BACKGROUND

[0001] An image forming apparatus may include a fixing device to heat and press a sheet on to which a toner image is transferred, to fix the toner image to the sheet. The fixing device may include a fixing belt to heat the sheet and a pressure roller to press the fixing belt. A nip portion through which the sheet passes may be formed between the fixing belt and the pressure roller. The toner image may be fixed to the sheet by heating and pressurization based on the sheet passing through the nip portion.

BRIEF DESCRIPTION OF DRAWINGS

[0002] Various examples will be described below by referring to the following figures.

[0003] FIG. 1 is a schematic view of an image forming apparatus according to an example.

[0004] FIG. 2 is a view schematically illustrating a cross section of a fixing device in the image forming apparatus of FIG. 1 according to an example.

[0005] FIG. 3 is a perspective view illustrating the fixing device of FIG. 2 according to an example.

[0006] FIG. 4 is a perspective view illustrating a state where a roller module is extracted from the fixing device of FIG. 3 according to an example.

[0007] FIG. 5 is a perspective view illustrating a state where a heater module is extracted from a belt module of the roller module of FIG. 4 according to an example.

[0008] FIG. 6 is a cross-sectional view of the roller module of FIG. 4 according to an example.

[0009] FIG. 7 is an enlarged cross-sectional view of a base frame, a base holder, and a heater holder of the roller module of FIG. 6 according to an example. [0010] FIG. 8 is a perspective view schematically illustrating an internal structure of a housing and the roller module of the fixing device of FIG. 3 according to an example.

[0011] FIG. 9 is a side view illustrating the roller module of FIG. 4 according to an example.

[0012] FIG. 10 is a side view illustrating the belt module of the roller module of FIG. 9 according to an example.

[0013] FIG. 11 is a side view illustrating the heater module of the roller module of FIG. 9 according to an example.

[0014] FIG. 12 is a cross-sectional view of a base frame, a base holder, and a heater holder of a roller module according to a modification example.

[0015] FIG. 13 is a view schematically illustrating a belt module of the roller module according to the modification example.

[0016] FIG. 14 is a view schematically illustrating a heater module of the roller module according to the modification example.

[0017] FIG. 15 is a perspective view illustrating the roller module of the modification example.

[0018] FIG. 16 is a perspective view illustrating a state where a fixing unit is removed from a support member of the roller module of FIG. 15 according to an example.

DETAILED DESCRIPTION

[0019] In various examples as described below, an image forming apparatus includes a housing of a fixing device and a roller module. In an example, the housing is replaceable and includes a fixing unit extending in an axial direction and a support member to rotatably support the fixing unit. The support member is to contact a rail of the housing such that the roller module may slide along the axial direction between a roller insertion position, where the roller module may be located in an accommodation space, and a roller extraction position, where the roller module may be extracted from the housing. The "roller insertion position, where the roller module may be located in the accommodation space" indicates a state where at least a part of the roller module is located in the accommodation space, a state where the entirety of the roller module is located in the accommodation space, a state where a part of the roller module is located in the accommodation space, or a state where portions of the roller module excluding one end portion are located in the accommodation space. The roller module may slide relative to the housing in the axial direction to be movable between the roller insertion position and the roller extraction position, so that the roller module is replaceable from the housing.

[0020] In an example, the roller module includes a heater module on which a heater may be mounted, and the support member has a hole into which the heater module may be inserted. The heater module may be slidable along the hole between a heater insertion position, where the heater module engages the hole, and a heater extraction position, where the heater module may be separated from the support member. The heater module may be slidable relative to the support member of the roller module to be movable between the heater insertion position and the heater extraction position, so that the heater module is separable from the roller module. In various examples of the image forming apparatus and the fixing device, a part of the fixing device is replaceable. As an example, at least one of the fixing unit, the roller module, or the heater module that are a part of the fixing device is replaceable.

