Heating device, nip forming device, and image forming device

Abstract

To prevent lubricant material from moving to an inner peripheral surface of a rotating body holding member.SOLUTION: A heating device comprises: a rotating body (fixing belt 21) that is held rotatably; a heat source (halogen heater 23) that heats an inner peripheral surface of the rotating body; rotating body holding members (flange members 40) that hold the inner peripheral surface on both ends in a longitudinal direction of the rotating body; and a liquid or semi-solid material that is adhered to the rotating body holding members and has lubricity. The rotating body holding members have holding parts (cylindrical parts 40a) that are in slide contact with the inner peripheral surface on both ends of the rotating body, and flange parts 40c that extend outward in a circumferential direction of the rotating body to sandwich both ends in the longitudinal direction of the rotating body. The rotating body holding members each have an inclined face 40d that is inclined in a direction going away from the inner peripheral surface of the opposing rotating body from the holding part toward the flange part.SELECTED DRAWING: Figure 4A

Description

Technical Field

[0001] The present invention relates to a heating device in which a rotating body is heated from the inside, a nip forming device using this heating device, and an image forming device.

Background Art

[0002] In image forming devices such as copiers, printers, facsimiles, or multifunction machines thereof, belt type or surf type fixing devices using thin rotating bodies are known (for example, Patent Document 1: JP-A-2005-592335). The rotating body is heated from the inside by a heat source such as a halogen heater. The inner peripheral surfaces at both longitudinal ends of the rotating body are slidably supported by a rotating body holding member (flange member).

[0003] A lubricating substance is interposed (adhered) between the rotating body holding member (flange member) and the rotating body to reduce frictional resistance and suppress the generation of abnormal noises. Here, the lubricating substance refers to a liquid or semi-solid substance having lubricity. When the rotating body holding member becomes hot, volatile substances generated from the heated lubricating substance may leak out as fine particles to the outside.

[0004] In recent years, from the perspective of environmental protection, it has been required to suppress not only the generation of volatile organic compounds but also the generation of fine particles. In particular, for fine particles having a diameter of 1 μm or less, the emission upper limit value is regulated in environmental standards such as the German Blue Angel.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Conventionally, a configuration has been adopted in which the lubricating substance between the rotating body holding member (flange member) and the rotating body is moved inward in the longitudinal direction so as not to leak to the outside. For example, in the fixing device of Patent Document 2 (JP-A-2007-72105), the lubricating substance is moved toward the longitudinal center by inclined grooves formed in the rotation guide portion (holding portion) of the flange member.

[0006] However, since there is a heating source such as a halogen heater inside the rotating body, the lubricating substance may be exposed to high temperatures when it moves towards the longitudinal center. Figure 6A shows the results of heating the lubricating substance on a hot plate and measuring the concentration of fine particles. From these measurements, it can be seen that fine particles begin to be emitted all at once when the temperature exceeds 200°C.

[0007] Figure 6A shows the temperature rise of silicone oil and fluorine grease used as lubricants, and the concentration of fine particles generated from these lubricants (1 cm³). 3 This is the result of a test that investigated the relationship with the number of FP / UFP generated per unit area. Here, "fine particles" refers to fine particles and ultrafine particles that can be measured using the measurement method and conditions in the following test, and the particle size is preferably in the range of 5.6 nm to 560 nm.

[0008] In this test, a liquid or semi-solid lubricating substance in a sample container was heated in a 1 cubic meter chamber (air exchange rate: 5 times) conforming to JIS A 1901. Sample container 1000 was made from a 50 mm × 50 mm × 5 mm aluminum plate with a φ22 mm, 2 mm deep recess 1000a, into which the sample was placed. The sample container 1000 was then placed on the hot plate of a heating device (AS ONE Clean Hot Plate MH-180CS, AS ONE Controller MH-3CS), and the sample was heated to a set temperature of 250°C. While monitoring the hot plate temperature, the FP / UFP number concentration in the chamber was measured using a measuring device (Fast Mobility Particle Sizer (TSI; Model 3091)) (Use Averaging Inneterval during Export: 30 seconds). Fluorine grease and silicone oil were used as lubricants, with a sample volume of 36 μl. In Figure 6A, the solid line shows the number concentration of FP / UFP generated from fluorine grease, and the dashed line shows the number concentration of FP / UFP generated from silicone oil. In Figure 6A, the horizontal axis shows the temperature of the hot plate; however, since the temperature rise of the hot plate and the temperature rise of the lubricant change almost synchronously, the temperature of the hot plate is considered to be the temperature of the lubricant here.

[0009] On the other hand, Figure 6B shows the results of measuring the number of microparticles [particles / second] generated when an image forming apparatus with a conventional fixing device was continuously printed for 10 minutes. Figure 6C shows the results of measuring the temperature of the inner and outer surfaces of the rotating body holding member (flange member) of the fixing device used. From Figure 6B, it can be seen that the number of microparticles increases sharply after about 3 minutes, and this timing almost coincides with the time when the inner surface of the flange in Figure 6C reached over 200°C. From this, it can be inferred that the inner surface of the flange is the location where microparticles are generated. The outer surface of the flange also reaches 200°C after about 9 minutes, but microparticles have already been generated before that.

[0010] Figures 7A and 7C illustrate the state in which the inner circumferential surface of the flange member 40 is heated by radiant heat from the halogen heater 23. Figure 7A shows the state in which radiant heat from the halogen heater 23 directly acts on the inner circumferential surface of the flange member 40. Figures 7B and 7C show the state in which the inner circumferential surface of the flange member 40 is heated even when a shielding plate is provided to block the radiant heat. As a result, as shown in Figure 7C, the lubricating substance (lightly shaded area) that has flowed onto the inner circumferential surface of the flange member 40 is heated and turned into fine particles.

