JP6930643B2 - Sheet-like member for image forming apparatus - Google Patents

Description

The present invention relates to a sheet-like member for a semi-conductive image forming apparatus such as a highly durable endless belt (endless belt) and a paper separating claw, which are excellent in roller habit resistance and crack resistance, and an extrusion molding method thereof.

Conventionally, as an image forming apparatus for OA equipment and the like, an electrophotographic method using a photoconductor and toner and an image forming apparatus using ink have been devised and put on the market. These devices are used for various conductive, semi-conductive, or insulating electrical resistances such as photoconductor belts, intermediate transfer belts, paper transfer transfer belts, transfer separation belts, charging tubes, developing sleeves, and fixing belts. Controlled, seamless (seamed belts) or seamless (seamless belts) endless belts are used.

For example, an intermediate transfer device used in an electrophotographic system is configured to once form a toner image on an intermediate transfer body and then transfer the toner to paper or the like. An endless belt made of a seamless belt is used for charging and eliminating static electricity on the toner on the surface layer of the intermediate transfer body. This endless belt is set to different surface electrical resistance and thickness direction electrical resistance (hereinafter referred to as "volume electrical resistance") for each model of machine, and is adjusted to be conductive, semi-conductive, or insulating.

In addition, the paper transfer transfer device temporarily holds the paper on the transfer transfer body, transfers the toner from the photoconductor onto the paper held on the transfer transfer body, and further separates the paper from the transfer transfer body by static elimination. It is configured. On the surface layer of the transfer transfer body, an endless belt with and without a seam is used for charging and eliminating static electricity on the paper. Like the intermediate transfer belt, this endless belt is set to have different surface electrical resistance and volume electrical resistance for each machine model.

Further, in the photoconductor, transfer, and fixing mechanism, in order to prevent the paper from being caught in the paper fixing roller, transfer belt, photoconductor drum, etc., a paper separation claw for separating the paper so as not to wind the paper is provided. A semi-conductive film-like member called is used.

By the way, in the case of a conductive endless belt used in an image forming apparatus such as an electrophotographic copying machine or a printer, it is sufficient because it is functionally driven by two or more rolls with high tension and high voltage for a long time. Mechanical durability is required.

In particular, in the case of an intermediate transfer belt used in an intermediate transfer device or the like, an image of toner is formed on the belt and transferred to paper. Therefore, if the belt loosens, stretches, or meanders during driving, the image High dimensional accuracy (small difference in circumference in the belt width direction and uniform thickness), high elastic modulus (high tensile modulus in the belt circumference direction), and high flexural resistance because it causes deviation. Those with excellent mechanical properties such as (hard to break) are desired.

Further, in recent years, electrophotographic image forming devices such as color laser printers and color LED printers have become more competitive with low-priced inkjet image forming devices. Therefore, the electrophotographic image forming apparatus is an image forming apparatus that prints at high speed by a tandem type paper transfer transfer in which four photoconductors are arranged and an intermediate transfer method, aiming at differentiation from the inkjet method by high-speed printing technology. Has been commercialized. Therefore, an endless belt for an image forming apparatus is required to have excellent durability such as further improvement in durability and wear resistance.

Furthermore, the demand for higher image quality is increasing, and in particular, high-quality images can be obtained in a wide range of temperature and humidity environments, and not only special paper for color printers, but also high-quality paper, recycled paper, and backing paper. It is necessary to obtain high image quality even on various types of paper such as paper and OHP film.

In addition, color printers and copiers, which have become smaller and smaller these days, have the transfer belt and the fixing heat source located close to each other. Therefore, the transfer belt is easily exposed to the high heat of the fixing heat source while being stretched on a roller. Therefore, it is necessary to improve the heat resistance of the endless belt material because the traces of the rollers remain on the surface of the transfer belt and easily cause an adverse effect on the image.

Further, among the endless belts used in the image forming apparatus, especially in the case of the transfer belt used in the intermediate transfer apparatus and the like, the demand for the endless belt for a high-quality image is high, and the toner on the photoconductor is subjected to electrostatic force. Transfer directly onto the transfer belt (primary transfer), synthesize a color image on the transfer belt, and then transfer the toner to paper by electrostatic force (secondary transfer), so the surface electrical resistance in the surface direction and the thickness direction of the transfer belt In addition to the importance of electrical resistance characteristics such as volume electrical resistance characteristics, there is an increasing demand for performance improvement in all of surface physical characteristics, surface chemical characteristics, and abrasion resistance.

On the other hand, with regard to the paper separation claws, not only special paper for color printers but also high-quality paper and rough paper with large irregularities are becoming more and more important in terms of abrasion resistance and abrasion resistance.

In response to the demand for abrasion resistance of sheet-like members such as endless belts for image forming devices and paper separation claws, various proposals have been made to use polyetheretherketone (PEEK) resin as a constituent material of these members.

For example, Patent Document 1 describes a seamless semi-conductive belt having a ^{volumetric electrical resistance value in the range of 10 8} to 10 ¹⁷ Ω cm, which is formed by extruding a material containing PEEK resin containing a conductive filler as a main component into a tube shape. Is disclosed.

Patent Document 2 describes a single-layer intermediate transfer belt made by extruding PEEK resin, in which the crystallinity of the resin on the outer peripheral surface is higher than that on the inner peripheral surface and the hardness on the inner side is lower than that on the outer side. Specifically, the crystallinity of the outer peripheral surface is 18% or more, the crystallinity of the inner peripheral surface is 12% or less, the hardness of the outer peripheral surface is 0.25 GPa or more, and the hardness of the inner peripheral surface is 0. An intermediate transfer belt of 20 GPa or less is disclosed.

Patent Document 3 discloses a seamless semi-conductive belt containing 19 to 30% by mass of acetylene black with respect to a thermoplastic resin and having a volume resistivity in ^{the range of 1 × 10 9} to 1 × 10 ^{12 Ωcm.} It is described that the plastic resin is PEEK resin.

Patent Document 4 contains 100 parts by weight of PEEK and 5 to 25 parts by weight of a conductive filler, and has an average thickness of 30 to 250 μm according to a MIT type tester specified in JIS P-8115. A semi-conductive film having a reciprocating bending count of 5000 times or more measured by a bending strength test method is disclosed.

Japanese Unexamined Patent Publication No. 6-254941 Japanese Unexamined Patent Publication No. 2009-63902 Japanese Unexamined Patent Publication No. 2012-133220 Japanese Unexamined Patent Publication No. 2005-112942

The semi-conducting belt of Patent Document 1 is obtained by blending a conductive filler with PEEK resin (14% by weight of acetylene black is blended in the example) and simply extruding from an annular die to control the cooling temperature of the sizing portion. Since the temperature is set to 0 to 90 ° C., preferably 20 to 60 ° C., crystallization of the PEEK resin is unlikely to occur during film formation. Therefore, when the obtained belt is left in a state of being stretched on a roller at a high temperature of 60 ° C., habit marks due to the roller are likely to occur, and therefore, there is a problem that an image abnormality is likely to occur.

In the intermediate transfer belt of Patent Document 2, in order to increase the crystallinity of the outer peripheral surface, the outer peripheral surface is heated by an external heating device, the hardness of the outer peripheral surface is high, and the scratch resistance is improved, but the surface crystallization progresses. There is a problem that the rigidity is increased and the crack resistance is lowered.

