Heating device and image processing device

Abstract

To provide a heating device and an image processing device capable of suppressing irregularities of a temperature.SOLUTION: A heating device includes a rotary film, a first thermometer, a second thermometer, a heating element, a support member, and a stay. The rotary film has a length in a first direction, and is rotated around an axis parallel with the first direction. The first thermometer abuts on the inner surface of the rotary film. The second thermometer abuts on the inner surface of the rotary film in a position close to the center in the first direction of the rotary film and deviating in the first direction from the center of the rotary film. The heating element has a length in the first direction, and has a width in a second direction that coincides with the rotary direction of the rotating film while being orthogonal to the first direction. The support member holds the heating element in a position fixed to the rotary film. The stay supports the support member, the first thermometer, and the second thermometer, extends in the first direction, and is surrounded by the rotary film.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] FIELD An embodiment of the present invention relates to a heating device and an image processing device. [Background technology]

[0002] Image forming apparatuses that form images on sheets are used as image processing apparatuses. Image forming apparatuses have a heating device that fixes toner (recording material) onto a sheet. The heating device is required to suppress temperature unevenness. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-91499 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a heating device and an image processing device capable of suppressing temperature unevenness. [Means for solving the problem]

[0005] The heating device of the embodiment has a rotating film, a first thermometer, a second thermometer, a heating element, a support member, and a stay. The rotating film has a length in a first direction and rotates around an axis parallel to the first direction. The first thermometer contacts the inner surface of the rotating film. The second thermometer contacts the inner surface of the rotating film near the center of the rotating film in the first direction and offset from the center of the rotating film in the first direction. The heating element has a length in the first direction and a width in a second direction that is perpendicular to the first direction and coincides with the rotation direction of the rotating film. The support member holds the heating element in a fixed position relative to the rotating film. The stay supports the support member, the first thermometer, and the second thermometer, extends in the first direction, and is surrounded by the rotating film. [Brief description of the drawings]

[0006] [Figure 1] 1 is a schematic configuration diagram of an image processing apparatus according to an embodiment. [Diagram 2] FIG. 1 is a hardware configuration diagram of an image processing apparatus according to an embodiment. [Diagram 3] FIG. 2 is a front cross-sectional view of the heating device according to the first embodiment. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 6 is a front cross-sectional view of a heating device according to a second embodiment. [Figure 9] FIG. [Figure 10] FIG. 13 is a bottom view of a guide member in a first modified example of the second embodiment. [Figure 11] FIG. 13 is a bottom view of a guide member in a second modified example of the second embodiment. [Figure 12] FIG. 13 is a bottom view of a guide member in a third modified example of the second embodiment. [Figure 13] FIG. 11 is a front cross-sectional view of a heating device according to a third embodiment. [Figure 14] FIG. [Figure 15] FIG. [Figure 16] FIG. 13 is a bottom view of a support member in a first modified example of the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a heating device and an image processing device according to an embodiment will be described with reference to the drawings. 1 is a schematic diagram of an image processing apparatus according to an embodiment of the present invention, which is an image forming apparatus 1. The image forming apparatus 1 performs processing for forming an image on a sheet (paper) S. The image forming apparatus 1 includes a housing 10, a scanner section 2, an image forming unit 3, a sheet supply section 4, a conveying section 5, a paper discharge tray 7, a reversing unit 9, a control panel 8, and a control section 6.

[0008] The housing 10 forms the outer shape of the image forming apparatus 1 . The scanner unit 2 reads image information of an object to be copied as light and shade, and generates an image signal. The scanner unit 2 outputs the generated image signal to the image forming unit 3. The image forming unit 3 forms an output image (hereinafter referred to as a toner image) using a recording agent such as toner based on an image signal received from the scanner unit 2 or an image signal received from an external source. The image forming unit 3 transfers the toner image onto the surface of the sheet S. The image forming unit 3 applies heat and pressure to the toner image on the surface of the sheet S to fix the toner image to the sheet S. Details of the image forming unit 3 will be described later.

[0009] The sheet supply section 4 supplies the sheets S one by one to the conveying section 5 in accordance with the timing at which the image forming unit 3 forms a toner image. The sheet supply section 4 includes a sheet storage section 20 and a pickup roller . The sheet storage section 20 stores sheets S of a predetermined size and type. The pickup roller 21 picks up the sheets S one by one from the sheet storage unit 20. The pickup roller 21 supplies the picked-up sheets S to the conveying unit 5.

[0010] The conveying section 5 conveys the sheet S supplied from the sheet supplying section 4 to the image forming unit 3. The conveying section 5 includes a conveying roller 23 and a registration roller 24. The conveying roller 23 conveys the sheet S supplied from the pickup roller 21 to the registration roller 24. The conveying roller 23 abuts the leading edge of the sheet S in the conveying direction against the nip N of the registration roller 24. The registration rollers 24 adjust the position of the leading edge of the sheet S in the conveying direction by bending the sheet S at the nip N. The registration rollers 24 convey the sheet S in accordance with the timing at which the image forming unit 3 transfers a toner image onto the sheet S.

[0011] The image forming unit 3 will now be described. The image forming unit 3 includes a plurality of image forming sections 25, a laser scanning unit 26, an intermediate transfer belt 27, a transfer section 28, and a fixing device 30. The image forming unit 25 has a photoconductor drum 25d. The image forming unit 25 forms a toner image on the photoconductor drum 25d in response to an image signal from the scanner unit 2 or an external device. The image forming units 25Y, 25M, 25C, and 25K form toner images using yellow, magenta, cyan, and black toners, respectively.