[0011] Therefore, the objective of the present invention is to suppress the movement of lubricating substances to the inner circumferential surface of the rotating body holding member. [Means for solving the problem]

[0012] To solve the above problems, the present invention provides a heating device comprising a rotating body that is rotatably held, a heating source for heating the inner circumferential surface of the rotating body, a rotating body holding member for holding the inner circumferential surfaces of both longitudinal ends of the rotating body, and a liquid or semi-solid lubricating substance adhering to the rotating body holding member, wherein the rotating body holding member has a holding portion that slides against the inner circumferential surfaces of both ends of the rotating body, and a flange portion that extends outward in the circumferential direction of the rotating body so as to sandwich both longitudinal ends of the rotating body, and an inclined surface that slopes away from the opposing inner circumferential surface of the rotating body as it moves from the holding portion toward the flange portion. [Effects of the Invention]

[0013] According to the present invention, it is possible to suppress the movement of lubricating substances to the inner circumferential surface of the rotating body holding member. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. [Figure 2A] This is a cross-sectional view of the fixing device with the shielding member moved to the light-shielding position. [Figure 2B] This is a cross-sectional view of the fixing device with the shielding member moved to the retracted position. [Figure 3] It is a perspective view of a fixing device. [Figure 4A] It is a view of a flange member according to the first embodiment. [Figure 4B] It is a view of a flange member according to the second embodiment. [Figure 4C] It is a view of a flange member according to the third embodiment. [Figure 4D] It is a view of a flange member according to the fourth embodiment. [Figure 4E] It is a view of a flange member according to the fifth embodiment. [Figure 5A] It is a correlation graph of the wall thickness of the flange member and the temperature of the outer peripheral surface of the flange. [Figure 5B] It is a cross-sectional view of the flange member used for temperature measurement. [Figure 5C] It is a correlation graph of the driving time of the fixing device and the temperatures of the inner and outer peripheral surfaces of the flange member. [Figure 5D] It is a correlation graph of the driving time of the fixing device according to the present embodiment and the generation rate of fine particles. [Figure 6A] It is a correlation graph of the temperature of the hot plate and the fine particle concentration. [Figure 6B] It is a correlation graph of the driving time of a conventional fixing device and the generation rate of fine particles. [Figure 6C] It is a correlation graph of the driving time of a conventional fixing device and the temperatures of the inner and outer peripheral surfaces of the flange. [Figure 7A] It is a cross-sectional view of a conventional fixing device. [Figure 7B] It is a cross-sectional view of a conventional fixing device. [Figure 7C] It is a cross-sectional view of a conventional fixing device. [Figure 8] It is a view showing one form of an inkjet type image forming apparatus provided with a drying device. [Figure 9] It is a view showing an example of a drying device. [Figure 10] It is a view showing one form of an image forming apparatus provided with a laminating device.

Embodiments for Carrying Out the Invention

[0015] Embodiments of the present invention will be described below with reference to the attached drawings. In each drawing illustrating the embodiments of the present invention, components such as members and parts having the same function or shape will be given the same reference numerals to the extent possible so that they can be identified, and their description will be omitted after they have been described once.

[0016] (●Image forming apparatus) The schematic configuration and operation of an image forming apparatus using a fixing device according to an embodiment of the present invention will be described with reference to Figure 1, and then the details of the fixing device will be described.

[0017] The image forming apparatus 1 shown in Figure 1 is a color laser printer. Four image forming units 4Y, 4M, 4C, and 4K are located in the center of the apparatus body. Each image forming unit 4Y, 4M, 4C, and 4K has the same configuration except that it contains different colored developers corresponding to the color separation components of a color image: yellow (Y), magenta (M), cyan (C), and black (K).

[0018] Specifically, each image unit 4Y, 4M, 4C, and 4K includes a drum-shaped photoreceptor 5 as a latent image carrier, a charging device 6 for charging the surface of the photoreceptor 5, a developing device 7 for supplying toner to the surface of the photoreceptor 5, and a cleaning device 8 for cleaning the surface of the photoreceptor 5. In Figure 1, only the photoreceptor 5, charging device 6, developing device 7, and cleaning device 8 of the black image unit 4K are labeled with reference numerals, while reference numerals are omitted for the other image units 4Y, 4M, and 4C.

[0019] Below each image-forming section 4Y, 4M, 4C, and 4K, an exposure device 9 is provided to expose the surface of the photoreceptor 5. The exposure device 9 includes a light source, a polygon mirror, an f-θ lens, a reflective mirror, etc., and is configured to irradiate the surface of each photoreceptor 5 with laser light based on the image data.

[0020] A transfer device 3 is positioned above each image-forming section 4Y, 4M, 4C, and 4K. The transfer device 3 comprises an intermediate transfer belt 30 as an intermediate transfer body and four primary transfer rollers 31 as primary transfer means.

[0021] The transfer device 3 also includes a secondary transfer roller 36 as a secondary transfer means and a secondary transfer backup roller 32. The transfer device 3 also includes a cleaning backup roller 33, a tension roller 34, and a belt cleaning device 35.

[0022] The intermediate transfer belt 30 is an endless belt and is stretched by a secondary transfer backup roller 32, a cleaning backup roller 33, and a tension roller 34. Here, the rotational drive of the secondary transfer backup roller 32 causes the intermediate transfer belt 30 to travel (rotate) in the direction indicated by the arrow in Figure 1.

[0023] Each of the four primary transfer rollers 31 forms a primary transfer nip by sandwiching the intermediate transfer belt 30 between itself and each photoreceptor 5. A power supply (not shown) is connected to each primary transfer roller 31, and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to each primary transfer roller 31.

[0024] The secondary transfer roller 36 sandwiches the intermediate transfer belt 30 between itself and the secondary transfer backup roller 32 to form a secondary transfer nip. The secondary transfer roller 36 is also connected to a power supply (not shown) similar to the primary transfer roller 31, and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the secondary transfer roller 36.

[0025] The belt cleaning device 35 has a cleaning brush and a cleaning blade that are positioned to contact the intermediate transfer belt 30. A waste toner transfer hose (not shown) extending from this belt cleaning device 35 is connected to the inlet of a waste toner container (not shown).