In Patent Document 3, 19 to 30% by mass of acetylene black is blended in PEEK resin, and there is a problem that crack resistance is poor because the blending amount of acetylene black is too large.

In the semi-conducting film of Patent Document 4, in order to improve crack resistance, the melted film extruded from the annular die is preferably rapidly cooled to 80 to 90 ° C. (85 ° C. in the examples) to form a film. Crystallization is reduced. Therefore, as in Patent Document 1 described above, when the belt obtained from the annular die is left stretched on the roller at a high temperature of 60 ° C., habit marks due to the roller are likely to occur. There is a problem that tends to cause image abnormalities. Furthermore, by reducing the lip clearance, it is said that the deformation of the film in the molten state is reduced and the unevenness of the thickness and volume resistivity is reduced. In the embodiment, the film is extruded while being sheared with a small clearance of 0.5 mm. Therefore, when extruding at a high speed, there is also a problem that an appearance roughness called a melt fracture is likely to occur.

As described above, although PEEK resin has been conventionally proposed as a sheet-like member such as an endless belt for an image forming apparatus and a paper separating claw, both have crack resistance (breaking resistance) and heat resistance. None of them were satisfied with (roller resistance).
This is because conventional endless belts, which are made of PEEK resin mixed with a conductive filler such as carbon black, are not sufficiently crystallized and have a roller habit because they are rapidly cooled during melt extrusion molding because mechanical durability is emphasized. Because it is easy to make marks.
That is, in the prior art, a PEEK resin having high rigidity and excellent heat resistance and a high crystallization peak temperature is used, and the crack resistance is improved by quenching when the film is formed by melt extrusion molding. With such a conventional method, the crack resistance cannot be sufficiently increased, and the endless belt having excellent roller habit resistance and crack resistance cannot be obtained.

Specifically, among the above-mentioned Patent Documents 1 to 4, the sheet-like member obtained by press-molding the PEEK resin described in Patent Documents 2 to 4 having the product name of PEEK resin at 400 ° C. _{The temperature-decreasing crystallization peak temperature T c} obtained by measuring by the DSC measurement specified in the present invention is as follows, and all have a high temperature-decreasing crystallization peak temperature T _c of 300.0 ° C. or higher. There is no technical idea of using a material having a low temperature-decreasing crystallization peak temperature T _c.
PEEK "450G" manufactured by _{Victrex: T c} = 300.5 ° C
PEEK "381G" manufactured by Victrex: T _c = 301.1 ° C
PEEK "151G" manufactured by Victrex: T _c = 304.7 ° C
Victrex PEEK "90G": T _c = 307.2 ° C

As described above, in the conventional PEEK belt, it is difficult to achieve both crack resistance and roller habit resistance, and further, the characteristics required for the image forming apparatus such as wear resistance and semiconductivity are fully satisfied. In addition, the actual situation is that endless belts for image forming devices, which are also excellent in productivity, have not been provided.

The present invention solves the above problems, and an object of the present invention is to provide a highly durable sheet-like member for an image forming apparatus, which has excellent roller habit resistance, crack resistance, and desired semiconductivity. It is in.

In the process of diligently studying to solve the above problems, the present inventors pay attention to the crystallization peak temperature at the time of cooling the PEEK resin, and it is better to highly crystallize the material having a large high molecular weight component. It was presumed that crack resistance and roller habit resistance could be achieved at the same time as compared to a material in which a material having a small amount of components was low-crystallized.
That is, if the crystallization peak temperature is low, the heat resistance is lowered, but it is difficult to crystallize because it hinders the molecular motion during cooling from the time of melting, and it can be presumed that the material has a large amount of high molecular weight components. I thought it might work in my favor.
On the other hand, if the crystallization peak temperature is high, the low molecular weight component of PEEK resin tends to become crystal nuclei and the crystallinity tends to increase, and the heat resistance is high, but the rigidity in the micro region is also high and the crack resistance is lowered. I thought I might do it.
Based on this idea, contrary to the conventional method of using a material with a high crystallization peak temperature, that is, PEEK resin having high rigidity and heat resistance, and quenching in the film forming process to improve crack resistance, It is better to select a material with a low crystallization peak temperature, that is, PEEK resin with excellent crack resistance, cool it in the film forming process, and then crystallize it to improve the roller habit resistance. We have found that the roller habit can be compatible with each other advantageously, and have reached the present invention.

The present invention has been achieved based on such findings, and the gist of the present invention is as follows.

[1] A sheet-like member used in an image forming apparatus, which contains a polyetheretherketone resin and a conductive filler of less than 19% by weight, and has a temperature-decreasing crystallization peak temperature T measured by the following differential scanning calorimetry. _A sheet-like member for an image forming apparatus, wherein c is less than 299.0 ° C.
<Measurement of differential scanning calorimetry>
_{The temperature-decreasing crystallization peak temperature T c} in the process of raising the temperature of the sheet-shaped member to 400 ° C. at a heating rate of 10 ° C./min and then cooling it to 23 ° C. at 10 ° C./min is measured.

[2] In [1], the number of folds at R = 0.38 mm is 5000 or more and less than 20,000, and the number of folds at R = 2 mm is measured by the following measurement of the number of folds. A sheet-like member for an image forming apparatus, characterized in that it is 500,000 times or more.
<Measurement of folding resistance>
In accordance with JIS P-8115 (2001), a test piece having a width of 15 mm and a length of 100 mm is cut from a sheet-shaped member, and the test piece is bent at a bending speed of 175 times / minute by a MIT tester. Using a bending jig with a radius of curvature R = 0.38 mm and 2 mm at the tip of the tip under the conditions of a rotation angle of 135 ° to the left and right and a tensile load of 1.0 kgf, the number of bends leading to each breakage is measured. The average value of the measured values at three points is defined as the number of folding resistances.

[3] The sheet-like member for an image forming apparatus according to [1] or [2], wherein the roller habit restoration rate determined by the following measurement of the roller habit restoration rate is 70% or more.
<Measurement of roller habit restoration rate>
A sheet-like member whose condition was adjusted for 24 hours or more under the conditions of a temperature of 23 ° C. and a humidity of 50% was cut into a 15 mm width and a 44 mm length, and this test piece was cut into a roller having a diameter of 14 mm, and the test piece length direction was the circumferential direction of the roller. After leaving it in a constant temperature and humidity layer with a temperature of 60 ° C and a humidity of 95% for 2 hours and then leaving it in an environment with a temperature of 23 ° C and a humidity of 50% for 24 hours, the test piece was released from the roller and the temperature was changed. When left at 23 ° C. and 50% humidity for 2 hours, the roller habit restoration rate (%) is calculated from the width L of the opening of the test piece that has been habituated into a substantially C-shaped cross section by a roller by the following formula.
Roller habit restoration rate (%) = {opening width L (mm) / test piece length 44 (mm)} x 100

[4] In any one of [1] to [3], a sheet-like member for an image forming apparatus, which is an endless belt or a paper separating claw.

