JP2006018152A - Heat fixing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat fixing member having excellent heat conductivity, heat resistance, low compression permanent set and high durability. <P>SOLUTION: An elastic layer of the fixing member is formed by heating and curing an addition type silicone rubber composition containing (a) an organic polysiloxane containing alkenyl group, (b) an organo hydrogen polysiloxane and (c) 30-60 vol.% nitride powder surface treated with a silane compound containing an unsaturated group reactive with the organo hydrogen polysiloxane. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat fixing member such as a fixing roller, a belt, or a film used as a heat fixing device of a toner image forming apparatus such as a copying machine, a printer, or a facsimile machine.

  In general, a pair of heated rollers and rollers, a film and rollers, a belt and rollers, and a belt and belt are pressed against each other in the heat fixing apparatus, and a transfer paper having an unfixed toner image is transferred to the heat fixing device. It is sandwiched and conveyed between rotating bodies (nip part). In this process, the unfixed toner image is heated and softened in the nip portion and is pressed against the recording paper by the applied pressure. Thereafter, after cooling and solidification, a permanent toner image is formed on the recording paper.

In general, the member in contact with the unfixed toner is called a fixing roller, a fixing belt, a fixing film, or the like depending on the form.
In recent years, color development of toner image forming apparatuses such as copying machines, printers, facsimiles and the like has progressed, and the fixing members mounted on these are heat resistant materials such as metal, heat-resistant resin roller base materials, belt base materials, and film base materials. In many cases, the elastic body is formed by laminating a single layer or multiple layers. It is known that the elastic layer has an effect of preventing color image scattering and gloss unevenness, is required to be at least 100 μm, and the effect is recognized as the thickness increases.

  However, the use of the elastic layer greatly impairs the thermal conductivity of the fixing member. Therefore, technical development for improving the thermal conductivity of the elastic layer has been actively conducted. Patent Document 1 discloses a technique in which a silicone rubber elastic layer is blended with a metal oxide such as aluminum oxide, titanium oxide or iron oxide, or a thermally conductive inorganic filler such as quartz.

  Patent Document 2 discloses a fixing belt having an elastic layer having a thickness of 20 to 200 μm made of an addition type silicone rubber having a thermal conductivity of 0.42 to 2.1 W / (m · K) on a belt base material. ing. Examples of the filler for adjusting the thermal conductivity of the silicone rubber to a predetermined value include metal oxides such as crystalline silica, alumina, magnesium oxide, and beryllium oxide; nitrides such as boron nitride and aluminum nitride A thermal conductivity imparting material represented by a metal carbide such as silicon carbide.

Patent Document 3 discloses a technology in which a filler having a thermal conductivity of 16.7 W / (m · K) or more is contained in an elastic layer and heat is efficiently transferred to a heated object with a small amount of filler. . Here, specific examples of silicon filler (SiC) / silicon nitride (Si) are used as a filler of 16.7 W / (m · K) or more in fluororubber in which fluororesin particles such as PFA, PTFE, and FEP are dispersed. ₃ N ₄ ), boron nitride (BN), aluminum nitride (AlN), alumina (Al 2 O 3), Ni, Fe, Al, etc., with an average particle size of 0.1 to 20 μm or less and a content of 5 to 50 wt% Distributed.
Japanese Patent Laid-Open No. 01-040868 JP 09-179421 A JP 2000-187407 A

In the fixing belt using the silicone rubber and the filler described in Patent Documents 1 and 2, the material composition that can be used is limited, and it may be difficult to achieve high thermal conductivity. Further, nitrides such as silicon nitride (Si ₃ N ₄ ), boron nitride (BN), and aluminum nitride (AlN), which are particles having high thermal conductivity, used in the heating member described in Patent Document 3, When blended with an addition-type silicone rubber, the heat resistance may decrease. In addition, in a fixing member composed of a base material, an elastic layer, and a release layer, if this is used for an elastic layer, there may be a problem in durability during use at a high temperature for a long time. That is, when this fixing member is used, the compression set characteristic of the elastic layer is deteriorated due to thermal deterioration, the deformation of the nip portion during rest is not recovered at startup, and gloss unevenness due to deformation unevenness occurs during solid image fixing. Image defects called “set marks” may occur, or the hardness of the elastic layer may change due to thermal deterioration, resulting in an imbalance in the conveyance of the recording paper, which may cause conveyance defects such as paper wrinkles and paper curl. It was.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a highly durable fixing member that is excellent in heat conduction and excellent in heat resistance and low compression set.

