Such as heating devices, image forming devices

Abstract

To provide an image heating device in which heat transmission to the junction of a heater and an electric wire is suppressed.SOLUTION: Provided is an image heating device comprising a film, a heater 300 that has a heat generating element, a support member 240 that supports the heater 300, a roller that forms a nip part between the film and itself, and an electric wire 601 that is joined to the heater 300 by an adhesive 400 and is electrically connected to the heater 300, wherein a heat conduction member 500 is further included that is in contact with the heater 300 and the support member 240. The heater 300 has a first region L1 in which the heating element is provided, a second region L2 in which the adhesive 400 is provided, and a third region L3 between the first region L1 and the second region L2. On a plane of the heater 300 that faces the seating face of the support member 240, and which is a plane of the third region L3, there exists a region that is not in contact with the support member 240, and the heat conduction member 601 is in contact with the heater 300 and the support member 240 in either the second region L2 or the third region L3 of the heater 300.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an image heating apparatus such as a fixing apparatus mounted on an image forming apparatus such as a copying machine or a printer using an electrophotographic system or an electrostatic recording system, or a gloss imparting apparatus that improves the glossiness of a toner image by reheating a fixed toner image on a recording material. The present invention also relates to an image forming apparatus provided with the image heating apparatus.

Background Art

[0002] Conventionally, as an image heating apparatus mounted on an image forming apparatus such as a copying machine or a printer, there is a fixing apparatus having a film that transfers heat to a recording material, a heater that contacts the inner surface of the film, and a roller that forms a nip portion with the film. As an example of such an image heating apparatus, Patent Document 1 discloses a heater in which a plurality of heat generating blocks are arranged side by side along the longitudinal direction of the heater on a base plate of the heater, and a temperature detection element is provided for each of the heat generating blocks.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration described in the above-mentioned Patent Document 1, as electric wires connecting the heater and the control board, FPC (Flexible Printed Circuit) and FFC (Flexible One possibility is to use a flexible sheet such as a flat cable. Alternatively, the electrical contacts between the flexible sheet and the heater can be joined with solder. In this case, as the heater heats up and stops, the solder joint in contact with the heater is repeatedly heated and cooled. In particular, in structures where the heating rate is fast, such as a configuration in which a non-contact area with the heater is provided on the heater seat surface of the heater support member, the joint also heats up rapidly, making it easy for thermal fatigue to accumulate at the joint. If thermal fatigue accumulates at the joint and cracks occur, problems such as electrical connection breakage or the flexible sheet peeling off may occur.

[0005] The objective of the present invention is to provide an image heating device that suppresses heat transfer to the joint between the heater and the electric wire. [Means for solving the problem]

[0006] To solve the above problems, the image heating apparatus of the present invention is A cylindrical film and A heater having a heating element, which is elongated in the direction of the generatrix of the film and is arranged in the internal space of the film along the direction of the generatrix of the film, A support member is arranged in the internal space of the film and supports the heater, A roller that is in contact with the outer surface of the film and forms a nip portion that sandwiches the recording material between itself and the film, The heater and solder It is joined and electrically connected to the heater. FPC and, An image heating device comprising the nip portion, which heats the image formed on the recording material while transporting the recording material, The heater is bonded to the support member with an adhesive. The heater has a first region in the busbar direction on which the heating element is provided, and solder A second region is provided, and a third region is located between the first and second regions. a third region in which neither the heating element nor the solder is provided. and, In the transport direction of the recording material perpendicular to the aforementioned busbar direction, the third region Opposite the seating surface of the support member The surface is, Not in contact with the support member contactless region Having , The adhesive is provided in the non-contact area and in contact with the heater and the support member, and in the direction of the generatrix. at least one of the second region and the third region of the heater It is located It is characterized by the following: [Effects of the Invention]

[0007] With the above configuration, the present invention provides an image heating device that suppresses heat transfer to the joint between the heater and the electric wire. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view of the image forming apparatus according to Example 1. [Figure 2] This is a schematic diagram of the fixing device according to Example 1. [Figure 3] This is a diagram of the heater's configuration. [Figure 4] This is a diagram showing the configuration of the heater support member and the heater. [Figure 5] This shows the temperature change at the solder joint. [Modes for carrying out the invention]

[0009] The embodiments for carrying out this invention will be described in detail below with reference to the drawings, based on examples. However, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments should be appropriately modified depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of this invention is not intended to be limited to the following embodiments.

