JP2014006305A - Planar heating element and image fixing device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a planar heating element having high adhesiveness between an electrode and a heating element although the planar heating element has a pair of metal electrodes.SOLUTION: The planar heating element includes: a planar molded article comprising a conductive resin composition containing a conductive substance and a resin; a pair of planar metal electrodes connected to the planar molded article; and a residue of a compound expressed by formula (1) or formula (2), which is present on an interface between the planar molded article and the planar metal electrodes. In formula (1), X represents a phenyl group or an amino group; and Y in formula (2) represents a methylamino group.

Description

  The present invention relates to a sheet heating element and an image fixing apparatus including the sheet heating element.

  An image fixing device is incorporated in an image forming apparatus such as a copying machine or a laser beam printer. The image fixing apparatus incorporates a heating element, and forms a fixed image by pressing the heating element against an unfixed image (see Patent Documents 1 to 3). The heating element is provided as a heating fixing belt as shown in FIG. 5, for example. The heat-generating fixing belt 10 in FIG. 5 is a pipe-shaped member, and includes a first insulating layer 1, a specific resistance heating element layer 2, a second insulating layer 3, a release layer 4, and an electrode layer 5. Have. 5A is a cross-sectional view taken along the axial direction of the pipe of the heat-generating fixing belt 10, and FIG. 5B is a cross-sectional view taken along the line II-II in FIG. 5A.

  The specific resistance heating element layer 2 of the heat fixing belt 10 includes a polyimide resin that is a matrix resin and a conductive substance such as metal fine particles or a carbon material. The electrode layer 5 is formed by applying a conductive paste or the like using a polyimide resin as a matrix to the specific resistance heating element layer 2.

JP 2006-294604 A JP 2009-92785 A JP 2009-109987 A

  As described above, it is known that the electrode layer in the heat-generating fixing belt is formed from a conductive paste. However, the electrode layer formed from the conductive paste may have a low mechanical strength, and cracks may occur during repeated use of the heat-generating fixing belt, or a defective hole may occur due to the generated spark. .

  Therefore, it is conceivable that the electrode layer in the heat fixing belt is a metal plate. However, the adhesive force between the electrode layer, which is a metal plate, and the specific resistance heating element layer may not be sufficient. Therefore, the present invention increases the bonding strength between a sheet-shaped molded article made of a conductive resin composition containing a conductive substance and a resin, and a pair of plate-shaped metal electrodes connected to the sheet-shaped molded article. An object of the present invention is to provide a planar heating element with little deterioration in performance even after repeated use.

That is, the first of the present invention relates to the planar heating element shown below.
[1] A planar molded product made of a conductive resin composition containing a conductive substance and a resin, a pair of plate metal electrodes connected to the planar molded product, the planar molded product, and the plate-shaped product A planar heating element having a residue of a compound represented by the following formula (1) or the following formula (2) at an interface with a metal electrode.

[2] The planar heating element according to [1], wherein the conductive substance is carbon material particles.
[3] The sheet heating element according to [1], wherein the resin is polyimide.
[4] The surface-shaped molded product is a pipe-shaped molded product, and the pair of plate-like metal electrodes are each in a ring shape, and are connected to both ends of the pipe-shaped molded product. Sheet heating element.
[5] The planar heating element according to [1], further including an elastic layer that covers an outer surface of the planar molded product.
[6] The planar heating element according to [1], further including a release layer that covers an outer surface of the planar molded product.

The second of the present invention relates to the following image fixing apparatus.
[7] An image fixing device including the planar heating element according to any one of [1] to [6].

  ADVANTAGE OF THE INVENTION According to this invention, although it is a planar heating element which has a pair of metal electrode and the heating element containing resin, the planar heating element with high adhesiveness of a metal electrode and a heating element is provided. The Therefore, a planar heating element is provided that does not easily deteriorate even when used repeatedly. The planar heating element of the present invention is preferably used as, for example, a fixing member of an image fixing device of an electrophotographic image forming apparatus.

It is a figure which shows an example of a structure of a planar heating element. It is a flowchart which shows an example of the manufacturing flow of a planar heating element. It is a figure which shows the structure of the coating device which apply | coats conductive resin dope. 1 is a diagram illustrating an example of a configuration of an image fixing device. It is a figure which shows the structure of the conventional heat fixing belt.

