Heating device, fixing device, image forming device

Abstract

The goal is to create a configuration that prevents scattered toner from entering the connector, while keeping the space to a minimum. [Solution] The resistor block 60 includes a plurality of resistors 6 arranged in the main direction on the surface of the base member 600. The plurality of input electrodes 61 are conductive members electrically connected to the resistor block 60 and positioned on the surface of the base member end 600a, which is the end of the base member 600 in the main direction. The connector 72 has a clamping portion 723 including a pair of arm portions 722 that clamp the base member end 600a and a plurality of conductive output electrodes 73 positioned on the inner surfaces of the pair of arm portions 722 that contact the plurality of input electrodes 61. The sheet member 6x is bonded to the end face of the base member end 600a and the side surface of the clamping portion 723, and closes the gap between the end face of the base member end 600a and the side surface of the clamping portion 723.

Description

Technical Field

[0001] The present invention relates to a heating device, a fixing device, and an image forming device having a plurality of resistors arranged on the surface of a base member.

Background Art

[0002] An electrophotographic image forming apparatus includes a fixing device that heats and presses a toner image transferred onto a sheet. The fixing device includes a heating device, a fixing member heated by the heating device, and a pressure member that rotates while urging the sheet on which the toner image is formed toward the fixing member.

[0003] In the fixing device, the heating device may have a base member and one or more planar resistance blocks disposed on the surface of the base member. The resistance block includes a plurality of resistors arranged in a main direction. The main direction is a direction intersecting the conveyance direction of the sheet.

[0004] The resistance block is supplied with power through a plurality of input electrodes disposed on the surface of the end portion of the base member in the main direction.

[0005] For example, it is known that a connector has a plurality of output electrodes supplied with power from a power source, and the connector is attached to an end portion of the base member (see, for example, Patent Document 1). By attaching the connector to the end portion of the base member, the plurality of output electrodes come into contact with the plurality of input electrodes.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Incidentally, in the image forming apparatus, there is a risk that scattered toner may enter the connector through the gap between the end of the base member and the connector. The entry of scattered toner into the connector may cause undesirable situations such as poor contact of the electrodes.

[0008] On the other hand, in the region at the end of the fixing device in the main direction, various components such as the gear mechanism that drives the rotating body of the fixing device are arranged at a high density, leaving little free space.

[0009] The object of the present invention is to provide a heating device, a fixing device, and an image forming device that can implement a configuration to prevent scattered toner from entering the connector in the smallest possible space. [Means for solving the problem]

[0010] A heating device according to one aspect of the present invention comprises a base member, one or more resistance blocks, a plurality of input electrodes, a connector, and a sheet member. The resistance block includes a plurality of resistors arranged in the main direction on the surface of the base member. The plurality of input electrodes are conductive members electrically connected to the resistance block and disposed on the surface of the base member end, which is the end of the base member in the main direction. The connector has a clamping portion including a pair of arm portions that clamp the base member end, and a plurality of conductive output electrodes disposed on the inner surfaces of the pair of arm portions and in contact with the plurality of input electrodes. The sheet member is bonded to the end face of the base member end and the side surface of the clamping portion, and closes the gap between the end face of the base member end and the side surface of the clamping portion.

[0011] A fixing device according to another aspect of the present invention comprises a heating device, a cylindrical fixing member heated by the heating device, and a pressurizing member that rotates the paper on which the toner image is formed while biasing it toward the fixing member.

[0012] An image forming apparatus according to another aspect of the present invention comprises an image forming unit, a transfer device, and a fixing device. The image forming unit forms a toner image on the surface of an image carrier. The transfer device transfers the toner image from the image carrier to paper. The fixing device heats and pressurizes the toner image on the paper. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a heating device, a fixing device, and an image forming device that can implement a configuration to prevent scattered toner from entering the connector in the smallest possible space. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a diagram showing the configuration of an image forming apparatus equipped with a heating device according to the first embodiment. [Figure 2] Figure 2 is a diagram showing the configuration of a fixing device equipped with a heating device according to the first embodiment. [Figure 3] Figure 3 is a plan view of the heating surface in the heating device according to the first embodiment. [Figure 4] Figure 4 is a block diagram showing the configuration of the control device in an image forming apparatus. [Figure 5] Figure 5 is an exploded perspective view of the base member end and connector in the heating device according to the first embodiment, as seen from the lower side. [Figure 6] Figure 6 is an exploded perspective view of the base member end and connector in the heating device according to the first embodiment, as seen from the upper side. [Figure 7] Figure 7 is a side view of the base member end and connector before the sheet member is attached in the heating device according to the first embodiment. [Figure 8] Figure 8 is a side view of the base member end and connector in the heating device according to the first embodiment. [Figure 9] Figure 9 is a side view of the base member end and connector in the heating device according to the second embodiment. [Figure 10]FIG. 10 is a side view of a base member end portion and a connector in the heating device according to the third embodiment.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are an example of embodying the present invention and do not limit the technical scope of the present invention.

