JP2023138283A - Heating device, fixing device, and image forming apparatus - Google Patents

Abstract

To prevent the generation of fine particles.SOLUTION: A heating device 20 comprises: a rotating body 21 that is held rotatably; a heat source 23 that heats the rotating body 21; rotating body holding members 27 that hold both ends in a longitudinal direction of the rotating body 21; and a liquid or semi-solid material that is adhered to the rotating body holding members 27 and has lubricity. The temperature of the rotating body holding members 27 is lower than the generation temperature of fine particles of the liquid or semi-solid material having lubricity.SELECTED DRAWING: Figure 3

Description

The present invention relates to a heating device, a fixing device, and an image forming device.

2. Description of the Related Art As an example of a heating device installed in an image forming apparatus such as a copying machine or a printer, a fixing device is known that heats a recording medium such as paper to fix an unfixed image on the recording medium to the recording medium.

In such a fixing device, sliding that occurs between members such as a nip forming member and a belt holding member (for example, see Patent Document 1 below) that slide relative to a rotating body such as a belt, and the rotating body. In order to reduce dynamic resistance, a lubricating substance such as oil or grease (hereinafter referred to as a "lubricant") is generally used. A substance having lubricating properties refers to a substance that is present between parts and reduces the frictional resistance between the parts.

Overseas, especially in Europe, concern about the environment is very high, and image forming devices such as copiers, multifunction devices, and printers that use electrophotographic processes also emit volatile organic compounds (VOCs) and ozone during image formation. There are various certification standards for , dust, fine particles, etc., and especially in German government research institutes, there is an eco-label system called "Blue Angel Mark", which allows only certified products and services to use the label. .

Even if a product is not certified with the Blue Angel Mark, it does not mean that it cannot be sold, but the fact that it is not certified is often perceived as a product that is not environmentally friendly. This tendency is particularly strong in public offices. Therefore, the presence or absence of Blue Angel Mark certification has a significant impact on product sales.

To receive the "Blue Angel Mark" certification, a product must pass a variety of tests, but the particulate test is particularly demanding. Specifically, when fine particles of 5.6 nm to 560 nm generated from an image forming apparatus are measured using a particle counter FMPS (Fast Mobility Particle Sizer), the number of fine particles obtained is 3.5 × 10 ¹¹ pieces/10 It is expected that the standards will become even stricter in the future. In this case, the number of fine particles does not depend on the type and state of the substance forming the fine particles, for example, there is no distinction between inorganic/organic matter, and there is no distinction between solid/liquid (mist). Only the size and number of fine particles are relevant.

It is said that fine particles are generated from various components that make up an image forming apparatus, but since the amount of fine particles generated increases significantly when only the fixing device is activated, it is assumed that the fixing device is the main cause of fine particle generation. It is known that In fact, when the aforementioned lubricants are heated to high temperatures, particulates are detected, so the lubricants are one of the sources of particulates. It is believed that by heating a lubricant to a high temperature, a small portion of the lubricant's components evaporate as a high-temperature gas, which is then cooled and condensed to form fine particles. There is a need to prevent lubricants from being exposed to high-temperature environments and to suppress the generation of fine particles from image forming apparatuses.

The present invention aims to suppress the generation of fine particles.

In order to solve the above problems, a heating device according to the present invention includes a rotating body that is rotatably held, a heat source that heats the rotating body, and a rotating body holding member that holds both longitudinal ends of the rotating body. and a substance having liquid or semi-solid lubricating properties that adheres to the rotating body holding member, wherein the temperature of the rotating body holding member is a temperature at which fine particles of the substance having liquid or semi-solid lubricating properties are generated. characterized by lower

According to the present invention, generation of fine particles can be suppressed.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view of the center of the fixing device according to the present embodiment. FIG. 2 is a perspective view of the fixing device according to the present embodiment. FIG. 3 is an end sectional view of the fixing device according to the present embodiment. FIG. 2 is a cross-sectional view of the end portion of the fixing device according to the present embodiment taken along the longitudinal direction of the fixing belt. FIG. 7 is a perspective view showing the mounting structure of the second shielding member. It is a figure which shows the temperature rise of the belt holding member in this embodiment and a conventional example in comparison. FIG. 3 is a diagram showing a comparison of the generation rate of fine particles in the present embodiment and a conventional example. FIG. 3 is a diagram showing a comparison of the number of fine particles generated in the present embodiment and a conventional example. FIG. 3 is a diagram showing the relationship between printing speed and the number of fine particles generated. FIG. 7 is a cross-sectional view of an end of a fixing device according to a second embodiment of the present invention taken along the longitudinal direction of a fixing belt. FIG. 7 is an end sectional view of a fixing device according to a third embodiment of the present invention. FIG. 7 is a cross-sectional view of an end of a fixing device according to a third embodiment of the present invention taken along the longitudinal direction of a fixing belt. It is a figure which compares and shows the generation rate of fine particles in a third embodiment of the present invention and a conventional example. FIG. 7 is a diagram showing a comparison of the number of fine particles generated in a third embodiment of the present invention and a conventional example. FIG. 7 is a diagram showing the configuration of a fixing device according to a fourth embodiment of the present invention. FIG. 7 is a diagram showing the configuration of a fixing device according to a fifth embodiment of the present invention. FIG. 7 is a diagram showing the configuration of a fixing device according to a sixth embodiment of the present invention. FIG. 7 is a diagram showing the configuration of a fixing device according to a seventh embodiment of the present invention. FIG. 3 is a cross-sectional view showing the configuration of another fixing device to which the present invention is applicable. 21 is an exploded perspective view of the fixing device shown in FIG. 20. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 23 is an exploded perspective view of the fixing device shown in FIG. 22. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 25 is an exploded perspective view of the fixing device shown in FIG. 24. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. FIG. 27 is a cross-sectional view of the fixing device shown in FIG. 26 taken along the longitudinal direction of the fixing belt. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 29 is an exploded perspective view of the fixing device shown in FIG. 28. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 31 is a cross-sectional view showing a holding structure for the pressure roller shown in FIG. 30. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 33 is a perspective view of the fixing device shown in FIG. 32. FIG. FIG. 3 is a diagram showing the relationship between the temperature of a lubricant and the concentration of fine particles generated. FIG. 3 is a perspective view of a sample container. FIG. 2 is a cross-sectional view of an end portion of a conventional fixing device taken along the longitudinal direction of a fixing belt. It is a figure which shows the temperature rise of the belt holding member in a conventional example. FIG. 3 is a diagram showing the generation rate of fine particles in a conventional example. 1 is a diagram showing one form of an inkjet image forming apparatus including a drying device. It is a figure showing an example of a drying device. 1 is a diagram showing one form of an image forming apparatus including a lamination processing device.

Hereinafter, the present invention will be explained based on the accompanying drawings. In addition, in each drawing for explaining the present invention, components such as members and components having the same function or shape are given the same reference numerals as much as possible so that they can be distinguished. Omitted.

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. Here, the "image forming apparatus" in this specification includes a printer, a copying machine, a facsimile machine, a printing machine, or a multifunction machine that combines two or more of these. Furthermore, "image formation" used in the following description means not only forming images with meaning such as characters and figures, but also forming images without meaning such as patterns. First, with reference to FIG. 1, the overall configuration and operation of an image forming apparatus according to this embodiment will be described.

As shown in FIG. 1, the image forming apparatus 100 according to the present embodiment includes an image forming section 200 that forms an image on a sheet-like recording medium such as paper, a fixing section 300 that fixes the image on the recording medium, The apparatus includes a recording medium supply section 400 that supplies a recording medium to the image forming section 200, and a recording medium discharge section 500 that discharges the recording medium to the outside of the apparatus.

The image forming section 200 includes four process units 1Y, 1M, 1C, and 1Bk as image forming units, and an exposure device that forms an electrostatic latent image on the photoreceptor 2 provided in each process unit 1Y, 1M, 1C, and 1Bk. 6, and a transfer device 8 for transferring an image onto a recording medium.

Each process unit 1Y, 1M, 1C, and 1Bk has basically the same configuration except that it contains toner (developer) of different colors of yellow, magenta, cyan, and black corresponding to the color separation components of a color image. be. Specifically, each of the process units 1Y, 1M, 1C, and 1Bk includes a photoreceptor 2 as an image carrier that carries an image on its surface, a charging member 3 that charges the surface of the photoreceptor 2, and a charging member 3 that charges the surface of the photoreceptor 2. The photoreceptor 2 includes a developing device 4 that supplies toner as a developer to form a toner image, and a cleaning member 5 that cleans the surface of the photoreceptor 2.

The transfer device 8 includes an intermediate transfer belt 11, a primary transfer roller 12, and a secondary transfer roller 13. The intermediate transfer belt 11 is an endless belt member, and is stretched by a plurality of support rollers. Four primary transfer rollers 12 are provided inside the intermediate transfer belt 11. Each primary transfer roller 12 contacts each photoreceptor 2 via the intermediate transfer belt 11, thereby forming a primary transfer nip between the intermediate transfer belt 11 and each photoreceptor 2. The secondary transfer roller 13 contacts the outer peripheral surface of the intermediate transfer belt 11 to form a secondary transfer nip.

The fixing unit 300 is provided with a fixing device 20 as a heating device that heats the recording medium onto which the image has been transferred. The fixing device 20 includes a fixing belt 21 that heats an image on a recording medium, a pressure roller 22 that contacts the fixing belt 21, and forms a nip (fixing nip), and the like.

The recording medium supply section 400 is provided with a paper feed cassette 14 that accommodates paper P as a recording medium, and a paper feed roller 15 that feeds the paper P from the paper feed cassette 14. Hereinafter, the "recording medium" will be explained as "paper," but the "recording medium" is not limited to paper. The "recording medium" includes not only paper but also an OHP sheet or cloth, a metal sheet, a plastic film, a prepreg sheet in which carbon fiber is pre-impregnated with a resin, and the like. In addition to plain paper, "paper" also includes cardboard, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, and the like.

The recording medium ejecting section 500 is provided with a pair of paper ejection rollers 17 for ejecting the paper P out of the image forming apparatus, and a paper ejection tray 18 on which the paper P ejected by the paper ejection rollers 17 is placed.

Next, the printing operation of the image forming apparatus 100 according to this embodiment will be described with reference to FIG.

When a printing operation is started in the image forming apparatus 100, the photoreceptors 2 of each process unit 1Y, 1M, 1C, and 1Bk and the intermediate transfer belt 11 of the transfer device 8 start rotating. Further, the paper feed roller 15 starts rotating, and the paper P is sent out from the paper feed cassette 14. The fed paper P comes into contact with the pair of timing rollers 16 and comes to rest, and the conveyance of the paper P is temporarily stopped until an image to be transferred to the paper P is formed.