[0010] <Example 1> (Image forming apparatus 100) First, the schematic configuration of an image forming apparatus 100 according to the present embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view of the image forming apparatus 100 which is a laser printer using electrophotographic recording technology. When the image forming apparatus 100 receives a print signal, a scanner unit 21 emits laser light modulated in accordance with image information, and scans a photoconductor 19 charged to a predetermined polarity by a charging roller 16. As a result, an electrostatic latent image is formed on the photoconductor 19. Toner is supplied from a developing roller 17 to this electrostatic latent image, and a toner image corresponding to the image information is formed on the photoconductor 19. After the toner image is transferred to a recording material P, the photoconductor 19 is cleaned by a cleaner 18.

[0011] The recording material P stacked on a paper feed cassette (paper feed unit) 11 is fed one by one by a pickup roller 12, and conveyed toward a registration roller 14 by a roller 13. Further, the recording material P is conveyed from the registration roller 14 to a transfer position in synchronization with the timing at which the toner image on the photoconductor 19 reaches the transfer position formed by the photoconductor 19 and a transfer roller 20. While the recording material P passes through the transfer position, the toner image on the photoconductor 19 is transferred to the recording material P. After that, the recording material P is heated by a fixing device 200, and the toner image is heat-fixed to the recording material P. The fixing device 200 serving as an image heating device is supplied with electric power from a control circuit 40 serving as a control unit connected to a commercial AC power supply 41. The recording material P carrying the fixed toner image is discharged to a tray at the upper part of the image forming apparatus 100 by rollers 26 and 27.

[0012] The above-described photoconductor 19, charging roller 16, scanner unit 21, developing roller 17, and transfer roller 20 constitute an image forming unit that forms an unfixed image on the recording material P. Further, a cartridge 15 including the photoconductor 19, charging roller 16, developing roller 17, and cleaner 18 is detachably attachable to the image forming apparatus 100 as a replacement unit.

[0013] (Fixing Device 200) Next, a schematic configuration of a fixing device 200, which is a fixing portion that fixes an image formed on a recording material P to the recording material P, will be described with reference to Figs. 2(a) and 2(b). Fig. 2(a) is a schematic cross-sectional view of the fixing device 200 of the present embodiment. The fixing device 200 includes: a fixing film 210 as a heating rotary member, a heater 300 having a contact surface S1 that faces and contacts the inner surface of the fixing film 210, and a pressure roller 220 as a pressure rotary member that forms a fixing nip portion N between itself and the fixing film 210. The fixing nip portion N of the present embodiment is formed by the heater 300 and the pressure roller 220 via the fixing film 210, and the contact surface S1 of the heater 300 serves as a nip portion forming surface. Further, on the side opposite to the contact surface S1 with the inner surface of the fixing film 210, a heater support member 240 is provided as a support member that supports the heater 300. The metal stay 250 is disposed in contact with the surface of the heater support member 240 on the side opposite to the seating surface that supports the heater 300, and is urged toward the pressure roller 220 by a pressure mechanism (not shown). The fixing nip portion N is formed by this urging force.

[0014] The fixing film 210 is a cylindrical multi-layer heat-resistant film, and a heat-resistant resin such as polyimide with a thickness of about 50 to 100 μm, or a metal such as stainless steel with a thickness of about 20 to 50 μm can be used as the base layer. The surface of the fixing film 210 is coated with a heat-resistant resin to prevent toner adhesion and ensure separability from the recording material P, which forms releasability. As the heat-resistant resin, for example, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or the like with a thickness of about 10 to 50 μm can be used. Further, particularly in an apparatus for forming color images, a heat-resistant rubber such as silicone rubber with a thickness of about 100 to 400 μm and a thermal conductivity of about 0.2 to 3.0 W / m·K may be provided as an elastic layer between the base layer and the release layer to improve image quality.

[0015] In the present embodiment, from the viewpoints of thermal responsiveness, image quality, durability, and the like, polyimide with a thickness of 60 μm is used as the base layer of the fixing film 210, silicone rubber with a thickness of 300 μm and a thermal conductivity of 1.6 W / m·K is used as the elastic layer, and PFA with a thickness of 30 μm is used as the release layer.

[0016] The pressure roller 220 has a core metal 221 made of a material such as iron or aluminum, and an elastic layer 222 made of a material such as silicone rubber. The heater support member 240 also has a guide function that contacts the inner surface of the fixing film 210 and guides the rotation of the fixing film 210. The pressure roller 220 receives power from the motor 30 and rotates in the direction of arrow R1. Since the pressure roller 220 is in contact with the outer surface of the fixing film 210, the fixing film 210 rotates in the direction of arrow R2 as the pressure roller 220 rotates. The recording material P, which is held between the pressure roller 220 and the fixing film 210, is then conveyed in the conveying direction as they rotate. At the fixing nip section N, the unfixed toner image T on the recording material P is fixed by applying heat from the fixing film 210 while the recording material P is held and conveyed.

