JP2015138188A - Fixing device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a suspended substance such as a chemical substance generating from an end surface of a fixing roller from dispersing inside or around a fixing device, and to execute collection and storage of the suspended substance by a filter and the like easily.SOLUTION: An intake member 71 includes a first opening 71a opening toward a nip exit space 201 interposed between separation members 131, 141, and also includes an opening 71b which is toward an axial direction end surface of a pressure roller 21. The opening 71a opens toward the nip exit space 201 which is interposed between a fixation separation member 131 and a pressure separation member 141, sucks air containing a suspended substance H staying in the nip exit space 201 and prevents it from dispersing. The opening 71b opens toward the end surface in the axial direction of the pressure roller 21, sucks the air containing the suspended substance E such as siloxane gas generating from the end surface in the axial direction of the pressure roller 21 and prevents the suspended substance E from dispersing.

Description

  The present invention relates to a fixing device used in an electrostatic recording image forming apparatus such as a copying machine, a facsimile machine, and a printer, and an image forming apparatus equipped with the fixing device.

  In an image forming apparatus, an unfixed toner image is transferred to a recording material sheet, printing paper, photosensitive paper, electrostatic recording paper, etc. by an image transfer method or a direct method by an image forming process such as electrophotographic recording, electrostatic recording, and magnetic recording. Formed on recording material. As a fixing device for fixing an unfixed toner image, a contact heating method fixing device such as a heat roller method, a film heating method, and an electromagnetic induction heating method is widely used. In such a fixing device, a pair of fixing rotators (such as a fixing roller and a fixing belt) are pressed against each other to form a fixing nip, and heat and pressure are applied to a recording medium passing through the fixing nip. Unfixed toner is fixed.

  In such a fixing device, various troubles occur due to the diffusion of various floating substances generated in the fixing process to the inside or the peripheral devices of the fixing device. Examples of the floating substance include moisture generated from the recording medium by heating when passing through the fixing nip, wax generated from the toner, and volatile chemical substance generated from the end surface of the fixing roller that has become high (see Patent Document 1). It is.

  Among these floating substances, it is known that moisture, wax, etc. may stay in the air at the exit of the fixing nip and cause various problems due to the diffusion of this air. For example, when printing is performed by rapidly starting up the fixing device from room temperature, other members such as the fixing nip through which the recording medium passes are at a high temperature, but other fixing devices and peripheral image forming devices are configured. The temperature of the member to be performed is often low. When air flows into the low-temperature member from the fixing nip outlet and is cooled, water droplets and wax adhere to the member due to condensation. For example, when condensation occurs in the conveyance path of the recording medium, a streak image may occur due to water droplets adhering to the recording medium, or the recording medium may be deformed. Further, when wax adheres to a member that transports the recording medium, the transportability may change and a transport jam may occur.

  As a temperature sensor used to detect the temperature of the fixing device, a temperature detection sensor that detects the temperature of an object by receiving infrared rays such as a thermopile is used. With this type of sensor, when water droplets or wax due to condensation adheres to the light receiving part, the infrared light receiving state changes and an error occurs in the detected temperature. If the temperature of the fixing device is detected and controlled using the temperature detection sensor in such a state, the temperature of the fixing device cannot be controlled as a result, and there is a possibility that a fixing failure or the like may occur.

  Further, as a chemical substance generated from the end face of the fixing roller, an elastic resin layer provided with a thickness in order to improve fixing quality is known. When a high temperature state is reached, a part of the resin component volatilizes and is generated as a chemical substance from the portion exposed on the end face of the fixing roller. Further, when the elastic resin layer is a foamed elastic body, a chemical substance is generated from the foam wall of the foamed portion and ejected from the end surface of the fixing roller, so that the amount of chemical substance generated is larger than that of the non-foamed elastic body. The generated chemical substance causes various problems depending on its components. For example, siloxane gas generated from silicone rubber causes malfunction due to contamination of electrical circuits and relay contacts, and therefore, it is necessary to suppress diffusion outside the fixing device and the image forming apparatus.

  In order to prevent the above problems, a removal filter, a storage space, and the like are provided so that the air at the fixing nip outlet containing a large amount of moisture and wax and the air at the end surface of the fixing roller are not diffused into and out of the fixing device or the image forming apparatus. Many techniques for controlling the airflow in the fixing device so as to be guided to an appropriate path have been proposed (see, for example, Patent Documents 2 to 4).

