JP2010204551A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively protect a detection environment where a temperature detecting means detects the temperature of an endless belt by reducing the amount of air reaching the temperature detecting means. <P>SOLUTION: This fixing device 27 includes a pressurizing belt 120, a plurality of steering roller 121 and separation roller 122 for suspending the pressurization belt 120, a non-contacting thermistor 300 for detecting the temperature of the pressurization belt 120, a cooling fan 500 for cooling the pressurization belt 120, and a roller steering means 53 that inclines the shaft of at least the steering roller 121, of a plurality of steering rollers 121 and separation rollers 122, with respect to the shaft of the separation rollers 122 and corrects the deviation of the pressurization belt 120. The fixing device 27 also includes a windbreak shutter 501 that is arranged between the cooling fan 500 and the non-contacting thermistor 300, is engaged with the shaft 121a of the steering roller 121, and suppresses the flow of the air coming from the cooling fan 500 to the non-contacting thermistor 300. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing device used in an electrophotographic image forming apparatus capable of forming an image on a recording material such as a multifunction machine, a copying machine, a printer, and a fax machine, and an image forming apparatus including the fixing device.

  An image forming apparatus such as an electrophotographic apparatus or an electrostatic recording apparatus forms a toner image on a recording material, and heats and presses the toner image to fix it. As a fixing device system used in such an image forming apparatus, a roller fixing system in which a fixing nip is formed by pressing a pressure roller against a fixing roller having a heater therein to perform fixing is conventionally employed.

  In recent years, the demand for improved printer productivity has been increasing. In order to further increase the gloss of the image and speed up the image formation, when the toner is softened and melted in the fixing process, it is required to efficiently give the toner a sufficient amount of heat to fix it on the recording material. It is done. Also, as the recording material increases in speed, the time for the recording material to pass through the nip decreases. Therefore, in order to efficiently apply heat to the recording material, the nip width (length in the recording material conveyance direction) is increased. There is a need. In the conventional roller pair fixing method, if the nip width is increased, the diameter of the roller increases, which leads to an increase in the size of the fixing device itself. Therefore, a fixing device described in Patent Document 1 is proposed that can obtain a sufficient nip width while corresponding to downsizing and speeding up of the device as compared with the roller fixing method.

  The fixing device described in Patent Document 1 is a belt heating type fixing device. According to this fixing device, it is possible to increase the width of the fixing nip by winding an endless belt around a part of the peripheral surface of the heating roll, and to apply heat and pressure to the recording material for a long time. be able to. Further, according to this fixing device, the endless belt is suspended on the plurality of rollers, and tension is applied to the endless belt, thereby ensuring a larger nip width. When tension is applied to the endless belt, the tension is applied to the endless belt by a tension roller that bridges the endless belt together with the pressure roller or the heating roller. In this case, the endless belt is displaced due to the deviation of the axial line between the pressure roller or heating roller and the tension roller.

  In addition, although not described in Patent Document 1, by correcting one side of the endless belt by changing the movement trajectory of the endless belt by intentionally shifting one of a plurality of rollers around which the endless belt is suspended. It is possible to do.

  Furthermore, although not described in Patent Document 1, in a situation where the temperature of the fixing member or the pressure member is higher than the desired temperature, a fixing member or the pressure member is applied by cooling air in a situation where the temperature of the fixing member or the pressure member is higher than a desired temperature. It is conceivable to cool.

Japanese Patent Laid-Open No. 10-319772

  However, when the endless belt is cooled by cooling air by tilting any of the shafts of the plurality of rollers to correct the deviation of the endless belt, the following problems may occur.

  The inside of the fixing device is maintained at an optimum temperature control temperature in order to fix the toner to the recording material. In order to maintain a desired temperature, the fixing device is provided with a temperature detecting means. By applying the cooling air for cooling the endless belt to the endless belt, the temperature detection sensor is also cooled, and there is a problem that the temperature of the surface of the endless belt cannot be detected correctly. This is particularly noticeable in a non-contact type temperature detection sensor. This is because the non-contact type temperature detection sensor measures the temperature of the object from the ambient temperature. That is, the cooling air for cooling the endless belt disturbs the ambient temperature in the vicinity of the endless belt, so that correct temperature detection cannot be performed.