In each of the process units 1Y, 1M, 1C, and 1Bk, first, the surface of the photoreceptor 2 is charged to a uniform high potential by the charging member 3. Next, the exposure device 6 exposes the surface (charged surface) of each photoreceptor 2 based on the image information of the document read by the document reading device or the print image information instructed to print from the terminal. As a result, the potential of the exposed portion decreases, and an electrostatic latent image is formed on the surface of each photoreceptor 2. The developing device 4 supplies toner to this electrostatic latent image, and a toner image is formed on each photoreceptor 2. When the toner images formed on each photoreceptor 2 reach the primary transfer nip (the position of the primary transfer roller 12) as each photoreceptor 2 rotates, they are transferred onto the rotating intermediate transfer belt 11 so as to overlap one another. be done. In this way, a full-color toner image is formed on the intermediate transfer belt 11. In addition, it is possible to form a monochrome image using any one of the process units 1Y, 1M, 1C, and 1Bk, or to form a two-color or three-color image using any two or three process units. You can also Further, after the toner image is transferred to the intermediate transfer belt 11, residual toner and the like on each photoreceptor 2 is removed by the cleaning member 5.

The toner image transferred onto the intermediate transfer belt 11 is conveyed to the secondary transfer nip (the position of the secondary transfer roller 13) as the intermediate transfer belt 11 rotates, and onto the paper P conveyed by the timing roller 16. transcribed into. After that, the paper P is conveyed to the fixing device 20, and the toner image on the paper P is heated and pressed by the fixing belt 21 and the pressure roller 22, and the toner image is fixed on the paper P. Then, the paper P is conveyed to the recording medium discharge section 500 and discharged to the paper discharge tray 18 by the paper discharge roller 17. This completes the series of printing operations.

Next, the basic configuration of the fixing device according to this embodiment will be explained based on FIGS. 2 and 3. FIG. 2 is a sectional view of the center portion of the fixing device according to the present embodiment, taken at a longitudinal center portion M (see FIG. 3) of the fixing belt 21. As shown in FIG. Note that the "longitudinal direction" of the fixing belt here refers to the direction indicated by the arrow X in FIG. It means the same direction as the width direction of the paper (the direction that intersects with the paper conveyance direction) passing through the nip section. Furthermore, "longitudinal direction" in the following description has the same meaning.

As shown in FIGS. 2 and 3, the fixing device 20 according to the present embodiment includes, in addition to the fixing belt 21 and the pressure roller 22, a heater 23, a nip forming member 24, a stay 25, and a reflecting member 26 ( (see FIG. 2), a belt holding member 27 (see FIG. 3), and a temperature sensor 28 (see FIG. 2).

The fixing belt 21 is a rotating body (first rotating body or fixing member) that contacts the unfixed toner carrying surface of the paper P and fixes the unfixed toner (unfixed image) to the paper P.

Specifically, the fixing belt 21 is constituted by an endless belt in which a base material, an elastic layer, and a release layer are laminated in order from the inner peripheral surface side to the outer peripheral surface side. The base material has a layer thickness of 30 to 50 μm and is made of a metal material such as nickel or stainless steel, or a resin material such as polyimide. The elastic layer has a layer thickness of 100 to 300 μm and is made of a rubber material such as silicone rubber, foamable silicone rubber, or fluororubber. Since the fixing belt 21 has the elastic layer, minute irregularities are not formed on the surface of the fixing belt 21 in the nip portion, so that heat is easily transferred to the toner image on the paper P evenly. The release layer has a layer thickness of 10 to 50 μm and is made of PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), PTFE (polytetrafluoroethylene), polyimide, polyetherimide, PES (polyether sulfide). It is made of materials such as Since the fixing belt 21 has a release layer, release properties (peelability) for the toner (toner image) are ensured. Further, in order to reduce the size and heat capacity of the fixing belt 21, it is preferable that the entire thickness is 1 mm or less and the diameter is 30 mm or less.

The pressure roller 22 is a rotating body (second rotating body or opposing member) that is arranged to face the outer circumferential surface of the fixing belt 21 .

Specifically, the pressure roller 22 includes a solid iron core material, an elastic layer provided on the outer peripheral surface of the core material, and a release layer provided on the outer peripheral surface of the elastic layer. The core material may be a hollow member. The elastic layer is formed of silicone rubber, foamable silicone rubber, fluororubber, or the like. The release layer is formed of a fluororesin such as PFA or PTFE.

The heater 23 is a heat source that heats the fixing belt 21. In this embodiment, a halogen heater is used as the heater 23. In addition to the halogen heater, the heater 23 may be a radiant heater such as a carbon heater or a ceramic heater, or may be an electromagnetic induction heating source. Further, in this embodiment, two heaters 23 are arranged inside the fixing belt 21, but the number of heaters 23 may be one, three or more.

The nip forming member 24 is a member that is disposed inside the fixing belt 21 and forms a nip portion N between the fixing belt 21 and the pressure roller 22 by receiving the pressing force of the pressure roller 22. The nip forming member 24 has a base pad 29 and a sliding sheet 30.

The base pad 29 is arranged continuously in the longitudinal direction X of the fixing belt 21 and is fixed to the stay 25. The shape of the nip portion N is determined by the base pad 29 receiving the pressing force of the pressure roller 22. As the material for the base pad 29, it is preferable to use a heat-resistant member having a heat-resistant temperature of 200° C. or higher. For example, common heat-resistant materials such as polyether sulfone (PES), polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polyether nitrile (PEN), polyamideimide (PAI), or polyether ether ketone (PEEK) Examples include polyester resins. By using such a heat-resistant material as the material for the base pad 29, thermal deformation of the base pad 29 in the fixing temperature range can be prevented, and the shape of the nip portion N can be stabilized. The shape of the nip portion N may be a concave shape as shown in FIG. 2, a flat shape, or another shape.

The sliding sheet 30 is a low-friction member interposed between the base pad 29 and the inner peripheral surface of the fixing belt 21 . Since the sliding sheet 30 is interposed between the base pad 29 and the fixing belt 21, the sliding resistance of the fixing belt 21 with respect to the base pad 29 is reduced. Note that if the base pad 29 itself is formed of a low-friction member, the sliding sheet 30 may not be provided.

The stay 25 is a support member that supports the nip forming member 24 from the side opposite to the pressure roller 22 side. Since the stay 25 supports the nip forming member 24, the deflection of the nip forming member 24 due to the pressure applied by the pressure roller 22 (particularly the deflection in the longitudinal direction of the fixing belt 21) is suppressed. As a result, a nip portion N having a uniform width can be obtained. The material of the stay 25 is preferably a ferrous metal material such as SUS or SECC in order to ensure rigidity.

The reflecting member 26 is a member that reflects radiant heat (infrared rays) emitted from the heater 23. The radiant heat emitted from the heater 23 is reflected to the fixing belt 21 by the reflecting member 26, so that the fixing belt 21 is efficiently heated. Further, the reflecting member 26 is interposed between the stay 25 and the heater 23 and also has the function of suppressing heat transfer to the stay 25. This makes it possible to suppress the flow of heat to members that do not directly contribute to fixing, thereby increasing the efficiency of energy consumption. As the material of the reflective member 26, a metal material such as aluminum or stainless steel can be used. In particular, when the reflective member 26 is configured by depositing silver with high reflectance on the surface of an aluminum base material, the heating efficiency is further improved.

The belt holding members 27 are a pair of rotating body holding members that rotatably hold the fixing belt 21 . As shown in FIG. 3, the belt holding member 27 is inserted inside the fixing belt 21 at both ends in the longitudinal direction, and rotatably holds the fixing belt 21 from the inside. Note that "both ends in the longitudinal direction" of the fixing belt 21 here and "ends in the longitudinal direction" of the fixing belt 21 in the following description mean only the ends of the fixing belt 21 in the longitudinal direction. Not limited to cases. “Both ends in the longitudinal direction” and “ends in the longitudinal direction” include the end edge of the fixing belt 21 at the end in the longitudinal direction, as well as the end edge of the fixing belt 21 divided into three equal parts in the longitudinal direction. Any position within one length is also included. Therefore, the belt holding member 27 is used not only to hold an area including the most longitudinal edge of the fixing belt 21 (longitudinal end) but also to hold an area that does not include the edge of the fixing belt 21 (longitudinal end). It may also be the case that a part) is retained.

Specifically, the belt holding member 27 includes an insertion part 27a having a C-shaped cross section that is inserted into the longitudinal end of the fixing belt 21, a regulating part 27b formed to have a larger outer diameter than the insertion part 27a, and a restriction part 27b that will be described later. It has a fixing part 27c fixed to the side plate of. The regulating portion 27b is formed to be larger than at least the outer diameter of the fixing belt 21, and regulates the shifting of the fixing belt 21 when it shifts in the longitudinal direction X (movement in the longitudinal direction). The insertion portion 27a rotatably holds the fixing belt 21 from inside by being inserted into the longitudinal end portion of the fixing belt 21.

Temperature sensor 28 is a temperature detection member that detects the temperature of fixing belt 21 . In this embodiment, a non-contact type temperature sensor is used as the temperature sensor 28, which is disposed in a non-contact manner with respect to the outer peripheral surface of the fixing belt 21. In this case, the temperature sensor 28 detects the ambient temperature near the outer peripheral surface of the fixing belt 21 as the surface temperature of the fixing belt 21. Further, the temperature sensor 28 is not limited to a non-contact type sensor, but may be a contact type sensor that comes into contact with the fixing belt 21 to detect the surface temperature. As the temperature sensor 28, for example, a known temperature sensor such as a thermopile, thermostat, thermistor, or NC sensor can be used.

The fixing device 20 according to this embodiment operates as follows.

When the pressure roller 22 rotates in the direction of the arrow in FIG. 2 by driving a drive source provided in the main body of the image forming apparatus, the fixing belt 21 rotates as the pressure roller 22 rotates. Further, the heater 23 generates heat, and the fixing belt 21 is heated by the heater 23 . At this time, the amount of heat generated by the heater 23 is controlled based on the temperature of the fixing belt 21 detected by the temperature sensor 28, so that the temperature of the fixing belt 21 becomes a predetermined fixing temperature (temperature at which image fixation is possible). controlled by. Then, in a state where the temperature of the fixing belt 21 has reached the fixing temperature, when the paper P carrying an unfixed image is conveyed between the fixing belt 21 and the pressure roller 22 (nip portion N), the fixing belt The paper P is heated and pressurized by the pressure roller 21 and the pressure roller 22, and the image on the paper P is fixed to the paper P.

Here, in the fixing device including the nip forming member 24 as described above, when the fixing belt 21 rotates, the fixing belt 21 slides with respect to the nip forming member 24, so that the fixing belt 21 and the nip forming member 24 are Sliding resistance occurs between. In order to reduce sliding resistance at this time, a lubricant such as silicone oil, silicone grease, fluorine grease, or fluorine oil is generally applied between the fixing belt 21 and the nip forming member 24. has been done. For example, the lubricant is contained in a sliding sheet 30 (see FIG. 2) disposed between the base pad 29 of the nip forming member 24 and the inner peripheral surface of the fixing belt 21, and the lubricant is contained in the sliding sheet 30 (see FIG. 2). As the lubricant oozes out, the lubricant is present between the nip forming member 24 and the fixing belt 21.

