JP5019366B2 - Manufacturing method of fixing roller - Google Patents

Description

  The present invention relates to a fixing roller used in a toner image fixing unit of an electrophotographic image forming apparatus such as a copying machine, a facsimile machine, and a laser beam printer, and a manufacturing method thereof, and more particularly, to an elastic layer made of a porous silicone elastomer. The present invention relates to a fixing roller having a fluororesin tube provided on the outside thereof and a method for manufacturing the same.

  A fixing roller having an elastic layer made of a porous silicone elastomer used for a toner image fixing unit of an electrophotographic image forming apparatus is known in many patent documents. As a silicone elastomer porous body provided in such a fixing roller, a closed-cell porous body has been conventionally produced mainly utilizing a foaming phenomenon. However, in the method for producing a silicone elastomer porous body utilizing the foaming phenomenon, the silicone rubber is cured and foamed at the same time, so the size of the cells (pores) in the resulting porous body is non-uniform, Not only does the size of the cells vary, but it is difficult to form cells with a fine size of, for example, 50 μm or less. Also, the silicone elastomer porous body manufactured using a foaming agent has a large cell size and non-uniformity, so the shape during heating is not stable and the force is evenly distributed when torque is applied. There is a problem that it cannot be made to break and is easy to break. In addition, some porous bodies manufactured by utilizing the foaming phenomenon have an open-cell type, but have a problem that the strength is weaker than that of the closed-cell type and the glass is easily broken.

  On the other hand, in Patent Document 1 and Patent Document 2, a liquid silicone rubber material that is cured to produce a silicone elastomer, an emulsifier, and a water-in-oil emulsion composition containing water are applied to the outer periphery of the roller shaft. It is disclosed that an elastic layer made of a porous material is formed by volatilizing water by heating. In the methods of Patent Document 1 and Patent Document 2, the porous body obtained is made of non-foamed closed cells generated without foaming phenomenon, and therefore a silicone elastomer porous body having uniform fine cells (pores) It is possible to form an elastic layer made of and excellent in mechanical strength.

However, since the non-foamed porous body disclosed in Patent Document 1 and Patent Document 2 is a closed-cell type, water is not easily removed, and water vapor is removed when water is removed by secondary heating. It has been found by the present inventors that they are often damaged by pressure. In particular, for example, in a fixing roller of a type in which the outer periphery of a porous body as described in Patent Document 1 is covered with a fluororesin tube, the porous elastic body is integrated with the fluororesin tube. In this case, it was found that the fluororesin tube was damaged along with the porous elastic body at the center in the shaft direction during the secondary heating.
JP 2005-62534 A JP 2005-171229 A

  Accordingly, the present invention provides a fixing roller having an elastic layer made of a non-foamed, closed-cell silicone elastomer porous body that can be manufactured while suppressing damage during secondary heating of a silicone elastomer covered with a fluororesin tube. And it aims at providing the manufacturing method.

According to the first aspect of the present invention, a liquid silicone rubber in which a fixing roller shaft is concentrically disposed in a fluororesin tube and is cured between the fluororesin tube and the shaft to produce a silicone elastomer. Introducing a water-in-oil emulsion composition containing a material, an emulsifier and water, and primary curing this by primary heating, thereby forming an elastic layer precursor whose outside is covered with the fluororesin tube, The elastic layer precursor is provided with at least one hole that opens in at least one of the first end surface and the second end surface and extends into the elastic layer precursor, and the elastic layer precursor is subjected to secondary heating. And at least a part of the water is removed from the pores to form an elastic layer made of a closed-cell porous elastic body. Method for manufacturing a fixing roller, wherein Mukoto is provided.

  According to the present invention, a fixing roller having an elastic layer made of a silicone elastomer porous body that is covered with a fluororesin tube and has uniform fine cells (bubbles) without foaming phenomenon is subjected to secondary heating. It is possible to manufacture while suppressing breakage.

