JP2018165807A - Member for fixation and fixation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve an issue that the rubber of an elastic layer containing silicone rubber containing magnesium oxide is broken and is plastically deformed when the elastic layer is repeatedly compressed under a high-temperature environment if the rubber has a low hardness, and to provide a member for fixation having a low-hardness rubber layer containing magnesium oxide which is not easily broken by the repeated compressions under a high-temperature environment, using the characteristic of the rubber layer containing magnesium oxide that the rubber layer can have a large thermal capacity.SOLUTION: The member for fixation includes at least: a base material; and an elastic layer containing silicone rubber on the base material, the elastic layer including a silicone rubber and a filler dispersed in the silicone rubber and having a modulus of elasticity in the range between 0.10 MPa and 0.40 MPa, both inclusive, the filler containing magnesium oxide powders, and the magnesium oxide powders having a shape factor SF1 in the range of 100 to 120, both inclusive.SELECTED DRAWING: None

Description

  The present invention relates to a fixing member used in the field of fixing technology in an electrophotographic image forming apparatus such as a copying machine and a printer, and a fixing device including the fixing member.

  In general, in a heat fixing device used in an electrophotographic image forming apparatus such as a copying machine or a printer, a pair of heated rollers and rollers, a film and a roller, a belt and a roller, a belt and a belt, or the like are pressed against each other. . These rotating bodies are called fixing members.

  Then, the recording material holding the image formed by the unfixed toner is introduced into the press contact portion (fixing nip) formed between the rotating bodies, and the unfixed toner is heated together with the recording material. The heated toner is pressed against the recording material while being softened and melted, whereby the toner is fixed as an image on the recording material.

  A rotating body that is in direct contact with toner held on a recording material is called a fixing member, and is called a fixing roller, a fixing film, a fixing belt, or the like depending on the form. The rotating body pressed against the fixing member is referred to as a pressure member, and is referred to as a pressure roller, a pressure film, a pressure belt, or the like depending on the form.

  The fixing member has a structure in which a heat-resistant silicone rubber-containing elastic layer is disposed on a base formed of metal or a heat-resistant resin, and a fluororesin is coated or formed into a thin layer via an adhesive. Is generally known.

  When the silicone rubber-containing elastic layer has a low hardness, the fixing member having the above configuration uses the excellent flexibility to follow the unevenness of the paper fiber that is the recording material in the fixing nip, thereby softening the toner. There is an advantage that high-quality images can be obtained without causing uneven melting.

  Further, as a function of the fixing member, it is required to supply a sufficient amount of heat to soften and melt the recording material and the toner instantaneously at the fixing nip. In particular, when printing at high speed, it is necessary to increase the heat capacity of the fixing member and increase the amount of heat supplied to the recording material and the toner. From such a viewpoint, it is desired to increase the heat capacity of the silicone rubber-containing elastic layer.

  Furthermore, durability is required for the fixing member. In particular, in a region called a non-sheet passing portion where the recording material and the toner do not pass, the heat may not be taken away by the recording material and the toner, and the temperature may be as high as about 240 ° C. The low hardness silicone rubber-containing elastic layer is required to have durability against repeated compression deformation at the fixing nip in such a high temperature state.

  As a means for increasing the heat capacity of the silicone rubber-containing elastic layer, it is conceivable to include a filler having a large heat capacity in the elastic layer. Examples of the filler having a large heat capacity include magnesium oxide.

  Patent Document 1 discloses a fixing roll having a silicone rubber-containing rubber layer containing magnesium oxide and having a JIS A hardness of 75 ° or less.

JP-A-3-221982

According to the study by the present inventors, the rubber layer described in Patent Document 1 has a rubber hardness of, for example, JIS A hardness (JIS K6253), such as 15 °, and is soft at a high temperature. When repeatedly compressed, the elastic layer may be broken or plastically deformed.
Therefore, one aspect of the present invention is directed to providing a fixing member that includes magnesium oxide and includes a low-hardness rubber layer that is not easily broken or plastically deformed by repeated compression in a high temperature state.
Another aspect of the present invention is directed to providing a fixing device capable of stably forming a high-quality electrophotographic image.

According to one aspect of the present invention, there is provided a fixing member having a base and a silicone rubber-containing elastic layer on the base, wherein the elastic layer includes silicone rubber and a filler dispersed in the silicone rubber. The elastic layer has an elastic modulus of 0.10 MPa or more and 0.40 MPa or less, and the filler contains magnesium oxide powder, and the shape factor SF1 of the magnesium oxide powder is 100 or more, 120 The following fixing members are provided.
Furthermore, according to another aspect of the present invention, there is provided a fixing device including the fixing member.

It is explanatory drawing of the shape factor SF1 of magnesium oxide powder. It is explanatory drawing of the presumed mechanism regarding the effect of this invention. 2A is a schematic cross-sectional view of a fixing member according to the present invention in a belt form and FIG. It is a schematic diagram of an example for demonstrating the process of laminating | stacking a fluororesin surface layer. 1 is a schematic cross-sectional schematic diagram of an example of a fixing device including a fixing member of the present invention. It is a schematic perspective view of the jig | tool which evaluates the pressure | voltage resistance durability of the silicone rubber containing elastic layer concerning this invention.

  By dispersing magnesium oxide powder having a spherical or substantially spherical shape in the silicone rubber in the elastic layer, the present inventors have a low rubber hardness, and the rubber breaks and plastically deforms even when repeatedly compressed at high temperatures. I found something difficult to do.

The shape factor SF1 representing the deviation from the spherical shape of the magnesium oxide powder is expressed by the following equation using the maximum length Dmax at two points on the contour of the two-dimensional image of the particle and the particle area S of the two-dimensional image of the particle. .
SF1 = Dmax ² / S × π / 4 × 100

  SF1 is the closest to a sphere with 100 being the smallest, and the larger the value, the greater the deviation from the sphere (see FIG. 1). Since the shape of each magnesium oxide powder is different and has a distribution, SF1 is calculated using a value at which the cumulative frequency is 50% for each of the maximum length Dmax and the particle area S as representative values. . By blending a spherical rubber oxide powder having a shape factor SF1 of 100 or more and 120 or less into a silicone rubber-containing elastic layer, the rubber hardness is low and rubber is compressed even if it is repeatedly compressed at high temperatures. Was found to be difficult to break and plastically deform.

  The reason for this is that the more nearly spherical magnesium oxide powder makes it difficult for local stress to be applied to the surrounding silicone rubber, making it difficult for rubber destruction and plastic deformation near the interface between the powder and silicone rubber to occur. It is thought that it is from (see FIG. 2).

  The silicone rubber-containing elastic layer has an elastic modulus of 0.10 MPa or more and 0.40 MPa or less. An elastic layer having an elastic modulus in such a numerical range has excellent flexibility. For example, even when it is repeatedly compressed under a high temperature condition of 240 ° C., the elastic layer is effectively destroyed and plastically deformed. Can be suppressed.