Further, as described above, in the configuration in which the fixing belt 21 is held by a pair of belt holding members 27, when the fixing belt 21 rotates, the fixing belt 21 slides with respect to each belt holding member 27. At this time, since sliding resistance also occurs between each belt holding member 27 and the fixing belt 21, in order to reduce the sliding resistance, the above-mentioned sliding resistance is also generated between each belt holding member 27 and the fixing belt 21. A lubricant such as is used.

As described above, in a configuration including sliding members such as the nip forming member 24 and the belt holding member 27, in order to improve the sliding properties of the fixing belt 21, silicone oil, silicone grease, fluorine grease, fluorine Lubricants such as oil are used. However, as the temperature of the fixing device increases, some of the low-molecular components of the lubricant volatilize and coagulate when cooled in the atmosphere, generating fine particles, which may be released from the fixing device. Here, "fine particles" are fine particles and ultrafine particles (hereinafter referred to as "FP/UFP") measured under measurement conditions for investigating the relationship shown in FIG. 34, which will be described later, and have a particle size of 5. The particles are 6 nm to 560 nm.

In recent years, as awareness of environmental issues has increased, measures to suppress the generation of FP/UFP emitted from products are desired, and there is also a need for the development of products that generate less FP/UFP in image forming devices. .

Therefore, in considering measures to suppress the generation of FP/UFP from the fixing device, the inventors first investigated the temperature rise of silicone oil and fluorine grease used as lubricants, and the FP generated from these lubricants. A test was conducted to investigate the relationship between the concentration of FP/UFP generated (number of FP/UFP generated per 1 cm ³ ). The results are shown in FIG.

In this test, a liquid or semi-solid lubricant substance in a sample container was heated in a 1 cubic meter chamber (ventilation number: 5 times) in accordance with JIS A 1901. As shown in FIG. 35, the sample container 1000 is a 50 mm x 50 mm x 5 mm aluminum plate with a recess 1000a having a diameter of 22 mm and a depth of 2 mm, and the sample is placed in the recess 1000a. The sample container 1000 containing the sample was placed on a hot plate of a heating device (Clean Hot Plate MH-180CS manufactured by As One, Controller MH-3CS manufactured by As One), and the sample was heated at a set temperature of 250°C. While monitoring the temperature of the hot plate, the number concentration of FP/UFP in the chamber was measured using a measuring device (Fast Mobility Particle Sizer (FMPS: Fast Mobility Particle Sizer, TSI; Model 3091). :30 seconds). Fluorine grease and silicone oil were used as lubricants, and the sample amount was 36 μl. The solid line in FIG. 34 indicates the number concentration of FP/UFP generated from fluorine grease, and the dashed-dotted line in the figure indicates the number concentration of FP/UFP generated from silicone oil. In addition, in FIG. 34, the temperature of the hot plate is shown on the horizontal axis, but since the temperature rise of the hot plate and the temperature rise of the lubricant change almost synchronously, here, the temperature of the hot plate is shown as the temperature of the lubricant. It is considered as the temperature of the agent.

As shown in Figure 34, in the fluorine grease shown by the solid line, FP/UFP begins to occur when the temperature reaches 185°C, and FP/UFP begins to occur when the temperature exceeds 194°C. The number concentration increased rapidly. On the other hand, in the silicone oil shown by the dashed-dotted line, FPs/UFPs begin to be generated when the temperature reaches 200℃, and the number concentration of FPs/UFPs that are generated suddenly increases when the temperature exceeds 210℃. Rose. The temperature at which the concentration rapidly increased was defined as the particle generation temperature, and was defined as the temperature at which the number concentration of FP/UFP in the chamber was 4000 particles/cm ³ or more.

In this way, FP/UFP occurs in fluorine grease when the temperature reaches 185°C, and FP/UFP occurs in silicone oil when the temperature reaches 200°C. In the device, there is a possibility that FP/UFP may be generated from the lubricant. Therefore, in order to effectively reduce such FP/UFP, it is important to suppress the temperature rise in the portion where FP/UFP is likely to occur.

However, until now, it has not been possible to identify from which part of the fixing device the FP/UFP occurs in large numbers. Therefore, the present inventors conducted a thorough study on the main sources of FP/UFP, and as a result, it was found that a large amount of FP/UFP is generated mainly from the lubricant adhering to the belt holding member. The reason and mechanism of occurrence will be explained below.

FIG. 36 is a cross-sectional view showing the configuration of a longitudinal end portion of a fixing belt in a conventional fixing device.

As shown in FIG. 36, the conventional fixing device includes a belt holding member 270 that holds the longitudinal ends of the fixing belt 210, similarly to the fixing device according to the embodiment of the present invention. A lubricant is applied to the outer peripheral surface of the belt holding member 270 in order to reduce the sliding resistance of the fixing belt 210. Note that even if the lubricant is not actively applied to the outer peripheral surface of the belt holding member 270, the lubricant interposed between the fixing belt and the nip forming member flows as the fixing belt rotates. As a result, it may adhere to the outer circumferential surface of the belt holding member 270.

Here, in a conventional fixing device, when a plurality of sheets are continuously passed and the fixing process is performed continuously, the area outside the maximum paper passing area (maximum recording medium passing area) W where the largest width paper passes is In the non-sheet passing area, heat is not easily consumed due to paper passing, so the temperature of the fixing belt 210 increases due to heat accumulation. Then, when the heat of the fixing belt 210 is transferred to the belt holding member 270 that holds the longitudinal end portion of the fixing belt 210, the temperature of the belt holding member 270 increases under the influence of the heat of the fixing belt 210. Further, as shown in FIG. 36, in a configuration in which the heat generating portion H of the heater 230 extends outside the maximum paper passing area W, the temperature increase of the fixing belt 210 in the non-paper passing area becomes more significant. , the temperature of the belt holding member 270 also tends to increase significantly. As described above, in the conventional fixing device, as the temperature of the longitudinal end side of the fixing belt 210, which is a non-sheet passing area, increases, the temperature of the belt holding member 270 that holds the longitudinal end side of the fixing belt 210 becomes excessive. Since there is a possibility that the temperature rise may rise, some fixing belts 210 are provided with a shielding member 310 as shown in FIG. 36 as a measure to suppress the temperature rise. The shielding member 310 is provided between the heater 230 and the fixing belt 210 and between the heater 230 and the belt holding member 270 in the paper non-passing area, and is configured to prevent the heating from the heater 230 to the fixing belt 210 and the belt holding member 270. Shield from radiant heat.

However, since the shielding member 310 directly receives the radiant heat emitted from the heater 230 and becomes high in temperature, it has been found that the increase in the temperature of the shielding member 310 causes the temperature of the belt holding member 270 to increase. In particular, in a small fixing device, since the fixing belt 210 has a small diameter, the shielding member 310 and the belt holding member 270 are close to each other, and the belt holding member 270 is in an environment where it is easily affected by the heat of the shielding member 310. When the temperature of the belt holding member 270 exceeds the temperature at which FP/UFP occurs as described above due to the influence of heat of the shielding member 310 and the influence of heat in the non-paper passing area of the fixing belt 210, the belt The temperature of the lubricant adhering to the holding member 270 increases, and FP/UFP is generated from the lubricant. As described above, in the conventional fixing device, since the temperature rise of the belt holding member 270 could not be effectively suppressed, FP/UFP may be generated from the lubricant as the temperature of the belt holding member 270 rises.

Here, the present inventors conducted a test to investigate the rate of generation of FP/UFP (number of generation per unit time) in a conventional fixing device. FIG. 37 shows the temperature rise of the belt holding member when the conventional fixing device was used to continuously pass paper for 10 minutes to perform the fixing process, and FIG. shows the generation rate of FP/UFP resulting from

First, the temperature rise of the belt holding member shown in FIG. 37 will be explained. This temperature rise is the result of measuring the temperature of the belt holding member during 10 minutes of continuous sheet feeding using a thermocouple. According to the results shown in FIG. 37, in the conventional fixing device, the temperature of the belt holding member and the FP/UFP derived from silicone oil increase rapidly around 3 minutes after the start of continuous paper feeding. The temperature exceeded 210°C, and rose to 235°C after another 10 minutes. Moreover, at this time, the temperature of the shielding member had risen to 340°C. As described above, from the results shown in FIG. 37, in the conventional fixing device, when the shielding member becomes high temperature, the belt holding member is affected by the heat of the shielding member and reaches a temperature exceeding the FP/UFP generation temperature. I found out that I can get it.

Next, the generation speed of FP/UFP shown in FIG. 38 was determined by installing an image forming apparatus equipped with a conventional fixing device in a test chamber (a chamber with a volume of 2.18 ^m3 ) and continuously passing paper through for 10 minutes. The results of measuring the FP/UFP generation rate (the number of FP/UFP generation per second) when outputting a blank page are shown. The printing speed during continuous paper feeding at this time was 60 ppm (Page Par Minutes). Furthermore, the reason why the paper was output in a blank state was to prevent FP/UFP generated from wax in the toner from being included in the measurement target. The measurement target was FP/UFP with a particle size of 5.6 [nm] to 560 [nm] as defined in the Blue Angel Standard.

As can be seen from FIG. 38, in an image forming apparatus equipped with a conventional fixing device, FP/UFP begins to occur around 3 minutes after the temperature of the belt holding member exceeds 200°C (see FIG. 37). As the temperature of the belt holding member further increased, the number of FP/UFPs (generation rate) also increased. As a result, the number of FP/UFP generated in 10 minutes exceeded 4.0×10 ¹¹ .

As described above, from the test results shown in FIGS. 37 and 38, in a conventional fixing device and an image forming apparatus equipped with the same, when the fixing device is operated for 10 minutes and paper is continuously passed through, the belt holding member is It was found that the number of FP/UFPs generated increased significantly as the temperature increased. From this, it can be said that the lubricant adhering to the belt holding member is the source of FP/UFP. Therefore, in order to effectively reduce the number of FPs/UFPs discharged from the fixing device, it is important to suppress the temperature rise of the belt holding member and the temperature rise of the lubricant adhering to the belt holding member. It can be said that there is.

Therefore, in the embodiment of the present invention, the following measures are taken to suppress the temperature rise of the belt holding member.

FIG. 4 is an end sectional view of the fixing device according to the embodiment of the present invention, cut at the longitudinal end of the fixing belt, and FIG. FIG.

As shown in FIGS. 4 and 5, the fixing device 20 according to the present embodiment includes a shielding member 31 between the heater 23 and the belt holding member 27, as in the conventional fixing device shown in FIG. We are prepared. The structure and function of this shielding member 31 are basically the same as the structure and function of the shielding member 310 shown in FIG. 36. Supplementally, the shielding member 31 is fixed to the stay 25 and is formed in an arc shape along the inner peripheral surface of the fixing belt 21 .

