JP2009116273A - Fluororesin-coated belt and manufacturing method therefor, image fixing device, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluororesin-coated belt capable of restraining satisfactorily a satin finish defect from being generated, even when an unfixed image is pressed, and to provide a method of manufacturing the fluororesin-coated belt capable of obtaining easily the fluororesin-coated belt. <P>SOLUTION: The fluororesin-coated belt includes a base material, an elastic layer, and a mold release layer comprising a fluroresin annular body, in this order, and has a surface of which the dynamic micro hardness is 1.00 or less, in a side formed with the mold release layer. The method of manufacturing the fluororesin-coated belt has a step of forming the elastic layer on the base material, a fluororesin coating step of forming the mold release layer by coating the fluroresin annular body onto the elastic layer, and a step of applying stretching processing to the mold release layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluororesin-coated belt, a manufacturing method thereof, an image fixing device, and an image forming apparatus.

  In recent years, in an image fixing apparatus for an electrophotographic apparatus, a heating member is disposed on the inner surface of a fixing belt, and a pressing member such as a roller is pressed through the heating member to form a pressing region. A method is employed in which a recording medium on which an unfixed image such as a toner image is transferred is nipped and conveyed to be fixed.

  As the fixing belt, a fixing belt in which an elastic layer made of rubber or the like is provided around a belt base material and a fluororesin is coated on the outer periphery of the elastic layer is beginning to be used. In addition, as the speed increases, a fixing member having a larger diameter has been desired. As a method of coating the outer peripheral surface of the belt base material having the elastic layer with a fluororesin, the following methods have been conventionally employed. It was.

First, as a first method, there is known a method in which a fluororesin powder or liquid paint is applied to the outer periphery of an elastic layer and then baked to form a fluororesin release layer.
As a second method, an adhesive is applied to the outer peripheral surface of the elastic layer, and then a heat-shrinkable annular body made of a fluororesin is covered, and this heat-shrinkable annular body is heat-welded with a heater such as a dryer. (The heating at this time is usually performed at a temperature of 320 ° C. or higher and 380 ° C. or lower.) A method of bonding to the elastic layer is known.

Further, as a third method, a fluororesin annular body and a belt base material not provided with an elastic layer on the outer periphery are concentrically attached in a hollow cylindrical mold, and the fluororesin annular A method is known in which an elastic layer material is injected into a region sandwiched between a body and a belt base material and cured.
Further, as a fourth method, an adhesive is applied to the outer peripheral surface of the elastic layer, and then a fluororesin annular body having an inner diameter smaller than the outer diameter of the belt base material on which the elastic layer is formed is expanded. There is a method in which the belt base material is inserted and covered with a contraction force of a fluororesin annular body.

Among these fluororesin coating methods, in recent years, research on the fourth method has been extensively conducted. For example, after coating a fluororesin annular body, an O-shaped ring is used to form the fluororesin annular body. A method of handling the surface has been tried (see, for example, Patent Document 1).
Further, when the belt substrate is coated with a fluororesin annular body to form a release layer, the fluororesin annular body is improved in order to improve the adhesion between the elastic layer and the fluororesin annular body. A method of roughening the inner peripheral surface of the material is used (for example, see Patent Document 2).
JP 2002-36361 A Japanese Patent Laid-Open No. 5-166956

  When a toner image on a recording medium is fixed using an image fixing device provided with a fixing belt, a satin-like defect (a pear-like surface-like defect) may occur. The satin-like defects are caused by irregular reflection of light in the concave portions because even if the unfixed toner image is crushed, the irregularities on the surface of the toner image cannot be leveled and the concave portions remain. .

  The present invention has been made in view of the above-described problems. That is, an object of the present invention is to provide a fluororesin-coated belt that suitably suppresses occurrence of a satin-like defect even when an unfixed image is pressed, and the fluorine It is an object of the present invention to provide a fluororesin-coated belt manufacturing method capable of easily obtaining a resin-coated belt, an image fixing device and an image forming apparatus capable of obtaining a good fixed image.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1 is provided with a substrate, an elastic layer, and a release layer made of a fluororesin annular body in this order, and the surface of the surface on which the release layer is formed has a dynamic microscopic surface. It is a fluororesin-coated belt having a hardness of 1.00 or less.

  The invention according to claim 2 is the fluororesin-coated belt according to claim 1, wherein the dynamic micro hardness is 0.5 or less.

The invention according to claim 3 is the aspect according to claim 1 or claim 2, in which a 50 mm × 25 mm rectangular test piece having a long side in the circumferential direction is cut out and the test piece is arranged on a plane. This is a fluororesin-coated belt in which the state of warping is the following (c) or (d).
(C) No warping / returning (d) Warping to the belt inner surface side

  The invention according to claim 4 is a fluororesin-coated belt in which the elastic layer according to any one of claims 1 to 3 has a thickness of 0.1 mm to 0.5 mm.

  The invention according to claim 5 is an elastic layer forming step of forming an elastic layer on a substrate, and a fluororesin coating step of forming a release layer by coating a fluororesin annular body on the elastic layer. And a stretching step of subjecting the release layer to a stretching process.

  The invention according to claim 6 includes the fluororesin-coated belt according to any one of claims 1 to 4 and a pressure rotator disposed to face the fluororesin-coated belt. An image fixing device.

  The invention according to claim 7 is an image holding member, a toner image forming unit that forms a toner image on the surface of the image holding member, a transfer unit that transfers the toner image onto a recording medium, and And an image forming apparatus having fixing means for fixing the transferred toner image onto a recording medium using an image fixing apparatus.

  According to the first aspect of the present invention, it is possible to suitably suppress the occurrence of a satin-like defect even when an unfixed image is pressed.

  According to the second aspect of the present invention, it is possible to more suitably suppress the occurrence of a satin-like defect even when an unfixed image is pressed.

  According to the third aspect of the present invention, it is possible to more suitably suppress the occurrence of a satin-like defect even when an unfixed image is pressed.

