JP2023165389A - Heating device, fixation device, and image formation device - Google Patents

Abstract

[Problem] To suppress the generation of ultrafine particles.
A heating device 20 includes a rotating body 21 that is rotatably held, a heating source 23 that heats the rotating body 21, a rotating body holding member 27 that holds both longitudinal ends of the rotating body 21, and a rotating body holding member 27 that holds both longitudinal ends of the rotating body 21. The silicone oil or silicone grease that adheres to the body holding member 27 is provided, and the concentration of 12-mer or more and 17-mer or less siloxane contained in the silicone oil or silicone grease is 1250 ppm or less.
[Selection diagram] 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.

Some fixing devices include sliding 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. In such a fixing device, a lubricating substance such as oil or grease (hereinafter referred to as a "lubricant") is generally used to reduce the sliding resistance generated between the sliding member and the rotating body. It is used. This lubricating substance 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, it is necessary to pass various tests, but the test for ultra-fine particles is particularly demanding. Specifically, the number of ultrafine particles obtained when measuring ultrafine particles of 5.6 nm to 560 nm generated from an image forming apparatus using a particle counter FMPS (Fast Mobility Particle Sizer) is 3.5. ×10 ¹¹ pieces/10 minutes or less is required, and it is expected that the standard value will become even stricter in the future. In this case, the number of ultrafine particles does not depend on the type or state of the substance forming the ultrafine particles, for example, there is no distinction between inorganic/organic matter, and there is no distinction between solid/liquid (mist). All that matters is the size and number of ultrafine particles.

Ultrafine particles are said to be generated from various components that make up an image forming device, but starting only the fixing device significantly increases the amount of ultrafine particles generated. It is known that this is the main cause of ultrafine particles. In fact, when the aforementioned lubricant is heated to a high temperature, ultrafine particles are detected, so the lubricant is one of the sources of ultrafine particles. 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 ultrafine particles. There is a need to prevent lubricants from being exposed to high-temperature environments and to suppress the generation of ultrafine particles from image forming apparatuses.

The present invention aims to suppress ultrafine particles discharged from heating devices and image forming devices.

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 silicone oil or silicone grease that adheres to the rotating body holding member, and the concentration of siloxane of 12-mer or more and 17-mer or less contained in the silicone oil or silicone grease is 1250 ppm or less. shall be.

According to the present invention, generation of ultrafine 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. 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. 3 is a diagram showing the relationship between the temperature of a lubricant and the concentration of ultrafine particles generated. FIG. 3 is a perspective view of a sample container. FIG. 3 is a diagram showing the relationship between printing speed and generation speed of ultrafine particles. FIG. 3 is a cross-sectional view showing the configuration of another fixing device to which the present invention is applicable. 9 is an exploded perspective view of the fixing device shown in FIG. 8. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 11 is an exploded perspective view of the fixing device shown in FIG. 10. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 13 is an exploded perspective view of the fixing device shown in FIG. 12. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. FIG. 15 is a cross-sectional view of the fixing device shown in FIG. 14 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. 17 is an exploded perspective view of the fixing device shown in FIG. 16. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 19 is a sectional view showing a holding structure for the pressure roller shown in FIG. 18. FIG. FIG. 7 is a sectional view showing the configuration of yet another fixing device to which the present invention is applicable. 21 is a perspective view of the fixing device shown in FIG. 20. FIG. 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, contacts the pressure roller 22 via the fixing belt 21, and forms a nip portion N between the fixing belt 21 and 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.

As the belt holding member 27, resin materials called "super engineering plastics" such as polyphenylene sulfide, polyether ether ketone, polyarylate, liquid crystal polymer, polyimide, polybenzimidazole, and polybutylene naphthalate are used. Among these, liquid crystal polymers are preferred from the viewpoints of processability and heat resistance. Further, as the belt holding member 27, it is more preferable that the belt holding member 27 is formed by mixing glass fiber with the above-mentioned super engineering plastic because it can prevent the belt holding member 27 from deforming due to temperature changes.

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.

By the way, in JP-A-8-262903, a rotatable heat fixing roll, an endless belt (fixing belt) that contacts the heat fixing roll, and a press contact with the heat fixing roll (pressure roller) via the endless belt are disclosed. A fusing device is described that includes a pressure pad (nip forming member). The pressure pad is disposed inside the endless belt in a non-rotating state and presses the endless belt against the heat fixing roll. As a result, the surface of the heat-fixing roll is elastically deformed, and a belt nip is formed between the endless belt and the heat-fixing roll, through which the recording sheet (recording medium or recording material holding a toner image) is passed. According to the configuration of this image fixing device, it is possible to reduce heat loss in the belt nip, and also to prevent a speed difference between the recording sheet and the heat fixing roll and disturbance of the toner image due to air or water vapor in the belt nip. has been done.

However, if the coefficient of friction between the inner circumferential surface of the endless belt and the pressure pad (nip forming member) is large, the driving torque of the heat fixing roll will be large, and the stress acting on the gear receiving section will be large, causing damage to the gear and core. There is a possibility that this may occur. In addition, if the frictional force between the endless belt and the pressure pad is too large to ignore compared to the driving force of the endless belt by the heat-fixing roll, slippage will occur between the heat-fixing roll and the endless belt, causing recording. There is also a possibility that the unfixed toner image on the sheet may be shifted.