[0021] Hereinafter, an image forming apparatus of an example will be described with reference to the drawings. In the description with reference to the drawings, the same or equivalent elements are denoted by the same reference signs, and a duplicated description may be appropriately omitted. The depiction of the drawings may be partially simplified or exaggerated for ease of understanding, and dimensional ratios and the like are not limited to those specified in the drawings.

[0022] FIG. 1 is a schematic view of an image forming apparatus 1 according to an example. As illustrated in FIG. 1 , the image forming apparatus 1 is an apparatus that uses toners of four colors such as magenta, yellow, cyan, and black to form a color image. The image forming apparatus 1 may include a conveying device 10, a plurality of image carriers 20, a plurality of developing devices 30, a transfer device 40, a fixing device 50, an output device 70, and a controller 71 .

[0023] The conveying device 10 is to convey a sheet M that is a recording medium on which an image is to be formed, along a conveyance path 11. The sheets M may be stacked and accommodated in a cassette 12 to be picked up and conveyed by a sheet feeding roller.

[0024] An electrostatic latent image may be formed on a surface (e.g., a peripheral surface) of each of the plurality of image carriers 20. The image forming apparatus 1 includes image carriers 20M, 20Y, 20C, and 20K as the plurality of image carriers 20. The image carrier 20M is to form an electrostatic latent image to form a magenta toner image. The image carrier 20Y is to form an electrostatic latent image to form a yellow toner image. The image carrier 20C is to form an electrostatic latent image to form a cyan toner image. The image carrier 20K is to form an electrostatic latent image to form a black toner image. Since the image carriers 20M, 20Y, 20C, and 20K have the same configuration, unless otherwise specified, the image carriers 20M, 20Y, 20C, and 20K will be collectively described as the image carrier 20. The image carrier 20 is also referred to an electrostatic latent image carrier, a photosensitive drum, or the like.

[0025] The plurality of developing devices 30 are to develop the electrostatic latent images formed on the surfaces of the respective image carriers 20M, 20Y, 20C, and 20K, to form toner images. The image forming apparatus 1 includes developing devices 30M, 30Y, 30C, and 30K as the plurality of developing devices 30. The developing device 30M is disposed on a periphery of the image carrier 20M to develop the electrostatic latent image formed on the image carrier 20M. The developing device 30Y is disposed on a periphery of the image carrier 20Y to develop the electrostatic latent image formed on the image carrier 20Y. The developing device 30C is disposed on a periphery of the image carrier 20C to develop the electrostatic latent image formed on the image carrier 20C. The developing device 30K is disposed on a periphery of the image carrier 20K to develop the electrostatic latent image formed on the image carrier 20K. Since the developing devices 30M, 30Y, 30C, and 30K have the same configuration, unless otherwise specified, the developing devices 30M, 30Y, 30C, and 30K will be collectively described as the developing device 30. [0026] The transfer device 40 is to convey and transfer the toner image developed by each of the developing devices 30M, 30Y, 30C, and 30K, on to the sheet M. The transfer device 40 may include a transfer belt 41 , primary transfer rollers 42M, 42Y, 42C, and 42K, and secondary transfer rollers 43 and 44. The primary transfer rollers 42M, 42Y, 42C, and 42K are to primarily transfer the toner images from the respective image carriers 20M, 20Y, 20C, and 20K on to the transfer belt 41. The secondary transfer rollers 43 and 44 are to secondarily transfer the toner images from the transfer belt 41 on to the sheet M.

[0027] The fixing device 50 is to heat and press the sheet M on to which the toner images are transferred from the transfer belt 41 , to fix the toner images on the sheet M to the sheet M. For example, the fixing device 50 is to apply heat and pressure to the sheet M conveyed from a secondary transfer region 14 where the secondary transfer rollers 43 and 44 are provided, to melt and fix the layered toner images to the sheet M. Examples of the fixing device 50 will be described later.

[0028] The output device 70 is to discharge the sheet M to which the toner images are fixed by the fixing device 50, to the outside of the image forming apparatus 1 .