  Patent Document 1 proposes a fixing device that exhausts floating substances generated from the roller end. The cap that covers the space at the roller end portion forms an air flow that is exhausted from the gap between the roller end portion and the cap to the predetermined path through the space at the roller end portion. However, in this fixing device, the positional relationship of the opening (the gap between the roller end and the cap) for introducing air into the roller end with respect to the fixing nip outlet is not controlled. Therefore, the suspended matter generated at the nip outlet cannot be exhausted to a predetermined path.

  Japanese Patent Application Laid-Open No. 2005-228561 proposes a technique in which a duct for sucking air in the fixing device is provided on the upper portion of the fixing device. However, in such a configuration, air is sucked at a position away from the fixing nip outlet and the fixing roller end face. For this reason, it is difficult to prevent the diffusion of the floating substance in the fixing device, and the suction efficiency of the air containing the problematic floating substance is poor.

  Accordingly, the present invention provides a fixing device having a configuration in which suspended substances are prevented from diffusing into or around the fixing device and can be easily collected and stored by a filter or the like, and an image forming apparatus including the fixing device. For the purpose.

  The fixing device according to the present invention includes a fixing rotator, a pressure rotator that is in pressure contact with the fixing rotator and forms a fixing nip between the fixing rotator, and the pressure rotator is the pressure rotation. A recording medium conveyed in the first conveyance direction in the conveyance direction of the recording medium in the fixing nip by rotating in the first rotation direction among the rotation directions of the body, and conveyed in the first conveyance direction In the fixing device, comprising: the recording medium carried out from the fixing nip; and a first and second pair of separating members installed so as to face both the outer peripheral surface of the fixing rotating body. A first opening is provided toward a nip exit space of the fixing nip sandwiched between the first separation member and the second separation member, and a second opening toward the axial end surface of the pressure rotator. It has an intake member with an opening. To.

  According to the present invention, it is possible to easily form an air flow for discharging floating substances. The airflow suppresses the diffusion of floating substances such as moisture, wax generated from the recording medium and toner at the fixing nip exit, and chemical substances generated from the end face of the fixing roller into or around the fixing device. Thereby, collection and storage by a filter or the like can be easily performed.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus that can use a fixing device of the present invention. FIG. 2 is a cross-sectional view illustrating an outline of a fixing device at an axial center of a fixing roller. FIG. 3 is a schematic view showing the fixing device viewed from the direction of arrow A in FIG. 2 from the fixing nip exit side. It is a figure showing the shape of an intake member. It is a figure same as the above. FIG. 6 is a diagram illustrating a positional relationship between an opening of an intake member and a nip outlet space at an axial end portion of the fixing roller, and an air flow through which the opening sucks air in the nip outlet space. It is a figure same as the above. FIG. 6 is a cross-sectional view illustrating an outline of a fixing device according to a second embodiment of the present invention. It is a figure same as the above.

An embodiment of the present invention will be described.
The present invention provides a predetermined path for air staying in both the vicinity of the fixing nip outlet and the vicinity of the fixing roller end face without newly providing a motor and a rotating shaft for generating an air flow in the fixing device separately from the fixing roller. It is possible to easily form the airflow discharged by This air flow suppresses the diffusion of floating substances such as moisture, wax generated from the recording medium and toner at the exit of the fixing nip, and chemical substances generated from the end face of the fixing roller into or around the fixing device. It is characterized by the fact that it can be easily collected and stored.

The characteristics of the present invention will be described below in detail with reference to the drawings.
A configuration example of an image forming apparatus that can use the fixing device of the present invention will be described with reference to FIG.
The image forming apparatus shown in FIG. 1 is a color printer that uses a tandem system in which image forming units that form a plurality of color images are juxtaposed along a belt extending direction. However, the present invention is not limited to this method, and other methods can be adopted. It is also possible to target not only printers but also copying machines and facsimile machines.

  In FIG. 1, an image forming apparatus 100 is a tandem in which photosensitive drums as image carriers capable of forming images as images corresponding to colors separated into yellow, cyan, magenta, and black are arranged in parallel. Structure is adopted. The visible image formed on each of the photoconductive drums 4Y, 4C, 4M, and 4Bk is transferred to the transfer belt 30 that is an intermediate transfer body that can move in the direction of the arrow in the drawing while facing the photoconductive drums 4Y to 4Bk. The next transfer process is executed, and the respective images are superimposed and transferred. The image primarily transferred to the transfer belt 30 is then collectively transferred by performing a secondary transfer process on the recording paper S such as a recording sheet. Note that an endless belt is used as the transfer belt 30 and is simply referred to as the transfer belt 30 below. In addition, if it is not necessary to specify the colors of the photosensitive drums 4Y to 4Bk, they are simply referred to as the photosensitive drum 4.

