JP2006171189A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of decomposing odorous gas produced at a fixing nip. <P>SOLUTION: The image forming apparatus has a fixing member for heating and fixing an unfixed toner image on a transfer material, a fixing device frame holding ambient air around the fixing member in a fixing device, and a photocatalyst with organic gas decomposing property at least in a part of the fixing device frame and inside thereof. Or the image forming apparatus has the fixing member for heating and fixing the unfixed toner image on the transfer material and has the photocatalyst having the organic gas decomposing property on a partition wall provided between a transfer material heating place of the fixing member and a paper discharge part, or the image forming apparatus uses a heater which emits visible light to a heat source of the fixing member to heat and fix toner and is provided with a member, which has the photocatalyst decomposing organic gas with the visible light, in the optical path of the visible light emitted by the heater. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic system.

  Conventionally, an image fixing device used in an electrophotographic apparatus forms an electrostatic image on a photoconductor by an exposure device that performs exposure according to an image signal on the photoconductor uniformly charged by a charging device. The electrostatic image is formed on the transfer material by the developing device, the toner image is transferred onto the transfer material by the transfer device, the unfixed image on the transfer material is fixed on the transfer material by the fixing device, and the fixed image is transferred from the paper discharge unit. An image is formed by discharging the transfer material formed on the outside of the apparatus.

  In a fixing device, in order to fix a toner mainly composed of a thermoplastic resin to a recording material such as paper, a heat fixing method mainly including heating and pressurization, particularly a heat roller fixing method is generally employed. It is. This heat roller fixing method uses a so-called fixing roller and a pressurizing layer in which a layer having a high releasability such as PFA, PTFE, or other fluororesin or silicon rubber is formed on a metal element tube such as aluminum or iron. It consists of rollers, and a halogen lamp or the like is built in each roller as a heating source as required. Then, the fixing roller heated to a predetermined temperature is pressed against the pressure roller to form a nip portion, and the transfer material on which the unfixed toner image is placed is held in the nip, whereby the toner image Is fixed to the transfer material by heating and pressing. The transfer material on which the toner image is fixed by the fixing device is conveyed to a paper discharge unit by a driving force of a roller pair, a belt, or the like, and is discharged from the paper discharge unit to the outside of the image forming apparatus.

  In general, the fixing device is often held at a high temperature of about 150 to 230 ° C. In order to prevent the toner in the developing device and the cleaner device from being thermally deteriorated by the heat of the fixing device, the heat of the fixing device and the fixing device It has the frame for intercepting the air heated by.

  This frame plays an important role from the viewpoint of reducing the power consumption of the fixing device because it reduces the heat radiation of the fixing device.

  However, since organic substances such as toner and paper are heated in the fixing step, an extremely small amount of organic substances corresponding to these materials may be vaporized by heating, which may be accompanied by odor.

  As a toner applied to these image forming apparatuses, conventionally, fine powder in which a dye / pigment is dispersed in a natural or synthetic resin has been used. For example, particles in which a colorant is dispersed in a binder resin such as polystyrene are finely pulverized to about 1 to 30 μm are used as toner. As the magnetic toner, a toner containing magnetic particles such as magnetite is used. On the other hand, in the case of a method using a so-called two-component developer, carrier particles such as glass beads and iron powder are usually mixed with toner.

  Today, such a recording method has been widely used not only for general copying machines but also for computer output and microfilm printing. Therefore, the required performance has become higher, and various performances such as smaller size, lighter weight, lower energy, more maintenance-free and more personal have been required at the same time. In order to satisfy these requirements, demands on toner have become stricter in various aspects.

  For example, as described above, the range of application is widened and it is used in general offices and homes. As a toner, not only the safety as a substance but also the odor generated at the time of fixing can be taken care of. It has become necessary.

  Of course, this odor problem is an important issue when considering the user and manufacturer's position as described above, but generally it contains synthetic resin as the main component and uses its softening / melting due to heating. Considering the method of fixing a toner image fixed on a transfer material such as paper, it is technically not easy. Also, in order to solve this problem, there is no point in reducing development characteristics such as image quality and toner durability.

  In order to satisfy these performances simultaneously, various methods have been considered. However, the method of adding additives often complicates the system and often causes unexpected problems.

  Therefore, it is desirable to improve the binder resin itself as the toner. For this purpose, it is considered good to reduce the residual amount of solvents and polymerizable monomers that cause odor in the binder resin, and various methods have been developed so far, including the effect on other development characteristics. Has been proposed.

  For example, Patent Document 1 discloses that an offset is generated by using a polymer having a content of a solvent or a polymerizable monomer of less than 0.1% by weight as a binder resin for toner. It has been proposed to improve storage stability, fluidity and the like.