[0029] The controller 71 may be an electronic control unit including a central control unit (CPU), a read only memory (ROM), a random access memory (RAM), and the like. The controller 71 is to load a program stored in the ROM to the RAM and cause the CPU to execute the program to control the image forming apparatus 1. The controller 71 may include a plurality of electronic control units or may include a single electronic control unit. The controller 71 may perform various control in the image forming apparatus 1 .

[0030] FIG. 2 is a view schematically illustrating a cross-section of the fixing device 50 in the image forming apparatus of FIG. 1 according to an example. As illustrated in FIGS. 1 and 2, the fixing device 50 includes a fixing unit 51 to heat the sheet M and to fix the toner images to the sheet M, and a pressure roller 52 to press the fixing unit 51 . The fixing unit 51 may include, for example, a fixing belt. A fixing nip portion 55 to heat and press the sheet M passing through the fixing nip portion 55 may be formed between the fixing unit 51 and the pressure roller 52. For example, the fixing device 50 may include guide members 53 and 54 to guide the sheet M to the fixing nip portion 55, and conveying rollers 56b and 56c to convey the sheet M from the fixing nip portion 55. The sheet M that has passed between the conveying roller 56b and the conveying rollers 56c may be discharged to the outside of the fixing device 50.

[0031] FIG. 3 is a perspective view illustrating the fixing device 50 of FIG.

2 according to an example. As illustrated in FIGS. 2 and 3, the fixing device 50 includes a housing 57 to accommodate the fixing unit 51 , the pressure roller 52, the guide members 53 and 54, and the conveying rollers 56b and 56c. The fixing unit 51 has a cylindrical shape, and an axial direction D1 in which an axis of the fixing unit 51 extends coincides with a longitudinal direction of the housing 57. The housing 57 has, for example, a rectangular box shape extending in the axial direction D1 and in a first direction D2 and a second direction D3 intersecting the axial direction D1. The first direction D2 is, for example, a width direction of the housing 57. The second direction D3 is a direction intersecting both the axial direction D1 and the first direction D2 and is, for example, a height direction of the housing 57. The housing 57 includes, for example, a top plate portion 57b and a side plate portion 57c that may be implemented as one component. In the fixing device 50, various components such as the fixing unit 51 are replaceable without opening the top plate portion 57b and the side plate portion 57c.

[0032] FIG. 4 is a perspective view illustrating a state where a roller module is extracted from the fixing device of FIG. 3 according to an example. As illustrated in FIGS. 3 and 4, the fixing device 50 includes a roller module 80 that is replaceable with respect to the housing 57. For example, the roller module 80 that is a part of the fixing device 50 is replaceable. The housing 57 has an accommodation space 58 in which the roller module 80 may be accommodated. The roller module 80 includes the fixing unit 51 extending in the axial direction D1 and a support member 82 to rotatably support the fixing unit 51. The support member 82 may be put inside the fixing unit 51 having a cylindrical shape to support the fixing unit 51 . The support member 82 extends in the axial direction D1 inside the fixing unit 51. The roller module 80 is slidable along the axial direction D1 between a roller insertion position, where the roller module 80 is located in the accommodation space 58, and a roller extraction position, where the roller module 80 is extracted from the housing 57. For example, the roller module 80 is slidable along the axial direction D1 between the roller insertion position, where at least a part of the roller module 80 is located in the accommodation space 58 of the housing 57 (the entirety or a part of the roller module 80 is located in the accommodation space 58), and the roller extraction position, where the roller module 80 is separated from the housing 57.

[0033] FIG. 5 is a perspective view illustrating a state where a heater module is extracted from a belt module of the roller module 80 of FIG. 4 according to an example. As illustrated in FIGS. 4 and 5, the roller module 80 may include a heater module 83 that is replaceable and that is to heat the fixing unit 51 . In an example, the support member 82 has a hole 82s extending in the axial direction D1 . The heater module 83 may have a shape extending in the axial direction D1 . The heater module 83 may be put into the hole 82s. The heater module 83 is insertable into and removable from the hole 82s. The heater module 83 is slidable along the axial direction D1 between a heater insertion position, where the heater module 83 is inserted into the hole 82s of the support member 82, and a heater extraction position, where the heater module 83 is separated from the support member 82. For example, the roller module 80 may include a belt module 85 including the fixing unit 51 and the support member 82, and the heater module 83 including a heater 83b. The heater module 83 is removable from the belt module 85 in the axial direction D1. For example, the heater module 83 that is a part of the fixing device 50 is replaceable.

