JP5926473B2 - Fixing belt - Google Patents

Description

  The present invention relates to a fixing belt used for heating and fixing a toner image transferred onto a transfer material such as recording paper in an image forming apparatus such as an electrophotographic copying machine, a facsimile machine, a laser beam printer, and the like. More particularly, the present invention relates to a fixing belt used for fixing a toner image by heating in an image forming apparatus using a plurality of types of color toners.

  In an image forming apparatus such as an electrophotographic copying machine, a facsimile, or a laser beam printer, at the final stage of printing or copying, a fixing belt (ie, a fixing sleeve or a fixing tube roller) provided with a heating source and pressurization are provided. In general, a thermal fixing method is used in which a roller is pressed into contact with a transfer object on which a toner image is transferred, and unfixed toner is heated and melted.

  The fixing belt used here is excellent in elasticity, releasability, wear resistance, etc. on the surface of a cylindrical substrate made of a high-strength heat-resistant resin such as polyimide (the surface in contact with the transfer object). A fixing belt with a resin layer structure, or a fixing roller with a metal or polyimide cylinder as the base material and a resin layer with excellent elasticity, releasability, wear resistance, etc. attached to the outer periphery. It is used for. A fluororesin coating layer is widely used as a resin layer having excellent elasticity, releasability, wear resistance, and the like.

  In order to improve the fixability, it is necessary that the transfer object is sufficiently heated by a heating source provided inside. Therefore, excellent heat conductivity is required for the fixing belt.

  Furthermore, in fixing an image forming apparatus using a plurality of types of color toners, it is necessary to mix a plurality of types of color toners in a molten state at the time of fixing. Therefore, a fixing belt for this purpose is required to have an appropriate elasticity that can sufficiently wrap and melt and mix color toner.

  As described above, the fixing belt is required to have excellent thermal conductivity and appropriate elasticity. In order to satisfy this requirement, in Patent Document 1, a heat-resistant elastomer layer (elasticity) is formed on the outer peripheral side of the tubular substrate. Layer), and further a fluororesin layer thereon, the thickness of the tubular substrate, the fluororesin layer and the heat-resistant elastomer layer is defined, and the thickness and hardness of the heat-resistant elastomer And a fixing belt (Claim 2) in which the relationship between the thermal conductivity and the thermal conductivity is defined within a predetermined range has been proposed. And in order to satisfy | fill this condition, the technique of mix | blending the inorganic filler which improves heat conductivity, such as a silica, an alumina, a boron nitride, etc. with a heat resistant elastomer is proposed (paragraph 0015).

  Patent Document 2 discloses a fixing belt having a laminated structure in which a heat-resistant elastomer layer is formed on the outer surface of a metal tube or a heat-resistant plastic tube, and a layer of silicone rubber or fluororesin is further formed on the outer surface. A fixing belt is disclosed in which the amount of strain with respect to the load, the thickness of each layer, and the like are within a predetermined range, and the hardness and thermal conductivity of the heat-resistant elastomer layer are also within a predetermined range.

  And in order to make the heat conductivity of the heat resistant elastomer layer within a predetermined range, a method of blending an inorganic filler for improving the heat conductivity such as silica, alumina, boron nitride, etc. has been proposed. It is disclosed that heat from a heating source can be rapidly supplied to the outer surface of the fixing belt (paragraph 0012).

Japanese Patent No. 3735991 Japanese Patent No. 3712086

  However, in recent years, with the increase in printing speed, a higher thermal conductivity tends to be required for the fixing belt. Therefore, in order to achieve fixing properties that meet the strict requirements of users in recent years, the above-described prior art has become insufficient in thermal conductivity, and improvement in thermal conductivity has been desired.

  In order to obtain a higher thermal conductivity, a method of increasing the amount of a filler (inorganic filler or the like) that improves thermal conductivity can be considered. However, in the fixing belt described in Patent Documents 1 and 2, when the amount of inorganic filler such as silica, alumina, boron nitride or the like is increased, the elasticity of the fixing belt is lowered and the color toner is sufficiently wrapped and melted. -It becomes difficult to obtain an appropriate elasticity that can be mixed.

Carbon nanotubes (hereinafter sometimes abbreviated as “CNT”), which are nano-sized cylindrical carbons, are known as materials that are blended with resins and the like to improve thermal conductivity. CNTs have a true specific gravity of 2.0 g / cm ³ and an aspect ratio of usually 50 to 1000. Graphite-structured CNTs are preferably used at such a high aspect ratio. As the CNT, a single-layer type and a multi-layer type having a concentric inner structure are typical.