  According to the invention which concerns on Claim 4, the favorable flexibility as a belt can be obtained further.

  According to the fifth aspect of the present invention, it is possible to easily obtain a fluororesin-coated belt that can suitably suppress the occurrence of a textured defect even when an unfixed image is pressed.

  According to the invention of claim 6, a good fixed image can be obtained.

  According to the seventh aspect of the invention, a good fixed image can be obtained.

<Fluorine resin coated belt>
Hereinafter, the fluororesin-coated belt according to the first embodiment which is a preferable aspect will be described in detail with reference to the drawings. As shown in FIG. 1, the fluororesin-coated belt according to the first embodiment has an elastic layer 20 and a fluororesin annular body (hereinafter simply referred to as “fluororesin tube”) on the surface of a cylindrical base material 30. And a release layer 10 made of
The fluororesin-coated belt according to the first embodiment can be suitably used as a belt member in an electrophotographic image forming apparatus, and can be particularly suitably used as a fixing belt in an image fixing apparatus, for example.

  In the fluororesin-coated belt according to the first embodiment, the dynamic microhardness of the surface on the side where the release layer 10 is formed is 1.00 or less, and more preferably 0.50 or less.

Here, the dynamic micro hardness can be obtained by a method of measuring how much the indenter has entered the sample. When the test load P (mN) and the amount of penetration of the indenter into the sample (indentation depth) D (μm), the surface microhardness DH is defined by the following formula (A).
Formula (A) DH≡αP / D ²
In the formula (A), α is a constant depending on the shape of the indenter, and α = 3.8854 (used indenter: in the case of triangular pyramid indenter).

  This dynamic microhardness is the hardness obtained from the load and indentation depth in the process of indenting the indenter, and represents the strength characteristics of the material in a state that includes not only plastic deformation but also elastic deformation. is there. In addition, the measurement area is very small, and more accurate hardness measurement is possible within a range close to the toner particle diameter.

In this specification, the dynamic micro hardness on the surface of the fluororesin-coated belt was determined by the following method. The fluororesin-coated belt is cut into about 5 mm square, and a small piece is fixed to the glass plate with an instantaneous adhesive. The dynamic microhardness of the surface of this sample is measured using a microhardness meter DUH-201S (manufactured by Shimadzu Corporation). The measurement conditions are as follows.
Measurement environment: 23 ° C, 55% RH
Working indenter: Triangular pyramid indenter Test mode: 3 (soft material test)
Test load: 0.70 gf
Load speed: 0.0145 gf / sec
Holding time: 5 sec

In the fluororesin-coated belt according to the first embodiment, the thickness of the elastic layer 20 is preferably 0.1 mm or more and 0.5 mm or less, and particularly preferably 0.1 mm or more and 0.3 mm or less. Although not particularly limited, it is generally preferable that the thickness of the base material 30 is 0.05 mm or more and 0.15 mm or less. The thickness of the release layer 10 is preferably 15 μm or more and 100 μm or less.
The outer diameter, axial length, etc. of the fluororesin-coated belt can be freely designed according to the mode to be used.

-Warping back test-
In the fluororesin-coated belt according to the first embodiment, it is preferable that the state of warping of the test piece observed by the following test method is the following state (c) or (d).
More specifically, as shown in FIG. 2A, first, a 50 mm × 25 mm rectangular test piece having a long side in the circumferential direction is taken from the fluororesin-coated belt 70 (thickness is equal to the thickness of the fluororesin-coated belt). 72 is cut out, and the test piece 72 is arranged on a flat surface (for example, a flat plate 74) with the outer peripheral surface side facing up. The state of warping at that time is preferably not the state of warping to the belt outer peripheral surface side as shown in FIG. 2B but the state of (c) or (d) below.
(C) No warping and returning (for example, the state shown in FIG. 2C)
(D) Warping toward the inner peripheral surface of the belt (for example, the state shown in FIG. 2D)

  As shown in FIG. 2B, when the belt is warped toward the outer peripheral surface of the belt, the cylindrical base material 30 and the elastic layer 20 are in a state of being pulled by the release layer (fluororesin tube) 10. Since the state of the base material 30, the elastic layer 20, and the release layer (fluororesin tube) 10 does not change between the form of the test piece 72 and the form of the fluororesin-coated belt 70, the form of the fluororesin-coated belt 70 is separated. It can be said that the mold layer (fluororesin tube) 10 is being pulled. On the other hand, as shown in FIG. 2 (C) and FIG. 2 (D), when there is no warping or warping toward the belt inner peripheral surface side, it can be said that there is no tension by the release layer (fluororesin tube) 10. .

<Method for producing fluororesin-coated belt>
The manufacturing method of the fluororesin-coated belt according to the second embodiment includes an elastic layer forming step of forming an elastic layer on a base material, and a mold release by covering the elastic layer with an annular body made of a fluororesin. A fluororesin coating step for forming a layer; and a stretching step for subjecting the release layer to stretching.

  The fluororesin-coated belt according to the first embodiment described above can be obtained by the method for producing a fluororesin-coated belt according to the second embodiment having a stretching process.

  The manufacturing method of the fluororesin-coated belt according to the second embodiment is a cylindrical base material in which an elastic layer is previously formed (refers to the base material 30 and the elastic layer 20 in FIG. And a coating process for covering the surface of the elastic belt substrate with a fluororesin tube, and stretching treatment for the covered fluororesin tube (that is, the release layer 10). And a stretching step for applying.

  In addition, it is preferable to use what has an internal diameter smaller than the outer diameter of an elastic belt base material as a fluororesin tube. In the case where this fluororesin tube is used, in the covering step, the fluororesin tube having an expanded diameter is coated on an elastic belt substrate, and then the expansion of the diameter is released to thereby disperse the fluororesin tube and the elastic belt. Can be brought into close contact with each other.