Here, if the shielding member 31 is referred to as a "first shielding member" for convenience, in this embodiment, another shielding member is provided between the first shielding member 31 and the belt holding member 27. A second shielding member 32 is provided. 4 and 5, only the configuration of one end side of the fixing belt 21 in the longitudinal direction 32 are provided.

The second shielding member 32 is attached to be sandwiched between a shielding portion 32a formed in an arc shape along the inner circumferential surface of the fixing belt 21, the belt holding member 27, and the side plate 33 (see FIG. 5). It has a mounting portion 32b. As shown in FIG. 6, the mounting portion 32b is provided with a hole 32c as an engaging portion that engages with a convex portion 27d provided on the fixing portion 27c of the belt holding member 27. The second shielding member 32 is attached to the belt holding member 27 by inserting the convex portion 27d of the belt holding member 27 into the hole 32c. Furthermore, the screws 34 are inserted into the respective screw insertion holes 27e and 32d provided in the fixing part 27c of the belt holding member 27 and the second shielding member 32, and the screws 34 are fastened to the side plate 33, so that the second The shielding member 32 is sandwiched and fixed between the belt holding member 27 and the side plate 33.

The first shielding member 31 is made of a stainless steel plate, and suppresses heat transfer to the belt holding member 27 by blocking radiant heat (infrared rays) emitted from the heater 23 to the belt holding member 27. do. On the other hand, the second shielding member 32 is made of a copper plate having higher thermal conductivity than the first shielding member 31, and shields the transfer of heat from the first shielding member 31 to the belt holding member 27. , the received heat is released to the side plate 33 and the transfer of heat to the belt holding member 27 is suppressed. In particular, in this embodiment, since the side plate 33 is made of a metal material having higher thermal conductivity than the belt holding member 27 made of a heat-resistant resin material, the heat of the second shielding member 32 is transferred to the side plate. 33 can be effectively released.

In this way, the first shielding member 31 and the second shielding member 32 both function as a heat transfer suppressing member that suppresses transfer of heat from the heater 23 to the belt holding member 27. Thereby, the transfer of heat to the belt holding member 27 can be effectively suppressed, and the temperature rise of the belt holding member 27 can be suppressed to a higher degree than before.

FIG. 7 shows the temperature rise of the belt holding member during 10 minutes of continuous paper passing when the fixing device according to the present embodiment is used to continuously pass paper, and FIG. 8 shows the temperature rise of the FP/UFP at that time. Indicates the rate of occurrence (number of occurrences per unit time). In each figure of FIG. 7 and FIG. 8, the solid line is the result of this embodiment, and the broken line is the result of the conventional example shown for comparison. Note that the conditions for conducting this test are the same as those for the conventional fixing device shown in FIGS. 37 and 38 above.

As can be seen from FIG. 7, in this embodiment, the temperature rise of the belt holding member could be significantly suppressed compared to the conventional example. In the conventional example, the temperature of the belt holding member exceeds 210°C, which is the temperature at which FP/UFP derived from silicone oil rapidly increases, whereas in the present embodiment, the temperature of the belt holding member exceeds 210°C. It was never exceeded. Furthermore, in this embodiment, the temperature of the belt holding member did not exceed 194° C., which is the temperature at which FP/UFP derived from fluorine grease rapidly increases.

Therefore, as shown in FIG. 8, in this embodiment, the occurrence of FP/UFP could be suppressed more effectively than in the prior art. In the conventional example, FP/UFP began to occur after 3 minutes had passed after the start of paper feeding, and the number of FP/UFP occurrences (occurrence speed) further increased thereafter, but in this embodiment, after the start of paper feeding, The generation of FP/UFP could be effectively suppressed even after 3 minutes.

Further, FIG. 9 is a diagram showing a comparison of the number (cumulative number) of fine particles (FP/UFP) generated in this embodiment and the conventional example, and from the results shown in FIG. 9, in this embodiment, It can be seen that the number of FP/UFP occurrences was significantly reduced compared to the conventional example.

As described above, in the present embodiment, the fixing device includes a heat transfer suppressing member disposed between the heater 23 and the belt holding member 27 as a means for suppressing the temperature rise of the belt holding member (heat transfer suppressing member). In addition to the first shielding member 31 (first heat transfer suppressing member), a second shielding member 32 (second heat transfer suppressing member) disposed between the first shielding member 31 and the belt holding member 27 Therefore, the temperature of the belt holding member during 10 minutes of continuous printing can be suppressed to 210° C. or lower, at which FP/UFP derived from silicone oil rapidly increases. As a result, the fixing device according to the present embodiment can significantly reduce the number of FP/UFP generated from silicone oil compared to the conventional example.

In addition, from the perspective of more reliably reducing FP/UFP generated from the lubricant on the belt holding member, it is important to note that the temperature of the belt holding member during printing is such that the FP/UFP generated by the lubricant on the belt holding member is reduced. Preferably, the temperature is lower than the temperature. In general, image forming apparatuses in the market are mostly used for continuous printing within a few minutes, and it is rare to perform continuous printing for more than 5 minutes. Therefore, in order to suppress the generation of FP/UFP, it is sufficient if the temperature of the belt holding member during 10 minutes of continuous printing can be lower than the FP/UFP generation temperature of the lubricant on the belt holding member.

In addition, in order to more effectively suppress the generation of FP/UFP derived from silicone oil, the temperature of the belt holding member during 10 minutes of continuous printing should be kept below 200°C, which is the generation temperature of FP/UFP derived from silicone oil. It is preferable to suppress it. Furthermore, by suppressing the temperature of the belt holding member to 194° C. or lower during 10 minutes of continuous printing, generation of FP/UFP derived from fluorine grease can also be suppressed. Further, by suppressing the temperature of the belt holding member to 185° C. or lower during 10 minutes of continuous printing, generation of FP/UFP derived from fluorine grease can be more effectively suppressed. Further, when using silicone grease instead of silicone oil, the same effect can be obtained by controlling the temperature of the belt holding member in the same way as in the case of silicone oil. Further, even when fluorine oil is used instead of fluorine grease, the same effect can be obtained by controlling the temperature of the belt holding member as in the case of fluorine grease.

Here, the above-mentioned "temperature of the belt holding member during 10 minutes of continuous printing" means the temperature of the belt holding member measured by the following procedure. The temperature measurement procedure is as follows: First, install the image forming apparatus equipped with the fixing device (heating device) in a measurement room in a 23°C environment, turn on the power to the image forming apparatus, and start up the image forming apparatus. For example, the print instruction is issued after 60 minutes have passed. As for the printing conditions, the printing speed is set as the default setting, and the printing speed is set to the fastest mode. In addition, the paper to be used has a basis weight of 70 g/m ² and is A4 size or letter size. If the paper can be passed horizontally, the paper is passed horizontally, and if the paper cannot be passed horizontally, the paper is passed vertically. "Horizontal paper feeding" here means that the long side of the paper is transported in a direction perpendicular to the transport direction, and "vertical paper feeding" means that the paper is transported in a direction in which the short side of the paper is perpendicular to the transport direction. means that it is transported by Then, the temperature of the belt holding member is measured using a thermocouple for 10 minutes, with printing starting at the time when the first sheet of paper is discharged. However, if the time during which continuous printing is possible is less than 10 minutes due to the capacity of the paper ejection tray and the capacity of the paper feeding tray, the temperature of the belt holding member during the continuous printing time is measured. In addition to the measurement method specified above, measurement may be performed using an apparatus and conditions that comply with Blue Angel's particulate standards.

Further, the fixing device according to the present embodiment has the following configuration in order to effectively suppress the temperature rise of the belt holding member.

Specifically, as shown in FIGS. 4 and 5, a gap S is provided between the shielding portion 32a of the second shielding member 32 and the first shielding member 31. Therefore, even if the first shielding member 31 is heated by the heater 23 and its temperature rises, due to the heat insulation effect of the air layer (gap S) between the first shielding member 31 and the second shielding member 32, Heat from the first shielding member 31 is less likely to be transmitted to the second shielding member 32. This makes it difficult for the temperature of the second shielding member 32 to rise, so that the temperature rise of the belt holding member 27 can also be effectively suppressed.

Further, it is preferable that the gap S is provided over at least the range in the longitudinal direction X of the fixing belt 21 where the heat generating portion H of the heater 23 is arranged. Note that the "heat generating part" of the heater 23 in this embodiment is the part of the tungsten wire housed in the glass tube of the halogen heater that mainly generates heat, and specifically, the part where the tungsten wire is wound. means. Strictly speaking, even the straight portion where the tungsten wire is not wound generates a little heat when energized, but such a portion that does not primarily generate heat is not included in the heat generating portion.

In the range where the heat generating part H of the heater 23 is arranged, the temperature of the first shielding member 31 tends to rise by directly receiving the radiant heat emitted from the heater 23. It is preferable that the first shielding member 31 and the second shielding member 32 are arranged with a gap S between them (in a non-contact manner). Thereby, the transfer of heat from the first shielding member 31 to the second shielding member 32 can be effectively suppressed, and the rise in temperature of the belt holding member 27 can also be effectively suppressed.

Further, in order to ensure a gap S between the first shielding member 31 and the second shielding member 32, it is preferable that the first shielding member 31 and the second shielding member 32 be made of a plate material as thin as possible. . For example, the thickness of the second shielding member 32 is preferably 0.15 mm or more and 0.6 mm. In this embodiment, the first shielding member 31 is made of a stainless steel plate with a thickness of 0.3 mm, and the second shielding member 32 is made of a copper plate with a thickness of 0.15 mm.

Moreover, the material of the second shielding member 32 may be steel such as stainless steel (SUS), aluminum, etc. other than copper. Moreover, it is preferable that the second shielding member 32 is made of a material having a thermal conductivity of 10 W/m·k or more so as to effectively dissipate heat.

Moreover, in this embodiment, as shown in FIG. The member 32 is held in a non-contact manner with respect to the insertion portion 27a of the belt holding member 27. As described above, since the second shielding member 32 is not in contact with the insertion part 27a of the belt holding member 27, the heat of the second shielding member 32 is difficult to be transmitted to the insertion part 27a. The temperature rise of the lubricant adhering to the outer peripheral surface of 27a can also be effectively suppressed.

In the above description of this embodiment, fluorinated grease, fluorinated oil, silicone oil, and silicone grease have been cited as examples of substances that generate FP/UFP, but the present invention is applicable to liquid or semi-solid substances other than these. It is also applicable when a lubricating substance (a substance having lubricating properties) is used. In the present invention, a lubricating substance (a substance having lubricating properties) refers to a substance that is present between parts and reduces the frictional resistance between the parts. According to the present invention, even if a liquid or semi-solid lubricating substance other than fluorine grease, fluorine oil, silicone oil, or silicone grease is contained in the fixing device, the temperature rise of the belt holding member can be prevented. Since it is possible to suppress the temperature increase of the lubricating substance adhering to the belt holding member, it is possible to effectively suppress the occurrence of FP/UFP. In addition, if two or more types of lubricants are attached to the belt holding member, the temperature of the belt holding member during continuous printing for 10 minutes should be lower than the lower of the FP/UFP generation temperatures of these lubricants. It is preferable to control the temperature to be low.