[0026] The top of the printer body is provided with a bottle storage section 2, and four toner bottles 2Y, 2M, 2C, and 2K for storing replenishment toner are detachably mounted in the bottle storage section 2. A supply path (not shown) is provided between each toner bottle 2Y, 2M, 2C, and 2K and each of the developer units 7, and toner is supplied from each toner bottle 2Y, 2M, 2C, and 2K to each of the developer units 7 via this supply path.

[0027] On the other hand, the lower part of the printer body is equipped with a paper feed tray 10 that houses the paper P used as a recording medium, and a paper feed roller 11 that ejects the paper P from the paper feed tray 10. The recording medium includes not only plain paper, but also cardboard, postcards, envelopes, thin paper, coated paper (such as coated paper and art paper), tracing paper, and OHP sheets. Although not shown in the diagram, a manual paper feed mechanism may also be provided.

[0028] Inside the printer body, there is a transport path R for transporting paper P from the paper feed tray 10 through a secondary transfer nip and out of the device. In the transport path R, upstream of the secondary transfer roller 36 in the paper transport direction, there is a pair of timing rollers 12 which are used as timing rollers to transport the paper P to the secondary transfer nip at the appropriate timing.

[0029] Downstream from the secondary transfer roller 36 in the paper transport direction, a fixing device 20 is provided for fixing the unfixed image transferred to the paper P. Furthermore, downstream from the fixing device 20 in the paper transport direction of the transport path R, a pair of paper discharge rollers 13 are provided for discharging the paper outside the device. On the top surface of the printer body, a paper discharge tray 14 is provided for storing the paper discharged outside the device.

[0030] Next, the basic operation of the printer according to this embodiment will be described with reference to Figure 1. When the image formation operation is started, each photoreceptor 5 in each image formation section 4Y, 4M, 4C, and 4K is rotated clockwise in the figure by a drive device (not shown), and the surface of each photoreceptor 5 is uniformly charged to a predetermined polarity by a charging device 6.

[0031] Laser light from the exposure device 9 is shone onto the surface of each charged photoreceptor 5, forming an electrostatic latent image on the surface of each photoreceptor 5. At this time, the image information exposed to each photoreceptor 5 is monochrome image information obtained by decomposing a desired full-color image into yellow, magenta, cyan, and black color information. When toner is supplied to the electrostatic latent image formed on each photoreceptor 5 by each developing device 7, the electrostatic latent image is manifested (made visible) as a toner image.

[0032] When the image formation operation begins, the secondary transfer backup roller 32 rotates counterclockwise in the figure, causing the intermediate transfer belt 30 to move in a circular motion in the direction indicated by the arrow in the figure. A constant voltage or constant current controlled voltage with the opposite polarity to the charge polarity of the toner is applied to each primary transfer roller 31, thereby forming a transfer electric field at the primary transfer nip between each primary transfer roller 31 and each photoreceptor 5.

[0033] Subsequently, as each photoreceptor 5 rotates, when the toner images of each color on the photoreceptor 5 reach the primary transfer nip, the toner images on each photoreceptor 5 are sequentially superimposed and transferred onto the intermediate transfer belt 30 by the transfer electric field formed at the primary transfer nip. Thus, a full-color toner image is carried on the surface of the intermediate transfer belt 30.

[0034] Any toner on each photoreceptor 5 that could not be transferred to the intermediate transfer belt 30 is removed by the cleaning device 8. Then, the surface of each photoreceptor 5 is discharged by a static eliminator (not shown), and its surface potential is reset.

[0035] At the bottom of the printer, the paper feed roller 11 starts rotating, and the paper P is fed from the paper feed tray 10 into the transport path R. Once the paper P is fed into the transport path R, its transport is temporarily stopped by the timing roller pair 12.

[0036] Subsequently, the rotational drive of the timing roller pair 12 is started at a predetermined timing, and the paper P is transported to the secondary transfer nip in accordance with the timing when the toner image on the intermediate transfer belt 30 reaches the secondary transfer nip. At this time, a transfer voltage with the opposite polarity to the toner charge polarity of the toner image on the intermediate transfer belt 30 is applied to the secondary transfer roller 36, thereby forming a transfer electric field at the secondary transfer nip.

[0037] Then, this transfer electric field transfers the toner image on the intermediate transfer belt 30 onto the paper P all at once. Any remaining toner on the intermediate transfer belt 30 that was not transferred to the paper P is removed by the belt cleaning device 35, and the removed toner is transported to a waste toner container (not shown) for collection.

[0038] Subsequently, the paper P is transported to the fuser unit 20, where the fuser unit 20 fixes the toner image on the paper P. Then, the paper P is ejected from the device by the paper output roller 13 and stored on the paper output tray 14.

[0039] The above description concerns the image formation process when forming a full-color image on paper. However, it is also possible to form a monochrome image using one of the four image formation units (4Y, 4M, 4C, 4K), or to form a two-color or three-color image using two or three image formation units.

[0040] (● Fixing device) Figures 2A and 2B are cross-sectional views of the fixing device 20 of this embodiment, which is an example of a nip forming apparatus. The fixing device 20 has a fixing belt 21 as a rotating body and a pressure roller 22 as an opposing member that abuts the outer circumferential surface of the fixing belt 21.

[0041] The fixing device 20 also includes a halogen heater 23 as a heat source for heating the fixing belt 21, and a nip-forming member 24 that contacts the pressure roller 22 from the inner circumference of the fixing belt 21 to form a nip portion N. The fixing device 20 also includes a stay 25 that supports the nip-forming member 24, and a reflecting member 26 that reflects radiant heat from the halogen heater 23 back onto the fixing belt 21. The fixing device 20 also includes a shielding member 27 that shields against radiant heat from the halogen heater 23, and a temperature sensor 28 as a temperature detection means for detecting the temperature of the fixing belt 21.

[0042] The fixing belt 21 described above is composed of a thin-walled, flexible, endless belt member (including a film). More specifically, the fixing belt 21 has an inner circumferential base material made of a metal material such as nickel or SUS, or a resin material such as polyimide (PI).