[0012] A charger, a developer, and the like are arranged around the photoconductor drum 25d. The charger charges the surface of the photoconductor drum 25d. The developer contains a developer including yellow, magenta, cyan, and black toners. The developer develops the electrostatic latent image on the photoconductor drum 25d. As a result, a toner image made of the toners of each color is formed on the photoconductor drum 25d.

[0013] The laser scanning unit 26 scans the charged photoconductor drum 25d with a laser beam L to expose the photoconductor drum 25d. The laser scanning unit 26 exposes the photoconductor drums 25d of the image forming sections 25Y, 25M, 25C, and 25K of the respective colors with separate laser beams LY, LM, LC, and LK. As a result, the laser scanning unit 26 forms an electrostatic latent image on the photoconductor drum 25d.

[0014] The toner image on the surface of the photoconductor drum 25d is primarily transferred onto the intermediate transfer belt 27. The transfer unit 28 transfers the toner image, which has been primarily transferred onto the intermediate transfer belt 27, onto the front surface of the sheet S at a secondary transfer position. The fixing device 30 applies heat and pressure to the toner image transferred to the sheet S, thereby fixing the toner image to the sheet S. The fixing device 30 will be described in detail later.

[0015] The reversing unit 9 reverses the sheet S to form an image on the back side of the sheet S. The reversing unit 9 reverses the sheet S discharged from the fixing device 30 by switchback. The reversing unit 9 conveys the reversed sheet S toward the registration rollers 24. The sheet discharge tray 7 holds the sheet S on which an image has been formed and discharged. The control panel 8 is a part of an input unit through which an operator inputs information for operating the image forming apparatus 1. The control panel 8 has a touch panel and various hard keys. The control unit 6 controls each unit of the image forming apparatus 1 .

[0016] 2 is a hardware configuration diagram of an image processing apparatus according to an embodiment. The image forming apparatus 1 includes a CPU (Central Processing Unit) 91, a memory 92, an auxiliary storage device 93, and the like, which are connected via a bus, and executes a program. By executing the program, the image forming apparatus 1 functions as an apparatus including a scanner section 2, an image forming unit 3, a sheet supply section 4, a conveying section 5, a reversing unit 9, a control panel 8, and a communication section 90.

[0017] The CPU 91 functions as the control unit 6 by executing programs stored in the memory 92 and the auxiliary storage device 93. The control unit 6 controls the operation of each functional unit of the image forming apparatus 1. The auxiliary storage device 93 is configured using a storage device such as a magnetic hard disk device, a semiconductor storage device, etc. The auxiliary storage device 93 stores information. The communication unit 90 includes a communication interface for connecting the device to an external device, and communicates with the external device via the communication interface.

[0018] (First embodiment) The fixing device 30 will now be described in detail. 3 is a front cross-sectional view of the heating device of the first embodiment. The heating device of the first embodiment is a fixing device 30. The fixing device 30 has a pressure roller 30p and a film unit 30h.

[0019] The pressure roller 30p forms a nip N between itself and the film unit 30h (a heater unit 40 described later). The pressure roller 30p presses the toner image on the sheet S that has entered the nip N. The pressure roller 30p rotates to transport the sheet S. The pressure roller 30p has a core metal 32, an elastic layer 33, and a release layer (not shown).

[0020] The core 32 is formed into a cylindrical shape from a metal material such as stainless steel. Both axial ends of the core 32 are rotatably supported. The core 32 is driven to rotate by a motor (not shown). The core 32 abuts against a cam member (not shown). The cam member rotates to move the core 32 toward and away from the film unit 30h.

[0021] The elastic layer 33 is made of an elastic material such as silicone rubber, etc. The elastic layer 33 is formed on the outer circumferential surface of the core metal 32 with a constant thickness. The release layer (not shown) is formed of a resin material such as PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer), etc. The release layer is formed on the outer peripheral surface of the elastic layer 33. The hardness of the outer peripheral surface of the pressure roller 30p is desirably 40° to 70° when subjected to a load of 9.8 N using an ASKER-C hardness tester, thereby ensuring the area of ​​the nip N and the durability of the pressure roller 30p.

[0022] The pressure roller 30p can approach and move away from the film unit 30h by the rotation of a cam member. When the pressure roller 30p is brought close to the film unit 30h and pressed by a pressure spring, a nip N is formed. Meanwhile, when a jam of the sheet S occurs in the fixing device 30, the sheet S can be removed by moving the pressure roller 30p away from the film unit 30h. In addition, when the cylindrical film 35 is stopped from rotating, such as during sleep, plastic deformation of the cylindrical film 35 is prevented by moving the pressure roller 30p away from the film unit 30h.

[0023] The pressure roller 30p is rotated by a motor to rotate on its axis. When the pressure roller 30p rotates on its axis with the nip N formed, the cylindrical film 35 of the film unit 30h is rotated in the rotation direction R. The pressure roller 30p rotates on its axis with the sheet S disposed in the nip N, thereby conveying the sheet S in the conveying direction W.

[0024] The film unit 30h heats the toner image on the sheet S that has entered the nip N. The film unit 30h has a cylindrical film (cylindrical body) 35, a heater unit 40, a heat transfer member 49, a support member 70, a stay 38, a peeling plate 39, a temperature sensing element 60, and a film thermometer 64.