  In addition, when a shutter member is provided to protect the temperature detection means from cooling air, the endless belt trajectory constantly changes due to the endless belt misalignment correction operation, so the clearance between the endless belt and the shutter member is set large. There must be. For this reason, the function of preventing cooling air is not sufficiently exhibited.

  Furthermore, if the arrangement of a plurality of rollers for suspending the endless belt is devised and the temperature detecting means is protected from the cooling air by the trajectory of the endless belt, the space surrounded by the endless belt increases and the apparatus itself becomes larger. There is a problem of end.

  In view of the above circumstances, the present invention reduces the amount of air reaching the temperature detection means without expanding the arrangement space of the endless belt, and effectively provides a detection environment in which the temperature detection means detects the temperature of the endless belt. It is an object of the present invention to provide a fixing device that can be protected.

  In order to solve the above-described problems, a fixing device according to the present invention includes an endless belt, a plurality of rollers that suspend the endless belt, and a temperature detection that faces the endless belt and detects the temperature of the endless belt. Means, a belt cooling means for flowing air toward the endless belt and cooling the endless belt, and at least one of the plurality of rollers is inclined with respect to the other rollers, and the endless belt is offset. And a roller tilting means for correcting the temperature of the belt, and the temperature detecting means is disposed between the belt cooling means and the temperature detecting means and is engaged with the shaft of the one roller. It has the 1st air flow suppression member which suppresses the flow of the air which goes to, It is characterized by the above-mentioned.

  As described above, according to the present invention, since the first air flow suppressing member is engaged with the shaft of one roller, when one roller is inclined with respect to the other roller by driving the roller steering means, Following this, the first air flow suppressing member is inclined. Therefore, since the endless belt and the first air flow suppressing member wound around one roller move integrally, the clearance between the first air flow suppressing member and the endless belt is kept constant. As a result, the amount of air reaching the temperature detection means is reduced, and the detection environment in which the temperature detection means detects the temperature of the endless belt is effectively protected.

1 is a cross-sectional view illustrating a configuration of an image forming apparatus including a fixing device according to an embodiment of the present invention. FIG. 3 is a cross-sectional view illustrating a part of the internal configuration of the fixing device. FIG. 3 is a side view showing a part of the internal configuration of the fixing device. It is the side view seen from the direction of the arrow P of FIG. FIG. 3 is a side view showing a part of the internal configuration of the fixing device. FIG. 4 is a side view showing a configuration in which a windproof shutter is arranged inside the fixing device. It is a perspective view which shows the engagement state of the hole of a wind-proof shutter, and the axis | shaft of a steering roller. FIG. 7 is a side view showing a state in which the clearance between the pressure belt and the windproof shutter is uniform and seen from the direction along the line DD in FIG. 6. FIG. 7 is a side view showing a state in which the clearance between the pressure belt and the windproof shutter is non-uniform, as viewed from the direction along line DD in FIG. 6. It is sectional drawing which shows the internal structure of the fixing device which engaged the wind-proof shutter with the steering roller. FIG. 11 is a side view showing the state when the shaft of the steering roller is arranged in parallel to the shaft of the separation roller, as viewed from the direction of the arrow Q in FIG. 10. FIG. 11 is a side view showing a state where the shaft of the steering roller is arranged to be inclined with respect to the shaft of the separation roller, as viewed from the direction of the arrow Q in FIG. 10. FIG. 11 is a side view showing a state of clearance between the pressure belt and the windproof shutter when the pressure belt is inclined with respect to the axis of the separation roller, as viewed from the direction along line DD in FIG. 10. FIG. 6 is a side view showing an internal configuration of a fixing device according to another embodiment of the present invention.

  Hereinafter, exemplary embodiments of the present invention will be described in detail by way of example. However, since the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are appropriately changed depending on the configuration of the apparatus to which the present invention is applied and various conditions, there are particularly specific descriptions. As long as there is not, it is not the meaning which limits the scope of the present invention only to them.