  The CNT includes, for example, carbon nanofibers having a fiber diameter of 1 μm or less, and CNTs in which cup-shaped carbon materials with empty bottoms are overlapped. Japanese Patent Application Laid-Open No. 2004-123867 discloses a polyimide tube in which CNT is blended. However, since CNT is blended in a polyimide resin, the mechanical strength is remarkably lowered when the blending ratio is increased.

  The present invention has a high thermal conductivity corresponding to the recent increase in printing speed, and has an appropriate elasticity that can sufficiently wrap and melt and mix color toners, and has high mechanical strength. It is an object of the present invention to provide an excellent fixing belt.

  As a result of intensive studies, the present inventor has found that a tube-shaped base material, a surface layer, and a fixing belt having an elastic layer between the base material and the surface layer, a rubber containing a filler and a carbon nanotube as a material of the elastic layer , By finding the blending ratio of the filler and carbon nanotubes within the range represented by the predetermined formula, it can be found that both high thermal conductivity and appropriate elasticity can be achieved, and the mechanical strength does not decrease, The present invention has been completed. That is, the above problem is solved by the invention having the following configuration.

The invention according to claim 1 is a fixing belt having a tubular base material, an elastic layer provided on the outer peripheral side of the base material, and a surface layer provided on the outer peripheral side surface of the elastic layer,
The elastic layer is formed by blending rubber with a filler and carbon nanotubes,
In the elastic layer, when the total volume of the elastic layer is 100%, the true volume ratio (%) of the filler is X, and the true volume ratio (%) of the carbon nanotube is Y , 10X + 3Y < 750, 3X + 30Y> 170, and Y> 0.1.

  As described above, in the fixing belt, in order to achieve excellent thermal conductivity satisfying recent requirements, it is necessary to increase the blending ratio of the filler such as silica, alumina, boron nitride and the like into the elastic layer. In such a case, the elastic layer becomes hard and sufficient elasticity cannot be obtained to sufficiently enclose the color toner and melt and mix the color toner. However, if carbon nanotubes are used in combination with these fillers, or carbon nanotubes are used alone instead of these fillers, and their blending amount is within the range represented by the above formula, the recent demand has been increased. Both excellent thermal conductivity and adequate elasticity can be achieved.

  The present invention is characterized in that 10X + 3Y <750, where X is the volume% of the filler in the elastic layer and Y is the volume% of the carbon nanotube. When 10X + 3Y is 750 or more, the elastic layer becomes hard and it becomes difficult to obtain an appropriate elasticity enough to wrap the color toner and melt and mix it (the value of 10X + 3Y is highly correlated with the hardness of the elastic layer) Therefore, hereinafter, the value of 10X + 3Y may be referred to as a hardness index.) 10X + 3Y is preferably less than 650, more preferably less than 600, and more excellent fixability can be obtained.

  X and Y mean the ratio (%) of the true volume of the filler and the carbon nanotube when the total volume of the elastic layer is 100%. The true volume can be easily calculated from the respective weight and specific gravity.

  The present invention is also characterized in that 3X + 30Y> 170. When 3X + 30Y is 170 or less, excellent fixability cannot be obtained (the value of 3X + 30Y is highly correlated with the thermal conductivity of the elastic layer. Therefore, the value of 3X + 30Y is hereinafter sometimes referred to as a thermal conductivity index. ). 3X + 30Y is preferably 180 or more, and more preferably 200 or more, and more excellent fixability can be obtained.

  In the present invention, the carbon nanotube is contained in the elastic layer so that Y> 0.1. When carbon nanotubes are not included, for example, when Y = 0, it is necessary to increase the blending ratio of fillers such as silica, alumina, boron nitride, and graphite, and as a result, appropriate elasticity cannot be obtained. By setting the content ratio of carbon nanotubes in a range where Y> 0.1, the blending ratio of fillers such as silica, alumina, boron nitride, and graphite can be reduced, and as a result, more appropriate elasticity. Can be achieved.

  On the other hand, the upper limit of Y is preferably 40 or less, more preferably 20 or less. If the amount of carbon nanotubes is too large, the viscosity of the coating solution used for forming the elastic layer may become too high, which may cause a coating problem. However, if the amount is within the above range, this problem may also occur. In addition, the mechanical strength of the fixing belt does not decrease.

  As described above, the carbon nanotubes used in the present invention are made of carbon crystals (graphite or the like), have a short axis diameter (fiber diameter) of submicron size or less, and the graphite layer is cylindrical. The carbon fiber (CF) etc. below submicron size are also included.

  The invention according to claim 2 is the fixing belt according to claim 1, wherein the filler is mainly composed of metal silicon powder. Here, “mainly” means that the metal silicon powder is contained in 50% by volume or more in the total amount of the filler.