[0025] The cylindrical film 35 is formed in a cylindrical shape. The cylindrical film 35 has, in order from the inner periphery side, a base layer, an elastic layer, and a release layer. The base layer is formed in a cylindrical shape from a metal material such as nickel (Ni) or a resin material such as polyimide (PI). The elastic layer is laminated on the outer periphery surface of the base layer. The elastic layer is made of an elastic material such as silicone rubber. The release layer is laminated on the outer periphery surface of the elastic layer. The release layer is made of a material such as PFA resin.

[0026] Fig. 4 is a front cross-sectional view of the heater unit taken along line IV-IV in Fig. 5. Fig. 5 is a bottom view of the heater unit (viewed from the +z direction). Heater unit 40 has a substrate (heating element substrate) 41, a heating element set (heating element) 45, and a wiring set 55.

[0027] Substrate 41 is formed of a metal material such as stainless steel or a ceramic material such as aluminum nitride. Substrate 41 is formed in a long, thin rectangular plate shape. Substrate 41 is disposed radially inside tubular film 35. The longitudinal direction of substrate 41 is the axial direction of tubular film 35.

[0028] In the present application, the x-direction, y-direction, and z-direction are defined as follows. The y-direction is the longitudinal direction of the substrate 41. As described later, the +y-direction is the direction from the central heating element 45a toward the first end heating element 45b1. The x-direction is the lateral direction of the substrate 41, and the +x-direction is the conveying direction (downstream direction) of the sheet S. The z-direction is the normal direction of the substrate 41. The +z-direction is the direction in which the heating element set 45 is disposed relative to the substrate 41, and is the direction in which the first surface 40a in contact with the tubular film 35 in the heater unit 40 is disposed. The -z-direction is the direction opposite to the +z-direction, and is the direction in which the second surface 40b in contact with the heat transfer member 49 in the heater unit 40 is disposed. An insulating layer 43 is formed of a glass material or the like on the surface of the substrate 41 in the +z direction.

[0029] The heating element set 45 is disposed on the substrate 41 as shown in Fig. 5. The heating element set 45 is formed of a silver-palladium alloy or the like. The outer shape of the heating element set 45 is formed into a rectangular shape with the y direction as the longitudinal direction and the x direction as the transverse direction. The center 45c of the heating element set 45 in the x direction is disposed in the -x direction from the center 41c of the substrate 41 (heater unit 40) in the x direction.

[0030] The heating element set 45 has a plurality of heating elements 45b1, 45a, 45b2 arranged along the y direction. The heating element set 45 has a first end heating element 45b1, a central heating element 45a, and a second end heating element 45b2 arranged side by side in the y direction. The central heating element 45a is arranged in the center of the heating element set 45 in the y direction. The first end heating element 45b1 is arranged in the +y direction of the central heating element 45a, at the end of the heating element set 45 in the +y direction. The second end heating element 45b2 is arranged in the -y direction of the central heating element 45a, at the end of the heating element set 45 in the -y direction.

[0031] The heating element set 45 generates heat when electricity is applied. A sheet S having a small width in the y direction passes through the center of the fixing device 30 in the y direction. In this case, the control unit 6 causes only the center heating element 45a to generate heat. On the other hand, in the case of a sheet S having a large width in the y direction, the control unit 6 causes the entire heating element set 45 to generate heat. Therefore, the heating of the center heating element 45a, the first end heating element 45b1, and the second end heating element 45b2 is controlled independently of each other. The heating of the first end heating element 45b1 and the second end heating element 45b2 is similarly controlled.

[0032] 4, a heating element set 45 and a wiring set 55 are formed on the +z direction surface of the insulating layer 43. A protective layer 46 is formed of a glass material or the like so as to cover the heating element set 45 and the wiring set 55. The protective layer 46 improves the sliding property between the heater unit 40 and the tubular film 35. An insulating layer may be formed in the -z direction of the substrate 41, similar to the insulating layer 43 formed in the +z direction of the substrate 41. A protective layer may be formed in the -z direction of the substrate 41, similar to the protective layer 46 formed in the +z direction of the substrate 41. This suppresses warping of the substrate 41.

[0033] 3, the heater unit 40 is disposed inside the tubular film 35. Grease (not shown) is applied to the inner circumferential surface of the tubular film 35. A first surface 40a of the heater unit 40 in the +z direction contacts the inner circumferential surface of the tubular film 35 via the grease. When the heater unit 40 generates heat, the viscosity of the grease decreases. This ensures the sliding properties between the heater unit 40 and the tubular film 35.

[0034] The heat transfer member 49 is made of a metal material with high thermal conductivity, such as copper. The outer shape of the heat transfer member 49 is the same as the outer shape of the substrate 41 of the heater unit 40. The heat transfer member 49 is disposed in contact with at least a part of the second surface 40b of the heater unit 40 in the -z direction.

[0035] The support member 70 is made of a resin material such as a liquid crystal polymer. The support member 70 is formed so as to cover both ends of the heater unit 40 in the -z direction and the x direction. The support member 70 supports the heater unit 40 via the heat transfer member 49. The support member 70 supports the inner circumferential surface of the tubular film 35 at both ends of the heater unit 40 in the x direction. Details of the support member 70 will be described later.