[0017] The heater 300 is a ceramic heater having a ceramic substrate 305 and a heating element 302 provided on the substrate 305, and heats the fixing film 210 with heat emitted by the heating element 302. The heater 300 in this embodiment is an elongated member in the width direction of the recording material P and in a direction parallel to the rotation axis direction (general direction) of the pressure roller 220 and the fixing film 210, and is arranged in the internal space of the fixing film 210. The heater 300 has a surface protection layer 308 provided on the side of the fixing nip portion N and a surface protection layer 307 provided on the side opposite to the fixing nip portion N. As will be described in detail later, the surface of the heater 300 opposite to the surface facing the fixing nip portion N is provided with a plurality of electrodes E electrically connected to a plurality of heating elements 302, and the fixing device 200 is provided with a plurality of electrical contacts C that contact the plurality of electrodes E of the heater 300. Figure 2(a) shows electrode E4 and electrical contact C4 as representative examples.

[0018] Figure 2(b) is an enlarged view of the vicinity of the heater 300 in Figure 2(a). The heater 300 is in contact with the heater support member 240 on the side opposite to the contact surface S1 with the fixing film 210. It has a contact area S2. It also has a non-contact area S3 that does not come into contact with the heater support member 240. As will be described in detail later, in the non-contact area S3, nothing other than the adhesive and electrodes comes into contact with the heater 300, so heat is not easily transferred from the heater 300 to the heater support member 240.

[0019] (Heater 300) Next, the detailed configuration of the heater 300 will be described with reference to Figures 3(a) and 3(b). Figure 3(a) is a schematic cross-sectional view showing the layer configuration of the heater 300 according to this embodiment, and Figure 3(b) is a configuration diagram showing the configuration of each layer of the heater 300. Figure 3(a) shows a cross-section near the transport reference position X shown in Figure 3(b). The transport reference position X is defined as the reference position when transporting the recording material P. In this embodiment, the recording material P is transported such that the central part of the recording material P is aligned with the transport reference position X in the width direction of the recording material P, which is perpendicular to the transport direction of the recording material P.

[0020] The surface protection layer 308 that slides against the fixing film 210 on the substrate 305 can be broadly classified into sliding surface layer 1 and sliding surface layer 2, in order from the substrate 305 side, based on its layer structure. Similarly, the surface protection layer 307, which is provided on the side of the substrate 305 opposite to the surface protection layer 308, can be broadly classified into back surface layer 1 and back surface layer 2, in order from the substrate 305 side, based on its layer structure. Details of each layer structure will be described later.

[0021] The heater 300 has a first conductor 301 and a second conductor 303 provided on the back surface side of the back layer 1. The first conductor 301 (301a, 301b) is provided along the longitudinal direction of the heater 300. The first conductor 301 is provided separately as a conductor 301a located on the upstream side and a conductor 301b located on the downstream side in the transport direction of the recording material P. The second conductor 303 (303-4 near the transport reference position X) is provided along the longitudinal direction of the heater 300 at a different position from the first conductor 301 in the short direction perpendicular to the longitudinal direction of the heater 300.

[0022] Between the first conductor 301 and the second conductor 303, a heating element 302 is provided, which generates heat due to the power supplied via the first conductor 301 and the second conductor 303. In this embodiment, the heating element 302 is separated into a heating element 302a (302a-4 near the transport reference position X) located upstream in the transport direction of the recording material P, and a heating element 302b (302b-4 near the transport reference position X) located downstream.

[0023] Furthermore, an insulating (glass in this embodiment) surface protection layer 307 is provided on the back surface layer 2 of the heater 300, covering the heating element 302, the first conductor 301, and the second conductor 303 (303-4 near the transport reference position X), avoiding the electrode portion (E4 near the transport reference position X).

[0024] Figure 3(b) shows plan views of each layer of the heater 300 (back surface layer 2, back surface layer 1, sliding surface layer 1, sliding surface layer 2). Multiple heating blocks, each consisting of a first conductor 301, a second conductor 303, and a heating element 302, are provided in the longitudinal direction of the heater 300 on the back surface layer 1 of the heater 300. In this embodiment, the heater 300 has a total of seven heating blocks HB1 to HB7 corresponding to heating regions in the longitudinal direction of the heater 300. Heating blocks HB1 to HB7 have heating elements 302a-1 to 302a-7 and heating elements 302b-1 to 302b-7, which are formed symmetrically in the short direction of the heater 300. The first conductor 301 is composed of a conductor 301a that connects to the heating elements (302a-1 to 302a-7) and a conductor 301b that connects to the heating elements (302b-1 to 302b-7). Similarly, the second conductor 303 is divided into seven conductors, 303-1 to 303-7, to correspond to the seven heating blocks HB1 to HB7.