In order to solve these problems, Japanese Patent Application Laid-Open No. 10-213984 proposes a fixing device in which modified silicone oil is interposed as a lubricant between a pressure pad and an endless belt. There is. This makes it possible to ensure stable running performance (rotation performance) of the endless belt without reducing the releasability of the recording sheet from the heat-fixing roll.

However, in the fixing device described in JP-A-10-213984, the friction coefficient of the low-friction sheet is only reduced to make the surface of the pressure pad on which the endless belt slides a low-friction surface. No consideration is given to the surface wetting properties of modified silicone oil on low-friction sheets or endless belts. Therefore, there is a problem that it is difficult to stably hold the modified silicone oil, and maintenance is difficult.

Therefore, in order to solve this problem, Japanese Patent Application Laid-Open No. 2010-211220 discloses that a pressure pad (pressing A structure has been proposed for use as a sliding member on a sheet interposed between an endless belt (resin film tubular body) and an endless belt (resin film tubular body). Furthermore, in another Japanese Patent Application Publication No. 2001-249558, a fixing device uses a fluororesin treated to make it lipophilic on the sliding surface of a pressure pad (pressing member), or uses a lipophilic agent in combination with the fluororesin. is proposed. This improves the wettability to the lubricant and makes it difficult for oil to run out, so it is possible to achieve stable sliding performance and maintain good quality and fixability of fixed images.

The fixing device described above, which uses a lubricant such as silicone oil between the sliding surface of the nip forming member (pressure pad) and the inner peripheral surface of the fixing belt (endless belt), is highly energy efficient and energy saving. It has the advantage of being easy to implement. For this reason, such fixing devices are used in many image forming apparatuses.

Here, it is known that ultrafine particles generated from an image forming apparatus are generated from various members constituting the image forming apparatus. Among these, it is known that the fixing device is the main cause of the generation of ultrafine particles because the amount of ultrafine particles generated increases significantly when only the fixing device is driven. It is also known that toner is involved in the generation of ultrafine particles, since the generation of ultrafine particles decreases when an image with a low image area is printed.

Note that in this specification, "ultrafine particles" refer to fine particles and ultrafine particles (sometimes referred to as "FP/UFP") measured under measurement conditions for examining the relationship shown in FIG. 5, which will be described later. , meaning particles with a particle size of 5.6 nm to 560 nm.

In addition, detailed analysis has been conducted on the components of ultrafine particles, and in the 34th Aerosol Science and Technology Research Conference Abstracts 211-212 (2017), in addition to toner-derived paraffin and higher alcohols, It has been reported that a cyclic siloxane having a 12-mer (D12) or more and a 17-mer (D17) or less is a component of ultrafine particles.

Such 12- to 17-mer cyclic siloxanes are usually present as impurities in silicone rubber or silicone oil. For example, Japanese Patent No. 4985803 describes that siloxane as ultrafine particles is generated from silicone rubber of a roller used in a fixing device. However, it was not clear from what specifically the 12-17-mer cyclic siloxane was generated.

Further, the number of ultrafine particles generated from the fixing device tends to increase as the fixing belt is heated and the temperature of the fixing belt becomes higher. As a countermeasure against the increase in ultrafine particles caused by the rise in temperature of the fixing belt, there is a method of lowering the melting point of the toner. By lowering the melting point of the toner, the temperature of the fixing belt can be set low, thereby suppressing the generation of ultrafine particles. Further, in the case of conditions where the temperature of the fixing belt can be set low, a low-cost silicone oil from which low-molecular-weight siloxane is not removed can be used as the silicone oil interposed between the pressing member and the fixing belt.

However, due to the demand for increased printing speed, when the printing speed is increased, ultrafine particles are generated even though the surface temperature of the fixing belt is not changed. This is thought to be due to the fact that when the print speed is increased, the output of the heater that heats the fixing belt increases in order to maintain the temperature of the fixing belt constant. That is, it is considered that the silicone oil in the fixing belt is directly heated by a high-output heater, so that the temperature of the silicone oil tends to rise, and ultrafine particles are generated from the silicone oil.

In order to suppress the generation of such ultrafine particles originating from silicone oil in the fixing belt, for example, in Japanese Patent No. 6213313, the sliding contact outer surface of the nip forming member (pressing member) and the fixing belt (endless belt ) has been proposed to reduce the content of 11 to 17-mer siloxane contained in the silicone oil between the sliding surface and the sliding surface to 2000 ppm or less.