[0016] [First Embodiment] The heating device 53 according to the first embodiment is included in the fixing device 5 of the image forming apparatus 10 (see FIG. 1).

[0017] [Configuration of Image Forming Apparatus 10] The image forming apparatus 10 includes a printing device 4 that performs a printing process for forming an image on a sheet of paper 9.

[0018] The printing device 4 performs the printing process by an electrophotographic method. The sheet of paper 9 is an example of a sheet-like image forming medium.

[0019] As shown in FIG. 1, the image forming apparatus 10 includes a sheet conveying device 3, a printing device 4, and a control device 8 provided in the main body 1.

[0020] The printing device 4 includes one or more image forming units 4x, an optical scanning device 40, a transfer device 44, and a fixing device 5. The image forming unit 4x includes a drum-shaped photoreceptor 41, a charging device 42, a developing device 43, a drum cleaning device 45, and the like.

[0021] The sheet conveying device 3 includes a sheet feeding device 30 and a plurality of sets of conveying roller pairs 31. The sheet feeding device 30 feeds the sheet of paper 9 accommodated in the sheet accommodating portion 2 to the conveyance path 300 in the main body 1. The conveyance path 300 forms a passage through which the sheet of paper 9 is conveyed.

[0022] Multiple sets of transport rollers 31 rotate with the driving force of a motor (not shown) to transport the paper 9 along the transport path 300, and then discharge the paper 9 into the discharge tray 101.

[0023] The paper 9 passes through the transfer position P1 and fixing position P2 in the transport path 300 and is discharged to the discharge tray 101.

[0024] In the following description, the direction in which the paper 9 is transported along the transport path 300 is referred to as the transport direction D01. The fixing position P2 is located downstream of the transfer position P1 in the transport direction D01.

[0025] Furthermore, the direction intersecting the transport direction D01 in the transport path 300 is referred to as the main direction D1. In this embodiment, the main direction D1 is the direction perpendicular to the transport direction D01.

[0026] The printing device 4 forms a toner image on the paper 9 that is transported along the transport path 300. The toner is an example of a granular developer.

[0027] The image forming apparatus 10 shown in Figure 1 is a tandem-type color image forming apparatus. Therefore, the printing apparatus 4 is equipped with four image forming units 4x corresponding to the four toners: yellow, cyan, magenta, and black.

[0028] In each of the image forming units 4x, the photoreceptor 41 rotates, and the charging device 42 charges the surface of the photoreceptor 41. Furthermore, the optical scanning device 40 writes an electrostatic latent image onto the surface of the photoreceptor 41 by scanning with laser light.

[0029] Furthermore, the developing device 43 develops the electrostatic latent image as a toner image by supplying the toner to the surface of the photoreceptor 41.

[0030] The photoreceptor 41 is an example of an image carrier that carries and rotates the toner image. Each image forming unit 4x is an example of an image forming unit that forms the toner image on the surface of the photoreceptor 41.

[0031] The transfer device 44 transfers the toner image from the photoreceptor 41 to the paper 9. The transfer device 44 comprises an intermediate transfer belt 441, four primary transfer devices 442 corresponding to the four image forming units 4x, a secondary transfer device 443, and a belt cleaning device 444.

[0032] The primary transfer device 442 transfers the toner image on the surface of the photoreceptor 41 to the surface of the intermediate transfer belt 441. The secondary transfer device 443 transfers the toner image on the intermediate transfer belt 441 to the paper 9 at the transfer position P1 of the transport path 300.

[0033] If the image forming apparatus 10 is a monochrome image forming apparatus, the secondary transfer apparatus 443 transfers the toner image on the photoreceptor 41 to the paper 9 at the transfer position P1.