[0025] In this embodiment, the heat-generating block HB4 is positioned at the transport reference position X, and the recording material P is used as the center. To accommodate A5 size paper width (148mm), the long-side width of heater 300 was made slightly wider at 150mm. Heating blocks HB3 and HB5 each have a long-side width of 17mm. This is to make the long-side width of the heating area of ​​heating blocks HB3 to HB5 slightly wider at 184mm so that it can accommodate B5 size paper width (182mm). Heating blocks HB2 and HB6 each have a long-side width of 14mm. This is to make the long-side width of the heating area of ​​heating blocks HB2 to HB6 slightly wider at 212mm so that it can accommodate A4 size paper width (210mm). Heating blocks HB1 and HB7 each have a long-side width of 4mm. This is to make the long-side width of heating blocks HB1 to HB7 wider at 220mm so that it can accommodate LTR size paper width (215.9mm). In the following description, the region with a width of 220 mm in the longitudinal direction of the heater 300, from heating block HB1 to HB7, will be referred to as the heating region L1 of the heater (see Figure 3(b)).

[0026] Electrodes E1-E7, E8-1, and E8-2 are connected to electrical contacts C1-C7, C8-1, and C8-2 to supply power from the control circuit 40 to the heater 300. Electrodes E1-E7 are electrodes for supplying power to the heating blocks HB1-HB7 via conductors 303-1-303-7, respectively. Electrodes E8-1 and E8-2 are common electrodes for supplying power to the seven heating blocks HB1-HB7 via conductors 301a and 301b, and are connected to common electrical contacts. In this embodiment, electrodes E8-1 and E8-2 are provided at both ends in the longitudinal direction of the heater 300, but for example, only electrode E8-1 may be provided on one side, or separate electrodes may be provided on the upstream and downstream sides in the transport direction of the recording material P.

[0027] Furthermore, the surface protective layer 307 of the back layer 2 of the heater 300 is formed except for the locations of electrodes E1~E7, E8-1, and E8-2, and the heater 300 is configured to allow connection of the power supply electrical contacts C1~C7, C8-1, and C8-2 (described later) to each electrode from the back layer side. In other words, the heater 300 is configured to be able to supply power from the back layer side. In addition, the heater 300 is configured to be able to independently control the power supplied to at least one of the multiple heat-generating blocks and the power supplied to the other heat-generating blocks. That is, the control circuit 40 detects the temperature of each of the heat-generating blocks HB1~HB7 and independently controls the temperature of the heat-generating elements 302a-1~302a-7 and 302b-1~302b-7.

[0028] The sliding surface layer 1 on the sliding surface side of the heater 300 is equipped with thermistors Th1 to Th7 as temperature sensing elements to detect the temperature of each heating block HB1 to HB7 of the heater 300. In this embodiment, thermistors Th1 to Th7 are constructed by forming a thin layer of material having NTC (Negative Temperature Coefficient) characteristics on a substrate. Note that this material may also have PTC (Positive Temperature Coefficient) characteristics. Since thermistors Th are provided for all heating blocks HB1 to HB7, the temperature of all heating blocks HB can be detected by detecting the resistance value of thermistor Th.

[0029] The sliding surface layer 1 has conductors ET1-1 to ET1-4 for detecting the resistance values ​​of the thermistors Th1 to Th4, and a common conductor EG1 for the thermistors Th1 to Th4, which serve as electrical contacts for energizing the four thermistors Th1 to Th4. The thermistor block TB1 is formed by the thermistors Th1 to Th4, conductors ET1-1 to ET1-4, and common conductor EG1.

[0030] Similarly, the sliding surface layer 1 has conductors ET2-5 to ET2-7 for detecting the resistance values ​​of the three thermistors Th5 to Th7, and a common conductor EG2 for thermistors Th5 to Th7, in order to energize the three thermistors Th5 to Th7. The thermistor block TB2 is formed by the thermistors Th5 to Th7, conductors ET2-5 to ET2-7, and the common conductor EG2. It will be done.

