JP2015004790A - Fixing member, fixing apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing member configured to prevent a wrinkle and an abnormal image from being formed during fixation of a transfer sheet.SOLUTION: A fixing member for heating a toner image carried on a recording material to fix the toner image includes an elastic layer 202 formed on a base material at least. The elastic layer is formed of heat-resistant rubber containing a fibrous filler 204 having high heat conductivity. The heat-resistant rubber includes hole sections 205. Universal hardness of the surface at an axial end of the fixing member is made larger than that of the surface at the central part.

Description

  The present invention relates to a fixing device provided in an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile, and a fixing member provided in the fixing device.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine, a printer, or a facsimile that employs an electrophotographic method usually has a rotating photosensitive drum, and the photosensitive layer of the photosensitive drum is uniformly charged. Thereafter, an electrostatic latent image is formed by exposure with a laser beam from a laser scanning unit. Further, a mechanism is provided in which the electrostatic latent image is developed with toner and then transferred onto a transfer sheet as a recording material, and the transfer sheet is further passed through a heat fixing device and thermally fixed.

  In general, as a fixing method, a recording sheet is passed between a fixing member (a fixing roller, a fixing belt, or a fixing sleeve) that heats toner and a pressure roller that presses the fixing member. A fixing method is adopted in which a toner image is fixed on a recording sheet by pressurizing the toner being softened by heat. In this fixing method, since the toner image fused to the paper comes into contact with the fixing member, a material having good releasability (for example, a fluorine resin) is formed on the surface with a film thickness of 5 to 30 μm.

  Conventionally, a roller system has been used, but in recent years it is necessary to form an elastic layer having sufficient elasticity as an intermediate layer in order to obtain a heating time and followability suitable for color images. Has been put into practical use (Patent Document 1 (US Pat. No. 3,578,797)).

In recent years, a heat-resistant sleeve has a heating member and a pressure member fixed to a metal or resin holder, and the toner image is fixed in a recording sheet shape by heating the recording sheet through the sleeve. (Sleeve fixing method) has been devised.
The configuration of A in FIG. 5 is disclosed, for example, in Patent Document 2 (Japanese Patent Laid-Open No. 2011-59247). A halogen heater is used as the heating body 304, a pressure member 306 is fixed to the holder 305, the heating source and the pressure member are separated from each other, and a nip is formed by pressure rollers 307-309. The configuration B is disclosed, for example, in Patent Document 3 (Japanese Patent Laid-Open No. 63-313182). In the heat-resistant sleeve, there are a planar heating element 310 and a pressure member 306 fixed to a holder, and a nip is similarly formed by a pressure roller. In this structure, the heating body and the pressure member are integrated, and the time to reach the fixing set temperature is shortened. Further, the heating body and the pressure member do not necessarily have to be in the same sleeve, and can be formed in the opposed rollers. That is, the configuration of C in FIG. 5 is disclosed, for example, in Patent Document 4 (Japanese Patent No. 3298354). This method is excellent in paper separability.

  In this type of apparatus, generally, a sheet is sandwiched between a fixing roller and a pressure roller and transported, and the moisture contained in the sheet is evaporated at that time. Wrinkle generation due to a change in the amount of water between the part and the unfixed part is a problem. As a method of preventing wrinkling of the paper, the roller end is formed into a drum shape (inverse crown shape in cross section) so that the central portion of the roller has a minimum diameter and gradually increases toward both ends, and the roller end portion There is a method of giving a force (drum effect) that spreads to both ends of the paper by making the paper transport speed of the paper faster than the transport speed of the central portion. This is because the outer diameter of both end portions is larger than the outer diameter of the central portion, the conveying speed of the roller end portion is larger than the conveying speed of the central portion, and the force that pulls the both end portions outward on the paper P Due to being given. However, with this method, it is difficult to process the elastic layer into a crown shape. In addition to the problems of high accuracy and high cost, the accurate drum shape cannot be maintained due to the difference in thermal expansion, and the wrinkle prevention effect is not stable. Not only that, but in the worst case, the surface release layer is peeled off, parts are damaged, and problems such as transfer paper jam occur.