  The silicone rubber-containing elastic layer may further include another filler different from the magnesium oxide powder. Magnesium oxide powder has a large heat capacity, but its thermal conductivity is not so high, and it is preferable to further contain other fillers for the purpose of increasing the thermal conductivity of the elastic layer. Specifically, graphite, metal silicon, silicon carbide, and alumina are exemplified, and it is preferable that at least one of these is further included.

  The content of all fillers in the silicone rubber-containing elastic layer (hereinafter also referred to as the total filler amount) is preferably 10% to 55% by volume. The total filler amount is preferably 55% or less by volume from the viewpoint of maintaining the elastic function of the silicone rubber-containing elastic layer as rubber. Moreover, it is preferable that the total filler amount be 10% or more by volume from the viewpoint of increasing the heat capacity of the silicone rubber-containing elastic layer.

  Moreover, it is preferable that the ratio for which a magnesium oxide accounts is more than 50 volume% and 95 volume% or less on the basis of all the fillers. When the proportion of magnesium oxide in the total filler exceeds 50% by volume, the filler occupying the most volume in the total filler is magnesium oxide. Therefore, by blending a silicone rubber-containing elastic layer with a shape of the magnesium oxide powder of the present invention close to a spherical shape, the rubber is low in hardness, and even when repeatedly compressed at a high temperature, the rubber is not easily destroyed or plastically deformed. Is preferable because it is easy to obtain. In addition, when the elastic layer contains magnesium oxide and further contains another filler, the proportion of magnesium oxide is preferably 95% by volume or less from the viewpoint of obtaining an effect of improving thermal conductivity by the other filler.

The heat capacity per unit volume of the silicone rubber-containing elastic layer is preferably 1.7 MJ / m ³ · K or more and 2.6 MJ / m ³ · K or less. Further, it is more preferably 2.0 MJ / m ³ · K or more and 2.6 MJ / m ³ · K or less. If only 55% magnesium oxide powder is contained in the silicone rubber by volume, the heat capacity per unit volume is 2.6 MJ / m ³ · K. In order to maintain the elastic function of the silicone rubber-containing elastic layer as a rubber, the filler content is preferably 55% or less, and the heat capacity is preferably 2.6 MJ / m ³ · K or less. Further, it is preferable that the heat capacity per unit volume is 1.7 MJ / m ³ · K or more from the viewpoint of increasing the heat capacity of the fixing member and increasing the heat supply amount to the recording material and the toner.

Hereinafter, the present invention will be described in detail.
(1) Outline of Configuration of Fixing Member Details of the present invention will be described with reference to the drawings.
FIGS. 3A and 3B are schematic cross-sectional views showing a fixing member according to the present invention. 3A shows an example of a fixing member in the form of a belt, and FIG. 3B shows an example of a fixing member in the form of a roller. The fixing member according to the present invention includes a base 1 and a silicone rubber-containing elastic layer 2 on the base 1. As shown in these drawings, the fixing member can have a surface layer 4 on the silicone rubber-containing elastic layer 2. Further, an adhesive layer 3 can be provided between the silicone rubber-containing elastic layer 2 and the surface layer 4. In this case, the surface layer 4 is fixed to the outer peripheral surface of the silicone rubber-containing elastic layer 2 by the adhesive layer 3.

(2) Base of fixing member When the fixing member has a belt shape as shown in FIG. 3A, a metal such as an electroformed nickel sleeve or a stainless sleeve, or a heat resistant resin such as polyimide is used for the base. be able to. On the outer surface of the substrate (the surface on the silicone rubber-containing elastic layer side), a layer for imparting a function of improving the adhesion to the elastic layer can be provided. That is, the silicone rubber-containing elastic layer only needs to be provided on the outer peripheral surface of the substrate, and another layer can be provided between the silicone rubber-containing elastic layer and the substrate. Further, a layer for imparting functions such as wear resistance and lubricity can be further provided on the inner surface of the substrate (the surface opposite to the outer surface).

  When the fixing member has a roller shape as shown in FIG. 3B, a cored bar made of a metal or an alloy such as aluminum or iron can be used for the base, and the fixing member can be used for heating and pressing. What is necessary is just to have the strength to endure. In FIG. 3B, a solid cored bar is used as the base, but a hollow cored bar may be used for the base, and a heat source such as a halogen lamp may be provided inside.

(3) Silicone rubber-containing elastic layer of fixing member The fixing member (fixing roller, fixing film, fixing belt, pressure roller, pressure film, pressure belt) of the present invention is either a fixing member or a pressure member. Either or both can be used. When the fixing member is used as the fixing member, the silicone rubber-containing elastic layer functions as a layer that imparts excellent flexibility for following the unevenness of the paper during fixing. Further, when the fixing member is used as the pressure member, the silicone rubber-containing elastic layer functions as a layer that imparts flexibility for securing the fixing nip. In order to express these functions in an environment where the temperature is about 240 ° C. in the non-sheet passing portion region, it is preferable to use silicone rubber for the elastic layer. Moreover, the silicone rubber containing elastic layer of this invention has an elasticity modulus of 0.10 MPa or more and 0.40 MPa or less as mentioned above.

  The silicone rubber-containing elastic layer can be formed by curing a liquid addition-curable silicone rubber composition. The liquid addition-curable silicone rubber composition includes at least a magnesium oxide powder having a shape factor SF1 of 100 or more and 120 or less and, for example, a liquid addition-curable silicone rubber component. That is, the silicone rubber-containing elastic layer can include at least a cured product of liquid addition-curable silicone rubber and magnesium oxide powder having a shape factor SF1 of 100 or more and 120 or less.

  The liquid addition-curable silicone rubber includes (a) an organopolysiloxane having an unsaturated aliphatic group, (b) an organopolysiloxane having an active hydrogen bonded to silicon as a crosslinking agent (c) a catalyst (for example, a platinum compound) ), And (d) a cure retardant.

(A) Organopolysiloxane having an unsaturated aliphatic group An organopolysiloxane having an unsaturated aliphatic group is an organopolysiloxane having an unsaturated aliphatic group such as a vinyl group (hereinafter sometimes referred to as component a). Any one can be used. For example, those represented by Structural Formula 1 and Structural Formula 2 below can be used as the component a.