In order to achieve the above object, in a fixing member having at least a base material, an elastic layer provided on the base material, and a release layer provided on the elastic layer,
The elastic layer is composed of (a) an organopolysiloxane containing an alkenyl group, (b) an organohydrogenpolysiloxane, and (c) a silane compound containing an unsaturated group having reactivity with the organohydrogenpolysiloxane. The present invention relates to a fixing member obtained by heat-curing an addition-type silicone rubber composition containing a surface-treated nitride powder of 30 to 60 vol%.

  In the present invention, an addition type silicone rubber composition containing 30-60 vol% nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition type silicone (organohydrogenpolysiloxane). By using an elastic layer obtained by heat-curing an object, it is possible to provide a highly durable fixing member excellent in heat conduction and excellent in heat resistance and low compression set.

  In addition, when the fixing member of the present invention is used as a heat fixing member of an image forming apparatus, the deformation of the nip portion at rest is effectively recovered at the time of start-up, and the elastic layer is deformed due to an image defect called “set trace” or thermal deterioration. Hardness change does not occur. Further, there is no conveyance failure such as paper wrinkles and paper curls due to the imbalance in the conveyance of the recording paper.

(Fixing member)
Hereinafter, the present invention will be described in detail. As shown in FIG. 1, the fixing member of the present invention includes an elastic layer 2 on a substrate 1 and a release layer 3 via the elastic layer 2.

(Base material)
The base member 1 of the fixing member of the present invention is not particularly limited in its shape, structure, size and the like, and can be appropriately selected from those known per se according to the purpose. The material of these base materials is not particularly limited as long as the material is excellent in heat resistance, mechanical strength, and good thermal conductivity. For example, in the case of a roll, aluminum, SUS, iron, Examples thereof include metals such as copper and nickel, alloys, and ceramics. Examples of the base material suitable for the belt-shaped member include heat-resistant resin materials that can be used at 150 to 180 ° C., such as polyimide resin, fluorine resin, and polyester resin, in addition to the above materials. In particular, regarding these belt-like base materials, an endless belt is more preferable because if there is a seam, the pressure applied to the portion changes at the time of fixing and affects the image quality.

  The thickness of the roll-shaped substrate is preferably in the range of 0.1 to 10 mm, more preferably in the range of 0.1 to 5 mm, and still more preferably in the range of 0.1 to 2 mm. Even if the thickness of the substrate is too thin or too thick, the same problem as that of the belt-shaped substrate occurs.

  The belt-shaped substrate preferably has a thickness of 15 to 100 μm, more preferably 40 to 150 μm, and still more preferably 20 to 50 μm. When the thickness of the substrate is 15 μm or more, there is no problem of excellent dimensional stability during heating and cooling and insufficient strength. Further, when the thickness is 100 μm or less, the flexibility is not lowered and the belt can be suitably used as a fixing belt.

(Addition type silicone rubber composition)
As the elastic layer 2 of the fixing member of the present invention, a heat-cured addition type silicone rubber composition containing 30 to 60 vol% of nitride powder is used. The nitride powder is surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone (organohydrogenpolysiloxane).

  Addition-type silicone rubber compositions include organopolysiloxanes containing alkenyl groups in addition to nitride powders, organohydrogenpolysiloxanes containing two or more hydrogen atoms bonded to silicon atoms in the molecule, and hydrosilylation reactions Examples include a catalyst and a filler. The organopolysiloxane and the organohydrogenpolysiloxane can be used alone or in combination.

(Nitride powder)
Examples of the nitride powder as the high thermal conductive material contained in the addition-type silicone rubber composition include aluminum nitride, boron nitride, silicon nitride and the like surface-treated with a silane compound. In order to obtain a nitride powder surface-treated with the silane compound of the present invention, first, aluminum nitride, boron nitride, silicon nitride or the like is prepared. These materials may be commercial products. For example, as aluminum nitride, TOYALNITE-FLA (manufactured by Toyo Aluminum Co., Ltd.), aluminum nitride powder shaper (Tokuyama Co., Ltd.), etc., as dendritic boronite as boron nitride Silicon nitride powder SH, HM, UH (manufactured by Onoda Cement Co., Ltd.), silicon nitride powder HM-5 (manufactured by Yakushima Electric Works Co., Ltd.) silicon nitride powder, such as Ride (Electrochemical Industry Co., Ltd.) G. S. A (Nippon Steel Pipe Co., Ltd.) or the like or a classified product thereof is used.

