JP2011191691A - Sliding member and image fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet type sliding member, which has high durability against wear and is hardly torn, for an image fixing device. <P>SOLUTION: In the sheet type sliding member 6, the proceeding of wear in a woven cloth due to rubbing between respective threads is suppressed by performing heat treatment in a state of the cloth woven with threads containing the fibers of fluorocarbon resin at a temperature equal to or higher than the melting point of the fluorocarbon resin to induce fusion at the intersection of respective threads. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sliding member used for a sliding portion of a machine part. More specifically, it is a sheet-like sliding member disposed on a sliding surface of a machine part, for example, a sliding member used in combination with a liquid lubricant such as oil. This sliding member is suitably used for an image fixing apparatus such as a copying machine, a printer, a facsimile machine, or the like.

  For example, in a copying machine, a photoconductor formed in a drum shape is uniformly charged, and the photoconductor is exposed to light controlled based on image information to form an electrostatic latent image (toner) on the photoconductor. Then, the toner is transferred onto a recording medium such as paper in an unfixed state by an image fixing device, and fixed on the recording medium by heating / pressing.

  For example, Patent Document 1 describes an image fixing device that includes a pressure roll that is rotatably disposed and a cylindrical endless belt that is rotatably pressed against the pressure roll. A pressure member that presses the endless belt toward the pressure roll side is provided inside the endless belt, and a porous resin member (sliding member) containing a lubricant is provided between the pressure member and the endless belt. ) And is responsible for smoothly rotating the endless belt.

  As an example of the material used as the sliding member, Patent Document 2 describes using a cloth woven with porous yarn. In Patent Document 2, porous PTFE fibers obtained by a stretching method are used.

Japanese Patent Laid-Open No. 2001-228731 (FIG. 1) JP2003-191389 (paragraph 0008 etc.)

  However, in the conventional sliding member as described above, the sliding member may be broken due to wear while continuing to be used.

  The present invention has been made under the above-described circumstances, and an object thereof is to provide a sliding member that is not easily torn because of high resistance to wear. It is another object of the present invention to provide an image fixing apparatus that can be operated without a failure for a long time by using the sliding member.

  The sliding member of the present invention that can achieve the above object is a sliding member having a cloth woven with a yarn containing a fluororesin fiber, and the cloth is heat-treated.

  In the sliding member, the thread may include a polytetrafluoroethylene fiber, and the temperature of the heat treatment may be set to 327 ° C. or higher and 400 ° C. or lower.

  The said sliding member WHEREIN: The said thread | yarn contains the fiber of a polytetrafluoroethylene, It can be set as the aspect which makes the temperature of the said heat processing 240 degreeC or more and less than 327 degree | times.

  In the sliding member, it is desirable to use expanded polytetrafluoroethylene as the polytetrafluoroethylene.

  In the sliding member, it is preferable that the fiber contains two or more kinds of fluororesins.

  In the sliding member, it is preferable that the yarn is a bundle including a plurality of fibers, and a lubricant is attached to the cloth.

  The image fixing apparatus of the present invention that can achieve the above object includes the above sliding member.

  In this invention, it is a sliding member which has the cloth woven with the thread | yarn containing the fiber of a fluororesin, Comprising: The said cloth is heat-processed. With this sliding member, it is possible to provide an image fixing device that can be operated with low frictional resistance over a long period of time.

FIG. 1 is a cross-sectional view of an image fixing apparatus according to Embodiment 1 of the present invention. FIG. 2 is a sketch of a microscopic observation image of a sliding member cross section in an example of the present invention.

(Embodiment 1)
Hereinafter, an image fixing apparatus according to a first embodiment of the present invention will be described with reference to the drawings. However, the first embodiment is mainly intended to explain a usage example of the sliding member of the present invention. The image fixing apparatus using the sliding member of the present invention is not limited to this. The sliding member of the present invention is used in any general image fixing apparatus that requires a sliding member.