1. Planar heating element The planar heating element includes a planar molded product made of a conductive resin composition and a pair of plate-shaped metal electrodes connected to the planar molded product; and further, a reinforcement covering the planar molded product You may have a layer, an elastic body layer, and a mold release layer. An example of the configuration of the planar heating element is shown in FIGS. 1A is an external perspective view of the planar heating element 100, and FIG. 1B is a cross-sectional view of the planar heating element 100 in FIG. The sheet heating element 100 shown in FIGS. 1A and 1B has a pipe shape, and from the inner layer side, plate-like metal electrodes 110-1 and 110-2, a sheet molding 120, a reinforcing layer 130, an elastic body layer 140, The release layers 150 are stacked in this order.

  The inner diameter of the pipe-shaped planar heating element 100 as shown in FIG. 1 is appropriately set according to the application, but is 10 to 120 mm, for example, when used as a fixing member of a normal image fixing apparatus. is there.

  The pair of plate-like metal electrodes are preferably bonded to the end portions of the planar heating element. By providing a potential difference between the pair of plate-like metal electrodes, the planar heating element can generate heat. Examples of the material of the plate-like metal electrode include stainless steel (SUS), aluminum, copper, nickel and the like. The plate-like metal electrodes 110-1 and 110-2 in the pipe-shaped planar heating element 100 as shown in FIG. 1 are preferably ring-shaped. The thickness of the ring-shaped plate-like metal electrode is preferably thinner than the thickness of the planar molded product, and may be, for example, 40 to 100 μm.

  The planar molding is made of a conductive resin composition containing a conductive substance and a resin. The content of the resin in the conductive resin composition constituting the planar molded product is preferably 50 to 80% by volume, and the content of the conductive substance is preferably 20 to 50% by volume.

  The resin contained in the conductive resin composition is preferably a heat resistant resin, such as a polyimide resin, but may be polyether ether ketone (PEEK), polyether sulfone, or the like. A polyimide resin is a condensation polymer of diamine and tetracarboxylic dianhydride.

  The diamine for constituting the polyimide resin is preferably an aromatic diamine; examples of the aromatic diamine include paraphenylene diamine, metaphenylene diamine, 2,5-diaminotoluene, 2,6-diaminotoluene, 4, 4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-biphenyl, 3,3'-dimethoxy-4,4'-biphenyl, 2,2-bis (trifluoromethyl) -4,4'- Diaminobiphenyl, 3,3'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis- (4-aminophenyl) propane, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-di Aminodiphenyl ether, 1,5-diaminonaphthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 1,3-bis (3-aminophenoxy ) Benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy) benzene, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4- Aminophenoxy) phenyl] sulfone, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis (3-aminophenyl) 1,1,1,3,3,3-hexafluoro Examples include propane, 2,2-bis (4-aminophenyl) 1,1,1,3,3,3-hexafluoropropane and 9,9-bis (4-aminophenyl) fluorene.

  The tetracarboxylic dianhydride for constituting the polyimide resin is preferably an aromatic tetracarboxylic dianhydride; examples of the aromatic tetracarboxylic dianhydride include pyromellitic dianhydride, 1, 2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 2,2 ′ , 3,3′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic acid dihydrate, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid Dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis 2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1 -Bis (3,4-dicarboxyphenyl) ethane dianhydride, 2,2-bis [3,4- (dicarboxyphenoxy) phenyl] propane dianhydride, 4,4 '-(hexafluoroisopropylidene) diphthal Acid anhydride, oxydiphthalic anhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, bis (3,4-dicarboxyphenyl) sulfoxide dianhydride, thiodiphthalic dianhydride, 3,4,9 , 10-perylenetetracarboxylic dianhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-phenanthrenetetracarboxylic dianhydride, 9,9-bis (3 , 4-Dicarboxypheny And fluorene dianhydride, 9,9-bis [4- (3,4'-dicarboxyphenoxy) phenyl] fluorene dianhydride, and the like.

  The conductive substance contained in the conductive resin composition is dispersed in the resin. Examples of conductive substances include carbon material particles such as graphite, carbon black, carbon nanotubes, and carbon microcoils of various shapes and particle sizes, metal particles such as nickel powder and silver powder, metal alloy particles such as stainless steel powder, and tungsten carbide. And conductive particles such as intermetallic compounds such as tantalum carbide and tungsten boride, and metal-coated powders such as silver-coated carbon. The shape of the conductive material may be, for example, a fiber.

