JP2007047388A - Image heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve productivity in an image heating device that has a coil and magnetic substance core. <P>SOLUTION: The image heating device includes: a heat member 127 that heats an image t on a recording material S; a coil 4 that induction-heats the heat member; and the magnetic substance core 5 that causes a magnetic flux generated from the coil to act on the heat member. In the image heating device, a coil unit 1 is formed in such a manner that a first resin frame 3 to which the coil is fixed is joined to a second resin frame 2 to which the magnetic substance core is fixed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic heating method image heating apparatus suitable for use as an image heating fixing device mounted on an electrophotographic image forming apparatus.

  For example, an image forming apparatus using an electrophotographic method usually includes an image heating fixing device (hereinafter referred to as a fixing device) for fusing and fixing a toner image onto a recording material such as transfer paper.

  In such a fixing device, a method has been proposed in which an eddy current is generated in a conductive layer provided on the surface of the fixing roller by a magnetic flux generated by an electromagnetic induction coil, and the conductive layer is heated by Joule heat (Patent Document 1).

  In this method, since the heat generation source can be placed very close to the toner image, the temperature of the fixing roller surface becomes a temperature required for fixing when the fixing device is started, as compared with the conventional heat roller method using a halogen lamp. It has the feature that the time required to become shorter can be shortened.

  As a general configuration of the heating roller in this electromagnetic induction heating type fixing device, a heating roller having a bobbin in which an electromagnetic induction coil is spirally wound inside a heating roller made of a metal conductor is known (patent). Reference 2).

  However, when the shape of the electromagnetic induction coil is an elliptical shape with greatly different aspect ratios, it is difficult to wind the bobbin and the method of fixing the coil is a problem.

  Further, when the electromagnetic induction coil is overheated, the heating efficiency of the fixing roller may be deteriorated. For this reason, it is necessary to efficiently discharge the overheating of the electromagnetic induction coil to the outside, but the bobbin around which the coil is wound tends to accumulate heat.

Therefore, a coil unit has been proposed in which the bobbin around which the coil is wound is eliminated so that the cooling effect of the electromagnetic induction coil is increased, and the coil is fixed by sealing molding (Patent Document 3).
JP 2000-081806 A JP 2000-173759 A JP 2003-68442 A

  In the coil unit, although the electromagnetic induction coil is fixed by resin sealing to enhance the cooling effect, the magnetic core that acts on the coil and generates magnetic flux is bonded and fixed to the coil unit afterward. For this reason, in order to bond the core to the coil unit, it is necessary to take time until the coil unit is hardened, and further, it takes time to harden the adhesive in the step of bonding the core, and there is a problem that mass productivity is low. there were.

  Accordingly, an object of the present invention is to provide an image heating apparatus capable of improving productivity in an image heating apparatus having a coil and a magnetic core.

  A typical configuration of the image heating apparatus according to the present invention includes a heating member that heats an image on a recording material, a coil that induction-heats the heating member, and a magnetic core that causes magnetic flux from the coil to act on the heating member. An image heating apparatus comprising: a coil unit formed by joining a first resin frame having a coil fixed thereto to a second resin frame having a core fixed thereto. .

  According to the present invention, the cooling effect of the coil can be improved by integrating the electromagnetic induction coil with the second resin frame. Further, by integrating the magnetic core with the first resin frame, it is possible to improve the positioning accuracy and fixing reliability (durability) of the magnetic core.

  Hereinafter, the present invention will be described with reference to the drawings.

(1) Example of Image Forming Apparatus FIG. 15 is a schematic configuration model diagram of an example of an image forming apparatus provided with a coil unit according to the present invention in a fixing device. The image forming apparatus 100 of this example is a laser beam printer using a transfer type electrophotographic process. Since this printer itself belongs to the public domain, its description will be briefly described.

  Reference numeral 121 denotes an original platen glass, on which an original O is placed with a predetermined placement reference with the image surface to be printed face down, and is placed with the original retainer plate 122 covered. The downward image surface of the set original is photoelectrically read by the operation of the image reading unit 123.