  Further, Patent Document 2 has a description that the residual of the polymerizable monomer affects the triboelectric chargeability, blocking resistance, and fixability of the toner, and was used to obtain a polymer as a binder resin for toner. It has been proposed to reduce the residual solvent or polymerizable monomer.

  Further, Patent Document 2 discloses a toner for a toner having a residual monomer amount of 200 ppm or less, particularly for problems such as an on-site environment that deteriorates due to an odor generated during melt-kneading, or an odor generated during copying and an unpleasant feeling. Resin proposals have been made. There is a description that when the amount of the residual monomer exceeds 200 ppm, the blocking resistance and the vinyl chloride plasticizer resistance are lowered, and the problem of odor remains.

JP-A-55-155632 JP-A-53-017737 JP-A 64-070765

  However, especially when the problem of odor is targeted, it is not sufficient to simply reduce the amount of the remaining polymerizable monomer in consideration of the future application range such as electrophotography and electrostatic recording. .

  Conventionally, as a countermeasure, an air passage for sucking in air in the fixing atmosphere has been provided in the main body of the image forming apparatus, and a highly adsorbent filter such as an ozone filter is disposed in the exhaust section to the outside of the apparatus, and the odor component is converted into an ozone filter. Adsorption filter systems that reduce odor components to a predetermined amount or less by adsorption are often used. In general, the ozone filter also adsorbs / decomposes ozone generated in a charging process or the like collected through another air passage.

  However, since the adsorption filter system is a system that captures odor components on the filter surface, it can only capture volatile components according to the surface area of the adsorption filter. If the adsorbed substance completely covers the filter surface, the effect cannot be exerted any further, and the effect cannot be exhibited permanently. Therefore, in an image forming apparatus having a long main body life, periodic replacement is necessary. Frequent filter replacement increases the running cost of the image forming apparatus, which is undesirable and lacks simplicity. Also, from the viewpoint of consideration for the global environment, it is not preferable to frequently replace the filter which is a consumable part.

  In addition to the adsorption method that limits the amount of odor component adsorbed (processed amount), there are a combustion method that burns odor components, a catalyst method that decomposes using a catalyst, and a photocatalyst method that decomposes using a photocatalyst. Such combustion method, catalyst method, and photocatalyst method can decompose the odor component itself, so that it can be used semi-permanently unlike the adsorption filter method in which the efficiency is reduced by adsorption.

  If the odor component can be decomposed to a predetermined concentration or less, it can be combined with a charging method such as a charging roller method that generates a very small amount of ozone to eliminate the filter of the air inside the machine that needs to be replaced.

  Even when the effect of decomposition of odor components cannot be obtained so much, the life of the adsorption filter can be extended by reducing the amount of odor components introduced to the adsorption filter by decomposition.

  Here, each method will be described.

In the combustion method, heating is generally performed at a high temperature of about 750 ° C. or more, and the organic component is burned to decompose the organic component into CO ₂ and H ₂ O, thereby obtaining an effect. In order to maintain a high temperature of 750 ° C. or higher, a large amount of energy is required, and a strong heat insulation and cooling mechanism is required. Therefore, the machine becomes large and it is not realistic to be mounted on an electrophotographic image forming apparatus. . Even the improved catalytic combustion method requires a high temperature of about 350 ° C., and it is not realistic to mount it in the image forming apparatus.

As the catalyst system, the gas sucked from the fixing device is changed to MnO2 as disclosed in JP-A-11-161122.
A method of decomposing with a system catalyst filter has been proposed. However, this family of catalysts is generally effective in treating gases at 40-50 ° C. Therefore, it is not suitable for directly decomposing the hot odor gas in the fixing device, and an air passage for sucking the air in the fixing atmosphere and guiding it outside the fixing device is provided, and the catalyst is provided in the air passage away from the fixing device. A filter must be installed. Therefore, this type of catalyst filter cannot decompose odor components in the fixing device and in the very vicinity. Since the place where the odor component is generated is the fixing device, it is most effective that the vicinity of the fixing device has the highest odor component concentration and decomposes the odor component here.

  In addition, it is practically difficult to completely suck out the odor component in the vicinity of the fixing device through the air passage, and a part of the odor gas in the vicinity of the fixing device is discharged from the transfer material. Can flow out of mouth. This tendency is remarkable in an image forming apparatus having a short path length from the fixing unit to the paper discharge unit.

  Increasing the suction force (ie, the air volume) that sucks air in the vicinity of the fixing device reduces the outflow amount from the paper discharge port, but also removes heat from the fixing device together with the odor gas, so that the fixing device is cooled as a result. The power consumption required for the fixing device increases. There is no problem if the power during image formation is infinite, but the power that can be supplied to the image forming apparatus is limited and is not realistic. Also from the viewpoint of energy saving, reduction of the power consumption of the fixing device is a social request and is not preferable.