That is, in the above-mentioned Japanese Patent No. 6213313, it is considered that the silicone oil interposed between the nip forming member and the fixing belt is the source of the ultrafine particles. Therefore, in order to verify that most of the ultrafine particles generated from the fixing device originate from the silicone oil interposed between the fixing belt and the nip forming member, we A fixing process was carried out by applying a silicone oil containing a low amount of 11 to 17-mer siloxane between the two. However, the generation of ultrafine particles could not be effectively suppressed. Furthermore, when a silicone oil with an extremely low content of tri- to 20-mer cyclic siloxane, as disclosed in Japanese Patent No. 5153251, is interposed between the fixing belt and the nip forming member, ultrafine particles It was not possible to effectively suppress the occurrence of

Therefore, the present inventors conducted a detailed examination to determine from which part of the fixing device many ultrafine particles were generated, and found that many ultrafine particles were generated near the ends of the fixing belt. At the beginning of the verification, it was thought that the cause of the generation of ultrafine particles was silicone oil interposed between the fixing belt and the nip forming member, so in the above verification test to identify the cause of the generation of ultrafine particles, No consideration was given to silicone oil interposed between the outer peripheral surface of the belt holding member and the inner peripheral surface of the fixing belt. In other words, the amount of silicone oil that adheres to the belt holding member is overwhelmingly smaller than the amount of silicone oil that is interposed between the fixing belt and the nip forming member, and the belt holding member is not connected to the heater that heats the fixing belt. At the beginning of the verification, it was thought that the silicone oil on the belt holding member had little to do with the generation of ultrafine particles.

However, the inventors of the present invention discovered that when the silicone oil adhering to the belt holding member was wiped off and a blank image to which toner did not adhere was printed, the amount of ultrafine particles generated was significantly reduced. From this, it was found that the main source of ultrafine particles generated from the fixing device was the silicone oil interposed between the belt holding member and the fixing belt.

In order to effectively suppress the generation of ultrafine particles, it is effective not to use a lubricant such as silicone oil between the belt holding member and the fixing belt. However, in this case, smooth sliding of the fixing belt with respect to the belt holding member may not be achieved, and the ends of the fixing belt may be damaged, which may shorten the product life of the fixing device. In particular, when the material of the belt holding member includes glass fibers, there is a risk that the inner peripheral surface of the fixing belt may be damaged by the glass fibers exposed on the surface of the belt holding member. Therefore, in order to suppress damage to the inner circumferential surface of the fixing belt, it is preferable to interpose a lubricant such as silicone oil between the outer circumferential surface of the belt holding member and the inner circumferential surface of the fixing belt.

In view of such circumstances, in the present invention, in a structure in which a lubricant is interposed between a rotating body such as a fixing belt and a rotating body holding member that holds the same, generation of ultrafine particles derived from the lubricant is prevented. The purpose is to suppress. Hereinafter, a method for suppressing the generation of ultrafine particles will be described using an embodiment of the present invention as an example.

As described above, in the fixing device 20 according to the present embodiment shown in FIGS. 1 to 3, when the fixing belt 21 rotates, the fixing belt 21 moves against the nip forming member 24 disposed inside the fixing belt 21. A lubricant is applied between the fixing belt 21 and the nip forming member 24 so that the fixing belt 21 and the nip forming member 24 can slide. This reduces the sliding resistance generated between the fixing belt 21 and the nip forming member 24, so that smooth rotation of the fixing belt 21 can be maintained and wear of the fixing belt 21 can be suppressed. As the lubricant, silicone oil, silicone grease, fluorine grease, fluorine oil, etc. are generally used. Further, 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, in the fixing device 20 according to the present embodiment, since a pair of belt holding members 27 that rotatably hold both ends of the fixing belt 21 in the longitudinal direction are provided, each belt holding member 27 and the fixing belt 21 The above-mentioned lubricant is also present between the two for the purpose of reducing sliding resistance. In particular, when the belt holding member 27 contains glass fibers, the glass fibers exposed on the surface may damage the fixing belt 21, inhibit rotation of the fixing belt 21, and deteriorate image quality. It is preferable that a lubricant such as silicone grease, fluorine grease, or fluorine oil be interposed between the outer circumferential surface of the belt holding member 27 and the inner circumferential surface of the fixing belt 21 .

In this way, in a configuration including sliding members such as the nip forming member 24 and the belt holding member 27 that slide relative to the rotating fixing belt 21, the sliding properties of the fixing belt 21 are improved. Therefore, lubricants such as silicone oil, silicone grease, fluorine grease, and fluorine oil are generally used. Among these lubricants, silicone oil and silicone grease are particularly suitable for use as lubricants because they have appropriate heat resistance and are cheaper than fluorine oil and fluorine grease.

Generally, the surface temperature of the fixing belt 21 at the portion that comes into contact with the paper is strictly controlled because it has a large effect on image quality. This is the same in the fixing device according to this embodiment, and when the paper contacts the fixing belt 21 when fixing an unfixed image on the paper, heat is transferred from the fixing belt 21 to the paper. Therefore, heat is applied from the heater 23 to the fixing belt 21 so as to supplement the consumed heat to the fixing belt 21. On the other hand, in the portions of the fixing belt 21 where the paper does not come in contact with each other, heat is less likely to be consumed when paper passes, so when a plurality of papers are passed continuously, the fixing belt 21 tends to accumulate heat and rise in temperature. be.

Therefore, as shown in FIG. 4, the temperature of the fixing belt 21 increases in the area (non-paper passing area) outside the maximum paper passing area (maximum recording medium passing area) W where the largest paper passes. Therefore, when the temperature of the fixing belt 21 rises, the temperature of the belt holding member 27 that holds the portion where the temperature rises also rises, and the temperature of the silicone oil or silicone grease that adheres to the belt holding member 27 also rises. In particular, in a configuration in which the heat generating portion H of the heater 23 extends to the outside of the maximum paper passing area W as shown in FIG. As the temperature of the holding member 27 increases, the temperature of the silicone oil or silicone grease also increases significantly.