・Ｒ^１Ｒ^１ＳｉＯで表わされる中間単位およびＲ^１Ｒ^２ＳｉＯで表わされる中間単位からなる群から選択されるいずれか一方または両方の中間単位と、Ｒ^１Ｒ^１Ｒ^１ＳｉＯ_１／２で表される分子末端とを有する直鎖状オルガノポリシロキサン（下記構造式２参照）

（構造式１と構造式２において、Ｒ^１はそれぞれ独立に不飽和脂肪族基を含まない非置換炭化水素基を表し、Ｒ^２はそれぞれ独立に不飽和脂肪族基を表し、ｍおよびｎは各々独立して０以上の整数を表す。） Either one or both intermediate units selected from the group consisting of an intermediate unit represented by R ¹ R ¹ SiO and an intermediate unit represented by R ¹ R ² SiO, and R ¹ R ¹ R ² SiO _1/2 Linear organopolysiloxane having molecular ends represented (see Structural Formula 1 below)

Either one or both intermediate units selected from the group consisting of an intermediate unit represented by R ¹ R ¹ SiO and an intermediate unit represented by R ¹ R ² SiO, and R ¹ R ¹ R ¹ SiO _1/2 Linear organopolysiloxane having molecular ends represented (see structural formula 2 below)

(In Structural Formula 1 and Structural Formula 2, R ¹ independently represents an unsubstituted hydrocarbon group that does not contain an unsaturated aliphatic group, R ² independently represents an unsaturated aliphatic group, and m and n are Each independently represents an integer of 0 or more.)

Examples of the unsubstituted hydrocarbon group containing no unsaturated aliphatic group bonded to a silicon atom and represented by R ¹ in Structural Formula 1 and Structural Formula 2 include the following. A methyl group, an ethyl group, a propyl group, an aryl group (for example, a phenyl group, etc.); Of these, a methyl group is preferred.

Examples of the unsaturated aliphatic group bonded to the silicon atom represented by R ² in Structural Formula 1 and Structural Formula 2 include a vinyl group, an allyl group, and a 3-butenyl group. A vinyl group is preferred.

  In the structural formula 1, a linear organosiloxane of n = 0 has unsaturated aliphatic groups only at both ends, and a linear organosiloxane of n = 1 or more is unsaturated at both ends and side chains. It has an aliphatic group. Moreover, the linear organosiloxane of Structural Formula 2 has an unsaturated aliphatic group only in the side chain. As the component a, one type may be used alone, or two or more types may be used in combination.

When the component a is used for the elastic layer of the fixing member, the viscosity is preferably 100 mm ² / s or more and 50,000 mm ² / s or less from the viewpoint of moldability.

(B) Organopolysiloxane having active hydrogen bonded to silicon (crosslinking agent)
An organopolysiloxane having active hydrogen bonded to silicon (hereinafter sometimes referred to as component b) is a crosslink that forms a crosslinked structure by reaction with an unsaturated aliphatic group in component a by the catalytic action of a platinum compound. It is an agent.

Any component can be used as the component b as long as it is an organopolysiloxane having a Si—H bond. For example, a component satisfying the following conditions can be suitably used. In addition, b component may be used individually by 1 type, and may use 2 or more types together.
-From the viewpoint of forming a crosslinked structure by reaction with an organopolysiloxane having an unsaturated aliphatic group, the average number of hydrogen atoms bonded to silicon atoms is 3 or more per molecule.
-Although the organic group couple | bonded with the silicon atom can illustrate the thing which is an unsubstituted hydrocarbon group which does not contain the unsaturated aliphatic group as mentioned above, for example, it is preferable that it is a methyl group.
The siloxane skeleton (—Si—O—Si—) may be linear, branched or cyclic.
-Si-H bonds may be present in any siloxane unit in the molecule.

（構造式３と構造式４において、Ｒ^１はそれぞれ独立に不飽和脂肪族基を含まない非置換炭化水素基を表し、ｐは０以上の整数を表し、ｑは１以上の整数を表す。）
なお、Ｒ^１は構造式１と構造式２で説明したとおり、不飽和脂肪族を含まない非置換炭化水素基であるが、メチル基であることが好ましい。 For example, linear organopolysiloxanes represented by the following structural formulas 3 and 4 can be used as the component b.

(In Structural Formula 3 and Structural Formula 4, R ¹ independently represents an unsubstituted hydrocarbon group not containing an unsaturated aliphatic group, p represents an integer of 0 or more, and q represents an integer of 1 or more. )
As described in Structural Formula 1 and Structural Formula 2, R ¹ is an unsubstituted hydrocarbon group that does not contain an unsaturated aliphatic group, and is preferably a methyl group.

(C) Catalyst As the hydrosilylation (addition curing) catalyst, for example, a platinum compound can be used. Specific examples include platinum carbonylcyclovinylmethylsiloxane complex and 1,3-divinyltetramethyldisiloxane platinum complex.

(D) Curing retarder In order to adjust the curing reaction rate of hydrosilylation (addition curing), what is called a curing retarder can be blended. Specific examples include 2-methyl-3-butyn-2-ol and 1-ethynyl-1-cyclohexanol.

  The elastic modulus of the silicone rubber-containing elastic layer can be adjusted to some extent depending on the types and blending amounts of the four components (a) to (d).

Magnesium oxide powder can be produced, for example, by the following method. Magnesium oxide powder can be obtained by refining and concentrating magnesium hydroxide produced by the reaction between seawater and lime, followed by dehydration, firing, and pulverization. Magnesium oxide powder has a heat capacity per unit volume of about 3.2 to 3.4 MJ / m ³ · K, and heat capacity per unit volume of alumina, which is often used to improve the thermal properties of silicone rubber-containing elastic layers. It is greater than about 3.0 MJ / m ³ · K. The thermal conductivity of magnesium oxide is about 45 to 60 W / m · K.

  Magnesium oxide powders having a shape factor SF1 of 100 or more and 120 or less used in the present invention are commercially available, for example, SL-WR manufactured by Kamijima Chemical Co., Ltd. and Pyroxma 5301K manufactured by Kyowa Chemical Industry Co., Ltd. it can.

As another filler used in the present invention, first, graphite can be mentioned. Graphite is also called graphite particles, and is classified into artificial graphite and natural graphite. As natural graphite, graphite produced by pulverization into fine particles can be used as graphite. Artificial graphite is obtained by pulverizing coke as a raw material, forming it into a rod shape, and graphitizing at a high temperature. The artificial graphite thus graphitized is then pulverized and classified, and the graphite can be used as graphite. In addition, the crystal structure of the carbon atom in graphite is a hexagonal plate crystal, and has a layered structure. One type of graphite may be used alone, or two or more types may be used in combination. The heat capacity per unit volume of graphite is as small as about 1.6 MJ / m ³ · K, but the thermal conductivity is as large as 100 to 250 W / m · K. By using magnesium oxide powder and graphite together, it contains silicone rubber. The thermal conductivity can be increased while increasing the heat capacity per unit volume of the elastic layer.

Examples of other fillers include metal silicon, silicon carbide, and alumina. The thermal conductivity of metallic silicon is about 150 W / m · K, and the heat capacity per unit volume is about 1.7 MJ / m ³ · K. The thermal conductivity of silicon carbide is about 270 W / m · K, and the heat capacity per unit volume is about 2.3 MJ / m ³ · K. The thermal conductivity of alumina is about 40 W / m · K, and the heat capacity per unit volume is about 3.0 MJ / m ³ · K as described above. These fillers do not have a heat capacity per unit volume that is equivalent to that of magnesium oxide, but when used in combination with magnesium oxide powder, the effect of increasing the thermal conductivity can be expected.