In this respect as well, it is desired to reduce the concentration of the odor component by processing the odor component in the fixing device or in the section from the fixing device to the paper discharge port. As a catalyst, titanium oxide-based catalysts have attracted attention. This is one that decomposes into carbon dioxide, water, and other low-molecular oxides by the oxidizing action of active oxygen generated in the energy band gap generated by irradiating the photocatalyst with visible light or ultraviolet light.

  Many have strong characteristics at high temperatures such as 800 ° C. Many titanium oxide-based photocatalysts have high efficiency in decomposing organic substances under ultraviolet light, but in recent years, as a technology to improve the decomposition efficiency in the visible light region, visible light in which an additive such as nitrogen is combined with titanium oxide. Responsive titanium oxide photocatalysts have been developed. As an example of mounting the photocatalyst system on a fixing device, the following technologies have been proposed. In Japanese Patent Laid-Open Nos. 09-244444 and 2000-347526, the surface layer of a fixing roller, a pressure roller, and a fixing inlet guide The photocatalyst layer is used for.

  In JP-A-2001-100585 and JP-A-2003-156862, a photocatalyst is used for the peeling claw and the non-contact separation member, respectively.

  Japanese Patent Laid-Open No. 2001-005326 uses a photocatalyst as a cleaning member that contacts the heating member and cleans the heating member.

  In each of these methods, a fixing roller, a pressure roller, a fixing inlet guide, a peeling claw, a non-contact separation member, a contaminated toner adhering to a roller contact surface of a cleaning member in contact with a heating member is decomposed by a photocatalytic effect. This technique is not intended for decomposing odor components in and near the fixing machine, and therefore, a photocatalyst is disposed at a position in contact with the transfer material and the contaminated toner. For this purpose, it is considered an optimal arrangement.

  However, in the object of the present invention of decomposing odor components released into the ambient air in the vicinity of the fixing device, initially, although a certain effect can be obtained in decomposing the odor components, as the durability progresses, the odor components are generally passed. The area where the photocatalyst and the odor component are in contact with each other is reduced during the period until the contaminants are decomposed when the paper or the fixing member rotates or until the pollutant is decomposed when contaminated with paper dust or toner. Therefore, the effect tends to decrease.

  Furthermore, in the system used for the peeling nail and the non-contact separating member, the area of the photocatalyst was too small, so the decomposition effect of the odor component was too small.

  Furthermore, since many parts of the photocatalyst are in contact with the transfer material while the paper is passing, the contact with the atmospheric air is cut off, and during continuous image formation, the contact of the odor component released into the atmospheric air near the fixing device. Area to be reduced, and the decomposition efficiency of odor components is reduced.

  As described above, in the configuration in which the conventional photocatalyst is used for the fixing device, although it is effective for decomposing the adhered contaminants, the performance deterioration due to durability is large, or the air in the fixing unit and the vicinity thereof is Since the contact area was too small, there was no stable and sufficient odor component in the fixing device that was effective throughout the durability.

  Further, as an example of using a photocatalyst in the vicinity of the fixing device, for example, in the invention described in Japanese Patent Application Laid-Open No. 2002-169432, an air cleaner using a photocatalytic filter is incorporated. Since this is also a method of once sucking the air in the vicinity of the fixing device and then processing it, the odor component cannot be decomposed in and in the vicinity of the fixing device in the same manner as described in the catalyst system, which is not efficient.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of decomposing odorous gas generated at a fixing nip portion.

  In order to achieve the above object, a first aspect of the present invention is directed to a fixing device frame having a fixing member for heating and fixing an unfixed toner image on a transfer material, and holding air around the fixing member in the fixing device. And a fixing device frame and a photocatalyst having organic gas decomposability in at least a part of the fixing device frame.

  The invention according to claim 2 has a fixing member for heat-fixing an unfixed toner image on the transfer material, and decomposes organic gas into a partition provided between the transfer material heating portion of the fixing member and the paper discharge unit. It has the photocatalyst which has property.

  According to a third aspect of the present invention, a heater that emits visible light is used as a heating source of a fixing member for heat-fixing toner, and the organic gas is decomposed by visible light in the optical path of visible light emitted from the heater. A member having a photocatalyst is provided.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the photocatalyst is disposed at a position where the transfer material and the offset toner offset from the transfer material do not contact.

  The invention according to claim 5 is the invention according to any one of claims 1 to 3, characterized in that the photocatalyst is provided in the vicinity of an exhaust port for exhausting the atmosphere in the fixing device.

  The invention according to claim 6 has the light source or optical path for irradiating the photocatalyst with visible light or ultraviolet light on the downstream side in the paper conveyance direction of the fixing nip portion in the invention according to any one of claims 1 to 3. It is characterized by that.

  According to the seventh aspect of the present invention, a heater that emits visible light is used as a heating source of a fixing member for heat-fixing toner, and at least a part of the visible light irradiated surface of the fixing member has an organic gas decomposability. A photocatalyst layer is formed.