Furthermore, the temperature rise of the belt holding member, which causes FP/UFP, becomes more pronounced in image forming apparatuses that pass a large number of sheets per unit time. If applied, great effects can be expected. According to FIG. 10, which shows the relationship between print speed and the number of FP/UFPs generated, the number of FPs/UFPs generated from the fixing device during 10 minutes of continuous printing is greater than 50 ppm (Page Par Minutes) when the print speed exceeds 50 ppm (Page Par Minutes). Especially from around the area. Therefore, the present invention can be expected to have greater effects when applied to a fixing device or an image forming apparatus with a printing speed of 50 ppm or more. Furthermore, as shown in FIG. 5, even in the case where the heater 23 is disposed inside the belt holding member 27, the temperature of the belt holding member 27 tends to rise. Great effects can be expected by applying the invention.

Next, an embodiment of the present invention different from the above embodiment (first embodiment) will be described. In the following description, parts that are different from the above embodiment will be mainly described, and since the other parts have basically the same configuration, the description will be omitted as appropriate.

FIG. 11 is a diagram showing the configuration of the second embodiment of the present invention.

In the second embodiment shown in FIG. 11, the second shielding member 32 is attached to the side plate 33 via a bracket 35 as an attachment member. Specifically, the bracket 35 is fixed to the surface of the side plate 33 opposite to the surface on the belt holding member 27 side, and the second shielding member 32 is fixed to the surface of the bracket 35 opposite to the surface fixed to the side plate 33. A mounting portion 32b is attached.

In this case, the second shielding member 32 is not attached so as to be sandwiched between the side plate 33 and the belt holding member 27 as in the first embodiment. Transfer of heat to the member 27 can be suppressed. That is, since the second shielding member 32 is arranged in a non-contact manner (not in direct contact) with the belt holding member 27, the heat of the second shielding member 32 is prevented from being transmitted to the belt holding member 27. It can be suppressed. Therefore, according to the configuration of the second embodiment, the temperature rise of the belt holding member 27 can be suppressed more effectively.

12 and 13 are diagrams showing the configuration of a third embodiment of the present invention.

In the third embodiment shown in FIGS. 12 and 13, the second shielding member 32 is not made of a member with high thermal conductivity as in the first embodiment, but is made of a member with low thermal conductivity. has been done. In this case, the second shielding member 32 made of a material with low thermal conductivity is interposed between the first shielding member 31 and the belt holding member 27, so that the heat of the first shielding member 31 is reduced. This makes it difficult for the light to be transmitted to the belt holding member 27. Thereby, the temperature rise of the belt holding member 27 can be effectively suppressed. That is, the second shielding member 32 in the third embodiment functions as a heat transfer suppressing member (second heat transfer suppressing member) that suppresses transfer of heat to the belt holding member 27 due to its heat insulating effect.

In this embodiment, the second shielding member 32 is held between the first shielding member 31 and the belt holding member 27, but the second shielding member 32 is held by the first shielding member 31. It may also be held by being integrally fixed. Further, as shown in FIG. 13, in addition to the case where the second shielding member 32 is in contact with the first shielding member 31 and the belt holding member 27, the second shielding member 32 is in contact with the first shielding member 31 and the belt holding member 27. 27 may be arranged in a non-contact manner. The thermal conductivity of the second shielding member 32 is preferably 0.05 W/m·k or less in order to effectively suppress heat transfer to the belt holding member 27. For example, it is preferable that the second shielding member 32 is made of a member having low thermal conductivity and heat resistance, such as glass wool.

FIGS. 14 and 15 show the rate of occurrence of FP/UFP and the number of occurrences (cumulative number) during 10 minutes of continuous sheet feeding when using the fixing device according to the third embodiment. In this case as well, the test conditions are the same as those for the conventional fixing device. Moreover, in each figure of FIG. 14 and FIG. 15, the solid line shows the result of the third embodiment, and the broken line shows the result of the conventional example.

As shown in FIGS. 14 and 15, in the third embodiment as well, the number of FP/UFPs generated could be significantly reduced compared to the conventional example. Therefore, even in a configuration using the second shielding member 32 having a heat insulating function as in the third embodiment, it is possible to obtain the same effects as in each of the above embodiments.

Furthermore, the following configuration and method are also effective as a method of suppressing the temperature rise of the belt holding member.

In the fourth embodiment of the present invention shown in FIG. 16, a cooling device 36 for cooling the belt holding member 27 is provided. The cooling device 36 includes a suction fan 37 as an airflow generating member and a duct 38. The intake port 38a of the duct 38 is arranged to face both ends in the longitudinal direction of the fixing belt 21 where the belt holding member 27 is arranged.

Further, as shown in FIG. 16, in this embodiment, a counting unit 102 that counts the number of consecutively printed sheets and a memory that stores a predetermined number of consecutively printed sheets that is a criterion for determining whether or not to operate the cooling device 36 are provided. A control device 101 is provided, which includes a determination unit 104 that determines whether or not to operate the cooling device 36 based on information obtained from the counting unit 102 and the storage unit 103. The number of continuous prints stored in the storage unit 103 is based on the correlation between the number of continuous prints and the temperature of the belt holding member 27 obtained through experiments, or the correlation between the number of continuous prints and the temperature of the lubricant on the belt holding member 27. Based on the relationship, the number of consecutive prints at which FP/UFP can occur from the lubricant on the belt holding member 27 is specified in advance, and is set to a value smaller than the specified number of consecutive prints. For example, when silicone oil is used as a lubricant, the number of continuous prints at which the temperature of the belt holding member 27 reaches 210°C at which FP/UFP derived from silicone oil can be generated is specified, and the number of continuous prints is determined from the specified number of continuous prints. The smaller number of sheets is set as a predetermined number of consecutive prints that serves as a determination criterion.

In the fourth embodiment configured as described above, the number of consecutive prints is counted by the counting unit 102, and when the counted number of consecutive prints reaches a predetermined number of consecutive prints stored in the storage unit 103, The cooling device 36 operates according to instructions from the determination unit 104. As a result, the suction fan 37 starts rotating, and air (hot air) near the belt holding member 27 is sucked through the duct 38. Further, since an air current is generated around the belt holding member 27, the belt holding member 27 is air-cooled, and an increase in temperature of the belt holding member 27 is suppressed. In addition to the above-mentioned suction fan 37, the airflow generating member that generates the airflow around the belt holding member 27 may be a blowing fan that blows air toward the fixing device 20 (belt holding member 27). .

As described above, in the fourth embodiment, when the counted number of consecutive prints reaches the predetermined number of consecutive prints, the cooling device 36 is activated, so that the number of consecutive prints is reduced from the lubricant on the belt holding member 27. The temperature of the belt holding member 27 can be lowered before the number of consecutive prints reaches a point where FP/UFP can occur. Here, the above-mentioned "when the counted number of consecutive prints reaches the predetermined number of consecutive prints" refers to the moment when the counted number of consecutive prints reaches the predetermined number of consecutive prints, as well as the number of consecutive prints that were counted. exceeds a predetermined number of consecutive prints and does not exceed the number of consecutive prints at which FP/UFP can occur from the lubricant on the belt holding member 27. Therefore, in this embodiment, the temperature of the belt holding member 27 can be lowered before FP/UFP is generated from the lubricant on the belt holding member 27, and the generation of FP/UFP can be avoided.

Further, as in the fifth embodiment of the present invention shown in FIG. 17, the temperature detected by the temperature sensor 39 may be used as information for determining the operation timing of the cooling device 36. In this case, the temperature sensor 39, which is a temperature detection member, is arranged to face both ends of the pressure roller 22 in the longitudinal direction, and detects the surface temperature of both ends of the pressure roller 22 in the longitudinal direction. Furthermore, the storage unit 103 stores the temperature of the heating roller at which FP/UFP is not generated from the lubricant on the belt holding member 27. That is, the temperature of the pressure roller 22 stored in the storage unit 103 is based on the correlation between the temperature of the pressure roller 22 and the temperature of the belt holding member 27, or the temperature of the pressure roller 22 and the temperature on the belt holding member 27. Based on the correlation with the temperature of the lubricant, the temperature of the pressure roller 22 at which FP/UFP can occur from the lubricant on the belt holding member 27 is specified, and the temperature of the pressure roller 22 is determined to be higher than the specified temperature of the pressure roller 22. The temperature is set to a low value. Note that instead of the temperature of the pressure roller 22, the temperature detected by the temperature sensor 28 (see FIG. 2) that detects the temperature of the fixing belt 21 may be used.

In this embodiment, when the temperature detected by the temperature sensor 39 rises and reaches a predetermined temperature stored in the storage unit 103, the cooling device 36 is activated according to an instruction from the determination unit 104. As a result, the belt holding member 27 is air-cooled, and the temperature rise of the belt holding member 27 is suppressed, as in the above embodiment. Note that also in this embodiment, the cooling device 36 may be provided with a suction fan or may be provided with a blower fan.

Further, in this embodiment, since the cooling device 36 is activated when the detected temperature reaches a predetermined temperature, the temperature of the pressure roller 22 is reduced to prevent FP/UFP from occurring from the lubricant on the belt holding member 27. The temperature of the belt holding member 27 can be lowered before the temperature of the pressure roller 22 reaches the desired temperature. Here, the above-mentioned "when the detected temperature reaches a predetermined temperature" refers to the moment when the detected temperature reaches the predetermined temperature, as well as the moment when the detected temperature exceeds the predetermined temperature and the lubricant on the belt holding member 27 This refers to the timing at which the temperature of the pressure roller 22 does not exceed the temperature at which FP/UFP can be generated from the agent. Thereby, also in this embodiment, the occurrence of FP/UFP can be avoided.

In each of the embodiments shown in FIGS. 16 and 17, the cooling device 36 is used to lower the temperature of the belt holding member 27, but instead of using the cooling device 36, the printing speed (unit time It is also possible to adopt a method of reducing the number of prints per print.

A sixth embodiment of the present invention shown in FIG. 18 is an embodiment using a method of reducing printing speed. In this case, the control device 101 operates based on information obtained from the counting section 102 that counts the number of consecutively printed sheets, the storage section 103 that stores a predetermined number of consecutively printed sheets, and the counting section 102 and the storage section 103. A determination unit 104 is provided that determines whether or not to reduce the print speed. The number of continuous prints stored in the storage unit 103 is the same as in the above embodiment, and is set to a value smaller than the number of continuous prints at which FP/UFP is assumed to occur from the lubricant on the belt holding member 27. .

In the present embodiment, when the counted number of consecutive prints reaches the number of consecutive prints stored in the storage unit 103, the print speed is reduced according to an instruction from the determination unit 104. That is, it controls the image forming operation in the image forming section 200, the paper feeding operation in the recording medium supplying section 400, and the conveying speed of the paper conveying device. Along with this, the rotational drive of the pressure roller 22 and the amount of heat generated by the heater 23 are also controlled.