  Around each photosensitive drum 4, an apparatus for image formation processing is arranged according to the rotation of the photosensitive drum 4. A description will be given of the photosensitive drum 4Bk that performs black (Bk) image formation. A charging device, a developing device, a primary transfer roller 31, and a cleaning device that perform an image forming process along the rotation direction of the photosensitive drum 4Bk are arranged. For the writing performed after charging, the optical writing device 9 is used. In the transfer to the transfer belt 30, the visible image formed on each photoconductive drum 4 is transferred to the same position on the transfer belt 30 while the transfer belt 30 moves in the arrow direction. For this reason, voltage application is performed by the primary transfer roller 31 disposed so as to face each of the photosensitive drums 4Bk with the transfer belt 30 interposed therebetween. The application of voltage by the primary transfer roller 31 is performed with the timing shifted in correspondence with the position of the photosensitive drum 4 from the upstream side toward the downstream side in the moving direction of the transfer belt 30.

  The image forming apparatus 100 includes four image stations that perform image forming processing for each color. Each image station includes a transfer belt unit 200 that is disposed opposite to the photosensitive drum 4 and includes a transfer belt 30 and a primary transfer roller 31. Further, a secondary transfer roller 36 is provided as a transfer roller disposed as opposed to the transfer belt 30 and driven by the transfer belt 30 as a transfer member. Further, a cleaning device 35 disposed opposite to the transfer belt 30 for cleaning the surface of the transfer belt 30, and an optical writing device 9 serving as an optical writing device disposed opposite to these four image stations. have.

  The optical writing device 9 is equipped with a semiconductor laser as a light source, a coupling lens, an fθ lens, a toroidal lens, a folding mirror, a rotating polygon mirror as a deflecting means, and the like. Then, writing light corresponding to each color is emitted to each photosensitive drum 4 to form an electrostatic latent image on the photosensitive drum 4.

  The image forming apparatus 100 includes a sheet feeding device 130 as a paper feeding cassette on which a recording medium P conveyed between the photosensitive drum 4 and the transfer belt 30 is loaded. Further, the recording medium P conveyed from the sheet feeding device 130 is directed to a transfer portion between each photosensitive drum 4 and the transfer belt 30 at a predetermined timing in accordance with the toner image formation timing by the image station. A registration roller pair 120 is provided. Further, a sensor (not shown) that detects that the leading edge of the recording medium P has reached the registration roller pair 120 is provided.

  The image forming apparatus 100 includes a fixing device 20 as a roller fixing type fixing unit for fixing the toner image to the recording paper S on which the toner image is transferred. Further, a discharge roller 140 that discharges the fixed recording medium P to the outside of the main body of the image forming apparatus 100 is provided. In the figure, reference numeral 14 denotes a paper discharge tray, which is disposed on the top of the main body of the image forming apparatus 100 and stacks the recording medium P discharged to the outside of the main body of the image forming apparatus 100 by the paper discharge roller 140. Below the paper discharge tray 14, toner bottles 9Y, 9C, 9M, and 9k filled with toners of yellow, cyan, magenta, and black are provided.

  In addition to the transfer belt 30 and the primary transfer roller 31, the transfer belt unit 200 includes a driving roller and a driven roller around which the transfer belt 30 is wound.

  The driven roller also has a function as tension urging means for the transfer belt 30. Therefore, the driven roller is provided with a biasing means using a spring or the like. The transfer belt unit 200, the primary transfer roller 31, the secondary transfer roller 36, and the cleaning device 35 constitute a transfer device.

  The sheet feeding device 130 is disposed at the lower part of the main body of the image forming apparatus 100, and includes a feeding roller 110 as a paper feeding roller that contacts the upper surface of the uppermost recording medium P. When the feeding roller 110 is driven to rotate counterclockwise, the uppermost recording paper S is fed toward the registration roller pair 120.

  Although not shown in detail, the cleaning device 35 provided in the transfer device has a cleaning brush and a cleaning blade disposed so as to face and contact the transfer belt 30. Then, foreign matter such as residual toner on the transfer belt 30 is scraped and removed by a cleaning brush and a cleaning blade, and the transfer belt 30 is cleaned. The cleaning device 35 also has a discharge means (not shown) for carrying out and discarding the residual toner removed from the transfer belt 30.