Furthermore, there is a project that proposed a similar wrinkle prevention effect by using a roller having a hardness difference in the axial direction.
For example, Patent Document 5 (Japanese Patent Laid-Open No. 2009-276499) describes “an elastic roller characterized in that the Asker C hardness at both ends is larger than the Asker C hardness at the center”. However, it is said that the elastic layer thickness is 2 to 20 mm and is formed on the shaft body, and the foaming ratio is controlled, the heat insulation performance changes in the axial direction, and heat stays (particularly between the paper passing portion and the non-paper passing portion). Due to the difference in temperature difference, a stable wrinkle prevention effect such as a change in roller diameter cannot be obtained.

  Further, Patent Document 6 (Japanese Patent Application Laid-Open No. 7-219374) states that “the hardness of the outer peripheral surface of the pressure roller is different between the axial central portion and the shaft end portion, and the hardness of the outer peripheral surface of the axial central portion is the axis. It is said that the hardness is lower than the hardness of the outer peripheral surface of the end portion. However, the above-mentioned document is a matter relating to the pressure roller and is different in configuration from this case. Further, since foamed rubber not containing a heat conductive filler is used, heat is accumulated, the roller diameter is changed, and an abnormal image due to heat unevenness during paper passing is expected to occur.

  An object of the present invention is to provide a fixing member capable of preventing both wrinkles and abnormal images during fixing of transfer paper.

As a result of intensive studies, the present inventors have found that the above-described problems can be solved by the following fixing member, and have reached the present invention.
That is, the present invention is as follows.
A fixing member for heating a toner image carried on a recording material to fix the toner image, having at least an elastic layer on a base material, and the elastic layer including a high thermal conductive fibrous filler A fixing member comprising a heat-resistant rubber, having a hole in the heat-resistant rubber, wherein the universal hardness of the surface of the fixing member in the axial direction is larger than the universal hardness of the surface of the central portion.

  The fixing member of the present invention can prevent both wrinkles and abnormal images when fixing transfer paper.

FIG. 2 is a diagram schematically illustrating an image forming apparatus and a belt-type fixing device. FIG. 3 is a cross-sectional view illustrating an outline of an example of a configuration of a fixing member. It is a schematic diagram of an example of a fixing member in the present invention. It is a schematic diagram of an example of a method for producing a fixing member of the present invention. 2 is a cross-sectional view illustrating an outline of a configuration of a fixing member.

The details of the present invention will be described below.
The fixing member of the present invention is a fixing member for heating a toner image carried on a recording material to fix the toner image, and has an elastic layer on at least a base material, and the elastic layer has a high heat The heat-resistant rubber is composed of a heat-resistant rubber containing a conductive fibrous filler. The heat-resistant rubber has pores, and the universal hardness of the fixing member axial end surface is larger than the universal hardness of the central surface.
The present invention relates to a material structure of the heat fixing member, and by making the universal hardness of the end surface of the member having high thermal conductivity and low heat capacity larger than the universal hardness of the central surface, the wrinkles of the transfer paper and Both abnormal images can be prevented.

The universal hardness of the fixing member can be measured according to DIN50359 using a commercially available hardness measuring device. For example, it can be measured using an ultra micro hardness meter. Examples of the ultra-small hardness meter include Fischerscope H100 (manufactured by Fischer Instruments).
When measuring universal hardness using an ultra-micro hardness meter, for example, the load when the indenter reaches the desired depth by gradually pushing the indenter into the fixing member to the specified indentation depth under the following conditions: The universal hardness is obtained from the contact area of the indenter. In this case, the universal hardness when indented 10 μm was compared.
-Measurement conditions-
・ Indenter: Square pyramid diamond indenter with face-to-face angle of 136 degrees ・ Initial load: 0.02 mN
・ Maximum load: 5mN ~ 400mN
Load increase time from initial load to maximum load: 10 seconds to 60 seconds Note that the surface of the fixing member for measuring universal hardness is a release layer when the fixing member has a release layer on the elastic layer. Become. When the surface is a release layer, the universal hardness is measured when indented by 10 μm. However, the release layer does not have to have the thickness, and the hardness may be measured with the influence of the elastic layer. Regardless of the presence or absence of the release layer, if the universal hardness of the fixing member end surface is greater than the universal hardness of the central surface, the effect of the present invention is exhibited.