[0034] The drum cleaning device 45 removes waste toner remaining on the surface of the photoreceptor 41. The belt cleaning device 444 removes the waste toner remaining on the intermediate transfer belt 441.

[0035] The fuser unit 5 includes a pressure roller 50 and a heating device 53 (see Figures 1 and 2). The fuser unit 5 heats and pressurizes the toner image on the paper 9 while transporting the paper 9 at the fixing position P2 of the transport path 300. In this way, the fuser unit 5 fixes the toner image to the paper 9.

[0036] [Control device 8] The control device 8 performs various data processing and controls equipment such as the sheet transport device 3 and the printing device 4. The control target of the control device 8 includes the fixing device 5.

[0037] As shown in Figure 4, the control device 8 includes a CPU (Central Processing Unit) 81 and peripheral devices. These peripheral devices include RAM (Random Access Memory) 82, a secondary storage device 83, and a signal interface 84.

[0038] Furthermore, the control device 8 includes a communication device 85 and a power supply circuit 86.

[0039] The CPU81 is a processor that performs various data processing and control tasks by executing computer programs.

[0040] RAM82 is a computer-readable volatile memory device. RAM82 primarily stores the computer program executed by CPU81 and the data that CPU81 outputs and references during the process of performing various operations.

[0041] The CPU 81 includes a plurality of processing modules that are realized by executing the computer program. The plurality of processing modules include a main control unit 8a, a heater control unit 8b, and a print control unit 8c, among others.

[0042] The main control unit 8a performs start control and other operations to initiate various processes in response to operations performed on an operating device (not shown).

[0043] The heater control unit 8b controls the amount of power supplied to the heating device 53 by controlling the fixing temperature. The heater control unit 8b adjusts the amount of power supplied to the heating device 53 by controlling the power supply circuit 86.

[0044] The power supply circuit 86 supplies power to the heating device 53 in accordance with the power supply command from the heater control unit 8b.

[0045] The print control unit 8c controls the sheet transport device 3. Furthermore, the print control unit 8c causes the print device 4 to execute the print process in synchronization with the transport of paper 9 by the sheet transport device 3.

[0046] The secondary storage device 83 is a computer-readable, non-volatile storage device. For example, flash memory, a hard disk drive, or both may be used as the secondary storage device 83.

[0047] The signal interface 84 converts signals output by various sensors, such as the temperature sensor 55, into digital data and transmits that digital data to the CPU 81. Furthermore, the signal interface 84 converts control commands output by the CPU 81 into control signals and transmits those control signals to the controlled device.

[0048] The communication device 85 performs communication with other devices, such as a host device that sends print jobs to the image forming apparatus 10. The CPU 81 communicates with the other devices through the communication device 85.

[0049] In the following explanation, the direction intersecting the main direction D1 will be referred to as the secondary direction D2. The secondary direction D2 is the direction along the conveying direction D01.

[0050] [Fusing device 5] As shown in Figure 2, the fixing device 5 comprises a pressure roller 50, a fixing member 51, a guide member 52, a heating device 53, a biasing mechanism 54, and a temperature sensor 55. The pressure roller 50, fixing member 51, guide member 52, and heating device 53 are each arranged along the main direction D1 at the fixing position P2.

[0051] The fixing member 51 is a flexible cylindrical member. In other words, the fixing member 51 is an endless belt-shaped flexible cylinder. For example, the fixing member 51 is a cylindrical film member.

[0052] The pressure roller 50 rotates with the driving force of a motor (not shown). The pressure roller 50 forms a nip Np1 between itself and the fixing member 51. The nip Np1 is formed at the fixing position P2.

[0053] The pressure roller 50 biases the paper 9 passing through the fixing position P2 towards the fixing member 51. The pressure roller 50 is an example of a pressure member that rotates while biasing the paper 9 on which the toner image has been formed toward the fixing member 51.

[0054] The fixing member 51 rotates in accordance with the rotation of the pressure roller 50. The guide member 52 guides the inner surfaces of both ends of the fixing member 51 in the main direction D1 along the annular path.

[0055] The heating device 53 is positioned inside the annular fixing member 51 and heats the fixing member 51. The heating device 53 comprises a base member 600 and one or more resistance blocks 60 (see Figures 2 and 3).

[0056] The main direction D1 is the longitudinal direction of the fixing member 51, the base member 600, and the pressure roller 50. The secondary direction D2 is the short-range direction of the fixing member 51, the base member 600, and the pressure roller 50.