  The shape of the nitride powder may be any of a spherical shape, a scale shape (flat plate shape), a fibrous shape, etc., and among these, the spherical particles can be kneaded into the addition reaction curable silicone rubber composition. Excellent and particularly preferred.

  Next, the nitride powder is surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone.

  Examples of silane compounds include vinyltriethoxysilane, dimethylvinylmethoxysilane, dimethylvinylethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, vinyltrichlorosilane, dimethylvinylchlorosilane, methylvinyldichlorosilane, γ-methacryloxypropyltri. Methoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and the like can be used. When the nitride powder is surface-treated, these silane compounds can be used alone or in combination.

  As a surface treatment method using a silane compound, a dry method, a slurry method, a spray method, an integral blend method, or the like can be used. As the integral blend method, a direct method, a master batch method, or the like can be used.

  Specifically, as the surface treatment method, for example, a method of mixing nitride powder into a solution or dispersion in which a silane compound is dissolved, heating and drying, spraying the nitride powder, and then drying the powder. It can also be mentioned.

  In the addition-type silicone rubber composition of the present invention, the bond between the unsaturated group on the surface of the nitride powder and the organohydrogenpolysiloxane in the addition-type silicone rubber composition occurs simultaneously with heat curing of the addition-type silicone rubber composition. The heat resistance is improved as compared with the case where no nitride powder is added.

  The content of the surface-treated nitride powder in the addition-type silicone rubber composition is 30 to 60 vol%, preferably 40 to 55 vol%, from the viewpoints of improving thermal conductivity and maintaining mechanical strength. If it is in this range, after ensuring the softness | flexibility as rubber | gum, it can be made more than thermal conductivity 1W / (m * K), and can improve thermal conductivity effectively. If the content is less than 30 vol%, a sufficient effect of improving thermal conductivity cannot be obtained, and if it exceeds 60 vol%, the flexibility and permanent compression distortion as rubber become insufficient, resulting in image defects such as “nip marks”. If it is used as a fixing belt, it may break or break. The vol% of the nitride powder in the addition-type silicone rubber composition is calculated based on the volume calculated from the nitride powder density and its blending weight. The nitride powder density is measured using a dry automatic densitometer Accupic MIC-1330-01 (manufactured by Shimadzu Corporation) at an equilibrium judgment rate of 0.005 psig / min (as filling gas). Helium gas is used). From the obtained powder density and blending weight, the volume of the nitride powder was calculated, and from this volume, the volume filling rate (vol%) in the addition-type silicone rubber composition was calculated. The thermal conductivity is preferably 0.8 W / (m · K) or more, and more preferably 1.2 W / (m · K) or more.

  The average particle size of the surface-treated nitride powder is usually 0.5 to 50 μm, preferably 10 to 30 μm, from the viewpoint of dispersibility and obtaining a smooth layer. Here, the average particle diameter refers to a median diameter (D50) measured by a laser diffraction particle size distribution analyzer (for example, SALD-7000, manufactured by Shimadzu Corporation). When the particle size is 0.5 μm or more, excellent kneadability and high filling are possible, and an improvement in desired thermal conductivity can be expected. Moreover, moderate hardness can be maintained and it can be used conveniently as an elastic layer of a fixing member. When the average particle size is 50 μm or less, sufficient mechanical strength necessary for the elastic layer can be obtained. Further, although depending on the thickness of the elastic layer, it is possible to reduce local variations in the surface hardness of the fixing member, and to prevent image defects such as uneven gloss when fixing a solid image.

(Elastic layer)
The thickness of the elastic layer 2 is appropriately set in consideration of the application, the structure of the machine device to be installed, the target elasticity, the hardness of the material to be used, etc., but is generally set in the range of 100 μm to 3 mm. There are many. In particular, when formed on a belt-like base material, the one formed in the range of 100 μm to 500 μm makes the function of the fixing belt appear best. Of course, it may be processed into a required film thickness by polishing or the like after being formed into a film thickness thicker than this.