By lowering the print speed in this way, the number of sheets passed per unit time in the fixing device 20 is reduced, so the amount of heat generated by the heater 23 can be reduced. Thereby, the temperature of the belt holding member 27 can be suppressed. Furthermore, in this embodiment, since the printing speed can be reduced before FP/UFP is generated from the lubricant, it is possible to prevent the occurrence of FP/UFP in the same way as in the above embodiment. It is.

Further, as in the seventh embodiment of the present invention shown in FIG. 19, it may be determined whether or not to reduce the printing speed based on the temperature of the pressure roller 22 detected by the temperature sensor 39. . In the storage unit 103 of this embodiment, as in the above embodiment, the temperature of the pressure roller 22 at which FP/UFP is assumed to be generated from the lubricant on the belt holding member 27 is set to a value lower than that of the pressure roller 22. Temperature is memorized. In this case, when the temperature detected by the temperature sensor 39 rises and reaches a predetermined temperature stored in the storage unit 103, the number of prints is reduced. Thereby, the temperature of the belt holding member 27 can be lowered before the occurrence of FP/UFP, so that the occurrence of FP/UFP can be avoided. Note that in this embodiment as well, the temperature detected by the temperature sensor 28 that detects the temperature of the fixing belt 21 may be used instead of the temperature of the pressure roller 22.

Although each embodiment of the present invention has been described above, the present invention is not limited to the configuration of each of the above-described embodiments, and can be modified as appropriate without departing from the gist of the invention. In the above embodiment, the first shielding member 31 and the second shielding member 32 are provided as heat transfer suppressing members that suppress the transfer of radiant heat from the heater 23 to the belt holding member 27. The first shielding member 31 may be omitted if the temperature of the belt holding member 27 inside can be suppressed to 210° C. or less.

Further, the present invention is applicable not only to the fixing device having the above-described configuration but also to fixing devices having various configurations. Below, some configurations of fixing devices to which the present invention can be applied will be illustrated.

The fixing device 40 shown in FIGS. 20 and 21 includes a fixing belt 41 as a first rotating body, a pressure roller 42 as a second rotating body, a heater 43 as a heat source, and a heat source holding member. It includes a heater holder 44, a pressure stay 45 as a support member, a thermistor 48 as a temperature detection member, and a flange 47 (see FIG. 21) as a rotating body holding member.

The functions and configurations of the fixing belt 41 and the pressure roller 42 shown in FIG. 20 are basically the same as those of the fixing belt 21 and the pressure roller 22 shown in FIG. 2 above.

The heater 43 is a ceramic heater having a plate-shaped substrate and a resistance heating element provided on the substrate, and generates heat by applying electricity to the resistance heating element. The heater 43 is arranged so as to be in contact with the inner peripheral surface of the fixing belt 41, and when the heater 43 generates heat, the fixing belt 41 is heated from the inside. Further, the heater 43 also functions as a nip forming member that forms a nip portion N with the fixing belt 41 sandwiched between the heater 43 and the pressure roller 42 .

The heater holder 44 is a heating source holding member that holds the heater 43. The heater holder 44 is made of, for example, heat-resistant resin. In this case, since the heater holder 44 is formed to have a semicircular arc-shaped cross section along the inner peripheral surface of the fixing belt 41, the rotation trajectory of the fixing belt 41 is regulated by the heater holder 44.

The pressure stay 45 is a support member that supports the heater holder 44. Since the pressure stay 45 supports the heater holder 44, the deflection of the heater holder 44 and the heater 43 due to the pressure applied by the pressure roller 42 is suppressed, and a uniform width is maintained between the pressure roller 42 and the fixing belt 41. A nip portion N is formed. The pressure stay 45 is preferably made of a metal material such as stainless steel (SUS) in order to ensure rigidity.

Further, the press stay 45 is provided with a thermistor 48 as a temperature detection member. The thermistor 48 detects the temperature of the fixing belt 41 by facing the inner peripheral surface of the fixing belt 41 in contact or non-contact.

The flanges 47 are a pair of holding members that hold both ends of the fixing belt 41 in the longitudinal direction, similarly to the belt holding member 27 described above. This flange 47 also has a backup part 47a as an insertion part inserted into the fixing belt 41, and a flange part 47b as a regulating part that regulates movement of the fixing belt 41 in the longitudinal direction. In this case, each flange 47 is held inserted into the fixing belt 41 by being urged toward each end of the fixing belt 41 by a biasing member such as a spring.

Even in the fixing device 40 having such a configuration, when the heater 43 generates heat, the temperature of the flange 47 increases, and the temperature of the lubricant adhering to the flange 47 increases, which may cause FP/UFP. Therefore, by applying the present invention to the fixing device 40 shown in FIGS. 20 and 21, it is possible to suppress the temperature rise of the flange 47 and suppress the occurrence of FP/UFP.

Next, the fixing device 50 shown in FIGS. 22 and 23 is a fixing device that includes a ceramic heater (heater 53) like the fixing device 40 shown in FIGS. 20 and 21 described above. Specifically, the fixing device 50 shown in FIGS. 22 and 23 includes a fixing belt 51 as a first rotating body, a pressure member 52 as a second rotating body, a heater 53 as a heat source, and a heat source. A heater holder 54 as a holding member, a reinforcing member 55 as a supporting member, a belt holding part 57 as a rotating body holding member (see FIG. 23), a heat sensitive element 58 as a temperature sensing member (see FIG. 23), and a cover. A member 59 (see FIG. 23) is provided.

The functions and configurations of the fixing belt 51, pressure member 52, heater 53, heater holder 54, reinforcing member 55, and belt holding section 57 shown in FIGS. 22 and 23 are the same as those of the fixing belt 51 shown in FIGS. 20 and 21. 41, pressure roller 42, heater 43, heater holder 44, pressure stay 45, and flange 47 are basically the same.

The heat sensitive element 58 is provided on the side of the heater holder 54 opposite to the surface that holds the heater 53, and detects the temperature of the heater 53 via the heater holder 54. The fixing belt 51 is maintained at a predetermined fixing temperature by controlling the heat generation of the heater 53 based on the detected temperature of the heat sensitive element 58.

The cover member 59 is a box-shaped member made of heat-resistant resin. The cover member 59 is disposed within the fixing belt 51 so as to face the heater holder 54 with the heat sensitive body 58 in between, so that the corresponding heat sensitive body 58 is covered by the cover member 59 .

In this way, the fixing device to which the present invention is applied may include the heat sensitive body 58 that detects the temperature of the heater 53 and the cover member 59 that covers the heat sensitive body 58.

Next, a fixing device 60 shown in FIGS. 24 and 25 is a fixing device that includes a halogen heater (heater 63) as a heat source, like the fixing device 20 shown in FIGS. 2 and 3 above. Specifically, the fixing device 60 shown in FIGS. 24 and 25 includes a fixing belt 61 as a first rotating body, a pressure roller 62 as a second rotating body, a heater 63 as a heat source, and a nip forming device. A member 64, a support part 65 as a support member, a reflection plate 66 as a reflection member, a holding frame 67 as a rotating body holding member (see FIG. 25), and a ring 68 as a sliding member (see FIG. 25). It is equipped with

The functions and configurations of the fixing belt 61, pressure roller 62, heater 63, nip forming member 64, support section 65, reflection plate 66, and holding frame 67 shown in FIGS. 24 and 25 are as shown in FIGS. 2 and 3. The fixing belt 21, pressure roller 22, heater 23, nip forming member 24, stay 25, reflecting member 26, and belt holding member 27 shown are basically the same. Note that the nip forming member 64 includes a metal base pad 640 and a fluororesin sliding sheet 641 interposed between the base pad 640 and the inner peripheral surface of the fixing belt 61.

The ring 68 is attached to the outer peripheral surface of the cylindrical portion 67a as an insertion portion of the holding frame 67 inserted into the fixing belt 61, and is attached to the longitudinal edge of the fixing belt 61 and the fixing plate as a regulating portion of the holding frame 67. 67b. When the fixing belt 61 rotates, the ring 68 rotates together with the fixing belt 61, or the fixing belt 61 slides against the low-friction ring 68, so that the fixing belt 61 and the holding frame 67 are separated. The sliding resistance that occurs between the two is reduced.

In this way, the fixing device to which the present invention is applied may include the ring 68.

Next, a fixing device 70 shown in FIGS. 26 and 27 is a fixing device that includes a halogen heater 73 as a heat source, similar to the fixing device 20 shown in FIGS. 2 and 3 above. Specifically, the fixing device 70 shown in FIGS. 26 and 27 includes a fixing belt 71 as a first rotating body, a pressure roller 72 as a second rotating body, a halogen heater 73 as a heat source, and a nip. It includes a forming member 74, a reflecting member 76, a belt supporting member 77 (see FIG. 27) as a rotating body holding member, a temperature sensor 78 as a temperature detecting member, and a guide member 79.

The fixing belt 71, pressure roller 72, halogen heater 73, nip forming member 74, reflective member 76, belt support member 77, and temperature sensor 78 shown in FIGS. 26 and 27 are the fixing belt 71 shown in FIGS. 2 and 3. 21, the pressure roller 22, the heater 23, the nip forming member 24, the reflecting member 26, the belt holding member 27, and the temperature sensor 28 have basically the same functions.

However, the reflecting member 76 shown in FIGS. 26 and 27 mainly reflects the radiant heat (infrared rays) emitted from the halogen heater 73 not to the fixing belt 71 but to the nip forming member 74. The reflective member 76 is formed to have a U-shaped cross section so as to cover the outside of the halogen heater 73, and an inner surface 76a of the reflective member 76 facing the halogen heater 73 is a reflective surface with high reflectance. Therefore, when radiant heat is emitted from the halogen heater 73, the radiant heat is reflected by the reflective surface 76a of the reflective member 76 toward the nip forming member 74.

As a result, the nip forming member 74 is heated by the radiant heat emitted toward the nip forming member 74 from the halogen heater 73 and the radiant heat reflected toward the nip forming member 74 by the reflecting member 76. Then, the heat of the nip forming member 74 is transferred to the fixing belt 21 at the nip portion N. That is, in this case, the nip forming member 74 not only forms the nip portion N, but also functions as a heat transfer member that transmits heat to the fixing belt 71 in the nip portion N. For this reason, the nip forming member 74 is made of a metal material such as copper or aluminum that has good thermal conductivity.

Further, the reflecting member 76 also functions as a supporting member (stay) that supports the nip forming member 74. By supporting the nip forming member 74 in the longitudinal direction of the fixing belt 71 by the reflecting member 76, deflection of the nip forming member 74 is suppressed, and a uniform width is formed between the fixing belt 71 and the pressure roller 72. A nip portion N is formed. The reflecting member 76 is preferably made of a highly rigid metal material such as SUS or SECC in order to ensure its function as a supporting member.