  FIG. 1 is a cross-sectional view of an image fixing apparatus using a sliding member of the present invention. In FIG. 1, the image fixing device has a configuration in which a fixing roll 1 and a heating roll 2 are pressed against each other while rotating in the direction of an arrow. The paper 9 with the toner 9 (unfixed) adhered is sandwiched between the fixing roll 1 and the heating roll 2 and heated / pressed, whereby the toner 9 is fixed.

  The fixing roll 1 has an endless belt 1a and a pressing portion 5 formed therein. On the outer surface of the endless belt 1a, a material excellent in releasability such as perfluoroalkoxy fluororesin (PFA), polytetrafluoroethylene resin (PTFE), and the like is formed.

  A core member 4 is provided inside the endless belt 1a so as to be rotatable with respect to the endless belt 1a. A pressing portion 5 is fixed to the core member 4, and a sliding member 6 formed of a woven fabric is fixed to the tip of the pressing portion 5. That is, the sliding member 6 is located between the pressing portion 5 and the inner side surface of the endless belt 1a and is fixed to the pressing portion 5, but is only pressed against the endless belt 1a. It is free to move. Lubricant adheres to the woven fabric constituting the sliding member 6 to enhance the sliding property with the endless belt 1a. The sliding member 6 will be described in detail in a second embodiment described later.

  Furthermore, a porous material lubricant supply member 7 impregnated with a lubricant is attached to the core member 4. The lubricant in the lubricant supply member 7 is sequentially supplied to the sliding member 6 by the rotation of the endless belt 1a.

  The heating roll 2 is provided with a cylindrical portion 2a (stainless layer / elastic layer / release layer) in order from the inner side. A halogen lamp 3 as a heating source is disposed inside the cylindrical portion 2a. Examples of the constituent material of the elastic layer include silicone rubber and fluoro rubber.

  The above is the outline of the image fixing apparatus using the sliding member of the present invention. Next, the sliding member of the present invention will be described in detail.

(Embodiment 2)
Hereinafter, the sliding member concerning Embodiment 2 of this invention is demonstrated. The sliding member of the present invention is a sliding member having a cloth woven with a yarn containing a fluororesin fiber as described above, and the cloth is heat-treated. Therefore, in the following, (1) yarns containing fluororesin fibers, (2) woven cloth, and (3) heat treatment will be described in order.

(1) Fluororesin Fiber The woven fabric yarn used in the present invention contains a fluororesin fiber. Examples of the fluororesin fiber include porous polytetrafluoroethylene (PTFE) fiber, non-porous PTFE fiber, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) fiber, and tetrafluoroethylene / hexafluoropyruvylene. Copolymer (FEP) fiber, tetrafluoroethylene / ethylene copolymer (ETFE) fiber, polychlorotrifluoroethylene (PCTFE) fiber, chlorotrifluoroethylene / ethylene copolymer (ECTFE) fiber, polyvinylidene fluoride ( PVDF) fibers, polyvinyl fluoride (PVF) fibers, and the like. In addition, these fluororesin fibers or a combination of these fluororesin fibers with other organic fibers (nylon, polyester, aramid, etc.) and inorganic fibers as appropriate can be used. Among these, it is preferable to use polytetrafluoroethylene from the viewpoint of improving slidability and wear resistance. Further, from the viewpoint of increasing the strength of the fiber, it is preferable to use a stretched polytetrafluoroethylene.

  For example, porous polytetrafluoroethylene (porous PTFE) is made by mixing and molding PTFE fine powder and molding aid, removing the molding aid, stretching at a high temperature and high speed, and further firing if necessary. Obtained by. A fibrous material can be formed by finely breaking the obtained porous polytetrafluoroethylene along the stretching direction.