[0031] A sliding surface layer 2 on the sliding surface side of the heater 300 is provided with a sliding surface protection layer 308 (glass in this embodiment). However, the surface protection layer 308 is provided so as not to cover the conductors ET1-1 to ET1-4, ET2-5 to ET2-7, and common conductors EG1 and EG2, which serve as electrical contacts provided at both ends in the longitudinal direction of the heater 300. This is because FPCs (Flexible Printed Circuits) are to be joined to the conductors ET1-1 to ET1-4, ET2-5 to ET2-7, and common conductors EG1 and EG2 at the longitudinal ends of the heater 300. In this embodiment, FPCs 601 and 602 are provided as wires to electrically connect the thermistor Th of the heater 300 and the control circuit 40. FPC601 and FPC602 have conductive patterns similar to those of the conductors ET1-1 to ET1-4, ET2-5 to ET2-7, and the common conductor EG1, which are connected to the thermistor Th. FPC601 is joined to the conductors ET1-1 to ET1-4 and the common conductor EG1, and FPC602 is joined to the conductors ET2-5 to ET2-7 and the common conductor RG2, so that FPC601 and FPC602 function as electric wires.

[0032] As in this embodiment, when the heating region where the heating element is provided is divided into multiple locations, the number of temperature sensing elements increases, and so does the number of electrical contacts at the heater end. Since there are limitations on the area of ​​the heater end where the electrical contacts are provided, increasing the number of electrical contacts at the heater end as described above necessitates miniaturizing the electrical contacts. Consequently, the wires connecting to the electrical contacts at the heater end also need to be miniaturized. Therefore, it is preferable to use flexible sheets such as FPC or FFC (Flexible Flat Cable) as the wires connecting to the electrical contacts, as these allow for easy miniaturization of the connection points and conduction paths.

[0033] FPC601 and FPC602 are terminal connectors and conductor pattern protection members. Here, at the longitudinal end of the heater 300, conductors ET1-1 to ET1-4 and the common conductor EG1 are arranged at equal intervals in the short direction of the heater 300. Similarly, at the longitudinal end of the heater 300, conductors ET2-5 to ET2-7 and the common conductor EG2 are arranged at equal intervals in the short direction of the heater 300. Conductors ET1-1 to ET1-4 and the common conductor EG1 are arranged to overlap with the wire connection portion in FPC601, and conductors ET2-5 to ET2-7 and the common conductor EG2 are arranged to overlap with the wire connection portion in FPC602.

[0034] In this embodiment, FPC601 and FPC602 have a structure in which a copper foil pattern, which serves as a conductor, is sandwiched between polyimide films with an adhesive layer in between, and the copper foil pattern is exposed at the conductor connection portion. The exposed conductor portions of FPC601 and FPC602 are joined to the conductors (ET1-1 to ET1-4, ET2-5 to ET2-7) and common conductors (EG1, EG2) of the heater 300 using solder as a bonding agent, thereby connecting the FPC to each conductor.

[0035] (Joining configuration of heater 300 and heater support member 240) Next, the joining configuration of the heater 300 and the heater support member 240 will be explained with reference to Figures 4(a) to 4(d). Figure 4(a) shows the heater support member 240 with the heater 300 removed, and shows the portion of the heater support member 240 facing the back layer 2 of the heater 300. Figure 4(b) shows the heater 300 and FPC 601 and FPC 602 attached to the heater support member 240. Figure 4(c) is a cross-sectional view of the vicinity of the heater 300 at position Z in the longitudinal direction of the heater in Figure 4(a). Figure 4(d) is a cross-sectional view of the center position Y in the short direction of the heater 300, near the longitudinal end of the heater 300 on the FPC 601 side.

[0036] Electrical contacts C1-C7, C8-1, and C8-2 are connected to electrodes E1-E7, E8-1, and E8-2 of the heater 300. As shown in Figure 4(a), the heater support member 240 is an electrical contact. The area where C1-C7, C8-1, and C8-2 are positioned is open. This configuration allows the electrodes E1-E7, E8-1, and E8-2 to be electrically connected to the electrical contacts C1-C7, C8-1, and C8-2. In Figure 4(a), the areas of the heater support member 240 other than the opening are filled in or hatched to make the opening easier to see.

[0037] In this embodiment, the heater 300 is bonded to the heater support member 240 using adhesive 500. This is because if the heater position fluctuates during image formation, problems such as poor fixing of the toner image will occur. In this embodiment, where the heating element is divided and the temperature can be controlled for each divided area, the transport area of ​​the recording material P in the longitudinal direction of the heater 300 is determined from the size information of the recording material P, and a heat distribution corresponding to the transport area is formed. Therefore, if the position of the heater 300 fluctuates in the longitudinal direction of the heater 300, areas with insufficient heat generation will enter the transport area of ​​the recording material P, making it impossible to heat the toner image on the recording material P and thus preventing the toner image from being fixed on the recording material P. To prevent such a situation, the heater 300 is bonded to the heater support member 240. In Figure 4(a), 12 positions on the heater support member 240 where the adhesive 500 is placed are shown with hatching as bonding positions G1 to G12.