The guide member 79 is a member that is disposed inside the fixing belt 71 and guides the rotating fixing belt 71 from the inside. The guide member 79 has a guide surface 79a that curves along the inner circumferential surface of the fixing belt 71, and as the fixing belt 71 is guided along the guide surface 79a, the fixing belt 71 is largely deformed. Rotates smoothly without any movement.

In this manner, the fixing device to which the present invention is applied may be configured to heat the fixing belt 71 by transmitting the heat of the halogen heater 73 via the nip forming member 74 having good thermal conductivity.

Next, a fixing device 80 shown in FIGS. 28 and 29 is a fixing device that includes a ceramic heater (heater 83) as a heat source, like the fixing device 40 shown in FIGS. 20 and 21 described above. Specifically, the fixing device 80 shown in FIGS. 28 and 29 includes a fixing belt 81 as a first rotating body, a pressure roller 82 as a second rotating body, a heater 83 as a heat source, and a heat source. A holding member 84 as a holding member, a stay 85 as a supporting member, an arcuate guide 87 (see FIG. 29) as a rotating body holding member, a heat diffusion member 88 as a heat transfer member, and a retainer as a heat insulating member. A hot plate 89 is provided.

The fixing belt 81, pressure roller 82, heater 83, holding member 84, stay 85, and arcuate guide 87 shown in FIGS. 28 and 29 are the same as the fixing belt 41, pressure roller 42, and pressure roller 42 shown in FIGS. It basically has the same functions as the heater 43, heater holder 44, pressure stay 45, and flange 47. Note that the holding member 84 holds not only the heater 83 but also a heat diffusion member 88 and a heat retaining plate 89 in a stacked state.

The heat diffusion member 88 is made of a metal material such as stainless steel, aluminum alloy, or iron. The heat diffusion member 88 is arranged so as to be in contact with the inner peripheral surface of the fixing belt 81 , and transmits the heat generated from the heater 83 to the fixing belt 81 , and also contacts the pressure roller 82 via the fixing belt 81 . , forming a nip portion N. Furthermore, thermally conductive grease is applied between the heater 83 and the heat diffusion member 88 to improve the efficiency of heat transfer from the heater 83 to the heat diffusion member 88. On the other hand, the heat retaining plate 89 is arranged on the side opposite to the surface of the heater 83 on the heat diffusion member 88 side in order to suppress the heat of the heater 83 from being transmitted to the holding member 84 and the stay 85.

When the fixing belt 81 rotates, the fixing belt 81 slides against the heat diffusion member 88, so a lubricant is applied between the fixing belt 81 and the heat diffusion member 88 to improve sliding properties. Furthermore, a surface layer such as glass coating or hard chrome plating, which has low friction and wear resistance, is formed on the sliding surface of the heat diffusion member 88 that comes into contact with the fixing belt 81 .

Even in such a fixing device, if the temperature of the arcuate guide 87 rises due to the heat generated by the heater 83, the temperature of the lubricant adhering to the arcuate guide 87 may rise, causing FP/UFP. By applying this, it is possible to suppress the occurrence of FP/UFP.

Next, the fixing device 90 shown in FIGS. 30 and 31 includes an endless belt 91 as a first rotating body, a heating roller 96 as a heating member, a heater 93 as a heating source, and a second rotating body. The fixing device includes a pressure roller 92 as a support member, a nip forming member 94, a support member 95, a guide member 98, a lubricant application member 99 as a lubricant supply member, and a bearing 97 (see FIG. 31). .

As shown in FIG. 30, the belt 91 is wound around a heating roller 96, a nip forming member 94, and a guide member 98. A predetermined tension is applied to the belt 91 by urging the heating roller 96 away from the nip forming member 94 by a spring or the like. In this state, the pressure roller 92 is rotationally driven, and the belt 91 is driven to rotate.

The nip forming member 94 includes a pressing member 940 and a low-friction sliding sheet 941 interposed between the pressing member 940 and the inner peripheral surface of the belt 91. Since the pressing member 940 is supported by the supporting member 95, the pressing member 940 receives the pressing force of the pressing roller 92, and a nip portion N is formed.

The heater 93 is a halogen heater or the like, and is arranged inside the heating roller 96. When the heater 93 generates heat, the heating roller 96 is heated, and the heat of the heating roller 96 is transmitted to the belt 91.

The lubricant application member 99 contacts the inner circumferential surface of the belt 91 and supplies a lubricant to the inner circumferential surface of the belt 91 to improve sliding properties. As the belt 91 rotates, the lubricant supplied to the inner circumferential surface of the belt 91 is interposed between the guide member 98 and the belt 91 and between the nip forming member 94 and the belt 91, so that the lubricant is supplied to the inner peripheral surface of the belt 91. Allows smooth rotation.

Here, the heating roller 96 is generally held by a bearing 97 such as a sliding bearing or a ball bearing so as to be rotatable. The bearings 97 as such a rotating body holding member are attached to both axial ends (both longitudinal ends) of the heating roller 96, and the bearings have sliding resistance or rotational torque when the heating roller 96 rotates. A lubricant is applied to reduce the

Therefore, when the heating roller 96 is heated and the bearing 97 is affected by the heat, the temperature of the lubricant adhering to the bearing 97 increases, which may cause FP/UFP. Therefore, it is preferable to apply the present invention to the fixing device shown in FIG. 30 as well. For example, by arranging the first shielding member 31 and the second shielding member 32 as heat transfer suppressing members as described above inside the heating roller 96, a rotating body holding member that holds the heating roller 96 from the heater 93 can be used. Transfer of heat to the member (bearing 97) can be effectively suppressed. This makes it possible to reduce the number of FPs/UFPs generated, as in the above embodiment.

Further, the present invention is also applicable to a fixing device 110 having a configuration as shown in FIGS. 32 and 33.

The fixing device 110 shown in FIGS. 32 and 33 includes a fixing belt 111 as a first rotating body, a fixing roller 116, a pressure roller 112 as a second rotating body, a heater 113 as a heat source, and a nip. A pressure pad 114 as a forming member, a guide member 115, a support member 117, a temperature sensor 118 as a temperature detection member, a heat transfer member 119, and a belt holding member 122 as a rotating body holding member (see FIG. 33). ).

The fixing belt 111 shown in FIG. 32 is wound around a fixing roller 116, a pressure pad 114, a guide member 115, and a heat transfer member 119. The fixing roller 116 rotates as the pressure roller 112 rotates.

The heater 113 is a planar or plate-shaped heater such as a ceramic heater, and is provided on the heat transfer member 119. The heat transfer member 119 is a member that is interposed between the heater 113 and the fixing belt 111 and transfers the heat of the heater 113 to the fixing belt 111. Further, the heat transfer member 119 is urged by a spring 120 attached to the support member 117 so as to contact the inner circumferential surface of the fixing belt 111 .

The pressure pad 114 is urged by another spring 121 attached to the support member 117 so as to contact the inner peripheral surface of the fixing belt 111 . As a result, the pressure pad 114 is pressed against the pressure roller 112 via the fixing belt 111, and a nip portion N is formed between the fixing belt 111 and the pressure roller 112.

Guide member 115 is attached to and supported by support member 117. Further, a temperature sensor 118 is attached to the guide member 115, and the temperature of the fixing belt 111 is detected by the temperature sensor 118.

The fixing device 110 as shown in FIG. 32 is also provided with a belt holding member 122 that holds both ends of the fixing belt 111 in the longitudinal direction. There is a possibility that FP/UFP may occur due to the temperature of the lubricant increasing. Therefore, by applying the present invention to such a fixing device 110 as well, it is possible to effectively suppress the occurrence of FP/UFP as in each of the embodiments described above.

Further, the present invention is not limited to the case where it is applied to a fixing device installed in an electrophotographic image forming apparatus as described above. For example, the present invention is applicable to heating devices other than fixing devices, such as a drying device that is installed in an inkjet image forming apparatus and dries liquid such as ink applied to paper.

FIG. 39 shows one embodiment of an inkjet image forming apparatus including a drying device.

An inkjet image forming apparatus 2000 shown in FIG. 39 includes an image reading device 202, an image forming section 203, a sheet feeding device 204, a drying device 206, and a sheet discharging section 207. Further, a sheet aligning device 3000 is arranged next to the inkjet image forming apparatus 2000.

In this inkjet image forming apparatus 2000, when there is an instruction to start a printing operation, a sheet such as paper as a recording medium is fed from the sheet feeding device 204. When the sheet is conveyed to the image forming unit 203, ink is applied to the sheet from the liquid ejection head 214 of the image forming unit 203 based on the image information of the document read by the image reading device 202 or the print information instructed to print from the terminal. It is ejected and an image is formed on the sheet.

The sheet with the image formed thereon is selectively guided to either a conveyance path 222 that passes through the drying device 206 or a conveyance path 223 that does not pass through the drying device 206. When 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 guided to the sheet discharge section 207 or the sheet alignment device 3000. On the other hand, when the sheet is guided to the conveyance path 223 that does not pass through the drying device 206, the sheet is directly guided to the sheet discharge section 207 or the sheet alignment device 3000. Further, when the sheets are guided to the sheet alignment device 3000, the sheets are aligned and placed.

As shown in FIG. 40, the drying device 206 includes a heating belt 291 as a first rotating body, a heating roller 292 as a second rotating body, and a first heater 293 as a heat source for heating the heating belt 291. , a second heater 294 as a heat source that heats the heating roller 292, a nip forming member 295, a stay 296 as a supporting member, a reflecting member 297, and a rotating body holding member that rotatably holds the heating belt 291. A belt holding member 298 is provided.

The nip forming member 295 contacts the outer peripheral surface of the heating roller 292 via the heating belt 291 and forms a nip portion N between the heating belt 291 and the heating roller 292. As shown in FIG. 40, when a sheet 250 carrying an image (ink I) is conveyed to the nip portion N of the drying device 206, the sheet 250 is moved by a heating belt 291 and a heating roller 292 rotating in the direction of the arrow in the figure. is heated while being transported. This accelerates the drying of the ink I on the sheet 250.

In the drying device 206 shown in FIG. 40, the heating belt 291 is rotatably held by a pair of belt holding members 298 disposed at both ends in the longitudinal direction, so that the heating belt 291 is heated and the belt holding members If the temperature of the belt holding member 298 increases, there is a possibility that FP/UFP will occur from the lubricant adhering to the belt holding member 298. Therefore, by applying the present invention to such a drying device 206, it is possible to suppress the temperature rise of the belt holding member 298, and it becomes possible to effectively suppress the generation of FP/UFP.

Further, the present invention is also applicable to an image forming apparatus including a lamination processing apparatus as shown in FIG. 41.

The image forming apparatus 4000 shown in FIG. 41 includes a laminating processing apparatus 401, an image forming section 402 including a plurality of image forming units 411C, 411M, 411Y, and 411Bk, an exposure device 412, and a transfer device 413, and a fixing device 403. , a paper feed section 404 as a recording medium supply section.