(4) Surface layer of fixing member As the surface layer, for example, a fluororesin layer, more specifically, a layer made of a resin exemplified below can be used. Examples of the fluororesin include tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer (PFA), polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), and the like. it can.

  Further, a filler may be contained in the surface layer for the purpose of improving thermophysical properties and wear resistance within a range not impairing moldability and toner releasability.

  The thickness of the surface layer (for example, the fluororesin layer) is preferably 10 μm or more and 100 μm or less. From the viewpoint of maintaining durability, the thickness of the surface layer is preferably 10 μm or more. Moreover, it is preferable that the thickness of a surface layer is 100 micrometers or less from a viewpoint of functioning the softness | flexibility of a silicone rubber containing elastic layer.

  The formation method of a surface layer is not specifically limited, For example, the following methods can be used. That is, a method in which a fluororesin molded into a tube shape is coated on a silicone rubber-containing elastic layer via an adhesive layer, or a fluororesin fine particle dispersed directly in a solvent or made into a paint A method of drying and heating and melting after coating on a rubber-containing elastic layer. Hereinafter, these methods will be described in more detail.

  The formation of the surface layer by the fluororesin tube coating will be described. By subjecting the inner surface of the fluororesin tube to sodium treatment, excimer laser treatment, ammonia treatment and the like in advance, the surface can be activated and the adhesion can be improved. FIG. 4 is a schematic view for explaining an example of a process of covering the silicone rubber-containing elastic layer 2 with the fluororesin tube 6 as a surface layer via the adhesive layer 5. Specifically, an adhesive is applied to the surface of the silicone rubber-containing elastic layer 2 to form the adhesive layer 5. The adhesive will be described later. The outer surface of the adhesive layer 5 is covered with a fluororesin tube as a surface layer and laminated.

  As the adhesive, it is preferable to use an addition-curable silicone rubber containing a self-adhesive component. Specifically, the silicone rubber contains an organopolysiloxane having a plurality of unsaturated aliphatic groups represented by vinyl groups in the molecular chain, a hydrogenorganopolysiloxane, and a platinum compound as a crosslinking reaction catalyst. Can be used. This silicone rubber is cured by an addition reaction. As the adhesive made of such an addition-curable silicone rubber, a known adhesive can be used.

  It is not necessary when the base 1 is a core metal capable of maintaining its shape, but when using a thin base such as a resin belt or metal sleeve used for a belt-shaped fixing member, deformation during processing is not necessary. In order to prevent this, it is preferable to hold the base 1 by fitting it around the core. The coating method of the fluororesin tube is not particularly limited, and a method of coating an adhesive as a lubricant, a method of expanding and coating the fluororesin tube from the outside, and the like can be used. After the coating, the surplus adhesive remaining between the silicone rubber-containing elastic layer 2 and the fluororesin tube 6 can be removed by using a means (not shown). The thickness of the adhesive layer 5 after being handled is preferably 20 μm or less. If the thickness of the adhesive layer is 20 μm or less, it is easy to suppress an increase in the hardness of the fixing member, and when used as a fixing member, it has excellent followability to paper irregularities, and when used as a pressure member, fixing. It is easy to obtain a good fixed image without narrowing the nip width. Next, the adhesive layer is cured by heating with a heating means such as an electric furnace for a predetermined time, and both ends are processed to a desired length as necessary, thereby fixing the fixing member of the present invention. Can be obtained.

  The formation of the surface layer by fluororesin coating will be described. For the fluororesin coating process for forming the surface layer, a method such as electrostatic coating of fluororesin fine particles or spray coating of fluororesin paint can be used. When using the electrostatic coating method, first apply electrostatic coating of fluororesin fine particles to the inner surface of the mold, and heat the mold to the melting point or higher of the fluororesin, thereby forming a thin film of fluororesin on the inner surface of the mold. Form. After that, the base is inserted after the inner surface is bonded. Subsequently, a liquid addition curable silicone rubber composition containing at least a magnesium oxide powder having a shape factor SF1 of 100 or more and 120 or less and a liquid addition curable silicone rubber component, for example, between the substrate and the fluororesin. inject. The fixing member of the present invention can be obtained by curing the injected liquid addition curable silicone rubber composition and then removing the mold.

(5) Manufacturing Method of Fixing Member The manufacturing method of the fixing member of the present invention includes, for example, the following silicone rubber-containing elastic layer forming step. A step of forming a silicone rubber-containing elastic layer by applying a liquid addition-curable silicone rubber composition on the outer peripheral surface of a substrate and heating and curing the composition.

  Moreover, the manufacturing method of this invention can also include the process of preparing the liquid addition-curable silicone rubber composition containing the following 4 components of (a) to (d). (A) Organopolysiloxane having an unsaturated aliphatic group. (B) Organopolysiloxane having active hydrogen bonded to silicon as a crosslinking agent. (C) Catalyst (for example, platinum compound). (D) Magnesium oxide powder having a curing retarder and a shape factor SF1 of 100 or more and 120 or less. A step of laminating a surface layer (for example, a fluororesin surface layer) on the silicone rubber-containing elastic layer.

  In addition, in the manufacturing method of this invention, the order of each process can be set suitably, and these processes can also be performed simultaneously (in parallel). When the silicone rubber-containing elastic layer and the surface layer are formed, the above-described methods for forming the silicone rubber-containing elastic layer and the surface layer can be used.

(6) Fixing device provided with fixing member of the present invention The fixing device of the present invention will be described. The fixing device of the present invention is a fixing device used in an electrophotographic image forming apparatus, and includes the fixing member of the present invention as a fixing belt or a fixing roller and / or a pressure belt or a pressure roller. . The electrophotographic image forming apparatus includes a photosensitive member, a latent image forming unit, a unit for developing the formed latent image with toner, a unit for transferring the developed toner image to a recording material, and fixing the toner image on the recording material. An electrophotographic image forming apparatus having means and the like can be mentioned.

  FIG. 5 shows a schematic configuration diagram of an example of the fixing device of the present invention. In FIG. 5, reference numeral 7 denotes an endless belt-like fixing belt, which is inscribed with respect to the belt guide member 8 and the stay 9 with a margin in circumference. 10 is a heating body, and an electric resistance material such as silver palladium (Ag / Pd), which generates heat when current flows on a heating body substrate made of alumina, ceramic, or the like, is applied in a linear or belt shape by screen printing or the like. There are layers. Further, a glass coating layer having a thickness of about 10 μm is sequentially formed thereon in order to ensure the protection and insulation of the electric resistance material. Further, a thermistor is in contact with the back surface of the heating body substrate, and the surface temperature of the fixing belt 7 is maintained at a temperature at which fixing can be performed by controlling the power to the electric resistance material according to the temperature detected by the thermistor. Can do.