  The invention according to claim 8 is the invention according to any one of claims 1 to 6, wherein a photocatalytic filter is used as a photocatalyst.

  According to the first aspect of the present invention, the image forming apparatus includes a fixing member for heat-fixing an unfixed toner image on the transfer material, and has a fixing device frame that holds air around the fixing member in the fixing device. By having a photocatalyst having organic gas decomposability in at least a part of the fixing device frame and the inside thereof, it becomes possible to decompose odorous gas generated in the fixing nip portion.

  According to the second aspect of the present invention, the partition wall has a fixing member for heating and fixing the unfixed toner image on the transfer material, and is provided between the transfer material heating portion of the fixing member and the paper discharge unit. By having a photocatalyst having organic gas decomposability in the odor gas, it is possible to decompose odorous gas generated in the fixing nip portion.

  According to a third aspect of the present invention, a heater that emits visible light is used as a heating source of a fixing member for heat-fixing toner, and an organic gas is decomposed by visible light in an optical path of visible light emitted from the heater. By providing a member having a photocatalyst capable of decomposing, the odorous gas generated in the fixing nip portion can be decomposed without requiring a dedicated light source.

  According to the fourth aspect of the present invention, the photocatalyst is disposed at a position where the transfer material and the offset toner offset from the transfer material are not in contact with each other, whereby the decomposition of the odorous gas generated in the fixing nip portion is changed in durability and image formation. It became possible to be stable without being influenced by the light on the photocatalyst by the transfer material at the time and the shielding of the atmosphere air.

  According to the invention described in claim 5, by providing the photocatalyst in the vicinity of the exhaust port for exhausting the atmosphere in the fixing device, it becomes possible to more efficiently decompose the odorous gas generated in the fixing nip portion. It was.

  According to the invention described in claim 6, the light source or the optical path for irradiating the photocatalyst with visible light or ultraviolet light is provided on the downstream side in the paper conveyance direction of the fixing nip portion, so that the odorous gas generated in the fixing nip portion. Can be decomposed more efficiently.

  According to the seventh aspect of the present invention, a heater that emits visible light is used as a heating source of the fixing member for heat-fixing the toner, and organic gas decomposition is performed on at least a part of the visible light irradiated surface of the fixing member. By forming the photocatalyst layer having the property, it became possible to decompose the odorous gas generated in the fixing nip portion.

[Example 1]
FIG. 2 is a schematic cross-sectional view for explaining the outline of the image forming apparatus according to the first embodiment.

  The surface of the image carrier 1 uniformly charged by the charging device 3 is irradiated with a laser or the like according to image information to form an electrostatic latent image. The electrostatic latent image is developed with toner containing styrene acrylic resin as a main component by the developing device 3 to form a toner image on the image carrier 1, and then the toner image on the image carrier 1 is transferred to the transfer material by the transfer device 7. Transfer on top. The unfixed toner image on the transfer material in this state is heated and pressed by the fixing device 9 to obtain an electrophotographic image.

  Next, an outline of the fixing device 9 according to the first embodiment will be described with reference to FIGS. 1 and 3.

  The fixing device 9 includes a fixing roller 10 including a halogen heater 12 therein, a pressure roller 11, a fixing roller 10, an upper fixing claw 16 and the like. The fixing roller 10 has a fluororesin formed on a surface layer. . The pressure roller 11 has a silicon rubber layer of about 5 mm on a SUS core, and the top layer is also covered with a fluorine resin such as a PFA tube. Both the fixing roller 10 and the pressure roller 11 have an outer diameter of 50 mm.

  A thermistor 13 for detecting the temperature of the fixing roller 10 is in contact with the sheet passing area of the transfer material on the surface of the fixing roller 10, and the output of the fixing heater 12 is controlled by the detected temperature. A halogen heater having a maximum output of 850 W during image formation by the fixing heater 12 was used. This is because the power of the entire image forming apparatus is set to the maximum power within the range of 1500 W or less, which is a standard value of a general power outlet, and 60 sheets of A4 size transfer material are passed per minute. it can. The fixing roller 10 is controlled to be kept at 200 ° C. by a control device. The fixing roller and the pressure roller are each supported by a support member (not shown) via a heat insulating bush and a bearing arranged at the end in the longitudinal direction.

  In the first embodiment, in order to prevent the air in the fixing unit from diffusing outside the fixing device, a photocatalyst layer is provided on the inner surface layer of the fixing frame 20 surrounding the fixing roller 10 and the pressure roller 11, and a halogen is formed there. It is characterized by being irradiated with visible light emitted from a heater. The purpose is to activate the photocatalyst in the shaded area.

  Here, the fixing frame body is a general term for a partition member for preventing diffusion of air and heat around a fixing member such as a fixing roller and a pressure roller and a nip portion into the image forming apparatus.