<Embodiment 1>
FIG. 2 is a cross-sectional view schematically showing the fixing device at the axial center of the fixing roller 11.
A fixing rotator (fixing roller 11) and a pressure rotator (pressure roller 21) face each other in the fixing device, and the pressure roller 21 is pressed against the fixing roller 11 to form a fixing nip 41. Is done. As the pressure roller 21 rotates in the R2 direction, a driving force due to friction is transmitted to the fixing roller 11 in the fixing nip 41, and as a result, the fixing roller 11 is driven to rotate in the R1 direction. The sheet-like recording medium P on which an unfixed toner image is placed is sandwiched between the fixing roller 11 and the pressure roller 21 in the fixing nip 41 and is conveyed in the conveying direction T by the respective rotations. Simultaneously with conveyance, the toner image is fixed on the recording medium P by applying heat and pressure from the fixing roller 11 and the pressure roller 21 to the toner image on the recording medium P in the fixing nip 41.

  In this embodiment, a heating source of heat supplied to the toner image at the fixing nip 41 is not shown. Examples of the heating source include a radiation heater, an electromagnetic induction heating coil, and a resistance heating element. These heating sources heat the fixing roller 11 to efficiently supply heat to the toner image.

  The fixing roller 11 preferably has a diameter of 15 to 300 mm in consideration of a heat capacity and a space for accommodating a member inside the belt. The fixing roller 11 is composed of a cored bar portion 11a and an elastic layer 11b in order from the inner peripheral side, and a thin film surface layer is generally laminated on the surface although not shown. However, when the performance requirement regarding the image quality is not high, a two-layer structure of the cored bar portion 11a and the surface layer may be used except for the elastic layer 11b.

A metal material such as stainless steel and aluminum having high rigidity is desirably used as the core metal portion 11a, and an elastic material such as silicone rubber is desirably used as the elastic layer 11b. Even when the surfaces of the recording medium P and the fixing roller 11 are uneven due to the deformation of the elastic layer 11b, it is possible to suppress uneven pressure and thermal conductivity in the fixing nip 41, and the toner fixing quality is improved. improves. For the surface layer, a material having high releasability of toner and recording medium is used. For example, PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), PTFE (tetrafluoroethylene resin), polyimide, polyetherimide, PES ( It is desirable to use polyether sulfide).
The pressure roller 21 is preferably constituted by a cored bar portion 21a formed of a metal material and an elastic layer 21b formed of an elastic material such as silicone rubber or foamed silicone rubber. It is particularly preferable to employ foamed silicone rubber having high heat insulation. Although not shown, by providing a thin film surface layer formed of a fluorine-based resin such as PFA or PTFE on the outer peripheral portion of the elastic layer, the releasability of the toner and the recording medium can be improved.

  The non-contact temperature sensor 121 detects the surface temperature of the temperature detection region 11c by receiving infrared rays radiated from the temperature detection region 11c of the fixing roller 11 by a light receiving unit 121a provided on the surface facing the fixing roller 11 side. . By controlling the heating amount of the fixing roller 11 by the heating source in accordance with the surface temperature, the temperature of the fixing roller 11 and the fixing nip 41 is controlled to improve the fixability of the toner image on the recording medium P. .

  A fixing separation member 131 and a pressure separation member 141 are installed at positions facing the fixing roller 11 and the pressure roller 21 on the conveyance outlet side of the recording medium P in the fixing nip 41, respectively. The interval between the fixing separation member 131 and the surface of the fixing roller 11 and the interval between the pressure separation member 141 and the surface of the pressure roller 21 are for preventing the recording medium P from being wrapped around the fixing roller 11 and the pressure roller 21. , Is set very fine. Thereby, even when the recording medium P is wrapped around the fixing roller 11 or the pressure roller 21 and conveyed, the leading end of the recording medium P is caught by the fixing separation member 131 or the pressure separation member 141. The recording medium P can be transported in the transport direction T.

  By being heated when passing through the fixing nip 41, a part of the moisture contained in the recording medium P and wax contained in the toner image is vaporized and generated as a floating substance H at the outlet of the fixing nip 41. At this time, the fixing separation member 131 and the pressure separation member 141 serve as walls, and most of the air containing the suspended matter H stays in the nip outlet space 201.

  FIG. 3 is a schematic diagram showing the fixing device from the outlet side of the fixing nip 41 (indicated by an arrow A in FIG. 2), and illustrates the fixing roller 11 so that the axial direction of the fixing roller 11 is horizontal. However, in order to facilitate understanding, only the contour of the pressure separating member 141 is shown by a broken line. The fixing separation member 131 is in contact with the fixing roller 11 at the end in the axial direction, thereby increasing the positioning accuracy with respect to the surface of the fixing roller 11.