  Reference numeral 101 denotes an electrophotographic photosensitive drum (hereinafter referred to as a photosensitive drum) that is rotationally driven in a clockwise direction indicated by an arrow at a predetermined peripheral speed. The photosensitive drum 101 is subjected to uniform charging processing of a predetermined polarity and potential by the charger 102, and the charging processing surface is subjected to laser scanning exposure by an image writing unit (laser scanner) 103, thereby corresponding to a laser scanning exposure pattern. The electrostatic latent image is formed.

  The image writing unit 103 generates modulated laser light corresponding to the image data based on a command from a controller (not shown) based on the image data read by the image reading unit 123 or based on input image data from an external device. The photosensitive drum surface is output for scanning exposure.

  The electrostatic latent image formed on the surface of the photosensitive drum 101 is developed as a toner image by the developing device 104. Then, in the transfer portion where the toner image is a facing portion between the photosensitive drum 101 and the transfer device 105, a recording material (transfer material, paper) S fed to the transfer portion from the paper supply portion side at a predetermined control timing. Are sequentially transferred to the surface.

  The recording material S, which has been transferred from the surface of the photosensitive drum 101 after receiving the transfer of the toner image at the transfer unit, is transported by the transport device 107 and introduced into the fixing device 108, where the toner image is subjected to heat and pressure fixing processing. The paper is discharged onto a paper discharge tray 110 by a paper discharge roller 109. The fixing device 108 is an electromagnetic induction heating type device. The fixing device 108 will be described in detail in the next section (2).

  On the other hand, the surface of the photosensitive drum 101 after the separation of the recording material is cleaned by removing residual deposits such as transfer residual toner by the cleaning device 106 and repeatedly used for image formation.

  Reference numerals 111a, 111b, 111c, and 111d denote first to fourth paper feed cassette paper feed units, and 111e denotes a manual paper feed unit. The recording material S is separated and fed from one of these paper feeding sections by the pickup roller 112, conveyed through the sheet path to the registration roller pair 113, and a predetermined control timing is supplied to the transfer section by the registration roller pair 113. It is fed at.

  In the double-sided printing mode, the recording material printed on the first surface (single-sided) that has exited the fixing device 108 is routed to the sheet path 115 side by the flapper 114 whose posture has been switched, and is discharged onto the intermediate tray 116 and stacked. The The recording material on the intermediate tray 116 is re-fed by the single sheet separation and re-feeding mechanism 117 and reaches the registration roller pair 113 through the reverse sheet path 118. The recording material is fed to the transfer portion by the registration roller pair 113 at a predetermined control timing, whereby the toner image is transferred onto the second surface of the recording material. Thereafter, the paper is discharged onto the paper discharge tray 110 through the path of the conveying device 107, the fixing device 108, and the paper discharge roller 109, as in the first-side print mode.

(2) Fixing device 108
FIG. 1 is an enlarged schematic cross-sectional view of the main part of the fixing device 108. The fixing device 108 is an electromagnetic induction heating type heat roller type device.

  Reference numeral 127 denotes a hollow pipe-shaped fixing roller made of a metal conductor (electromagnetic induction heat generating member) as a heating member, and a toner release layer 127a is provided on the outer peripheral surface. The fixing roller 127 is disposed such that both ends thereof are rotatably supported via a bearing member between unillustrated device side plates.

  Reference numeral 128 denotes an elastic pressure roller (hereinafter referred to as a pressure roller) as a pressure member. The pressure roller 128 includes an iron core 128a, a silicone rubber layer (heat-resistant elastic layer) 128b concentrically provided around the outer periphery of the core, and a toner separation provided on the outer peripheral surface of the silicone rubber layer. A mold layer 128c. The both ends of the cored bar 128a are rotatably supported between the apparatus side plates (not shown) via a bearing member, and the bearing member is pushed up and biased by a biasing member (not shown) toward the fixing roller 128. As a result, a nip portion (fixing nip portion) N is formed between the fixing roller and the fixing roller. That is, the pressure roller 128 is pressed against the lower surface of the fixing roller 127 with a predetermined pressing force against the elasticity of the silicone rubber layer 128b. Thereby, the press-contact nip portion N having a predetermined width is formed by the elastic strain of the silicone rubber layer 128b.