[0057] The base member 600 is arranged along the main direction D1. For example, the base member 600 is a molded member made of synthetic resin. The biasing mechanism 54 biases the base member 600 toward the transfer position P1. As a result, the heating surface of the base member 600, which is the surface facing the transfer position P1, comes into contact with the inner surface of the fixing member 51.

[0058] The biasing mechanism 54 elastically biases the base member 600 with an elastic member such as a spring. One or more resistance blocks 60 are arranged on the heated surface of the base member 600 (see Figure 3).

[0059] In the example shown in Figure 3, the heating device 53 has a plurality of resistance blocks 60 arranged in the main direction D1. Each resistance block 60 includes a plurality of resistors 6 arranged in the main direction D1 on the heating surface of the base member 600.

[0060] Each of the resistors 6 is a heat-generating element that generates heat when a voltage is applied to it. Multiple resistors 6 are arranged with a first spacing in the main direction D1. Multiple resistor blocks 60 are arranged with a second spacing in the main direction D1.

[0061] As the fixing member 51 rotates, its inner surface slides against the heating surface of the base member 600. The fixing member 51 is heated by the multiple heat-generating resistance blocks 60.

[0062] The heating surface of the heating device 53 is a planar heater having multiple resistors 6 (see Figure 4). A lubricant is applied to the inner surface of the fixing member 51.

[0063] In addition to the multiple resistance blocks 60, multiple input electrodes 61 and multiple transmission patterns 62 are also arranged on the heating surface of the base member 600. Each of the multiple input electrodes 61 and the multiple transmission patterns 62 is a conductive material such as copper foil or copper plate.

[0064] Multiple input electrodes 61 are arranged on the surface of the base member end 600a, which is the end of the base member 600 in the main direction D1. Multiple input electrodes 61 are electrically connected to multiple resistors 6 by multiple transmission patterns 62.

[0065] The multiple input electrodes 61 include multiple anodes 61a and at least one cathode 61b to which the voltage supplied to the multiple resistor blocks 60 is applied.

[0066] The temperature sensor 55 detects the temperature of the heating device 53. For example, the temperature sensor 55 is a thermistor. In this embodiment, the temperature sensor 55 measures the temperature of the heating surface at the end portion 600a of the base member.

[0067] The temperature detected by the temperature sensor 55 is used for fixing temperature control. This fixing temperature control is a feedback control that controls the power supplied to multiple resistor blocks 60 by comparing the temperature detected by the temperature sensor 55 with a preset target temperature.

[0068] The heating device 53 further includes a wire harness 7 that transmits power supplied from the power supply circuit 86 to a plurality of input electrodes 61 (see Figures 5-8). The wire harness 7 has a plurality of cables 71 connected to the power supply circuit 86 and connectors 72 connected to the ends of the plurality of cables 71.

[0069] The connector 72 has multiple output electrodes 73 that receive power from the power supply circuit 86 through multiple cables 71 (see Figure 6). Each output electrode 73 is a conductive material such as a copper plate. When the connector 72 is attached to the end portion 600a of the base member, the multiple output electrodes 73 come into contact with the multiple input electrodes 61.

[0070] The output power of the power supply circuit 86 is supplied to multiple resistor blocks 60 through multiple cables 71, multiple output electrodes 73, and multiple input electrodes 61.

[0071] Incidentally, in the image forming apparatus 10, there is a risk that scattered toner may enter the connector 72 through the gap between the base member end 600a and the connector 72. The entry of scattered toner into the connector 72 may cause undesirable situations such as poor contact of the electrodes.

[0072] On the other hand, in the region at the end of the main direction D1 in the fixing device 5, various devices such as the gear mechanism that drives the rotating body of the fixing device 5 are arranged at a high density, leaving little free space. For example, the rotating body is a pressure roller 50.

[0073] The heating device 53 is configured to prevent the scattered toner from entering the connector 72. Its configuration will be described below.

[0074] The connector 72 has a clamping portion 723 and an engaging portion 724 (see Figures 5-8). The clamping portion 723 includes a housing portion 721 and a pair of arm portions 722. The pair of arm portions 722 are formed extending in parallel from the housing portion 721 and facing each other.