[0043] Furthermore, it includes a release layer on the outer periphery formed of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or polytetrafluoroethylene (PTFE). Additionally, an elastic layer made of a rubber material such as silicone rubber, foamed silicone rubber, or fluororubber may be interposed between the substrate and the release layer.

[0044] Furthermore, while the absence of an elastic layer reduces heat capacity and improves fixation, when the unfixed toner is compressed and fixed, minute irregularities on the belt surface may be transferred to the image, potentially causing uneven gloss in solid areas of the image. To prevent this, it is desirable to provide an elastic layer with a thickness of 80 μm or more. By providing an elastic layer with a thickness of 80 μm or more, minute irregularities can be absorbed by the elastic deformation of the elastic layer, thus avoiding the occurrence of uneven gloss.

[0045] In this embodiment, in order to reduce the heat capacity of the fixing belt 21, the fixing belt 21 is made thinner and smaller in diameter. Specifically, the thicknesses of the base material, elastic layer, and release layer that make up the fixing belt 21 are set to the ranges of 20-50 μm, 80-300 μm, and 3-50 μm, respectively, and the overall thickness is set to 1 mm or less.

[0046] Furthermore, the diameter of the fixing belt 21 is set to 20-40 mm. To further reduce the heat capacity, it is preferable to make the overall thickness of the fixing belt 21 0.2 mm or less, and even more preferably 0.16 mm or less. Also, it is preferable to make the diameter of the fixing belt 21 30 mm or less.

[0047] The pressure roller 22 described above is composed of a core metal 22a, an elastic layer 22b made of foamed silicone rubber, silicone rubber, or fluororubber, etc., provided on the surface of the core metal 22a, and a release layer 22c made of PFA or PTFE, etc., provided on the surface of the elastic layer 22b. The pressure roller 22 is pressed toward the fixing belt 21 by a pressing means (not shown), such as a spring, and contacts the nip forming member 24 via the fixing belt 21. At the point where the pressure roller 22 and the fixing belt 21 are in contact, the elastic layer 22b of the pressure roller 22 is crushed, forming a nip portion N of a predetermined width.

[0048] The pressure roller 22 is configured to be rotationally driven by a drive source such as a motor (not shown) provided in the printer body. When the pressure roller 22 is rotationally driven, the driving force is transmitted to the fixing belt 21 at the nip section N, causing the fixing belt 21 to rotate in response. Except for the nip section N, flange members 40, which serve as rotating body holding members, are inserted at both ends of the fixing belt 21, as will be described later in Figure 3, and the fixing belt 21 is held and rotated by these flange members 40.

[0049] In this embodiment, the pressure roller 22 is a solid roller, but it may also be a hollow roller. In that case, a heating source such as a halogen heater may be placed inside the pressure roller 22.

[0050] Furthermore, while the elastic layer 22b may be made of solid rubber, if there is no heat source inside the pressure roller 22, sponge rubber may be used. Sponge rubber is preferable because it has better heat insulation properties, which reduces heat loss from the fixing belt 21.

[0051] The halogen heater 23 is positioned on the inner circumference side of the fixing belt 21 and on the upstream side of the nip section N in the paper transport direction. More specifically, in Figure 2A, if we consider L to be a virtual line passing through the center Q of the nip section N in the paper transport direction and the rotation center O of the pressure roller 22, the halogen heater 23 is positioned upstream of this virtual line L in the paper transport direction (below Figure 2A).

[0052] The halogen heater 23 is configured to generate heat under the output control of a power supply unit located in the printer body. The output control of the power supply unit is performed based on the detection result of the surface temperature of the fuser belt 21 by the temperature sensor 28.

[0053] By controlling the output of the halogen heater 23 in this way, the temperature of the fixing belt 21 (fixing temperature) can be set to a desired temperature. Alternatively, instead of a temperature sensor that detects the temperature of the fixing belt 21, a temperature sensor (not shown) that detects the temperature of the pressure roller 22 may be provided, and the temperature of the fixing belt 21 may be predicted based on the temperature detected by that temperature sensor.

[0054] In this embodiment, two halogen heaters 23 are provided, but the number of halogen heaters 23 may be one or three or more depending on the size of the paper used in the printer. However, considering the cost of the halogen heaters 23 themselves and the space on the inner circumference of the fixing belt 21, it is desirable to have two or fewer halogen heaters 23. The heat source for heating the fixing belt 21 is heated by radiant heat, and in addition to halogen heaters, resistance heating elements or carbon heaters can also be used.

[0055] The nip-forming member 24 has a base pad 24a and a low-friction sliding sheet 24b provided on the surface of the base pad 24a facing the fixing belt 21. The base pad 24a is arranged longitudinally along the axial direction of the fixing belt 21 or the axial direction of the pressure roller 22.

[0056] The shape of the nip portion N is determined by the pressure applied to the base pad 24a by the pressure roller 22. In this embodiment, the shape of the nip portion N is flat, but it may be concave or have other shapes.

[0057] The sliding sheet 24b is provided to reduce sliding friction when the fixing belt 21 rotates. However, if the base pad 24a itself is made of a low-friction material, a configuration without the sliding sheet 24b is also possible.

[0058] The base pad 24a is made of a heat-resistant material with a heat resistance temperature of 200°C or higher, preventing deformation of the nip-forming member 24 due to heat in the toner fixing temperature range, ensuring a stable state of the nip portion N, and stabilizing the output image quality. As the material for the base pad 24a, general heat-resistant resins such as polyethersulfone (PES), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyethernitrile (PEN), polyamide-imide (PAI), and polyetheretherketone (PEEK) can be used.

[0059] The base pad 24a is fixedly supported by the stay 25. This prevents the nip forming member 24 from bending due to the pressure from the pressure roller 22, and ensures that a uniform nip width is obtained along the axial direction of the pressure roller 22.

[0060] The stay 25 is preferably made of a metal material with high mechanical strength, such as stainless steel or iron, in order to satisfy the function of preventing deflection of the nip forming member 24. The base pad 24a is also preferably made of a material that is somewhat hard in order to ensure strength. As the material of the base pad 24a, resins such as liquid crystal polymer (LCP), metals, or ceramics can be applied.