  In order to maintain the minimum strength, it is desirable that the fluororesin fiber is, for example, 10 denier or more (more preferably 20 denier or more, further preferably 30 denier or more) (0.9 denier is 1 decitex). As will be described later, if a woven fabric is formed using yarns made of a bundle of fluororesin fibers, the lubricant is not only between the bundles of fluororesin fibers but also between the fluororesin fibers and the fluororesin fibers. The retention of the lubricant is improved by entering. In order to exhibit such an effect more effectively, it is desirable that the fluororesin fiber is, for example, 100 denier or less (more preferably 80 denier or less, further preferably 70 denier or less).

(2) Woven cloth As described above, the sliding member of the present invention is a cloth woven with yarns containing fluororesin fibers (hereinafter sometimes referred to as “woven cloth” or simply “cloth”). It is what you have. From the viewpoint of improving slidability, a lubricant such as oil is usually attached to the woven fabric.

  The cloth used in the present invention is a cloth woven with the above-mentioned yarn containing the fluororesin fiber, and there is no particular limitation on the weaving method, but examples include plain weave, satin weave, twill weave, leash weave and imitation weave. it can. In the present invention, plain weave or satin weave is preferred from the viewpoint of wear resistance and slidability. From the viewpoint of the strength and handleability of the woven fabric, the thickness of the woven fabric is 0.1 to 1 mm, more preferably 0.2 to 0.5 mm.

  In addition, when the woven fabric in this invention is comprised by a plain weave, it is desirable to use at least one of a warp and a weft as a twisted yarn.

(3) Heat treatment The woven fabric in the present invention is heat-treated. That is, the object to be heat-treated is cloth. Therefore, the present invention does not prescribe any heat treatment for the yarn before weaving into the cloth state, but prescribes the heat treatment after weaving into the cloth state. When a fabric woven with yarn containing fluororesin fibers is heat-treated, the yarn shrinks, and the yarns are firmly joined so that the entire woven fabric is tightened, and the weight of the woven fabric, that is, the basis weight. The resistance to tearing is improved by increasing the amount.

  When the yarn is made of polytetrafluoroethylene fiber, if the temperature of the heat treatment is higher than the melting point of polytetrafluoroethylene, that is, 327 ° C. or higher, fusion occurs at the intersection of the yarn and the yarn. Progress of abrasion of the woven fabric due to rubbing can be suppressed. In order to exhibit such an effect more reliably, the temperature of the heat treatment is preferably 350 ° C. or higher, more preferably 360 ° C. or higher. On the other hand, when the temperature of the heat treatment is too high, the texture of the woven fabric disappears or the surface of the woven fabric is wavy (undulated), so the upper limit of the heat treatment temperature is 400 ° C (preferably 390 ° C, more preferably 380 degrees).

  Of course, the temperature of the heat treatment may be a temperature lower than the melting point of polytetrafluoroethylene. In this case, the yarns are not fused, but the resistance to tearing is improved by shrinking the yarn as described above. In order to exhibit such an effect more reliably, the temperature of the heat treatment is set to 240 ° C. or more, for example. Preferably it is 250 degree | times or more, More preferably, it is 260 degree | times or more.

  The method for heat-treating the woven fabric is not particularly limited. For example, a belt-shaped woven fabric is prepared, and a winding roll is used while contacting the woven fabric with a rotating body (heating rotating body) having a heater inside. There is a method in which the woven fabric is heat-treated continuously by rewinding sequentially. This method has the advantage of high production efficiency and stability. At that time, it is desirable that the woven fabric is uniformly brought into contact with the heating rotator and the woven fabric is uniformly shrunk. Alternatively, a method may be employed in which a heat treatment is performed by winding a plurality of woven fabrics around a metal cylindrical object and placing them in a thermostat for a certain period of time.

  As described above, by heat-treating a cloth woven with a yarn containing a fluororesin fiber, a sliding member that does not easily break even when used for a long time can be obtained. By using such a sliding member as a basic configuration and further adding the characteristics described below, a sliding member having even better characteristics can be obtained.