  The pressure roller 11 is in pressure contact with the heating body via the fixing belt 7 and is rotationally driven by a pressure roller driving unit. The pressure roller 11 is driven to rotate, and the fixing belt 7 is rotated following the pressure roller 11. A recording material such as paper on which an unfixed image is formed is nipped and conveyed between the fixing belt 7 and the pressure roller 11 so that the unfixed image is heated and fixed to the recording material. This fixing device is a relatively low pressure type fixing device.

  Here, the fixing device of the fixing belt and the pressure roller is taken as an example, but the fixing device of the present invention uses the fixing member of the present invention as the fixing belt or the fixing roller and / or the pressure belt or the pressure roller. As long as it is included, and is not limited to that shown in FIG.

Hereinafter, the present invention will be described in more detail with reference to examples.
First, a method for calculating the shape factor SF1 of the magnesium oxide powder will be described. First, an aqueous dispersion of magnesium oxide powder is prepared. Specifically, put about 1/4 to 1/3 of magnesium oxide in a 50 cc glass bottle, add pure water so that the volume combined with magnesium oxide is about 80%, and add a small amount of surfactant. After adding and stirring well, an aqueous dispersion of magnesium oxide was prepared. About this solution, the image pickup of the particle | grains was performed 5 times on condition of the following with the flow type particle shape analyzer (FPIA-3000, Sysmex Corporation make). Measurement mode: HPF, counting method: quantitative counting, sheath liquid: particle sheath, stirring mode: yes, objective lens: 10 times, optical system: bright field, total count: 36000, number of repeated measurements: once. This device introduces a particle suspension into a transparent flow cell to form a flat sample flow, and irradiates the flat flow with pulsed light to pick up a particle image. Thus, information on the size and shape of the particles can be obtained. The image analysis of the particle | grains was performed about each time measured 5 times (HPF pixel size: 0.37 micrometer, BG compensation: Yes, Smoothing filter: Median, Edge emphasis level: 2D filter). SF1 is calculated from the following equation using, as representative values, the maximum frequency Dmax at two points on the contour of the two-dimensional image obtained as a result and the particle area S of the particle two-dimensional image having a cumulative frequency of 50%. The average value was calculated.
SF1 = Dmax ² / S × π / 4 × 100
The same SF1 value can be obtained by heating the silicone rubber-containing elastic layer of the fixing member to a high temperature, decomposing and removing the silicone component, separating the magnesium oxide, and analyzing the separated magnesium oxide in the same manner. It is done.

[Example 1]
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder Firstly, the component a has vinyl groups that are unsaturated aliphatic groups only at both ends of the molecular chain, and other unsaturated aliphatic groups. 100 parts by mass of a silicone polymer having a methyl group as an unsubstituted hydrocarbon group not contained (viscosity 10,000 mm ² / s, hereinafter referred to as “Vi”) was prepared.
Next, 240.5 parts by mass of magnesium oxide powder (trade name: Pyroxuma 5301K, shape factor SF1: 108, manufactured by Kyowa Chemical Industry Co., Ltd.) was weighed and added to Vi.
Next, 0.1 part by mass of 1-ethynyl-1-cyclohexanol (manufactured by Tokyo Chemical Industry Co., Ltd.), which is a curing retarder, was added to the mixture of Vi and magnesium oxide powder as the d component.
Next, 0.1 part by mass of a hydrosilylation catalyst was added as a component c into the mixture of Vi, magnesium oxide powder and a curing retarder. The hydrosilylation catalyst used is a mixture of platinum catalyst: 1,3-divinyltetramethyldisiloxane complex, 1,3-divinyltetramethyldisiloxane, and 2-propanol.
Further, 2.0 parts by mass of a silicone polymer having a linear siloxane skeleton as a component b and having an active hydrogen group bonded to silicon only in the side chain (viscosity 30 mm ² / s, hereinafter referred to as “SiH”) did. Thereafter, a light weight silicone polymer is added to a mixture of Vi, magnesium oxide powder, curing retarder and platinum catalyst, and mixed thoroughly to form a liquid addition curable silicone rubber composition containing 40% by volume of magnesium oxide powder. I got a thing.

(2) Preparation of fixing belt Next, a fixing belt was prepared as follows using the liquid addition-curable silicone rubber composition containing the obtained magnesium oxide powder.
A nickel electroformed endless sleeve having an inner diameter of 30 mm, a width of 400 mm, and a thickness of 40 μm was prepared as a substrate. During a series of manufacturing processes, the endless sleeve (endless sleeve) was handled with a core inserted therein.
First, a primer (trade name: DY39-051 A / B, manufactured by Toray Dow Corning Co., Ltd.) was applied almost uniformly on the outer peripheral surface of the substrate, and after drying the solvent, the substrate was dried in an electric furnace at 160 ° C. for 30 minutes. The baking process was performed.
On the primer-treated substrate, the liquid addition-curable silicone rubber composition containing the magnesium oxide powder was applied by a ring coating method with a thickness of 300 μm. The endless belt to which the silicone rubber composition was applied was heated in an electric furnace at 160 ° C. for 1 minute (primary curing). Then, it was heated in an electric furnace at 200 ° C. for 4 hours (secondary curing) to cure the silicone rubber composition, thereby forming a silicone rubber-containing elastic layer containing magnesium oxide powder.

  Next, while rotating the surface of the obtained endless belt at a moving speed of 20 mm / sec in the circumferential direction, using an ultraviolet lamp installed at a distance of 10 mm from the surface, the surface of the silicone rubber containing magnesium oxide powder is Ultraviolet irradiation was performed. As the ultraviolet lamp, a low-pressure mercury ultraviolet lamp (trade name: GLQ500US / 11, manufactured by Toshiba Lighting & Technology Co., Ltd. (formerly Harrison Toshiba Lighting Co., Ltd.)) was used for irradiation for 6 minutes at room temperature in an air atmosphere.

Next, an addition-curable silicone rubber adhesive (trade name: SE1819CV A / B, manufactured by Toray Dow Corning Co., Ltd.) was applied to the surface of the elastic layer of the endless belt substantially uniformly so as to have a thickness of 20 μm. .
Next, a fluororesin tube (trade name: KURANFLON-LT, manufactured by Kurashiki Boseki Co., Ltd.) having an inner diameter of 29 mm and a thickness of 30 μm was laminated on the adhesive. After that, by handling the belt uniformly from above the fluororesin tube, excess adhesive was handled from between the elastic layer and the fluororesin tube so as to be sufficiently thin.
The obtained endless belt was heated in an electric furnace at 200 ° C. for 1 hour to cure the adhesive and fix the surface layer made of the fluororesin tube on the elastic layer. Both ends of the obtained endless belt were cut to obtain a fixing belt having a width of 341 mm.

(3) Characteristic Evaluation of Fixing Belt Elastic Layer First, a primer treatment was performed on the substrate by the same method as the above-described fixing belt manufacturing method, and then an elastic layer (elasticity after secondary curing was formed by a ring coat method). Layer).