As a result, the temperature of the silicone oil or silicone grease interposed between the belt holding member 27 and the fixing belt 21 increases, and the siloxane containing 12-mer or more and 17-mer or less contained in the silicone oil or silicone grease evaporates. , there is a possibility that ultrafine particles may be generated.

Figure 5 shows the relationship between the hot plate temperature and the concentration of FP/UFP (number of FP/UFP per 1 ^cm3 ) in the measurement atmosphere when general silicone oil used for the belt holding member 27 is heated with a hot plate. It is a graph showing a relationship.

In this test to investigate the relationship shown in FIG. 5, silicone oil 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. 6, 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 a 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). The sample volume (silicone oil volume) was 36 μl. In Figure 5, the horizontal axis shows the temperature of the hot plate, 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 expressed as the temperature of the silicone oil. Regarded as temperature.

As shown in FIG. 5, FP/UFP began to be generated when the temperature of the silicone oil reached 200°C, and the number concentration of FP/UFP rapidly increased when the temperature exceeded 210°C. At temperatures above 210° C. where the number concentration rapidly increases, the number concentration of FP/UFP in the chamber reached 4000 pieces/cm ³ or more.

Thus, in commonly used silicone oils, when the temperature reaches 200° C., siloxanes containing 12-mer or more and 17-mer or less contained in the silicone oil volatilize, generating FP/UFP. Although not shown in FIG. 5, FP/UFP occurs in silicone grease when the temperature reaches 200° C., similarly to silicone oil.

For this reason, in order to suppress the generation of ultrafine particles in a fixing device where the temperature of the belt holding member 27 is 200°C or higher during the fixing process (during continuous sheet feeding), it is necessary to It can be said that it is essential to lower the concentration of 12-17-mer (12-mer or more and 17-mer or less) siloxane in the silicone oil or silicone grease that adheres to the belt holding member 27, which is a contributing factor. Therefore, in the present invention, the concentration of 12-17-mer siloxane in the silicone oil or silicone grease that adheres to the belt holding member 27 is set to be (0 ppm or more) and 1250 ppm or less. This makes it possible to effectively suppress the generation of ultrafine particles even in a fixing device where the temperature of the belt holding member 27 reaches 200° C. or higher during the fixing process. Furthermore, in order to further suppress the generation of ultrafine particles, it is preferable that the concentration of 12-17-mer siloxane in the silicone oil or silicone grease adhering to the belt holding member 27 is 500 ppm or less.

An example of silicone oil used in the present invention will be explained below.

In the present invention, as an example of the silicone oil interposed between the belt holding member 27 and the fixing belt 21, silicone oil made of organopolysiloxane is used. Organopolysiloxane is, for example, a compound represented by the following general composition formula (1), or a diorganopolysiloxane whose main chain is R _b SiO _2/2 (R _b represents the same meaning as R _a ). Examples include compounds consisting of repeating siloxane units.

R _a SiO _(4-a)/2 ...(1)

In the above formula (1), R _a represents an optionally substituted monovalent hydrocarbon group having 1 to 20 carbon atoms, and the value of a is an arbitrary number from 1 to 2.5. Specific examples of the monovalent hydrocarbon group which may have a substituent having 1 to 20 carbon atoms in R _a include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert- Alkyl groups such as butyl group, pentyl group, hexyl group, heptyl group, octyl group, decyl group; cycloalkyl group such as cyclohexyl group, cycloheptyl group; vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, etc. Examples include alkenyl groups, phenyl groups, aryl groups such as tolyl groups, and aralkyl groups such as benzyl groups and phenylethyl groups. Among these, methyl groups are particularly preferred.

In addition, when the monovalent hydrocarbon group has a substituent (modified silicone oil), the substituent includes an amino group, an epoxy group, a carboxyl group, a carboxylic acid group, etc. Examples include those substituted with a nol group, methacrylic group, acrylic group, mercapto group, phenol group, hydroxyl group, polyether group, alkoxy group, and halogen atoms such as fluorine, chlorine, and bromine.

Among the various silicone oils mentioned above, dimethyl silicone oil is particularly preferably used because it can further suppress the generation of ultrafine particles. However, in order to suppress the generation of ultrafine particles in the silicone oil used in the present invention, the concentration of 12-17-mer siloxane among the molecules constituting the organopolysiloxane is 1250 ppm or less, more preferably 500 ppm or less. It is.

Methods for reducing the concentration of 12-17-mer siloxane to 1250 ppm or less include heating and depressurizing, purification by solvent extraction with alcohols such as methanol, ethanol, and butanol, and purification using a mixed solvent of toluene and acetone as an eluent. An example is purification by chromatography.

The present invention is particularly effective when using a silicone oil whose viscosity at the fixing temperature is 10,000 cSt (10,000 mm ² /s) or less, particularly 5,000 cSt (5,000 mm ² /s) or less.