  Since the planar molded product functions as a heating element layer, the thickness thereof may be set so as to obtain a desired calorific value; the amount and type of the conductive substance contained in the planar molded product, the plate-shaped metal electrode It is preferably set according to the contact width and the like. However, as described above, the thickness of the planar molded product is preferably larger than the thickness of the plate metal.

A residue of a compound represented by the following formula (1) or formula (2) is present at the bonding interface between the plate-like metal electrode and the planar molded product. X in the formula (1) represents a phenyl group or an amino group, and Y in the formula (2) represents a methylamino group.

  The residue of the compound represented by Formula (1) or Formula (2) is a thermal decomposition product of the compound that has reacted with the plate-like metal electrode and the planar molded product as a silane coupling agent.

  The compound represented by the formula (1) and the formula (2) has a trimethoxysilyl group, a group connecting the trimethoxysilyl group and the substituents X and Y is relatively long, and includes 3 or more methylene groups. . By using such a compound as a coupling agent for adhesion between a plate-shaped metal electrode and a planar molded product containing a resin, the adhesive strength between the two can be increased; in particular, adhesion when heat generation is repeated. A decrease in strength and peeling can be suppressed.

  The planar heating element may have a reinforcing layer that covers the planar molding. The reinforcing layer preferably contains a heat resistant resin, and may be made of, for example, the same resin as the heat resistant resin contained in the planar molded product. In the case of a planar molded product, the strength of the planar heating element can be obtained by providing a reinforcing layer when the mechanical strength of the planar heating element cannot be sufficiently obtained due to the influence of the conductive material.

  The planar heating element may have an elastic layer that covers the planar molding. The elastic layer preferably contains a soft rubber having a low hardness, such as silicone rubber. More specifically, for example, silicone rubber having a JIS-A hardness of 3 to 50 degrees is suitable. The thickness of the elastic layer is preferably in the range of 100 to 500 μm. By providing the elastic layer, when the planar heating element is used as a fixing member of an image fixing device, a higher image without uneven fixing and uneven gloss can be obtained.

  The planar heating element preferably has a release layer that covers the planar molded product. The release layer is disposed on the outermost layer of the planar heating element. The release layer preferably contains a fluororesin or fluororubber, and particularly preferably contains a fluororesin. Examples of fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), etc. Or it is more preferable to mix and use. The thickness of the release layer is preferably 5 to 30 μm, and more preferably 10 to 20 μm. By providing the release layer, when the planar heating element is used as a fixing member of the image fixing apparatus, the release layer is in direct contact with the image, so that the transfer of the image to the fixing member is suppressed.

2. Manufacturing method of planar heating element The manufacturing flow of a planar heating element includes a step A of applying a compound represented by formula (1) or formula (2) to a pair of plate-like metal surfaces; A step B in which a metal sheet is set on a support material; and a process C in which a conductive resin dope is applied to the outer surfaces of the pair of plate metals and the support material to form a heat generating layer (corresponding to a planar molded product). Can be included. Furthermore, the process D which laminates | stacks a reinforcement layer, an elastic layer, and a mold release layer on a heat generating layer, and the process E which removes a support material may be included. Of course, the production method is not limited as long as the planar heating element of the present invention is obtained.

  2A to 2E show a flow for manufacturing the planar heating element 100 shown in FIG. FIG. 2A shows ring-shaped metal plates 210-1 and 210-2 to which a compound represented by formula (1) or formula (2) is applied. FIG. 2B shows a state in which ring-shaped plate metals 210-1 and 210-2 are set on a support member 300 made of a core metal. FIG. 2C shows a state in which the heat generating layer 220 is formed by applying a conductive resin dope to the support member 300 and the ring-shaped metal plates 210-1 and 210-2 shown in FIG. 2B. 2D (cross-sectional view) shows a state in which a reinforcing layer 230, an elastic layer 240, and a release layer 250 are stacked on the heat generating layer 220. FIG. FIG. 2E (sectional view) shows a state in which the support 300 is extracted from the structure shown in FIG.

  The pair of plate-like metals in the process A is a member that becomes a pair of plate-like metal electrodes in the planar heating element, for example, a ring-like member as shown in FIG. 2A, but is not particularly limited. In step A, the compound represented by formula (1) or formula (2) is applied to the surface of the plate-like metal. The compound may be applied by immersing the plate metal in the solution containing the compound or spraying the solution containing the compound on the plate metal.