  As the filler used in the present invention, a filler which is blended as a filler for improving the thermal conductivity in the conventional fixing belt, for example, one selected from alumina, silica, boron nitride and graphite is used. be able to. However, the present inventor shows that when metal silicon powder is used as the filler, the adhesion between the substrate / primer layer / elastic layer is particularly excellent, and the occurrence of peeling during use of the printer (copy machine) can be prevented. I found it. As a metal silicon powder, what is marketed by brand names, such as M-Si # 600 (The Kinsei Matec Co., Ltd. make, crush shape, average particle diameter of about 6.0 micrometers), can also be used, for example.

  As a material (matrix material) constituting the elastic layer, a heat-resistant elastomer used for an intermediate layer for imparting elasticity in a conventional fixing belt can be used. The rubber is not necessarily limited to vulcanized rubber, and it is possible to use a rubber that is not easily deteriorated by heating during manufacture and use of the fixing belt and has elasticity. As the heat resistant elastomer, silicone rubber or fluoro rubber is preferably used since it has excellent heat resistance.

  As the material of the surface layer, a fluororesin having excellent toner releasability and excellent durability and color toner fixability is preferably used.

  Examples of the tube-shaped (tubular) base material include a tube-shaped base material and a cylindrical base material made of a flexible material. Therefore, the fixing belt (fixing sleeve) of the present invention has a structure in which a tube-shaped base material made of a flexible material, an elastic layer provided on the outer peripheral side thereof, and a surface layer formed on the outer peripheral side of the elastic layer. Examples thereof include a fixing belt, a cylindrical substrate, an elastic layer provided on the outer peripheral side thereof, and a fixing roller having a structure in which a surface layer is formed on the outer peripheral side of the elastic layer.

  Specifically, the tube-shaped base material may be a metal tube or a heat-resistant plastic tube (Claim 5), but the tube-shaped base material made of a flexible material may be polyimide or A cylindrical film (tube) made of polyamideimide is preferably used because it has excellent heat resistance and mechanical strength (Claim 6). In order to improve the thermal conductivity of the equipment, an inorganic filler or the like may be added as long as the mechanical strength allows. A metal tube etc. can also be used as a cylindrical base material.

  In the fixing belt (fixing sleeve) of the present invention, if the adhesion between the layers is insufficient, the layers may be peeled off during use of the printer (copier). Therefore, usually, a lower primer layer (referred to as a primer layer provided between the base material and the elastic layer) is provided between the base material and the elastic layer, and an upper primer layer is provided between the elastic layer and the surface layer in order to improve adhesion between the layers. (Refers to a primer layer provided between the elastic layer and the surface layer).

  However, even when the lower primer layer is provided, depending on the type of filler and its blending amount, such as when the filler is other than metal silicon powder, the adhesion between the substrate / lower primer layer / elastic layer is not sufficient, The elastic layer may be easily peeled off from the substrate during use of the printer (copier). As a result of studies to solve this problem, the present inventor has improved the adhesion between the base material / the lower primer layer / the elastic layer by the methods 1 to 4 shown below, and the peeling during use of the printer (copier) is improved. It was found that the occurrence can be prevented.

Method 1
The method according to claim 2, that is, a method in which metallic silicon is mainly used as a filler and the amount of CNT is optimized.

Method 2
This is a method of optimizing the type of filler and the amount of filler and CNT blended. Specifically, the elastic layer is composed of 5-20% by volume of silica (relative to the volume of the elastic layer), 10-40% by volume of boron nitride (boron nitride), and 0.1-2 volume of CNT. % In the range.

Method 3
In this method, silicone rubber is selected as the rubber constituting the elastic layer, and an appropriate amount of an adhesive component is added to the silicone rubber. As a result of the study, the inventor has added a specific adhesive component to the elastic layer in an appropriate amount, that is, within the following range, thereby improving the adhesion without impairing the high thermal conductivity and sufficient rubber elasticity. It has been found that the durability of is increased.

  Claims 7 and 8 are fixing belts obtained by this method. Claim 7 is that the base material and the elastic layer are bonded by a lower primer layer, and the rubber constituting the elastic layer is silicone rubber. The fixing layer according to any one of claims 1 to 6, wherein the elastic layer contains a silane coupling agent in an amount of 0.5 to 5 wt% with respect to the silicone rubber. And a rubber constituting the elastic layer is a silicone rubber, and the elastic layer is a resin for a rubber-based primer. The fixing belt according to any one of claims 1 to 6, wherein 0.1 to 3% by weight of rubber is blended.

  Here, as the silane coupling agent, for example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ- In the molecule, such as mercaptopropyltrimethoxysilane, reactive groups that chemically bond to inorganic substances (methoxy group, ethoxy group, silanol group, etc.) and reactive groups that chemically bond to organic materials (vinyl group, epoxy group, methacryl group, amino group) And organosilicon compounds having a mercapto group and the like. Especially, what has a methoxy group and an epoxy group is preferable, and what can be marketed under brand names, such as KBE-403 (made by Shin-Etsu Silicone), can be used for these.