  FIG. 1 is a cross-sectional view illustrating a configuration of an image forming apparatus 100 including a fixing device 27 according to an embodiment of the present invention. As shown in FIG. 1, the image forming apparatus 100 includes an image forming apparatus main body (hereinafter simply referred to as “apparatus main body”) 100A. The image forming apparatus 100 is a copier, a printer, a facsimile machine, a multifunction machine, or the like. In addition, a fixing device 27 is provided inside the apparatus main body 100A for applying a heat and pressure to the unfixed image transferred on the recording material S to perform a permanent fixing process. However, although a full color intermediate transfer system is shown as a specific example of the image forming apparatus 100, it is not particularly limited thereto.

  Inside the apparatus main body 100A, for example, an “image carrier” that carries an electrostatic latent image on the surface corresponding to four color toner images of Y (yellow), M (magenta), C (cyan), and K (black). ] Photosensitive drums 20Y, 20M, 20C, and 20K. Hereinafter, in order to avoid complication of the description, the four image carriers are denoted by reference numeral 20, and the following primary charging devices 21Y to 21K, exposure devices 22Y to 22K, and developing devices 23Y to 23K are also described. Similarly, 21, 22, and 23 are used as representative codes. The following primary transfer devices 24Y to 24K, image forming units 200Y to 200K, and the like are also described by using 24 and 200 as the representative symbols.

  The surfaces of the four photosensitive drums 20 are uniformly charged to a required potential by the primary charging device 21, and then the surfaces of the photosensitive drums 20 are exposed to light by exposing the surfaces of the photosensitive drums 20 by the exposure device 22. An electrostatic latent image is formed. Then, the electrostatic latent image on the surface of the photosensitive drum 20 is developed using a developer by the developing device 23 and is visualized as a toner image.

  In the apparatus main body 100A, image forming units 200Y, 200M, 200C, and 200K corresponding to the above-described four-color toner image formation are arranged in series, and a tandem that performs parallel processing for each color until a visible image is formed. The method is adopted.

  The toner image on the photosensitive drum 20 developed by the developing device 23 is subjected to primary transfer by being sequentially superimposed on an intermediate transfer member 25 by an endless belt, for example, by a primary transfer device 24. Then, the toner image on the intermediate transfer body 25 that has been primary-transferred for all colors is collectively transferred onto the recording material S by the secondary transfer device 26. The recording material S is conveyed to the secondary transfer device 26 by a paper feeding unit. After the secondary transfer, the recording material S carrying an unfixed toner image is conveyed to the belt-type fixing device 27 according to the present embodiment, and heated and pressed by the fixing device 27, whereby an unfixed toner image is formed. After being fixed by melting and softening, it is discharged to the discharge tray 28 after fixing. When an image is formed on the back side, the recording material is reversed by the recording material reversing path 29 and then conveyed again to the secondary transfer device 26 via the duplex conveying path 30 to form an image on the back side. .

  As described above, a series of image forming processes from charging, exposure, development, transfer, and fixing are executed, and an image is recorded and formed on the recording material S. In a monochrome image forming apparatus, only a black image forming unit exists. The order and configuration of the Y, M, C, and K image forming units 200 are not limited to this.

  FIG. 2 is a cross-sectional view showing a part of the internal configuration of the fixing device 27. As shown in FIG. 2, the fixing device 27 that is an “image heating device” includes a fixing roller 10 as a “heating rotator (fixing rotator)”. The fixing roller 10 is provided so as to be rotatable in the direction of arrow A by a drive motor or a drive gear train (not shown) as “drive means”.

  The fixing roller 10 includes a cored bar 111 made of metal such as aluminum and an elastic layer 112 made of silicone rubber or the like on the surface layer thereof. A halogen heater 113 as a “heating source” is disposed inside the fixing roller 10, and the fixing roller 10 is heated by heat from the halogen heater 113.

  A thermistor 114 as a “temperature detection element” is disposed in contact with the surface of the fixing roller 10. The control device 51 maintains the surface of the fixing roller 10 at a predetermined fixing temperature by controlling the energization amount to the halogen heater 113 according to the detection result by the thermistor 114.

  A belt unit 2 is disposed below the fixing roller 10. The pressure belt 120 which is an “endless belt” is formed in an endless shape and is stretched by a steering roller 121 and a separation roller 122.

  The separation roller 122 is made of a metal such as SUS, and is pressed against the fixing roller 10 with a predetermined pressure via the pressure belt 120 in the direction of arrow B.