[0038] In this embodiment, the bonding positions G1 to G12 of the heater support member 240, where the adhesive 500 is applied, are aligned along the longitudinal direction of the heater 300. Adhesives 500-1 to 500-12 are placed correspondingly at each of the bonding positions G1 to G12, and the heater 300 is bonded to the heater support member 240. The adhesive 500 in this embodiment is a heat-resistant adhesive made of silicone rubber. Approximately 13 mg of adhesive is applied to each bonding position G1 to G12.

[0039] Figure 4(a) shows, with hatching, the area of ​​the heater support member 240 that the contact area S2 of the heater 300 contacts when the heater 300 is installed on the heater support member 240. As shown in Figure 2(b), the contact area S2 of the heater 300 is located at both ends in the short direction of the heater 300 and extends over almost the entire length of the heater 300 as shown in Figure 4(a). The contact area S2 is the minimum area that the heater support member 240 can adequately support the heater 300 when the heater 300 is subjected to pressure from the pressure roller 220 with the fixing film 210 or the like in between.

[0040] On the side of the heater 300 opposite to the contact surface S1 with the fixing film 210, all areas except the contact area S2 are non-contact areas S3. Nothing other than the adhesive 500 and electrodes comes into contact with the heater 300, and the heater is formed to be non-contact with the heater support member 240. This is to reduce the contact area between the heater 300 and the heater support member 240, thereby reducing heat transfer from the heating area L1 to the heater support member 240 and efficiently transferring the heater's heat to the fixing film 210. The non-contact area S3 is located between the contact areas 2 at both ends in the short direction of the heater 300 and extends over the entire length of the heater 300. In this embodiment, the non-contact area S3 extends to the ends of the heater 300 in the length direction, but it is sufficient if it extends at least to the area where the heating element 302 is located.

[0041] Furthermore, Figure 4(a) shows the non-contact surface H3 of the heater support member 240, which is the area of ​​the non-contact region S3 excluding the opening for the electrical contact C and the adhesive placement positions G1 to G12. To avoid contact with the heater 300, the non-contact surface H3 is recessed and one step lower in height than the area of ​​the heater support member 240 that the heater contact region S2 contacts.

[0042] As shown in Figure 4(c), counterbores are provided at bonding positions G1 to G12 of the heater support member 240 to prevent the adhesive 500 from flowing and overflowing into unintended areas. That is, the positions where the adhesive 500 of the heater support member 240 is applied are at a height relative to the non-contact surface H3. It is lowered by one level and recessed in the opposite direction from the heater 300.

[0043] Next, the bonding agent 400, which is the joint between the heater 300 and the FPC 601 shown in Figure 4(d), will be described. In this embodiment, the bonding agent 400 is solder that joins the exposed wire portion of the FPC 601 to the conductor ET1-2 of the heater 300. Note that the bonding agent 400 is not limited to solder; any conductive material that interposes between the heater 300 and the FPC 601 to join them is acceptable. Also, in Figure 4(d), the heating element end HE1, which is the end position on the FPC 601 side of the heating region L1 (first region) of the heater 300 in the longitudinal direction of the heater 300, is shown by a dotted line. The heating element end HE1 is the end of heating elements 302a-1 and 302b-1 in the longitudinal direction of the heater 300. The heater 300 has, in addition to the heat-generating region L1 described above, a bonding region L2 (second region) in contact with the bonding agent 400 and an intermediate region L3 (third region) between the heat-generating region L1 and the bonding region L2 in the longitudinal direction of the heater 300. That is, the intermediate region L3 is the region between the heat-generating element 302 and the bonding agent 400 in the longitudinal direction of the heater 300.

[0044] As shown in Figure 4(d), in the longitudinal direction of the heater 300, the adhesive 500-2 provided at bonding position G2 is located within the intermediate region L3. On the other hand, in the longitudinal direction of the heater 300, the adhesive 500-1 provided at bonding position G1 is provided so as to span the bonding region L2 and the intermediate region L3.

[0045] A feature of this embodiment of the present invention is that adhesives 500-1 and 500-2 are placed in the bonding region L2 and intermediate region L3 of the heater 300. It is sufficient that adhesive is provided in at least one of the bonding region L2 and intermediate region L3. With this arrangement of adhesives 500, when power is supplied to the heating element 302 to generate heat, the heat transmitted from the heating element end HE1 through the substrate 305 of the heater 300 can be transferred to the heater support member 240 via adhesives 500-1 and 500-2. Consequently, the heat transmitted to the bonding agent 400 can be reduced. The cross-section near the longitudinal end on the FPC 602 side has a structure symmetrical to that in Figure 4(d). That is, in this embodiment, in the longitudinal direction of the heater 300, the bonding agent 400 is provided on both sides of the heating region L1, and the bonding region L2 and intermediate region L3 are located on both sides of the heating region L1.