[0036] When the sheet S passing through the fixing device 30 is heated, a temperature distribution occurs in the heater unit 40 according to the size of the sheet S. If the heater unit 40 becomes locally hot, there is a possibility that the temperature will exceed the heat resistance temperature of the support member 70 made of a resin material. The heat transfer member 49 averages the temperature distribution of the heater unit 40. This ensures the heat resistance of the support member 70.

[0037] The stay 38 is formed from a steel plate material or the like. A cross section of the stay 38 perpendicular to the y direction is formed into a U-shape. The stay 38 is attached in the -z direction of the support member 70 so that the opening of the U-shape is blocked by the support member 70. The stay 38 extends in the y direction. Both ends of the stay 38 in the y direction are fixed to the housing of the image forming device 1. This allows the film unit 30h to be supported by the image forming device 1. The stay 38 improves the bending rigidity of the film unit 30h. Flanges (not shown) that regulate the movement of the tubular film 35 in the y direction are attached near both ends of the stay 38 in the y direction.

[0038] Peeling plate 39 is positioned away from nip N on the downstream side in the conveying direction W. The end of peeling plate 39 in the -x direction tapers toward nip N and is positioned close to tubular film 35. Sheet S pressed at nip N is discharged from nip N in a state where it is attached to tubular film 35. Peeling plate 39 assists in peeling sheet S from tubular film 35.

[0039] The temperature sensing element 60 is disposed in the -z direction of the heater unit 40. The temperature sensing element 60 is disposed on the surface of the heat transfer member 49 in the -z direction. The temperature sensing element 60 is disposed inside a hole penetrating the support member 70 in the z direction. The temperature sensing element 60 is a heater thermometer 62 and a thermostat (shutoff device) 68. For example, the heater thermometer 62 is a thermistor.

[0040] The heater thermometer 62 detects the temperature of the heater unit 40 via the heat transfer member 49. The control unit 6 (see FIG. 1) controls the power supply to the heat generating element set 45 based on the temperature detected by the heater thermometer 62 when the fixing device 30 is started up. When the temperature of heater unit 40 detected via heat transfer member 49 exceeds a predetermined temperature, thermostat 68 cuts off the supply of electricity to heating element set 45. As a result, excessive heating of tubular film 35 by heater unit 40 is suppressed.

[0041] 3, film thermometer 64 abuts against the inner circumferential surface of tubular film 35. Film thermometer 64 detects the temperature of tubular film 35. The control unit 6 controls the power supply to the heating element set 45 based on the temperature detected by the film thermometer 64 when the fixing device 30 is in operation.

[0042] The support member 70 will now be described in detail. 3, the support member 70 has a back surface member 74, an upstream side member 75u, and a downstream side member 75d. The back surface member 74 is disposed so as to cover the heater unit 40 in the -z direction. The back surface member 74 supports the heater unit 40 via the heat transfer member 49. The upstream member 75u and the downstream member 75d are integrally formed with the back member 74 as part of the support member 70. Note that the support member 70 may be formed by combining the back member 74, the upstream member 75u, and the downstream member 75d, which are each formed separately.

[0043] The upstream member 75u is disposed upstream of the heater unit 40 in the rotation direction R of the tubular film 35. The upstream member 75u extends in the +z direction from the -x direction end of the backing member 74. The +z direction surface of the upstream member 75u is formed into a curved surface that follows the inner surface of the tubular film 35, and is disposed along the inner surface of the tubular film 35. The upstream member 75u supports the tubular film 35, stabilizing the entry of the sheet S into the nip N.

[0044] The downstream member 75d is disposed downstream of the heater unit 40 in the rotation direction R of the tubular film 35. The downstream member 75d extends in the +z direction from the end of the back member 74 in the +x direction. The surface of the downstream member 75d in the +z direction is formed into a curved surface that follows the inner surface of the tubular film 35, and is disposed along the inner surface of the tubular film 35. The downstream member 75d supports the tubular film 35, so that the tubular film 35 is disposed close to the peeling plate 39. The sheet S discharged from the nip N is unlikely to get between the tubular film 35 and the peeling plate 39. The sheet S is separated from the tubular film 35 by the peeling plate 39. This improves the peelability of the sheet S.

[0045] The upstream member 75u has a first upstream rib 71u as the upstream rib 7u. The first upstream rib 71u extends in the circumferential direction of the tubular film 35. The first upstream rib 71u extends from the upstream member 75u to the upstream side in the rotation direction R of the tubular film 35. The first upstream rib 71u is capable of abutting against the inner surface of the tubular film 35.

[0046] The downstream member 75d has a first downstream rib 71d as the downstream rib 7d. The first downstream rib 71d extends in the circumferential direction of the tubular film 35. The first downstream rib 71d extends downstream of the downstream member 75d in the rotational direction R of the tubular film 35. The first downstream rib 71d is capable of abutting against the inner surface of the tubular film 35.

[0047] 6 is a side view of the periphery of the support member. The first downstream rib 71d is formed in a plate shape with the thickness direction being in the y direction. A slit is formed in the center of the first downstream rib 71d in the y direction. This reduces the contact area between the first downstream rib 71d and the tubular film 35. The first upstream rib 71u is formed in the same manner as the first downstream rib 71d. The first upstream rib 71u and the first downstream rib 71d guide the rotation of the tubular film 35. The tubular film 35 rotates while being held in a predetermined shape by the first upstream rib 71u and the first downstream rib 71d.