  In addition, from the viewpoint of obtaining good adhesion between the fluororesin tube and the elastic belt substrate, an adhesive is applied to the inner circumferential surface of the fluororesin tube and / or the outer circumferential surface of the elastic belt substrate before the coating step. It is preferable to have an adhesive coating process for coating the film. In addition, when an adhesive application process is provided, it is more preferable to have a heating process for performing heat curing of the adhesive.

Hereinafter, an example of a method for producing a fluororesin-coated belt according to the second embodiment will be described in detail with reference to the drawings.
(0) Preparation of Base Material As the base material 30 on which the elastic layer 20 is provided, a resin cylinder such as polyimide, polyamideimide, polyphenylene sulfide, polyetheretherketone, and polybenzimidazole can be used.

(1) Formation of elastic layer As a material used for the elastic layer 20, it is preferable to use silicone rubber, fluorine rubber, etc. excellent in heat resistance, and various other rubber components can be mixed and used. Moreover, various additives may be mix | blended as needed. As a method for forming the elastic layer 20 on the surface of the base material 30, a coating liquid (coating liquid for the elastic layer 20) in which the components of the elastic layer 20 are dispersed is immersed in a blade coating method or by diluting the coating liquid with a solvent. A known method such as a method of forming a coating film on the surface of the substrate 30 using a coating method or the like and then performing a heat curing process can be used. As described above, the thickness of the formed elastic layer is preferably 0.1 mm or more and 0.5 mm or less.

  As shown in FIG. 5, the obtained elastic belt substrate is inserted into the elastic belt substrate 25 tightly (that is, in a state where there is no radial play), and the 46 is supported.

(2) Preparation of fluororesin tube As the fluororesin tube, a tube molded by any method can be used, but it is obtained by extrusion from the viewpoint that a continuous long tube can be obtained. It is preferable to use those obtained.
As a material of the fluororesin tube, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA) is preferable from the viewpoint of heat resistance and the like. In addition, tetrafluoroethylene / hexafluoropropylene copolymer (FEP), polytetrafluoroethylene (PTFE), ethylene / tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene / chlorotriethylene. Various fluororesins such as fluoroethylene copolymer (ECTFE) and polyvinylidene fluoride (PVDF) can be used singly or in combination.

The thickness of the fluororesin tube is preferably 100 μm or less, and more preferably 15 μm or more.
As described above, the fluororesin tube preferably has an inner diameter smaller than the outer diameter of the elastic belt substrate, and the specific inner diameter of the fluororesin tube is 95% or more of the elastic belt substrate. 99% or less is preferable.
In addition, the width (axial length) of the fluororesin tube is preferably set longer than the width of the outer pipe 42.

  Furthermore, when the manufacturing method of the fluororesin-coated belt according to the second embodiment includes the adhesive application step, the inner peripheral surface of the fluororesin tube is subjected to chemicals such as sodium-naphthalene treatment and liquid ammonia treatment. It is preferable that the surface is modified by a general treatment or a physical treatment such as excimer laser treatment or low-temperature plasma treatment.

(3) Adhesive application process In the manufacturing method of the fluororesin-coated belt according to the second embodiment, as described above, before the coating process, the inner peripheral surface of the fluororesin tube and / or the outer periphery of the elastic belt substrate. It is preferable to have an adhesive application step of applying an adhesive to the surface.
Examples of the adhesive include silicone sealant adhesive, and specific examples include sealant 40 and sealant 45 manufactured by Shin-Etsu Silicone Co., Ltd., No. manufactured by Toray Dow Corning Silicone Co., Ltd. 051 etc. can be used conveniently. It is effective to apply the adhesive thinly by spray coating, brush coating, dip coating, or the like.
In addition, after apply | coating an adhesive agent, it is preferable to coat | cover a fluororesin tube with this adhesive agent in a semi-dry state.

(4) Covering Step First, as shown in FIG. 3, an outer pipe 42 is prepared in which the upper and lower surfaces are fully opened and a vacuuming device 44 is provided. The inner diameter of the outer pipe 42 is set to be larger than the outer diameter of the elastic belt substrate prepared above, and specifically, it is preferably 101% or more and 105% or less. The width (axial length) of the outer pipe 42 is set longer than the width of the elastic belt substrate.

  The fluororesin tube 11 is inserted into the outer pipe 42 configured as described above so that the lower end of the fluororesin tube 11 protrudes downward from the outer pipe 42. As shown in FIG. The portion projecting downward from the outer periphery of the outer pipe 42 is folded back to the outer peripheral surface of the outer pipe 42 while expanding the diameter outward in the radial direction. Further, as shown in FIG. 3, this time, while the portion of the fluororesin tube 11 protruding upward from the upper opening of the outer mold pipe 42 is expanded radially outwardly, the outer circumference of the outer mold pipe 42 is increased. Fold it over the surface.

  After correcting wrinkles / twisting of the fluororesin tube 11, as shown in FIG. 4, the vacuuming device 44 is activated to expand the diameter of the fluororesin tube 11 to the inner diameter of the outer pipe 42.

  Thereafter, as shown in FIG. 5, the fluororesin tube 11 whose diameter has been expanded is mounted on the lower lid 50 </ b> B having the convex portion 48 for alignment together with the outer pipe 42.

As shown in FIG. 5, the elastic belt substrate 25 prepared in (1) above (the elastic belt substrate 25 supported by the inner mold 46) is positioned inside the fluororesin tube for alignment. It inserts from above so that the convex part 48 may be followed.
Even when the adhesive is applied to the outer peripheral surface of the elastic belt substrate 25 and / or the inner peripheral surface of the fluororesin tube, the fluororesin tube 11 is not attached to the outer surface of the elastic belt substrate 25. Since the diameter is expanded larger than the diameter, the elastic belt substrate 25 is inserted inside the fluororesin tube 11 without any problem.

  After the elastic belt base material 25 is thus inserted inside the fluororesin tube 11, the operation of the vacuuming device 44 is stopped as shown in FIG. Thereby, the fluororesin tube 11 is contracted in the radial direction based on its own elasticity, that is, the fluororesin tube 11 is in close contact with and covered with the outer periphery of the elastic belt substrate 25. Therefore, the folded portion of the fluororesin tube folded back on the outer periphery of the outer pipe 42 is returned (in FIG. 6, the portion protruding from the upper opening is returned).