  Although what is marketed can be used as resin for rubber | gum type | system | groups, Preferably the kind is selected according to a base material. For example, if the base material is a metal, X-33-173 (manufactured by Shin-Etsu Silicone Co., Ltd.) can be cited as a preferable rubber-based primer resin. If the base material is a resin such as polyimide, X-33 -174 (manufactured by Shin-Etsu Silicone).

Method 4
In this method, silicone rubber is selected as the rubber constituting the elastic layer, and silicone rubber is added to the primer layer. Claim 9 is a fixing belt obtained by this method, wherein the base material and the elastic layer are bonded together by a lower primer layer, the rubber constituting the elastic layer is silicone rubber, The fixing belt according to any one of claims 1 to 6, wherein silicone rubber is added.

  Although there is no restriction | limiting in particular in the kind of silicone rubber, The rubber | gum which does not have many filler amounts and has strong adhesive force is preferable. The amount of silicone rubber added is preferably about 0.1 to 30% by weight with respect to the lower primer layer.

  The method for producing the fixing belt of the present invention is not particularly limited. For example, an elastic layer is formed by applying a heat-resistant elastomer such as silicone rubber or fluororubber with a dispenser on the outer peripheral side of a tubular base material or cylindrical base material which is the innermost layer, and then vulcanizing it, Further, it can be produced by applying a fluororesin dispersion thereon and heat-treating it to form a surface layer. Preferably, in order to improve the adhesion between the layers, a lower primer layer is formed on the outer peripheral surface of the base material before applying the heat-resistant elastomer, and an elastic layer is applied before applying the fluororesin dispersion. An upper primer layer is formed on the outer peripheral surface of the substrate.

  An elastic layer may be formed by creating a heat-shrinkable tube made of a heat-resistant elastomer compounded with a vulcanizing agent, covering the outer periphery of the substrate, and heat-shrinking the tube.

  The fixing belt of the present invention is used in a fixing unit of various image forming apparatuses. In the fixing unit, a heating source is provided in the fixing belt, and the fixing belt is opposed to and pressed against a pressure roller made of a rubber roller or the like. The toner is melted by heating and fixed.

  The fixing belt of the present invention has a high thermal conductivity that can achieve excellent fixing properties corresponding to the recent increase in printing speed, and can sufficiently wrap and melt and mix color toners. It has moderate elasticity. Furthermore, it is an excellent fixing belt without a decrease in mechanical strength.

FIG. 3 is a cross-sectional view orthogonal to a rotation axis of an example of a fixing belt of the present invention.

  Next, although the form for implementing this invention is demonstrated, the range of this invention is not limited only to this form, What was changed in the range which does not impair the meaning of this invention is also included in this invention. It is.

  FIG. 1 is a diagram schematically showing an example of a fixing belt (roller) according to the present invention, and is a cross-sectional view orthogonal to the rotation axis of the fixing belt. In FIG. 1, 1 is a base material, 3 is an elastic layer, and 5 is a surface layer. Furthermore, a primer layer 2 (lower primer) and a primer layer 4 (upper primer) are provided between the base material 1 and the elastic layer 3 and between the elastic layer 3 and the surface layer 5 for improving adhesion. .

  The base material 1 in the example of FIG. 1 is an endless belt made of a polyimide resin. In addition, as the substrate 1, a resin or metal cylinder or columnar solid (roller) can be used. As the resin material for the endless belt, polyamideimide resin or the like can be used instead of polyimide resin, but polyimide resin is preferable in terms of heat resistance, elastic modulus, strength, and the like.

  The substrate 1 is formed by applying an organic solvent solution (polyimide varnish) of a polyimide precursor (polyamic acid) in which an appropriate amount of a filler for improving thermal conductivity is blended to the outer peripheral surface of a metal cylindrical core body by a dispenser method. , Heated to about 350 ° C. to 450 ° C., and the precursor is dehydrated and ring-closed to form a polyimide. Examples of the polyimide varnish include Ube Industries U varnish S, and examples of the organic solvent include N-methyl-2-pyrrolidone and dimethylacetamide, but are not limited thereto.

  The thickness of the endless belt made of such a polyimide resin is preferably about 30 to 80 μm from the viewpoint of durability and elasticity.