  You may apply | coat the compound represented by Formula (1) or Formula (2) to a part of surface instead of the whole surface of a pair of plate-shaped metal. Specifically, the compound may be applied to at least one surface of the plate-like metal, and more specifically, the compound may be applied to the region to which the conductive resin dope is applied in Step C (region in FIG. 2A). see α and region β). The compound represented by the formula (1) or the formula (2) preferably forms a monomolecular film on the surface of the plate metal, but the coating amount is not particularly limited.

  In step B, the support material on which the pair of plate metals is set is not particularly limited as long as it has a shape capable of supporting the plate metal electrodes. The material of the support material is not particularly limited, but is a metal such as stainless steel. The support material is preferably treated with a clean and smooth surface. This is because the support material is removed in Step F.

  When the plate-shaped metal is ring-shaped, the support material is a metal core (core metal) or the like, and preferably has a diameter that allows the link-shaped plate metal to be fitted without a gap. What is necessary is just to insert a link-like plate-shaped metal in both ends of the core metal which is a support material (refer FIG. 2B).

  In step C, the conductive resin dope is applied to the surface of the support and the surfaces of the pair of plate-like metals set on the support. The conductive resin dope includes a resin or a precursor thereof, a conductive substance, and a solvent. The conductive substance contained in the conductive resin dope is the same as the conductive substance contained in the planar molded product. The resin contained in the resin dope is the same as the resin contained in the planar molded product, such as polyimide. The polyimide precursor is, for example, polyamic acid.

  Although the solvent contained in the conductive resin dope is not particularly limited, preferred examples of the solvent to be combined with the polyamic acid which is a polyimide precursor include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide. N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N-methylcaprolactam, hexamethylphosphoric triamide, 1,2-dimethoxyethane, diglyme and triglyme.

  When a conductive resin-doped coating film is formed, it is dried and further cured to form a heat generating layer. Curing is, for example, using polyamic acid as polyimide.

  Application of the conductive resin dope in step C may be performed with reference to a general manufacturing method of a fixing belt of a fixing device of an image forming apparatus. For example, the conductive resin dope may be applied using a coating apparatus shown in FIG. it can. In the coating apparatus shown in FIG. 3, the coating apparatus 9c1 includes a holding unit 9c11, a coating unit 9c12, and a curing unit 9c13.

  The holding portion 9c11 includes a first holding stand 9c111, a second holding stand 9c112, a driving motor 9c113, and a drive receiving portion 9c114. The metal core 9c2 and the holding members 9c21 and 9c22 of the metal core 9c2 are configured to be rotatable by a drive motor 9c113 and a drive receiving portion 9c114. The cored bar 9c2 corresponds to the support member 300 in FIGS.

  The coating unit 9c12 includes a coating unit 9c121 and a driving unit 9c122. The coating means 9c121 is supplied with the conductive resin dope through the conductive resin dope supply pipe 9c123, and can discharge the conductive resin dope toward the core metal 9c2 through a nozzle or the like. The application means 9c121 is attached to the guide rail 9c128 by the attachment portion 9c124.

  The curing unit 9c13 is a heating source (infrared lamp, nichrome wire, hot air device, etc.).

  The ring-shaped metal plate obtained in step B (see FIG. 2B, the support 300 corresponds to the cored bar 9c2 of the holding unit) is attached to the holding unit 9c11. While rotating the plate metal, the conductive resin dope is discharged from the coating means 9c121 moved in the direction of the rotation axis and applied to the plate metal. The coating film is heated and cured by the curing unit 9c13. Thereby, a heat generating layer is formed on the plate-like metal (see FIG. 2C).

  In step C, the conductive resin dope may be applied to the entire outer surface (exposed surface) of the plate-like metal surface set on the support, or may be applied to a part thereof. In any case, the compound represented by Formula (1) or Formula (2) in Step A is applied to the surface to which the conductive resin dope is applied. Further, in order to increase the adhesive force between the plate-like metal surface and the heat generating layer, the overlapping area between the metal surface and the heat generating layer is preferably set to a certain level or more. On the other hand, in the plate-like metal, the region where the conductive resin dope is not applied serves as a connection portion for connecting to an external device (power source or the like).