[0046] As described above, according to the configuration of this embodiment, when the heater 300 generates heat, the heat transferred from the end of the heating element 302 to the adhesive in the longitudinal direction of the heater 300 is dispersed to the adhesive 500, thereby reducing the rate at which the adhesive heats up. Consequently, the accumulation of thermal fatigue in the adhesive is mitigated, and cracks and peeling of the flexible sheet can be prevented.

[0047] (Effects of this embodiment) Next, the effect of this embodiment on reducing the heating rate of the joint will be explained in comparison with the comparative example. The comparative example is configured in a way that the adhesives 500-1, 500-2, 500-11, and 500-12 provided at the longitudinal ends of the heater 300 are absent compared to this embodiment.

[0048] The inventors conducted verification tests on this embodiment and comparative example to confirm the effect of reducing the heating rate. In the verification test, with the fixing device 200 at room temperature of 23°C, thermistors Th1 to Th7 were raised to 230°C in approximately 7.0 seconds, and Th1 to Th7 were temperature-controlled at 230°C. Figure 5 shows the temperature changes of Th1 and the bonding agent at this time. In both the comparative example and this embodiment, the heater 300 has a symmetrical structure in the longitudinal direction, and the positional relationship between the bonding agent and its surrounding members is the same, so the temperature changes of the bonding agent are approximately the same.

[0049] As shown in Figure 5, the comparative example shows a steeper rise in the temperature of the bonding agent, while the embodiment shows a more gradual rise in temperature of the bonding agent. Specifically, in the comparative example, the temperature of the bonding agent reached 130°C. While it normally takes 7.0 seconds to reach the specified temperature, in this embodiment it reaches 130°C in 10.0 seconds, indicating a reduced heating rate. This is thought to be due to the effect of heat transfer to the heat-conducting members, adhesives 500-1 and 500-2, which disperse the heat before it reaches the bonding agent 400. To fully obtain the effect of reducing the heating rate, it is desirable that the contact thermal resistance of the heat-conducting members in contact with the heater is low. Therefore, adhesives with high adhesion at the contact point with the heater, as in this embodiment, are particularly effective.

[0050] As described above, with the configuration of this embodiment, the adhesive functions as a heat conductive member, dispersing the heat transferred to the bonding agent, thereby reducing the rate at which the bonding agent connecting the FPC and the heater's electrical contacts heats up. Consequently, the accumulation of thermal fatigue in the bonding agent can be suppressed, thus preventing problems such as cracks in the joint and delamination of the flexible sheet. In the configuration of this embodiment, no solder cracks or FPC delamination occurred throughout the product's lifespan.

[0051] Although preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its gist. For example, in this embodiment, multiple heat conductive members (adhesive 500) are provided between the heating element end HE1 and the bonding agent 400 in order to sufficiently obtain the effect of reducing the heating rate, but even if only one heat conductive member is provided, the effect of reducing the heating rate can be obtained. In such a configuration, the heat conductive member may be provided only in the bonding region L2, or only in the intermediate region L3, but the effect of reducing the heating rate of the bonding agent 400 is more pronounced when it is provided in the intermediate region L3.

[0052] Furthermore, in this embodiment, an adhesive is used as a heat conductive member that contacts the heater 300 from the heating element ends HE1, HE2 to the bonding agent, but the configuration to obtain a similar effect is not limited to this. For example, instead of the adhesives 500-1, 500-2, 500-11, and 500-12 at the two outer ends of the heating element, a heat conductive grease may be provided on the heater as a heat conductive member. Alternatively, instead of the adhesives 500-1, 500-2, 500-11, and 500-12 at the two outer ends of the heating element, the heater support member 240 may be brought into contact with the heater 300, and a part of the heater support member 240 may be configured to function as a heat conductive member.