[5] A resin composition containing a polyetheretherketone resin and a conductive filler is melt-extruded into a tube shape via an annular die, and the inner surface of the tube-shaped extruded product is brought into contact with a cooling mandrel to be cooled and solidified. A method for continuously melt-extruding a sheet-shaped member for an image forming apparatus by a cooling mandrel method is characterized in that a frost line of the extruded product is formed between a molten resin outlet portion of the annular die and the cooling mandrel. A method for extruding a sheet-like member for an image forming apparatus.

According to the present invention, it is possible to provide a highly durable sheet-like member for an image forming apparatus having excellent roller habit resistance, crack resistance, and desired semiconductivity.

It shows an example of embodiment of the extrusion molding method of the sheet-like member for an image forming apparatus of this invention, and is the schematic cross-sectional view which shows the melt extrusion molding process.

Embodiments of the present invention will be described in detail below.
In the present invention, the "main component" refers to a material containing a plurality of components, which is the most contained in the compounded material. Further, "sheet-like member" is used in a broad sense including "film-like member".

[Sheet-like member for image forming apparatus]
The sheet-like member for an image forming apparatus of the present invention contains a polyetheretherketone resin and a conductive filler of less than 19% by weight, and has a temperature-decreasing crystallization peak temperature T _{c measured by the following differential scanning calorimetry (DSC) measurement.} (Hereinafter, it may be simply referred to as "lower temperature crystallization peak temperature T _c ".) It is characterized in that it is less than 299.0 ° C.
<Measurement of differential scanning calorimetry>
_{The temperature-decreasing crystallization peak temperature T c} in the process of raising the temperature of the sheet-shaped member to 400 ° C. at a heating rate of 10 ° C./min and then cooling it to 23 ° C. at 10 ° C./min is measured.

If the temperature-decreasing crystallization peak temperature T _c is low, the heat resistance is low, but there are many high molecular weight components, which is considered to be advantageous for crack resistance.
It is also considered that the higher the temperature-decreasing crystallization peak temperature T _c , the higher the crystallinity tends to be due to the low molecular weight components becoming crystal nuclei, the higher the heat resistance, the higher the rigidity in the micro region, and the higher the crack resistance. Decreases.
In the present invention, contrary to the conventional method of improving crack resistance by using a material having a high temperature-decreasing crystallization peak temperature _Tc , that is, PEEK resin having high rigidity and heat resistance and quenching under film-forming conditions, the temperature is lowered. A PEEK resin with a low crystallization peak temperature _Tc , that is, a PEEK resin with excellent crack resistance, is selected, cooled under film-forming conditions and then crystallized to improve the roller habit resistance, thereby improving the crack resistance. Achieves both property and roller resistance.

<Low temperature crystallization peak temperature T _c >
The sheet-like member for an image forming apparatus of the present invention is characterized in that the temperature-decreasing crystallization peak temperature T _c is less than 299.0 ° C.

The low temperature-decreasing crystallization peak temperature T _c means that the resin can have a low crystallization rate and a large molecular weight. By supplementing the crack resistance with the high molecular weight and adopting a film-forming method by cooling. The roller habit resistance can be improved, and both crack resistance and roller habit resistance can be achieved at the same time.

_{The preferred temperature-decreasing crystallization peak temperature T c} of the sheet-shaped member for an image forming apparatus of the present invention is 297.5 ° C. or lower, particularly preferably 297.0 ° C. or lower. However, a material having an excessively low temperature-decreasing crystallization peak temperature T _c is not preferable in terms of heat resistance (roller resistance), and the temperature-decreasing crystallization peak temperature T _c of PEEK resin is usually 292.0 ° C. or higher. _{Therefore, the temperature-decreasing crystallization peak temperature T c} of the sheet-like member for an image forming apparatus of the present invention is preferably 292.0 ° C. or higher, more preferably 292.5 ° C. or higher, and particularly 293.0 ° C. or higher. Is preferable.

<PEEK resin>
In order to realize the above-mentioned temperature-decreasing crystallization peak temperature T _c , the PEEK resin used in the present invention itself has a temperature-decreasing crystallization peak temperature T _c of less than 30.0 ° C., particularly 298.0 ° C. or less, particularly. It is preferably 297.5 ° C. or lower and 292.0 ° C. or higher.
The temperature-decreasing crystallization peak temperature T _c of the PEEK resin used in the present invention for realizing the temperature-decreasing crystallization peak temperature T _c of the sheet-shaped member for an image forming apparatus of the present invention is the sheet-shaped member for an image forming apparatus of the present invention. The reason why it does not always match the temperature-decreasing crystallization peak temperature T _{c is as follows.}
That is, the sheet-like member is blended with a conductive filler such as carbon black, and is formed into a film through steps such as heat kneading and melt extrusion. At this time, the conductive filler itself such as carbon black acts as a nucleating agent for crystallization (easy to crystallize), and the PEEK resin is crosslinked (increased in molecular weight) or deteriorated (molecular weight becomes large) by heat kneading and melt extrusion. The temperature-decreasing crystallization peak temperature _Tc of the obtained sheet-like member varies depending on the compounding components, the film-forming method, the manufacturing conditions, etc., and is not necessarily the temperature-decreasing crystallization peak temperature of the PEEK resin used as the raw material. Not the same as T _c.

The sheet-like member for an image forming apparatus of the present invention contains 70% by weight or more of PEEK resin as a main component in order to effectively exert the effects of wear resistance, crack resistance, and roller habit resistance by using PEEK resin. In particular, it is preferably contained in an amount of 80% by weight or more.

<Thermoplastic resin>
In the sheet-like member for an image forming apparatus of the present invention, a thermoplastic resin having heat resistance as an alloy material may be blended with the PEEK resin as the main component as long as the object of the present invention is not impaired.

The thermoplastic resin may be a thermoplastic crystalline resin or a thermoplastic amorphous resin, and may be polyamide (PA), polyamideimide (PAI), polyimide (PI), polyacetal (POM), or polyarylate. (Par), Polycarbonate (PC), Polyalkylene terephthalate (PAT), Polyethylene terephthalate (PET), Polybutylene terephthalate (PBT), Polyethylene naphthalate (PEN), Polybutylene naphthalate (PBN), Polytrimethylene terephthalate (PTT) ), Polymethylmethacrylate (PMMA), Polyphenylene oxide (PPE), Polyethersulfone (PES), Polymethylpentene (PMP), Polyoxybenzylene (POB), Liquid polyester, Polysulfone (PSF), Polyphenylene sulfide (PPS), Polyphenyl sulfone (PPSU), Polybisamide triazole, Polyaminobismaleimide, Polyetherimide (PEI), Acrylic, Polyfluorinated vinylidene (PVDF), Ethylenetetrafluoroethylene copolymer (ETFE), Hexafluoropropylene , Perfluoroalkyl vinyl ether copolymer, acrylate alkyl ester copolymer, polyester ester copolymer, polyether ester copolymer, polyethylene amide copolymer, polyurethane copolymer and the like, and these are one kind. May be used alone, or two or more kinds may be used as a mixture.

Of these, PAI, PI, PES, PPSU, PEI, and PPS are preferable because they have heat resistance that can withstand alloying with PEEK resin, and among them, PES, PPSU, and PEI are particularly preferable.

<Conductive filler>
The conductive filler used in the present invention is not particularly limited as long as it satisfies the performance required for the application, and various types can be used. Specifically, carbon black, carbon fiber, graphite, and the like can be used. Conductive metal-based fillers such as carbon-based fillers, metal-based conductive fillers, and metal oxide-based conductive fillers can be used. One of these may be used alone, or two or more thereof may be used as a mixture.