  In step D, a reinforcing layer, an elastic layer, and a release layer may be laminated on the heat generating layer. The precursor solution of each layer is applied, dried, and cured as necessary using the coating apparatus shown in FIG.

  In step E, the support material is removed to obtain a planar heating element. The support material is in contact with the pair of plate-like metal and the heat generating layer. In order to facilitate the removal of the support material, it is necessary to prevent the support material and the pair of plate-shaped metal and the heat generating layer from being fixed. Therefore, the surface of the plate-shaped metal in contact with the support material has a formula ( It may be better not to apply the compound represented by 1) or formula (2).

3. Application of planar heating element The planar heating element can be used as a member of an image fixing apparatus. The image fixing device is a device that thermally fixes an unfixed toner image, for example, in an electrophotographic image forming apparatus.

  An example of the image fixing device is shown in FIG. The image fixing device shown in FIG. 4 includes a pipe-shaped sheet heating element 400, a pressure roll 410, a shaft 420 of the pressure roll 410, a power source 430, and a lead wire 440. The shaft 420 of the pressure roll 410 is connected to a drive motor (not shown).

  The planar heating element of the present invention can be used as the planar heating element 400 of the image fixing apparatus shown in FIG. A pair of electrodes (plate metal electrodes) 450-1 and 450-2 provided at both ends of the planar heating element 400 supplies power to the heating layer of the planar heating element 400 to cause the heating layer to generate heat. In the image fixing apparatus shown in FIG. 4, the planar heating element 400 that is in pressure contact with the pressing roll 410 is rotated by the rotation of the pressing roll 410, and the pressing roll 410 and the planar heating element 400 are rotated. Copy paper on which an unfixed image is formed is sequentially fed into the nip portion, and heat fixing is performed.

[Comparative Example 1]
Preparation of electrode: A metal ring made of SUS304 having a width of 20 mm, an inner diameter of 30.05 mm, and a thickness of 50 μm was ultrasonically cleaned in acetone for 30 minutes. The washed metal ring was brought into contact with a 10% aqueous hydrochloric acid solution, etched for 10 minutes at room temperature, and washed in order of tap water and ion-exchanged water to obtain an electrode 1.

  Preparation of conductive resin dope: 18 g of graphitized carbon fiber (Nihon Graphite Fiber Co., Ltd., XN-100) is added to 100 g of polyamic acid solution (U-Vanice S301, Ube Industries, Ltd.), which is a precursor of polyimide resin, Stir and mix. Stirring and mixing were performed using a TK homodisper type 2.5 manufactured by Plymix, and the stirring and mixing conditions were 15 minutes at 5,000 rpm.

  Application of conductive resin dope: A pair of electrodes 1 was attached to both ends of a stainless steel core having a length of 380 mm and an outer diameter of 30.0 mm (see FIG. 2B). A conductive resin dope was applied to a stainless steel core bar equipped with a pair of electrodes 1 using the apparatus shown in FIG. The coating conditions were as follows, and the coating film thickness was 0.8 mm. However, it was not applied to the electrode part for power feeding.

(Condition for applying conductive resin dope)
Temperature of conductive resin dope: 25 ° C
Discharge nozzle shape: Conical nozzle Discharge nozzle diameter: 2 mm
Spacing between discharge nozzle and peripheral surface of core metal: 5 mm
Discharge amount of polyamic acid solution from discharge nozzle: 5 ml / min
Movement speed of discharge nozzle in the direction of the axis of rotation: 1mm / sec
Rotating speed of the core metal: 40 rpm (measured with HT-4200 manufactured by Ono Sokki Co., Ltd.)

  Thereafter, the coating film was heated and dried at 120 ° C. for 40 minutes while rotating at a rotation speed of 40 rpm.

  Lamination of reinforcing layer: Thereafter, a polyamic acid solution (U-Varnish S301, manufactured by Ube Industries) was applied with the apparatus shown in FIG. The coating conditions were the same as those for the conductive resin dope, and a 0.8 mm thick coating film was formed. Then, it was heated and dried at 120 ° C. for 40 minutes while rotating at a rotation speed of 40 rpm. Then, it heat-dried at 450 degreeC for 20 minute (s), and laminated | stacked the heat generating layer and the reinforcement layer.