  The elastic layer 2 can be formed by a known method. For example, the addition-type silicone rubber composition or a solution obtained by diluting the addition-type silicone rubber composition with an appropriate solvent such as toluene, xylene, heptane, etc. is applied to the belt substrate, and then heated and cured. A general coating method may be used as an application method to the belt substrate, and examples thereof include spray coating, dip coating, knife coating, and the like. The curing conditions may be about 50 to 200 ° C. and about 3 to 15 minutes. Alternatively, a base material is attached in advance to a pipe-shaped mold having a predetermined inner diameter, and the additive silicone rubber composition is filled between the base material / pipe mold and heated at about 50 to 200 ° C. for about 10 to 60 minutes. -The method of demolding after hardening may be used.

  The elastic layer 2 may be laminated on a metal core through a primer, and the core is roughened by blasting, electrochemical etching, chemical etching, or a combination thereof. Further, it may be laminated through a primer having a thickness of about 1 to 3 μm as necessary. It is preferable to make the primer as thin as possible within a range that does not impair the adhesion. The hardness of the elastic layer is preferably Asker C hardness of 5 to 60 degrees, and more preferably 10 to 40 degrees.

  The addition-type silicone rubber composition of the present invention includes various fillers and, if necessary, pigments, in order to adjust the fluidity and improve the mechanical strength of the cured product, as long as the object of the present invention is not impaired. A heat-resistant agent, a flame retardant, a plasticizer, an adhesion imparting agent, or the like may be blended.

(Release layer)
The release layer 3 of the fixing member of the present invention is formed using a fluororesin, silicone rubber, fluororubber or the like. From the viewpoint of durability, a fluororesin is more preferably used. Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), and ethylene / tetrafluoroethylene copolymer. (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene / chlorotrifluoroethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF) and the like can be selected and used as a mixture of two or more. Also good. These material forms may be any of dispersion, powder and the like, and may be formed into a tube shape or the like. From the viewpoint of heat resistance and releasability (non-contamination, non-adhesiveness), any one of PTFE, PFA, FEP, or a mixture of two or more thereof is more preferably used.

  When the fluororesin is a dispersion, powder or the like, a release layer is formed on the elastic layer 2 through a primer and a coating and drying, followed by a heating and baking process at about 320 to 350 ° C. for about 30 to 60 minutes. The When the fluororesin is in the form of a tube, a method in which the elastic layer is coated with a silicone-based adhesive or a tube whose base surface has been previously primed using a cylindrical mold and the substrate 1 are connected to the cylindrical mold. The mold release layer is formed by attaching to the mold and filling the above addition reaction curable silicone rubber composition between the base material / tube and heating, curing and bonding at about 50 to 200 ° C. for about 10 to 60 minutes. 3 is formed. It is preferable to make the thickness of the primer and the adhesive as thin as possible within a range that does not impair the adhesiveness. The primer is preferably finished with a thickness of about 1 to 3 μm and an adhesive thickness of about 5 to 15 μm.

  A fixing belt will be described as an example of the fixing member of the present invention.

Example 1
An aluminum nitride powder having an average particle size of 14.4 μm (TOYALNITE-FLA classified product manufactured by Toyo Aluminum Co., Ltd.) is immersed in an aqueous solution of 0.5 mass% vinyltriethoxysilane (GE Toshiba Silicone Co., Ltd. TSL8311), and then filtered. Water was removed and sufficiently dried at 120 ° C. to prepare a surface vinyl-treated aluminum nitride powder (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone). Subsequently, the surface vinyl-treated aluminum nitride powder was mixed with a liquid addition type silicone rubber composition DY35-561A / B (manufactured by Toray Dow Corning Silicone Co., Ltd.) using a universal mixing stirrer so as to be 45 vol%. A liquid addition type silicone rubber composition used for the elastic layer of the invention was obtained.