[0075] The housing portion 721 holds the ends of multiple cables 71. The base member end portion 600a is inserted between the pair of arm portions 722, so that the pair of arm portions 722 clamp the base member end portion 600a.

[0076] Multiple output electrodes 73 are arranged on the inner surfaces of a pair of arm portions 722. The state in which the pair of arm portions 722 clamp the end portion 600a of the base member is the state in which the connector 72 is attached to the end portion 600a of the base member.

[0077] When the connector 72 is attached to the end portion 600a of the base member, multiple output electrodes 73 come into contact with multiple input electrodes 61.

[0078] The base member 600 has a protrusion 603 formed on the surface opposite to the surface on which the multiple input electrodes 61 are arranged at the base member end 600a (see Figure 6). The protrusion 603 is formed extending in the secondary direction D2.

[0079] One of the pair of arm portions 722 has a recess 725 into which a protrusion 603 is inserted. The connector 72 is attached to the base member end portion 600a along the secondary direction D2. When the connector 72 is attached to the base member end portion 600a, the protrusion 603 is inserted into the recess 725 and guides the connector 72 along the secondary direction D2.

[0080] Furthermore, the protrusion 603, when inserted into the recess 725, restricts the movement of the connector 72 attached to the end portion 600a of the base member in the main direction D1.

[0081] The engaging portion 724 engages with the engaged portion 52a, which is part of the fixing device 5, to hold the connector 72 in a mounted state on the end portion 600a of the base member. The engaging portion 724 restricts the movement of the connector 72 in the secondary direction D2 by engaging with the engaged portion 52a.

[0082] The engaging portion 724 is elastically deformable. By elastically deforming, the engaging portion 724 switches between an engaged state in which it engages with the engaged portion 52a and a released state in which it is released from the engaged portion 52a.

[0083] In this embodiment, the engaged portion 52a is formed at the end of the guide member 52 in the main direction D1. The base member 600 and the guide member 52 are held in a fixed positional relationship by the holding member 56 (see Figures 7 and 8).

[0084] The heating device 53 further includes a sheet member 6x that seals the gap between the connector 72 and the base member end 600a (see Figures 5, 6, and 8).

[0085] The sheet member 6x is bonded to the end face of the base member end 600a and the side surface of the clamping portion 723, filling the gap between the end face of the base member end 600a and the side surface of the clamping portion 723 (see Figure 8). The surfaces to which the sheet member 6x is bonded are the end face of the base member end 600a in the main direction D1 and the outer side surface of the clamping portion 723 in the main direction D1.

[0086] Figures 5-7 show the state before the sheet member 6x is bonded, and Figure 8 shows the state after the sheet member 6x has been bonded.

[0087] For example, the sheet member 6x is an adhesive sheet with an adhesive formed on one surface. In this case, the sheet member 6x is adhered to the end face of the base member end 600a and the side surface of the clamping portion 723 by the adhesive.

[0088] In this embodiment, the base member end portion 600a includes a first plate-shaped portion 601 and a second plate-shaped portion 602 (see Figures 5-7). The first plate-shaped portion 601 is the portion on which a plurality of input electrodes 61 are arranged and is inserted between a pair of arm portions 722. The second plate-shaped portion 602 is connected to the first plate-shaped portion 601 and is the portion facing the tips of the pair of arm portions 722.

[0089] The sheet member 6x is bonded to the side surface of the clamping portion 723 in the connector 72, the end face of the first plate-like portion 601, and the end face of the second plate-like portion 602. As a result, the sheet member 6x is stably bonded to a relatively large surface.

[0090] In the heating device 53, the area occupied by the sheet member 6x is very small. By employing the heating device 53, a configuration that prevents the scattered toner from entering the connector 72 can be realized in a very small space.

[0091] [Second Embodiment] Next, with reference to Figure 9, the heating device 53A according to the second embodiment will be described.

[0092] The heating device 53A has a configuration in which a sheet member 6y is added to the heating device 53. The sheet member 6y is bonded to the lower surface of the connector 72 and the lower surface of the base member end portion 600a. In this embodiment, the lower surface of the base member end portion 600a is the lower surface of the second plate-like portion 602.

[0093] The sheet member 6y seals the gap between the lower surface of the connector 72 and the lower surface of the base member end 600a. The use of the heating device 53A more reliably prevents the scattered toner from entering the connector 72.