  The cored bar part 11a of the fixing roller 11 is fixedly supported by the frames 91 and 92, and the cored bar part 21a of the pressure roller 21 is rotatably supported by the frames 111 and 112 via bearings or the like. As the frames 111 and 112 move relative to the frames 91 and 92, the pressure roller 21 moves toward and away from the fixing roller 11.

  The drive gear 81 is fixed to the cored bar portion 21a of the pressure roller 21, and the pressure roller 21 is rotated by driving the drive gear 81 from the outside. The driving torque is transmitted to the fixing roller 11 through the fixing nip 41, so that the fixing roller 11 is driven to rotate.

  The fixing separation member 131 and the pressure separation member 141 are configured to be wider than the sheet passing width W through which the recording medium P passes in the fixing nip 41. The pressure roller 21 has a range in which the core layer 21a is exposed without the elastic layer 21b at both ends in the axial direction, and an intake member 71 that sucks air in the nip outlet space 201 around the core bar 21a. 72, the intake member 71 is fixed to the frame 111.

Details of the intake member 71 will be described in detail with reference to FIGS. The same applies to the intake member 72.
4 and 5 are views showing the shape of the intake member 71. FIGS. 6 and 7 show the positional relationship between the opening 71a of the intake member 71 and the nip outlet space 201 at the axial end of the fixing roller 11, and the opening. 71a is a diagram showing an air flow that sucks air in the nip outlet space 201. FIG. However, peripheral members such as the pressure roller 21 are also shown in FIGS.

  A hole 71d into which the cored bar 21a of the pressure roller 21 is inserted is formed in the center of the intake member 71. In addition, an opening 71a facing the nip outlet space 201 and an opening 71b facing the end face of the pressure roller 21 are provided, and an opening 71c for exhausting air taken in from the openings 71a and 71b is provided. Yes. In the present embodiment, the opening 71a and the opening 71b are one continuous opening, thereby preventing the intake member 71 from having a complicated shape.

  One opening 71 a opens toward the nip outlet space 201 sandwiched between the fixing separation member 131 and the pressure separation member 141, and sucks in air containing suspended solids H remaining in the nip outlet space 201. Thus, diffusion of the suspended substance H to the fixing device and the image forming apparatus can be prevented. The opening 71 a protrudes from the axial end surface of the pressure roller 21 in the direction from the rotation shaft of the pressure roller 21 toward the nip outlet space 201. As a result, the air containing the suspended matter H staying in the nip outlet space 201 without being blocked by the air flow at the axial end face of the pressure roller 21 can be reliably sucked. Further, since the opening 71a protrudes only in the direction from the rotation shaft of the pressure roller 21 toward the nip outlet space 201, the intake efficiency for intake of air containing the suspended matter H is enhanced.

  The other opening 71 b opens toward the end surface in the axial direction of the pressure roller 21. From the end surface of the pressure roller 21 in the axial direction, for example, a floating substance E such as siloxane gas is generated from the elastic layer 21b. When the opening 71b sucks air containing the floating substance E, the diffusion of the floating substance E to the fixing device and the image forming apparatus can be prevented.

  The other opening 71 c communicates with the exhaust path F through a hole 111 c provided in the frame 111.

  Then, the air flow generating member 151 provided on the exhaust path F side causes the openings 71a and 71b to inhale the air near the nip outlet space 201 and the end surface in the nip axial direction, and generate an air flow that is exhausted from the opening 71c. . Note that the air intake operation by the airflow generation member 151 does not necessarily have to be always performed, and the air intake operation may be switched on and off depending on, for example, the temperature of the pressure roller 21 and the sheet passing state of the recording medium P. Since the difference between the inner diameter of the hole 71d of the intake member 71 and the outer diameter of the cored bar portion 21a of the pressure roller 21 is set to be small, the flow rate of the airflow through the hole 71d can be ignored. In addition, you may give a seal | sticker etc. as needed.

  The opening 71b is provided so as to cover the end surface of the pressure roller 21 in the axial direction, and the gap G is set minutely. Thereby, the intake flow rate when the opening 71b inhales the air containing the suspended substance E can be reduced. The intake flow rate of the opening 71a is an amount obtained by subtracting the intake flow rate of the opening 71b from the exhaust flow rate of the opening 71c. Therefore, by reducing the flow rate at the opening 71b, it is possible to secure a sufficient intake flow rate necessary for the opening 71a to suck in the air in the nip outlet space 201 containing the suspended matter H.