In selecting the conductive filler in the present invention, it is necessary to consider the mechanical properties, electrical properties, dimensional properties, and chemical properties of the obtained sheet-like member, and from this point of view, the conductive filler is a carbon black powder product. Or, those containing a granular product as a main component are preferable. In this case, carbon black may be used as a main component, and a non-conductive filler-based material such as an antistatic agent described later may be used in combination as a sub-component, or a composite with a conductive metal-based filler may be used. However, since it is preferable that the surface energy is high, it is preferable to use only carbon black as the conductive component.

When a conductive filler such as carbon black is blended, surface irregularities are formed on the sheet-like member, but it may be preferable to have appropriate irregularities in terms of blocking resistance.

The blending amount of the conductive filler varies depending on the type of the conductive filler used, but the content in the sheet-like member for the image forming apparatus of the present invention is in the range of 19% by weight or less, depending on the desired degree of semiconductivity. It is preferable to make appropriate adjustments. If the content of the conductive filler exceeds 19% by weight, the crack resistance is lowered, which is not preferable. If the content of the conductive filler is too small, the conductivity will not be exhibited, the dispersed state of the conductive filler will be rough, the electrical resistivity will be liable to vary, and the contact resistance will be greatly affected by the environment. For example, when mounted on an image forming apparatus as an endless belt, an image abnormality may occur depending on the environment. Therefore, the content of the conductive filler in the sheet-shaped member is preferably 10% by weight or more, particularly preferably 12 to 18% by weight.

As the type of carbon black preferably used as a conductive filler, acetylene black, furnace black, channel black and the like can be preferably used, and among them, impurities called ash such as potassium, calcium and sodium are few and cause poor appearance. Acetylene black, which is difficult to use, can be particularly preferably used, and its average primary particle size is preferably about 25 to 45 nm. Further, carbon black coated with a resin, carbon black subjected to known post-treatment such as heat-treated carbon black or graphitized carbon black can be used as long as the object of the present invention is not impaired.

Further, carbon black treated with a coupling agent such as a silane-based, an aluminate-based, a titanate-based, or a zirconate-based coupling agent may be used for the purpose of improving dispersibility and suppressing gas generation.

Examples of conductive fillers other than carbon black include powders such as silver, nickel, copper, zinc, aluminum, stainless steel, and iron, and so-called aluminum-doped zinc oxide, antimon-doped tin oxide, phosphorus-doped tin oxide, and tin-doped indium oxide. Granular, fibrous, and flaky conductive metal oxide fillers are preferably used.

Among these conductive fillers other than carbon black, so-called conductive metal oxide fillers such as aluminum-doped zinc oxide, antimon-doped tin oxide, phosphorus-doped tin oxide, and tin-doped indium oxide, which are granular, are preferable, and the average particle size is Those having a thickness of 5 μm or less are preferable because the surface smoothness of the sheet-like member to be formed can be maintained.

<Additional compounding material; optional ingredient>
Any compounding component can be blended in the sheet-shaped member for an image forming apparatus of the present invention according to various purposes.

Specifically, antioxidants, heat stabilizers, various plasticizers, light stabilizers, UV absorbers, neutralizers, lubricants, antifogging agents, anti-blocking agents, slip agents, cross-linking agents, cross-linking aids, coloring. Various additives such as agents, flame retardants, dispersants, and waxes can be added.
Further, as a conductive component other than the conductive filler, a polymer polymer type antistatic agent such as a polyether ester amide or an ionic conductive substance such as a quaternary ammonium salt may be used in combination.

Further, as the constituent material of the sheet-like member for the image forming apparatus, various elastomers and thermosetting resins are used as the third and fourth components in addition to the above-mentioned various thermoplastic resins as long as the effects of the present invention are not significantly impaired. , A compounding material such as a filler other than the conductive filler can be blended.

[Manufacturing method of sheet-shaped member for image forming apparatus]
The method for manufacturing the sheet-shaped member for an image forming apparatus of the present invention will be described below.
The method for producing the sheet-shaped member of the present invention is not particularly limited, and it can be produced according to a conventional method. However, a resin composition containing PEEK resin and a conductive filler is formed into a tube shape via an annular die. A molten resin outlet of an annular die in an extrusion molding process in which a sheet-like member for an image forming apparatus is continuously melt-extruded by an internal cooling mandrel method in which the inner surface of the tubular extruded product is brought into contact with a cooling mandrel to be cooled and solidified. _{The temperature-decreasing crystallization peak temperature T c} , which is excellent in crack resistance, can be produced by the extrusion molding method of the sheet-like member for an image forming apparatus of the present invention in which a frost line of an extruded product is formed between a portion and a cooling mandrel. It is preferable to use a low PEEK resin and improve the roller habit resistance by post-crystallization by slow cooling to more reliably achieve both crack resistance and roller habit resistance.

<Heat kneading of molding material>
Prior to molding, first, PEEK resin, conductive filler and the like are heat-kneaded. The heat kneading means is not particularly limited, and a known technique can be used. For example, if PEEK resin, a conductive filler, and other additive components to be blended as needed are heat-kneaded to obtain a resin composition, a uniaxial extruder, a twin-screw kneading extruder, a Banbury mixer, a roll, etc. Brabender, plastic, kneader, etc. can be used. In particular, a method in which these are mixed by a twin-screw kneading extruder, pelletized, and then molded is preferably used.

When the produced pellets are subjected to melt extrusion molding, the fluidity of the pellets can be improved by impregnating the pellet surface with a lubricant such as calcium stearate by a method such as dry blending in order to obtain extrusion stability. desirable. In this case, the amount of the lubricant to be attached is preferably 0.01 or more and 0.5 parts by weight, and more preferably 0.02 or more and 0.3 parts by weight with respect to 100 parts by weight of the pellet.

<Molding method>
In the present invention, the molding method is not particularly limited, and a known method such as a continuous melt extrusion molding method, an injection molding method, a blow molding method, or an inflation molding method, a centrifugal molding method, or a rubber extrusion molding method is adopted. However, a particularly preferable method is a continuous melt extrusion molding method. In particular, an extrusion molding method in which an extruded product (melted tube) extruded into a tube from an annular die is taken out while being cooled or cooled and solidified is preferable, and in particular, an internal cooling mandrel method of a downward extrusion method capable of controlling the inner diameter of the tube with high accuracy. Alternatively, a vacuum sizing method is preferable. In particular, the internal cooling mandrel method is the most preferable as a method for forming a belt for an image forming apparatus because a seamless belt can be easily obtained. In this case, it is preferable that the annular die is provided with a plurality of temperature control mechanisms in the circumferential direction thereof. Further, the cooling of the molten tube is preferably performed by bringing a mold whose temperature is adjusted in the range of 80 to 150 ° C. into contact with the inside or the outside thereof, and in this way, the molten tube is taken up while maintaining the cylindrical shape. Is preferable.

Further, after a film having creases is once produced by an inflation molding method, it may be used as an endless belt-shaped sheet-like member with the creases disappeared by post-processing, and the strip-shaped sheet is processed once and then connected. It may be a sheet-like member with a seam.