  The fixing frame has an opening for transferring the transfer material at the transfer material inlet side on the upstream side of the nip part and the transfer material outlet part on the downstream side of the nip part. It is devised so that odor components emitted from the part are not diffused outside the fixing device as much as possible.

  The photocatalyst layer on the inner surface of the fixing frame 20 was a visible light responsive titanium oxide photocatalyst in which a small amount of an additive such as nitrogen was bound to titanium oxide. This photocatalyst can obtain the effect of the photocatalytic reaction with visible light and ultraviolet light of 550 nm or less.

  The emission wavelength of the halogen heater has a broad emission characteristic with an emission peak in the vicinity of 700 nm to 15000 nm, and mainly emits infrared light from visible light. In many cases, more than 80% of the total is infrared light, but by setting the color temperature higher, the peak can be set on the short wavelength side, and the emission ratio in the visible light range is set relatively high. it can.

  The wavelength of the emission peak of the halogen heater can be obtained by the equation 2897 ÷ color temperature (K).

  In Example 1, a heater having a color temperature of about 3200K was used. As a result, the emission peak is about 90 nm, and the relative intensity at 550 nm at which the photocatalytic effect for the peak portion starts to be obtained is about 40 to 50%. For reference, the relative intensity at 400 nm with respect to the peak portion is about 15 to 20%. The light emitting area in the longitudinal direction perpendicular to the fixing roller rotation direction was set to the same length as the so-called surface length in which a fluororesin layer was formed on the fixing roller. Here, the light emitting region in the longitudinal direction refers to a region where the filament is intermittently densely wound.

  The halogen heater is held by a small heater support member outside the fixing roller in the longitudinal direction, and a photocatalytic layer is also formed on the inner surface layer.

  Using such an image forming apparatus, a sensory test was performed on the odor released outside the apparatus when the image was formed.

  As a comparative example, an example in which a photocatalyst is not used is Comparative Example 1, an example in which a photocatalyst is used for a fixing roller, a pressure roller, a fixing inlet guide, and a peeling claw, Comparative Example 2, and Example 1 from a halogen heater to a frame body An example in which the light beam is completely blocked is listed as Comparative Example 3.

  The sensory test was conducted by subjective evaluation, with 10 being the best point where 1 does not feel odor at all, 10 being the worst point, and the acceptable odor level being 5 points. Each configuration is evaluated at the point where the odor is felt most strongly around the image forming apparatus. In addition, 20 subjects were used for this evaluation, and the average score was made into the score of each structure.

  In any configuration comparison, 20 subjects were not replaced. In this test, an adsorption filter such as an ozone filter is not provided in the exhaust path from the fixing device in any configuration.

  The results are shown in the table below. This result is considered to include an error of around 0.5 points in reproducibility.

このように実施例１では臭気のレベルが大幅に改善している点が確認された。比較例３との比較にいても、実施例１の効果が光触媒効果によりもたらされている点が確認できた。

As described above, in Example 1, it was confirmed that the odor level was greatly improved. Even in comparison with Comparative Example 3, it was confirmed that the effect of Example 1 was brought about by the photocatalytic effect.

  In Comparative Example 2, as shown in JP 09-244444, JP 2000-347526, JP 2001-100585, JP 2003-156926, JP 2001-005326, a fixing roller and a pressure roller A similar test was conducted in a system in which a photocatalyst layer was provided on the roller contact surface of a cleaning member that contacts a fixing inlet guide, a peeling claw, a non-contact separation member, and a heating member, but almost no odor component decomposition effect was obtained. I couldn't. Because the light flux of the halogen lamp does not directly hit the roller contact surface of the cleaning roller that contacts the fixing roller, pressure roller, fixing inlet guide, peeling claw, non-contact separation member, and heating member, the photocatalytic activity did not increase. I think that the.

  As described above, in JP 09-244444, JP 2000-347526, JP 2001-100585, JP 2003-156926, JP 2001-005326, and JP 2002-169432, in terms of configuration, In order to activate the photocatalytic reaction, it is necessary to provide a light source of ultraviolet light or visible light separately, or provide an optical path for introducing light outside the apparatus into the fixing device. For this reason, the configuration is complicated, the size of the image forming apparatus is increased, and the cost increases due to the provision of a light source. Furthermore, providing another light source is not preferable because it consumes several tens of watts of power. The power consumption of the first embodiment is that a photocatalytic reaction is activated using a visible light reactive photocatalyst in a visible light irradiation range emitted from a heating source such as a fixing roller, so that a new light source or the like is not arranged. It is greatly superior in that the effect is obtained, and can be said to be a very realistic configuration.

  Unlike Japanese Patent Application Laid-Open No. 2002-169432 and Japanese Patent Application Laid-Open No. 11-161122 using a catalyst system, the odor component in the fixing device can be decomposed directly in the fixing device where the odor component is generated. Components can be reduced efficiently. As a result, it was possible to effectively prevent leakage of odor components from the paper discharge port without performing strong air intake by the fan.

