Conductive carbon black 20 parts <Second layer resin formulation>
Polyacrylonitrile resin (PAN) 95 parts Polyetheresteramide resin 5 parts

The polyacrylonitrile resin (PAN) is an amorphous thermoplastic resin and is a copolymer with at least polybutadiene (the ratio of polybutadiene is about 10% by weight).

An endless belt composed of at least two layers was obtained in the same manner as in Example 1 except that the blending was changed to the above blending, and the kneading temperature and the molding temperature were 220 ° C. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient. The volume resistivity of this endless belt was 1 × 10 ¹¹ Ω · cm.

  The elongation at break of this belt was 120%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

(Example 5)
The same material as that used in Example 4 was molded in the same manner as in Example 2 to obtain a single-layer cylindrical film. The obtained film was processed by the same melt molding method as in Example 2 to obtain an endless belt composed of at least two layers. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient.

  The elongation at break of this belt was 120%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

(Example 6)
Two different types of single-layer cylindrical films obtained in Example 5 were stacked so that the first layer was on the inside and the second layer was on the outside, and PFA having an outer diameter of Φ187 mm sealed at both ends It was put on the outer peripheral surface of the tube. Furthermore, a nickel electroformed sleeve having an inner diameter of Φ191 mm, a length of 320 mm, and a thickness of 0.5 mm is covered from above, and 0.4 (MPa) compressed air is sent from the inside of the PFA tube to inflate the PFA tube. The cylindrical film was sandwiched between PFA (inner peripheral surface) and a nickel electroformed sleeve (outer peripheral surface). In this state, the heat of the halogen heater was applied to the nickel electroformed sleeve, and the sleeve was heated to 170 ° C. Thereafter, the sleeve was cooled to room temperature, and the compressed air sent to the inside of the FPA tube was released to release the pinching. When the cylindrical film was taken out after the release, the crease disappeared.
In this way, an endless belt composed of at least two layers was obtained. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient.

  The elongation at break of this belt was 50%.

One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and mounted on the electrophotographic apparatus of FIG. 5, and a durability test of 50,000 full-color images was performed. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

(Example 7)
An endless belt consisting of at least two layers was obtained in the same manner as in Example 4 except that the circumference was 440 mm. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient.

  The elongation at break of this belt was 120%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as an intermediate transfer belt and mounted on the electrophotographic apparatus shown in FIG. 6 to conduct a durability test on 50,000 full-color images. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was again 10 points, and it was found that the belt had sufficient durability.

(Example 8)
<First layer resin formulation>
Polycyclohexylene dimethylene terephthalate resin (PCT) 80 parts Conductive carbon black 20 parts <Second layer resin formulation>
Urethane thermoplastic elastomer resin 95 parts Polyetheresteramide resin 5 parts

  The polycyclohexylene dimethylene terephthalate resin (PCT) is a crystalline thermoplastic resin.

  An endless belt composed of at least two layers was obtained in the same manner as in Example 1 except that the blending was changed to the above blending, and the kneading temperature and the molding temperature were 220 ° C. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient.

The elongation at break of this belt was 650%. The volume resistivity of the endless belt was 8 × 10 ¹¹ Ω · cm.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was still 10 points, but the elongation at break was large and some creep was generated, but it can sufficiently withstand use, It was found to have durability.

Example 9
<First layer resin formulation>
Polyacetal resin (POM) 80 parts Conductive carbon black 20 parts <Second layer resin formulation>
Polyamide resin (nylon 610) 95 parts Polyetheresteramide resin 5 parts

  Both the polyacetal resin and the polyamide resin are crystalline thermoplastic resins.

  An endless belt composed of at least two layers was obtained in the same manner as in Example 1 except that the blending was changed to the above blending, and the kneading temperature and the molding temperature were 220 ° C. When one of these was checked for adhesiveness by the X-cut tape method, it was 10 points, and it was confirmed that the adhesiveness was sufficient.