  As described above, the elastic layer 3 is preferably made of silicone rubber or fluororubber having excellent heat resistance. In particular, the silicone rubber layer is disposed on the substrate 1 side, and a thickness of 20 to 100 μm is formed thereon. An elastic layer having a two-layer structure in which a fluororubber layer is disposed on the surface layer side is preferable from the viewpoint of heat resistance and adhesion to the surface layer. That is, since there is a fluoro rubber layer on the surface layer 5 side, it has excellent adhesiveness with the surface layer 5 using a fluororesin as a matrix material, and furthermore, the fluoro rubber has good heat resistance. Damage is prevented. Further, since a silicone rubber layer is provided on the base material 1 side, it is preferable also in terms of elasticity.

  In order to improve the fixing property, the elastic layer 3 is required to have excellent elasticity in the thickness direction. For this reason, the hardness of the elastic layer 3 is preferably 10 to 60, and more preferably 10 to 40, as measured by a spring type piece test A type defined in JIS K6301. preferable. The thickness of the elastic layer 3 is also preferably 0.1 to 0.5 mm, and more preferably 0.2 mm or more.

  In the prior art, it was difficult to satisfy both moderate elasticity and high thermal conductivity. However, the method of the present invention makes it possible to satisfy both, and as a result, it is possible to achieve faster color printing. Fixability that can be dealt with sufficiently has been obtained.

  The carbon nanotubes used in the present invention can be produced by methods such as arc discharge, laser ablation, plasma synthesis, electrolysis, electron beam irradiation, and vapor phase growth. In particular, carbon nanotubes produced by an arc discharge method, laser ablation method, or vapor phase growth method are preferable as a method for producing the carbon nanotubes used in the present invention because the shape such as diameter and length can be easily controlled. Among these, the vapor phase growth method is particularly preferable because it is particularly easy to control.

  Examples of carbon nanotubes produced by such a vapor phase growth method include those produced by Hyperion Catalysis International, Showa Denko, Nikkiso, Carbon Nanotech Institute, GSI Creos, etc. As a specific product, VGCF-H manufactured by Showa Denko KK can be exemplified.

  The short axis diameter of the carbon nanotube is not particularly limited, but is preferably 0.5 μm or less, more preferably 0.3 μm or less, and particularly preferably 0.2 μm or less. A smaller minor axis diameter is preferable because the number of fibers when the same weight is added increases and the effect of improving heat conduction is excellent. In addition, there are a wide variety of carbon nanotubes ranging from single-walled to multi-walled (multi-walled). The major axis diameter of the carbon nanotube is not particularly limited, but is preferably 50 μm or less, more preferably 40 μm or less, and particularly preferably 30 μm or less. If the minor axis diameter and the major axis diameter are out of this range, it tends to be difficult to balance thermal conductivity and mechanical strength.

  Examples of the fluororesin used as the material for the surface layer 5 provided on the outer peripheral side of the elastic layer 3 include tetrafluoroethylene resin (PTFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), and tetrafluoroethylene. -A hexafluoropropylene copolymer etc. are mentioned. In particular, it is preferable to use PTFE or PFA from the viewpoint of heat resistance.

  10-50 micrometers is preferable, as for the thickness of the surface layer 5 which consists of a fluororesin, More preferably, it is 10-35 micrometers, More preferably, it is 10-25 micrometers. If the thickness of the fluororesin layer is too thin, the durability is inferior, and as the number of copies increases, there is a risk of early wear and loss of mold releasability. When the thickness of the fluororesin layer is too thick, the surface of the fixing belt becomes hard and the fixing property of the color toner is lowered.

  The material of the primer layers 2 and 4 is not particularly limited, but from the viewpoint of adhesive strength, the primer layer 2 is preferably a rubber-based primer, and the primer layer 4 is preferably a fluorine-based primer.

Examples 1-9 and Comparative Examples 1-5
A fixing belt shown in FIG. 1 (that is, a fixing sleeve having a base material 1, a primer layer 2, an elastic layer 3, a primer layer 4, and a surface layer 5) was prepared by the following procedure.

[Preparation of Substrate 1]
Dispensing the organic solvent solution of polyimide precursor (polyimide varnish, manufactured by Ube Industries, trade name: U varnish S) with an appropriate amount of filler for improving thermal conductivity on the outer peripheral surface of a metal cylindrical core The precursor was dehydrated and ring-closed to form a polyimide by heating at 350 ° C. to 450 ° C., and then removed from the cylindrical core to obtain a tubular substrate 1. The substrate 1 has a thickness of 50 μm, an inner diameter of 26 mm, and a length of 24 cm.

[Primer layer 2]
X-33-174A / B (rubber primer) manufactured by Shin-Etsu Silicone was used.