[0034] FIG. 6 is a cross-sectional view of the roller module 80 of FIG. 4 according to an example. In more detail, FIG. 6 illustrates a cross-sectional view of the roller module based on the roller module 80 being cut along a plane orthogonal to the axial direction D1. As illustrated in FIGS. 5 and 6, the support member 82 includes a base frame 82b located inside the fixing unit 51 having a cylindrical shape, a base holder 82c located between the base frame 82b and the heater module 83, and fitting portions 82d formed at end portions of the roller module 80 in the axial direction D1 . The base frame 82b includes, for example, a pair of side portions 82f that extend in the first direction D2 and that are arranged along the second direction D3, and a top plate portion 82g extending in the second direction D3 between the pair of side portions 82f. The base holder 82c includes, for example, a center portion 82h that is put between the pair of side portions 82f, and a pair of extending portions 82t extending in the second direction D3 from end portions of the center portion 82h opposite the top plate portion 82g. [0035] The heater module 83 includes the heater 83b and a heater holder 83c to hold the heater 83b. The heater 83b may be, for example, a planar heater. The base holder 82c may be provided between the heater holder 83c and the base frame 82b. A pair of base frames 82b (e.g., side portions 82f) may be disposed side by side along the second direction D3 that is a width direction of the heater 83b, above the heater holder 83c.

[0036] FIG. 7 is an enlarged cross-sectional view of the base frame 82b, the base holder 82c, and the heater holder 83c of the roller module of FIG. 6 according to an example. As illustrated in FIGS. 6 and 7, a distance A between inner surfaces 82j of the pair of base frames 82b is smaller than a width B of the heater holder 83c. Based on being viewed along the axial direction D1 , for example, the heater holder 83c has an inverted T shape. A dividing line X may be formed between the heater holder 83c and the base holder 82c, and the heater module 83 is separable from the support member 82 through the dividing line X. [0037] For example, the heater holder 83c may include a holding portion 83g that is to hold the heater 83b while facing the fixing unit 51 , and a protruding portion 83h to protrude from the holding portion 83g opposite the fixing unit 51 . The dividing line X may include a first dividing line X1 extending in the first direction D2 from an end portion of the protruding portion 83h in the second direction D3, a second dividing line X2 extending from a lower end of the first dividing line X1 to opposite end sides in the second direction D3, and a third dividing line X3 extending in the first direction D2 from an end portion of the second dividing line X2 opposite the first dividing line X1 .

[0038] FIG. 8 is a perspective view schematically illustrating an internal structure of the housing 57 and the roller module 80 of the fixing device of FIG. 3 according to an example. As illustrated in FIG. 8, the housing 57 may include a rail 59 extending in the accommodation space 58, and a roller holder 60 having a hole portion 61 to hold the roller module 80 in the accommodation space 58. The rail 59 may include a guide rail extending along the axial direction D1 in the accommodation space 58. The roller module 80 is to move along the rail 59 to be removable with respect to the accommodation space 58. The support member 82 of the roller module 80 is to contact the rail 59, and the support member 82 is to pass through the hole portion 61 of the roller holder 60 in the axial direction D1 . [0039] For example, the roller holder 60 may be provided in the accommodation space 58 of the housing 57. The roller holder 60 may be attached to the rail 59 extending along the axial direction D1 in the accommodation space 58. In addition, the roller holder 60 may be provided on a wall of the housing 57. The roller holder 60 may include the hole portion 61 into which the roller module 80 may be inserted along the axial direction D1 . For example, the roller holder 60 may be provided at each of one end and another end, opposite to the one end, of the rail 59 in the axial direction D1 . The roller module 80 may be inserted into the hole portion 61 of the roller holder 60 located at the one end (e.g., right side in FIG. 8) of the rail 59, and may be fitted to the hole portion 61 of the roller holder 60 located at the other end (e.g., left side in FIG. 8) of the rail 59. The fitting portions 82d formed at the end portions of the roller module 80 in the axial direction D1 may be fitted to the hole portions 61 of the respective roller holders