  A fixing roller gear (not shown) is integrally provided on one end side of the fixing roller 127, and a rotational force is transmitted to the gear from a driving system (not shown) so that the fixing roller rotates in a clockwise direction indicated by an arrow A with a predetermined circumference. It is rotationally driven with speed. The pressure roller 128 rotates in the counterclockwise direction indicated by an arrow B following the rotational driving of the fixing roller 127.

  Reference numeral 1 denotes an electromagnetic induction coil unit (hereinafter referred to as a coil unit) which is a magnetic flux generating means, which is inserted into the fixing roller 127 and fixedly disposed non-rotatingly. The coil unit 1 includes a first frame 2 integrated with a magnetic core (hereinafter referred to as a core) 5, and a second frame 3 integrated with an electromagnetic induction coil (hereinafter referred to as a coil) 4. Is an assembly having a basic configuration. The configuration of the coil unit 1 will be described in detail in the next section (3).

  An eddy current is generated in the fixing roller 127 made of a metal conductor (electromagnetic induction heating member) by the action of a high-frequency magnetic flux generated by a high-frequency current flowing from an excitation circuit (not shown) to the coil 4 in the coil unit 1. Is generated, and the fixing roller is heated by electromagnetic induction by Joule heat. The temperature increase of the fixing roller 127 is detected by a temperature detection element (not shown), and power is supplied from the excitation circuit to the coil 4 so that the temperature of the fixing roller is maintained at a predetermined fixing temperature (target temperature). Be controlled.

  The recording material S carrying the unfixed toner image t is introduced into the fixing nip portion N in a state where the fixing roller 127 is rotated and the temperature of the fixing roller is controlled to a predetermined fixing temperature. Then, the recording material S is nipped and conveyed in the fixing nip portion N in the direction indicated by the arrow X, and in the nipping and conveying process, the toner image t is heated by the heat of the fixing roller 127, and the pressure of the fixing nip portion is received and the heat pressure is increased. It is fixed.

  Reference numeral 130 denotes a separation claw that suppresses the recording material S from being wound around the fixing roller 127 and serves to separate the recording material from the fixing roller.

(3) Coil unit 1
2 is a perspective view of the first frame 2 integrated with the core 5, FIG. 3 is a perspective view of the first frame 2 viewed from the side opposite to the core 5, and FIG. 4 is a second view integrated with the coil 4. It is a perspective view of the frame 3.

  The first frame 2 that is the second resin frame is a resin member that is elongated in a direction orthogonal to the conveyance direction X (FIG. 1) of the recording material S, and a core holding portion 2a having a substantially T-shaped cross section; And a plurality of ribs 2 b protruding from the core holding portion in the radial direction of the fixing roller 127. The first frame (hereinafter referred to as the first frame) is a hole in the longitudinal both ends of the core holding portion 2a, and a round hole 8 and a long hole for fastening the screw with the second frame 3 which is the first resin frame. 9 (FIG. 3). Moreover, it has the nail | claw 10 for joining to the 2nd flame | frame 3 on the outer side surface of the core holding | maintenance part 2a (FIG. 2). An insulating resin is used as the resin of the first frame 2. As the insulating resin, a liquid crystal polymer resin, a polyphenylene sulfide resin, a phenol resin, or the like is used.

  The core 5 is formed in a T-shaped cross section with 18 side cores 5a and 10 center cores 5b (FIG. 1), and the end portions of the side core and the center core on the side core side are covered with the core holding part 2a. Thus, it is integrated with the first frame 2 (FIGS. 6 and 7). As a material of the core 5, a material having a high magnetic permeability residual density such as ferrite may be used, but any material that can generate a magnetic flux is used and is not particularly defined.