  Hereinafter, the present invention will be described in various aspects.

  The fixing roller according to the present invention includes a (cylindrical or columnar) shaft, an elastic layer provided on the outer peripheral surface of the shaft, and having a first end surface and a second end surface that respectively intersect the axial direction of the shaft; A fluororesin tube provided outside the elastic layer is provided. The elastic layer is made of a closed-cell silicone elastomer porous body that is non-foamed (does not utilize the foaming phenomenon for the formation of pores (cells)). The elastic layer is provided with at least one hole that opens into at least one of the first end surface and the second end surface and extends into the elastic layer.

  The elastic layer in the fixing roller of the present invention is composed of a closed-cell type silicone elastomer porous body, and this porous body is of a non-foaming type. That is, a foaming agent (blowing agent or foaming agent) is not used for forming the porous body.

  The elastic layer comprising the non-foamed closed-cell silicone elastomer porous body can be formed from a water-in-oil emulsion composition containing a liquid silicone rubber material that is cured to produce a silicone elastomer, an emulsifier, and water. preferable.

  The liquid silicone rubber material in the emulsion composition is not particularly limited as long as it can be cured by heating to produce a silicone elastomer, but it is preferable to use a so-called addition reaction curable liquid silicone rubber. The addition reaction curable liquid silicone rubber contains a polysiloxane having an unsaturated aliphatic group as a main agent and an active hydrogen-containing polysiloxane as a crosslinking agent. In the polysiloxane having an unsaturated aliphatic group, the unsaturated aliphatic group is introduced at both ends and can also be introduced as a side chain. Such polysiloxane having an unsaturated aliphatic group can be represented by, for example, the following formula (1).

In Formula (1), R ¹ represents an unsaturated aliphatic group, and each R ² represents a C ₁ -C ₄ lower alkyl group, a fluorine-substituted C ₁ -C ₄ lower alkyl group, or a phenyl group. a + b is usually 50 to 2000. The unsaturated aliphatic group represented by R ¹ is usually a vinyl group. Each R ² is usually a methyl group.

  The active hydrogen-containing polysiloxane (hydrogen polysiloxane) acts as a crosslinking agent for the polysiloxane having an unsaturated aliphatic group, and has hydrogen atoms (active hydrogen) bonded to silicon atoms in the main chain. It is preferable that 3 or more hydrogen atoms exist per molecule of active hydrogen-containing polysiloxane. Such an active hydrogen-containing polysiloxane can be represented, for example, by the following formula (2).

In the formula (2), R ³ represents hydrogen or a C _{1 to} C ₄ lower alkyl group, and R ⁴ represents a C _{1 to} C ₄ lower alkyl group. c + d is usually 8 to 100. The lower alkyl group represented by R ³ and R ⁴ is usually a methyl group.

  These liquid silicone rubber materials are commercially available. In addition, in the commercial product, the polysiloxane having an unsaturated aliphatic group constituting the addition reaction curable liquid silicone rubber and the active hydrogen-containing polysiloxane are provided in separate packages, and are necessary for curing both described in detail below. The curing catalyst is added to the active hydrogen-containing polysiloxane.

  The emulsifier in the emulsion composition acts as a dispersion stabilizer for stably dispersing water in the emulsion. That is, the emulsifier has an affinity for water and also an affinity for the liquid silicone rubber material. Emulsifiers include anionic, cationic, zwitterionic and nonionic surfactants. Examples of anionic surfactants include higher fatty acid salts, higher alcohol sulfates, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and polyethylene glycol sulfates. Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyalkylene fatty acid esters, polyoxyethylene polyoxypropylenes, and fatty acid monoglycerides. Can be mentioned. Examples of the cationic surfactant include aliphatic amine salts, quaternary ammonium salts, and alkylpyridinium salts. Examples of zwitterionic surfactants include carboxybetaine type and glycine type. The emulsifier preferably has a hydrophilic group such as an ether group. Further, the emulsifier usually has an HLB value of 3 to 13, preferably 4 to 11. More preferably, two types of ether-modified silicone oils having HLB values different by 3 or more are used in combination as emulsifiers. In that case, more preferably, a first ether-modified silicone oil having an HLB value of 7 to 11 and a second ether-modified silicone oil having an HLB value of 4 to 7 are used in combination. Any ether-modified silicone oil can be obtained by introducing a polyether group into the side chain of polysiloxane, and can be represented by, for example, the following formula (3).