The elongation at break of this belt was 410%. The volume resistivity of this endless belt was 2 × 10 ¹² Ω · cm.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was 8 points. Probably because the adhesion between polyacetal and polyamide is slightly inferior. However, it was found to be a level that can withstand use and sufficient for durability.

(Example 10)
The first layer and the second layer were blended in the same manner as in Example 1. The third layer was natural polyacetal resin (POM), and a three-layer extruder (molding temperature 190 ° C.) was used. Was the inner side, the second layer was the middle, and the third layer was the outer side, and an endless belt consisting of at least two or more three layers was obtained in the same manner as in Example 1. When one of these was checked for adhesion by the X-cut tape method, it was 10 points between adjacent layers, and it was confirmed that the adhesion was sufficient.

The elongation at break of this belt was 70%. The volume resistivity of this endless belt was 3 × 10 ¹² Ω · cm.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was found that there were 10 points between adjacent layers, and the belt had sufficient durability.

(Example 11)
<First layer resin formulation>
Polyacrylonitrile resin (PAN) 80 parts Conductive carbon black 20 parts <Second layer resin formulation>
Polyacrylonitrile resin (PAN) 90 parts Conductive carbon black 10 parts <3rd layer resin formulation>
Polyacrylonitrile resin (PAN) 95 parts Polyetheresteramide resin 5 parts

  The above blends were melted and kneaded separately at 220 ° C. to obtain pellets.

As the fourth layer, natural polyacrylonitrile resin (PAN) is used, and a four-layer extrusion molding machine (molding temperature 220 ° C.) is used. The first layer is the innermost layer, followed by the second to fourth layers in order. An endless belt consisting of at least two or more four layers was obtained in the same manner as in Example 1 except that it was provided. When one of these was checked for adhesion by the X-cut tape method, it was 10 points between adjacent layers, and it was confirmed that the adhesion was sufficient.

The elongation at break of this belt was 120%. The volume resistivity of this endless belt was 8 × 10 ¹⁰ Ω · cm.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was found that there were 10 points between adjacent layers, and the belt had sufficient durability.

(Example 12)
<First layer resin formulation>
Polycarbonate resin (PC) 80 parts Polyether ester amide elastomer 20 parts <Second layer resin formulation>
Acrylonitrile, styrene, butadiene resin (ABS) 75 parts Conductive carbon black 5 parts Silicone resin particles 20 parts

  The polycarbonate resin (PC) is an amorphous thermoplastic resin, and the polyether ester amide elastomer is a rubber component.

  An endless belt composed of at least two layers was obtained in the same manner as in Example 1 except that the blending was changed to the above blending and the kneading temperature and the molding temperature were 250 ° C. When one of these was checked for adhesion by the X-cut tape method, it was 6 points. Since the non-adhesiveness of the silicone resin particles mixed for further improving the releasability with the toner is high, the adhesiveness seems to be slightly inferior. However, it is determined that the level is sufficient for use.

The elongation at break of this belt was 90%. The volume resistivity of this endless belt was 8 × 10 ¹² Ω · cm.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Visual observation revealed no lifting or peeling. When the adhesion of the belt after durability was confirmed by the X-cut tape method, it was 4 points. After all, since the non-adhesiveness of the silicone resin particles is high, the adhesion seems to be slightly inferior. However, it was found that it was still at a level that could withstand use and was sufficient for durability.

(Comparative Example 1)
<Adjustment of first layer compound>
Ethylene propylene diene terpolymer (EPDM) 100 parts by mass, zinc oxide 5 parts by mass, higher fatty acid 1 part by mass, conductive carbon black 10 parts by mass, paraffin oil 10 parts by mass, sulfur 2 parts by mass, vulcanization accelerator 1 part by mass of MBT, 1.5 parts by mass of vulcanization accelerator TMTD, and 1.5 parts by mass of vulcanization accelerator ZnMDC were mixed for 20 minutes while cooling with two rolls to prepare a compound.