[Production of Elastic Layer 3]
In the well-known silicone rubber whose side chain is methyl type, the filler and the carbon nanotube described in Table 1, Table 2 or Table 3 are mixed in the amount and mixing described in Table 1, Table 2 or Table 3 using three rolls. did. The obtained mixture was applied to the outer peripheral surface of the primer layer 2 with a dispenser and then molded by heat vulcanization to obtain an elastic layer 3 having a thickness of 275 μm. In addition, the filler and carbon nanotube which were used for preparation of the elastic layer 3 are shown below.

(filler)
1. Alumina: Alumina CB-A10 (trade name) manufactured by Showa Denko KK The shape of the alumina is a sphere, and the average particle size is 10 mm. (In the table below, indicated as “alumina”.)
2. Silica: FB-8S manufactured by Denki Kagaku Kogyo Co., Ltd. (trade name; average particle diameter of about 6.5 μm, spherical, indicated as “silica” in the following table)

(carbon nanotube)
This is a carbon nanotube VGCF-H (trade name) manufactured by Showa Denko. The carbon nanotube has a short axis diameter of 150 nm and a long axis diameter of 6 μm.

  The volume% X of the filler and the volume% Y of the carbon nanotube are values calculated from the respective weights used and the specific gravity of the silicone rubber, the filler and the carbon nanotube. When two or more kinds of fillers are used, X is the sum of the volume%.

[Primer layer 4]
855N-703 (fluorine primer) manufactured by DuPont was used.

[Preparation of surface layer 5]
A fluororesin paint (PFA: 855N-713 manufactured by DuPont) is applied on the primer layer 4 and treated at about 340 ° C. to form a surface layer 5 (fluororesin layer), and the fixing shown in FIG. A belt was obtained. The thickness of the fluororesin layer was 15 μm.

  For the fixing belt produced as described above, the fixing property, hardness and thermal conductivity, adhesion between the substrate 1 / primer layer 2 / elastic layer 3 are measured by the following methods, and a durability test is performed. went. The results are shown in Table 1, Table 2 and Table 3.

[Evaluation of fixability]
Using the produced fixing belt, a color image was actually printed and evaluated. The surface temperature during printing was 150 ° C., and the pressing force was 6 kg. In addition, the conditions for passing paper at the time of printing were determined by visually checking whether or not there was unevenness in color and whether or not there was unevenness by printing 10 sheets of A4 printing paper continuously at 25 sheets / minute. The results are shown in Table 1, Table 2, and Table 3 based on the following criteria.
A: There is no color unevenness and roughness.
○: There is no uneven color, but there is roughness.
X: Both color unevenness and roughness are present.

[Evaluation of hardness and thermal conductivity]
The hardness was measured with a JIS-A hardness meter according to JIS K 6253. The thermal conductivity was obtained by multiplying the thermal diffusivity obtained by measuring with a periodic heating method measuring device FTC-1 manufactured by ULVAC-RIKO and the specific heat measured by JIS K 7123 and the density measured by JIS K 7112A method. Value.

[Evaluation of adhesion]
Evaluation was made by measuring 180 ° C. peeling strength. Specifically, a base rubber (silicone rubber) film is formed on a polyimide base material to a predetermined thickness, and a sample in which the base rubber is attached to a substrate with an adhesive is cut to a width of 1 cm, and the polyimide base side Was pulled with a tensile tester, and the 180 degree peel strength between the polyimide base material and the base rubber interface was measured.

[Durability test]
A color image was actually printed using the produced fixing belt. The surface temperature during printing was 150 ° C., and the pressing force was 6 kg. In addition, the condition of paper passing at the time of printing is that A4 printing paper is continuously printed at 25 sheets / minute, and the presence / absence of peeling between the base material 1 / primer layer 2 / elastic layer 3 of the fixing belt is visually confirmed. Evaluation was made based on the following evaluation criteria.

[Evaluation criteria]
A: No peeling occurs at all.
○: Almost no peeling occurs.
(Triangle | delta): Although peeling may occur, it is a level which does not interfere with practical use.
X: A lot of peeling occurs and is not at a practical level.

  Table 1, Table 2 and Table 3 show the hardness index and the heat conduction index obtained from the volume% of the filler and the carbon nanotube, together with the evaluation results such as fixability. As is clear from the results of Tables 1, 2 and 3, excellent fixability was obtained in Comparative Example 1 in which no filler or carbon nanotube was blended, and in Comparative Example 2 and Comparative Example 4 having a thermal conductivity index of 170 or less. I can't. It is thought that the thermal conductivity is too low. Further, even in Comparative Examples 3 and 5 having a hardness index of 750 or more, excellent fixability cannot be obtained. This is probably because the elastic layer was too hard and the color toner was not sufficiently melted and mixed.

  On the other hand, in Examples 1 to 9, in which carbon nanotubes are blended and the hardness index and the heat conduction index are within the scope of the present invention, excellent fixing properties are obtained. In particular, Examples 2 and 3 having a thermal conductivity index in the range of 200 to 280 are excellent in fixability.