60. As described above, the roller module 80 may be held by the roller holders 60 in a state where the fitting portions 82d are fitted to the respective hole portions

61.

[0040] The fitting portions 82d may each include, for example, a pair of first side wall portions 82k extending in both the axial direction D1 and the first direction D2 and being arranged along the second direction D3, a second side wall portion 82p to connect the pair of first side wall portions 82k to each other, and a pair of projecting portions 82q to project from upper ends of the first side wall portions 82k to the opposite end sides in the second direction D3. The second side wall portion 82p may extend in both the first direction D2 and the second direction D3.

[0041] As illustrated in FIG. 6, based on being viewed along the axial direction D1 , the fitting portions 82d may each include, for example, a guide 82r having a T shape. The guide 82r may extend in the axial direction D1. The guide 82r is attachable to and removable from the rail 59. The roller module 80 is to slide relative to the housing 57 along the axial direction D1 in a state where the guides 82r are mounted on the rail 59. For example, the guides 82r may each include the pair of projecting portions 82q to project to the opposite end sides in the second direction D3 based on being viewed along the axial direction D1.

[0042] The rail 59 may be, for example, a C channel. In this case, the rail 59 may include a first plate portion 59b extending in the second direction D3, a pair of second plate portions 59c extending downward from opposite ends of the first plate portion 59b in the second direction D3, and a pair of third plate portions 59d to protrude from lower ends of the second plate portions 59c to a center side of the rail 59 in the second direction D3. The fitting portions 82d (e.g., guides 82r) may each pass through a space inside the rail 59 along the axial direction D1 , the space being surrounded by the first plate portion 59b, the pair of second plate portions 59c, and the pair of third plate portions 59d. In this case, the support member 82 is slidable relative to the rail 59 along the axial direction D1 in a state where the projecting portions 82q are placed on the respective third plate portions 59d.

[0043] FIG. 9 is a side view illustrating the roller module 80 of FIG. 4 according to an example. FIG. 10 is a side view illustrating the belt module 85 of the roller module 80 of FIG. 9 according to an example. FIG. 11 is a side view illustrating the heater module 83 of the roller module 80 of FIG. 9 according to an example. The roller module 80 is insertable and removable with respect to the housing 57 along the axial direction D1. The heater module 83 is separable with respect to the belt module 85. Namely, the heater module 83 is insertable and removable with respect to the roller module 80 (e.g., belt module 85) along the axial direction D1.

[0044] The heater module 83 may include, for example, the heater 83b, the heater holder 83c, a sensor 83d to detect a temperature of the fixing unit 51 , and a thermostat 83f. The heater holder 83c may hold the heater 83b, the sensor 83d, and the thermostat 83f. The heater holder 83c may have a shape extending along the axial direction D1 . For example, the heater 83b may be disposed at one end of the heater holder 83c, and the thermostat 83f may be disposed on another end side of the heater holder 83c. The sensor 83d may be disposed between the heater 83b and the thermostat 83f.