  Further, since it is not necessary to suck the fixing atmosphere air by the fan, the effect can be obtained without hindering the heat retaining property of the fixing device. As a result, the conventional example 1 has an advantage of operating power of about 30 to 50 W in combination with the heat radiation of the fixing device and the driving power of the fan.

  A comparison with a system in which an adsorption filter such as an ozone filter is provided in the exhaust path from the fixing device as in the conventional example is shown below. Comparison between the initial stage and results after endurance of 300,000 sheets are shown.

前述のように、吸着フィルタを用いた系においては、自身の表面に臭気成分を吸収する原理であるため、初期の特性は非常に高いものの、耐久後には全体の表面積に占める吸着済みの面積が多くなり、吸着効率が低下している点が分かる。この吸着性のフィルタは３０万枚以下で交換を繰り返すことが望ましく、半永久的な効果を得ることが困難であることが分かる。

As described above, in the system using the adsorption filter, since it is a principle that absorbs odor components on its surface, the initial characteristics are very high, but after the endurance, the adsorbed area occupies the entire surface area. It can be seen that the adsorption efficiency has decreased and the adsorption efficiency has decreased. It can be seen that it is desirable to repeat replacement of this adsorptive filter with 300,000 sheets or less, and it is difficult to obtain a semi-permanent effect.

On the other hand, Example 1 is based on the principle of decomposing odor components by its photocatalytic reaction on its own surface, and therefore the surface area that causes catalytic activity does not decrease. It was. As described above, it was confirmed that Example 1 has significantly less durability deterioration, superiority in running cost, and less damage to the global environment.
[Examples 2 and 3]
Further, as shown in FIG. 5, a reflection plate that reflects visible light emitted from a halogen lamp is provided in the vicinity of the end of the fixing roller, and the photocatalyst provided at a place other than the end of the roller is irradiated with visible light. The effect is obtained in the same manner as in Conventional Example 1. At this time, an example in which the photocatalyst surface on the downstream side of the nip portion of the fixing frame body is irradiated as shown in FIG. 5 is referred to as Example 2, and an approximately provided on the upstream side of the nip portion of the fixing frame body as shown in FIG. An example in which the photocatalyst surface having the same area is irradiated is referred to as Example 3. The purpose is to activate the photocatalysts in each shaded area. The sensory test similar to Example 1 was performed with both configurations.

実施例２，３共所定の効果が得られた。特に、ニップ部より下流側に光触媒を設けた実施例２は、実施例１以上の効果が得られた。しかし、実施例３では、実施例１以下の効果しか得られなかった。

In Examples 2 and 3, a predetermined effect was obtained. In particular, Example 2 in which the photocatalyst was provided on the downstream side of the nip portion was more effective than Example 1. However, in Example 3, only the effect below Example 1 was acquired.

  This result is considered as follows.

  The transfer material of the fixing device enters from the upstream side of the nip portion, is heated in the nip and rises in temperature, and is discharged from the downstream portion of the nip. For this reason, the generated amount of odorous gas is mainly discharged downstream of the nip. Therefore, the concentration of the odor component is overwhelmingly higher on the downstream side of the nip portion in the transfer material conveyance direction. That is, in order to activate the photocatalytic reaction downstream from the nip portion, it is considered effective to irradiate light here and to activate the photocatalytic reaction positively.

  Accordingly, providing a photocatalyst downstream from the nip portion of the fixing device or adopting a configuration capable of irradiating more visible light is an important point for maximizing the decomposition efficiency of odor components.

In Example 1, visible light from a halogen heater was irradiated to the end portion of the fixing roller to activate the photocatalyst at this part. From the results of Examples 2 and 3, the downstream side portion of the nip part was odorous. It can be interpreted that it was strongly involved in the decomposition of the components. In the first embodiment, a heater holding member as shown in FIG. 4 may be used to positively irradiate the downstream side of the nip with visible light while ensuring the heater holding property on the upstream side of the nip. .
[Example 4]
An example in which a filter-like photocatalyst is installed at an outlet of an air flow discharged from a fixing device, and the visible light of a halogen lamp is guided to the photocatalyst filter using a reflector, as Example 4 with reference to FIGS. explain.

  In Example 4, a photocatalytic filter is provided on the fixing roller surface side of the transfer material conveyance path at the transfer material outlet portion of the fixing frame downstream of the fixing nip portion. In this embodiment, in order to prevent temperature rise in the apparatus, high-temperature air in the vicinity of the fixing device is exhausted using an air passage, and this intake port is provided in the vicinity of the surface opposite to the fixing roller of the photocatalytic filter.