[0061] The reflective member 26 is fixedly supported on the stay 25 so as to face the halogen heater 23. By reflecting the radiant heat (or light) emitted from the halogen heater 23 onto the fixing belt 21, the reflective member 26 suppresses the transfer of heat to the stay 25, etc., thereby efficiently heating the fixing belt 21 and saving energy.

[0062] Aluminum or stainless steel can be used as the material for the reflective member 26. In particular, if an aluminum base material coated with silver, which has low emissivity (high reflectivity), is used, it is possible to improve the heating efficiency of the fixing belt 21.

[0063] The surface of the reflective member 26 facing the halogen heater 23 is formed to widen toward the inner circumferential surface of the fixing belt 21. In the reflective member 26 shown in Figure 2A, the portion facing the halogen heater 23 below (the portion extending along the circumferential direction of the fixing belt 21) is provided to shield against radiant heat at both ends of the halogen heater 23. This portion is not provided along the entire longitudinal direction of the reflective member 26.

[0064] The shielding member 27 is constructed by forming a heat-resistant metal plate, such as stainless steel (SUS), with a thickness of 0.1 mm to 1.0 mm, into a cross-sectional shape that conforms to the inner circumferential surface of the fixing belt 21. In the illustrated example, the shielding member 27 has an ended cross-sectional shape, rather than a closed annular shape in the circumferential direction. Specifically, the shielding member 27 has a partially arc-shaped cross-section.

[0065] The shielding member 27 is rotatable around the halogen heater 23, and in this embodiment, it is rotatable along the circumferential direction of the fixing belt 21. Specifically, in the circumferential region of the fixing belt 21, there is a direct heating region where the halogen heater 23 directly heats the fixing belt 21 in direct contact with it. There is also a non-direct heating region where other members (such as the reflective member 26, stay 25, nip forming member 24, etc.) other than the shielding member 27 are interposed between the halogen heater 23 and the fixing belt 21.

[0066] If it is necessary to heat shield the space between the halogen heater 23 and the fixing belt 21, the shielding member 27 is positioned at the shielding location on the direct heating side, as shown in Figure 2A. If it is not necessary to heat shield the space between the halogen heater 23 and the fixing belt 21, the shielding member 27 is moved to the retracted position on the non-direct heating side, as shown in Figure 2B.

[0067] In other words, the shielding member 27 is moved to the back side of the reflective member 26 and the stay 25. Furthermore, since the shielding member 27 requires heat resistance, it is preferable to use a metal material such as aluminum, iron, or stainless steel, or a ceramic material for its material.

[0068] Figure 3 is a perspective view of the fixing device 20 of this embodiment. As shown in Figure 3, flange members 40, which serve as rotating body holding members, are inserted into both ends of the fixing belt 21.

[0069] The fixing belt 21 is held rotatably by the sliding contact of its inner circumferential surfaces at both longitudinal ends with the flange members 40. Each flange member 40, halogen heater 23, and stay 25 are fixedly supported by a pair of side plates (not shown) of the fixing device 20. The cylindrical portion of the flange member 40 on the pressure roller 22 side has a notch 40m formed to prevent interference with the pressure roller 22. Therefore, the cylindrical portion of the flange member 40 has a C-shape.

[0070] (●Operation of the fixing device) The operation of the fuser device 20 according to this embodiment will be described below with reference to Figures 2A and 2B. When the power switch of the printer body is turned on, power is supplied to the halogen heater 23, and the pressure roller 22 starts rotating clockwise in Figures 2A and 2B. As a result, the fuser belt 21 rotates counterclockwise in Figures 2A and 2B due to the frictional force with the pressure roller 22.

[0071] Subsequently, the paper P on which the unfixed toner image T is carried by the image forming process described above is guided by a guide plate (not shown) and transported in the direction of arrow A1 in Figure 2A, and fed into the nip portion N of the fixing belt 21 and pressure roller 22, which are in a press-fit state. Then, the heat from the fixing belt 21 heated by the halogen heater 23 and the pressure between the fixing belt 21 and the pressure roller 22 fix the toner image T to the surface of the paper P.

[0072] The paper P on which the toner image T has been fixed is discharged from the nip section N in the direction of arrow A2 in Figure 2A. At this time, the leading edge of the paper P comes into contact with the tip of a separating member (not shown), and the paper P is separated from the fixing belt 21. Subsequently, the separated paper P is discharged outside the machine by the paper output roller as described above and stored in the paper output tray.

[0073] [●Flange component of heating device] The heating device of this embodiment is comprised of the aforementioned fixing belt 21, halogen heater 23, and flange member 40. The flange member 40 can be made of a heat-resistant resin such as liquid crystal polymer, and the following first to fifth embodiments are possible. These embodiments are illustrative, and it goes without saying that the present invention is not limited to these embodiments.

[0074] (●First embodiment) Figures 4A(a) and 4A(b) are horizontal cross-sectional plan views of the flange member 40 and the anchoring belt 21. As shown in Figure 4A(a), the flange member 40 has a cylindrical portion 40a that serves as a retaining portion that slides against the inner circumferential surfaces of both ends of the anchoring belt 21, an inner circumferential surface 40b of the cylindrical portion 40a, and a flange portion 40c that is located at the outer end in the longitudinal direction and extends outward in the circumferential direction of the anchoring belt 21 (perpendicular to the longitudinal direction) so as to sandwich both ends of the anchoring belt 21 in the longitudinal direction.

[0075] The flange portion 40c is formed perpendicularly in an almost L-shape, with respect to the longitudinal direction of the flange member 40. The L-shape can be either vertically or horizontally elongated. A lubricating substance LA is attached to the cylindrical portion 40a of the flange member 40 to facilitate the sliding of the anchoring belt 21.