  Only one end of the rotation shaft of the steering roller 121 is movable in the direction of arrow C, and the displacement of the pressure belt 120 is controlled by shifting the parallelism between the separation roller 122 and the steering roller 121.

  The longitudinal position of the pressure belt 120 is detected by belt position detection sensors 400 provided at both ends. The belt offset correction operation will be described later.

  A pressure pad portion 124 for forming a fixing nip is disposed between the steering roller 121 and the separation roller 122. The pressure pad portion 124 includes a pressure base 125 made of a metal such as SUS and a pressure pad 126 made of silicone rubber or the like. The surface of the pressure pad 126 is covered with a low sliding sheet 127 made of a PI film or the like in order to reduce sliding resistance with the pressure belt 120. The pressure pad portion 124 configured in this manner is pressurized in the direction of arrow B in the same manner as the separation roller 122.

  A halogen heater 128 is disposed inside the separation roller 122 as a heat source, and the entire pressure belt 120 is heated via the separation roller 122. Below the pressure belt 120, a non-contact thermistor 300 that is “temperature detection means” is arranged. The non-contact thermistor 300 monitors the temperature of the central portion in the longitudinal direction of the pressure belt 120. If a contact type thermistor is brought into contact with the sheet passing area of the pressure belt 120, the thermistor and the pressure belt 120 are rubbed and damage the surface of the pressure belt 120. A non-contact thermistor 300 is used.

  Since the toner image on the recording material S is melted and pressed at the nip W of the fixing device 27, the toner and the surface layer of the fixing roller 10 tend to stick to each other. However, since the elastic layer 112 of the fixing roller 10 is greatly elastically deformed by the separation roller 122, the toner stuck to the fixing roller 10 is peeled off and the recording material S is discharged in the direction of arrow Y.

  In such a pressure belt 120, a long nip W is formed by the fixing roller 10, the pressure belt 120, the pressure pad portion 124, and the separation roller 122. As a result, the nip width can be made wider than that of a conventional roller fixing device using a fixing roller and a pressure roller, so that the toner on the recording material S can be melted well in a short time. Therefore, this configuration is suitable for an image forming apparatus that uses a large amount of toner such as a color image forming apparatus.

  FIG. 3 is a side view showing a part of the internal configuration of the fixing device 27. With reference to FIG. 3, the configuration of the roller steering means 53, which is a “roller tilting means”, will be described. Further, endless belt deviation correction by roller steering operation will be described. As shown in FIG. 3, in the roller steering means 53, the tension spring 401 applies tension to the pressure belt 120 via a bearing 402 engaged with the shaft 121a of the steering roller 121 (see FIG. 2). Yes. The tension of the pressure belt 120 is, for example, 50N. By applying tension to the pressure belt 120, the pressure belt 120 is wound around the steering roller 121, which is a tension roller, so that the pressure belt 120 can be shifted by a roller steering operation.

  A tensioner 403 is further engaged with the bearing 402 on the outside. Gear teeth 404 are formed at one end of the tensioner 403.

  When the worm gear 405 engaged with the gear teeth 404 is rotated by the motor M, the tensioner 403 rotates about the rotation shaft 406. By this operation, the steering roller 121 moves in either the up or down direction of the arrow C in FIGS.

  Now, when the steering roller 121 moves in the direction of FIG. C, the parallelism with the separation roller 122 is lost, and the pressure belt 120 is offset.

  4 is a side view seen from the direction of arrow P in FIG. As shown in FIG. 4, the belt position detection sensor 400 includes a left side belt position detection sensor 400a and a right side belt position detection sensor 400b. In the state of FIG. 4, when the pressure belt 120 approaches the left side (“front” in FIG. 4, the same applies hereinafter), the belt position detection sensor 400 a detects the displacement of the pressure belt 120. Then, the CPU 52 operates the motor M so as to move the back side of the steering roller 121 to the upper side of the arrow C in FIG. By this operation, the pressure belt 120 is shifted to the right ("back" in FIG. 4, the same applies hereinafter).