As a molding method, the extrusion molding method is advantageous in terms of cost, but it is generally difficult to produce a sheet-like member having a good dependence of the electric resistance value on the applied voltage. However, it is preferable because the dependence of the electric resistance value on the applied voltage can be reduced by selecting the type of PEEK resin or conductive filler to be used or setting the following molding conditions.

In particular, (a) the take-up speed at which the molten tube during extrusion molding is continuously taken up after being cooled is taken at a medium speed of 0.5 m / min or more and 2 m / min, thereby conducting conductivity over the entire thickness direction. The filler is highly oriented, or (b) the thickness of the sheet-like member is set to 0.12 or less with respect to the lip clearance of the die mold, and the molding material in which the conductive filler is dispersed is extremely lowly oriented. If the sheet-like member is extruded with, or (c) the sheet-like member is made into a thin film of 120 μm or less to reduce the orientation difference between the surface layer and the center, the sheet-like member has a small dependence on the applied voltage of the electric resistance value. Can be easily and inexpensively manufactured.

<Extrusion molding method of sheet-shaped member for image forming apparatus of the present invention>
Hereinafter, the extrusion molding method of the sheet-shaped member for an image forming apparatus of the present invention, which is suitably adopted for manufacturing the sheet-shaped member for an image forming apparatus of the present invention, will be described with reference to FIG.

FIG. 1 is a schematic cross-sectional view showing a melt extrusion molding step in the extrusion molding method for a sheet-shaped member for an image forming apparatus of the present invention.

In the method of FIG. 1, the pellets to which the above-mentioned lubricant is attached are preferably supplied to the extruder 1 to be melted, and the molten resin is supplied to the annular die 2 to extrude the molten resin (die slip portion) of the annular die 2. ) 3 is extruded into a tube shape, and the inner surface of the tubular extruded product (melted tube) 4 is provided below the annular die 2 in a coaxial manner with the annular die 2 of a cylindrical cooling mandrel (cooling type) 5. A seamless belt-shaped sheet-like member is manufactured by bringing it into contact with the outer peripheral surface and cooling and solidifying it, taking it up with a take-up machine 6, and further cutting it to a desired width with a cutter (not shown).

In the present invention, in such continuous extrusion molding of the internal cooling mandrel method, the frost line of the extruded product (indicated by the broken line F in FIG. 1) is between the lip portion 3 of the annular die 2 and the cooling mandrel 5. The molding conditions are controlled so as to be located at.

Here, the frost line F is a line in which the resin once melted crystallizes in the cooling process. For example, a resin that is transparent in a molten state becomes translucent due to crystallization, so that the molten tube above the frost line is transparent and the tube below the frost line is translucent. Therefore, the frost line can be visually observed as this transparent / translucent boundary line. In the case of a resin mixed with a conductive filler, it can be visually observed as a boundary line changing from high gloss to low gloss.

When the molten resin is cooled and solidified by a cooling mandrel, crystallization becomes insufficient in a rapidly cooled state, and not only the roller habit resistance deteriorates, but also the wear resistance also deteriorates. Therefore, in the present invention, extrusion molding is performed under conditions such that a frost line F is formed between the cooling mandrel 5 and the die slip portion 3 so as to crystallize before the molten tube 4 comes into contact with the cooling mandrel 5. .. By doing so, the inner surface and the outer surface of the extruded product are evenly air-cooled and decooled, the roller habit resistance is improved, and the influence on the crack resistance is reduced, which is preferable.

The preferred position of the frost line F is such that the distance from the die slip portion 3 (L _{1 in} FIG. 1) is 5 mm or more and 60 mm or less, and the more preferable distance is 10 mm or more and 40 mm or less.

The position of the cooling mandrel 5 may be on the downstream side in the extrusion direction from the position of the frost line F, but if it is too far from the position of the frost line F, it crystallizes and solidifies with the diameter of the cooling mandrel 5. Deformation due to the difference in size becomes large at the time of contact with the tube, the extruded product becomes wrinkled, cooling by the cooling mandrel 5 becomes impossible, and roundness cannot be maintained, which is not preferable. Therefore, the distance between the cooling mandrel 5 and the frost line F (L _{2 in} FIG. 1) is preferably 5 mm or more and 100 mm or less, and more preferably 10 mm or more and 60 mm or less.

In this way, in order to form the frost line F between the die slip portion 3 and the cooling mandrel 5, the distance between the cooling mandrel 5 and the annular die 2 (the total distance between _{L 1} and L _{2 in FIG. 1).} ) Is longer than usual, for example, about 20 to 160 mm, and then the extrusion molding conditions and the mold conditions are controlled as follows, for example.
(1) The die temperature was set to about 360 to 410 ° C., which is not extremely higher than the melting point of the PEEK resin used, and the take-up speed of the extruded product was set to 0.7 to 2.0 m / min to reach the cooling mandrel 5. Promote crystallization before
(2) Set the ratio of the die slip diameter to the cooling mandrel diameter to 0.8 or more and 1.2 or less.

As described above, after the frost line F is formed between the die slip portion 3 and the cooling mandrel 5, in order to further control the rapid cooling in the cooling mandrel 5 and gradually cool the cooling mandrel 5, the outer surface of the cooling mandrel 5 is cooled. The temperature is preferably set slightly higher, about 100 to 150 ° C.

<Heat treatment>
The sheet-shaped member for an image forming apparatus molded as described above may be heat-treated after molding, whereby the sheet-shaped member for an image forming apparatus having further improved roller habit resistance can be obtained. ..

In this case, the heat treatment conditions depend on the PEEK resin used, but are usually at a temperature of 50 to 150 ° C., preferably 60 to 130 ° C. for 15 minutes to 5 hours, preferably about 1 hour to 3 hours.

The heat treatment may be performed by applying heat while driving an endless belt-shaped sheet-shaped member by stretching it on two or more rollers, or by mounting the sheet-shaped member on a cylindrical mold. .. Further, the heat treatment may be performed in the state of being cylindrical as it is.

[Physical characteristics and characteristics of sheet-shaped members for image forming equipment]
Suitable physical properties and characteristics of the sheet-shaped member for an image forming apparatus of the present invention are listed below.

<Thickness>
The thickness of the sheet-like member for an image forming apparatus of the present invention varies depending on the application, but is also related to the elastic modulus (here, the elastic modulus is a "tensile elastic modulus" described later), and the elastic modulus is about 3000 MPa. 40 μm or more and 160 μm or less are preferable, and 50 μm or more and 150 μm or less are more preferable. If the thickness is too thick, the thickness deviation will be large. For example, in the case of an endless belt, the peripheral speed of the belt may change, causing image misalignment, and the orientation difference between the surface layer and the central part (central part in the thickness direction). Is too large, the difference in dispersion of the conductive filler and the like is large, and the difference in electrical resistance value is large, which is not preferable. The preferred thickness of the sheet-shaped member is 60 to 140 μm, particularly 70 to 125 μm, because the thickness deviation is small and good molding stability can be obtained in the case of extrusion molding into a tube shape.