  The second frame (hereinafter referred to as a second frame) 3 includes a coil holder (hereinafter referred to as a holder) 19 as a molded body that supports the coil 4 and a sealing member 21 (see FIG. 4). The holder 19 and the sealing member 21 are members made of resin elongated in a direction orthogonal to the conveyance direction X of the recording material S. As the resin of the second frame 3, the same insulating resin as that of the first frame 2 is used.

  The holder 19 is formed in a substantially semicircular cross-sectional shape along the inner peripheral surface of the fixing roller 127 (FIG. 1), and is a core support portion that protrudes toward the center core side substantially at the center of the inner peripheral surface on the center core 5b side. 19a (FIG. 4). The holder 19 has a hole 20 for joining the first frame 2 on the inner longitudinal side. The holder 19 has a claw 22 for coupling to the sealing member 21 on the inner longitudinal side and the outer longitudinal side of the core support portion 19a.

  The coil 4 must generate an alternating magnetic flux sufficient for heating. For this purpose, it is necessary to have a low resistance component and a high inductance component. As a core material of the coil 4, a litz wire obtained by bundling approximately 80 to 160 fine wires of Φ0.1 to 0.3 is used. Insulated coated wires are used for the thin wires. The coil 4 is a wound coil that is wound a plurality of times along the inner peripheral surface of the holder so as to go around the free end of the center core 5b that is inserted into and supported by the core support portion 19a of the holder 19. (FIG. 1), the shape is an elliptical shape with greatly different aspect ratios. Thus, the coil 4 is supported on the inner peripheral surface of the holder 19 on the center core 5b side. Reference numerals 4a and 4b denote power supply lead wires connected to the coil 4, respectively, and are drawn out from the end of the holder 19 to the outside.

  The sealing member 21 is formed in a substantially semicircular cross section along the coil 4 and covers the coil 4 supported by the holder 19 on the first frame 2 side and is coupled to the claw 22 of the holder (FIG. 6). ). Thus, the coil 4 is integrated with the holder 19 and the sealing member 21. The claw 22 of the holder 19 has not only a role of coupling with the sealing member 21 but also a role of suppressing a reaction force from the coil 4. In FIG. 6, the claw 22 on the long side surface inside the holder 19 is omitted. Further, the sealing member 21 has a portion 21a that covers the coil 4 and a portion 21b that does not cover the coil 4 (FIG. 5). Further, the sealing member 21 has parts 29 in which female screws are processed on the inside for screw fastening to the first frame 2 at positions corresponding to the round holes 8 and the long holes 9 of the first frame 2 at both longitudinal ends. .

  The first frame 2 integrated with the core 5 and the second frame 3 integrated with the coil 4 are assembled as shown in FIG. 5 is a perspective view of the coil unit 1, FIG. 6 is an enlarged cross-sectional view of the coil unit 1 taken along line VI-VI in FIG. 5, and FIG. 7 is an enlarged cross-sectional view of the coil unit 1 taken along line VII-VII in FIG. is there. The assembly of the first frame 2 integrated with the core 5 and the second frame 3 integrated with the coil 4 will be described in the next section (4).

(4) Manufacturing Method of Coil Unit 1 a) First Step In the first step, the first frame 2 integrated with the core 5 is composed of 28 cores (18 side cores 5a, 10 center cores 5b). Is manufactured by insert molding.

  FIG. 8 shows a structure of a mold used for manufacturing the first frame 2.

  First, the core 5 is heated to a temperature of 150 ° C. or higher and 230 ° C. or lower in a furnace (not shown). The cavity mold 11 and the core mold 14 constituting the mold are opened, and the heated cores 5a and 5b are set in the cavity mold and the core mold. At this time, the center core 5 b is inserted into the gap portion 12 dug in the cavity mold 11. A magnet 13 is embedded in the gap portion 12, and the center core is held in the mold by the magnetic force of the magnet. The cavity mold 11 and the core mold 14 are both made of a nonmagnetic metal. The side core 5 a is attached by fitting a hole 5 a 1 provided in the side core and a pin 15 protruding from the core mold 14. As a result, the center core 5b is aligned with the cavity mold 11 and the position accuracy of the center core is improved. Further, the pin 16 protrudes also from the cavity mold 11, and when the cavity mold 11 and the core mold 14 are closed, the side core 5 a is completely removed by the pins 15 and 16 of both the cavity mold and the core mold 14. It will be retained. Thereby, the side core 5a is arranged with good alignment with respect to the mold cavity 11 and the core mold 14, and the positional accuracy of the side core 5a is improved. The pin 16 protruding from the cavity mold 11 can be expanded and contracted by a spring 17 within the tolerance of the thickness of the side core 5a, so that the difference in thickness of the side core can be absorbed.