(5) Inversion step After the covering step, as shown in FIG. 7, the upper lid 50A is fitted into the upper end of the outer pipe 42, and then the entire lid is inverted as shown in FIG. The folded portion of the fluororesin tube 11 folded back on the outer periphery of the outer mold pipe 42 is restored. Further, the outer pipe 42 is removed in the direction indicated by the arrow in FIG.

(6) Heating process Moreover, when the manufacturing method of the said fluororesin coating belt has the said adhesive agent application process, it is preferable to provide the heating process which heat-hardens an adhesive agent. The heating step is preferably performed before the inner mold 46 is pulled out. In that case, it is preferable to use the inner mold 46 having heat resistance.
Although the heating temperature in the heating step varies depending on the adhesive used, it is preferable to heat at 100 ° C. or more and 200 ° C. or less, and further 120 ° C. if the adhesives listed above are used. More preferably, it is 180 ° C. or lower. The heating time is usually preferably 30 minutes or more and 180 minutes or less. In addition, as a heating means, a heating tank, a hot air dryer, etc. are mentioned.

(7) Stretching step In the method for producing a fluororesin-coated belt according to the second embodiment, the surface of the fluororesin-coated belt obtained as described above (the surface of the release layer 10) is stretched. As the stretching treatment, a method of stretching by applying droplets (for example, water or a mixed solution of water and filler) to the small area (spot) on the surface of the release layer 10 at high pressure is preferably used. For example, as shown in FIG. 9, first, the fluororesin-coated belt 70 is rotated together with the inner mold 46 in the direction of arrow K, and droplets 84 are applied to the surface of the fluororesin-coated belt 70 from the injection nozzle 82 that moves in the direction of arrow L. Inject.

  Here, the “small region (spot)” represents a region having a diameter of 50 mm or less, and the spot is more preferably 30 mm or less, and particularly preferably 10 mm or less.

  The “high pressure” is preferably 0.05 Mpa or more and 5 Mpa or less, and more preferably 0.1 Mpa or more and 1 Mpa or less.

  Examples of the droplet 84 applied to the surface of the release layer 10 include water and a mixed liquid of water and a filler as described above. Examples of the filler include aluminum oxide, cerium oxide, melamine resin particles, urea resin particles, other resin particles, and glass beads. Among these, aluminum oxide and cerium oxide are particularly preferably used.

  In addition, when the surface of the release layer 10 is cloudy (that is, when the surface is worn by the filler) when droplets are applied to the surface of the release layer 10, vinyl is applied to the surface of the release layer 10. A protective film 86 such as a film or a plastic bag may be disposed, and the stretching process may be performed through the protective film 86.

(8) Drawing and finishing process Thereafter, the inner mold 46 is drawn from the inside of the elastic belt substrate 25 to obtain a fluororesin-coated belt. As shown in FIG. 10, the inner mold 46 may be pulled out while squeezing with a flaky blade 52 made of a material such as silicone rubber or fluorine resin. By pulling out while squeezing with the blade 52, it is possible to remove minute bubbles remaining between the elastic layer and the tube that do not cause a problem in use.

  Further, as a step of finishing the obtained fluororesin-coated belt, a step of cutting off the excess fluororesin tube 11 can be provided after the inner mold 46 is pulled out. The finishing step is preferably performed after the heating step.

As described above, a fluororesin-coated belt can be obtained. In addition, in the manufacturing method of the fluororesin coating belt which concerns on 2nd Embodiment, it cannot be overemphasized that it can change variously in the range which does not deviate from a summary, without being limited to the procedure mentioned above.
For example, as a method of covering the elastic belt substrate 25 with the fluororesin tube 11, the fluororesin tube 11 may be expanded and then covered with the elastic belt substrate 25. Alternatively, it is possible to expand the coating stepwise before coating and during coating.

<Fixing device and image forming apparatus>
Next, an image forming apparatus according to a third embodiment in which the fluororesin-coated belt according to the first embodiment is used as a fixing belt in the image fixing apparatus will be described in detail.
FIG. 11 is a schematic configuration diagram illustrating an image forming apparatus to which the third embodiment is applied. The image forming apparatus shown in FIG. 11 is an intermediate transfer type image forming apparatus generally called a tandem type, and a plurality of image forming units 1Y, 1M, 1C, and 1K in which toner images of respective color components are formed by electrophotography. The primary transfer unit 110 that sequentially transfers (primary transfer) the color component toner images formed by the image forming units 1Y, 1M, 1C, and 1K to the intermediate transfer belt 115, and the superimposed toner image transferred onto the intermediate transfer belt 115. Are provided with a secondary transfer section 120 that collectively transfers (secondary transfer) to a paper P that is a recording material (recording paper), and an image fixing device 160 that fixes the secondary transferred image onto the paper P. Moreover, it has the control part 140 which controls operation | movement of each apparatus (each part).

  In the third embodiment, each of the image forming units 1Y, 1M, 1C, and 1K includes a charger 112 that charges the photosensitive drum 111 around the photosensitive drum 111 that rotates in the direction of arrow A, and a photosensitive drum. A laser exposure unit 113 for writing an electrostatic latent image on 111 (exposure beam is indicated by Bm in the figure), each color component toner is accommodated, and the electrostatic latent image on the photosensitive drum 111 is visualized with toner. Developing unit 114, primary transfer roll 116 for transferring each color component toner image formed on photosensitive drum 111 to intermediate transfer belt 115 by primary transfer unit 110, and drum from which residual toner on photosensitive drum 111 is removed. Electrophotographic devices such as a cleaner 117 are sequentially disposed. These image forming units 1Y, 1M, 1C, and 1K are linearly arranged in the order of yellow (Y), magenta (M), cyan (C), and black (K) from the upstream side of the intermediate transfer belt 115. ing.