[0048] FIG. 7 is a bottom view of the periphery of the support member. A plurality of first upstream ribs 71u are arranged side by side in the y direction. A plurality of first downstream ribs 71d are arranged side by side in the y direction. The first downstream rib 71d is arranged at a position different from the first upstream rib 71u in the y direction. That is, at least a portion of the first upstream rib 71u does not overlap with the first downstream rib 71d in the y direction. At least a portion of the first downstream rib 71d does not overlap with the first upstream rib 71u in the y direction. The first upstream rib 71u and the first downstream rib 71d have portions that do not overlap with each other in the y direction. It is desirable that the first upstream rib 71u and the first downstream rib 71d do not have portions that overlap with each other in the y direction.

[0049] As described above, the fixing device 30 heats and pressurizes the toner image on the sheet S that has entered the nip N, thereby fixing the toner image to the sheet S. It is desirable that the temperature of the tubular film 35 is uniform in the y direction. The rotation of the tubular film 35 is guided by the contact with the first upstream rib 71u and the first downstream rib 71d. The contact with the first upstream rib 71u and the first downstream rib 71d transfers the heat of the tubular film 35 to the first upstream rib 71u and the first downstream rib 71d. If the first upstream rib 71u and the first downstream rib 71d were located at the same position in the y direction, the temperature of the tubular film 35 would drop significantly at that position. This would cause temperature unevenness in the fixing device 30.

[0050] In contrast, the first upstream rib 71u and the first downstream rib 71d in this embodiment are disposed at different positions in the y direction. The position in the y direction where the tubular film 35 abuts against the first upstream rib 71u is different from the position in the y direction where the tubular film 35 abuts against the first downstream rib 71d. The temperature drop of the tubular film 35 due to the abutment between the first upstream rib 71u and the first downstream rib 71d is dispersed in the y direction. This suppresses temperature unevenness in the fixing device 30. As a result, the print quality of the fixing device 30 improves.

[0051] As shown in FIG. 7, a boundary portion 45s is formed between the central heating element 45a and the first end heating element 45b1 of the heater unit 40. A boundary portion 45s is also formed between the central heating element 45a and the second end heating element 45b2. The boundary portion 45s is formed parallel to the x direction. The boundary portion 45s may be formed intersecting the x direction. The first upstream rib 71u and the first downstream rib 71d are disposed at a position different from the boundary portion 45s in the y direction. That is, the boundary portion 45s, the first upstream rib 71u, and the first downstream rib 71d have portions that do not overlap with each other in the y direction. It is preferable that the boundary portion 45s, the first upstream rib 71u, and the first downstream rib 71d do not have portions that overlap with each other in the y direction.

[0052] Heater unit 40 does not generate heat at boundary portion 45s. The temperature of tubular film 35 at the same position in the y direction as boundary portion 45s is lower than the temperature at other positions. If first upstream rib 71u and first downstream rib 71d were located at the same position in the y direction as boundary portion 45s, the temperature of tubular film 35 would drop significantly at that position. This would cause temperature unevenness in fixing device 30. In contrast, the first upstream rib 71u and the first downstream rib 71d of the present embodiment are disposed at a position different from the boundary portion 45s in the y direction. A decrease in temperature of the tubular film 35 due to contact with the first upstream rib 71u and the first downstream rib 71d occurs at a position different from the boundary portion 45s. As a result, temperature unevenness in the fixing device 30 is suppressed.

[0053] As described above in detail, the fixing device 30 of the present embodiment includes the tubular film 35, the heater unit 40, the upstream member 75u, the downstream member 75d, the upstream rib 7u, and the downstream rib 7d. The heater unit 40 is disposed along the inner surface of the tubular film 35, the axial direction of the tubular film 35 is the longitudinal direction (y direction), and the heater unit 40 includes the heating element set 45. The upstream member 75u is disposed along the inner surface of the tubular film 35. The upstream member 75u is disposed upstream of the heater unit 40 in the rotation direction R of the tubular film 35. The downstream member 75d is disposed along the inner surface of the tubular film 35 and downstream of the heater unit 40 in the rotation direction R of the tubular film 35. The upstream ribs 7u are formed on the upstream member 75u, extend in the circumferential direction of the tubular film 35, are capable of contacting the inner surface of the tubular film 35, and are disposed side by side in the y direction. Downstream rib 7d is formed on downstream member 75d, extends in the circumferential direction of tubular film 35, and is capable of contacting the inner surface of tubular film 35. Downstream rib 7d is arranged in a different position in the y direction from upstream rib 7u. As a result, the temperature drop of tubular film 35 caused by contact with upstream rib 7u and downstream rib 7d is dispersed in the y direction, thereby suppressing temperature unevenness in fixing device 30.

[0054] The upstream rib 7u has a first upstream rib 71u extending upstream in the rotation direction R of the tubular film 35 from the upstream member 75u. The downstream rib 7d has a first downstream rib 71d extending downstream in the rotation direction R of the tubular film 35 from the downstream member 75d. First upstream rib 71u and first downstream rib 71d guide the rotation of tubular film 35. This prevents deformation of tubular film 35 and improves reliability.

[0055] The heat generating element set 45 has a plurality of heat generating elements 45a, 45b1, 45b2 arranged side by side in the y direction. The upstream rib 7u and the downstream rib 7d are arranged at positions different from the boundary portion 45s of the plurality of heat generating elements 45a, 45b1, 45b2 in the y direction. As a result, the temperature drop of tubular film 35 due to contact with upstream rib 7u and downstream rib 7d occurs at a position other than boundary portion 45s. Therefore, temperature unevenness in fixing device 30 is suppressed.