[0076] Between the cylindrical portion 40a and the flange portion 40c, an inclined surface 40d is formed that slopes away from the inner circumferential surface of the opposing anchoring belt 21 as it moves from the cylindrical portion 40a towards the flange portion 40c. That is, the inclined surface 40d is formed such that its outer diameter decreases as it moves outward in the longitudinal direction. This inclined surface 40d forms a space for accumulating the lubricating substance LA (lubricating substance reservoir). Here, the lubricating substance LA includes liquid, semi-solid, or a mixture thereof. "Liquid" refers to a colloidal sol in which a solid is contained in a liquid, and "semi-solid" refers to a gel in which the sol has solidified into a jelly-like state.

[0077] The inclination angle θ of the inclined surface 40d with respect to the longitudinal direction can be set, for example, in the range of 3 to 8°. The inclined surface 40d can be composed of a conical surface formed from the longitudinal outer end of the cylindrical portion 40a toward the flange portion 40c.

[0078] The longitudinal length of the inclined surface 40d can be set to, for example, around 8 mm. Furthermore, the deepest point of the inclined surface 40d can be set to be lower by, for example, 0.5 to 1 mm relative to the cylindrical portion 40a.

[0079] The wall thickness to the deepest point, relative to the inner circumferential surface 40b, can be set in the range of, for example, 1 to 1.5 mm. According to the temperature measurement results in Figure 5A, which will be described later, by setting the wall thickness to 1.1 mm or more, the temperature rise at the deepest point can be suppressed to 200°C or less.

[0080] As shown in Figure 4A(b), a circumferential annular groove 40e can be formed between the deepest part of the inclined surface 40d and the base of the flange portion 40c. This annular groove 40e can increase the space for accumulating the lubricating substance LA (lubricating substance reservoir). By making the wall thickness from the inner circumferential surface 40b to the bottom of the annular groove 40e 1.1 mm or more, the temperature rise at the bottom can be suppressed to 200°C or less.

[0081] (●Second embodiment) Figures 4B(a) and 4B(b) show that the inclined surface 40d in Figures 4A(a) and 4B(b) is composed of multiple inclined grooves 40f formed in the longitudinal direction of the surface of the cylindrical portion 40a. Multiple inclined grooves 40f are formed at equal intervals in the circumferential direction of the cylindrical portion 40a.

[0082] The longitudinal outer end of the inclined groove 40f is continuous with the base of the flange portion 40c in Figure 4B(a) and with the annular groove 40g in Figure 4B(b). Between the inclined grooves 40f, the outer ends of the cylindrical portions 40a extend continuously in a comb-like pattern.

[0083] (●Third embodiment) Figures 4C(a) and 4C(b) show that the inclined groove 40f in Figures 4B(a) and 4C(b) is inclined toward the inner surface of the flange portion 40c in the direction of rotation of the fixing belt 21 (arrow direction) to form a helical inclined groove 40h. The inclination angle of the helical inclined groove 40h in the direction of the arrow can be set, for example, within the range of 1° to 70°. Multiple helical inclined grooves 40h are formed at equal intervals in the circumferential direction of the cylindrical portion 40a.

[0084] The longitudinal outer end of the helical inclined groove 40h is continuous with the base of the flange portion 40c in Figure 4C(a) and with the annular groove 40i in Figure 4C(b). Between the helical inclined grooves 40h, the outer ends of the cylindrical portions 40a extend continuously in a comb-like pattern.

[0085] (●Fourth embodiment) Figure 4D shows that a circumferential annular groove 40k is formed on the longitudinal inner side of the cylindrical portion 40a (first cylindrical portion 40a) in Figure 4A(a), and a second cylindrical portion 40j is formed further longitudinally inward of the annular groove 40k. This second cylindrical portion 40j is formed with a smaller diameter than the first cylindrical portion 40a so that it is in close proximity to the inner circumferential surface of the anchoring belt 21 without contact.

[0086] A first lubricating substance reservoir is formed by the inclined surface 40d, and a second lubricating substance reservoir is formed by the annular groove 40k. By configuring two stages of lubricating substance reservoirs in this way, leakage of the lubricating substance LA can be made even more difficult than in Figure 4A(a).

[0087] (●Fifth embodiment) The flange member 40 in Figure 4E has a first cylindrical portion 40a that slides against the inner circumferential surfaces of both ends of the anchoring belt 21, an inner circumferential surface 40b of the first cylindrical portion 40a, and a flange portion 40c that is located at the outer end in the longitudinal direction and extends radially outward (perpendicular to the axis) so as to sandwich both ends of the anchoring belt 21 in the longitudinal direction.

[0088] A circumferential annular groove 40k is formed on the longitudinal inner side of the first cylindrical portion 40a, and a second cylindrical portion 40j is formed further longitudinally inward of the annular groove 40k. This second cylindrical portion 40j is formed with a smaller diameter than the first cylindrical portion 40a so that it is in close proximity to the inner circumferential surface of the anchoring belt 21 without contact. A lubricating substance reservoir is formed by the annular groove 40k.

[0089] The fifth embodiment in Figure 4E can be described as the fourth embodiment in Figure 4D with the inclined surface 40d omitted. Since the first lubricating substance reservoir is formed by the annular groove 40k, the inclined surface 40d can be omitted.

[0090] (●Verification) Based on Figures 5A-5D, we will verify whether the generation of fine particles and ultrafine particles was suppressed. Figure 5A is a correlation graph between the wall thickness of the flange member 40 and the outer surface temperature. From this correlation graph, it can be seen that the wall thickness needs to be 1.1 mm or more in order to keep the outer surface temperature below 200°C.

[0091] Figure 5B shows the flange member 40 of the first embodiment (Figure 4A(b)) used for temperature measurement in Figure 5A. The material of the flange member 40 is a heat-resistant resin such as liquid crystal polymer. Since the bottom of the annular groove 40e is the thinnest, the wall thickness of this bottom was set to 1.1 mm.

[0092] Figure 5C is a graph showing the temperatures of the outer and inner surfaces of the flange member 40, similar to Figure 6C. As can be seen from the graph in Figure 5C, the inner surface temperature of the flange member 40 exceeds 200°C after 200 seconds of continuous printing, but the outer surface temperature does not exceed 200°C even after 600 seconds of continuous printing.