Moreover, silicone grease may be used instead of silicone oil on the rotating body holding member (belt holding member 27) according to the present invention. The silicone grease used is one obtained by using the above-mentioned silicone oil as a base oil and making it semi-solid with a thickener such as metal soap or polyfluoroethylene.

Next, the present invention will be described in more detail by citing Examples and Comparative Examples of the present invention. Note that the present invention is not limited to the examples described below.

<Silicone oil adjustment 1>
First, the silicone oil used in the Examples and Comparative Examples shown in Table 1 below will be explained. Silicone oil 1 in Table 1 is commercially available dimethyl silicone oil (silicone oil 1) [kinematic viscosity (25°C): 104 mm ² /s], and other silicone oils 2, 3, and 4 are silicone oil 1. These were obtained by vacuum drying at 195°C, 215°C, and 230°C. The concentrations of the 12- to 17-mer cyclic siloxane contained in these silicone oils 1 to 4 are different from each other as shown in Table 1 below (see the parentheses next to silicone oils 1 to 4 in Table 1). The concentration of cyclic siloxane is a value measured by gas chromatography under the following conditions.
[Measurement condition]
Column: ZB-5 L=30m, ID=0.25mm, Film=0.25μm
Column temperature increase: 40°C (holding 1 min) ~ 20°C/min ~ 320°C (holding 35 min)
Carrier gas: He
Ionization method: EI method (70eV)
Measurement mode: Total ion chromatogram (TIC)

<Example 1>
In Example 1, a fixing device having the configuration shown in FIGS. 2 and 3 was used, and the belt holding member 27 included in this fixing device was made of a liquid crystal polymer containing glass fibers, carbon black, and glass beads. . Further, the sliding sheet 30 was impregnated with the silicone oil 1, and the outer peripheral surface of the belt holding member 27 was coated with the silicone oil 3. Then, the fixing belt 21 is rotated once, and each silicone oil is applied to the sliding portion of the sliding sheet 30 that contacts the inner circumferential surface of the fixing belt 21 and the inner circumferential surface of the fixing belt 21 that contacts the belt holding member 27. I let it happen. The fixing device configured as described above was installed in an image forming apparatus with a printing speed of 50 ppm (Page Par Minutes), and continuous printing was performed for 10 minutes at a certification laboratory for the German environmental label "Blue Angel Mark". As a result, in Example 1, as shown in Table 1 above, the generation rate of ultrafine particles during 10 minutes of continuous printing was 3.0 × 10 ¹¹ pieces/10 minutes, and the “Blue Angel Mark” This was below the certification standard of 3.5×10 ¹¹ pieces/10 minutes. Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 203°C. Furthermore, when printing was carried out in an indoor environment and a total of 50,000 images were formed, no abnormality was found at the end of the fixing belt 21.

<Example 2>
In Example 2, the silicone oil 4 described above was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as Example 1 above. Then, in the same manner as in Example 1, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 1 above, in Example 2, the generation rate of ultrafine particles during 10 minutes of continuous printing was 2.4 × 10 ¹¹ particles/10 minutes, which resulted in a "Blue Angel Mark". This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 203° C., and no abnormality was observed at the end of the fixing belt 21 after forming 50,000 images.

<Example 3>
In Example 3, the silicone oil 2 described above was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as Example 1 above. Then, in the same manner as in Example 1, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 1 above, in Example 3, the generation rate of ultrafine particles during 10 minutes of continuous printing was 3.5 × 10 ¹¹ particles/10 minutes, and the “Blue Angel Mark” This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 203° C., and no abnormality was observed at the end of the fixing belt 21 after forming 50,000 images.

<Comparative example 1>
In Comparative Example 1, the silicone oil 1 described above was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as Example 1 above. Then, in the same manner as in Example 1, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 1 above, in Comparative Example 1, the generation rate of ultrafine particles during 10 minutes of continuous printing was 5.9 x 10 ¹¹ particles/10 minutes, which was the result of the "Blue Angel Mark". The certification standard (3.5×10 ¹¹ pieces/10 minutes) was exceeded. Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 203° C., and no abnormality was observed at the end of the fixing belt 21 after forming 50,000 images.

<Comparative example 2>
Comparative Example 2 was the same as Example 1 except that silicone oil was not applied to the outer peripheral surface of the belt holding member 27. Then, in the same manner as in Example 1, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 1 above, in Comparative Example 2, the generation rate of ultrafine particles during 10 minutes of continuous printing was 1.6 x 10 ¹¹ particles/10 minutes, which resulted in a "Blue Angel Mark". This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 205° C., and many scratches were observed at the end of the fixing belt 21 after forming images on 50,000 sheets.