  The mold cavity 11 and the core mold 14 are closed, and a liquid resin is poured into the gap 18 formed in the cavity mold and the core mold corresponding to the form of the first frame 2 by injection molding. This liquid resin is an insulating resin, such as a liquid crystal polymer resin, a polyphenylene sulfide resin, or a phenol resin. The first frame 2 integrated with the core 5 is manufactured by solidifying the liquid resin (FIG. 9). And the round hole 8 and the elongate hole 9 (FIG. 3) are formed in the longitudinal both ends of the core support part 2a of the 1st flame | frame 2, respectively.

b) Second Step In the second step, the holder 19 is manufactured by a well-known injection molding. FIG. 10 shows a perspective view of the holder 19. As shown in FIG. 10, the holder 19 includes a hole 20 for joining with the first frame 2 and a claw 22 for joining with the sealing member 21. The liquid resin used for molding the holder 19 is the same resin as the liquid resin used to manufacture the first frame 2.

  Next, the second frame 3 in which the coil 4 is integrated is manufactured.

  FIG. 11 is a perspective view of the holder 19 that supports the coil 4.

  First, the coil 4 is heated to a temperature of 150 ° C. or higher and 230 ° C. or lower in a furnace. After that, the heated coil 4 as shown in FIG. 12 is assembled in the holder 19 and set in a mold, and then the resin is poured.

  12A and 12B show the structure of a mold used to manufacture the second frame 3 integrated with the coil 4. FIG.

  The cavity mold 24 and the core mold 25 constituting the mold are opened, and the holder 19 incorporating the heated coil 4 is set in the core mold 25. When the cavity mold 24 and the core mold 25 are closed, the coil 4 is held at a desired position by the coil holding piece 23 in the cavity mold 24 as shown in FIG. Thereby, the coil 4 is fixed to the holder 19 during the molding process.

  And liquid resin is poured by injection molding with respect to the space | gap part 26 formed between the cavity metal mold | die 24 and the core metal mold | die 25 corresponding to the form of the sealing member 21 like (b). This liquid resin is the same resin as the liquid resin used for manufacturing the first frame 2. The second frame 3 integrated with the coil 4 is manufactured by solidifying the liquid resin (FIG. 13). The poured resin covers the coil 4 and is combined with a claw 22 provided in the holder 19 to form a sealing member 21 integrated with the holder. At this time, the coil holding piece 23 of the cavity mold 24 forms a portion 21b (a recess having no resin) (FIG. 4) that does not cover the coil 4. That is, by pouring liquid resin, the part which covers the coil 4 with resin, and the part which is not covered coexist.

  In the molding process of the second frame 3, a part 29 (FIG. 4) in which the female screws at both ends of the sealing member 21 in the cavity mold 24 and the core mold 25 are processed (knurled on the outside) is also insert-molded. Is done. In addition, after the molding of the sealing member 21, the part 29 in which the female screw is processed can be inserted later by hot press fitting.

  In the molding of the second frame 3 described above, the slide mechanism 28 is provided in the core mold 25 so that the second frame is not taken to the side of the mold 24 as shown in FIG. The slide mechanism 28 has a structure in which the die is opened from the closed state and the tip of the holder 19 is held by the slider 28a until the runner 27 is cut from the second frame, and the slider moves after the runner is cut. . The pin 28b is fixed to a fixed block 28c on the side of the mold 24.

c) Third Step Finally, the first frame 2 integrated with the core 5 and the second frame 3 integrated with the coil 4 are joined.