  A silicone primer (DY35-067: manufactured by Toray Dow Corning Silicone) is applied to the outer peripheral surface of a stainless steel endless metal belt having an outer diameter of 24 mm and a thickness of 25 μm by a known method, dried, and a primer having a thickness of about 1 μm. A layer was formed, and the liquid addition type silicone rubber composition was applied and heat-cured by a known method through this primer layer to form an elastic layer made of 300 μm addition type silicone rubber. A silicone adhesive (TSE3205: manufactured by GE Toshiba Silicones) serving as an adhesive layer was applied to the outer peripheral portion, and a PFA tube having a thickness of 25 μm was coated at the same time, and a release layer was formed by heat-bonding to prepare a fixing belt. .

(Example 2)
A fixing belt was produced in the same manner as in Example 1 except that the surface vinyl-treated aluminum nitride powder of Example 1 was 30 vol%.

Example 3
A fixing belt was produced in the same manner as in Example 1 except that the surface vinyl-treated aluminum nitride powder of Example 1 was 60 vol%.

Example 4
Boron nitride powder having an average particle size of 18.3 μm (Denkaboronite SGP manufactured by Denki Kagaku Kogyo Co., Ltd.) was immersed in an aqueous solution of 0.5% by mass vinyltriacetoxysilane (SZ6075 manufactured by Toray Dow Corning Silicone), followed by filtration. Then, water was removed, and it was sufficiently dried at 120 ° C. to prepare a surface vinyl-treated boron nitride powder (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone). . Subsequently, the surface vinyl-treated aluminum nitride powder was mixed with a liquid addition type silicone rubber composition DY35-561A / B (manufactured by Toray Dow Corning Silicone Co., Ltd.) using a universal mixing stirrer so as to be 45 vol%. A liquid addition type silicone rubber composition used for the elastic layer of the invention was obtained. Using this, a fixing belt was produced in the same manner as in Example 1.

(Example 5)
Silicon nitride powder having an average particle diameter of 16.7 μm (classified product of UH-44 manufactured by Onoda Cement Co., Ltd.) in an aqueous solution of 0.5 mass% γ-methacryloxypropyltrimethoxysilane (SZ6030 manufactured by Toray Dow Corning Silicone Co.). After soaking, filtering to remove water, sufficiently drying at 120 ° C., and surface-treated methacryl-treated silicon nitride powder (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone) ) Was prepared. Subsequently, the surface vinyl-treated aluminum nitride powder was mixed with a liquid addition type silicone rubber composition DY35-561A / B (manufactured by Toray Dow Corning Silicone Co., Ltd.) using a universal mixing stirrer so as to be 45 vol%. A liquid addition type silicone rubber composition used for the elastic layer of the invention was obtained. Using this, a fixing belt was produced in the same manner as in Example 1.

(Example 6)
Aluminum nitride powder having an average particle size of 3.1 μm (TOYALNITE-FLA classification product manufactured by Toyo Aluminum Co., Ltd.) (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone) A fixing belt was produced in the same manner as in Example 1 except that it was used.

(Example 7)
Aluminum nitride powder with an average particle size of 10.1 μm (TOYALNITE-FLA classification product manufactured by Toyo Aluminum Co., Ltd.) (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone) A fixing belt was produced in the same manner as in Example 1 except that it was used.

(Example 8)
Aluminum nitride powder having an average particle size of 23.5 μm (TOYALNITE-FLG classification product manufactured by Toyo Aluminum Co., Ltd.) (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition type silicone) A fixing belt was produced in the same manner as in Example 1 except that it was used.

Example 9
Aluminum nitride powder with an average particle size of 29.8 μm (TOYALNITE-FLG classification product manufactured by Toyo Aluminum Co., Ltd.) (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition type silicone) A fixing belt was produced in the same manner as in Example 1 except that it was used.

(Example 10)
Aluminum nitride powder having an average particle size of 41.6 μm (TOYALNITE-FLG classification product manufactured by Toyo Aluminum Co., Ltd.) (nitride powder surface-treated with a silane compound containing an unsaturated group having reactivity with addition-type silicone) A fixing belt was produced in the same manner as in Example 1 except that it was used.

(Comparative Example 1)
Liquid addition type silicone rubber composition DY35-561A / B (Toray Dow) without surface treatment of the aluminum nitride powder having an average particle size of 14.4 μm used in Example 1 (classified product of TOYALNITE-FLA manufactured by Toyo Aluminum Co., Ltd.) Corning Silicone Co., Ltd.) was mixed using a universal mixing stirrer so as to be 45 vol%, and a liquid addition type silicone rubber composition used for the elastic layer of the present invention was obtained. Using this, a fixing belt was produced in the same manner as in Example 1.