In the formula (3), R ⁵ represents a C _{1 to} C ₄ lower alkyl group, and R ⁶ represents a polyether group. e + f is usually 8 to 100. The lower alkyl group represented by R ⁵ is usually a methyl group. The polyether group represented by R ⁶ is usually a (C ₂ H ₄ O) _x group, a (C ₃ H ₆ O) _y group, or a (C ₂ H ₄ O) _x (C ₃ H ₆ O). ) _{Contains y} group. The HLB value is determined mainly by the number of x and y. These silicone oil materials having a surface active action are commercially available.

  Needless to say, water is present as a discontinuous phase in the form of particles (water droplets) in the water-in-oil emulsion composition. As will be described in detail later, the particle diameter of the water particles substantially determines the diameter of the cells (pores) of the porous cell body of the present invention. Water may be present in the form of particles having an average particle size of 1-80 μm. The size of the water particles in the emulsion can be measured by microscopic observation.

  The water-in-oil emulsion composition can contain a curing catalyst in order to cure the liquid silicone rubber material. As the curing catalyst, a platinum catalyst can be used as known per se. The amount of the platinum catalyst is about 1 to 100 ppm by weight as platinum atoms. The curing catalyst may be added to the water-in-oil emulsion when producing the silicone elastomer porous body, but can also be blended when producing the emulsion.

  In the water-in-oil emulsion composition, the emulsifier is used in a proportion of 0.2 to 5.5 parts by weight and the water is used in a proportion of 10 to 250 parts by weight with respect to 100 parts by weight of the liquid silicone rubber material. It is preferable for obtaining an emulsion particularly excellent in water dispersion stability. When the emulsifier is a combination of the first ether-modified silicone oil and the second ether-modified silicone oil, 0.15 to 3 of the first ether-modified silicone oil is added to 100 parts by weight of the liquid silicone rubber material. It is preferable to use the second ether-modified silicone oil in an amount of 0.05 to 2 parts by weight (total 0.2 to 5.5 parts by weight) in an amount of 0.5 parts by weight. Moreover, when a liquid silicone rubber material consists of a combination of polysiloxane having an unsaturated aliphatic group and active hydrogen-containing polysiloxane, the weight ratio of the former to the latter is preferably 6: 4 to 4: 6.

  The water-in-oil emulsion composition can contain various additives. Examples of such additives include colorants (pigments, dyes), conductivity-imparting materials (carbon black, metal powder, etc.), and reinforcing fillers (silica, etc.). Further, the water-in-oil emulsion may contain a non-reactive silicone oil having a low molecular weight in order to adjust the viscosity of the emulsion for the purpose of facilitating defoaming, for example. When the water-in-oil emulsion has a viscosity of 1 cSt to 200,000 cSt, defoaming can be easily performed and it is convenient for handling.

  The water-in-oil emulsion composition can be produced by various methods. Generally, it is produced by mixing a liquid silicone rubber material, an emulsifier, and water together with further additives as necessary, and stirring thoroughly. When the liquid silicone rubber material is provided by a combination of a polysiloxane having an unsaturated aliphatic group and an active hydrogen-containing polysiloxane, a silicone oil material having a surface active activity with a polysiloxane having an unsaturated aliphatic group A part of the mixture can be mixed and stirred to obtain a first mixture, while the active hydrogen-containing polysiloxane and the remainder of the emulsifier can be mixed and stirred to obtain a second mixture. Next, while mixing and stirring the first mixture and the second mixture, water is gradually added and stirred to obtain a desired emulsion. Needless to say, the method for producing the water-in-oil emulsion is not limited thereto. The order of addition of the liquid silicone rubber material, the emulsifier, and water, and the additive added as necessary may be any. Stirring for forming the emulsion can be performed, for example, at a stirrer rotation speed of 300 rpm to 1000 rpm. After the emulsion is formed, the air present in the emulsion can be removed by subjecting it to a defoaming treatment without heating, for example, using a vacuum decompressor.