The intermediate transfer belt 115 that is an intermediate transfer member is constituted by a film-like endless belt in which an appropriate amount of an antistatic agent such as carbon black is contained in a resin such as polyimide or polyamide. The volume resistivity is 10 ⁶ Ωcm or more and 10 ¹⁴ Ωcm or less, and the thickness is, for example, about 0.1 mm. The intermediate transfer belt 115 is circulated and driven at a predetermined speed in the direction B shown in FIG. 11 by various rolls. As these various rolls, a drive roll 131 that is driven by a motor (not shown) having excellent constant speed to drive the intermediate transfer belt 115, and an intermediate transfer that extends linearly along the arrangement direction of the photosensitive drums 111. A support roll 132 that supports the belt 115, a tension roll 133 that functions as a correction roll that applies a constant tension to the intermediate transfer belt 115 and prevents meandering of the intermediate transfer belt 115, and a backup roll provided in the secondary transfer unit 120 125, a cleaning backup roll 134 provided in a cleaning unit that scrapes residual toner on the intermediate transfer belt 115 is disposed.

The primary transfer unit 110 includes a primary transfer roll 116 that is disposed to face the photosensitive drum 111 with the intermediate transfer belt 115 interposed therebetween. The primary transfer roll 116 is composed of a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM blended with a conductive agent such as carbon black and having a volume resistivity of 10 ⁷ Ωcm to 10 ⁹ Ωcm. The primary transfer roll 116 is disposed in pressure contact with the photosensitive drum 111 with the intermediate transfer belt 115 interposed therebetween. Further, the primary transfer roll 116 has a voltage with a polarity opposite to that of the toner charging polarity (negative polarity, hereinafter the same). (Primary transfer bias) is applied. As a result, the toner images on the respective photosensitive drums 111 are sequentially electrostatically attracted to the intermediate transfer belt 115, and the toner images superimposed on the intermediate transfer belt 115 are formed.

The secondary transfer unit 120 includes a secondary transfer roll 122 disposed on the toner image holding surface side of the intermediate transfer belt 115 and a backup roll 125. The backup roll 125 is composed of a EPDM and NBR blend rubber tube with carbon dispersed on the surface and an EPDM rubber inside. The surface resistivity is 10 ⁷ Ω / □ or more and 10 ¹⁰ Ω / □ or less, and the hardness is set to 70 ° (Asker C), for example. The backup roll 125 is disposed on the back side of the intermediate transfer belt 115 to form a counter electrode of the secondary transfer roll 122, and a metal power supply roll 126 to which a secondary transfer bias is stably applied is disposed in contact. Yes.

On the other hand, the secondary transfer roll 122 is composed of a shaft and a sponge layer as an elastic layer fixed around the shaft. The shaft is a cylindrical bar made of metal such as iron or SUS. The sponge layer is a sponge-like cylindrical roll formed of a blend rubber of NBR, SBR, and EPDM blended with a conductive agent such as carbon black and having a volume resistivity of 10 ⁷ Ωcm to 10 ⁹ Ωcm. The secondary transfer roll 122 is disposed in pressure contact with the backup roll 125 with the intermediate transfer belt 115 interposed therebetween. Further, the secondary transfer roll 122 is grounded and a secondary transfer bias is formed in a region sandwiched between the backup roll 125, The toner image is secondarily transferred onto the paper P conveyed to the secondary transfer unit 120.

  Further, on the downstream side of the secondary transfer portion 120 of the intermediate transfer belt 115, an intermediate transfer belt that removes residual toner and paper dust on the intermediate transfer belt 115 after the secondary transfer and cleans the surface of the intermediate transfer belt 115. A cleaner 135 is detachably provided. On the other hand, on the upstream side of the yellow image forming unit 1Y, a reference sensor (home position sensor) 142 that generates a reference signal serving as a reference for taking image forming timings in the image forming units 1Y, 1M, 1C, and 1K. It is arranged. Further, an image density sensor 143 for adjusting image quality is disposed on the downstream side of the black image forming unit 1K. The reference sensor 142 recognizes a predetermined mark provided on the back side of the intermediate transfer belt 115 and generates a reference signal. Each image forming unit is instructed by an instruction from the control unit 140 based on the recognition of the reference signal. 1Y, 1M, 1C, and 1K are configured to start image formation.

  Furthermore, in the image forming apparatus according to the third embodiment, as a paper transport system, a paper supply unit 150 that stores paper P, and a pickup roll that picks up and transports the paper P accumulated in the paper supply unit 150 at a predetermined timing. 151, a transfer roll 152 that transports the paper P fed by the pickup roll 151, a transport member 153 that feeds the paper P transported by the transport roll 152 to the secondary transfer unit 120, and a secondary transfer roll 122. A conveyance belt 155 that conveys the sheet P conveyed to the image fixing apparatus 160 and a fixing entrance guide 156 that guides the sheet P to the image fixing apparatus 160 are provided.

  Next, a basic image forming process of the image forming apparatus according to the third embodiment will be described. In the image forming apparatus shown in FIG. 11, image data output from an image reading device (not shown) or a personal computer (PC) (not shown) is subjected to predetermined image processing by an image processing device (not shown), and then an image forming unit. Image forming work is executed by 1Y, 1M, 1C, and 1K. The image processing apparatus performs predetermined image processing such as shading correction, position shift correction, brightness / color space conversion, gamma correction, frame deletion, color editing, moving editing, and other various image editing on the input reflectance data. Is given. The image data that has been subjected to image processing is converted into color material gradation data of four colors Y, M, C, and K, and is output to the laser exposure unit 113.

  The laser exposure unit 113 irradiates the photosensitive drums 111 of the image forming units 1Y, 1M, 1C, and 1K, for example, with an exposure beam Bm emitted from a semiconductor laser in accordance with the input color material gradation data. Yes. In each of the photosensitive drums 111 of the image forming units 1Y, 1M, 1C, and 1K, after the surface is charged by the charger 112, the surface is scanned and exposed by the laser exposure unit 113 to form an electrostatic latent image. The formed electrostatic latent images are developed as toner images of respective colors Y, M, C, and K by the developing devices 114 of the respective image forming units 1Y, 1M, 1C, and 1K.