(Comparative Example 2)
The aluminum nitride powder having an average particle size of 14.4 μm (classified product of TOYALNITE-FLA manufactured by Toyo Aluminum Co., Ltd.) used in Example 1 was immersed in an aqueous solution of 0.5% by mass hexamethyldisilazane (TSL8802 manufactured by GE Toshiba Silicone). Then, it was filtered to remove water and sufficiently dried at 120 ° C. to prepare a surface vinyl-treated aluminum nitride powder. Subsequently, this surface methylated aluminum nitride powder was mixed with a liquid addition type silicone rubber composition DY35-561A / B (manufactured by Toray Dow Corning Silicone Co., Ltd.) using a universal mixing stirrer so as to be 45 vol%. A liquid addition type silicone rubber composition used for the elastic layer of the invention was obtained. Using this, a fixing belt was produced in the same manner as in Example 1.

(Comparative Example 3)
A fixing belt was produced in the same manner as in Example 1 except that the surface vinyl-treated aluminum nitride powder of Example 1 was 20 vol%.

(Comparative Example 4)
A fixing belt was produced in the same manner as in Example 1 except that the surface vinyl-treated aluminum nitride powder of Example 1 was 65 vol%.

(Comparative Example 5)
A surface treatment was performed on alumina powder having an average particle size of 18.2 μm (AS-30 classified product manufactured by Showa Denko KK) in the same manner as in (Comparative Example 2) to prepare a surface methylated alumina nitride powder. Subsequently, the surface methylated alumina nitride powder was mixed with the liquid addition type silicone rubber composition DY35-561A / B (manufactured by Toray Dow Corning Silicone Co., Ltd.) using a universal mixing stirrer so as to be 40 vol%. A liquid addition type silicone rubber composition used for the elastic layer of the invention was obtained. Using this, a fixing belt was produced in the same manner as in Example 1.

(Comparative Example 6)
Surface treatment was performed on silicon carbide powder having an average particle size of 14.1 μm (classified product of GC800S manufactured by Yakushima Electric Works) in the same manner as in (Comparative Example 2) to prepare a surface methylated silicon carbide powder. Subsequently, this surface methylated silicon carbide powder was mixed with a liquid addition type silicone rubber composition DY35-561A / B (manufactured by Toray Dow Corning Silicone Co., Ltd.) using an all-purpose mixing stirrer so that the volume was 40 vol%. A liquid addition type silicone rubber composition used for the elastic layer of the invention was obtained. Using this, a fixing belt was produced in the same manner as in Example 1.
The examples and comparative examples are summarized in Table 1 above.

  Next, performance evaluation of the fixing belts of the present example and the comparative example will be described.

≪Performance evaluation≫
First, the heat fixing device used for performance evaluation will be described.

<Heat fixing device>
FIG. 2 is a schematic cross-sectional view of the heat fixing device 200 used for performance evaluation. The heat fixing device 200 is a belt heating type device using a ceramic heater as a heating body, and the fixing belts of the above-described embodiments and comparative examples are mounted as the fixing belt 210.

  The belt guide 216c is a heat and heat insulating belt guide. The ceramic heater 212 as a heating body is fixedly supported by being fitted into a groove formed along the longitudinal direction of the guide at substantially the center of the lower surface of the belt guide 216c. The cylindrical or endless fixing belt 210 of the present invention is loosely fitted on the belt guide 216c. The pressurizing rigid stay 222 is inserted inside the belt guide 216c.

  The pressure member 230 is an elastic pressure roller in this example. The pressure member 230 is formed by providing an elastic layer 230b of silicone rubber on the core metal 230a to reduce the hardness. The both ends of the core metal 230a are placed between the front side (not shown) and the chassis side plate on the back side of the apparatus. The bearings are arranged so as to be freely rotatable. The elastic pressure roller is covered with a PFA (tetrafluoroethylene / perfluoroalkyl ether copolymer) tube in order to improve surface properties.