<Tension modulus>
The tensile elastic modulus of the sheet-shaped member for an image forming apparatus of the present invention is preferably 1500 MPa or more and 4500 MPa or less. If the tensile elastic modulus is low, for example, in the case of an endless belt, the belt may be scratched by the toner external agent or dust adhering to the roller surface, which is not preferable. Further, for example, when the belt is used as an intermediate transfer belt in an image forming apparatus, the tension may cause a slight elongation, which may cause problems such as color shift. On the other hand, if the tensile modulus is too high, a motor load will be applied when driving the endless belt, so it will be necessary to reduce the thickness setting, and dust will once enter between the roller and the belt, or friction with the photoconductor will occur. It is not preferable because cracks are likely to occur if scratches are formed due to the above, and there is a problem in reliability. Further, in order to improve the transfer efficiency of the toner in the primary transfer, a tensile elastic modulus that does not stretch the belt and that the endless belt does not become stiff is required. A more preferable range of tensile elastic modulus of the sheet-shaped member is 2000 MPa or more and 3500 MPa or less, particularly 2500 MPa or more and 3300 MPa or less.

Specifically, the tensile elastic modulus of the sheet-shaped member of the present invention is measured by the method shown in the section of Examples described later.

<Bending resistance (folding resistance)>
When the sheet-like member for an image forming apparatus of the present invention is used in an image forming apparatus as, for example, an intermediate transfer belt, if the bending resistance is poor, cracks occur and an image cannot be obtained, so that the sheet-like member having good bending resistance is obtained. Members are preferred.

The degree of bending resistance can be quantitatively evaluated by following the measurement method of the number of folding times of JIS P-8115 (2001), and the endless belt with a larger number of folding times is less likely to crack and has excellent bending resistance. It can be judged that there is.
As a specific numerical value, when bent with a jig with R = 2 mm at the tip of the jig, if the number of breaks is 500,000 or more, it can be used as an endless belt by exerting an excellent function. Practically, 750,000 times or more is preferable, and 1 million times or more is more preferable. In the case of a highly elastic belt, if the jig tip R = 0.38 mm according to the JIS standard, the bending is too strong and accurate durability cannot be read. It is preferable that the number of times is 5,000 times or more, particularly 10,000 times or more and less than 20,000 times.

Specifically, the bending resistance (folding resistance) of the sheet-shaped member of the present invention is measured by the method shown in the section of Examples described later.

<Surface electrical resistivity / volume resistivity>
The surface electrical resistivity measured at an applied voltage of 100 V for 10 seconds was measured at SR (100 V), and the surface resistivity measured at an applied voltage of 1000 V for 10 seconds was measured at SR (1000 V) and applied voltage of 100 V for 10 seconds. When the volume resistivity is expressed as VR (100V), the SR (100V) of the sheet-like member for the image forming apparatus of the present invention is not particularly limited, but the intermediate transfer belt is 1 × 10 ⁷ to 1 × 10. ^{It is preferably 12} Ω / □, and more preferably 1 × 10 ⁸ to 1 × 10 ¹¹ Ω / □. The SR (1000 V) of the base material layer ^{is preferably 1 × 10 7} to 1 × 10 ¹² Ω / □, and more preferably 1 × 10 ⁸ Ω to 1 × 10 ¹⁰ Ω / □. Further, the ratio of SR (100V) / SR (1000V) is preferably 100 or less, and when it is 10 or less, the change in the electric resistance value due to the fluctuation of the applied voltage is small, and the toner from the photoconductor to the intermediate transfer belt is transferred. (Primary transfer) and transfer of toner from the intermediate transfer belt to paper (secondary transfer) are performed stably, which is preferable.

In the present invention, the surface electrical resistivity and the volume resistivity are preferably measured by, for example, a UR probe or a UR100 probe manufactured by Dia Instruments Co., Ltd. under the trade name "High Resta UP", but the surface electrical resistivity is 1 ×. In ^{the case of 10 13} Ω or more, it may be measured by a known method such as connecting a JIS electrode to the digital ultra-high resistivity micro ammeter trade name "R8340A" manufactured by Advantest Co., Ltd.

[Use of sheet-shaped members for image forming equipment]
Specific examples of the sheet-like member for an image forming apparatus of the present invention include an endless belt for an image forming apparatus and a paper separating claw for an image forming apparatus.

Of these, the use of the endless belt for an image forming apparatus is not particularly limited, but it can be suitably used in the field of OA equipment, which has strict physical characteristics such as dimensional accuracy, bending resistance, and tensile elastic modulus, and particularly for functional members. When this endless belt has a seamless belt shape, it is suitable because there are few defects such as cracking and stretching.

The endless belt for an image forming apparatus of the present invention is an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, a facsimile machine, and particularly an intermediate transfer belt, a transfer transfer belt, a transfer fixing belt, a fixing belt, and a photoconductor belt. It can be suitably used as a development sleep, particularly as an intermediate transfer belt, a transfer transfer belt, a photoconductor belt and the like.

The endless belt made of the sheet-like member for an image forming apparatus of the present invention may be used as it is as a belt, or may be used by being wound around a drum, a roll, or the like.
Further, for the purpose of improving the cleanability, the surface may be polished and smoothed, or a laminated endless belt in which a coating material is applied to the surface may be used.
Further, for the purpose of reinforcing the end face or the like, a reinforcing tape such as a heat-resistant tape may be attached to the outside and / or inside of the endless belt along the side edges, if necessary.
Further, for the purpose of preventing meandering of the endless belt, a rubber sheet (meandering prevention guide) such as urethane rubber or silicon rubber may be attached to the side edge of the endless belt with an adhesive.
Further, it is preferable to attach the reinforcing tape to the endless belt in combination with the reinforcing tape and then attach the meandering prevention guide because the belt crack resistance prevention effect and the belt meandering prevention effect are obtained.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Material used]
The following materials were used as the molding material for the endless belt.

<Polyetheretherketone resin>
PEEK "3300G" manufactured by Daicel Evonik (for the present invention)
Lowering temperature Crystallization peak temperature T _c = 294.3 ° C
PEEK "2000G" manufactured by Daicel Evonik (for the present invention)
Lowering temperature Crystallization peak temperature T _c = 298.3 ° C
PEEK "650G" manufactured by Victrex (for the present invention)
Lowering temperature Crystallization peak temperature T _c = 294.8 ° C
PEEK "381G" manufactured by Victrex (for comparative example)
Lowering temperature Crystallization peak temperature T _c = 301.1 ° C
PEEK "450G" manufactured by Victrex (for comparative example)
Lowering temperature Crystallization peak temperature T _c = 300.5 ° C
The temperature-decreasing crystallization peak temperature T _c was obtained by DSC measurement of a sheet-like piece obtained by press-molding the purchased raw material at 400 ° C. by the method specified in the present invention.

<Carbon black>
Acetylene Black "Denka Black" manufactured by Electrochemical Co., Ltd.
DBP oil absorption: 180ml / 100g
Specific surface area: 65m ² / g
Volatile content: 0%
Average primary particle size: 39 nm
pH: 9

[Evaluation method]
The evaluation method of the obtained endless belt is as follows.

<DSC (Differential Scanning Calorimetry) Measurement>
Using the product name "SSC-5200" manufactured by Seiko Electronics Co., Ltd., the temperature of the sample was raised to 400 ° C at a temperature rise rate of 10 ° C / min, and then cooled to 23 ° C at 10 ° C / min. The temperature-decreasing crystallization peak temperature T _c was measured.