[0045] Example actions and effects that may be obtained from the image forming apparatus 1 will be described. As illustrated in FIGS. 5, 6, and 8, in the image forming apparatus 1 , the roller module 80 may slide along the axial direction D1 between the roller insertion position, where the roller module 80 is located in the accommodation space 58 of the housing 57, and the roller extraction position, where the roller module 80 may be extracted from the housing 57. Therefore, the replacement of the roller module 80 can be easily performed by extracting the roller module 80 from the housing 57. For example, in the related art, the top plate portion 57b and the like of the housing 57 are opened and the roller module 80 is removed. However, in the example image forming apparatus 1 , since the roller module 80 is insertable and removable along the axial direction D1 without opening the top plate portion 57b or the side plate portion 57c, the replacement of the roller module 80 can be easily performed. Further, since there is no need to disassemble the top plate portion 57b and the like in a situation in which the roller module 80 is replaced, the position accuracy of the housing 57 and internal components of the housing 57 can be secured.

[0046] The heater module 83 is slidable along the hole 82s between the heater insertion position, where the heater module 83 engages the hole 82s of the support member 82, and the heater extraction position, where the heater module 83 may be separated from the support member 82. In addition, the roller module 80 is separable into the belt module 85 and the heater module 83. Therefore, the belt module 85 or the heater module 83 is individually replaceable. The support member 82 may include the guides 82r that may extend in the axial direction D1 and that are to slide the roller module 80 relative to the housing 57 in the axial direction D1 such that the roller module 80 is detachably accommodated in the housing 57. The insertion and removal of the roller module 80 with respect to the housing 57 can be more smoothly performed by the guides 82r.

[0047] The roller module 80 is to move along the rail 59 that is a guide rail that is located in the housing 57, to be removable with respect to the accommodation space 58. Therefore, the roller module 80 is insertable and removable along the rail 59 with respect to the housing 57, so that the insertion and removal of the roller module 80 with respect to the housing 57 can be stabilized. As a result, the insertion and removal of the roller module 80 with respect to the housing 57 can be more smoothly performed.

[0048] The roller module 80 may include the fitting portions 82d located at the end portions of the roller module 80 in the axial direction D1 . The roller module 80 may be held by the roller holders 60 in a state where the fitting portions 82d are fitted to the hole portions 61 of the respective roller holders 60. Therefore, the roller module 80 can be inserted into the hole portions 61 and the roller module 80 can be held by the roller holders 60, so that a structure for holding the roller module 80 inside the housing 57 can be simplified. In addition, since the hole portions 61 can hold the roller module 80 by allowing the roller module 80 to pass therethrough, the roller module 80 can be easily held by the housing 57. The roller holder 60 may be provided at the one end of the rail 59 in the axial direction D1 . In addition, the roller holder 60 may be provided at each of the one end and another end of the rail 59 in the axial direction D1. In this case, since the roller holder 60 is provided at at least one of the one end and the other end of the rail 59, the roller module 80 can be held by the roller holder 60 provided at the end portion of the rail 59.

[0049] The support member 82 may include the base frame 82b located inside the fixing unit 51 having a cylindrical shape, the base holder 82c located between the base frame 82b and the heater module 83, and the fitting portions 82d located at the end portions of the roller module 80 in the axial direction D1. As illustrated in FIGS. 6 and 7, the pair of base frames 82b may be disposed side by side along the width direction of the heater holder 83c above the heater holder 83c, and the distance A between the inner surfaces 82j of the pair of base frames 82b may be smaller than the width B of the heater holder 83c. As a result, a load C of the base frame 82b can be stably transmitted to the fixing unit 51 through the heater holder 83c.

[0050] As illustrated in FIGS. 9 and 11 , the heater module 83 may include the heater 83b, the sensor 83d to detect a temperature of the fixing unit 51 , the thermostat 83f, and the heater holder 83c to hold the heater 83b, the sensor 83d, and the thermostat 83f. As described above, the heater module 83 may be separable from the belt module 85. Therefore, the belt module 85 is replaceable while the heater 83b, the sensor 83d, and the thermostat 83f may be left in the heater module 83.