  By pressing the pressure springs (not shown) between the both ends of the pressure rigid stay 222 and the spring receiving member (not shown) on the apparatus chassis side, a pressing force is applied to the pressure component stay 222. ing. As a result, the lower surface of the sliding plate 240 disposed on the lower surface of the belt guide 216c and the upper surface of the pressure roller 230 are pressed against each other with the fixing belt 210 interposed therebetween to form a fixing nip portion N having a predetermined width.

  The pressure roller 230 has an outer diameter of 20 mm, and is driven to rotate counterclockwise by the driving means M as indicated by an arrow. A rotational force acts on the fixing belt 210 by a frictional force between the pressure roller 230 and the outer surface of the fixing belt 210 by the rotational driving of the pressure roller 230, and the inner surface of the fixing belt 210 is a ceramic heater in the fixing nip portion N. While rotating in close contact with the lower surface of 212, it rotates outwardly of the belt guide 216c in a clockwise direction as indicated by an arrow at a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 230 (pressure roller drive system). .

  Based on the print start signal, rotation of the pressure roller 230 is started, and heat-up of the ceramic heater 212 is started. When the rotation peripheral speed of the fixing belt 210 is stabilized by the rotation of the pressure roller 230 and the temperature of the ceramic heater 212 has risen to a predetermined temperature, there is a gap between the fixing belt 210 and the pressure roller 230 in the fixing nip N. A recording material P carrying a toner image t as a heating material is introduced with the toner image carrying surface side facing the fixing belt 210 side. The recording material P is in close contact with the lower surface of the ceramic heater 212 via the fixing belt 210 in the fixing nip portion N, and moves and passes through the fixing nip portion N together with the fixing belt 210. In the moving and passing process, the heat of the ceramic heater 212 is applied to the recording material P via the fixing belt 210, and the toner image t is heated and fixed on the surface of the recording material P. The recording material P that has passed through the fixing nip N is separated from the outer surface of the fixing belt 210 and conveyed.

  The ceramic heater 212 as a heating body is a horizontally long linear heating body having a low heat capacity and having a longitudinal direction in a direction orthogonal to the moving direction of the fixing belt 210 and the recording material P. A heater substrate 212a made of aluminum nitride or the like, and a heating layer 212b provided on the surface of the heater substrate 212a along the length thereof, for example, an electric resistance material such as Ag / Pd (silver / palladium) is about 10 μm, width 1 The heat generating layer 212b provided by coating by ~ 5 mm by screen printing or the like, and a protective layer 212c made of glass or fluororesin, etc. provided thereon are the basic components. The ceramic heater to be used is not limited to this.

  And by supplying with electricity between the both ends of the heat_generation | fever layer 212b of the ceramic heater 212, the heat_generation | fever layer 212b will generate | occur | produce heat and the heater 212 will heat up rapidly. The heater temperature is detected by a temperature sensor (not shown), and energization of the heat generating layer 212b is controlled by a control circuit (not shown) so that the heater temperature is maintained at a predetermined temperature, and the heater 212 is temperature-controlled. .

  The ceramic heater 212 is fixedly supported by fitting the protective layer 212c upward in a groove formed along the longitudinal direction of the guide at the substantially central portion of the lower surface of the belt guide 216c. The surface of the sliding member 240 of the ceramic heater 212 and the inner surface of the fixing belt 210 slide in contact with each other at the fixing nip portion N in contact with the fixing belt 210. The nip width is changed according to the process speed in order to secure the nip residence time of the recording paper.

<Nip mark evaluation method>
Attach the belt for evaluation to the heating fixing device 1 set at a fixing temperature of 200 ° C., rotate it idle for 10 minutes, warm the heating fixing device and fixing belt sufficiently, turn off the power, and pressurize for 20 hours. Then, the power was turned on again, and the cyan unfixed toner image was passed through and the nip mark of the fixed solid image was visually confirmed. The recording paper was evaluated with a standard thickness of 82 g / m ² paper. The nip width of the heat fixing device is set to 7.0 mm (pressure 20 kgf), and the process speed is set to 180 mm / sec.