[0053] This embodiment includes the following configuration (and method). (Composition 1) A cylindrical film and A heater having a heating element, which is elongated in the direction of the generatrix of the film and is arranged in the internal space of the film along the direction of the generatrix of the film, A support member is arranged in the internal space of the film and supports the heater, A roller that is in contact with the outer surface of the film and forms a nip portion that sandwiches the recording material between itself and the film, The heater is joined to the electric wire with an adhesive, and the electric wire is electrically connected to the heater, An image heating device comprising the nip portion, which heats the image formed on the recording material while transporting the recording material, A heat conductive member is further provided between the heater and the support member, which contacts the heater and the support member. The heater has, in the direction of the busbar, a first region on which the heating element is provided, a second region on which the bonding agent is provided, and a third region between the first region and the second region. The surface of the heater facing the seating surface of the support member, the surface of the third region has a region that does not come into contact with the support member. The image heating device is characterized in that the heat conductive member is in contact with the heater and the support member in at least one of the second and third regions of the heater. (Configuration 2) The image heating device according to configuration 1, characterized in that the heat conductive member is in contact with the heater and the support member in at least the third region. (Composition 3) The image heating device according to configuration 1 or 2, characterized by comprising a plurality of the aforementioned heat conductive members. (Composition 4) The image heating device according to any one of configurations 1 to 3, characterized in that the heater comprises a substrate on which the heating element is formed, a temperature sensing element formed on the substrate, and an electrical contact formed on the substrate and electrically connected to the temperature sensing element, and the electric wire is joined to the electrical contact by the bonding agent. (Composition 5) The image heating device according to configuration 4, characterized in that the electric wire is an FPC or FFC provided so as to overlap the electrical contact. (Composition 6) The image heating device further comprises a control unit that controls the temperature of the heating element, The image heating device according to any one of configurations 1 to 5, characterized in that the electric wire electrically connects the heater and the control unit. (Composition 7) The image heating apparatus according to any one of the configurations 1 to 6, characterized in that the bonding agent is solder. (Composition 8) The image heating device according to any one of configurations 1 to 7, characterized in that the heat conductive member is an adhesive that bonds the heater and the support member. (Composition 9) The image heating device according to any one of configurations 1 to 7, characterized in that the heat conducting member is part of the support member. (Composition 10) The image heating device according to any one of configurations 1 to 7, characterized in that the heat conductive member is a heat conductive grease. (Composition 11) An image forming unit that forms an image on the recording material, A fixing unit that fixes the image formed on the recording material to the recording material, In an image forming apparatus having, An image forming apparatus characterized in that the fixing unit is an image heating device according to any one of the configurations 1 to 10. [Explanation of symbols]

[0054] 200... Fixing device (image heating device), 210... Fixing film, 220... Pressure roller, 240... Heater support member (support member), 300... Heater, 400... Bonding agent, 500... Adhesive (heat conductive member), 601... FPC (electric wire), L1... Heating area (first area), L2... Bonding area (second area), L3... Intermediate area (third area)

Claims

1. A cylindrical film and A heater having a heating element, which is elongated in the direction of the generatrix of the film and is arranged in the internal space of the film along the direction of the generatrix of the film, A support member is arranged in the internal space of the film and supports the heater, A roller that is in contact with the outer surface of the film and forms a nip portion that sandwiches the recording material between itself and the film, The FPC is joined to the heater by solder and is electrically connected to the heater, An image heating device comprising the nip portion, which heats the image formed on the recording material while transporting the recording material, The heater is bonded to the support member with an adhesive. The heater has, in the direction of the busbar, a first region where the heating element is provided, a second region where the solder is provided, and a third region between the first and second regions where neither the heating element nor the solder is provided. In the transport direction of the recording material perpendicular to the aforementioned generatrix direction, the surface of the third region facing the seating surface of the support member has a non-contact region that does not come into contact with the support member. The image heating device is characterized in that the adhesive is provided in the non-contact area and in contact with the heater and the support member, and is provided in at least one of the second and third areas of the heater in the direction of the generatrix.

2. The image heating apparatus according to claim 1, characterized in that the adhesive is in contact with the heater and the support member in at least the third region.

3. The image heating device according to claim 1, characterized in that the adhesive is provided in multiple regions.

4. The heater comprises a substrate on which the heating element is formed, a temperature sensing element formed on the substrate, and an electrical contact formed on the substrate and electrically connected to the temperature sensing element, and the FPC is characterized in that the electrical contact and the solder are joined together. The image heating device described in item 1.

5. The image heating device according to claim 4, characterized in that the FPC is provided so as to overlap the electrical contacts.

6. The image heating device further comprises a control unit that controls the temperature of the heating element, The image heating apparatus according to claim 1, characterized in that the FPC electrically connects the heater and the control unit.

7. The image heating apparatus according to claim 1, characterized in that the adhesive is a heat conductive member that comes into contact with the heater and the support member.

8. An image forming unit that forms an image on the recording material, A fixing unit that fixes the image formed on the recording material to the recording material, In an image forming apparatus having, An image forming apparatus characterized in that the fixing unit is an image heating device according to any one of claims 1 to 7.

Images