<Silicone oil adjustment 2>
Next, silicone oils used in Examples and Comparative Examples shown in Table 2 below will be explained. Silicone oils 5, 6, and 7 in Table 2 are silicone oils 5, 6, and 7, which are obtained by mixing the above silicone oil 1 with ethanol, stirring it, leaving it to stand, separating the silicone oil and ethanol, and then heating the extracted silicone oil at 180°C, 200°C, It was obtained by vacuum drying at 220°C. Moreover, silicone oil 8 in Table 2 is obtained by refining the above-mentioned silicone oil 1 by liquid chromatography (LC) under the following conditions.
[Generation conditions]
Equipment: Hi-Sep LC prep type A (manufactured by Soken Chemical Co., Ltd.)
Column: 20mmΦ x 250mm (diameter x length)
Filler: ODS-W (manufactured by Soken Chemical Co., Ltd.) 15/30μm
Eluent: Stepwise acetone/toluene Washing solution: 100% toluene
Detection: RI (differential refractometer), Range64
Flow rate: 13ml/min (linear speed, 4.12cm/min)
Temperature: Room temperature (25℃)
Sample: Dimethylpolysiloxane/[Solvent, acetone + toluene (mixing ratio 10/4)]

<Example 4>
In Example 4, the silicone oil 5 was used as the silicone oil impregnated into the sliding sheet 30 and the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as Example 1 above. Then, the fixing device of Example 4 was installed in an image forming apparatus with a printing speed of 60 ppm (Page Par Minutes), and continuous printing was performed for 10 minutes at a certification laboratory for the German environmental label "Blue Angel Mark." As a result, in Example 4, as shown in Table 2 above, the generation rate of ultrafine particles during 10 minutes of continuous printing was 3.0 × 10 ¹¹ pieces/10 minutes, and the “Blue Angel Mark” This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 212°C.

<Example 5>
In Example 5, the silicone oil 6 described above was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as in Example 4 above. Then, in the same manner as in Example 4, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 2 above, in Example 5, the generation rate of ultrafine particles during 10 minutes of continuous printing was 2.6 × 10 ¹¹ particles/10 minutes, which resulted in the formation of the "Blue Angel Mark". This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 212°C.

<Example 6>
In Example 6, the silicone oil 7 described above was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as in Example 4 above. Then, in the same manner as in Example 4, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 2 above, in Example 6, the generation rate of ultrafine particles during 10 minutes of continuous printing was 1.5 × 10 ¹¹ particles/10 minutes, which resulted in the formation of the "Blue Angel Mark". This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 212°C.

<Example 7>
In Example 7, the silicone oil 8 described above was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. The rest is the same as in Example 4 above. Then, in the same manner as in Example 4, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 2 above, in Example 7, the generation rate of ultrafine particles during 10 minutes of continuous printing was 0.8 × 10 ¹¹ particles/10 minutes, and the “Blue Angel Mark” This was below the certification standard (3.5×10 ¹¹ pieces/10 minutes). Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 212°C.

<Comparative example 3>
In Comparative Example 3, the above silicone oil 8 was used as the silicone oil impregnated into the sliding sheet 30, and the silicone oil 1 was used as the silicone oil applied to the outer peripheral surface of the belt holding member 27. This is the same as in Example 4. Then, in the same manner as in Example 4, image formation was performed at a certified testing laboratory, and the generation rate of ultrafine particles was measured. As a result, as shown in Table 2 above, in Comparative Example 3, the generation rate of ultrafine particles during 10 minutes of continuous printing was 6.6 x 10 ¹¹ particles/10 minutes, which resulted in a "Blue Angel Mark". The certification standard (3.5×10 ¹¹ pieces/10 minutes) was exceeded. Further, the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing was 212°C.

As described above, according to the results in Tables 1 and 2, in Examples 1 to 7 in which the concentration of 12-17-mer cyclic siloxane contained in the silicone oil was 1250 ppm or less, continuous print 10 The generation rate of ultrafine particles per minute was below the "Blue Angel Mark" certification standard (3.5 x 10 ¹¹ particles/10 minutes). On the other hand, in Comparative Examples 1 and 3, in which the concentration of 12-17-mer cyclic siloxane contained in the silicone oil was higher than 1250 ppm, the generation rate of ultrafine particles during 10 minutes of continuous printing was The results exceeded the "Blue Angel Mark" certification standard (3.5 x 10 ¹¹ pieces/10 minutes). From this, by reducing the concentration of 12-17-mer siloxane in the silicone oil adhering to the belt holding member 27 to 1250 ppm or less, it is possible to effectively suppress the generation of ultrafine particles during 10 minutes of continuous printing. It can be said. Preferably, if the concentration of the 12-17-mer siloxane is 500 ppm or less, the generation of ultrafine particles can be further suppressed. Furthermore, since 12-17-mer siloxane is a source of ultrafine particles, the less 12-17-mer siloxane contained in silicone oil, the fewer ultrafine particles there will be. The amount of 12-17-mer siloxane contained in silicone oil can be reduced to 0 ppm using existing purification methods. For example, by repeating the purification by liquid chromatography (L C ) used in the purification of silicone oil 8 three times, the concentration of 12-17-mer siloxane in the silicone oil can be reduced to 0 ppm. Furthermore, when image formation was performed in the same manner by replacing silicone oil with a 12-17-mer siloxane concentration of 0 ppm in place of silicone oil 8 in Example 7, ultrafine particles were observed during continuous printing for 10 minutes. The generation rate was 0.8×10 ¹¹ pieces/10 minutes, which was below the “Blue Angel Mark” certification standard (3.5×10 ¹¹ pieces/10 minutes). Therefore, in the present invention, the concentration of 12-17-mer siloxane contained in silicone oil is set to 0 ppm or more and 1250 ppm or less.