  In this example, an object is to more efficiently decompose the odor component by disposing the photocatalyst on the downstream side of the air flow from the inner surface of the fixing device and actively collecting the odor component in the filter. Part of the visible light passes through the filter and reaches the inside of the filter. The filter generally has a large surface area, and the photocatalytic activity can be increased over a wide area. By using the filter, the odor component at a high concentration position downstream of the inner nip of the fixing frame body can be decomposed in a larger area.

  In Example 4, the same sensory test as in Example 1 was performed, and the level was as high as 2.1. This seems to be because contact between the odor component and the photocatalyst became more aggressive.

  In Example 4, the visible light of the halogen lamp was guided to the photocatalytic filter using a reflector, but this light source is effective even with a separate light source of visible light or ultraviolet light provided separately as shown in FIG. It is done. However, in this case, it is greatly inferior to the first and second embodiments in that the device size, cost, and power consumed by the light source are increased.

  In this case, although the effect of odor decomposition can be obtained even if a light source is arranged inside the fixing frame, the fixing frame is generally at a high temperature of 100 ° C. or more, so from the viewpoint of thermal deterioration of the light source. It is preferable to provide the outer side of the fixing frame.

  As described above, in an image forming apparatus that exhausts air in the vicinity of the fixing device using an air passage, the photocatalyst is arranged on the air flow, so that the odor gas can be more efficiently guided to the photocatalyst. Can be raised.

  As a derivative example of Embodiment 4, as shown in FIG. 9, a photocatalytic filter is installed in the visible light irradiation region of the halogen heater in the vicinity of the longitudinal end of the fixing roller, and air is sucked from here, so that neither a light source nor a reflector is used. The effect can be obtained. Since the effect can be obtained with the simplest configuration, it can be said that the configuration is very effective in reducing the size of the fixing device.

  Further, in an image forming apparatus that exhausts air in the vicinity of the fixing device using an air path, a configuration in which the air in the vicinity of the fixing passes through an ozone filter or the like may be set. In this case, the odor component that has not been completely decomposed by the photocatalyst is adsorbed by the ozone filter, so that the odor component can be more reliably prevented from being released from the apparatus. In this configuration, since most of the odor components have already been decomposed by the photocatalyst, the life of the ozone filter can be extended compared to the case where only the ozone filter is used without using the photocatalyst. This is because the decrease in the adsorption area of the ozone filter due to the adhesion of the odor component can be reduced by reducing the odor component reaching the ozone filter.

  Further, by providing a partition wall for the odor component emitted from the fixing device between the fixing device nip portion and the paper discharge port, and providing a photocatalytic filter here, discharge of the odor component from the paper discharge port can be reduced.

  However, part of the odor leaks from the opening on the upstream side of the fixing nip due to the air flow accompanying the rotation of the fixing roller. In consideration of this, it is most efficient to provide a photocatalytic filter on the fixing frame that is a partition wall near the downstream position of the nip portion. Since the odor component leaking from the fixing device can be decomposed most reliably because it can be decomposed at the location closest to the generation location, and the odor component can be decomposed at a high concentration position, Example 4 is the optimum position. It can be said that.

  In the fourth embodiment, the photocatalytic filter is provided on the fixing roller side with respect to the transfer material conveyance path. However, the photocatalytic filter may be provided on the pressure roller side with respect to the transfer material conveyance path. However, since the transfer material shields the contact with the air containing the odorous component generated on the fixing roller side while passing through the transfer material, it is provided on the toner fixing surface side, that is, the fixing roller side as in the fourth embodiment. Is preferred.

  Even if the filter is not a photocatalytic filter, a member having a photocatalytic surface is provided at the outlet of the air from the fixing device, and even if this is irradiated with visible light, the efficiency is slightly inferior to that of the fourth embodiment. It is done.

  However, it is necessary to provide the photocatalyst layer other than the contact surface (conveyance surface) of the member that can come into contact with the transfer material. When the transfer material is provided on the transfer material conveyance surface, the transfer material blocks the optical path, making it difficult to supply a stable amount of light to the photocatalyst surface, and the odor released from the nip in contact with the photocatalyst surface. The point where contact between the air containing the component and the photocatalyst is hindered, the photocatalyst layer is worn by the transfer material, and the contact with visible light and odorous components in the air is difficult to be secured through durability due to adhesion of paper dust etc. However, a stable effect on the decomposition of odor components during image formation could not be obtained.

  Even when it is provided on the fixing roller, pressure roller, and cleaning member, it is similarly affected by wear due to durability, and the decomposition of substances such as paper dust toner on the surface does not necessarily catch up with the decomposition speed by the photocatalyst, and air A stable effect was not obtained throughout the endurance against the decomposition of the odor components in it.