[0056] Second embodiment 8 is a front cross-sectional view of a heating device of the second embodiment. Fixing device 230, which is a heating device of the second embodiment, differs from the first embodiment in that it has guide ribs 81 formed on guide member 80. Explanation of the second embodiment in terms of the similarities to the first embodiment will be omitted.

[0057] The fixing device 230 includes a guide member 80 . Guide member 80 is integrally formed from a resin material or the like. Guide member 80 is disposed inside tubular film 35. Guide member 80 is fixed to stay 38. Guide member 80 has guide ribs 81.

[0058] The guide rib 81 is capable of contacting the inner surface of the tubular film 35. The guide rib 81 extends in the circumferential direction of the tubular film 35. The guide rib 81 is positioned near the film thermometer 64 in the circumferential direction of the tubular film 35. The film thermometer 64 is positioned away from the first downstream rib 71d downstream in the rotational direction R of the tubular film 35. The guide rib 81 extends from near the downstream side of the first downstream rib 71d to an area on the opposite side of the heater unit 40, across the stay 38. The guide rib 81 is positioned in most of the area in the circumferential direction of the tubular film 35 where the first upstream rib 71u and the first downstream rib 71d are not positioned.

[0059] In the present embodiment, the tubular film 35 has a base layer formed from a resin material such as polyimide (PI). The tubular film 35 does not have a metal layer. The tubular film 35, whose base layer is formed from a resin material, is easily deformed. This tubular film 35 may deform during rotation and become separated from the film thermometer 64. In this case, the accuracy of the film thermometer 64 in detecting the temperature of the tubular film 35 decreases. Guide rib 81, together with first upstream rib 71u and first downstream rib 71d, guides the rotation of tubular film 35. This reduces deformation of tubular film 35 during rotation, improving the accuracy with which film thermometer 64 detects the temperature of tubular film 35.

[0060] 9 is a perspective view of the support member and the guide member. The guide rib 81 is formed in a plate shape with the thickness direction being the y direction. A plurality of guide ribs 81 are arranged side by side in the y direction. The guide ribs 81 are arranged at positions different from the first upstream rib 71u and the first downstream rib 71d in the y direction. That is, the guide rib 81 and the first upstream rib 71u and the first downstream rib 71d have portions that do not overlap with each other in the y direction. It is desirable that the guide rib 81 and the first upstream rib 71u and the first downstream rib 71d do not have portions that overlap with each other in the y direction.

[0061] The position in the y direction where tubular film 35 abuts against guide rib 81 is different from the position in the y direction where tubular film 35 abuts against first upstream rib 71u and first downstream rib 71d. The temperature drop of tubular film 35 caused by the abutment with guide rib 81, first upstream rib 71u, and first downstream rib 71d is dispersed in the y direction. As a result, temperature unevenness in fixing device 30 is suppressed.

[0062] As described in detail above, fixing device 230 of the present embodiment has film thermometer 64 and guide rib 81. Film thermometer 64 measures the temperature of the inner surface of tubular film 35. Guide rib 81 is disposed near film thermometer 64 in the circumferential direction of tubular film 35. Guide rib 81 extends in the circumferential direction of tubular film 35 and is able to abut against the inner surface of tubular film 35. Guide rib 81 is disposed next to upstream rib 7u and downstream rib 7d in the y direction at a different position. As a result, temperature unevenness in the fixing device 30 is suppressed. The guide rib 81, the first upstream rib 71u and the first downstream rib 71d are desirably disposed at positions in the y direction different from the boundary portion 45s (see FIG. 7) between the multiple heat generating elements.

[0063] A first modified example of the second embodiment will be described. 10 is a bottom view of a guide member in a first modified example of the second embodiment. The first modified example of the second embodiment differs from the second embodiment in that it has a hole 87. A description of the first modified example that is the same as the second embodiment will be omitted.

[0064] The hole 87 penetrates the guide member 80 and the guide rib 81 along the radial direction of the tubular film 35. The hole 87 is formed at the same position in the y direction as the guide rib 81. The hole 87 is disposed at the end of the guide rib 81 in the +z direction. The hole 87 may be disposed at a position in the circumferential direction of the guide rib 81 different from that shown in FIG. 10. The number of holes 87 in the circumferential direction of the guide rib 81 is not limited to one and may be two or more. The hole 87 may be formed in only some of the multiple guide ribs 81, or may be formed in all of the guide ribs 81. The hole 87 may be formed in the first upstream rib 71u or the first downstream rib 71d.

[0065] Holes 87 reduce the contact area between guide ribs 81 and tubular film 35. This reduces the decrease in temperature of tubular film 35 due to contact with guide ribs 81. As a result, temperature unevenness in fixing device 30 is reduced.

[0066] A second modification of the second embodiment will be described. 11 is a bottom view of a guide member in a second modified example of the second embodiment. The second modified example of the second embodiment differs from the second embodiment in that it has a cutout portion 88. A description of the second modified example that is similar to the second embodiment will be omitted.

[0067] The cutout portion 88 is formed by cutting out a part of the outer periphery of the guide rib 81. The cutout portion 88 is disposed at an end of the guide rib 81 in the +z direction. The cutout portion 88 may be disposed at a position different from that shown in FIG. 11 in the circumferential direction of the guide rib 81. The number of cutout portions 88 in the circumferential direction of the guide rib 81 is not limited to one and may be two or more. The cutout portion 88 may be formed in only some of the multiple guide ribs 81, or may be formed in all of the guide ribs 81. The cutout portion 88 may be formed in the first upstream rib 71u or the first downstream rib 71d.