  The toner images formed on the photosensitive drums 111 of the image forming units 1Y, 1M, 1C, and 1K are transferred onto the intermediate transfer belt 115 in the primary transfer unit 110 where the photosensitive drums 111 and the intermediate transfer belt 115 are in contact with each other. Transcribed. More specifically, in the primary transfer unit 110, a voltage (primary transfer bias) having a polarity opposite to the toner charging polarity (plus polarity) is applied to the base material of the intermediate transfer belt 115 by the primary transfer roll 116, and the toner image. Are sequentially superimposed on the surface of the intermediate transfer belt 115 to perform primary transfer.

  After the toner images are sequentially primary transferred onto the surface of the intermediate transfer belt 115, the intermediate transfer belt 115 moves and the toner image is conveyed to the secondary transfer unit 120. When the toner image is conveyed to the secondary transfer unit 120, in the paper conveyance system, the pickup roll 151 rotates in accordance with the timing at which the toner image is conveyed to the secondary transfer unit 120, and a predetermined size is supplied from the paper supply unit 150. Paper P is supplied. The paper P supplied by the pickup roll 151 is transported by the transport roll 152, and reaches the secondary transfer unit 120 through the transport member 153. Before reaching the secondary transfer unit 120, the paper P is temporarily stopped, and the registration roller (not shown) rotates in accordance with the movement timing of the intermediate transfer belt 115 on which the toner image is held. And the position of the toner image are aligned.

  In the secondary transfer unit 120, the secondary transfer roll 122 is pressed against the backup roll 125 via the intermediate transfer belt 115. At this time, the sheet P conveyed at the same timing is sandwiched between the intermediate transfer belt 115 and the secondary transfer roll 122. At this time, when a voltage (secondary transfer bias) having the same polarity (negative polarity) as the toner charging polarity is applied from the power supply roll 126, a transfer electric field is generated in a region sandwiched between the secondary transfer roll 122 and the backup roll 125. Is formed. The unfixed toner image held on the intermediate transfer belt 115 is collectively electrostatically transferred onto the paper P in the secondary transfer unit 120 pressed by the secondary transfer roll 122 and the backup roll 125. .

Thereafter, the sheet P on which the toner image has been electrostatically transferred is transported as it is while being peeled off from the intermediate transfer belt 115 by the secondary transfer roll 122, and transported downstream of the secondary transfer roll 122 in the sheet transport direction. It is conveyed to the belt 155. The transport belt 155 transports the paper P to the image fixing device 160 at an optimal transport speed in accordance with the transport speed in the image fixing device 160. The unfixed toner image on the paper P conveyed to the image fixing device 160 is fixed on the paper P by being subjected to fixing processing by heat and pressure by the image fixing device 160. The paper P on which the fixed image is formed is conveyed to a paper discharge unit (not shown) provided in the discharge unit of the image forming apparatus.
On the other hand, after the transfer to the paper P is completed, the residual toner remaining on the intermediate transfer belt 115 is conveyed as the intermediate transfer belt 115 is driven, and the intermediate transfer belt is cleaned by the cleaning backup roll 134 and the intermediate transfer belt cleaner 135. 115 is removed from above.

Next, an image fixing device 160 used in the image forming apparatus of the third embodiment will be described.
FIG. 12 is a side sectional view showing a schematic configuration of an image fixing device 160 according to the third embodiment. The main part of the image fixing device 160 includes a fixing belt module 161 as an example of a heating member and a pressure roll 162 as an example of a pressure member disposed in pressure contact with the fixing belt module 161. ing.
The fixing belt module 161 includes a fixing belt 610 as an example of a belt member, a fixing roll 611 that rotates while the fixing belt 610 is stretched, a tension roll 612 that stretches the fixing belt 610 from the inside, and a fixing belt 610 from the outside. The main part is composed of a tension roll 613 that stretches the belt, and a posture correction roll 614 that corrects the posture of the fixing belt 610 in a region sandwiched between the fixing roll 611 and the tension roll 612.

  The fixing belt 610 is a flexible endless belt having a circumferential length of 314 mm and a width of 340 mm, and has a thickness laminated on a base material made of polyimide resin having a thickness of 80 μm and on the surface side (outer peripheral surface side) of the base material. An elastic layer made of 200 μm silicone rubber, and a release layer formed of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) tube having a thickness of 30 μm as a release layer on the elastic layer. The fluororesin-coated belt according to the first embodiment described above, which has a multilayer structure, is used.

The fixing roll 611 is a cylindrical roll formed of aluminum having an outer diameter of 65 mm, a length of 360 mm, and a thickness of 10 mm. The fixing roll 611 receives a driving force from a driving motor (not shown) and rotates in the arrow C direction at a surface speed of 300 mm / s.
In addition, a halogen heater 616a rated at 900 W is provided as a heating source inside the fixing roll 611, and based on the measured value of the temperature sensor 617a arranged so as to be in contact with the surface of the fixing roll 611, The controller 40 (see FIG. 11) controls the surface temperature of the fixing roll 611 to 150 ° C.

The tension roll 612 is a cylindrical roll formed of aluminum having an outer diameter of 30 mm, a wall thickness of 2 mm, and a length of 360 mm. A halogen heater 616b rated at 1000 W is disposed as a heating source inside the tension roll 612, and the surface temperature of the tension roll 612 is 190 by the temperature sensor 617b and the control unit 40 (see FIG. 11). It is controlled at ℃. Therefore, the stretching roll 612 has a function of heating the fixing belt 610 as well as a function of stretching the fixing belt 610.
In addition, spring members (not shown) that press the fixing belt 610 outward are disposed at both ends of the tension roll 612, and the tension of the entire fixing belt 610 is set to 15 kgf. At that time, in order to make the tension of the fixing belt 610 uniform in the width direction and to suppress the displacement of the fixing belt 610 in the axial direction as much as possible, the tension roll 612 has an outer diameter at the center portion rather than the end portion. It is formed in a so-called crown shape that is larger by 100 μm.