As described above, in Patent Document 5, a roller having a hardness difference in the axial direction is used and a similar wrinkle prevention effect is proposed, but the elastic layer film thickness is 2 to 20 mm and is formed on the shaft body. Since the hardness difference is provided by controlling the expansion ratio, the roller diameter changes and a stable wrinkle prevention effect cannot be obtained.
The fixing member of the present invention can be a member having high thermal conductivity and low heat capacity (high thermal diffusivity) in the axial direction because the elastic layer contains a highly heat conductive fibrous filler and has a void portion. Retention can be prevented. Further, in the fixing member of the present invention, the elastic layer can be a thin film (about 100 to 300 μm), and a large change in diameter does not occur. Furthermore, by providing these functions, a stable wrinkle prevention effect can be obtained. And since it is a thin film, it did not produce a difference in Asker C hardness, but it confirmed that a wrinkle prevention effect was acquired by giving the micro area hardness difference confirmed by universal hardness. In addition, it is possible to simultaneously achieve effects such as shortening of the rise time, prevention of abnormal images, and suppression of end temperature rise.

As a method of making the universal hardness of the fixing member axial end surface larger than the universal hardness of the central surface, the hardness can be changed by changing the expansion ratio, but it is contained in the fixing member axial end of the elastic layer. It is preferable to achieve this by making the content of the high thermal conductive fibrous filler greater than the content of the high thermal conductive fibrous filler contained in the central portion.
Lowering the addition amount of the high specific gravity fibrous filler having a high specific gravity contained in the central portion further contributes to shortening the rise time.
In addition, the universal hardness of the fixing member when the surface of the axial end portion is pushed by 10 μm is 0.5 N / mm ² or less, and the difference in hardness between the axial end portion and the central portion is 0 by the universal hardness when pushing by 10 μm. .1N / mm ² or more 0.4 N / mm ² or less is preferably.
By controlling the hardness, occurrence of abnormal images can be suppressed.
Said end portion has a hardness of 0.5 N / mm ² or less of, and the hardness difference between the axial end portion and the central portion is at 0.1 N / mm ² or more 0.4 N / mm ² or less, the paper It is possible to prevent the occurrence of an abnormal image cold offset due to the deterioration of the follow-up performance.
Furthermore, the hardness of the central portion is more preferably 0.1 N / mm ² or more. When the hardness of the central portion is 0.1 N / mm ² or more, the nip width is increased and the paper is properly tracked, and abnormal image hot offset due to excessive heat applied to the toner can be prevented.

Preferably, the high thermal conductive fibrous filler is oriented in the axial direction of the fixing member, and the high thermal conductive fibrous filler is oriented in the axial direction of the fixing member, thereby improving the thermal conductivity in the axial direction, It is possible to suppress the end temperature rise and prevent the wrinkles and the pressure roller from being damaged.
Therefore, by using the fixing member of the present invention, it is possible to provide a fixing device that has improved durability and reliability.
In addition, by using the fixing device of the present invention, it is possible to provide a highly durable and highly reliable image forming apparatus such as an electrophotographic copying machine, a facsimile machine, and a laser beam printer, which can contribute to "improvement of customer satisfaction". .

First, an outline of an image forming apparatus in which the fixing member of the present invention is used will be described.
FIG. 1 is an example conceptually showing the structure of a photoreceptor of an image forming apparatus, its image forming system, and a fixing device. In this electrophotographic image forming apparatus, the photosensitive layer of the rotating photosensitive drum 101 is uniformly charged using a charging roller 102 and then exposed by a laser beam 103 from a laser scanning unit (not shown). Then, an electrostatic latent image is formed. Next, the electrostatic latent image on the photosensitive drum 101 is developed with toner to form a toner image, the toner image is transferred onto the recording sheet 107, and the recording sheet 107 is passed through a fixing device to heat the toner image. It is configured to press and fix to the recording sheet.
In FIG. 1A, reference numeral 104 denotes a developing roller, 105 denotes a power pack (power source), 106 denotes a transfer roller, 108 denotes a cleaning device, and 109 denotes a surface potential meter.