  Preparation of elastic layer forming coating solution: Liquid rubber of silicone rubber (manufactured by Shin-Etsu Chemical Co., Ltd., KE1379) and silicone rubber (manufactured by Toray Dow Corning Silicone Co., Ltd., DY356013) are mixed at a mass ratio of 2: 1. Thus, a coating liquid for forming an elastic layer was obtained. The viscosity of the coating solution for forming an elastic layer was 50 Pa · s (temperature: 25 ° C.). The viscosity was measured with TVB10 model manufactured by Toki Sangyo Co., Ltd.

  Application of elastic layer forming coating solution: The elastic layer forming coating solution was applied onto the heat generating layer using the manufacturing apparatus shown in FIG. The application conditions were as follows. The film thickness of the elastic layer-forming coating film after drying was 200 μm. However, it was not applied to the electrode part for power feeding.

(Application conditions of the coating solution for forming the elastic layer)
Elastic layer forming coating solution temperature: 25 ° C
Shape of discharge nozzle: Conical nozzle Diameter of discharge nozzle: 2 mm
Distance between discharge nozzle and peripheral surface of heat generation layer: 5 mm
Ejection rate of the elastic layer forming coating solution from the discharge nozzle: 5 ml / min
Movement speed of discharge nozzle in the direction of the axis of rotation: 1mm / sec
Rotating speed of the core metal: 40 rpm (measured with HT-4200 manufactured by Ono Sokki Co., Ltd.)

  Thereafter, the core metal was primarily vulcanized at 150 ° C. for 30 minutes while rotating at a rotational speed of 40 rpm, and further post vulcanized at 200 ° C. for 4 hours to form an elastic layer on the heat generating layer.

  Preparation of release layer forming coating solution: PTFE resin and PFA resin mixed at a ratio of 7: 3, and a fluororesin dispersion adjusted to a solid content concentration of 45% and a viscosity of 110 mPa · s (trade name “manufactured by DuPont” 855-510 ") was prepared as a release layer forming coating solution.

  Application of release layer forming coating solution: The release layer forming coating solution was applied onto the elastic layer using the production apparatus shown in FIG. The application conditions were as follows. Then, it dried for 30 minutes at room temperature. The film thickness of the release layer-forming coating film after drying was 30 μm. However, it was not applied to the electrode part for power feeding.

(Application conditions for the release layer forming coating solution)
Temperature of the release layer forming coating solution: 25 ° C.
Discharge nozzle shape: Conical nozzle Discharge nozzle diameter: 2 mm
Distance between discharge nozzle and peripheral surface of heat generation layer: 5 mm
Discharge rate of the release layer forming coating from the discharge nozzle: 5 ml / min
Movement speed of discharge nozzle in the direction of the axis of rotation: 1mm / min
Rotating speed of the core metal: 40 rpm (measured with HT-4200 manufactured by Ono Sokki Co., Ltd.)

  Then, while rotating the cored bar at a rotational speed (circumferential speed) of 0.1 m / sec, it was heated at 230 ° C. for 30 minutes and further heated at 270 ° C. for 10 minutes to form a release layer on the elastic layer ( (See FIG. 2D).

  The formed release layer had a tensile strength of 10 MPa. The tensile strength of the release layer was measured using 5988 manufactured by Instron Japan Company Limited. The coefficient of friction (μ) of the release layer was 0.1. The coefficient of friction was measured using a portable friction meter “Muse TIPE: 94i-II (manufactured by Shinto Kagaku Co., Ltd.)”. Moreover, the measurement of the friction coefficient of the release layer was performed at 10 to 30 points set at random, and the average value thereof was taken as the friction coefficient.

  Extraction of cored bar: After forming the release layer, the cored bar was cooled and extracted to obtain a planar heating element having the configuration shown in FIGS. 1 and 2E (heat generation layer / elastic layer / release layer).

[Example 1]
Electrode 1 obtained in Comparative Example 1 was immersed in a compound represented by the following formula for 1 minute and then dried in a hot air oven for 3 minutes to obtain electrode 2. A planar heating element was obtained in the same manner as in Comparative Example 1 except that the electrode 2 was used instead of the electrode 1.

[Example 2]
Electrode 1 obtained in Comparative Example 1 was immersed in a compound represented by the following formula for 1 minute and then dried in a hot air oven for 3 minutes to obtain electrode 3. A planar heating element was obtained in the same manner as in Comparative Example 1 except that the electrode 3 was used instead of the electrode 1.