<Adjustment of the second layer compound>
Ethylene propylene diene terpolymer (EPDM) 100 parts by mass, zinc oxide 5 parts by mass, higher fatty acid 1 part by mass, conductive carbon black 2 parts by mass, paraffin oil 10 parts by mass, sulfur 2 parts by mass, vulcanization accelerator 1 part by mass of MBT, 1.5 parts by mass of vulcanization accelerator TMTD, and 1.5 parts by mass of vulcanization accelerator ZnMDC were mixed for 20 minutes while cooling with two rolls to prepare a compound.

  The ethylene propylene diene terpolymer (EPDM) is a thermosetting rubber.

  Co-extrusion from a multi-layered annular die equipped with two conductive compound extruders (set temperature 170 ° C), vulcanization and polishing on an aluminum roller, and then pulling out the aluminum roller to obtain an endless belt made of rubber It was.

  As described above, an endless belt consisting of at least two layers was obtained, and when one of the belts was checked for adhesion by the X-cut tape method, it was 10 points and had sufficient adhesion. It was confirmed.

The elongation at break of this belt was 300%. The volume resistivity of this endless belt was 5 × 10 ¹⁰ Ω · cm.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and mounted on the electrophotographic apparatus of FIG. The color shift was bad from the beginning, but the print test was continued because it was within the allowable range. From the point where 30,000 sheets were printed, creep that was estimated to be due to belt elongation occurred, and the amount of color misregistration exceeded the allowable range. Although the adhesion was satisfactory, the endless belt as a whole was inferior in durability.

(Comparative Example 2)
A single-layer cylindrical film was obtained from the first-layer resin-blended pellets of Example 1 using the single-layer molding machine shown in FIG.

<Contains paint>
For second layer, 100 parts by mass of polyurethane elastomer, 40 parts by mass of conductive titanium oxide, 12 parts by mass of dispersion aid, 450 parts by mass of tetrafluoroethylene resin powder (particle size 0.3 μm), and 1200 parts by mass of DMF are mixed. The paint was adjusted.

  The paint obtained by the above blending was applied to the cylindrical film obtained by spray coating, and after drying the solvent, a belt consisting of two layers was obtained.

  As described above, an endless belt composed of at least two layers was obtained, and when one of the belts was checked for adhesion by the X-cut tape method, the score was 0, indicating that the adhesion was insufficient. confirmed.

  Adhesion was inadequate, but as a precaution, the endless belt obtained was mounted on the electrophotographic apparatus shown in FIG. 5 as a transfer conveyance belt other than the one used for confirmation of adhesion. Then, a continuous printing durability test of a full color image was conducted.

  The coating was peeled off from the beginning, and the durability was insufficient.

(Comparative Example 3)
Pelletized with the same resin formulation as in Example 1. Using this material, a single-layer cylindrical film was obtained separately using the single-layer molding machine shown in FIG.

  A belt consisting of three layers, in which a hot melt adhesive is applied to the entire outer peripheral surface of the first layer of cylindrical film, a second layer of cylindrical film is placed thereon, the adhesive is cured, and the adhesive layer is sandwiched therebetween. Got.

  As described above, an endless belt composed of at least two or more three layers was obtained, and when one of these belts was checked for adhesion by the X-cut tape method, there were 10 points between adjacent layers, and sufficient adhesion was obtained. It was confirmed that it has sex.

  However, distortion occurred due to curing shrinkage of the adhesive, and wrinkles were generated even when stretched on a roller, and these wrinkles appeared as an image, which was unusable for use.

(Comparative Example 4)
A single-layer cylindrical film was obtained from the first-layer resin-blended pellets of Example 1 using the single-layer molding machine shown in FIG.

  Since it is a single layer, delamination does not occur.