The lamination processing apparatus 401 is a heating apparatus that heats and presses two sheets with a paper inserted between them to bond the sheet to the paper by thermocompression. Specifically, the lamination processing apparatus 401 includes a sheet supply unit 420 that supplies the sheet 450, a sheet peeling unit 430 that peels the sheet supplied from the sheet supply unit 420 into two sheets, and a sheet peeling unit 430 that peels the sheet supplied from the sheet supply unit 420 into two sheets. A heating and pressing roller 440 is provided as a rotating body that conveys the sheets while heating and pressurizing the sheets while the sheets are inserted between the sheets. Thermal pressure roller 440 is heated by a heat source such as a heater. Further, the thermal pressure roller 44 is rotatably held at both ends in the longitudinal direction by a rotating body holding member such as a pair of bearings.

In the image forming apparatus 4000 shown in FIG. 41, when paper P as a recording medium is supplied from the paper feed unit 404 to the image forming unit 402, an image is formed in the image forming unit 402, and an image is formed on the supplied paper P. The image is transferred. Then, the paper P on which the image has been transferred is conveyed to a fixing device 403, where image fixing processing is performed. Note that the image forming operation and transfer operation in the image forming unit 402 (each operation of the image forming units 411C, 411M, 411Y, 411Bk, the exposure device 412, and the transfer device 413) and the fixing operation in the fixing device 403 are the same as those in the above embodiment. Since it is basically the same as that of , the explanation will be omitted.

The paper P that has been subjected to the fixing process is then conveyed to the lamination processing apparatus 401 and inserted between the two separated sheets. Then, the paper P is heated and pressurized by the thermal pressure roller 440 while being sandwiched between the two sheets, and the sheet and the paper P are bonded by thermocompression and are discharged from the apparatus.

At this time, if the thermal pressure roller 440 is heated by a heat source such as a heater and the temperature of the bearing that supports the thermal pressure roller 440 increases, there is a possibility that FP/UFP may be generated from the lubricant adhering to the bearing. Therefore, by applying the present invention to the lamination processing apparatus 401 equipped with such a hot press roller 440, it is possible to suppress the temperature rise of the bearing that holds the hot press roller 440, and to effectively prevent the occurrence of FP/UFP. It becomes possible to suppress the

To summarize the aspects of the present invention described above, the present invention includes a heating device, a fixing device, and an image forming apparatus having at least the following configurations.

[First configuration]
The first configuration includes a rotating body that is rotatably held, a heating source that heats the rotating body, a rotating body holding member that holds both ends of the rotating body in the longitudinal direction, and a rotating body that is attached to the rotating body holding member. The heating device includes a liquid or semi-solid lubricating substance, and the temperature of the rotating body holding member is lower than the temperature at which fine particles of the liquid or semi-solid lubricating substance are generated.

[Second configuration]
The second configuration includes a rotating body that is rotatably held, a heating source that heats the rotating body, a rotating body holding member that holds both longitudinal ends of the rotating body, and a rotating body that is attached to the rotating body holding member. The heating device is equipped with a liquid or semi-solid lubricating substance, and the temperature of the rotating body holding member is 210° C. or less during continuous printing for 10 minutes.

[Third configuration]
A third configuration is a heating device in which the temperature of the rotating body holding member during 10 minutes of continuous printing is 200° C. or less in the second configuration.

[Fourth configuration]
A fourth configuration is a heating device in which the temperature of the rotating body holding member during 10 minutes of continuous printing is 194° C. or lower in the second configuration.

[Fifth configuration]
A fifth configuration is a heating device in which the temperature of the rotating body holding member during 10 minutes of continuous printing is 185° C. or less in the second configuration.

[Sixth configuration]
A sixth configuration is a heating device in the second or third configuration, in which the liquid or semisolid lubricating substance includes at least one of silicone oil and silicone grease.

[Seventh configuration]
A seventh configuration is a heating device according to the fourth or fifth configuration, wherein the liquid or semi-solid lubricating substance includes at least one of silicone oil, silicone grease, fluorine oil, and fluorine grease. be.

[Eighth configuration]
An eighth configuration is a heating device in which the heating source is arranged inside the rotating body holding member in any one of the first to seventh configurations.

[Ninth configuration]
A ninth configuration is a heating device in any one of the first to eighth configurations, including a heat transfer suppressing member that suppresses transfer of heat from the heating source to the rotating body holding member.

[Tenth configuration]
In a tenth configuration, in the ninth configuration, the heat transfer suppressing member includes a first heat transfer suppressing member disposed between the heating source and the rotating body holding member, and a first heat transfer suppressing member disposed between the heating source and the rotating body holding member. The heating device includes a second heat transfer suppressing member disposed between the transfer suppressing member and the rotating body holding member.

[Eleventh configuration]
In an eleventh configuration, in the tenth configuration, the first heat transfer suppressing member and the second heat transfer suppressing member are arranged such that at least a heat generating portion of the heating source in the longitudinal direction of the rotating body is disposed. The heating devices are arranged without contacting each other in the area.

[Twelfth configuration]
A twelfth configuration is a heating device in the tenth or eleventh configuration, in which the second heat transfer suppressing member is arranged so as not to directly contact the rotating body holding member.

[13th configuration]
In a thirteenth configuration, in any one of the tenth to twelfth configurations, the second heat transfer suppressing member is a heating device configured of a member having a thermal conductivity of 10 W/m·k or more. .

[Fourteenth configuration]
A fourteenth configuration is a heating device in the tenth or eleventh configuration, in which the second heat transfer suppressing member is made of a member having a thermal conductivity of 0.05 W/m·k or less.

[15th configuration]
A fifteenth configuration, in any one of the first to fourteenth configurations, includes a cooling device that cools the rotating body holding member, and when the number of consecutive prints reaches a predetermined number, the cooling device is turned on. This is a heating device that is operated.

[Sixteenth configuration]
A sixteenth configuration, in any one of the first to fourteenth configurations, includes a cooling device that cools the rotating body holding member and a temperature detection member that detects the temperature of the heating device, the temperature detection member The cooling device is a heating device that operates the cooling device when the detected temperature of the cooling device increases and reaches a predetermined temperature.

[Seventeenth configuration]
A seventeenth configuration is a heating device that reduces the printing speed when the number of consecutively printed sheets reaches a predetermined number in any one of the first to fourteenth configurations.

[18th configuration]
An eighteenth configuration, in any one of the first to fourteenth configurations, includes a temperature detection member that detects the temperature of the heating device, and the temperature detected by the temperature detection member increases to reach a predetermined temperature. This is a heating device that reduces the printing speed when

[19th configuration]
A nineteenth configuration is a heating device according to any one of the second to seventh configurations, in which the printing speed during the continuous printing for 10 minutes is 50 ppm or more.

[Twentieth configuration]
A 20th configuration is a fixing device that heats a recording medium carrying an unfixed image using the heating device of any one of the 1st to 19th configurations, and fixes the unfixed image on the recording medium. be.

[21st configuration]
A twenty-first configuration is an image forming apparatus including the heating device of any one of the first to nineteenth configurations or the fixing device of the twentieth configuration.

20 Fixing device (heating device)
21 Fixing belt (first rotating body)
22 Pressure roller (second rotating body)
23 Heater (heating source)
27 Belt holding member (rotating body holding member)
31 First shielding member (first heat transfer suppressing member)
32 Second shielding member (second heat transfer suppressing member)
36 Cooling device 100 Image forming device H Heat generating section N Nip section X Longitudinal direction

Japanese Patent Application Publication No. 2013-164453

Claims (21)

a rotating body rotatably held;
a heating source that heats the rotating body;
a rotating body holding member that holds both longitudinal ends of the rotating body;
comprising a liquid or semi-solid lubricating substance that adheres to the rotating body holding member,
A heating device characterized in that the temperature of the rotating body holding member is lower than the generation temperature of the fine particles of the liquid or semi-solid lubricating substance. a rotating body rotatably held;
a heating source that heats the rotating body;
a rotating body holding member that holds both longitudinal ends of the rotating body;
comprising a liquid or semi-solid lubricating substance that adheres to the rotating body holding member,
A heating device characterized in that the temperature of the rotating body holding member during 10 minutes of continuous printing is 210° C. or less. The heating device according to claim 2, wherein the temperature of the rotating body holding member during continuous printing for 10 minutes is 200° C. or less. The heating device according to claim 2, wherein the temperature of the rotating body holding member during continuous printing for 10 minutes is 194° C. or less. The heating device according to claim 2, wherein the temperature of the rotating body holding member during continuous printing for 10 minutes is 185° C. or less. The heating device according to claim 2 or 3, wherein the liquid or semi-solid lubricating substance contains at least one of silicone oil and silicone grease. 6. The heating device according to claim 4, wherein the liquid or semi-solid lubricating substance contains at least one of silicone oil, silicone grease, fluorine oil, and fluorine grease. The heating device according to any one of claims 1 to 5, wherein the heating source is arranged inside the rotating body holding member. The heating device according to any one of claims 1 to 5, further comprising a heat transfer suppressing member that suppresses transfer of heat from the heat source to the rotating body holding member. The heat transfer suppressing member includes a first heat transfer suppressing member disposed between the heat source and the rotating body holding member, and a first heat transfer suppressing member disposed between the first heat transfer suppressing member and the rotating body holding member. The heating device according to claim 9, further comprising a second heat transfer suppressing member disposed. 10. The first heat transfer suppressing member and the second heat transfer suppressing member are disposed in a non-contact manner with each other at least in a range in which a heat generating portion of the heat source is disposed in the longitudinal direction of the rotating body. The heating device described in . The heating device according to claim 10, wherein the second heat transfer suppressing member is arranged so as not to directly contact the rotating body holding member. The heating device according to claim 10, wherein the second heat transfer suppressing member is a member having a thermal conductivity of 10 W/m·k or more. The heating device according to claim 10, wherein the second heat transfer suppressing member is a member having a thermal conductivity of 0.05 W/m·k or less. comprising a cooling device that cools the rotating body holding member,
The heating device according to any one of claims 1 to 5, wherein the cooling device is operated when the number of consecutively printed sheets reaches a predetermined number. a cooling device that cools the rotating body holding member;
comprising a temperature detection member that detects the temperature of the heating device,
The heating device according to any one of claims 1 to 5, wherein the cooling device is operated when the temperature detected by the temperature detection member increases and reaches a predetermined temperature. The heating device according to any one of claims 1 to 5, wherein the printing speed is reduced when the number of consecutively printed sheets reaches a predetermined number. comprising a temperature detection member that detects the temperature of the heating device,
The heating device according to any one of claims 1 to 5, wherein the printing speed is reduced when the temperature detected by the temperature detection member increases and reaches a predetermined temperature. The heating device according to claim 2, wherein the printing speed during the 10 minutes of continuous printing is 50 ppm or more. A fixing device, characterized in that the heating device according to any one of claims 1 to 5 is used to heat a recording medium carrying an unfixed image to fix the unfixed image on the recording medium. An image forming apparatus comprising the heating device according to claim 1 .

Images