(3-1) Tensile Elastic Modulus of Elastic Layer In order to confirm that the elastic layer has low hardness, the tensile elastic modulus of the elastic layer was measured.
Specifically, the elastic layer was cut out with a punching die (JIS No. 3 dumbbell type), and the rubber thickness in the vicinity of the center as the measurement location was measured. Next, the cut out elastic layer was tested at a tensile speed of 500 mm / min and room temperature using a tensile tester (device name: Strograph EII-L1, manufactured by Toyo Seiki Seisakusho Co., Ltd.). The tensile modulus is the slope when the measured data is linearly approximated in the range of 0 to 100% of strain, with the horizontal axis representing the sample strain and the vertical axis representing the tensile stress. .
As a result, the tensile elastic modulus of the elastic layer was 0.25 MPa.

(3-2) Heat capacity per unit volume of elastic layer The heat capacity C _V per unit volume was calculated from the following equation.
C _V = C _P × ρ
In the formula, _Cp is constant pressure specific heat (J / (kg · K)), and ρ is density (kg / m ³ ).
Here, the values of the constant pressure specific heat and density were determined by the following method.

- constant pressure specific heat _{C P}
The constant-pressure specific heat of the elastic layer was measured using a differential scanning calorimeter (trade name: DSC823e, manufactured by METTLER TOLEDO).

Specifically, an aluminum pan was used as a sample pan and a reference pan. First, as a blank measurement, after keeping both pans empty for 10 minutes at a constant temperature of 15 ° C., the temperature was increased to 215 ° C. at a temperature increase rate of 10 ° C./min, and further for 10 minutes at 215 ° C. Measurements were carried out with a program kept at a constant temperature. Next, 10 mg of synthetic sapphire having a known constant pressure specific heat was used as a reference material, and measurement was performed using the same program. Next, a 10 mg measurement sample of the same amount as the reference sapphire was cut out from the elastic layer portion, set in a sample pan, and measured with the same program. These measurement results were analyzed using the specific heat analysis software provided with the differential scanning calorimeter, from the average value of five measurements was calculated constant pressure specific heat C _P at 25 ° C..
As a result, the constant-pressure specific heat of the silicone rubber-containing elastic layer was 1.16 J / (g · K).

・ Density ρ
The density of the elastic layer was measured using a dry automatic densimeter (trade name: Accupic 1330-01, manufactured by Shimadzu Corporation).
Specifically, using a 10 cm ³ sample cell, the sample was cut from the elastic layer so as to satisfy approximately 80% of the cell volume, and the mass of this sample was measured, and then placed in the sample cell.
This sample cell was set in a measurement unit in the apparatus, and helium was used as a measurement gas. After gas replacement, volume measurement was performed 10 times. The density of the sample was calculated from the sample mass and the measured volume for each round, and the average value was obtained.
As a result, the density of the elastic layer containing silicone rubber was 1.98 g / cm ³ .
In this way, the result of calculating the specific heat at constant pressure C _P and the density ρ per unit volume heat capacity C _V of the silicone rubber-containing elastic layer obtained was 2.3MJ / m ³ · K.

(3-3) Thermal conductivity in the thickness direction of the elastic layer The thermal conductivity λ in the thickness direction of the elastic layer was calculated from the following equation.
λ = α × C _p × ρ
Where λ is the thermal conductivity in the thickness direction of the elastic layer (W / (m · K)), α is the thermal diffusivity in the thickness direction (m ² / s), and C _p is the constant pressure specific heat (J / (kg · K)), ρ is density (kg / m ³ )
Here, regarding the constant-pressure specific heat _Cp and density ρ of the elastic layer, the values obtained by the above-described method were converted into units. The value of the thermal diffusivity in the thickness direction was determined by the following method.

・ Thermal diffusivity α
The thermal diffusivity in the thickness direction of the elastic layer was measured at room temperature (25 ° C.) using a periodic heating method thermophysical property measuring apparatus (trade name: FTC-1, manufactured by ULVAC-RIKO Co., Ltd.). As for the samples, the elastic layer was cut into a sample piece having an area of 8 mm × 12 mm with a cutter to prepare a total of five samples, and the thickness of each sample was measured. Next, each sample was measured a total of 5 times, and the average value (m ² / s) was obtained.

From the constant pressure specific heat C _p (J / (kg · K)) and density ρ (kg / m ³ ) of the elastic layer converted in units, and the measured thermal diffusivity α (m ² / s), As a result of calculating the thermal conductivity λ, it was 0.8 W / (m · K).

(4) Evaluation of pressure-resistant durability of the fixing belt elastic layer First, after a primer treatment is performed on a 50 mm × 50 mm stainless steel plate (reference numeral 12 in FIG. 6), an elastic layer having a thickness of 1 mm is formed by press molding using a mold. (Elastic layer after secondary curing) was formed.
With respect to these four elastic layers, the pressure durability was evaluated using the jig shown in FIG. The evaluation conditions were a sample surface temperature of 240 ° C. and a load of 15 N, and a pressing roller (width: 10 mm, diameter: 15 mm) of reference number 13 was reciprocated to the left and right to evaluate the average value of the time for rubber to break or plastically deform.
As a result, it was found that even after 600 minutes, no rubber breakage or plastic deformation was observed, and the pressure durability was very excellent.

(5) Evaluation of fixing belt The fixing belt obtained by the method described in (2) above was incorporated into a fixing device of an office multifunction device (trade name: imageRUNNER ADVANCE C5051, manufactured by Canon Inc.).
This fixing device was mounted on the above-mentioned multifunction peripheral. Using this multi-function machine, the paper passing durability was evaluated using plain paper. The sheet passing durability was considered good when 300,000 sheets could be passed without the destruction or plastic deformation of the silicone rubber-containing elastic layer in the non-sheet passing portion of the fixing belt. The image quality was evaluated by visual observation of the fixed image from the viewpoint of uneven gloss. As a result, even when 300,000 sheets were passed, the silicone rubber-containing elastic layer was not broken or plastically deformed in the non-sheet passing portion of the fixing belt, the paper passing durability was good, and the image quality was excellent.