  Of the intake member 71, the first opening 71 a and the second opening 71 b are the only openings that open toward the fixing nip 41, and only the first opening 71 a is the rotation shaft of the pressure roller 21. It protrudes in the direction toward the nip outlet space 201. By adopting such a configuration, the second opening 71b appropriately restricts the flow rate of sucking the floating substance E generated from the axial end surface of the pressure roller 21 by the gap G, and the first opening 71a It is possible to increase the intake efficiency of intake of air containing the suspended matter H staying in the outlet space 201.

  By securing a filter and a storage space in the exhaust path F, it is possible to prevent the floating substances H and E collected by the intake member 71 from diffusing into and out of the fixing device and the image forming apparatus. Can be prevented.

  In this embodiment, no opening of the intake member is provided on the end surface in the axial direction of the fixing roller 11. In the fixing roller 11, the thickness of the elastic layer 11b is set to be thin for the purpose of shortening the startup time. For this reason, compared with the elastic layer 21b of the pressure roller 21, the total amount of floating substances generated from the end face is small. However, if there is a concern about the influence of diffusion of floating substances on the fixing device and the image forming apparatus, an opening is provided on the end face of the fixing roller 11 as well as the end face of the pressure roller 21 to suck in the floating substance. good.

<Embodiment 2>
8 to 9 are sectional views schematically showing the fixing device according to the second embodiment of the present invention. The points that are not particularly described in the present embodiment are the same configurations and functions as those in the first embodiment.

  In the present embodiment, a fixing roller 11 having a small heat capacity is used instead of the fixing roller 11 in the first embodiment. As a result, the amount of heat required to heat the fixing roller 11 is reduced, and a rapid start-up of the fixing device is realized. In such a fixing device, immediately after the recording medium P is started to pass, most of the components constituting the fixing device other than the fixing roller 11 are not heated and often remain at room temperature. For this reason, adhesion to peripheral members due to condensation of moisture and wax generated from the recording medium P and the toner image that have passed through the fixing nip 41 easily occurs.

  Further, the heating efficiency of the fixing roller 11 is increased by adopting an electromagnetic induction heating method as the heating method of the fixing roller 11. In this heating method, the magnetic flux generating member 161 needs to be installed close to the fixing roller 11. It is known that when moisture or wax is condensed on the magnetic flux generating member 161, an abnormal image is generated due to, for example, a droplet falling on the fixing roller 11. Therefore, the structure which prevents dew condensation is needed.

  The fixing roller 11 and the pressure roller 21 are arranged to face each other, and the nip forming member 32 presses the fixing roller 11 against the pressure roller 21, whereby a fixing nip 41 is formed between the fixing roller 11 and the pressure roller 21. The In order to prevent the nip forming member 32 from being deformed by a reaction force when the fixing roller 11 is pressed, a highly rigid pressure assisting member such as a metal material is supported so as to support the nip forming member 32 from the back side of the fixing nip 41. May be installed.

  The configuration of the fixing roller 11 is generally such that a base material layer, an elastic layer, and a surface layer are laminated in order from the inner peripheral side. However, in the present embodiment, an electromagnetic induction heating method is used as a heating unit for the fixing roller 11, so that a heating layer is formed between the base material layer and the elastic layer so that the fixing roller 11 can be easily heated. Further, when the performance requirement concerning the image quality is not high, there may be a two-layer structure including a base material layer and a surface layer except for the elastic layer.

  The base material layer is preferably a resin material such as polyimide or a metal material such as nickel or stainless steel having a thickness of 20 to 100 μm from the viewpoint of compatibility between flexibility and rigidity. Further, for the purpose of improving the slidability with the nip forming member 32 and the absorption rate of the radiant heat from the heating source, a coating material may be coated on the inner peripheral surface of the base material layer. For example, a fluorine resin coating is desirable for improving the slidability, and a black paint coating is desirable for improving the radiant heat absorption rate. The heating layer has a thickness of about 10 μm and is preferably a metal material, particularly copper. Heat is generated by mutual induction heating from the magnetic flux generating member 161. The elastic layer is preferably 50 to 300 [mu] m in thickness and uses an elastic material such as silicone rubber. Even if the surface of the recording medium P and the fixing roller 11 is uneven due to the deformation of the elastic layer, it is possible to improve the non-uniform pressure and thermal conductivity in the fixing nip 41 and improve the toner fixing quality. To do.