  In the above examples, alumina is blended as a filler, but other fillers such as silica, boron nitride, titanium oxide, and graphite, which are generally used in the same manner as alumina as a thermally conductive filler, are used. Even if an agent is used, it is considered that the same result as in the case of alumina can be obtained.

Examples 10-17
As the filler, metal silicon powder (trade name, manufactured by Kinsei Matec Co., Ltd .; M-Si # 600, crushed shape, average particle size of about 6.0 μm, used as “metal Si” in the following table) was used. A fixing belt shown in FIG. 1 was produced by the same method and procedure as in Example 2 except that the formulation shown in Table 4 or 5 was used. The fixing belt was measured for the above physical properties, and the results are shown in Tables 4 and 5.

  As is apparent from the results of Tables 4 and 5, in Examples 10 to 17 in which metal silicon powder was blended as a filler and the hardness index and thermal conductivity index were within the scope of the present invention, excellent fixability was obtained. It has been.

  Moreover, the adhesion strength between the base material 1 / primer layer 2 / elastic layer 3 and the durability test results in Examples 10 to 17 are far superior to those in Examples 1 to 9 in which alumina is blended as a filler. Table 4 and Table 5 show that the adhesion between the base material 1 / primer layer 2 / elastic layer 3 is improved and a fixing belt having excellent durability can be obtained by blending metal silicon powder as an agent. It is shown by the result.

Examples 18-20
In the production of the elastic layer 3, the same procedure as in Example 2 was performed except that KBE-403 (3-glycidoxypropyltrimethoxysilane, a silane coupling agent manufactured by Shin-Etsu Silicone) was added to the silicone rubber in the amount shown in Table 6. Thus, the fixing belt shown in FIG. 1 was produced. The fixing belt was measured for the above physical properties, and the results are shown in Table 6. In addition, in the table | surface, the addition amount of KBE-403 is represented by the weight part with respect to 100 weight part of silicone rubber.

  In Examples 18 to 20, the elastic layer 3 is formed of silicone rubber, and a silane coupling agent is further added (corresponding to claim 7). As shown in the results of Table 6, in Examples 18 to 20 in which the hardness index and the heat conduction index are within the scope of the present invention, excellent fixability is obtained. / Adhesion between elastic layers 3 and durability test results are superior to Example 2 under the same conditions except that no silane coupling agent is added. Accordingly, the results shown in Table 6 show that the adhesion between the substrate 1 / primer layer 2 / elastic layer 3 is improved by forming the elastic layer 3 with silicone rubber and adding a silane coupling agent. ing.

Examples 21-23
In the production of the elastic layer 3, the same procedure as in Example 14 was conducted, except that KBE-403 (3-glycidoxypropyltrimethoxysilane, a silane coupling agent manufactured by Shin-Etsu Silicone) was added to the silicone rubber in the amount shown in Table 7. Thus, the fixing belt shown in FIG. 1 was produced. The fixing belt was measured for the above physical properties, and the results are shown in Table 7. In addition, in the table | surface, the addition amount of KBE-403 is represented by the weight part with respect to 100 weight part of silicone rubber.

  In Examples 21 to 23, the elastic layer 3 is formed of silicone rubber and a silane coupling agent is further added (corresponding to claim 7), but metal silicon powder is further used as a filler. . As the results in Table 7 show, the adhesion between the substrate 1 / primer layer 2 / elastic layer 3 is further improved than in Examples 18-20.

Examples 24-26
In the production of the elastic layer 3, X-33-174A / B manufactured by Shin-Etsu Silicone Co., Ltd. (rubber-based primer, hereinafter sometimes abbreviated as X-33-174) is added to the silicone rubber in the amounts shown in Table 8. A fixing belt shown in FIG. 1 was produced in the same manner as in Example 2 except for the addition. The fixing belt was measured for the above physical properties, and the results are shown in Table 8. In addition, in the table | surface, the addition amount of X-33-174 is represented by the weight part with respect to 100 weight part of silicone rubber.

  In Examples 24 to 26, the elastic layer 3 is formed of silicone rubber, and a rubber-based primer resin is further added (corresponding to claim 8). As shown in the results of Table 8, in Examples 24-26, in which the hardness index and the thermal conductivity index are within the scope of the present invention, excellent fixability is obtained. / Adhesive strength between the elastic layers 3 and durability test results are superior to Example 2 under the same conditions except that no rubber primer resin is added. Accordingly, the results shown in Table 8 show that the adhesion force between the base material 1 / primer layer 2 / elastic layer 3 is improved by forming the elastic layer 3 of silicone rubber and further adding a resin for the rubber-based primer. Has been.