  The fixing device uses a heat fixing roller 110 including a base material and an elastic layer provided on the base material. In such a heat fixing roller 110, a heater such as a halogen lamp is disposed along the rotation center line in the hollow portion of the core metal, and the heat fixing roller 110 is heated from the inside by its radiant heat. In addition, a pressure roller 111 that is in pressure contact with the heat fixing roller 110 is provided in parallel, and the recording sheet is passed between the pressure roller 111 and the heat fixing roller 110 so that the toner adhered on the recording sheet. The toner image is fixed on the recording sheet by being pressed by being sandwiched between the pressure roller 111 and the heat fixing roller 110 while being softened by the heat of the heat fixing roller 110.

  In the present invention, the fixing device may be a belt-type fixing device. In FIG. 1B, 113 is a fixing belt, 114 is a fixing roller, 115 is a pressure roller, and 116 is a heating roller. Here, in full-color copying machines and laser printers, four color toners of magenta, cyan, yellow, and black are used. When fixing a color image, these color toners must be mixed in a molten state. Therefore, it is necessary to lower the melting point of the toner to facilitate melting, and to uniformly mix in a molten state so as to enclose a plurality of types of color toners on the surface of the fixing belt 113. (In the present invention, the fixing roller, the fixing belt, and the fixing sleeve are collectively referred to as a fixing member.) The fixing belt as a heat generating member is stretched and supported by a fixing roller (114) and a heating roller (116).

FIG. 2 is a schematic view showing an example of the configuration of the fixing member, and the fixing member includes a base material 201, an elastic layer 202, and a release layer 203. It is preferable to have a release layer.
The base material 201 is made of a heat-resistant material, and for example, a resin material such as polyimide, polyamideimide, PEEK, PES, PPS, or fluorine resin can be used. A resin material in which magnetic conductive particles are dispersed can also be used. In that case, magnetic conductive particles are added within a range of 20 to 90% by weight with respect to the resin material. Specifically, the magnetic conductive particles are dispersed in a resin material in a varnish state using a dispersing device such as a roll mill, a sand mill, or a centrifugal defoaming device. This is adjusted to an appropriate viscosity with a solvent and formed into a desired layer thickness with a mold. Also, it can be formed of metal (this is a sleeve that is distinguished from a roller), specifically, an alloy of nickel, iron, and chrome, and may itself generate heat. The layer thickness of the base material is 30 to 500 μm from the viewpoint of heat capacity and strength.

  In the case of a metal material, it is desirable that the film thickness is 100 μm or less in consideration of the bending of the belt. In the case of a metal material, the desired Curie point can be obtained by adjusting the amount of each material added and the processing conditions. The heat generating layer is formed of a magnetic conductive material in which the Curie point is close to the fixing temperature of the fixing belt. By forming, the heat generating layer can be heated without being overheated by electromagnetic induction. It can also be formed of an elastic body, for example, natural rubber, SBR, butyl rubber, chloroprene rubber, nitrile rubber, acrylic rubber, urethane rubber, silicone rubber, fluorosilicone rubber, fluorine rubber, liquid fluorine elastomer, etc. From the viewpoint of properties, silicone rubber, fluorosilicone rubber, fluorine rubber, fluorocarbon siloxane rubber, liquid fluorine elastomer and the like are preferable.

  The elastic layer 202 formed on the substrate is made of a heat-resistant elastic body, preferably a heat-resistant rubber. For example, natural rubber, SBR, butyl rubber, chloroprene rubber, nitrile rubber, acrylic rubber, urethane rubber Silicone rubber, fluorosilicone rubber, fluorine rubber, liquid fluoroelastomer, and the like can be raised, and silicone rubber, fluorosilicone rubber, fluororubber, fluorocarbonsiloxane rubber, liquid fluoroelastomer, and the like are particularly preferable from the viewpoint of heat resistance. In particular, silicone rubber and fluorosilicone rubber are preferable from the viewpoint of heat resistance and wettability of the release agent.