[0068] Cutouts 88 reduce the contact area between guide ribs 81 and tubular film 35. This reduces a decrease in temperature of tubular film 35 due to contact with guide ribs 81. As a result, temperature unevenness in fixing device 30 is reduced.

[0069] A third modification of the second embodiment will be described. 12 is a bottom view of a guide member in a third modified example of the second embodiment. The third modified example of the second embodiment differs from the second embodiment in that it has a curved surface portion 89. A description of the third modified example that is similar to the second embodiment will be omitted.

[0070] The curved surface portion 89 is formed such that the thickness of the guide rib 81 decreases continuously around the outer periphery of the guide rib 81. The curved surface portion 89 is formed on substantially the entire outer periphery of the guide rib 81. The curved surface portion 89 may be formed on a part of the outer periphery of the guide rib 81. The curved surface portion 89 has an arc shape in a cross section perpendicular to the circumferential direction of the guide rib 81. The radius of the arc is approximately half the thickness of the guide rib 81. The curved surface portion 89 is in line contact with the inner surface of the tubular film 35. The curved surface portion 89 may be formed on only some of the multiple guide ribs 81, or may be formed on all of the guide ribs 81. The curved surface portion 89 may be formed on the outer periphery of the first upstream rib 71u, or may be formed on the outer periphery of the first downstream rib 71d.

[0071] Curved surface portion 89 reduces the contact area between guide rib 81 and tubular film 35. This reduces a decrease in temperature of tubular film 35 due to contact with guide rib 81. As a result, temperature unevenness in fixing device 30 is reduced.

[0072] (Third embodiment) 13 is a front cross-sectional view of a heating device of the third embodiment. A fixing device 330, which is a heating device of the third embodiment, differs from the first embodiment in that it has a second upstream rib 72u as the upstream rib 7u and a second downstream rib 72d as the downstream rib 7d. A description of the third embodiment that is the same as the first embodiment will be omitted.

[0073] The second upstream rib 72u is formed on the +z direction surface of the upstream member 75u that fits along the inner surface of the tubular film 35. The second upstream rib 72u is capable of abutting against the inner surface of the tubular film 35. The second downstream rib 72d is formed on the +z direction surface of the downstream member 75d that fits along the inner surface of the tubular film 35. The second downstream rib 72d is capable of abutting against the inner surface of the tubular film 35.

[0074] 14 is a perspective view of the support member. The second downstream rib 72d extends in the circumferential direction of the tubular film 35. The width of the second downstream rib 72d in the y direction is approximately constant. The second downstream rib 72d is formed on approximately the entire downstream member 75d in the x direction. The height of the second downstream rib 72d in the z direction increases toward the +x direction. The second upstream rib 72u is formed in the same manner as the second downstream rib 72d. 15 is a bottom view of the support member. A plurality of second upstream ribs 72u are arranged in the y direction. A plurality of second downstream ribs 72d are arranged in the y direction.

[0075] The tubular film 35 abuts against the surfaces of the second upstream rib 72u and the second downstream rib 72d in the +z direction. The tubular film 35 is less likely to abut against the surfaces of the upstream member 75u and the downstream member 75d in the +z direction in the non-forming regions of the second upstream rib 72u and the second downstream rib 72d. This reduces the contact area between the tubular film 35 and the upstream member 75u and the downstream member 75d. This suppresses a decrease in temperature of the tubular film 35 due to contact with the upstream member 75u and the downstream member 75d. This reduces the time it takes for the heater unit 40 to heat the tubular film 35 to the fixing temperature. This reduces the time it takes for the image forming apparatus 1 to return from a print standby state to a printable state.

[0076] The second downstream rib 72d is disposed at a position different from the second upstream rib 72u in the y direction. That is, the second upstream rib 72u and the second downstream rib 72d have portions that do not overlap with each other in the y direction. It is preferable that the second upstream rib 72u and the second downstream rib 72d do not have portions that overlap with each other in the y direction.

[0077] The position in the y direction where the tubular film 35 abuts against the second upstream rib 72u is different from the position in the y direction where the tubular film 35 abuts against the second downstream rib 72d. The temperature drop of the tubular film 35 caused by the abutment between the second upstream rib 72u and the second downstream rib 72d is dispersed in the y direction. As a result, temperature unevenness in the fixing device 30 is suppressed.

[0078] The second downstream rib 72d is formed in an area including both ends in the y direction of the sheet S. Sheets S of various sizes enter the fixing device 330. The multiple second downstream ribs 72d are formed in an area including both ends in the y direction of the sheets S of various sizes. 13, the second downstream rib 72d supports the tubular film 35. The second downstream rib 72d positions the tubular film 35 close to the peeling plate 39 at both ends of the sheet S in the y direction. The corners of both ends of the sheet S in the y direction discharged from the nip N are less likely to get caught between the tubular film 35 and the peeling plate 39. This prevents the corners of the sheet S from folding or becoming clogged.