[Example 3]
Electrode 1 obtained in Comparative Example 1 was immersed in a compound represented by the following formula for 1 minute, and then dried in a hot air oven for 3 minutes to obtain electrode 4. A planar heating element was obtained in the same manner as in Comparative Example 1 except that the electrode 4 was used instead of the electrode 1.

[Comparative Example 2]
Electrode 1 obtained in Comparative Example 1 was immersed in a compound represented by the following formula for 1 minute and then dried in a hot air oven for 3 minutes to obtain electrode 5. A planar heating element was obtained in the same manner as in Comparative Example 1 except that the electrode 5 was used instead of the electrode 1.

[Comparative Example 3]
The electrode 1 obtained in Comparative Example 1 was immersed in a compound represented by the following formula for 1 minute, and then dried in a hot air oven for 3 minutes to obtain an electrode 6. A planar heating element was obtained in the same manner as in Comparative Example 1 except that the electrode 6 was used instead of the electrode 1.

(Evaluation)
The planar heating element obtained in each example and comparative example was evaluated as a heat fixing belt by the following method. The heat generating fixing belt of the image fixing device of the Konica Minolta Color MFP (bizhubC360 manufactured by Konica Minolta Business Technologies) was replaced with the sheet heating element obtained in each of Examples and Comparative Examples. Using each color multifunction device, an image with a printing rate of 5% was copied 600,000. Thereafter, the planar heating element was taken out. The resistance between the pair of electrodes of the planar heating element before the image formation and the resistance between the pair of electrodes of the planar heating element after the image formation were determined, respectively, to determine the rate of change. According to the rate of change, the following criteria were used for evaluation.
○: Resistance change is less than 5% △: Resistance change is 5% or more and less than 10% ×: Resistance change is 10% or more

  It can be seen that the rate of change in resistance before and after image formation is suppressed in the sheet heating element obtained in the example. This is presumably because the bonding state between the metal electrode and the heat generating layer did not change.

  Since the planar heating element of the present invention has a high adhesive force between the metal electrode and the heat generating layer, the metal electrode and the heat generating layer do not easily peel off even if heat generation is repeated. Therefore, the planar heating element of the present invention is suitably used as a fixing member in an image fixing device of an image forming apparatus.

DESCRIPTION OF SYMBOLS 1 1st insulating layer 2 Resistivity heating element layer 3 2nd insulating layer 4 Release layer 10 Heat generating fixing belt 100 Planar heating element 110-1,110-2 Planar metal electrode 120 Planar molding 130 Reinforcing layer 140 Elasticity Body layer 150 Release layers 210-1, 210-2 Plate metal 220 Heat generation layer 230 Reinforcement layer 240 Elastic layer 250 Release layer 300 Support body 400 Planar heat generation element 410 Pressure roll 420 Shaft 430 Power supply 440 Lead wire 9c1 Application Device 9c11 Holding portion 9c111 First holding stand 9c112 Second holding stand 9c113 Driving motor 9c114 Drive receiving portion 9c12 Coating portion 9c121 Coating means 9c122 Driving portion 9c123 Conductive resin dope supply pipe 9c124 Mounting portion 9c128 Guide rail 9c13 Curing portion 9c2 Core 9c21, 9c22 holding member

Claims (7)

A planar molded article comprising a conductive resin composition containing a conductive substance and a resin;
A pair of plate-like metal electrodes connected to the planar molding;
A planar heating element having a residue of a compound represented by the following formula (1) or the following formula (2) at an interface between the planar molded product and the plate-like metal electrode.

(X in the formula (1) represents a phenyl group or an amino group, and Y in the formula (2) represents a methylamino group)   The planar heating element according to claim 1, wherein the conductive substance is carbon material particles.   The planar heating element according to claim 1, wherein the resin is polyimide. The planar molding is a pipe-shaped molding,
The planar heating element according to claim 1, wherein each of the pair of plate-like metal electrodes has a ring shape and is connected to both ends of the pipe-shaped molded product.   The planar heating element of Claim 1 which further has an elastic body layer which covers the outer surface of the said planar molding.   The planar heating element according to claim 1, further comprising a release layer that covers an outer surface of the planar molded product. An image fixing device comprising the planar heating element according to claim 1.

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