In these elastic layers, a high thermal conductive fibrous filler 204 and a hole portion 205 are provided.
As the high thermal conductive fibrous filler 204, various metal fillers such as carbon fiber, boron nitride, alumina, silicon nitride, aluminum nitride, and silver can be considered. Among them, for example, carbon fibers include PAN (polyacrylonitrile) carbon fibers made from synthetic acrylic long fibers and pitch carbon fibers made from coal tar and petroleum pitch. The PAN-based carbon fiber is obtained by carbonizing a PAN precursor (polyacrylonitrile fiber) and has properties of high strength and high elastic modulus. Pitch-based carbon fiber is obtained by carbonizing a pitch precursor (pitch fiber obtained from coal tar or heavy petroleum oil as a raw material). Under various conditions of the manufacturing method, it can be obtained from low modulus to ultra-high modulus and high strength. A wide range of properties can be obtained. Ultra-high modulus products have excellent thermal conductivity and conductivity characteristics, as well as high rigidity applications. In the present invention, pitch-based carbon fibers are preferably used from the viewpoint of thermal conductivity.

The foaming agent that forms the pores 205 is azobisisobutyronitrile (AIBN) or the like, and the foamed particles are Matsumoto Yuka Pharmaceutical F-30, F-30VS, F-46, F-50. , F-55, etc. Examples of the resin balloon include Matsumoto Yuka Pharmaceutical F-80ED. Examples of inorganic balloons include Nippon Philite Co., Ltd .: Philite, Pacific Coal Sales and Transportation Co., Ltd .: Silica Balloon, and the like.
The foaming agent is preferably added so that the pores in the elastic layer are 50% to 200% of the original volume.
Note that the ratio of the hole portions in the axial end portion and the central portion of the fixing member may be the same or different. If the universal hardness of the fixing member axial end surface is larger than the universal hardness of the central surface, the effect of the present invention is stated.

The method for forming the elastic layer is not particularly limited and may be appropriately selected depending on the purpose. For example, a coating liquid containing the high thermal conductive fibrous filler, a foaming agent, and a heat resistant rubber may be used as a blade coating method. , Roll coating method, die coating method, etc. can be applied to the substrate and heated to form an elastic layer with pores, but the coating direction is the axial direction and the coating is seamless in the circumferential direction A method is preferred. By carrying out like this, the effect which accelerates | stimulates that the filler in an elastic layer orients to an axial direction can be anticipated.
There is no restriction | limiting in particular in the thickness of the said elastic layer, According to the objective, it can select suitably, 100 micrometers-500 micrometers are preferable.

Whether or not the high thermal conductive fibrous filler is oriented can be confirmed with a laser microscope.
For example, the orientation of the carbon fiber was measured using a KEYENCE microscope: VHX-1000 zoom lens: VH-Z100R, and a range of 800 μm × 600 μm was determined with a lens having an objective magnification of 300 times. For carbon fibers having a length of 100 μm or more in this range, the deflection angle is measured with respect to the axial direction, and the ratio of the carbon fibers within the deflection angle of 30 ° on both sides is 50% or more of the whole. Oriented ".

The fixing member in which the universal hardness of the fixing member axial end surface is larger than the universal hardness of the central surface, for example, the content of the high thermal conductive fibrous filler contained in the fixing member axial end of the elastic layer is It can obtain by making more than content of the highly heat conductive fibrous filler contained in. A fixing member having such an elastic layer can be produced as follows.
First, an elastic layer is formed on a substrate, and the thermally conductive fibrous filler is, for example, a part that abuts on the small-size recording material passing width (see FIG. 3 for example: vertical passing paper with a small-size recording material passing width of B5 (width In the case of 182 mm), the compounding ratio is changed between the center part 301 and the shaft end part 302 with a boundary of ± 85 mm width from the center, and the compounding at the center part is rubber A and the compounding at the shaft end part is rubber B. After the film formed at the central portion with the rubber A is first vulcanized, the rubber B is dipped in the same manner. The coating method is not limited to this, and it is sufficient that shearing is applied in the axial direction. For example, an extrusion method using die coating can be considered. Then, it heats and vulcanizes. After that, the whole is ground to a desired film thickness to make an elastic layer. Thereafter, a release layer is formed, and the end portion is cut to have a desired length. (See Figure 4)
According to this molding method, it is known that carbon fibers that are fibrous fillers are oriented in the coating axis direction.