(lubricant)
As described above, the sliding resistance of the sliding member can be lowered by holding the lubricant in the sliding member. The lubricant includes oil and grease, but it is preferable to use oil from the viewpoint of lubricity. In the case of oil, silicone oil, fluorine oil or the like is used, but fluorine oil is preferably used from the viewpoint of performance. When silicone oil is used, modified silicone oils such as amino-modified silicone oil, dimethyl silicone oil, mercapto-modified silicone oil, and hindered amine oil are preferable because of excellent slidability and durability. In this case, the viscosity (normal temperature) of the silicone oil is desirably 50 cps or more (more preferably 100 cps or more, more preferably 300 cps or more), 3000 cps or less (more preferably 1000 cps or less, more preferably 500 cps or less). . This is because if the viscosity is less than 50 cps, the evaporation of the silicone oil increases, and if the viscosity exceeds 3000 cps, the sliding resistance increases and the effect of using the lubricant cannot be obtained.

(Fiber bundle)
The yarn used in the present invention is a yarn containing a fluororesin fiber as described above. However, if the fibers are bundled, the lubricant is likely to enter and be held between the fibers. In order to improve the retention of the lubricant, it may be possible to make the woven fabric using a finer single thread to reduce the distance between the yarn, but in this case the strength of the woven fabric itself is insufficient. There is a problem to do. When the yarn is thin, it is considered that the strength is lowered even if the total fineness (number of deniers) is the same because each yarn is easily broken. In addition, when the yarn is thin, the unevenness of the surface of the woven fabric is reduced due to wear, and the contact area during sliding is increased, so that the frictional resistance is increased from a very early stage after the start of use. Therefore, in the present invention, a fiber bundle is used.

  More specifically, the fiber bundle refers to a plurality of fluororesin short fibers (2 or more (preferably 8 or more, more preferably 15 or more), 100 or less (preferably 80 or less, more preferably 50). The following))) are collected and bundled, and include, for example, a simple bundle of short fibers and a twisted bundle of short fibers.

  Considering the balance between the thickness of one fiber and the number of fibers contained in the fiber bundle, it is preferable that 10 to 100 denier stretched fluororesin fibers are bundled, and one fiber bundle is 200 denier or more. Further, as an optimum range, it is possible to bundle 10 to 50 denier fibers (stretched PTFE fibers) and to make one fiber bundle 200 to 1000 deniers, which balances strength and lubricant retention. good.

(Resin film)
Moreover, you may use as a sliding member what fixed and integrated the resin film on the single side | surface (the pressing part 5 side and the opposite side to a sliding surface) of a woven fabric. This resin film is effective in preventing deformation of the woven fabric. When the resin film is not used, the woven fabric may be deformed by using for a long time and may cause various inconveniences. However, the use of the resin film can prevent such inconveniences from occurring. The amount of deformation of the woven fabric varies depending on the material of the woven fabric and the structure of the woven fabric, but the effect of using the resin film is more remarkable as the deformation is larger. By using the resin film, the amount of deformation is relatively large. Even when a cloth is used, the stability over time is good.

  As the resin film used in the present invention, various porous and non-porous resin films, metal films, and the like are used. From the viewpoint of lubricant blocking property, workability, and cost, a non-porous resin film is used. Is preferred. If a non-porous resin film is used, when the lubricant is held in the woven fabric used in the present invention, the resin film is not formed even if a pressing portion 5 made of, for example, silicone rubber is used at the lower portion of the woven fabric. It functions as a barrier layer of the lubricant, and the phenomenon that the lubricant wets the pressing portion 5 and causes the swelling and deterioration of the pressing portion 5 can be prevented. Specific examples of the material used for the resin film include, for example, fluororesin such as PTFE, PFA, FEP, ETFE, polyethylene terephthalate (PET), polyimide (PI), polyetherimide (PEI), polyethersulfone. (PES), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyethylene naphthalate (PEN), liquid crystal polymer (LCP) and the like.