  FIG. 14 is an explanatory diagram when the first frame 2 and the second frame 3 are joined.

  As shown in FIG. 14, using the components 29 provided at both longitudinal ends of the sealing member 21 of the second frame 3 and the holes 8 and the elongated holes 9 provided at both longitudinal ends of the first frame 2, The first frame and the second frame 3 are joined by fastening with screws 30. As the screw 30, a stepped screw is used, and a spring washer 31 as a washer is inserted between the stepped screw 30 and the first frame 2. Further, the first frame 2 and the second frame 3 are also joined by locking a claw 10 (FIG. 2) provided in the first frame 2 and a hole 20 (FIG. 4) provided in the second frame 3. (FIG. 6).

  According to the coil unit 1 of the present embodiment, the following effects can be obtained.

  1) By fixing the core and the coil in separate frames, the time required for fixing in each step can be performed in parallel, the working time can be shortened, and the mass productivity can be improved. Furthermore, the work process can be simplified.

  2) By integrating the coil 4 with the second frame 3, the coil cooling effect can be improved. That is, heat generated in the coil 4 during use of the coil unit 1 can be released through the second frame 3. Further, by integrating the core 5 with the first frame 2, the positioning accuracy of the core and the reliability (durability) of fixing can be improved. That is, the core 5 can be held in a mold into which a liquid resin is poured, and the first frame is molded with the core positioned. Thereby, the positioning accuracy of the core 5 with respect to the first frame 2 is improved. In addition, since it is not necessary to attach the core 5 with an adhesive, the reliability (durability) of fixing the core to the first frame 2 can be improved.

  3) Since the process of manufacturing the first frame 2 integrated with the core 5 and the process of manufacturing the second frame 3 integrated with the coil 4 are separate processes, reduction of resin used for integration And the coil unit 1 can be reduced in weight. Thereby, productivity improvement and cost reduction of the coil unit 1 were attained.

  4) In the first step, before pouring the liquid resin, the magnetic core is heated to a temperature of 150 ° C. or higher and 230 ° C. or lower, so that the temperature difference from the liquid resin is reduced and the first frame is reduced. 2 The internal stress after molding is reduced. As a result, the durability of the first frame 2 could be improved. When the core 5 is reserved at the above temperature, the effect is small if the core temperature is lower than 150 ° C., and the productivity may be impaired if the temperature exceeds 230 ° C.

  5) In the second step, when the holder 19 and the coil 4 are integrated by pouring a liquid resin, the portion 21a that covers the coil 4 with the resin and the portion 21b that does not cover the coil 4 coexist. Accordingly, when the temperature of the coil 4 rises during use of the coil unit 1, a linear expansion coefficient difference is generated between the holder 19 and the sealing member 21 covering the coil 4. However, the presence of the portion 21b that does not cover the coil 4 in the sealing member 21 makes it possible to absorb the difference in linear expansion coefficient at that portion. That is, the portion 21b that does not cover the coil 4 with the resin can absorb the thermal expansion in the longitudinal direction of the coil 4 and suppress the displacement of the coil.

  6) In the second step, the temperature difference from the liquid resin is reduced by heating the coil 4 to a temperature of 150 ° C. or higher and 230 ° C. or lower before pouring the liquid resin into the second frame 3. The internal stress after formation becomes small. Thereby, the durability of the second frame 3 could be improved. Therefore, the durability of the coil unit 1 can be improved in combination with the improvement of the durability of the first frame 2 in the above (3). When the coil 4 is preliminarily set at the above temperature, the effect is small when the coil temperature is lower than 150 ° C., and the productivity may be impaired when the temperature exceeds 230 ° C.

  7) In the first step, a round resin 8 and a long hole 9 are formed at both longitudinal ends of the first frame 2 by pouring a liquid resin. In the second step, liquid resin is poured to form portions 29 in which female threads are processed at both longitudinal ends of the second frame 3. As a result, the screws 30 can be used for joining the first frame 2 and the second frame 3. As a result, the bonding strength was increased as compared with bonding methods such as welding or self-tapping.

