JP2006330480A - Fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently collect, decompose/remove volatile organic compound generated near a nip part by suppressing suction of heat from a fixing object at the nip part. <P>SOLUTION: The fixing device 7 constituted so that an unfixed toner image is fixed to a recording material 78 by providing a fixing roller 77, a pressure roller 76 constituted to be mutually in press-contact and a heater 74 which heats the fixing roller 77 and passing the recording material 78 on which developer 79 of the unfixed toner image is formed through the nip part between the fixing roller 77 and the pressure roller 76 is provided with a removal means for removing the VOC. The removal means is constituted of the fixing roller 77 through the inside of which gas is passed by fans 93, 94 and to the inner surface of which photocatalyst is applied and the heater 74 which heats the fixing roller 77 using ultraviolet rays or visible light. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing device, and is particularly suitable for application to a technique for removing volatile organic compounds and odors generated in an image fixing process of an image forming apparatus such as a copying machine, a facsimile machine, and a printer.

  Conventionally, a toner image formed on a recording material using an electrophotographic process is subjected to heat fixing processing by a fixing device. On the other hand, recently, there are a wide variety of materials that can be used for image forming apparatuses, and it is desired to use new resin-coated paper as a material.

However, as a result of various experiments and examinations by the present inventor regarding the heat fixing treatment for such a new resin-coated paper, a small amount of volatile organic compound (hereinafter referred to as VOC) is obtained from the resin-coated paper. However, it has been found that the amount does not affect the human body.

As a technique for recovering the VOC, a technique described in Patent Document 1 is known. That is, Patent Document 1 describes a technique in which VOC is removed by filtration with an adsorption filter such as activated carbon disposed in a duct that exhausts the atmosphere of the fixing portion to the outside of the apparatus by a suction fan.
JP 2001-350375 A

  However, the VOC removal apparatus described in Patent Document 1 has the following problems.

  That is, a part of VOC that is supposed to be generated from the material at the time of fixing is diffused in the process until it enters the above-described duct or the process until it reaches the adsorption filter in the duct. There is a possibility that the VOC is diffused out of the apparatus from a gap of the cover or a louver formed in the cover due to natural convection in the apparatus.

  Accordingly, an object of the present invention is to provide a fixing device capable of efficiently removing volatile organic compounds.

In order to achieve the above object, the present invention provides:
A fixing rotator for thermally fixing the image on the recording material at the nip portion;
In a fixing device having heating means for heating the fixing rotator from the inside,
A fixing device comprising a removing unit that removes a volatile organic compound in a ventilation path in the fixing rotating body.

  According to the present invention, volatile organic compounds can be removed efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings of the following embodiments, the same or corresponding parts are denoted by the same reference numerals.

(First embodiment)
First, an image forming apparatus according to a first embodiment of the present invention will be described. FIG. 1 shows an image forming apparatus according to the first embodiment.

  As shown in FIG. 1, the image forming apparatus main body A is provided with a scanner unit B as an image reading unit that reads image information on the image surface of a book document. Further, an image forming unit C as an image forming unit is provided below the scanner unit B. A feeding / conveying section D is provided below the image forming section C.

  The scanner unit B includes a scanning light source 61, a platen glass 62, a document pressing plate 63 that can be opened and closed with respect to the image forming apparatus main body A, a first mirror 64, a second mirror 65, a third mirror 66, a lens 67, for example, a photoelectric sensor. It has a light receiving element 68 formed of a conversion element. Further, the scanner unit B has an image processing unit (not shown).

  The scanning system light source 61 and the first mirror 64 constitute a first mirror base M1. The second mirror 65 and the third mirror 66 constitute a second mirror base M2, which scans the image plane while moving along the scanning direction (arrow a direction). In addition, the movement state of the 1st mirror stand M1 and the 2nd mirror stand M2 is shown by the dotted line in FIG.

  Then, a book original such as a book, thick paper, or curled paper or a sheet-like original is placed on the platen glass 62 with the original side facing down, that is, the platen glass 62 side. Set in a pressed state. Thereafter, when the reading start key of the operation unit (not shown) is pressed by the user, the scanning system light source 61 scans the platen glass 62 in the direction of arrow a to illuminate the image surface of the document, and the reflected light ( Image information) is guided to the first mirror 64.