  The surface layer has a thickness of 3 to 50 μm, and a material having high releasability of the toner and the recording medium is used. For example, PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer), PTFE (tetrafluoroethylene resin), It is desirable to use polyimide, polyetherimide, PES (polyether sulfide) or the like.

  The nip forming member 32 is a fixed member, and the fixing roller 11 slides on the nip forming member 32. The material of the nip forming member 32 is preferably a highly heat-resistant resin material such as LCP (liquid crystal polymer), polyimide, PAI (polyamideimide). However, metal materials such as aluminum and stainless steel may be used. Although not shown, a material having a low friction coefficient can be wound around the nip forming member 32 as a sheet. Alternatively, the sliding frictional resistance of the fixing roller 11 with respect to the nip forming member 32 can be reduced by means such as coating the sliding surface with the fixing roller 11. The nip forming member 32 is fixedly supported on the frames 91 and 92 of the fixing device.

  The end flanges 101 and 102 are inscribed in the fixing roller 11 at the end of the fixing roller 11 in the rotation axis direction, and maintain the general shape of the fixing roller 11 that slides around. Further, the surface of the end flanges 101 and 102 that faces the side surface of the fixing roller 11 is fixed by contacting the side surface of the fixing roller 11 against the “belt shift” in which the fixing roller 11 moves in the direction of the rotation axis as the rotation rotates. The position of the roller 11 in the rotation axis direction is regulated.

  As in the embodiments described above, the present invention includes a first opening toward the nip exit space sandwiched between the first separation member and the second separation member, and the first opening toward the axial end surface of the fixing roller. The object is achieved by providing the intake member provided with the two openings. In other words, the air staying near the exit of the fixing nip and the end surface of the fixing roller is discharged through a predetermined path without newly providing a motor and a rotating shaft for generating an air flow in the fixing device separately from the fixing roller. The air flow to be able to be formed easily. This air flow suppresses the diffusion of floating substances such as moisture, wax generated from the recording medium and toner at the exit of the fixing nip, and chemical substances generated from the end face of the fixing roller into or around the fixing device. Can be easily collected and stored.

  Further, the first opening protrudes from the axial end surface of the fixing roller in the direction from the rotation shaft of the fixing roller to the nip exit space, so that the air flow is not blocked by the axial end surface of the fixing roller. The air staying in the nip outlet space can be reliably sucked. If the first opening protrudes only in the direction from the rotation axis of the fixing roller toward the nip outlet space, the intake efficiency for sucking the air staying in the nip outlet space can be increased.

  Of the air intake member, the openings that open toward the fixing nip are only the first opening and the second opening, and only the first opening is in the direction from the rotation axis of the fixing roller toward the nip exit space. In this configuration, the intake efficiency for sucking in the air remaining in the fixing roller axial end surface and the nip outlet space can be increased.

By adopting a configuration in which the second opening covers the end surface in the axial direction of the fixing roller, the flow rate of the air flow in the second opening necessary for collecting floating substances generated from the end surface of the fixing roller can be suppressed. . Therefore, the flow rate of the airflow in the first opening can be easily ensured.
If the first opening and the second opening are configured to be continuous, it is not necessary to form a complicated pipe shape, and the structure of the intake member can be simplified.
In addition, if the second opening is provided so as to face the axial end faces of both ends of the fixing roller as viewed from the fixing nip, suspended substances are generated from the fixing roller end on the side where the second opening is not provided. It can be prevented from spreading.
Furthermore, if an airflow generating member that generates an airflow from the nip exit space to the first opening and an airflow from the axial end surface of the fixing roller to the second opening is provided, air containing suspended solids is sucked in. An air flow passing through a predetermined path through the opening of the member can be generated.
If the fixing roller includes a fixing roller elastic resin layer formed of an elastic resin, and at least a part of the fixing roller elastic resin layer is exposed on the end surface in the axial direction, the elasticity of the fixing roller end surface is obtained. The chemical substances generated from the resin layer can be reliably recovered. If this fixing roller elastic resin layer is formed of a foamed elastic body, floating substances generated from the foam wall of the foamed elastic body and ejected from the end surface of the fixing roller can be reliably recovered.

  Further, if the temperature detection element that detects the temperature by receiving infrared light is opposed to the fixing rotator or the fixing roller and the operation of the fixing device is controlled based on the temperature detected by the temperature detection element, the infrared light receiving unit An error occurs in the detected temperature due to moisture or wax adhering to the surface. It is possible to suppress the amount of movement of air including water and wax near the fixing nip outlet toward the fixing rotator, and as a result, it is possible to suppress an error in the detected temperature of the temperature detecting element installed so as to face the fixing rotator.