[Example 2]
(1) Preparation of Liquid Addition-Cure Silicone Rubber Composition Containing Magnesium Oxide Powder Magnesium oxide powder (trade name: SL-WR, shape factor SF1: 107, manufactured by Kamishima Chemical Co., Ltd.) and Example 1 1.44 parts by mass of the same b component was used. Otherwise in the same manner as in Example 1, a liquid addition-curable silicone rubber composition containing 40% by volume of magnesium oxide powder was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.18 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.3 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 0.8 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 500 minutes, rubber breakage and plastic deformation were observed, but the pressure durability was excellent.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 3
(1) Preparation of liquid addition-curable silicone rubber composition containing magnesium oxide powder 441 parts by mass of magnesium oxide powder (trade name: Pyroxuma 5301K, shape factor SF1: 108, manufactured by Kyowa Chemical Industry Co., Ltd.) An appropriate amount of the same component b as in Example 1 was used in addition to Vi. Otherwise in the same manner as in Example 1, a liquid addition-curable silicone rubber composition containing 55% by volume of magnesium oxide powder was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.12 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.6 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 100 minutes, rubber breakage and plastic deformation were observed, but the pressure durability was good.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 4
(1) Preparation of liquid addition-curable silicone rubber composition containing magnesium oxide powder 40 parts by mass of magnesium oxide powder (trade name: Pyroxuma 5301K, shape factor SF1: 108, manufactured by Kyowa Chemical Industry Co., Ltd.) and Vi And an appropriate amount of the same component b as in Example 1 was used. Otherwise in the same manner as in Example 1, a liquid addition-curable silicone rubber composition containing 10% by volume of magnesium oxide powder was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.35 MPa
(3-2) Heat capacity per unit volume of elastic layer 1.7 MJ / m ³ · K
(3-3) Thermal conductivity in thickness direction of elastic layer 0.3 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 600 minutes, no rubber breakage or plastic deformation was observed, indicating that the pressure resistance durability was excellent.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 5
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder First, 100 parts by mass of the same component a as in Example 1 was prepared.
Next, 201.9 parts by mass of magnesium oxide powder (trade name: Pyroxuma 5301K, shape factor SF1: 108, manufactured by Kyowa Chemical Industry Co., Ltd.) was weighed and added to Vi.
Next, 31.3 parts by mass of graphite (trade name: Nikabeads P10B-AZ, manufactured by Nippon Carbon Co., Ltd.) was weighed and added to the mixture of Vi and magnesium oxide powder.
Next, 0.1 part by mass of the same d component as in Example 1 was added to the mixture of Vi, magnesium oxide powder and graphite.
Next, 0.1 part by mass of the same component c as in Example 1 was added to the mixture of Vi, magnesium oxide powder, graphite, and cure retarder.
Further, the same component b as in Example 1 was used in an appropriate amount and added to a mixture of Vi, magnesium oxide powder, graphite, curing retarder, and platinum catalyst. Thereafter, by mixing thoroughly, a liquid addition-curable silicone rubber composition containing 33% by volume of magnesium oxide powder and 8% by volume of graphite was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.21 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 200 minutes, rubber breakage and plastic deformation were observed, but it was found that the pressure durability was good.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 6
(1) Preparation of Liquid Addition-Cure Silicone Rubber Composition Containing Magnesium Oxide Powder Magnesium oxide powder (trade name: SL-WR, shape factor SF1: 107, manufactured by Kamishima Chemical Co., Ltd.) and Example 1 The same b component was used at 1.37 parts by mass. Otherwise in the same manner as in Example 5, a liquid addition-curable silicone rubber composition containing 33% by volume of magnesium oxide powder and 8% by volume of graphite was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.22 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 140 minutes, rubber breakage and plastic deformation were observed, but it was found that the pressure durability was good.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 7
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder Firstly, the component a has vinyl groups which are unsaturated aliphatic groups at both ends and side chains of the molecular chain, and other unsaturated aliphatic groups. 100 parts by mass of a silicone polymer having a methyl group as an unsubstituted hydrocarbon group not containing a group (viscosity 20,000 mm ² / s, hereinafter referred to as “Vi-2”) was prepared.
Next, 1.21 parts by mass of magnesium oxide powder (trade name: SL-WR, shape factor SF1: 107, manufactured by Kamishima Chemical Co., Ltd.) and the same component b as in Example 1 were used. Otherwise in the same manner as in Example 5, a liquid addition-curable silicone rubber composition containing 33% by volume of magnesium oxide powder and 8% by volume of graphite was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.13 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 150 minutes, rubber breakage and plastic deformation were observed, but it was found that the pressure durability was good.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 8
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder In the same manner as in Example 6, except that an appropriate amount of the same component b as in Example 1 is used, 33% by volume of magnesium oxide powder is blended. A liquid addition curable silicone rubber composition containing 8% by volume of graphite was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.38 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure endurance of the fixing belt elastic layer After 400 minutes, rubber breakage and plastic deformation were observed, but it was found to be excellent in pressure endurance.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

Example 9
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder First, 100 parts by mass of the same component a as in Example 1 was prepared. Subsequently, two types of magnesium oxide powders (trade name: Pyroxuma 5301K, shape factor SF1: 108, manufactured by Kyowa Chemical Industry Co., Ltd., and product names: RF-10C-FC, shape factor SF1: 150, Ube Materials Corporation Made). The two types of magnesium oxide powders were used in a blending ratio such that the total amount was 240.5 parts by mass and the shape factor SF1 was 118. Further, an appropriate amount of the same component b as in Example 1 was used. Otherwise in the same manner as in Example 1, a liquid addition-curable silicone rubber composition containing 40% by volume of magnesium oxide powder was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.19 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.3 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 0.9 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer Although rubber breakage and plastic deformation were observed after 100 minutes, the pressure durability was found to be good.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, even when 300,000 sheets were passed, no breakage or plastic deformation of the silicone rubber-containing elastic layer was observed in the non-sheet passing portion of the fixing belt. The paper durability was good and the image quality was excellent.

[Comparative Example 1]
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder First, 100 parts by mass of the same component a as in Example 1 was prepared. Subsequently, two types of magnesium oxide powders (trade name: Pyroxuma 5301K, shape factor SF1: 108, manufactured by Kyowa Chemical Industry Co., Ltd., and product names: RF-10C-FC, shape factor SF1: 150, Ube Materials Corporation Made). The two kinds of magnesium oxide powders were used at a blending ratio such that the total amount was 240.5 parts by mass and the shape factor SF1 was 123. Otherwise in the same manner as in Example 9, a liquid addition-curable silicone rubber composition containing 40% by volume of magnesium oxide powder was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.20 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.3 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 0.9 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 90 minutes, rubber breakdown and plastic deformation were observed, indicating that the pressure durability was somewhat inferior.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, the image quality is excellent. However, after passing 250,000 sheets, the elastic layer containing silicone rubber is broken or plastically deformed in the non-sheet passing portion of the fixing belt. As a result, it was found that the paper passing durability was insufficient.

[Comparative Example 2]
(1) Preparation of Liquid Addition-Cure Silicone Rubber Composition Containing Magnesium Oxide Powder Magnesium oxide powder (trade name: RF-10C-FC, shape factor SF1: 150, manufactured by Ube Materials Co., Ltd.) and Examples The same b component as 1 was used at 1.28 parts by mass. Otherwise in the same manner as in Example 1, a liquid addition-curable silicone rubber composition containing 40% by volume of magnesium oxide powder was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.20 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.3 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 30 minutes, rubber breakdown and plastic deformation were observed, and it was found that the pressure durability was inferior.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, the image quality is excellent. However, after passing 70,000 sheets, the elastic layer containing silicone rubber is broken or plastically deformed in the non-sheet passing portion of the fixing belt. As a result, it was found that the paper passing durability was insufficient.