The fourth embodiment is different from Japanese Patent Application Laid-Open No. 2002-169432 in which an air purifier is disposed around the fixing device and Japanese Patent Application Laid-Open No. 11-161122 in which a catalyst system is used. Since the odor component can be decomposed directly in the fixing device where the odor component is generated, the odor component can be efficiently reduced. As a result, it was possible to effectively prevent leakage of odor components from the paper discharge port without performing strong air intake by the fan.
[Example 5]
An example in which a visible light photocatalyst layer is formed on the inner surface of the fixing roller in the shaded area in FIG. 11 will be described in Example 5.

  An Okitsumo layer is formed on the fixing roller core, and a visible light photocatalyst layer is formed thereon. The inner surface of the fixing roller is the place where the visible light of the halogen heater is exposed most, and the decomposition efficiency for the same amount of odorous substances is very high. However, the concentration of odorous substances in the roller is low. However, also in this example, a result superior to Comparative Examples 1 to 3 of Example 1 could be obtained.

  Although this mechanism is not clear, it is considered that a part of the odor component in and near the fixing device can be decomposed by the active oxygen generated in the fixing roller by the photocatalyst.

  In the fifth embodiment, the visible light photocatalyst layer is formed on the entire inner surface of the roller. However, in the longitudinal direction of the fixing roller, the region corresponding to the sheet passing region of the transfer material is provided with high absorption of infrared light. A photocatalyst layer may be provided in part, such as a photocatalyst layer, at both ends corresponding to the outside of the paper passing area.

  Further, an air passage that guides at least a part of the air on the downstream side of the nip portion into the roller may be provided. In this case, the photodecomposition of the odor component can be promoted more effectively.

FIG. 2 is a schematic top cross-sectional view illustrating an overview of the fixing device according to the first embodiment of the present invention. 1 is a schematic front sectional view for explaining an outline of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic front cross-sectional view illustrating an overview of a fixing device according to Embodiment 1 of the present invention. FIG. 3 is a schematic front cross-sectional view illustrating a heater support body shape of a derivative example of the fixing device according to the first embodiment of the present invention. FIG. 6 is a schematic top cross-sectional view illustrating an outline of a fixing device according to Embodiment 2 of the present invention. FIG. 6 is a schematic top cross-sectional view illustrating an outline of a fixing device according to a third embodiment of the present invention. FIG. 6 is a schematic front sectional view for explaining an outline of a fixing device according to a fourth embodiment of the present invention. FIG. 6 is a schematic top cross-sectional view illustrating an outline of a fixing device according to a fourth embodiment of the present invention. FIG. 9 is a schematic top cross-sectional view illustrating an outline of a fixing device according to a derivative example of Embodiment 3 of the present invention. FIG. 10 is a schematic front cross-sectional view illustrating an outline of a fixing device different from FIG. 9 of Embodiment 3 of the present invention. FIG. 6 is a schematic top cross-sectional view illustrating an outline of a fixing device according to a fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image carrier 2 Pre-exposure device 3 Charging device 4 Developing device 7 Transfer device 8 Cleaning device 9 Fixing device 10 Heating roller 11 Pressure roller 12 Fixing heater 13 Temperature detecting device 14 Control device 15 Fixing inlet guide 16 Fixing upper separation claw 17 Separation Claw Under Fixing 18 Cleaning Web 19 Web Pressing Roller 20 Fixing Frame Body 21 Paper Discharge Portion 22 Heater Support Body 23 Air Path 24 External Light Source 25 Photocatalytic Filter 26 Reflector

Claims (8)

  A fixing member for heat-fixing an unfixed toner image on a transfer material, a fixing device frame for holding air around the fixing member in the fixing device, and at least one of the fixing device frame and the inside thereof. An image forming apparatus comprising a photocatalyst having organic gas decomposability in a part.   It has a fixing member for heat-fixing an unfixed toner image on the transfer material, and has a photocatalyst having organic gas decomposability in a partition wall provided between the transfer material heating portion of the fixing member and the paper discharge unit. An image forming apparatus.   A heater that emits visible light is used as a heating source of a fixing member for heat-fixing toner, and a member having a photocatalyst that decomposes organic gas with visible light is provided in the optical path of visible light emitted from the heater. An image forming apparatus.   4. The image forming apparatus according to claim 1, wherein the photocatalyst is disposed at a position where the transfer material and the offset toner offset from the transfer material are not in contact with each other.   The image forming apparatus according to claim 1, wherein the photocatalyst is provided in the vicinity of an exhaust port that exhausts the atmosphere in the fixing device.   The image forming apparatus according to claim 1, further comprising a light source or an optical path for irradiating the photocatalyst with visible light or ultraviolet light on a downstream side of the fixing nip portion in a paper conveyance direction.   A heater that emits visible light is used as a heating source of the fixing member for heat-fixing the toner, and a photocatalyst layer having organic gas decomposability is formed on at least a part of the visible light irradiated surface of the fixing member. An image forming apparatus.   The image forming apparatus according to claim 1, wherein a photocatalytic filter is used as the photocatalyst.

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