(Porous film)
On one side (sliding surface side) or both surfaces of the woven fabric or the woven fabric integrated with the resin film, a porous film (porous film) is provided in terms of reducing sliding resistance and improving wear resistance. ) May be laminated and adhered. The porous film is not particularly limited as long as it can retain a lubricant and can withstand the operating temperature of the sliding member, but various fluororesin porous films having excellent sliding properties are preferably used. It is done. In the case of the present invention, porous PTFE is particularly preferably used from the viewpoints of heat resistance, wear resistance, slidability, and oil retention. Although the thickness of a porous film is 1-1000 micrometers, 5-150 micrometers is preferable from the point of the handleability as the film, intensity | strength, and cost. The maximum pore diameter of the porous film is preferably 0.01 μm or more from the viewpoint of wear resistance, slidability, and lubricant retention. When the maximum pore diameter is smaller than 0.01 μm, the lubricant retention of the film is lowered. The upper limit value of the maximum pore diameter is not particularly limited as long as the lubricant retention, wear resistance, and slidability are not impaired. The porous PTFE film can be produced by a conventionally known method such as a stretching method, a solvent extraction method, or a casting method. A stretched porous PTFE film produced by a stretching method has high strength and excellent wear resistance, and is particularly preferably used. As a method for producing a porous PTFE film by the stretching method, a conventionally known method disclosed in JP-A No. 46-7284, JP-A No. 50-22881, JP-A No. 03-504876, or the like is used. Can be used.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

1. Production of Sample As a fiber bundle (yarn) used in the examples of the present invention, Japan Gore-Tex Co., Ltd. (product number: Y006TO) was used. This uses a fiber produced by finely tearing a stretched porous polytetrafluoroethylene in the stretching direction. The torn expanded porous polytetrafluoroethylene fibers average 40 denier. On average, 15 such porous polytetrafluoroethylene fibers are bundled to form a 600 denier fiber bundle (one yarn) A. For reference, FIG. 2 shows a sketch of a microscope observation image of the cross-section of the sliding member (enlarged fiber bundle 12 composed of fibers 11).

  In addition, the porous polytetrafluoroethylene is torn so that the average of the porous polytetrafluoroethylene fibers is 20 denier, and an average of 15 fibers are bundled to form a 300 denier fiber bundle (one yarn) B. did.

  Further, the porous polytetrafluoroethylene was used as it was as the yarn C without tearing.

  Using these fiber bundles A and B or yarns C, woven fabric samples of the following comparative examples and examples were prepared.

(Comparative Example 1)
The fiber bundle A was plain woven to produce a woven fabric having a thickness of 0.3 to 0.4 mm.

(Comparative Example 2)
The fiber bundle B was plain woven to produce a woven fabric having a thickness of 0.2 to 0.3 mm.

(Comparative Example 3)
A woven fabric having a thickness of 0.35 to 0.45 mm was prepared by making the yarn C into a plain weave.

Example 1
A woven fabric (using fiber bundle A) produced in the same manner as in Comparative Example 1 was brought into contact with a heating rotator having a surface temperature of 360 ° C. for 2 minutes evenly at a treatment speed of 0.1 m / min. Was given. As a result, a woven fabric heat-treated at a temperature higher than the melting point of the stretched porous polytetrafluoroethylene was obtained.

(Example 2)
A woven fabric (using fiber bundle B) produced in the same manner as in Comparative Example 2 was used, and the other conditions were heat-treated as in Example 1.

(Example 3)
A woven fabric having a thickness of 0.35 to 0.45 mm was prepared by making the yarn C into a plain weave, and this was subjected to heat treatment in the same manner as in Example 1.

Example 4
A woven fabric produced in the same manner as in Comparative Example 1 was uniformly contacted with a heated rotating body having a surface temperature of 250 ° C. and subjected to continuous treatment at a treatment speed of 0.1 m / min. As a result, the microporous shrinkage occurred in the stretched porous polytetrafluoroethylene.