<Heat resistance test>
The fixing belts of the present example and the comparative example were mounted on the heat fixing device 2 and subjected to idling at a fixing temperature of 220 ° C., taken out every 50 hours, and evaluated according to the nip mark evaluation method. The results are shown in Table 2. In other words, “after 50 hours” in Table 2 means that after performing idling processing at a fixing temperature of 220 ° C. for 50 hours, this belt is used as a nip mark evaluation method. After 10 minutes idling, warm the heat fixing device / fixing belt sufficiently, turn off the power and leave it under pressure for 20 hours, then turn on the power again and unfix cyan This is to visually confirm the nip mark of the toner image through the sheet and the fixed solid image. “After 100 hours” means that after that, the idling process is further performed at a fixing temperature of 220 ° C. for 50 hours, and the same nip mark evaluation is performed. Thereafter, such a process is repeated every 50 hours, and “after 150 hours” and “after 200 hours” are evaluated. The conditions during the idling process are set such that the nip width is 7.0 mm (pressure 20 kgf) and the process speed is 180 mm / sec.

OK: The nip trace cannot be visually confirmed, NG: The nip trace is visually confirmed. The belts of Examples 1 to 5 and Examples 7 to 9 are 200 hours, and no nip trace is recognized even in the evaluation of the nip trace after idling. Good heat resistance was confirmed. In the belts of Examples 6 and 10 as well, no nip mark was observed in the evaluation of the nip mark after the idling treatment for 150 hours, and good heat resistance was confirmed. However, the belt of Example 6 was confirmed to crack in the rubber layer at the end of idling treatment for 200 hours. This is presumably because the hardness was increased by the rubber highly filled with the heat conductive agent having a small particle diameter. Further, in the belt of Example 10, paper wrinkles that were attributed to softening of the rubber layer after idling occurred for 200 hours.

  The belt of Comparative Example 1 is not subjected to surface treatment on the thermal conductive agent (nitride powder), and the nip mark is confirmed in the nip mark evaluation after idling for 50 hours, and the heat resistance is the belt of the above example. It was inferior to.

  The nip mark was confirmed in the evaluation of the nip mark after the idling process of the belt of Comparative Example 2 for 50 hours. The heat conductive agent was surface-treated with hexamethylsilazane, and although the heat resistance was improved as compared with the belt of Comparative Example 1, it was inferior to the belt of the above Examples.

  The belt of Comparative Example 3 had a low blending amount of the thermal conductive agent, and sufficient thermal conductivity was not ensured. Therefore, the belt produced only a lower gloss than the belt of the Example, and was not at a level that could withstand practical use.

  Since the belt of Comparative Example 4 contained too much heat conductive agent, the elastic layer had insufficient permanent compression strain, and nip marks were recognized in the evaluation of nip marks in the initial state.

  A nip mark was confirmed in the evaluation of the nip mark after the idling of the belt of Comparative Example 5 for 150 hours. The heat conductive agent (alumina powder) was surface-treated with hexamethylsilazane, and although the heat resistance was improved as compared with the belt of Comparative Example 1, it was inferior to the belt of the above Examples.

  A nip mark was confirmed in the evaluation of the nip mark after the idling of the belt of Comparative Example 6 for 150 hours. The heat conductive agent (silicon carbide) was surface-treated with hexamethylsilazane, and although heat resistance was improved as compared with the belt of Comparative Example 1, it was inferior to the belt of the above Examples.

It is an example of the layer structure model figure of this invention fixing member. 1 is a schematic cross-sectional view of a heat fixing device used for performance evaluation of a fixing member of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Elastic layer 4 Release layer 200 Heat fixing apparatus 210 Fixing belt 212 Ceramic heater 216C Belt guide 222 Pressurizing rigid stay 230 Pressing member (pressing roller)
240 Sliding plate N Fixing nip portion t Toner image P Recording material

Claims (3)

In a fixing member having at least a base material, an elastic layer provided on the base material, and a release layer provided on the elastic layer,
The elastic layer is composed of (a) an organopolysiloxane containing an alkenyl group, (b) an organohydrogenpolysiloxane, and (c) a silane compound containing an unsaturated group having reactivity with the organohydrogenpolysiloxane. A fixing member obtained by heat-curing an addition-type silicone rubber composition containing a surface-treated nitride powder of 30 to 60 vol%.   The fixing member according to claim 1, wherein the nitride powder has an average particle size of 10 to 30 μm.   The fixing member according to claim 1, wherein the nitride powder is at least one powder selected from the group consisting of aluminum nitride powder, boron nitride powder, and silicon nitride powder.

Images