[0093] Figure 5D is a graph showing the generation rate (pieces / second) of fine particles (FP) and ultrafine particles (UFP) after performing a continuous print of sufficient length according to a measurement method compliant with the German environmental label "Blue Angel Mark". The generation concentration of FP / UFP was measured using a particle detector FMPS (Model 3091 Fast Mobility Sizer, manufactured by Tokyo Direc Co., Ltd.).

[0094] As lubricants, fluorine grease (70 mg) and silicone oil (35 mg) were used. This graph confirms that FP / UFP generation was minimal.

[0095] The standard value for the "Blue Angel Mark" is 3.5 × 10^11, and the measurement result in Figure 5D is significantly below this standard value. This is due to the fact that the leakage of the lubricating substance LA to the inner circumferential surface 40b of the flange member 40 was almost eliminated, and the temperature of the cylindrical portion 40a, inclined surface 40d, and annular groove 40e on the outer circumferential surface of the flange member 40 was suppressed to below 200°C.

[0096] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the image forming apparatus is not limited to a printer as shown in Figure 1, but can be a copier, a facsimile, or a combination device thereof. Furthermore, the present invention is not limited to cases where it is applied to a fixing device mounted on an electrophotographic image forming apparatus as described above. For example, the present invention can also be applied to heating devices other than fixing devices, such as a drying device mounted on an inkjet image forming apparatus that dries liquids such as ink applied to paper.

[0097] Figure 8 shows one configuration of an inkjet image forming apparatus equipped with a drying device. The inkjet image forming apparatus 2000 shown in Figure 8 comprises an image reading device 202, an image forming unit 203, a sheet supply device 204, a drying device 206, and a sheet discharge unit 207. A sheet alignment device 3000 is also positioned next to the inkjet image forming apparatus 2000.

[0098] In this inkjet image forming apparatus 2000, when an instruction to start printing is given, a sheet such as paper to be used as a recording medium is fed from the sheet supply device 204. When the sheet is transported to the image forming unit 203, ink is ejected from the liquid ejection head 214 of the image forming unit 203 onto the sheet based on the image information of the original document read by the image reading device 202 or the print information instructed to print from a terminal, and an image is formed on the sheet.

[0099] The sheet on which the image has been formed is selectively guided to either a transport path 222 that passes through the drying device 206 or a transport path 223 that does not pass through the drying device 206. If the sheet is guided to the drying device 206, the drying device 206 accelerates the drying of the ink on the sheet, and the sheet is then guided to either the sheet discharge unit 207 or the sheet alignment device 3000. On the other hand, if the sheet is guided to the transport path 223 that does not pass through the drying device 206, the sheet is then guided directly to either the sheet discharge unit 207 or the sheet alignment device 3000. If the sheet is guided to the sheet alignment device 3000, the sheet is aligned and placed.

[0100] As shown in Figure 9, the drying apparatus 206 comprises a heating belt 291 as a first rotating body, a heating roller 292 as a second rotating body, a first heater 293 as a heat source for heating the heating belt 291, a second heater 294 as a heat source for heating the heating roller 292, a nip forming member 295, a stay 296 as a support member, a reflector member 297, and a belt holding member 298 as a rotating body holding member that rotatably holds the heating belt 291.

[0101] The nip-forming member 295 contacts the outer surface of the heating roller 292 via the heating belt 291, forming a nip portion N between the heating belt 291 and the heating roller 292. As shown in Figure 9, when the sheet 250 carrying the image (ink I) is conveyed to the nip portion N of the drying device 206, the sheet 250 is heated while being conveyed by the heating belt 291 and heating roller 292, which rotate in the direction of the arrow in the figure. This promotes the drying of the ink I on the sheet 250.

[0102] In the drying apparatus 206 shown in Figure 9, the heating belt 291 is rotatably held by a pair of belt retaining members 298 located at both ends in its longitudinal direction. Therefore, when the heating belt 291 is heated and the temperature of the belt retaining members 298 rises, there is a risk that FP / UFP may be generated from the lubricating substance adhering to the belt retaining members 298. Accordingly, even in such a drying apparatus 206, by applying the present invention, the temperature rise of the belt retaining members 298 can be suppressed, and the generation of FP / UFP can be effectively suppressed.

[0103] Furthermore, the present invention is also applicable to an image forming apparatus equipped with a laminating apparatus as shown in Figure 10. The image forming apparatus 4000 shown in Figure 10 includes, in addition to the laminating apparatus 401, an image forming unit 402 having a plurality of image forming units 411C, 411M, 411Y, 411Bk, an exposure apparatus 412, and a transfer apparatus 413, a fixing apparatus 403, and a paper feeding unit 404 as a recording medium supply unit.

[0104] The laminating apparatus 401 is a heating device that heats and pressurizes two sheets of paper with the paper inserted between them to heat-press the sheets onto the paper. Specifically, the laminating apparatus 401 includes a sheet supply unit 420 that supplies the sheets 450, a sheet peeling unit 430 that separates the sheets supplied from the sheet supply unit 420 into two sheets, and a heat-pressure roller 440 as a rotating body that conveys the paper and sheets while heating and pressurizing them with the paper inserted between the two separated sheets. The heat-pressure roller 440 is pressurized by a heating source such as a heater, and both ends in the longitudinal direction are rotatably held by a pair of rotating body holding members such as bearings.

[0105] In the image forming apparatus 4000 shown in Figure 10, when paper P, which serves as a recording medium, is supplied from the paper feeding unit 404 to the image forming unit 402, an image is formed in the image forming unit 402 and transferred to the supplied paper P. The paper P with the transferred image is then transported to the fixing unit 403, where the image is fixed. Note that the image forming operation and transfer operation in the image forming unit 402 (the operation of each image forming unit 411C, 411M, 411Y, 411Bk, the exposure unit 412, and the transfer unit 413), and the fixing operation in the fixing unit 403 are basically the same as those in the above embodiment, so their explanation is omitted.