As shown in FIG. 3, the central portion is preferably arranged in a region corresponding to the small-size recording material sheet passing width (the minimum sheet passing width to be supported). The central part is preferably a part slightly smaller than the passing width of the small-size recording material. For example, the central part is from L / 2 mm (L / 2) of “recording paper having the minimum passing width L” from the center of the fixing member. −10) It is preferably formed in a range of mm. Specifically, when the paper passing width of the small size recording material is 182 mm of B5 vertical paper passing, the central portion has a range of ± (91 to 81) mm from the center toward the axial direction, for example, about ± 85 mm. It is preferable that it is the range of these.
By making the center part a little smaller than the width of the small-size recording material, the edge of the paper is slightly in contact with the hard part. Is suppressed.
FIG. 3 shows an example in which rubber A is blended at the center of the elastic layer and rubber B is blended at the end of the shaft, so that one kind of hardness difference is provided in two types. The end may be gradually increased in hardness by several stages. For example, you may provide a hardness difference in all the edge parts of corresponding size paper. By producing the elastic layer in multiple stages with rubbers A, B, C, and D, the hardness difference can be gradually increased.

The content of the high thermal conductive fibrous filler contained in the end portion of the elastic member in the fixing member axial direction is such that the universal hardness when the surface of the fixing member axial end portion is pressed by 10 μm is 0.5 N / mm ² or less. It is preferable to contain.
The universal hardness when the surface of the end portion in the axial direction of the fixing member is pressed by 10 μm is more preferably 0.2 to 0.5 N / mm ² .
In addition, the content of the high thermal conductive fibrous filler contained in the axially central portion of the fixing member of the elastic layer is 0.1 N / mm in terms of universal hardness when the hardness difference between the axial end and the central portion is 10 μm. It is preferable to make it contain so that it may become ² or more and 0.4 N / mm < ² > or less.

Further, the release layer 203 formed on the elastic layer is formed of, for example, tetrafluoroethylene resin (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin (PFA), tetrafluoroethylene / hexafluoroethylene. Fluorinated polymers such as fluorinated propylene copolymer (FEP); mixtures of these polymers, or dispersions of these polymers in heat-resistant resins and rubbers, and fluorine having fluorinated polyethers in silicone cross-linking reactive groups Series elastomers can be applied. Among these, those having a fluorine-based polymer are particularly preferable from the viewpoint of achieving both strength and smoothness. A hollow filler, a conductive substance, or the like can be added to the release layer as a substance having low specific heat and low thermal conductivity. A method for forming the release layer is not particularly limited and may be appropriately selected depending on the purpose. For example, a tube-shaped elastic layer may be covered with a wet spray coating method, after powder coating. The method of baking, etc. are mentioned.
The thickness of the release layer is preferably 0.01 μm to 50 μm, and more preferably 0.01 μm to 30 μm. If the thickness is less than 0.01 μm, the film formability may not be ensured due to the roughness of the elastic layer. If the thickness exceeds 50 μm, a step is formed in the image and an image defect due to gloss difference is formed. Sometimes.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to a following example.