[0051] A modification example of the image forming apparatus will be described with reference to FIG. 12. The description related to the following modification example can also be appropriately combined with the image forming apparatus 1 described above. FIG. 12 is a cross-sectional view of the base frame 82b, the base holder 82c, and the heater holder 83c of a roller module of FIG. 7 according to a modification example. As illustrated in FIG. 12, a gap 86 may be formed between the base holder 82c and the heater holder 83c. The gap 86 may be provided to reduce a contact area of the heater holder 83c with respect to the base holder 82c. For example, the gap 86 may include a pair of first gaps 86b located on opposite respective sides of the protruding portion 83h in the second direction D3, and a pair of second gaps 86c located on opposite respective sides of the holding portion 83g in the second direction D3. As described above, the gap 86 may reduce the contact area of the heater holder 83c with respect to the base holder 82c. As a result, thermal energy generated from the heater 83b can be prevented from being transferred to the support member 82 through the heater holder 83c, and the transfer of heat from the heater 83b to the fixing unit 51 can be efficiently performed. Therefore, the energy saving performance of the heater 83b can be improved.

[0052] FIG. 13 is a view schematically illustrating the belt module 85 of the roller module 80 according to the modification example. FIG. 14 is a view schematically illustrating the heater module 83 of the roller module 80 according to the modification example. For example, the roller module 80 may have one end 80b and another end 80c in the axial direction D1. The roller module 80 may be insertable into the accommodation space 58 of the housing 57 described above from the one end 80b, and for example, a width of the one end 80b is narrower than a width of the other end 80c. [0053] The heater module 83 may have one end 83j and another end 83k in the axial direction D1 . The heater module 83 may be insertable into the support member 82 of the roller module 80 from the one end 83j . A width E3 of the one end 83j of the heater module 83 may be narrower than a width E4 of the other end 83k. Therefore, the insertion of the heater module 83 can be more smoothly performed by inserting the heater module 83 into the support member 82 from the one end 83j . In addition, the belt module 85 of the roller module 80 includes a bottom portion 85b located at one end in the axial direction D1 , and an opening 85c located at another end in the axial direction D1 , and a width E2 of the opening 85c may be wider than a width E1 of the bottom portion 85b. The heater module 83 may be insertable into the inside of the belt module 85 from the opening 85c. In this case, as described above, since the width E2 of the opening 85c is wider than the width E1 of the bottom portion 85b, the insertion of the heater module 83 into the belt module 85 can be smoothly performed.

[0054] FIG. 15 is a perspective view illustrating the roller module 80 of the modification example. FIG. 16 is a perspective view illustrating a state where the fixing unit 51 is removed from a support member of the roller module 80 of FIG. 15 according to an example. As illustrated in FIGS. 15 and 16, in the roller module 80, the fixing unit 51 may be attachable to and removable from the support member 82. The support member 82 may include, for example, an attachment portion 82v having a shape extending along the axial direction D1 , and the fitting portions 82d located at opposite respective ends of the attachment portion 82v, and each of the fitting portions 82d may be attachable to and removable from the attachment portion 82v. For example, one of a pair of the fitting portions 82d may be removed from the attachment portion 82v to remove the fixing unit 51 from the attachment portion 82v. In that case, the new fixing unit 51 may be mountable on the support member 82 by, for example, applying grease to the attachment portion 82v and inserting the attachment portion 82v into the fixing unit 51 . As described above, the support member 82 may include the attachment portion 82v to which the fixing unit 51 is detachably attached, and the fixing unit 51 may be replaceable. Namely, the fixing unit 51 that is a part of the fixing device 50 may be replaceable.

In this case, the fixing unit 51 may be replaceable from the roller module 80. [0055] It should be understood that all of the examples, advantages, and features described in the specification are not necessarily achieved by or included in any one specific example. In effect, various examples have been described in the specification, but it should be apparent that the dispositions and details can also be changed in other examples.

[0056] For example, an example in which the fixing unit 51 is a fixing belt has been described above. However, the fixing unit may not be a fixing belt but may be, for example, a fixing roller. In addition, an example in which the rail 59 is a C channel has been described above. However, the rail may have a shape different from a C channel, and the shape of the rail is not particularly limited. As described above, this application claims all changes and modifications included in the concept and scope of the techniques under the protection claimed herein.