In addition, in Comparative Example 2 in Table 1, many scratches occurred at the end of the fixing belt 21, so in order to suppress the occurrence of such scratches, the belt holding member 27 and the fixing belt 21 should be It can be said that it is important to interpose a lubricant such as silicone oil in between. On the other hand, in Examples 1 to 7, since silicone oil was interposed between the belt holding member 27 and the fixing belt 21, no abnormality occurred at the end of the fixing belt 21. Therefore, in the cases of Examples 1 to 7, it can be said that damage to the ends of the fixing belt 21 can be suppressed, the life of the fixing device can be extended, and the generation of ultrafine particles can also be suppressed. As described above, according to the present invention, even in a configuration in which silicone oil is interposed between the belt holding member 27 and the fixing belt 21 in order to suppress damage to the fixing belt 21, generation of ultrafine particles can be prevented. Since this can be suppressed, it is possible to provide a fixing device that has a long life and generates a small amount of ultrafine particles.

Generally, the higher the productivity of image formation (the faster the printing speed), the greater the amount of heat supplied from the heater 23 to the fixing belt 21, and therefore the temperature of the belt holding member 27 tends to become higher. For example, when forming images on A4 size paper at a rate of 50 sheets or more per minute (50 ppm or more), the temperature of the belt holding member 27 is likely to be 200° C. or more. Therefore, in such an image forming apparatus, the temperature of the silicone oil or silicone grease adhering to the belt holding member 27 may exceed 200° C., which is the ultrafine particle generation temperature, and a large number of ultrafine particles may be generated. There is.

That is, the temperature rise of the belt holding member 27, which causes the generation of ultrafine particles, becomes more pronounced in image forming apparatuses that pass a large number of sheets per unit time. Great effects can be expected when applied to equipment. According to FIG. 7, which shows the relationship between print speed and FP/UFP generation rate, the number of FP/UFP 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.

In addition, if the maximum temperature of the belt holding member 27 reaches within the range of 200°C or more and 240°C or less during 10 minutes of continuous printing, the temperature of the silicone oil or silicone grease is 200°C, which is the ultrafine particle generation temperature. There is a high possibility that it will be more than that. Therefore, the present invention can be expected to have greater effects when applied to a fixing device in which the maximum temperature of the belt holding member 27 during 10 minutes of continuous printing is in the range of 200° C. or higher and 240° C. or lower.

Here, the timing at which the maximum temperature of the belt holding member 27 reaches a range of 200° C. or more and 240° C. or less is during 10 minutes of continuous printing is because image forming apparatuses in the market are generally used for several minutes. This is because continuous printing for 5 minutes or more is rarely performed. Therefore, in the present invention, it is sufficient to suppress the generation of ultrafine particles during at least 10 minutes of continuous printing.

Note that the above-mentioned "maximum temperature of the belt holding member during 10 minutes of continuous printing" means the maximum 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 ultrafine particle standards.

Although the embodiments of the present invention have been described above, the present invention is not limited to the fixing devices having the configurations shown in FIGS. 2 to 4, but is also applicable to fixing devices having other 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. 8 and 9 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. 9) as a rotating body holding member.

The functions and configurations of the fixing belt 41 and the pressure roller 42 shown in FIG. 8 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 rises, and the 12-17-mer siloxane in the silicone oil or silicone grease adhering to the flange 47 evaporates, causing ultra-fine particles. Particles may be generated. Therefore, by applying the present invention to the fixing device 40 shown in FIGS. 8 and 9, it is possible to suppress the generation of ultrafine particles.

Next, the fixing device 50 shown in FIGS. 10 and 11 is a fixing device including a ceramic heater (heater 53), like the fixing device 40 shown in FIGS. 8 and 9 described above. Specifically, the fixing device 50 shown in FIGS. 10 and 11 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. 11), a heat sensitive element 58 as a temperature sensing member (see FIG. 11), and a cover. A member 59 (see FIG. 11) 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. 10 and 11 are the same as those of the fixing belt 51 shown in FIGS. 8 and 9. 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, the fixing device 60 shown in FIGS. 12 and 13 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. 12 and 13 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. 13), and a ring 68 as a sliding member (see FIG. 13). 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. 12 and 13 are 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. 14 and 15 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. 14 and 15 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. 15) 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. 14 and 15 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. 14 and 15 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. 16 and 17 is a fixing device that includes a ceramic heater (heater 83) as a heat source, like the fixing device 40 shown in FIGS. 8 and 9 described above. Specifically, the fixing device 80 shown in FIGS. 16 and 17 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. 17) 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. 16 and 17 are the fixing belt 41, pressure roller 42, and 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 silicone oil or silicone is used as a lubricant between the fixing belt 81 and the heat diffusion member 88 to improve sliding properties. Grease is applied. 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, when the temperature of the arcuate guide 87 rises due to the heat generated by the heater 83, the 12-17-mer siloxane in the silicone oil or silicone grease adhering to the arcuate guide 87 evaporates, resulting in ultrafine particles. Small particles may be generated. Therefore, by applying the present invention, it is possible to suppress the generation of ultrafine particles.