The tension roll 613 is a cylindrical roll formed of aluminum having an outer diameter of 25 mm, a thickness of 2 mm, and a length of 360 mm. Further, the surface of the stretching roll 613 is coated with 20 μm thick PFA to form a release layer. This release layer is formed to prevent offset toner and paper powder from the outer peripheral surface of the fixing belt 610 from accumulating on the stretching roll 613. Further, the tension roll 613 is formed in a crown shape in which the outer diameter is larger by 100 μm at the center than at the end, like the tension roll 612. Note that not only the tension roll 612 and the tension roll 613 are both formed in a crown shape, but only one of the tension roll 612 and the tension roll 613 may be formed in a crown shape.
Inside the tension roll 613, a halogen heater 616c rated as 1000 W as a heating source is disposed, and the surface temperature is controlled to 190 ° C. by the temperature sensor 617c and the control unit 40 (see FIG. 11). . Accordingly, the tension roll 613 has a function of stretching the fixing belt 610 and a function of heating the fixing belt 610 from the outer surface. Therefore, in the third embodiment, a configuration in which the fixing belt 610 is heated by the fixing roll 611, the stretching roll 612, and the stretching roll 613 is employed.

  The posture correction roll 614 is a cylindrical roll formed of aluminum having an outer diameter of 15 mm and a length of 360 mm. A belt edge position detection mechanism (not shown) that detects the edge position of the fixing belt 610 is disposed in the vicinity of the posture correction roll 614. The posture correction roll 614 is provided with an axis displacement mechanism that displaces the contact position in the axial direction of the fixing belt 610 according to the detection result of the belt edge position detection mechanism, and controls meandering (belt walk) of the fixing belt 610. Is configured to do.

  Next, the pressure roll 162 has a cylindrical roll 621 made of aluminum having a diameter of 45 mm and a length of 360 mm as a base, and in order from the base side, a 10 mm thick made of silicone rubber having a rubber hardness of 30 ° (JIS-A). An elastic layer 622 and a release layer 623 made of a PFA tube having a film thickness of 100 μm are laminated. The pressure roll 162 is installed so as to be pressed against the fixing belt module 161. As the fixing roll 611 of the fixing belt module 161 rotates in the direction of arrow C, the pressure roll 162 follows the fixing roll 611 and moves in the direction of arrow E. To drive. The traveling speed is 300 mm / s, which is the same as the surface speed of the fixing roll 611.

Next, the pressing portion N where the fixing belt module 161 and the pressure roll 162 are pressed against each other will be described.
The pressure roller 162 is fixed to the pressing portion N where the fixing belt module 161 and the pressure roller 162 are pressed against each other in a region (wrap region) where the fixing belt 610 is wound (wrapped) around the fixing roller 611. The roll pressing portion N is formed by being disposed so as to be in pressure contact with the outer peripheral surface of the belt 610.

Here, in the image fixing device 160 of the third embodiment, as described above, the fixing roll 611 is configured by a hard roll formed of aluminum, and the pressure roll 162 is configured by a soft roll covered with an elastic layer 622. Has been.
In the image fixing device 160 of the third embodiment, the roll pressing portion N is set to a width of 15 mm along the traveling direction of the fixing belt 610.

Next, a fixing operation in the image fixing device 160 of the third embodiment will be described.
The sheet P on which the unfixed toner image is electrostatically transferred in the secondary transfer section 120 (see FIG. 11) of the image forming apparatus is directed toward the pressing section N of the image fixing apparatus 160 by the conveyance belt 155 and the fixing inlet guide 156. (See FIG. 12: arrow F direction) The unfixed toner image on the surface of the paper P passing through the pressing portion N is fixed on the paper P by the pressure and heat acting on the roll pressing portion N.

  At this time, in the image fixing device 160 of the third embodiment, heat acting on the pressing portion N is mainly supplied by the fixing belt 610. The fixing belt 610 is supplied through the tension roll 612 from the heat supplied from the halogen heater 616a disposed inside the fixing roll 611 through the fixing roll 611 and from the halogen heater 616b disposed inside the tension roll 612. It is configured to be heated by heat and heat supplied through the tension roll 613 from the halogen heater 616 c disposed inside the tension roll 613.

  The paper P separated from the fixing belt 610 is discharged out of the apparatus by the paper discharge guide 165 and the paper discharge roll 166, and the fixing process is completed.

  Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. However, it is not limited to these.

<Comparative Example 1>
First, a polyimide belt having a thickness of 80 μm and an outer diameter of 168 mm was prepared as a base material. Next, Si rubber (manufactured by Toray Dow Corning: CF9379) is diluted to 85% by mass with a solvent (butyl acetate) on the base material, and a dry film thickness of 0.15 mm is obtained by blade coating. Coated and heat-cured to form an elastic layer

  Next, a PFA tube having a thickness of 20 μm and an inner diameter of 165 mm was formed by an extrusion molding method, and an adhesive (manufactured by Dow Corning Toray: 015) was spray applied onto the inner surface thereof. Based on the method described in the second embodiment, a PFA tube is coated on a base material on which an elastic layer is formed to form a release layer, and a fluororesin-coated belt (1A) according to Comparative Example 1 is obtained. It was.

-Measurement of dynamic micro hardness-
The dynamic micro hardness of the fluororesin-coated belt (1A) was measured by the method described above. The results are shown in Table 1.