  The obtained endless belt was used as a transfer / conveying belt and mounted on the electrophotographic apparatus of FIG. As a result, a leak occurred in the agglomerated part due to poor dispersion of carbon black, and a hole was formed in the belt, which was not durable.

(Comparative Example 5)
<First layer resin formulation>
Polyacrylonitrile resin (PAN) 80 parts Conductive carbon black 20 parts <Second layer resin formulation>
Polyvinylidene fluoride resin (PVDF) 95 parts Polyetheresteramide resin 5 parts

  An endless belt composed of at least two layers was obtained in the same manner as in Example 1 except that the blending was changed to the above blending, and the kneading temperature and the molding temperature were 220 ° C. When one of them was checked for adhesion by the X-cut tape method, it was 2 points and the adhesion was insufficient.

  The elongation at break of this belt was 100%.

  One of the obtained endless belts, which was different from the one used for confirmation of adhesion, was used as a transfer conveyance belt and was mounted on the electrophotographic apparatus shown in FIG. Even with visual observation, floating and peeling were observed, and the durability was insufficient.

It is the figure which represented the state of the interface of the conventional multilayer belt typically. It is the figure which represented typically the state of the interface of the multilayer belt of this invention. It is a figure which shows an example of schematic structure of the shaping | molding apparatus of the endless belt (2 layers) of this invention. It is a figure which shows an example of schematic structure of the shaping | molding apparatus of the endless belt (single layer) of this invention. It is a figure which shows an example of schematic structure of the electrophotographic apparatus provided with the endless belt of this invention. It is a figure which shows an example of schematic structure of another electrophotographic apparatus provided with the endless belt of this invention.

Claims (13)

An endless belt for an electrophotographic apparatus comprising at least two layers having different constituent materials,
i) The constituent material of at least one layer is mainly composed of a thermoplastic resin,
ii) The endless belt for an electrophotographic apparatus is obtained by melt molding,
iii) An endless belt for an electrophotographic apparatus, wherein the adhesion strength between two adjacent layers exhibits 4 points or more as measured by the X cut tape method of JIS K 5400.   2. The endless belt for an electrophotographic apparatus according to claim 1, wherein a halogen element is not contained in a molecular chain of the thermoplastic resin.   The endless belt for an electrophotographic apparatus according to claim 1 or 2, wherein the layer containing the thermoplastic resin is a layer containing a crystalline thermoplastic resin.   The endless belt for an electrophotographic apparatus according to claim 1, wherein the layer containing the thermoplastic resin is a layer containing an amorphous thermoplastic resin and a rubber component.   5. The endless belt for an electrophotographic apparatus according to claim 4, wherein the content of the rubber component is 50% or less with respect to the mass of the whole material constituting one layer.   The endless belt for an electrophotographic apparatus according to any one of claims 1 to 5, wherein the elongation at break of the endless belt is 500% or less.   The endless belt for an electrophotographic apparatus is obtained by melt molding using a coextrusion inflation molding method or a coextrusion molding method, according to any one of claims 1 to 6, An endless belt for an electrophotographic apparatus according to the description.   The endless belt for an electrophotographic apparatus is obtained by extrusion inflation molding or extrusion molding for each layer, and melt molding after stacking the layers. An endless belt for an electrophotographic apparatus according to claim 1.   The endless belt for an electrophotographic apparatus according to any one of claims 1 to 8, wherein the endless belt for an electrophotographic apparatus is used as an intermediate transfer belt.   The endless belt for an electrophotographic apparatus according to any one of claims 1 to 8, wherein the endless belt for an electrophotographic apparatus is used as a transfer conveyance belt.   A belt cartridge having the endless belt for an electrophotographic apparatus according to any one of claims 1 to 10.   A process cartridge having the endless belt for an electrophotographic apparatus according to claim 1.   An image forming apparatus comprising the endless belt for an electrophotographic apparatus according to claim 1, the belt cartridge according to claim 11, or the process cartridge according to claim 12.

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