  As described in detail later, the elastic layer in the fixing roller of the present invention undergoes primary curing (formation of an elastic layer precursor) by primary heating of the water-in-oil emulsion and dehydration by secondary heating to obtain a fluororesin layer and It can be formed integrally. The elastic layer has both end faces (a first end face and a second end face) that intersect (usually perpendicular to) the axial direction of the shaft. The elastic layer is provided with at least one hole that opens to at least one end face of the both end faces and extends into the elastic layer. Since the elastic layer exhibits elasticity, the presence of holes provided in the elastic layer does not substantially adversely affect the performance of the elastic layer in the fixing roller. That is, in the fixing roller of the present invention, it has been confirmed that the elastic layer having holes exhibits the same performance as the corresponding elastic layer having no such holes.

  From the viewpoint of moisture removal efficiency, the total length of the holes provided in the elastic layer is preferably 50% or more of the length of the elastic layer in the shaft direction. The total length of the hole means the length of the hole when there is one hole, and means the total length of each hole when there are a plurality of holes. The thickness of the elastic layer is usually 3 to 15 mm.

  Furthermore, since the shaft has a large heat capacity and large heat conduction, excessive heat is supplied to the vicinity of the shaft, and vapor pressure is likely to increase. Since it cannot be said that there is no possibility of influencing, it is necessary to provide all the holes so as to exist in the inner region of the elastic layer from the center in the thickness direction of the elastic layer to the shaft. preferable.

  In addition, from the viewpoint of ease of moisture removal and formation, the hole is preferably a through hole that opens at both end faces of the elastic layer, rather than a non-through hole that opens only at one end face of the elastic layer. The hole preferably extends substantially parallel to the axial direction of the shaft. And preferably a plurality of holes are provided, more preferably three or more.

There is no particular limitation on the cross-sectional shape of the hole, and a hole such as a circle, a polygon such as a square or a triangle, or a star shape can be provided, and a star shape is preferable from the viewpoint of moisture discharge, but the deformation of the elastic layer Considering the influence, a circular hole is desirable. From the viewpoint of the efficiency of water discharge, the opening area of one hole is preferably 0.008 mm ² or more. The larger the opening area of the hole, the better the water discharging efficiency. However, in order to suppress the influence on the performance of the elastic layer as much as possible, it is preferably 3 mm ² or less.

  Further, in order to uniformly discharge moisture in the elastic layer, when there are a plurality of holes, it is preferable that the holes are arranged on the circumference at equal angular intervals with respect to the central axis of the shaft.

  The fluororesin tube is provided so as to cover the peripheral surface of the elastic layer for the purpose of improving transferability of toner, preventing adhesion of paper powder, preventing offset with respect to toner, and the like. The fluororesin tube may be heat-shrinkable or non-heat-shrinkable. Such a fluororesin tube is formed of a fluororesin such as polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), or the like. can do. The thickness of the fluororesin tube is usually 0.02 mm to 0.15 mm. In order to improve the adhesion between the fluororesin tube and the elastic layer, the inner surface of the fluororesin tube is treated in advance with a solution of liquid ammonia and metallic sodium, a solution of naphthalene, tetrahydrofuran and metallic sodium, or excimer laser irradiation. It is possible to adopt a general method such as doing.

  In the fixing roller of the present invention, the fluororesin tube constitutes the outermost layer of the fixing roller (that is, the outer surface of the fluororesin tube is exposed).