  Reflected light (image information) from the document guided to the first mirror 64 is projected onto the light receiving element 68 by the lens 67 through the second mirror 65 and the third mirror 66. The reflected light projected on the light receiving element 68 is read by the light receiving element 68, processed in an image processing unit (not shown), converted into an electric signal, and transmitted to a laser scanner 69 as an exposure unit in the image forming unit C. Is done.

  Here, the image forming apparatus main body A functions as a copying machine when a processing signal of an image processing unit (not shown) is input to the laser scanner 69, and functions as a printer when an output signal of a personal computer is input. Further, if a transmission signal from the facsimile machine of another machine is input or a processing signal of the image processing unit is sent to the facsimile machine of the other machine, it functions as a facsimile machine.

  On the other hand, a sheet cassette 21 is attached to the feeding / conveying section D below the image forming section C. The sheet cassette 21 is composed of a lower cassette 21a and an upper cassette 21b, thereby constituting one feeding unit.

  The recording material (sheet) accommodated in the lower cassette 21a or the upper cassette 21b is fed out by a pickup roller 22 that is a feeding rotating body. Thereafter, the recording materials are separated and fed one by one by the cooperative action of the feed roller 23 and the retard roller 24, and conveyed by the conveying roller pairs 25 and 26 or the conveying roller pair 27.

Then, the conveyed recording material is stopped for a predetermined time in order to absorb the variation between the recording materials in the pre-registration roller pair 28 and then conveyed by the rotation of the pre-registration roller pair 28. The recording material (sheet) is guided to the registration roller pair 11 by the conveyance roller pair 10 and is fed to the image forming unit C by the registration roller pair 11 in synchronization with the image forming operation.

  The image forming unit C includes a drum-type photosensitive member 1 as an image carrier, an exposure unit 2 as an image writing optical system, a developing unit 3, a primary charger 5, a transfer roller 6, and a cleaner unit 8. Has been.

  Then, a laser beam corresponding to the image information emitted from the laser scanner 69 is scanned on the surface of the photoreceptor 1 uniformly charged by the primary charger 5 by the polygon mirror 29 of the exposure device 2, and the electrostatic latent image. Is formed. The electrostatic latent image is developed as a toner image with toner attached thereto by the developing device 3. The toner image is transferred to the first surface (front surface) of the recording material by the transfer roller 6 with respect to the recording material conveyed in synchronization with the rotation of the photosensitive member 1 by the registration roller pair 11.

  A conveyance guide 19 as a guide unit, a fixing device 7 as a fixing unit, discharge roller pairs 12 and 14, and a flapper 15 are disposed downstream of the image forming unit C in the recording material conveyance direction. The recording material onto which the toner image has been transferred is guided by a transport guide 19 from a transfer section E composed of the photoreceptor 1 and the transfer roller 6 and transported to the fixing device 7 where it is heated and pressurized to cause the toner image to be on the surface. To be established.

  The recording material that has been subjected to the fixing process is conveyed in the discharge direction and is disposed above the image forming unit C by the discharge roller pair 12 and 14, and the upper surface of the discharge tray (stacking member) 13 that functions as an upper surface cover. It is discharged and stacked on the (recording material stacking surface). The recording material is discharged onto the paper discharge tray 13 in a so-called face-down manner with the image forming surface facing downward.

  Further, when a toner image is formed on both surfaces of a recording material, the following is performed. That is, the recording material is conveyed by the discharge roller pair 12 and 14 after passing through the fixing device 7. Immediately after the trailing edge of the recording material passes through the flapper 15, the recording roller is reversed by rotating the discharge roller pairs 12 and 14 while holding the recording material, and is temporarily placed on the recording material double-sided tray 16. Thereafter, the recording material is conveyed by the pre-registration roller pair 28 and the conveyance roller pair 10 and reaches the registration roller pair 11. The reversed recording material is configured such that a toner image is formed on the second surface (back surface) thereof by the same method as described above, and then discharged and stacked on the paper discharge tray 13.

(Fixing device)
Next, the fixing device 7 according to the first embodiment will be described. Various fixing devices have been devised as the fixing device 7, but at present, a heat fixing device is mainly used. As this heat fixing apparatus, there is an apparatus of a type that allows the image support material to pass through the furnace without contacting the heat source side. Of these types of heat fixing devices, a heat roller fixing device using a pair of rollers is often used because of its high thermal efficiency. Therefore, the basic configuration of the heat roller fixing device will be described by taking as an example the case of using a roller having a heat source on the image forming side. FIG. 2 shows the fixing device 7 provided in the image forming apparatus according to the first embodiment of the present invention.