Next, the fixing device 90 shown in FIGS. 18 and 19 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 roller, a nip forming member 94, a support member 95, a guide member 98, a lubricant applying member 99 as a lubricant supply member, and a bearing 97 (see FIG. 19). .

As shown in FIG. 18, 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. Silicone oil or silicone grease is applied as a lubricant to reduce

Therefore, when the heating roller 96 is heated and the bearing 97 is affected by the heat, the temperature of the silicone oil or silicone grease adhering to the bearing 97 rises, causing the 12-17-mer siloxane to volatilize and become ultra-fine. Small particles may be generated. Therefore, it is preferable to apply the present invention to the fixing device shown in FIG. 18 as well. This makes it possible to reduce the number of ultrafine particles 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. 20 and 21.

The fixing device 110 shown in FIGS. 20 and 21 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. 21). ).

The fixing belt 111 shown in FIG. 20 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. 20 also includes a belt holding member 122 that holds both ends of the fixing belt 111 in the longitudinal direction. When the temperature of the silicone oil or silicone grease increases, the 12-17-mer siloxane may evaporate and ultrafine particles may be generated. Therefore, by applying the present invention to such a fixing device 110, it is possible to effectively suppress the generation of ultrafine particles, as in each of the above embodiments.

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

An inkjet image forming apparatus 2000 shown in FIG. 22 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. 23, 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. 23, 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. 23, 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 ultrafine particles will be generated from the silicone oil or silicone grease that adheres to the belt holding member 298. Therefore, by applying the present invention to such a drying device 206 as well, generation of ultrafine particles can be effectively suppressed.

Further, the present invention is also applicable to an image forming apparatus including a lamination processing apparatus as shown in FIG. 24.

The image forming apparatus 4000 shown in FIG. 24 includes a lamination 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. The thermal pressure roller 440 is pressurized by a heating source such as a heater, and both ends in the longitudinal direction are rotatably held by a pair of rotating body holding members such as bearings.

In the image forming apparatus 4000 shown in FIG. 24, 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 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, when 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, ultrafine particles are generated from the silicone oil or silicone grease that adheres to the bearing. There is a possibility. Therefore, by applying the present invention to the lamination processing apparatus 401 including such a hot pressure roller 440, it is possible to effectively suppress the generation of ultrafine particles.

Further, the present invention includes a heating device, a fixing device, and an image forming device 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 is equipped with silicone oil or silicone grease, and the concentration of 12-mer or more and 17-mer or less siloxane contained in the silicone oil or silicone grease is 1250 ppm or less.

[Second configuration]
In a second configuration, in the heating device of the first configuration, the rotating body holding member contains glass fiber.

[Third configuration]
A third configuration is a heating device of the first or second configuration in which the maximum temperature of the rotating body holding member during 10 minutes of continuous printing is 200° C. or higher and 240° C. or lower.

[Fourth configuration]
A fourth configuration is a heating device according to any one of the first to third configurations, in which the concentration of siloxane of 12-mer or more and 17-mer or less contained in the silicone oil or the silicone grease is 500 ppm or less. It is.

[Fifth configuration]
A fifth configuration is a fixing device that heats a recording medium carrying an unfixed image using the heating device of any one of the first to fourth configurations and fixes the unfixed image on the recording medium. be.

[Sixth configuration]
In a sixth configuration, in the fixing device of the fifth configuration, an endless belt as the rotating body, a facing member disposed facing the outer circumferential surface of the belt, and a facing member disposed opposite to the outer circumferential surface of the belt, and a The fixing device includes a nip forming member that contacts the member and forms a nip between the belt and the opposing member.

[Seventh configuration]
A seventh configuration is an image forming apparatus including the heating device of any one of the first to fourth configurations, or the fixing device of the fifth or sixth configuration.

20 Fixing device (heating device)
21 Fixing belt (rotating body, belt)
22 Pressure roller (opposing member)
23 Heater (heating source)
24 Nip forming member 27 Belt holding member (rotating body holding member)
100 Image forming apparatus N Nip section P Paper (recording medium)
X Longitudinal direction

Japanese Patent Application Publication No. 2013-164453

Claims (7)

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 silicone oil or silicone grease that adheres to the rotating body holding member,
A heating device characterized in that the silicone oil or the silicone grease has a concentration of 12-mer or more and 17-mer or less siloxane of 1250 ppm or less. The heating device according to claim 1, wherein the rotating body holding member contains glass fiber. The heating device according to claim 1 or 2, wherein the maximum temperature of the rotating body holding member during 10 minutes of continuous printing is 200°C or more and 240°C or less. The heating device according to claim 1 or 2, wherein the concentration of 12-mer or more and 17-mer or less siloxane contained in the silicone oil or the silicone grease is 500 ppm or less. A fixing device, characterized in that the heating device according to claim 1 or 2 is used to heat a recording medium carrying an unfixed image to fix the unfixed image on the recording medium. an endless belt as the rotating body;
a facing member disposed facing the outer circumferential surface of the belt;
The fixing device according to claim 5, further comprising a nip forming member that contacts the opposing member via the belt and forms a nip portion between the belt and the opposing member. An image forming apparatus comprising the heating device according to claim 1 or 2.

Images