  8) Since the second step includes a step of inserting a part in which the female screw is processed at both longitudinal ends of the second frame 3, the part 29 in which the female screw is processed is held in the mold for injection molding. This part can be fixed by the resin after molding. As a result, compared to inserting the component 29 by hot press-fitting or the like after the second frame 3 is molded, it is possible to fix the component on which the female screw is processed with high accuracy and strength.

  9) In the third step, the screw used for joining the first frame 2 and the second frame 3 is a stepped screw 30, and a spring washer 31 is inserted between the stepped screw and the first frame, and the first frame And the second frame are joined. A clamping force is generated between the first frame 2 and the second frame 3 by a spring washer 31 inserted into the stepped screw 30 and is coupled. In addition, since the coil unit 1 generates thermal stress in the first frame 2 and the second frame 3 due to heat received from the fixing roller 127 during use, stress is generated in the joint portion. The stress is reduced by the spring washer 31.

  10) Since the first and second frames 2 and 3 are made of the same insulating resin, the insulating property of the coil unit 1 can be guaranteed. Further, since the first frame 2 and the second frame 3 are made of the same material, it is possible to reduce the thermal stress caused by the difference in linear expansion coefficient that occurs when the coil unit 1 is used.

  11) When the resin of the first and second frames 2 and 3 is a liquid crystal polymer resin, it is possible to provide the coil unit 1 that is insulating and has high heat resistance and high rigidity.

  12) When the resin of the first and second frames 2 and 3 is a polyphenylene sulfide resin or a phenol resin, an inexpensive coil unit 1 that is excellent in insulation, high heat resistance, and high rigidity can be provided.

[Others]
The image heating apparatus of the present invention is not limited to the use of the embodiment, but is used as an image heating apparatus that heats a recording material carrying an image to improve surface properties (such as gloss) and an image heating apparatus that is supposed to be worn. Can do.

Expanded cross-sectional model view of the main part of the fixing device Perspective view of the first frame integrated with the core A perspective view of the first frame viewed from the side opposite to the core Perspective view of second frame integrated with coil Coil unit perspective view Enlarged sectional view of the coil unit taken along line VI-VI in FIG. The expanded sectional view which follows the VII-VII line in FIG. 5 of a coil unit. Structural drawing of the mold used to manufacture the first frame Cross section of the first frame integrated with the core Perspective view of holder Perspective view of the holder that supports the coil Structural drawing of the mold used to manufacture the second frame integrated with the coil Cross section of the second frame integrated with the coil Explanatory drawing when joining the first frame and the second frame Schematic model diagram of an example of an image forming apparatus

Explanation of symbols

1: coil unit, 2: first frame, 3: second frame, 4: electromagnetic induction coil, 5: magnetic core, 5a: side core, 5b: center core, 8: round hole, 9: long hole, 19: Coil holder, 20: hole, 21: sealing member, 22: claw, 29: parts with internal thread processed inside (knurled on the outside), 30: stepped screw, 31: spring washer

Claims (4)

In an image heating apparatus having a heating member for heating an image on a recording material, a coil for inductively heating the heating member, and a magnetic core for causing a magnetic flux from the coil to act on the heating member,
An image heating apparatus, wherein a coil unit is formed by joining a first resin frame to which a coil is fixed to a second resin frame to which a magnetic core is fixed.   2. The image heating apparatus according to claim 1, wherein the surface of the coil is bonded to the surface of the second resin frame in the longitudinal direction.   The image heating apparatus according to claim 2, wherein the second resin frame includes a portion that covers the coil and a portion that does not cover the coil in a longitudinal direction of the coil. In an image heating apparatus comprising: a heating member that heats an image on a recording material; a coil that induction-heats the heating member; and a resin holder that is integrally formed so as to adhere to the coil and accommodates the coil.
The image heating apparatus according to claim 1, wherein the resin holder is provided with a recess that absorbs thermal expansion in the longitudinal direction of the coil and suppresses displacement of the coil.