-Warping back test-
2A, a 50 mm × 25 mm rectangular test piece (thickness equal to the thickness of the fluororesin-coated belt) 72 having a long side in the circumferential direction is cut out from the fluororesin-coated belt (1A). The test piece 72 was placed on the flat plate 74 with the outer peripheral surface side up, and it was observed whether the state of warping / returning at that time corresponds to any of the following (b) to (d). The results are shown in Table 1.
(B) Warps to the belt outer peripheral surface side (state shown in FIG. 2 (B))
(C) No warpage (state shown in FIG. 2C)
(D) Warps to the belt inner peripheral surface side (state shown in FIG. 2D)

-Evaluation of pear texture-
The above fluororesin-coated belt (1A) is replaced with an image forming apparatus shown in FIG. 11 (an image forming apparatus in which a fixing device of Fuji Xerox Co., Ltd., product name: Color DocuTech 60 is modified to a fixing apparatus shown in FIG. It was mounted as a fixing belt of an image fixing apparatus at a conveyance speed of 250 mm / second) and image output evaluation was performed. Evaluation was made by visual observation and was performed according to the following criteria. Grade 1 or 2 is a usable level.
1: No satin image quality 2: The satin image quality is slightly recognized in the oblique gloss image.
3: The satin image quality is confirmed in the oblique gloss image.
4: The satin image quality is confirmed in the front view.
5: The satin image quality is remarkably confirmed in the front view.

<Comparative Examples 2-4>
The fluororesin-coated belts according to Comparative Examples 2, 3 and 4 were prepared by the method described in Comparative Example 1 except that the thicknesses of the base material, the elastic layer and the release layer were changed as shown in Table 1 below. 1B), (1C) and (1D) were obtained, and various measurements and evaluation of satin image quality were performed.

<Examples 1-4>
The fluororesin-coated belts (1A), (1B), (1C) and (1D) produced in Comparative Examples 1 to 4 are subjected to the stretching treatment shown below, and the fluororesin-coated belts according to Examples 1 to 4 (2A), (2B), (2C) and (2D) were obtained, and various measurements and evaluation of satin image quality were performed.

[Stretching treatment]
As a stretching apparatus, a product name manufactured by Fuji Seiki Seisakusho: liquid honing apparatus Model: L5-12-S was used, and a mixed liquid of aluminum oxide and water was prepared as droplets. The pressure and spot diameter were set as shown in Table 2 below, and the drawing process was performed by applying droplets to the surface of the release layer.

It is a model perspective view which shows the one aspect | mode of the fluororesin coating belt which concerns on 1st Embodiment. (A) is a schematic diagram showing cutout of a test piece in a warp-back test, and (B), (C) and (D) are schematic diagrams showing a state of warp-back when the test piece is arranged on a plane. is there. In the manufacturing method of the fluororesin covering belt concerning a 2nd embodiment, it is a mimetic sectional view showing the state where a fluororesin tube was inserted in an external pipe. It is a schematic cross section which shows the state which expanded the diameter of the fluororesin tube in the manufacturing method of the fluororesin coating belt which concerns on 2nd Embodiment. It is a schematic cross section which shows the state which inserts an elastic belt base material in a fluororesin tube in the manufacturing method of the fluororesin coating belt which concerns on 2nd Embodiment. In the manufacturing method of the fluororesin covering belt concerning a 2nd embodiment, it is a schematic sectional view which shows the state where the expansion of the diameter of a fluororesin tube was released and it made it stick to an elastic belt substrate. It is a schematic cross section which shows the state which installed the upper cover in the manufacturing method of the fluororesin coating belt which concerns on 2nd Embodiment. In the manufacturing method of the fluororesin covering belt concerning a 2nd embodiment, it is a typical sectional view showing the state where the whole was reversed and a lower lid and an outside type pipe were removed. It is the schematic showing the processing method of an extending | stretching process. In the manufacturing method of the fluororesin coating belt which concerns on 2nd Embodiment, it is a schematic cross section which shows the state which pulls out an inner type | mold while ironing with a blade. FIG. 10 is a schematic cross-sectional view illustrating a configuration example of an image forming apparatus according to a third embodiment. FIG. 12 is an enlarged schematic cross-sectional view of the image fixing device shown in FIG. 11.

Explanation of symbols

1Y, 1M, 1C, 1K Image forming unit 10 Release layer 11 Fluororesin tube 20 Elastic layer 25 Elastic belt base material 30 Base material 42 External mold pipe 44 Vacuum drawing device 46 Inner mold 48 Protruding part 50A Upper cover 50B Lower cover 52 Blade 70 Fluoropolymer coated belt 72 Test piece 74 Flat plate 82 Injection nozzle 84 Droplet 86 Protective film 115 Intermediate transfer belt 160 Fixing device 161 Fixing belt module 162 Pressure roll 610 Fixing belt 611 Fixing rolls 612 and 613 Stretching rolls 616a and 616b 616c Halogen heater

Claims (7)

A base material, an elastic layer, and a release layer made of a fluororesin annular body are provided in this order,
A fluororesin-coated belt characterized in that the dynamic microhardness of the surface on the side where the release layer is formed is 1.00 or less.   The fluororesin-coated belt according to claim 1, wherein the dynamic micro hardness is 0.5 or less. A rectangular test piece of 50 mm × 25 mm having a long side in the circumferential direction is cut out, and the state of warping when the test piece is arranged on a plane is the following (c) or (d): The fluororesin-coated belt according to claim 1 or 2.
(C) No warping / returning (d) Warping to the belt inner surface side   The fluororesin-coated belt according to any one of claims 1 to 3, wherein the elastic layer has a thickness of 0.1 mm to 0.5 mm. An elastic layer forming step of forming an elastic layer on the substrate;
A fluororesin coating step of forming a release layer by coating a fluororesin annular body on the elastic layer;
And a stretching step of stretching the release layer. A method for producing a fluororesin-coated belt. The fluororesin-coated belt according to any one of claims 1 to 4,
An image fixing apparatus comprising: a pressure rotating body disposed to face the fluororesin-coated belt.   An image holding member, a toner image forming unit that forms a toner image on the surface of the image holding member, a transfer unit that transfers the toner image to a recording medium, and an image fixing device according to claim 6. An image forming apparatus comprising: fixing means for fixing the toner image to a recording medium.

Images