As shown in FIG. 2, in the fixing device 7, a heater 74 such as a halogen heater as a heating unit that is a heat source is provided inside a fixing roller 77 as a fixing rotating body. The surface layer is made of an elastic body 75 such as rubber. Further, the fixing roller 77 and a pressure roller 76 that is pressed toward the fixing roller 77 by a pressure unit (not shown) form a pair that forms an appropriate nip. The pressure roller 76 and the fixing roller 77 are driven by a drive unit (not shown) from the main body of the image forming apparatus and rotate in the direction of the arrow in FIG. During operation, the surface of the fixing roller 77 is maintained at a substantially constant temperature by a thermistor (not shown) or the like.

  A transfer material 78 of an image support material that supports an unfixed image as an unfixed toner image formed by the developer 79 in the latent image forming unit is nipped and conveyed between the fixing roller 77 and the pressure roller 76. At this time, the unfixed toner image is fixed to the transfer material 78 by the heating by the heater 74 as a heat source and the pressure between the pressure roller 76 and the fixing roller 77.

  The fixing roller 77 is configured such that the coating resin layer 71 is the uppermost layer on the cored bar 73 via a primer layer 72 as an adhesive to prevent the developer from adhering. As this coating resin layer 71, silicone rubber, a fluororesin film, or a tube is used. Examples of the fluororesin material preferably used as the material for the resin layer include perfluoroalkoxide (PFA), polytetrafluoroethylene (PTFE), hexafluoropropylene copolymer (FEP), and the like.

  Further, the fixing device 7 is provided with a release agent coating unit. This release agent application means includes a web pressure roller 81, a take-up roller 84, and a web supply roller 85. The web supply roller 85 is wound with a cleaning web 80 impregnated with a release agent such as silicone oil. The take-up roller 84 is configured to take up the cleaning web 80 that is pulled out from the web supply roller 85.

  The web pressure roller 81 presses the cleaning web 80 toward the fixing roller 77. The cleaning web 80 is fed little by little in accordance with the copying operation, and the fixing roller 77 is rotated to apply a release agent to the fixing roller 77 and remove the developer attached on the fixing roller 77. Note that a so-called cleaningless fixing device is not provided with a release agent coating unit, and the adhesion of the developer is prevented only by the release property of the surface layer of the fixing roller 77.

  This release agent application means impregnates an application member with a release agent so as to contact the fixing roller 77. Examples of the release agent coating means include a cleaning web, a felt pad, a felt roller, etc. impregnated with a release agent, a poreflon provided with a permeable membrane from the oil pan to the bottom of the release agent container, an application roller, etc. The thing applied through can be mentioned. There is also a method of applying a release agent to the elastic body of the pressure roller. An oil such as silicone is used as the release agent.

  In the fixing device 7, a large amount of heat is released from the heater 74, which is a heat generation source, and the image input device and the photosensitive drum around the fixing device 7 and the surrounding members are heated. Therefore, in order to prevent the deformation of the optical member and the fusion of the developer due to the heat, the fixing device 7 is provided with a heat insulating cover 82.

  An inner discharge upper guide 88 and an inner discharge lower guide 89 for conveying the transfer material 78 downstream are provided on the downstream side of the fixing nip constituting the fixing portion, and the downstream inner discharge is provided. It is conveyed to a pair of paper rollers 86 and 87. Here, the volatile organic compound released from the transfer material 78 that has passed through the fixing nip includes a fixing roller 77 as a fixing rotator, a pressure roller 76, an inner discharge upper guide 88, an inner discharge lower guide 89, and an inner discharge. It stays in a space 90 surrounded by the pair of paper discharge rollers 86 and 87.

  Next, a configuration in which a volatile organic compound staying on the downstream side of the fixing nip (downstream of the conveyance path) is passed inside the fixing device 7 will be described. FIG. 3 shows a fixing unit of the fixing device according to the first embodiment.

  That is, as shown in FIG. 3, the fixing roller 77, the pressure roller 76, the inner discharge upper guide 88, the inner discharge lower guide 89, and one end portion of the space 90 surrounded by the inner discharge roller pair 86, 87 are provided. A duct 91 is provided. By this duct 91, the air in the space 90 is guided into the fixing roller. A fan 93 is provided in the duct 91. When the fan 93 is rotated, the gas (mainly air) in the space 90 passes through the fixing roller 77 as shown by an arrow in FIG.