[0079] As described in detail above, the upstream rib 7u has the second upstream rib 72u formed on the surface of the upstream member 75u that fits along the inner surface of the tubular film 35. The downstream rib 7d has the second downstream rib 72d formed on the surface of the downstream member 75d that fits along the inner surface of the tubular film 35. Cylindrical film 35 abuts against second upstream rib 72u and second downstream rib 72d. This prevents a decrease in temperature of tubular film 35 due to contact with upstream member 75u and downstream member 75d. This reduces the time it takes image forming apparatus 1 to return from a print standby state to a printable state.

[0080] The second downstream rib 72d is formed in a region that includes both end portions of the sheet S in the y direction. The second downstream rib 72d positions the tubular film 35 close to the peeling plate 39 at both ends of the sheet S in the y direction. The corners of both ends of the sheet S in the y direction are less likely to get caught between the tubular film 35 and the peeling plate 39. This prevents the corners of the sheet S from folding or becoming clogged.

[0081] The fixing device 330 of the third embodiment has a second upstream rib 72u as the upstream rib 7u and a second downstream rib 72d as the downstream rib 7d. In contrast, the fixing device 330 may have the first upstream rib 71u of the first embodiment as the upstream rib 7u in addition to the second upstream rib 72u. The fixing device 330 may have the first downstream rib 71d of the first embodiment as the downstream rib 7d in addition to the second downstream rib 72d. It is preferable that the first upstream rib 71u, the first downstream rib 71d, the second upstream rib 72u and the second downstream rib 72d are arranged at different positions in the y direction.

[0082] In the third embodiment, it is desirable that the second upstream rib 72u and the second downstream rib 72d be disposed at positions in the y direction different from the boundaries 45s (see FIG. 7) between the multiple heat generating elements. The fixing device 330 of the third embodiment may have the guide rib 81 of the second embodiment. The guide rib 81, the second upstream rib 72u, and the second downstream rib 72d are desirably disposed at different positions in the y direction.

[0083] A first modified example of the third embodiment will be described. 16 is a bottom view of the support member in the first modified example of the third embodiment. The first modified example of the third embodiment differs from the third embodiment in that the second downstream rib 72d is inclined. The description of the first modified example that is the same as the third embodiment will be omitted.

[0084] The second downstream rib 72d extends at an incline so as to intersect with the x direction. The second downstream rib 72d inclines in the +y direction toward the +x direction. The width in the y direction of the second downstream rib 72d of the first modified example shown in FIG. 16 is equivalent to the width in the y direction of the second downstream rib 72d of the third embodiment shown in FIG. 15. That is, the contact area between the second downstream rib 72d of the first modified example and the tubular film 35 is equivalent to the contact area between the second downstream rib 72d of the third embodiment and the tubular film 35. This suppresses a decrease in temperature of the tubular film 35 due to contact with the second downstream rib 72d.

[0085] There are cases where the sheet S is discharged from the nip N in a state shifted in the y direction. Because the second downstream rib 72d is inclined, the width in the y direction of the tubular film 35 supported by the second downstream rib 72d increases. Even if the sheet S is discharged shifted in the y direction, the corners of the sheet S are less likely to get caught between the tubular film 35 and the peeling plate 39. This prevents the corners of the sheet S from folding or becoming clogged.

[0086] The image processing device of the embodiment is an image forming device 1, and the heating device is a fixing device 30, 230, 330. In contrast, the image processing device may be an erasing device, and the heating device may be an erasing unit. The erasing device performs a process of erasing (erasing) an image formed on a sheet with erasing toner. The erasing unit heats and erases the erasing toner image formed on the sheet passing through the nip.

[0087] According to at least one of the embodiments described above, the downstream rib 7d is disposed at a position different from the upstream rib 7u in the y direction, thereby suppressing temperature unevenness in the fixing device 30.

[0088] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0089] R...rotation direction, S...sheet, W...conveyance direction, y...longitudinal direction, 1...image forming apparatus (image processing apparatus), 7d...downstream rib, 7u...upstream rib, 30, 230, 330...fixing apparatus (heating apparatus), 35...cylindrical film (cylindrical body), 40...heater unit, 45...heating element set, 45a...central heating element (heating element), 45b1...first end heating element (heating element), 45b2...second end heating element (heating element), 45s...boundary portion, 64...film thermometer, 71d...first downstream rib, 71u...first upstream rib, 72d...second downstream rib, 72u...second upstream rib, 75d...downstream member, 75u...upstream member, 81...guide rib.

Claims

1. a rotation film having a length in a first direction and rotating about an axis parallel to the first direction; a first thermometer in contact with the inner surface of the rotating film; a second thermometer that contacts the inner surface of the rotating film near a center of the rotating film in the first direction and at a position offset from the center of the rotating film in the first direction; a heating element having a length in the first direction and a width in a second direction perpendicular to the first direction and coinciding with a rotation direction of the rotating film; a support member that holds the heating element in a fixed position relative to the rotating film; a stay that supports the support member, the first thermometer, and the second thermometer, extends in the first direction, and is surrounded by the rotating film. heating device.

2. the first thermometer is in contact with the inner surface of the rotating film downstream of the heating element in the rotation direction of the rotating film; The heating device according to claim 1 .

3. The support member faces the inner surface of the rotating film and has a curved portion that is in contact with the inner surface of the rotating film. The heating device according to claim 1 .

4. the second thermometer is in contact with the inner surface of the rotating film downstream of the heating element in the rotation direction of the rotating film; The heating device according to claim 1 .

5. the first thermometer and the second thermometer are in contact with the inner surface of the rotating film downstream of the heating element in the rotation direction of the rotating film; The heating device according to claim 1 .

Images