  Several aspects of the invention will now be described with reference to the drawings. In all the drawings, similar elements are denoted by the same reference numerals.

  FIG. 1 is a partially broken longitudinal sectional view of a fixing roller 10 according to one aspect of the present invention. FIG. 2 is an enlarged view showing a sectional view taken along line II-II in FIG.

  The fixing roller 10 has a columnar or cylindrical shaft 12 made of metal or the like. The shaft 12 includes a shaft main body 121 on which an elastic layer is formed, and journal portions 122 a and 122 b formed integrally with the shaft main body on both sides of the shaft main body 121. An elastic layer 14 made of a non-foamed closed-cell silicone elastomer porous body is provided so as to cover the entire outer periphery of the shaft body 121. A fluororesin tube 18 is provided to cover the outer periphery of the elastic layer 14.

  The elastic layer 14 has a first end surface 14 a and a second end surface 14 b that respectively intersect the axial direction of the shaft 12. In FIG. 1, the first end surface 14 a and the second end surface 14 b are orthogonal to the axial direction of the shaft 12 and constitute the same plane as both end surfaces of the shaft main body 121. And the 2nd end surface 14b does not necessarily need to comprise the same plane as the both end surfaces of the shaft main body 121. FIG.

  The elastic layer 14 includes at least one (preferably, for example, a plurality of, for example, three or four) opening in at least one of the first end surface 14a and the second end surface 14b of the elastic layer 14 and extending into the elastic layer 14. Holes). In FIG. 1, two through holes 16 a and 16 b that open at both the first end surface 14 a and the second end surface 14 b of the elastic layer 14 and extend in the elastic layer 14 parallel to the axial direction of the shaft 12 are seen. Can do.

  Referring to FIG. 2, there are four holes (holes 16a to 16d; holes 16c and 16d have the same structure as holes 16a and 16b and are through holes). Each of the holes 16a to 16d is entirely located from a position that is half the radial thickness of the elastic layer 14 (a line (center line) CL connecting the radial center of the elastic layer 14) to the outer surface 14c of the elastic layer 14. 2 (outer region) 142, but as shown in FIG. 2, it is present in the region (inner region) 141 from the center line CL of the elastic layer 14 to the shaft body 121. Preferred for reasons.

  The holes 16a to 16d shown in FIG. 2 are arranged on the circumference at equal angular intervals with respect to the central axis CA of the shaft (shaft body 121) (the distance from the central axis CA is equal).

  FIG. 3 shows a cross section of the fixing roller 20 having the same structure as the fixing roller 10 shown in FIGS. 1 and 2 except that the number of holes is three. In the fixing roller 20, the three holes 22a, 22b and 22c similar to the holes 16a to 16d in the fixing roller 10 shown in FIGS. 1 to 2 are entirely present in the inner region 141 of the elastic layer. The holes 22a to 22c are arranged on the circumference at equal angular intervals with respect to the central axis CA of the shaft (shaft body 121) (the distance from the central axis CA is equal).

  The fixing roller according to the present invention has a fixing roller shaft concentrically disposed in a fluororesin tube, and a raw material composition of a non-foamed closed cell silicone elastomer porous body between the fluororesin tube and the shaft. (For example, the water-in-oil emulsion composition described above) is introduced, and this is subjected to primary heating and primary curing, thereby forming an elastic layer precursor whose outside is covered with a fluororesin tube, and an elastic layer precursor. In addition, at least one hole is formed in at least one end face of the both end faces and extends into the elastic layer precursor, and the elastic layer precursor is secondarily cured by secondary heating, and at least a part of water is It can manufacture by removing from a hole and forming the elastic layer which consists of a non-foaming type closed-cell type porous elastic body. In that case, the fluororesin tube is disposed in contact with the inner wall of a cylindrical mold having at least one hole forming means, the shaft is disposed concentrically with the fluororesin tube, and the water-in-oil emulsion composition Is formed between the fluororesin tube and the shaft, the water-in-oil emulsion composition is primarily cured by primary heating, and then the mold is removed to form the holes in the elastic layer precursor. Can do. The hole forming means can be constituted by a linear body such as a pin, a wire, a thread, and a string. Thereafter, the obtained integrated structure (an integrated structure comprising the shaft, the elastic layer precursor formed around the shaft and the hole, and the fluororesin tube formed on the outer periphery of the elastic layer) is secondarily heated. Then, it can be secondarily cured to obtain a fixing roller.