  For example, titanium oxide as a photocatalyst is dispersedly supported on the inner surface of the fixing roller 77. When the photocatalyst is irradiated with light such as ultraviolet light or visible light emitted from a heater 74 as a heating unit disposed inside the fixing roller 77, active oxygen is generated from titanium oxide. Generation of this active oxygen makes it possible to decompose and remove adsorbed or floating VOC (volatile organic compound) and odor components.

  As described above, the volatile organic compound removing unit includes the fixing roller 77 and the roller heated by the heater 74, that is, the photocatalyst dispersed and supported in the fixing roller 77.

  Further, members that carry the adsorbent are disposed on the inner surface of the duct 91 and the inner surface 83 of the fixing cover. This makes it possible to improve the ability to remove VOC (volatile organic compound) by adsorbing VOC generated during fixing to the member. Here, the adsorbent is a substance that physically or chemically adsorbs a substance in a gas phase by an interface. Specifically, for example, silica gel, alumina, titania, activated carbon, activated carbon fiber, porous glass, porous alumina, porous metal oxides such as zirconia and magnesia, porous ceramics, zeolite, carion, montmorillonite And clay minerals such as vermiculite. These substances may be used alone or in combination. The adsorbent preferably has a form with a large surface area, and the adsorbent support preferably has a form in which the surface area of the surface carrying the adsorbent can be as large as possible.

(Second Embodiment)
Next, a fixing device according to a second embodiment of the present invention will be described. FIG. 4 shows a fixing portion of the fixing device 7 according to the second embodiment.

  That is, the fixing portion of the fixing device according to the second embodiment is surrounded by the fixing roller 77, the pressure roller 76, the inner discharge upper guide 88, the inner discharge lower guide 89, and the inner discharge roller pairs 86 and 87. A space 90 is formed. As shown in FIG. 4, a duct 91 is provided at one end of the space 90 so that air in the space 90 is guided into the fixing roller.

  A duct 92 is provided at the other end of the space 90 so that the air inside the fixing roller 77 is guided to the space 90. The ducts 91 and 92 are provided with fans 93 and 94, respectively. Then, by rotating these fans 93 and 94, the gas in the space 90 and the inside of the fixing roller 77 is circulated in a predetermined direction as indicated by an arrow.

  Further, as in the first embodiment, titanium oxide is dispersedly supported on the inner surface of the fixing roller 77 as a photocatalyst. When the photocatalyst is irradiated with light from the heater 74 disposed inside the fixing roller 77, active oxygen is generated from the titanium oxide. This makes it possible to reduce adsorbed or floating VOCs.

Next, a configuration in which a volatile organic compound staying on the downstream side of the fixing nip in the fixing unit is passed inside the fixing device 7 will be described.

  That is, a duct 91 is provided at one end of a space 90 surrounded by the fixing roller 77, the pressure roller 76, the inner discharge upper guide 88, the inner discharge lower guide 89, and the inner discharge roller pair 86 and 87. The air in the space 90 is guided to the inside of the fixing roller 77.

  In addition, a duct 92 is provided at the other end of the space 90 and is configured to guide the air inside the fixing roller 77 to the space 90. The ducts 91 and 92 are provided with fans 93 and 94, respectively. By rotating these fans 93 and 94, the gas (mainly air) inside the space 90 and the fixing roller 77 can be circulated in the direction of the arrow in FIG.

  On the inner surface of the fixing roller 77, titanium oxide is dispersedly supported as a photocatalyst. When the photocatalyst is irradiated with light from the heater 74 disposed inside the fixing roller 77, active oxygen is generated from the titanium oxide, thereby adsorbing or floating VOC (volatile organic compound) and odor components. Decomposed and removed.

  As described above, according to the fixing device according to the second embodiment, the gas inside the fixing device 7 can be circulated without leaking out of the fixing device 7. Thereby, the decomposition | disassembly removal capability of VOC (volatile organic compound) and an odor component can be improved further.

  In the above-described embodiment, an example in which the present invention is applied to a fixing device that heats and pressurizes an unfixed toner image on a recording material has been described, but the recording material may be used for adjusting the glossiness of an image. The present invention can also be applied to an apparatus for heating a formed toner image. Specifically, in the configuration in which, for example, two fixing devices (image heating devices) are provided, and the toner image is fixed on the recording material in the first fixing device, the toner image is fixed by the second fixing device. The invention can be applied to both of these fixing devices (image heating devices).