[Example 1]
Hereinafter, the present invention will be described in more detail based on experimental results.
As a fixing member of the fixing device, a base material: φ30, a thickness of 50 μm, a silicone rubber (DY35-2083: manufactured by Toray), a filler, a foaming agent and a solvent (toluene) are mixed as an elastic layer, and a viscosity of about 100 Pa · sec The rubber diluted to (Shalayate 0.115) was dipped with a coating speed of about 10 mm / min and a film thickness of about 300 μm.
The filler consists of carbon fiber (Nippon Graphite Co., Ltd. XN-100-05M) as a high thermal conductive fibrous filler, and a hollow filler (Matsumoto Yuka Pharmaceutical: PAN F-80ED) as a foaming agent. (Mass part relative to 100 parts by mass of base silicone rubber)
The carbon fiber corresponds to a portion that abuts the small size recording material passage width (see FIG. 3: in the embodiment, A4 vertical paper is the small size recording material passage width), and the central portion (in the axial direction from the center of the fixing member) The range is within a range of ± 100 mm) and the shaft end portion (portion other than the central portion), and the blending at the central portion is rubber A and the blending at the shaft end portion is rubber B. The film formed at the center with the rubber A is first vulcanized at 120 ° C. for 30 minutes, and then the rubber B is dipped in the same manner. Thereafter, heating is performed at 120 ° C. for 30 minutes, followed by heating at 200 ° C. for 4 hours to vulcanize. After that, the whole is ground to a film thickness of 200 ± 20 μm to be an elastic layer. After that, the primer was applied and dried at 100 ° C. or more for 1 hour, covered with Gunze PFA tube (Mitsui DuPont Fluorochemical PFA-350J, φ30, film thickness 15 μm), heat-welded at 320 ° C. for 40 minutes, end The fixing sleeve was obtained by cutting the portion and aligning it to a desired length. (See Figure 4)
According to this molding method, it is known that carbon fibers that are fibrous fillers are oriented in the coating axis direction.

Here, the universal hardness of the surface of the fixing sleeve can be measured in accordance with DIN50359 using a commercially available hardness measuring device, and an ultra-micro hardness meter (Fischer Scope H100, manufactured by Fisher Instruments Co., Ltd.) is used. Measured. When measuring the universal hardness using an ultra-micro hardness tester, the indenter is gradually pushed into the fixing member to the prescribed indentation depth under the following conditions, and the load when the indentation depth reaches the desired depth Determine the universal hardness from the contact area of the indenter. In this case, the universal hardness at 10 μm indentation was obtained and compared. (See Table 1)
-Measurement conditions-
・ Indenter: Square pyramid diamond indenter with face-to-face angle of 136 degrees ・ Initial load: 0.02 mN
・ Maximum load: 5mN ~ 400mN
・ Load increase time from initial load to maximum load: 10 to 60 seconds

  The fixing member manufactured as described above was mounted on a fixing device of a copying machine manufactured by Ricoh Co., Ltd .: imagio MP C2201SP, and 120K toner solid images were passed through A4 portrait on both sides for evaluation. Since the imagio MP C2201SP is an A3 (A4 horizontal) width compatible machine, the maximum size recording material passing width is A4 horizontal width, and the A4 vertical passing paper is small size recording material passing paper. As a test paper, ASKUL: Multi Paper Super White was used. Evaluation was made based on the criteria shown in Table 2.

[Example 2]
A fixing member was prepared in the same manner as in Example 1 except that the carbon fiber compounding ratio of the elastic layer in Example 1 was changed to 10 parts by mass of the central part and 50 parts by mass of the shaft end part with respect to 100 parts by mass of the silicone rubber. Evaluation was performed.
[Example 3]
A fixing member was prepared in the same manner as in Example 1 except that the carbon fiber compounding ratio of the elastic layer in Example 1 was changed to 40 parts by mass of the central part and 50 parts by mass of the shaft end part with respect to 100 parts by mass of the silicone rubber. Evaluation was performed.
[Example 4]
A fixing member was prepared in the same manner as in Example 1 except that the carbon fiber compounding ratio of the elastic layer in Example 1 was changed to 10 parts by mass of the central part and 30 parts by mass of the shaft end part with respect to 100 parts by mass of the silicone rubber. Evaluation was performed.
[Example 5]
A fixing member was prepared in the same manner as in Example 1 except that the carbon fiber compounding ratio of the elastic layer in Example 1 was changed to 40 parts by mass of the central part and 60 parts by mass of the shaft end part with respect to 100 parts by mass of the silicone rubber. Evaluation was performed.
[Example 6]
A fixing member was produced in the same manner as in Example 1 except that the carbon fiber compounding ratio of the elastic layer in Example 1 was changed to 5 parts by mass of the center part and 50 parts by mass of the shaft end part with respect to 100 parts by mass of the silicone rubber. Evaluation was performed.