<Surface electrical resistivity / volume resistivity>
The surface electrical resistivity was measured under the conditions of applied voltages of 100V and 1000V for 10 seconds each using the product name "HIRESTA (UR probe)" manufactured by Dia Instruments Co., Ltd. The surface electrical resistivity when the applied voltage is 100 V is described as "SR (100 V)", and the surface electrical resistivity when the applied voltage is 1000 V is described as "SR (1000 V)".
For the volume resistivity, a value measured at an applied voltage of 100 V with respect to the outer surface of the endless belt was adopted. This volume resistivity is described as "VR (100V)".

<Roller habit restoration rate>
When an endless belt is used as an intermediate transfer belt in an image forming apparatus, for example, when the endless belt is stretched on a roller in a printer and exposed to a high temperature of about 60 ° C. or higher, the endless belt has a roller mark (roller). It is not preferable to have a habit because it affects the image. The roller habit resistance of the endless belt was evaluated by the following method.
An endless belt whose condition has been adjusted for 24 hours or more under the conditions of a temperature of 23 ° C. and a humidity of 50% is cut into a width of 15 mm and a length of 44 mm, and this test piece is used as a roller having a diameter of 14 mm, and the length direction of the test piece is the circumferential direction of the roller. After fixing with cellophane tape or the like and leaving it in a constant temperature and humidity layer at a temperature of 60 ° C. and a humidity of 95% for 2 hours, and then leaving it in an environment of a temperature of 23 ° C. and a humidity of 50% for 24 hours, the test piece is released from the roller. , The value obtained by the following formula from the opening width L of the test piece (the width of the opening of the test piece habituated to have a substantially C-shaped cross section by a roller) when left at a temperature of 23 ° C. and a humidity of 50% for 2 hours. Roller habit restoration rate (%). This value is preferably 70% or more because of its excellent roller habit resistance.
Roller habit restoration rate (%) = {opening width L (mm) / test piece length 44 (mm)} x 100

<Tension modulus>
According to ISO R1184-1970, a test piece having a width of 15 mm and a length of 150 mm was cut out from the endless belt, and the test piece was measured at a tensile speed of 1 mm / min and a distance between grippers of 100 mm.

<Bending resistance (folding resistance)>
In accordance with JIS P-8115 (2001), a test piece having a width of 15 mm and a length of 100 mm is cut from an endless belt, and the test piece is bent at a bending speed of 175 times / minute by a MIT tester. The number of bends leading to each failure was measured using a bending jig having a radius of curvature R = 0.38 mm and 2 mm at the tip under the conditions of a rotation angle of 135 ° to the left and right and a tensile load of 1.0 kgf. As the numerical value, the average value of 3 points was used.

[Examples and Comparative Examples]
<Example 1>
14.5 parts by weight of acetylene black was mixed with 85.5 parts by weight of PEEK "3300G" manufactured by Daicel Ebonic, and pelletized using a twin-screw kneading extruder ("PCM45" manufactured by Ikegai Corp.). The kneading conditions were based on a cylinder temperature of 380 ° C.

Next, 0.05 parts by weight of calcium stearate was adhered to the surface of 100 parts by weight of the pellets of the molding material obtained above with a dry blend, and then dried at 150 ° C. A tubular die is melt-extruded below the annular die by an extruder, and the extruded melt tube is brought into contact with the outer surface (temperature 120 ° C.) of a cooling mandrel having an outer diameter of 231 mm mounted on the same axis as the annular die via a support rod. Next, the cylindrical core installed in the melting tube and the take-up machine installed on the outside held the cylindrical shape of the seamless belt-shaped film while cooling and solidifying it. While taking it in the state, it was sliced into round slices with a length of 300 mm. The basic conditions for both the cylinder and the die temperature were 380 ° C., and the die mold conditions were a die mold lip clearance of 2.0 mm and a take-up speed of 1.0 m / min. An endless belt having an inner diameter of 230 mm was obtained while adjusting the extrusion amount, the extrusion temperature, and the cooling temperature so that the average thickness of the film-like material was 80 μm.

The distance between the die slip part and the cooling mandrel was 55 mm (L ₁ + L ₂ = 55 mm), the frost line was 10 mm (L ₁ = 10 mm) from the die slip part, and it was between the die slip part and the cooling mandrel. ..

Table 1 shows the evaluation results of the obtained endless belt.
As shown in Table 1, cooling crystallization peak temperature _{T c} of the endless belt obtained are 295.6 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. The roller habit restoration rate was 85%, the number of times of folding was 10780 at R = 0.38, and it did not break even at 1 million times at R = 2 mm, and both crack resistance and roller habit resistance were good.

<Example 2>
An endless belt was obtained in the same manner as in Example 1 except that the take-up speed during melt extrusion was set to 1.5 m / min.
The distance between the die slip part and the cooling mandrel was 55 mm (L ₁ + L ₂ = 55 mm), the frost line was _{located 15 mm (L 1} = 15 mm) from the die slip part, and it was between the die slip part and the cooling mandrel. ..

Table 1 shows the evaluation results of the obtained laminated belt.
As shown in Table 1, cooling crystallization peak temperature _{T c} of the endless belt obtained are 294.3 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. The roller habit restoration rate was 80%, the number of times of folding was 11100 times at R = 0.38, and it did not break even at 1 million times at R = 2 mm, and both crack resistance and roller habit resistance were good.

<Example 3>
An endless belt was obtained in the same manner as in Example 1 except that the take-up speed during melt extrusion was set to 1.8 m / min.
The distance between the die slip part and the cooling mandrel is 55 mm (L ₁ + L ₂ = 55 mm), and the crystallization temperature of the frost line is 20 mm (L ₁ = 20 mm) from the die slip part. It was between the cooling mandrel.

Table 1 shows the evaluation results of the obtained laminated belt.
As shown in Table 1, cooling crystallization peak temperature _{T c} of the endless belt obtained are 293.6 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. The roller habit restoration rate was 78%, the number of times of folding was 13000 times at R = 0.38, and it did not break even at 1 million times at R = 2 mm, and both crack resistance and roller habit resistance were good.

<Example 4>
70 parts by weight of PEEK "3300G" manufactured by Daicel Ebonic, 17 parts by weight of PEEK "2000G" manufactured by Daicel Ebonic, and 13 parts by weight of acetylene black are blended to set the take-up speed at the time of melt extrusion to 1.7 m / min. An endless belt was obtained in the same manner as in Example 2 except that the extrusion amount was adjusted so that the thickness was 80 μm.
The distance between the die slip part and the cooling mandrel is 55 mm (L ₁ + L ₂ = 55 mm), and the crystallization temperature of the frost line is 18 mm (L ₁ = 18 mm) from the die slip part. It was between the cooling mandrel.

Table 1 shows the evaluation results of the obtained laminated belt.
As shown in Table 1, cooling crystallization peak temperature _{T c} of the endless belt obtained are 295.6 ° C., thickness 80 [mu] m, SR (100 V) was 4.0 × 10 ⁹ Ω. The roller habit restoration rate was 78%, the number of times of folding was 17,500 at R = 0.38, and it did not break even at 1 million times at R = 2 mm, and both crack resistance and roller habit resistance were good.