  For example, a mold 30 as shown in FIG. 4 can be used. The molding die 30 includes a cylindrical body 32 made of metal or the like having a diameter larger than that of the main body of the shaft 12 for the fixing roller and having a long axial length. Both open ends of the cylindrical body 32 are closed by fitting plugs 34 and 36 having heads 341 and 361, respectively. The plugs 34 and 36 have recesses 342 and 362 for receiving the journal portions 122a and 122b of the shaft 12, respectively. The distal end surfaces of the plug bodies 34 and 36 are in contact with the end surface of the shaft body. One plug body 34 has one or more linear bodies forming holes for discharging moisture, such as the holes 16a to 16d and 22a to 22d shown in FIGS. 1 to 3, such as rigid pins 38a and 38b. Is separated from the outer peripheral surface of the shaft main body 122, and one end is fixed to the plug body 34 by screwing or the like. The other ends of the pins 38a and 38b are in contact with the distal end surface of the other plug body 36, respectively. In addition, one or more injection ports 343 and 344 for injecting the water-in-oil emulsion composition pass through the plug body 34.

  In operation, the fluororesin tube 18 is disposed in contact with the inner wall of the cylindrical body 32, the shaft 12 is accommodated in the cylindrical body 32, and both ends of the cylindrical body are closed with plugs 34 and 36. Thereafter, the water-in-oil emulsion composition is injected into the cylindrical body 32 from the injection ports 343 and 344, and then the injection ports 343 and 344 are closed. Next, the emulsion composition is primarily cured by primary heating to form an elastic layer precursor having holes corresponding to the pins 38a and 38b between the resin tube 18 and the shaft. After that, the shaft 12 having the elastic layer precursor whose outer periphery is covered with the fluorine tube 18 is removed from the molding die, subjected to secondary heating, and dehydrated from the holes. Thus, since the hole provided in the elastic layer (precursor) according to the present invention fulfills the function of discharging water, it can be referred to as a water discharge hole.

  The moisture discharge hole can also be formed by forming an elastic layer precursor whose outer periphery is covered with a fluororesin tube, and then piercing the elastic layer precursor with a relatively rigid linear body. For example, the fluororesin tube is disposed in contact with the inner wall of the cylindrical mold, the shaft is disposed concentrically, the water-in-oil emulsion composition is introduced between the fluororesin tube and the shaft, The water-in-oil emulsion composition is primarily cured by primary heating and then demolded to obtain a shaft having an elastic layer precursor whose outer periphery is covered with a fluororesin tube. Thereafter, holes can be formed in the elastic layer precursor whose outer periphery is covered with a fluororesin tube.

  In the primary heating, it is preferable to use a heating temperature of 150 ° C. or lower in order to heat and cure the liquid silicone rubber material without volatilizing water in the water-in-oil emulsion composition. The heating temperature at the time of primary heating is usually 80 ° C. or higher, and the heating time is usually about 5 minutes to 150 minutes. By this primary heating, the liquid silicone rubber is cured, and the water particles in the emulsion are confined in the state of the emulsion. This primary cured silicone rubber is cured to such an extent that it can withstand the expansion force upon evaporation of water by secondary heating described below.