  In addition, an air passage means for passing the gas downstream of the pressure contact portion, which is a nip portion, is passed through the fixing device, and a volatile organic compound removing means is provided in the air passage means to generate the nip portion. Volatile organic compounds can be reliably processed inside the fixing device. Therefore, it is possible to prevent the organic compound from diffusing inside and outside the image forming apparatus and to suppress unpleasant odor. Further, by preventing diffusion of the volatile organic compound into the image forming apparatus, contamination of the volatile organic compound in a charger such as a corona charger provided in the image forming apparatus can be prevented. As a result, corona discharge can be stabilized and the latent image carrier can be uniformly charged, so that density unevenness and vertical stripes can be reduced and black spots and the like can be prevented.

  The air passing means is constituted by a fan, and the fan is configured to allow gas to pass inside the fixing device. By adopting this configuration and allowing air to pass through the fixing device by a fan, the volatile organic compound can be passed through the fixing device, so that the volatile organic compound can be removed more easily by the removing means. It becomes possible.

Further, as the air passing means, it is possible to adopt a configuration in which a gas (mainly air) on the downstream side of the nip portion is fed into the fixing body. More preferably, as the air passing means, gas (mainly air) on the downstream side of the nip part is fed into the fixing rotator, and gas (mainly air) exhausted from the fixing rotator is sent to the downstream side of the nip part. It is possible to adopt a configuration in which gas is circulated by flowing. According to this configuration, the gas on the downstream side of the nip portion of the fixing rotating body is supplied into the fixing body by the air passing means. Therefore, the gas can be circulated in the fixing device by flowing the gas exhausted from the inside of the fixing body to the downstream side of the nip portion. Therefore, the high-concentration volatile organic compound immediately after fixing can be circulated without being released from the sheet conveying port to the outside of the fixing device, and the volatile organic compound can be removed more reliably.

  Further, the volatile organic compound removing means includes a heating means for heating using light such as visible light or ultraviolet light, and a photocatalyst constituted by, for example, titanium oxide being dispersedly supported on the inner surface of the fixing body. Has been configured. As a result, there is no need to newly provide a light emitting means for activating the photocatalyst, and the conventional heating means can also be used as the light emitting means, thereby suppressing the complexity of the structure and simplifying the structure. can do. Furthermore, by using a photocatalyst, even if high-concentration volatile organic compounds are removed, the reduction in the removal capability can be suppressed, so that a means for removing volatile organic compounds that can be reused by simple cleaning is obtained. Can do.

1 is a cross-sectional view illustrating an image forming apparatus according to a first embodiment of the present invention. 1 is a cross-sectional view illustrating a fixing device according to a first embodiment of the present invention. 1 is a perspective view showing a fixing device according to a first embodiment of the present invention. It is a perspective view which shows the fixing device by the 2nd Embodiment of this invention.

Explanation of symbols

71 Coating resin layer 72 Primer layer 73 Core metal 74 Heater 75 Elastic body 76 Pressure roller 77 Fixing roller 78 Transfer material 79 Developer 80 Cleaning web 81 Web pressure roller 82 Heat insulation cover 83 Inner surface 84 Winding roller 85 Web supply roller 86 , 87 Inner sheet discharge roller pair 88 Inner sheet discharge upper guide 89 Inner sheet discharge lower guide 90 Space 91, 92 Duct 93, 94 Fan M1 First mirror stand M2 Second mirror stand

Claims (5)

A fixing rotator for thermally fixing the image on the recording material at the nip portion;
In a fixing device having heating means for heating the fixing rotator from the inside,
A fixing device comprising: a removing unit that removes a volatile organic compound in a ventilation path in the fixing rotating body.   The fixing device according to claim 1, wherein the removing unit includes a photocatalyst that removes a volatile organic compound using light of the heating unit.   The fixing device according to claim 2, wherein the photocatalyst is applied to an inner surface of the fixing rotating body.   The fixing device according to claim 2, wherein the photocatalyst includes titanium oxide.   5. The fixing device according to claim 1, further comprising a circulating unit that circulates air in the vicinity of the nip portion through a ventilation path in the fixing rotating body.

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