  Further, the fixing rotating body or the fixing roller can be configured to be heated by an electromagnetic induction heating method installed on a magnetic flux generating member installed so as to face the outer peripheral surface. In the electromagnetic induction heating method, it is necessary to install the magnetic flux generating member close to the fixing rotator or the fixing roller. If moisture or wax condenses on the magnetic flux generating member, for example, a malfunction such as an abnormal image due to a drop of droplets falling on the fixing belt or the fixing roller occurs. Therefore, the configuration according to claim 1 prevents the condensation from occurring. Can be prevented.

  The present invention is not limited to the embodiments described above, and many variations are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

4: Photosensitive drum 9: Optical writing devices 9C to 9k: Toner bottle 11: Fixing roller 11a: Core metal part 11b: Elastic layer 11c: Temperature detection area 14: Paper discharge tray 20: Fixing device 21: Pressure roller 21a : Core metal part 21b: elastic layer 30: transfer belt 31: primary transfer roller 32: nip forming member 35: cleaning device 36: secondary transfer roller 41: fixing nip 71: suction member 71a: first opening 71b: Second opening 71c: Opening 71d: Hole 72: Intake member 81: Drive gear 91, 92: Frame 100: Image forming apparatus 101, 102: End flange 110: Feed roller 111: Frame 111c: Hole 112: Frame 120: Registration roller pair 121: Non-contact temperature sensor 121a: Light receiving unit 130: Sheet feeding device 131: For fixing Separating member 140: paper discharge roller 141: pressure separating member 151: airflow generating member 161: magnetic flux generating member 200: transfer belt unit 201: nip outlet space E: floating substance F: exhaust path G: gap H: floating substance P: Recording medium T: Recording medium conveyance direction W: Paper passing width

JP2013-015628A JP 2011-180235 A JP 2009-175663 A Japanese Patent Laid-Open No. 07-165365

Claims (13)

A fixing rotator,
A pressure rotator that presses against the fixing rotator and forms a fixing nip with the fixing rotator; and
A recording medium conveyed in the first conveyance direction of the recording medium in the fixing nip by rotating the pressure rotator in a first rotation direction of the rotation direction of the pressure rotator;
A first and second pair of separating members installed so as to face both the recording medium conveyed in the first conveying direction and carried out of the fixing nip and the outer peripheral surface of the fixing rotating body. When,
In the fixing device provided with
A first opening is provided toward a nip exit space of the fixing nip sandwiched between the first separation member and the second separation member, and a second opening is provided toward an axial end surface of the pressure rotator. Provided with an intake member having an opening of
A fixing device.   The said 1st opening part protrudes rather than the axial direction end surface of the said pressurization rotary body in the direction which goes to the said nip exit space from the rotating shaft of the said pressurization rotary body. The fixing device described.   The fixing device according to claim 2, wherein the first opening protrudes only in a direction from the rotation shaft of the pressure rotator toward the nip exit space. The opening of the intake member that opens toward the fixing nip side is only the first opening and the second opening.
4. The fixing device according to claim 2, wherein only the first opening protrudes in a direction from the rotation shaft of the pressure rotator toward the nip outlet space. 5.   5. The fixing device according to claim 1, wherein the second opening covers an axial end surface of the pressure rotator. 6.   The fixing device according to claim 1, wherein the first opening and the second opening are provided continuously.   7. The fixing device according to claim 1, further comprising the second opening so as to face axial end surfaces of both ends of the pressure rotator as viewed from the fixing nip.   An airflow generating member that generates an airflow from the nip exit space toward the first opening and an airflow from an axial end surface of the pressure rotator toward the second opening is provided. Item 8. The fixing device according to any one of Items 1 to 7. The pressure rotating body includes an elastic resin layer formed of an elastic resin,
9. The fixing device according to claim 1, wherein at least a part of the elastic resin layer is exposed on an end face in an axial direction of the pressure rotator.   The fixing device according to claim 9, wherein the elastic resin layer is made of a foamed elastic body.   A temperature detecting element for detecting temperature by receiving infrared light is arranged to face the fixing rotating body or the pressing rotating body, and the fixing operation is controlled based on the detected temperature of the temperature detecting element. The fixing device according to claim 1, wherein:   12. The heating device according to claim 1, wherein the fixing rotator or the pressure rotator is heated by an electromagnetic induction heating method installed on a magnetic flux generating member installed on an outer peripheral surface so as to face each other. Fixing device. An image forming apparatus comprising the fixing device according to claim 1.