  The secondary heating for removing moisture from the primary cured silicone rubber (elastic layer precursor) containing water particles through the moisture discharge hole is preferably performed at a temperature of 70 ° C to 300 ° C. If the secondary heating temperature is less than 70 ° C., it takes a long time to remove water, and if the heating temperature exceeds 300 ° C., the cured silicone rubber may be deteriorated. In heating at 70 ° C. to 300 ° C., moisture is volatilized and removed in 1 hour to 24 hours. Secondary heating volatilizes and removes water as water vapor, and the silicone rubber material is finally cured. The water that has been volatilized and removed leaves cells with a pore size approximately equal to the particle size of the water particles in the cured silicone rubber material (silicone elastomer). The outer surface of the elastic layer precursor is covered with a fluororesin tube, but since the moisture discharge hole is formed in the elastic layer precursor, the elastic layer is prevented from being damaged during the secondary heating. The

  Thus, the water-in-oil emulsion composition can produce a silicone elastomer without causing a foaming phenomenon. The water particles in the water-in-oil emulsion composition are trapped in the silicone rubber cured by the primary heating, and only volatilize during the secondary heating. In this way, an elastic layer made of a non-foamed, substantially closed-cell silicone elastomer porous body is obtained. This porous body has fine cells (pores), a narrow cell size distribution, and high uniformity. In addition, during the secondary heating, moisture is efficiently removed through the moisture holes, and the elastic layer is prevented from tearing and breaking. The closed-cell silicone elastomer porous body may have a single bubble ratio of 80% or more as defined in JP-A-2005-206884. Further, since the closed-cell type silicone elastomer porous body is non-foaming type, the sphericity of the cells (pores) is significantly higher than that of the porous body made of foam. The non-foaming type means that cells (pores) satisfying the relationship between the major axis and the minor axis represented by the formula (A) shown in JP-A-2005-206884 occupy 50% or more of the total number of cells (pores). Furthermore, it can be said that the cells (pores) that also satisfy the condition given by the formula (B) shown in JP-A-2005-206884 occupy 80% or more of the total number of cells (pores). .

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples.

Examples 1-9
In Examples 1 to 5, liquid silicone rubber (trade name DY35-7002) obtained from Toray Dow Corning was used as the liquid silicone rubber material. In this liquid silicone rubber, active hydrogen-containing polysiloxane and vinyl group-containing polysiloxane are provided as separate packages, and a catalytic amount of a platinum catalyst is added to the vinyl group-containing polysiloxane. Hereinafter, the former is indicated as silicone rubber A agent, and the latter is indicated as silicone rubber B agent. The active hydrogen-containing polysiloxane has a structure of the above formula (2) in which each R ⁴ is a methyl group, while the vinyl group-containing silicone oil has each R ¹ is a vinyl group and each R ² is a methyl group. It has a certain structure of the above formula (1).

Also, as an emulsifier, a mixture of two polyether-modified silicone oils (KF-618 (HLB value: 11) manufactured by Shin-Etsu Chemical Co., Ltd.) and KF-6015 (HLB value: 4) manufactured by the same company at a weight ratio of 1: 1. According to the product catalog, each of these polyether-modified silicone oils has a structure of the above formula (3) in which each R ⁵ is a methyl group, and R ⁶ represents (C ₂ H ₄ O) _x (C ₃ H ₆ O) _y group.

  Furthermore, the silica particle normally used as a reinforcing filler was also used.

  Liquid silicone rubber agent (weight ratio of silicone rubber A and B is 1: 1), water, silica particles and emulsifier are blended at a weight ratio of 100: 100: 3.75: 3.75 and stirred. A water-in-oil emulsion composition was prepared.