(Example 5)
A woven fabric produced in the same manner as in Comparative Example 2 was used, and heat treatment was performed in the same manner as in Example 4 under other conditions.

2. Abrasion test Each of the woven fabrics of Examples 1 to 5 and Comparative Examples 1 to 3 was cut into a size of width 25 mm × length 80 mm, and placed on a curved surface member of R45 mm so that a load was applied to the intermediate portion in the length direction. A load of 300 g was added to this and pressed against the friction mating member. A horizontally movable stage was used as the friction counterpart member. A polyimide film was placed on the stage on the stage to be brought into contact with the woven fabric to be measured. The abrasion test was performed by reciprocating the stage with a stroke of 100 mm length.

  As can be seen from Table 1, in Comparative Examples 1 to 3, breakage occurred in the woven fabric before the stage was reciprocated 20,000 times. On the other hand, in Examples 1 to 5 in which the heat treatment was performed on the woven fabric, the fracture occurred even after reciprocating 20,000 times regardless of whether the temperature of the heat treatment was higher than or lower than the melting point of polytetrafluoroethylene. It was confirmed that the wear resistance was improved. However, in Example 5 in which the heat treatment is 240 degrees or more (temperature at which significant shrinkage occurs in the woven fabric) but less than the melting point and the fiber bundle B is composed of relatively thin fibers, Because of this rubbing, tearing occurred after the stage was further reciprocated 10,000 times (a total of 30,000 times).

  As described above, it was confirmed that a very useful sliding member can be obtained by heat-treating a cloth woven with yarns containing fluororesin fibers.

  The sample woven fabric was also subjected to a tensile test, and the results are also shown in Table 1. The test method is as follows. Each woven fabric sample was processed into a JIS-K7127 No. 5 dumbbell shape, and the tensile strength (tensile speed: 50 mm / min) was measured according to JIS-K7161. As can be seen from Table 1, it was confirmed that Examples 1 and 4 subjected to the heat treatment had improved tensile strength as compared with Comparative Example 1 where the heat treatment was not performed. Similarly, in the case of Example 2 and Example 5 where heat treatment was performed, the tensile strength was higher than that in Comparative Example 2 where heat treatment was not performed, and in the case of Example 3 where heat treatment was performed. It was confirmed that the tensile strength was higher than that in Comparative Example 3 where heat treatment was not performed.

  Moreover, in Example 1 which performed the heat processing more than melting | fusing point of polytetrafluoroethylene, compared with Example 4 which was the grade which polytetrafluoroethylene contracts and heat-processed below melting | fusing point, it has a tensile strength. It was confirmed to be high. In Examples 1 and 4 using a 600 denier fiber bundle A, it was confirmed that the tensile strength was higher than in Examples 2 and 5 using a 300 denier fiber bundle B.

DESCRIPTION OF SYMBOLS 1 Fixing roll 1a Endless belt 2 Heating roll 2a Cylindrical part 3 Halogen lamp 4 Core member 5 Pressing part 6 Sliding member 7 Lubricant supply member 8 Paper 9 Toner 11 Fiber 12 Fiber bundle

Claims (7)

  A sliding member having a cloth woven with a yarn containing a fluororesin fiber, the cloth being heat-treated.   The sliding member according to claim 1, wherein the yarn includes a polytetrafluoroethylene fiber, and the temperature of the heat treatment is 327 ° C. or more and 400 ° C. or less.   The sliding member according to claim 1, wherein the yarn includes a polytetrafluoroethylene fiber, and the temperature of the heat treatment is 240 degrees or more and less than 327 degrees.   The sliding member according to claim 2 or 3, wherein the polytetrafluoroethylene is expanded polytetrafluoroethylene.   The sliding member according to any one of claims 1 to 4, wherein the fiber includes two or more kinds of fluororesins.   The sliding member according to claim 1, wherein the yarn is a bundle including a plurality of fibers, and a lubricant is attached to the cloth. An image fixing device comprising the sliding member according to claim 1.

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