Examples 27-29
A fixing belt shown in FIG. 1 was prepared in the same manner as in Example 14 except that in the production of the elastic layer 3, X-33-174 was added to silicone rubber in the amount shown in Table 9. With respect to this fixing belt, the above physical properties were measured, and the results are shown in Table 9. In addition, in the table | surface, the addition amount of X-33-174 is represented by the weight part with respect to 100 weight part of silicone rubber.

  In Examples 27 to 29, the elastic layer 3 is formed of silicone rubber and a rubber primer resin is further added (corresponding to claim 8), but metal silicon powder is used as a filler. is there. As the results in Table 9 show, the adhesion between the substrate 1 / primer layer 2 / elastic layer 3 is further improved than in Examples 24-26.

Examples 30-32
The same silicone rubber as the silicone rubber used in the elastic layer (a well-known silicone rubber having a methyl side chain) was added to the primer layer 2 in the same manner as in Example 2 except that the amount shown in Table 10 was added. The fixing belt shown in FIG. 1 was produced. The fixing belt was measured for the above physical properties, and the results are shown in Table 10. In addition, in the table | surface, the addition amount of silicone rubber is represented by the weight part with respect to 100 weight part of X-33-174A / B (rubber-type primer) which forms the primer layer 2. FIG.

  Examples 30 to 32 are obtained by adding silicone rubber to the primer layer 2 (corresponding to claim 9). As shown in the results of Table 10, in Examples 30 to 32 in which the hardness index and the thermal conductivity index are within the scope of the present invention, excellent fixing properties are obtained. The adhesion between the elastic layers 3 and the durability test results are superior to those of Example 2 under the same conditions except that no silicone rubber is added to the primer layer 2. Accordingly, the results shown in Table 10 show that the adhesion between the substrate 1 / primer layer 2 / elastic layer 3 is improved by adding silicone rubber to the primer layer 2.

Examples 33-35
The same silicone rubber as the silicone rubber used for the elastic layer (a well-known silicone rubber having a methyl side chain) was added to the primer layer 2 in the same manner as in Example 14 except that the amount shown in Table 10 was added. The fixing belt shown in FIG. 1 was produced. The fixing belt was measured for the above physical properties, and the results are shown in Table 11. In addition, in the table | surface, the addition amount of silicone rubber is represented by the weight part with respect to 100 weight part of X-33-174A / B (rubber-type primer) which forms the primer layer 2. FIG.

  In Examples 33 to 35, silicone rubber was added to the primer layer 2 (corresponding to claim 9), but metal silicon powder was further used as a filler. As the result of Table 11 shows, the adhesive force between the base material 1 / primer layer 2 / elastic layer 3 is further improved as compared with Examples 30-32.

1 Base material 2 Lower primer layer 3 Elastic layer 4 Upper primer layer 5 Surface layer

Claims (8)

A fixing belt having a tubular base material, an elastic layer provided on the outer peripheral side of the base material, and a surface layer provided on the outer peripheral side surface of the elastic layer,
The elastic layer is formed by blending a silicone rubber with a filler for improving thermal conductivity and a carbon nanotube having a minor axis diameter of 0.2 μm or less and a major axis diameter of 30 μm or less,
In the elastic layer, when the total volume of the elastic layer is 100%, the proportion of the true volume of the filler improving the thermal conductivity of the (%) X, the ratio of the true volume of the carbon nanotubes (%) When Y
A fixing belt characterized by satisfying 3Y + 0.8X ≦ 62, 8Y + 0.5X ≧ 33, X ≦ 70, 24Y + 17X ≧ 750 and 10 ≧ Y> 0.1. The fixing belt according to claim 1, wherein the filler for improving the thermal conductivity is mainly composed of metal silicon powder. The fixing belt according to claim 1 , wherein the surface layer is made of a fluororesin. Wherein the substrate, the fixing belt according to any one of claims 1 to claim 3, characterized in that a metal tube or a heat resistant plastic tube. Fixing belt according to any one of claims 1 to claim 3 wherein the substrate, characterized in that it is a tube of polyimide or polyamide-imide. The elastic interlayer and the substrate are adhered by the lower primer layer, said elastic layer, claims 1, characterized in that the silane coupling agent is blended 0.5-5% by weight relative to the silicone rubber according Item 6. The fixing belt according to any one of Items 5 to 6. The said base material and the said elastic layer are adhere | attached by the lower primer layer, and the said elastic layer mix | blends 0.1 to 3 weight% of rubber-type primer resin with respect to the said silicone rubber. The fixing belt according to claim 5 . It said substrate and said elastic layers are bonded by the lower primer layer, wherein the lower primer, fixing belt according to any one of claims 1 to claim 5, characterized in that the addition of silicone rubber.

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