  A PFA tube having a diameter of 23.5 mm and a thickness of 50 μm is fixed to the inner wall of the cylindrical body (inner diameter: 24.5 mm) 32 of the molding die 30 shown in FIG. 4, and an iron shaft (outer diameter of the shaft body: 10 mm; shaft body) (Length of elastic layer forming portion): 200 mm), one end of the cylindrical body 32 is sealed with a plug body 34 having a linear pin body (outer diameter: 0.6 mm) having a circular cross section. The other end was sealed with a plug 36. The water-in-oil emulsion composition was injected from the inlets 342 and 343 provided in the stopper 34. Thereafter, the mold was primarily heated at 150 ° C. for 35 minutes and then demolded. The obtained fixing roller having the elastic layer covered with the PFA tube after heating the shaft having the elastic layer precursor whose outer surface is covered with the PFA tube to 240 ° C. and then secondary heating at the same temperature for 12 hours (Two fixing rollers were produced for each example). At this time, the damage in the elastic layer of the fixing roller was visually observed, and the ratio (breakage rate) of the number of fixing rollers in which the elastic layer was damaged to the total number of fixing rollers prepared in each example was calculated. The spacing of the pin body from the shaft is as shown in Table 1, and is the distance from the point on the pin body circumference closest to the shaft in the radial direction of the pin body to the point on the shaft circumference in the radial direction. is there.

  The number of pin bodies is 0 (example 1 (comparative example), 1 (examples 2 to 3), 2 (example 4; the two pin bodies are symmetrical on the shaft and arranged on the same circumference), 3 (example 5) : The pin bodies are arranged on the same circumference at equal angular intervals with respect to the central axis of the shaft. 4 (Examples 6 to 9; The average pore size of the obtained elastic layer was 50 μm and was uniform, and the results are shown in Table 1.

From the results shown in Table 1, it can be seen that the opening area of the moisture discharge hole is preferably 0.008 mm ² or more.

1 is a schematic cross-sectional view showing a fixing roller according to one aspect of the present invention. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 5 is a schematic sectional view showing a fixing roller according to another aspect of the present invention. Sectional drawing for demonstrating a shaping | molding die.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20 ... Fixing roller 12 ... Shaft 121 ... Shaft body 122a, 122b ... Journal part of shaft 14 ... Elastic layer 14a, 14b ... End surface of elastic layer 14c ... Outer surface of elastic layer 18 ... Fluoropolymer tube 141 ... Elastic layer Inner area 142 ... Outer area of elastic layer 16a to 16d, 22a to 22c ... Hole 30 ... Mold 32 ... Cylindrical body 34, 36 ... Plug body 343, 344 ... Emulsion injection port 38a, 38b ... Pin body CA ... Center of shaft Axis CL ... center line of elastic layer

Claims (4)

  A water-in-oil solution containing a liquid silicone rubber material, an emulsifier and water, which concentrically arranges a fixing roller shaft in a fluororesin tube and cures to form a silicone elastomer between the fluororesin tube and the shaft. The mold emulsion composition is introduced, and this is subjected to primary heating and primary curing, thereby forming an elastic layer precursor whose outside is covered with the fluororesin tube, and the elastic layer precursor includes the first layer An opening is formed in at least one of the end surface and the second end surface, and at least one hole extending into the elastic layer precursor is provided. The elastic layer precursor is secondarily heated to be secondarily cured, and the water A fixing layer comprising removing an at least part of the pores to form an elastic layer made of a closed-cell porous elastic body. The method of production. The fluororesin tube is disposed in contact with an inner wall of a cylindrical mold having at least one hole forming means, the shaft is disposed concentrically, and the water-in-oil emulsion composition is disposed on the fluororesin tube. The pores are formed in the elastic layer precursor by being introduced between the shaft and first cured by primary heating of the water-in-oil emulsion composition and then demolding. The method of manufacturing a fixing roller according to claim 1 . The fluororesin tube is disposed in contact with the inner wall of the cylindrical mold, the shaft is disposed concentrically, the water-in-oil emulsion composition is introduced between the fluororesin tube and the shaft, 2. The fixing roller according to claim 1 , wherein the water-in-oil emulsion composition is primarily cured by primary heating and then demolded, and then the holes are formed in the elastic layer precursor. Manufacturing method. The method for manufacturing a fixing roller according to claim 1 , wherein the hole forming means is constituted by a linear body.

Images