[0106] The paper P, after being fixed, is then transported to the laminating device 401 and inserted between the two separated sheets. The paper P is then heated and pressurized by the heat pressure roller 440 while sandwiched between the two sheets, and the sheets and the paper P are heat-pressed together before being discharged from the device.

[0107] In this case, when the heat-pressure roller 440 is heated by a heat source such as a heater, and the temperature of the bearing supporting the heat-pressure roller 440 rises, there is a risk that FP / UFP may be generated from the lubricating substance adhering to the bearing. Therefore, by applying the present invention to a laminating processing apparatus 401 equipped with such a heat-pressure roller 440, it is possible to suppress the temperature rise of the bearing holding the heat-pressure roller 440 and effectively suppress the generation of FP / UFP. [Explanation of symbols]

[0108] 1: Image forming apparatus 2: Bottle storage section 2Y, 2M, 2C, 2K: Toner bottles; 3: Transfer device 4Y, 4M, 4C, 4K: Imaging section 5: Photoconductor 6: Charging device 7: Developing device 8: Cleaning equipment 9: Exposure equipment 10: Paper tray 11: Paper roller 12: Timing roller vs. 13: Paper output roller 14: Output tray 20: Fuser unit 21: Fixing belt (rotating body) 22: Pressure roller (pressure component) 22a: Core metal 22b: Elastic layer 22c: Release layer 23: Halogen heater (heat source) 24: Nip forming member 24a: Base pad 24b: Sliding seat 25: Stay 26: Reflective material 26: Reflective material 27: Shielding material 28: Temperature sensor 30: Intermediate transfer belt 31: Primary transfer roller 32: Secondary transfer backup roller 33: Cleaning backup roller 34: Tension roller 35: Belt cleaning device 36: Secondary transfer roller 40: Flange member (rotating body holding member) 40a: Cylindrical section (first cylindrical section) 40b: Inner circumferential surface 40c: Flange 40d: Slope 40e: Ring groove 40e: Ring groove 40f: Inclined groove 40g: Ring groove 40h: Helical inclined groove 40i: Annular groove 40j: Second cylindrical section 40k: Annular groove 40m: Notch LA: Lubricating substance N: Nip section P: Paper (transferred object) T: Toner image [Prior art documents] [Patent Documents]

[0109] [Patent Document 1] Japanese Patent Publication No. 2005-592335 (Tapered shape 23a2 in Figure 6) [Patent Document 2] Japanese Patent Publication No. 2007-72105 (Inclined groove of the rotating guide part in Figure 4)

Claims

1. A heating device comprising a rotating body that is rotatably held, a heating source that heats the inner circumferential surface of the rotating body, a rotating body holding member that holds the inner circumferential surfaces of both longitudinal ends of the rotating body, and a liquid or semi-solid lubricating substance that adheres to the rotating body holding member, wherein the rotating body holding member is A holding portion that slides against the inner circumferential surface of both ends of the rotating body, The rotating body has flanges that extend radially outward from the rotating body, sandwiching both longitudinal ends of the rotating body. An inclined surface formed from the longitudinal outer end of the holding portion toward the flange portion, and composed of a conical surface that slopes toward the direction away from the inner circumferential surface of the opposing rotating body as it moves from the holding portion toward the flange portion, A heating device characterized by having the following features.

2. The heating device according to claim 1, characterized in that the wall thickness of the rotating body holding member in the radial direction perpendicular to the longitudinal direction is 1.1 mm or more.

3. The heating device according to claim 1, characterized in that the inclined surface is an inclined groove.

4. The heating device according to claim 3, characterized in that the inclined grooves are provided in a plurality of directions in the rotational direction of the rotating body.

5. The heating device according to claim 3, characterized in that the inclined grooves are helical inclined grooves provided in a plurality in the rotational direction of the rotating body.

6. The heating device according to claim 5, characterized in that the helical inclined grooves are a plurality of helical inclined grooves on the outer circumferential surface of the upper part of the holding portion, inclined toward the inner surface of the flange portion in the direction of rotation of the rotating body.

7. The heating device according to claim 4, characterized in that a plurality of inclined grooves are formed at equal intervals in the circumferential direction of the holding portion.

8. The heating device according to claim 6, characterized in that the plurality of spiral inclined grooves are formed at equal intervals in the circumferential direction of the holding portion.

9. A heating device according to any one of claims 1 to 8, characterized in that a groove is formed between the base of the flange and the retaining portion.

10. A heating device comprising a rotating body that is rotatably held, a heating source that heats the inner circumferential surface of the rotating body, a rotating body holding member that holds the inner circumferential surfaces of both longitudinal ends of the rotating body, and a liquid or semi-solid lubricating substance that adheres to the rotating body holding member, wherein the rotating body holding member is The first holding portion slides against the inner circumferential surfaces of both ends of the rotating body, A flange portion extending radially outward from the rotating body, sandwiching both longitudinal ends of the rotating body, An inclined surface formed from the longitudinal outer end of the first holding portion toward the flange portion, and composed of a conical surface that inclins toward the direction away from the inner circumferential surface of the opposing rotating body as it moves from the first holding portion toward the flange portion, A circumferential annular groove formed on the longitudinal inner side of the first retaining portion, A second retaining portion is formed on the longitudinal inner side of the annular groove with a smaller diameter than the first retaining portion, and is in close proximity to the inner circumferential surface of the rotating body without contact. A heating device characterized by having the following features.

11. A heating device according to any one of claims 1 to 10, A nip-forming member that can contact the inner circumferential surface of the rotating body, A pressing member is provided that presses against the nip-forming member via the rotating body to form a nip. A nip-forming apparatus characterized in that the object to be conveyed passes through the nip.

12. A fixing device characterized by fixing a toner image onto a recording medium through a recording medium on which a toner image is supported in the nip of the nip forming device according to claim 11.

13. An image forming apparatus characterized by having a nip forming apparatus according to claim 11 or a fixing apparatus according to claim 12.

Images