<Example 5>
Except that 16 parts by weight of acetylene black was mixed with 84 parts by weight of PEEK "650G" manufactured by Victrex, the take-up speed at the time of melt extrusion was set to 1.0 m / min, and the extrusion amount was adjusted so that the thickness was 80 μm. Obtained an endless belt in the same manner as in Example 2.
The distance between the die slip part and the cooling mandrel is 55 mm (L ₁ + L ₂ = 55 mm), and the crystallization temperature of the frost line is 10 mm (L ₁ = 10 mm) from the die slip part. It was between the cooling mandrel.

Table 1 shows the evaluation results of the obtained laminated belt.
As shown in Table 1, lowering crystallization peak temperature Tc of the endless belt obtained are 292.8 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. The roller habit restoration rate was 80%, the number of times of folding was 16000 times at R = 0.38, and it broke at 700,000 times at R = 2 mm, but it was a usable level, and the roller habit resistance was good.

<Comparative example 1>
15.5 parts by weight of acetylene black was added to 84.5 parts by weight of PEEK "381G" manufactured by Victrex, and pelletized using a twin-screw kneading extruder ("PCM45" manufactured by Ikegai Corp.). The kneading conditions were based on a cylinder temperature of 380 ° C.

Next, 0.05 parts by weight of calcium stearate was adhered to the surface of 100 parts by weight of the pellets of the molding material obtained above with a dry blend, and then dried at 150 ° C. The molten tube is extruded below the annular die in a molten tube state by an extruder, and the extruded molten tube is brought into contact with the outer surface (temperature 90 ° C.) of a cooling mandrel having an outer diameter of 231 mm mounted on the same axis as the annular die via a support rod. Next, the cylindrical core installed in the melting tube and the take-up machine installed on the outside held the cylindrical shape of the seamless belt-shaped film while cooling and solidifying it. While taking it in the state, it was sliced into round slices with a length of 300 mm. The basic conditions for both the cylinder and the die were 380 ° C., and the die conditions were a die mold lip clearance of 2.0 mm and a take-up speed of 1.5 m / min. An endless belt having an inner diameter of 230 mm was obtained while adjusting the extrusion amount, the extrusion temperature, and the cooling temperature so that the average thickness of the film-like material was 80 μm.
The distance between the die slip part and the cooling mandrel was 55 mm (L ₁ + L ₂ = 55 mm), the frost line was _{located 15 mm (L 1} = 15 mm) from the die slip part, and it was between the die slip part and the cooling mandrel. ..

Table 1 shows the evaluation results of the obtained endless belt.
As shown in Table 1, cooling crystallization peak temperature _{T c} of the endless belt obtained are 303.8 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. Since the semi-conductive endless belt had a roller habit restoration rate of 54%, a folding resistance of 3000 times at R = 0.38, and 750,000 times at R = 2 mm, both crack resistance and roller habit resistance reached the target. I didn't.

<Comparative example 2>
An endless belt was obtained in the same manner as in Comparative Example 1 except that the temperature of the outer surface of the cooling mandrel during melt extrusion was set to 120 ° C.
The distance between the die slip part and the cooling mandrel was 55 mm (L ₁ + L ₂ = 55 mm), the frost line was _{located 15 mm (L 1} = 15 mm) from the die slip part, and it was between the die slip part and the cooling mandrel. ..

Table 1 shows the evaluation results of the obtained endless belt.
As shown in Table 1, cooling crystallization peak temperature _{T c} of the endless belt obtained are 303.8 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. The roller habit restoration rate was 82%, but the crack resistance reached the target because the semi-conductive endless belt had a folding resistance of 1000 times at R = 0.38 and 500,000 times at R = 2 mm. There wasn't.

<Comparative example 3>
The endless belt is the same as in Comparative Example 1 except that 16 parts by weight of acetylene black is blended with 84 parts by weight of PEEK "450G" manufactured by Victrex and the temperature of the outer surface of the cooling mandrel during melt extrusion is 120 ° C. Obtained.
The distance between the die slip part and the cooling mandrel was 55 mm (L ₁ + L ₂ = 55 mm), the frost line was _{located 15 mm (L 1} = 15 mm) from the die slip part, and it was between the die slip part and the cooling mandrel. ..

Table 1 shows the evaluation results of the obtained endless belt.
As shown in Table 1, lowering crystallization peak temperature Tc of the endless belt obtained are 300.3 ° C., thickness 80 [mu] m, SR (100 V) was 3.0 × 10 ⁹ Ω. The roller habit restoration rate was 80%, but the crack resistance reached the target because the semi-conductive endless belt had a folding resistance of 4000 times at R = 0.38 and 700,000 times at R = 2 mm. There wasn't.

1 Extruder 2 Circular die 3 Die slip part 4 Melting tube 5 Cooling mandrel 6 Pick-up machine F Frost line

Claims (5)

A sheet-like member used in an image forming apparatus, which contains a polyetheretherketone resin and a conductive filler of less than 19% by weight, and has a temperature-decreasing crystallization peak temperature T _c of 299 measured by the following differential scanning calorimetry. A sheet-like member for an image forming apparatus, characterized in that the temperature is lower than 0.0 ° C.
<Measurement of differential scanning calorimetry>
_{The temperature-decreasing crystallization peak temperature T c} in the process of raising the temperature of the sheet-shaped member to 400 ° C. at a heating rate of 10 ° C./min and then cooling it to 23 ° C. at 10 ° C./min is measured. In claim 1, the number of folds at R = 0.38 mm is 5,000 or more and less than 20,000, and the number of folds at R = 2 mm is 500,000, which is measured by the following measurement of the number of folds. A sheet-like member for an image forming apparatus, which is characterized by the above.
<Measurement of folding resistance>
In accordance with JIS P-8115 (2001), a test piece having a width of 15 mm and a length of 100 mm is cut from a sheet-shaped member, and the test piece is bent at a bending speed of 175 times / minute by a MIT tester. Using a bending jig with a radius of curvature R = 0.38 mm and 2 mm at the tip of the tip under the conditions of a rotation angle of 135 ° to the left and right and a tensile load of 1.0 kgf, the number of bends leading to each breakage is measured. The average value of the measured values at three points is defined as the number of folding resistances. The sheet-like member for an image forming apparatus according to claim 1 or 2, wherein the roller habit restoration rate determined by the following measurement of the roller habit restoration rate is 70% or more.
<Measurement of roller habit restoration rate>
A sheet-like member whose condition has been adjusted for 24 hours or more under the conditions of a temperature of 23 ° C. and a humidity of 50% is cut into a 15 mm width and a 44 mm length to form a test piece, and this test piece is placed on a roller having a diameter of 14 mm in the test piece length direction. Is fixed so that When the test piece was released from the roller and left at a temperature of 23 ° C. and a humidity of 50% for 2 hours, the roller habit restoration rate was calculated from the width L of the opening of the test piece, which was habituated by the roller to have a substantially C-shaped cross section. %) Is calculated.
Roller habit restoration rate (%) = {opening width L (mm) / test piece length 44 (mm)} x 100 The sheet-like member for an image forming apparatus according to any one of claims 1 to 3, wherein the endless belt or the paper separating claw is used. The sheet-like member for an image forming apparatus according to any one of claims 1 to 4, wherein the conductive filler is acetylene black.

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