[Comparative Example 1]
A fixing member was prepared in the same manner as in Example 1 except that the carbon fiber compounding ratio of the elastic layer in Example 1 was changed to 20 parts by mass of the center part and 20 parts by mass of the shaft end part with respect to 100 parts by mass of the silicone rubber. Evaluation was performed.

In the evaluation of the rise time, as a ready-made product, comparison was made using a fixing sleeve in which only a heat-resistant silicone rubber was formed as an elastic layer and a fluororesin was coated thereon as a release layer.

From the above, the following can be understood.
-Wrinkles can be prevented by making the universal hardness of the axial end surface of the fixing member larger than the universal hardness of the center surface.

Furthermore, the universal hardness of the shaft end surface is 0.5 N / mm ² or less, and the hardness difference between the axial end surface and the central surface is the universal hardness. With 0.1 N / mm ² or more 0.4 N / mm ² or less is fixing member, to prevent wrinkles of the transfer paper, to reduce the rise time can be suppressed end temperature rise to prevent abnormal images. Therefore, wrinkles can be prevented without forming a complicated crown shape, and the release layer can be prevented from being broken due to a difference in thermal expansion or a difference in linear velocity by a thin and uniform elastic layer, so that the life of the fixing member can be suppressed.
As a result, since the fixing member of the present invention achieves both high image quality and high reliability and can achieve stable fixing for a long time, by using the fixing device equipped with the fixing member of the present invention, durability and reliability can be improved. It is possible to provide a fixing device that realizes improvements and the like. Furthermore, by having this fixing device, image forming apparatuses such as electrophotographic copying machines, facsimiles, and laser beam printers having high durability and high reliability are possible, which contributes to “improvement of customer satisfaction”.

DESCRIPTION OF SYMBOLS 101 Photosensitive drum 102 Charging roller 103 Exposure 104 Developing roller 105 Power pack 106 Transfer roller 107 Recording sheet 108 Cleaning device 109 Surface potential meter 110 Heating fixing roller 111 Pressure roller 112 Belt type fixing device 113 Fixing belt 114 Fixing roller 115 Pressure Roller 116 Heating roller 201 Base material 202 Elastic layer 203 Release layer 204 High thermal conductive filler 205 Air hole portion 301 Elastic layer formed of rubber A 302 Elastic layer formed of rubber B

U.S. Pat. No. 3,578,797 JP 2011-59247 A JP-A-63-313182 Japanese Patent No. 3298354 JP 2009-276499 A JP 7-219374 A

Claims (6)

  A fixing member for heating a toner image carried on a recording material to fix the toner image, having at least an elastic layer on a base material, and the elastic layer including a high thermal conductive fibrous filler A fixing member comprising a heat-resistant rubber, having a hole in the heat-resistant rubber, wherein the universal hardness of the surface of the fixing member in the axial direction is larger than the universal hardness of the surface of the central portion.   The content of the high thermal conductive fibrous filler contained in the fixing member axial end portion of the elastic layer is larger than the content of the high thermal conductive fibrous filler contained in the central portion. Fixing member. The universal hardness when the axial end surface of the fixing member is pressed by 10 μm is 0.5 N / mm ² or less, and the difference in hardness between the axial end surface and the central surface is 10 μm. in fixing member according to claim 1 or 2, characterized in that 0.1 N / mm ² or more 0.4 N / mm ² or less.   The fixing member according to claim 1, wherein the high thermal conductive fibrous filler is oriented in an axial direction of the fixing member.   A fixing device using the fixing member according to claim 1.   An image forming apparatus using the fixing device according to claim 5.