[0094] [Third Embodiment] Next, with reference to Figure 10, a heating device 53B according to the third embodiment will be described. Heating device 53B is a modified example of heating device 53A.

[0095] In the heating device 53A, the sheet member 6y is bonded to the lower surface of the connector 72 and to the lower surface and outer surface of the second plate-shaped portion 602 at the base member end 600a.

[0096] The sheet member 6y seals the gap between the lower surface of the connector 72 and the lower surface of the base member end 600a. When the heating device 53B is used, the same effect as when the heating device 53A is used is obtained. Furthermore, in the heating device 53B, the sheet member 6y is stably bonded to a relatively wide surface.

[0097] [Notes on the invention] The following is an overview of the invention extracted from the above-described embodiments. Note that each configuration and processing function described below can be selected and combined as desired.

[0098] <Note 1> Base member and One or more resistor blocks including a plurality of resistors arranged in the main direction on the surface of the base member, A plurality of conductive input electrodes are electrically connected to the resistor block and are arranged on the surface of the base member end, which is the end of the base member in the main direction, A connector having a clamping portion including a pair of arm portions that clamp the end of the base member, and a plurality of conductive output electrodes arranged on the inner surface of the pair of arm portions and in contact with the plurality of input electrodes, A heating device comprising a sheet member that is adhered to the end face of the base member end and the side surface of the clamping portion, and that seals the gap between the end face of the base member end and the side surface of the clamping portion.

[0099] <Note 2> The end portion of the base member is The plurality of input electrodes are arranged on a first plate-shaped portion which is inserted between the pair of arm portions, It has a second plate-shaped portion connected to the first plate-shaped portion and facing the tips of the pair of arm portions, The heating device according to Appendix 1, wherein the sheet member is bonded to the end face of the first plate-like portion and the end face of the second plate-like portion.

[0100] <Note 3> A heating device as described in Appendix 1 or Appendix 2 above, A cylindrical fixing member heated by the aforementioned heating device, A fixing device comprising: a pressing member that rotates the paper on which a toner image has been formed while biasing it toward the fixing member.

[0101] <Note 4> An image forming unit that forms a toner image on the surface of an image carrier, A transfer device for transferring the toner image from the image carrier to the paper, An image forming apparatus comprising: a fixing device according to Appendix 3 for heating and pressurizing the toner image on the aforementioned paper. [Explanation of Symbols]

[0102] 4: Printing device 4x: Image forming unit (image forming section) 5: Fixing device 6: Resistor 6x, 6y: Sheet material 7: Wire harness 8: Control device 10: Image forming apparatus 50: Pressure roller (pressure component) 51: Fixing member 52: Guide component 52a: Engaged part 53,53A,53B:Heating device 60: Resistor block 61: Input electrode 62: Transmission Pattern 71: Cable 72: Connector 73: Output electrode 600: Base member 600a: Base member end 601: First plate-like part 602: Second plate-like portion 721: Housing Department 722: Arm section 723: Sandwiching part 724: Engaging part

Claims

1. Base member and One or more resistor blocks including a plurality of resistors arranged in the main direction on the surface of the base member, A plurality of conductive input electrodes are electrically connected to the resistor block and are arranged on the surface of the base member end, which is the end of the base member in the main direction, A connector having a clamping portion including a pair of arm portions that clamp the end of the base member, and a plurality of conductive output electrodes arranged on the inner surface of the pair of arm portions and in contact with the plurality of input electrodes, A heating device comprising a sheet member that is adhered to the end face of the base member end and the side surface of the clamping portion, and that seals the gap between the end face of the base member end and the side surface of the clamping portion.

2. The end portion of the base member is The plurality of input electrodes are arranged on a first plate-shaped portion which is inserted between the pair of arm portions, It has a second plate-shaped portion connected to the first plate-shaped portion and facing the tips of the pair of arm portions, The heating device according to claim 1, wherein the sheet member is bonded to the end face of the first plate-like portion and the end face of the second plate-like portion.

3. A heating device according to claim 1 or claim 2, A cylindrical fixing member heated by the aforementioned heating device, A fixing device comprising: a pressing member that rotates the paper on which a toner image has been formed while biasing it toward the fixing member.

4. An image forming unit that forms a toner image on the surface of an image carrier, A transfer device for transferring the toner image from the image carrier to the paper, An image forming apparatus comprising a fixing device according to claim 3 for heating and pressurizing the toner image on the paper.

Images