[Comparative Example 3]
(1) Preparation of Liquid Addition-Cure Silicone Rubber Composition Containing Magnesium Oxide Powder Magnesium oxide powder (trade name: RF-10C-FC, shape factor SF1: 150, manufactured by Ube Materials Co., Ltd.) and implementation 1.37 parts by mass of the same component b as in Example 1 was used. Otherwise in the same manner as in Example 5, a liquid addition-curable silicone rubber composition containing 33% by volume of magnesium oxide powder and 8% by volume of graphite was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.23 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.2 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 70 minutes, the rubber was broken and plastically deformed, and it was found that the pressure durability was slightly inferior.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, the image quality is excellent. However, after passing 150,000 sheets, the silicone rubber-containing elastic layer was broken or plastically deformed in the non-sheet passing portion of the fixing belt. It was recognized and the durability was found to be slightly insufficient.

[Comparative Example 4]
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder Magnesium oxide powder 33 is the same as in Example 6 except that 1.22 parts by mass of the same component b as in Example 1 is used. A liquid addition-curable silicone rubber composition containing a volume percent and a graphite volume of 8 percent was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.08 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure durability of the fixing belt elastic layer After 40 minutes, the rubber was broken and plastically deformed, and it was found that the pressure durability was inferior.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, the image quality was excellent. However, after passing 90,000 sheets, the elastic layer containing silicone rubber was broken or plastically deformed in the non-sheet passing portion of the fixing belt. It was recognized and the durability was found to be insufficient.

[Comparative Example 5]
(1) Preparation of Liquid Addition-Curable Silicone Rubber Composition Containing Magnesium Oxide Powder In the same manner as in Example 6, except that an appropriate amount of the same component b as in Example 1 is used, 33% by volume of magnesium oxide powder is blended. A liquid addition curable silicone rubber composition containing 8% by volume of graphite was obtained.
(2) Preparation of fixing belt A fixing belt was prepared in the same manner as in Example 1 except that the liquid addition-curable silicone rubber composition obtained above was used.
(3) Evaluation of characteristics of fixing belt elastic layer The results of evaluation similar to Example 1 are shown below.
(3-1) Tensile modulus of elastic layer 0.43 MPa
(3-2) Heat capacity per unit volume of elastic layer 2.1 MJ / m ³ · K
(3-3) Thermal conductivity in the thickness direction of the elastic layer 1.0 W / (m · K)
(4) Evaluation of pressure-resistant durability of the fixing belt elastic layer After 500 minutes, rubber breakage and plastic deformation were observed, but it was found that the pressure-resistant durability was excellent.
(5) Evaluation of fixing belt As a result of evaluation in the same manner as in Example 1, the silicone rubber-containing elastic layer was not broken or plastically deformed in the non-sheet passing portion of the fixing belt after passing 300,000 sheets, and the durability was It was good. However, even in the early stage of durability, the elastic modulus of the silicone rubber-containing elastic layer was high, that is, the hardness was high, and thus image gloss unevenness considered to be caused by toner softening / melting unevenness was recognized, and the image quality was inferior.

〔Evaluation results〕
Hereinafter, the evaluation results of Examples and Comparative Examples shown in Table 1 will be described. In Examples 1 to 9, the elastic modulus of the silicone rubber-containing elastic layer is 0.10 MPa or more and 0.40 MPa or less (about 15 ° or less in JIS A hardness (JIS K6253)), and is excellent in flexibility. Furthermore, it can be seen from the image quality evaluation result of the fixing belt that it follows the unevenness of the paper fiber as the recording material in the fixing nip, and that toner softening / melting unevenness hardly occurs and a high quality image can be obtained. The silicone rubber-containing elastic layer contained magnesium oxide powder having a shape factor SF1 of 100 or more and 120 or less, and the pressure resistance of the elastic layer was good at 100 minutes or more. In addition, as a result of evaluating the passing performance of the fixing belt, even when 300,000 sheets are passed, the elastic layer containing the silicone rubber is not broken or plastically deformed in the non-passing portion of the fixing belt, and the passing durability is good. I found out.

  On the other hand, in Comparative Examples 1 to 3, the shape factor SF1 of the magnesium oxide powder contained in the silicone rubber-containing elastic layer exceeds 120. Therefore, the pressure durability of the elastic layer was less than 100 minutes. In addition, as a result of evaluating the sheet passing durability of the fixing belt, it was found that the silicone rubber-containing elastic layer was broken or plastically deformed in the non-sheet passing portion of the fixing belt with less than 300,000 sheets, and the durability was insufficient. . Comparative Example 4 is a silicone rubber-containing elastic layer containing magnesium oxide powder having an elastic modulus of the silicone rubber-containing elastic layer of less than 0.10 MPa and a shape factor SF1 of 100 or more and 120 or less. However, the pressure resistance of the elastic layer was 40 minutes and less than 100 minutes. In addition, as a result of evaluating the sheet passing durability of the fixing belt, it was found that the non-sheet passing portion of the fixing belt after the passing of 90,000 sheets showed breakage and plastic deformation of the silicone rubber-containing elastic layer, and the sheet passing durability was poor. . In Comparative Example 5, the pressure resistance durability is excellent, but the elastic modulus of the silicone rubber-containing elastic layer exceeds 0.40 MPa, and the flexibility is poor. Therefore, it was found that the fixing belt could not follow the irregularities caused by the paper fibers as the recording material, and the image gloss unevenness considered to be caused by the softening and melting unevenness of the toner was recognized, and the image quality was inferior to the others.

1 substrate 2 elastic layer containing silicone rubber 3 adhesive layer 4 surface layer 5 adhesive layer 6 fluororesin tube 7 fixing belt 8 belt guide member 9 stay 10 heating element 11 pressure roller 12 stainless steel plate 13 pressing roller

Claims (4)

A fixing member having a base and a silicone rubber-containing elastic layer on the base,
The elastic layer is
Silicone rubber, and
A filler dispersed in the silicone rubber,
The elastic layer has an elastic modulus of 0.10 MPa or more and 0.40 MPa or less, and
The fixing member is characterized in that the filler contains magnesium oxide powder, and the magnesium oxide powder has a shape factor SF1 of 100 or more and 120 or less.   The elastic layer further includes another filler different from the magnesium oxide powder, and the other filler is at least one selected from the group consisting of graphite, metal silicon, silicon carbide, and alumina, and the elastic layer The content of all fillers in the layer is 10% or more and 55% or less by volume, and the proportion of magnesium oxide based on all fillers is more than 50% by volume and 95% by volume or less. Item 2. The fixing member according to Item 1. The fixing member according to claim 1, wherein a heat capacity per unit volume of the elastic layer is 1.7 MJ / m ³ · K or more and 2.6 MJ / m ³ · K or less.   A fixing device comprising the fixing member according to claim 1.

Images