  When the pressure belt 120 approaches the right side ("back" in FIG. 4, the same applies hereinafter), the belt position detection sensor 400b detects the displacement of the pressure belt 120. Then, the CPU 52 operates the motor M so as to move the inner side of the steering roller 121 to the lower side of the arrow C in FIG. By this operation, the pressure belt 120 is shifted to the left. By repeating the above operation, the pressure belt 120 rotates while reciprocating within a predetermined range.

  As shown in FIG. 4, the temperature of the pressure belt 120 is detected by a non-contact thermistor 300. The CPU 52 determines whether or not the pressure belt 120 has reached a predetermined temperature, and the temperature control temperature is maintained by appropriately controlling the energization amount of the halogen heater 128.

  FIG. 5 is a side view showing a part of the internal configuration of the fixing device 27. Although the energization amount of the halogen heater 128 is adjusted appropriately, the recording material S having various sizes, basis weights, and image densities passes through the fixing device 27 while the recording material S is passing therethrough. Therefore, it is difficult to always maintain the temperature at a desired temperature. Furthermore, the optimum temperature adjustment temperature varies depending on the basis weight of the recording material S. Therefore, the temperature of the pressure belt 120 may be higher than a desired temperature. In order to lower the temperature of the pressure belt 120 in a short time, as shown in FIG. 5, a cooling fan 500 as a “belt cooling unit” is provided to face the pressure belt 120. When the cooling air from the cooling fan 500 is applied to the pressure belt 120, the temperature of the pressure belt 120 is lowered. However, as shown in FIG. 5, simply cooling the temperature of the pressure belt 120 with the cooling fan 500 disturbs the temperature atmosphere of the non-contact thermistor 300 and makes it impossible to detect the correct temperature.

  FIG. 6 is a side view showing a configuration in which a windproof shutter 501 is arranged inside the fixing device 27. As shown in FIG. 6, a case is considered in which only a windproof shutter 501 is provided between a cooling fan 500 that is “cooling means” and a non-contact thermistor 300 that is “temperature detection means”.

  FIG. 7 is a perspective view showing an engagement state of the hole 501a of the windproof shutter 501 and the shaft 121a of the steering roller 121. As shown in FIG. As shown in FIG. 7, the windproof shutter 501 has an L-shaped cross section. The windproof shutter 501 has bent portions 501P at both ends, and a hole 501a is formed in the bent portion 501P. Further, in FIG. 7, the steering roller 121 drawn by a two-dot chain line has a shaft 121a. The hole 501 a of the windproof shutter 501 is engaged with the shaft 121 a of the steering roller 121. With such a configuration, when the steering roller 121 is tilted, the windproof shutter 501 is tilted following the tilt.

  FIG. 8 shows a state in which the clearance between the pressure belt 120 and the windproof shutter 501 is uniform, and is a side view seen from the direction along the line DD in FIG. As shown in FIG. 8, when the parallelism of the steering roller 121 and the separation roller 122 is maintained without performing the deviation correction operation, the clearance between the pressure belt 120 and the windproof shutter 501 is constant. It is kept. Note that the pressure belt 120 is illustrated in FIG. 8 as a cross section 120a of the pressure belt 120 on a plane along the line DD in FIG.

  FIG. 9 is a side view showing a state in which the clearance between the pressure belt 120 and the windproof shutter 701 is non-uniform, as seen from the direction along the line DD in FIG. As shown in FIG. 9, when the steering roller 121 performs the deviation correction operation of the pressure belt 120, the pressure belt 120 is twisted. The cross section 120 a of the pressure belt 120 is inclined with respect to the shaft 122 a of the separation roller 122.

  At this time, if the windproof shutter 701 is not engaged with the shaft 121a of the steering roller 121, the clearance between the windproof shutter 701 and the pressure belt 120 is separated as shown in FIG. It is not uniform in the axial direction. For this reason, uneven cooling in the longitudinal direction of the steering roller 121 occurs, or the temperature of the non-contact thermistor 300 is not normally detected. From this, it is important that the windproof shutter 501 is hooked on the shaft 121a of the steering roller 121 as shown in FIG. The windproof shutter 501 may be supported by the shaft 121a so that the posture is maintained even if the shaft 121a rotates.

  FIG. 10 is a cross-sectional view showing an internal configuration of the fixing device 27 in which a windproof shutter 501 that is a “first air flow suppressing member” is engaged with the steering roller 121. As shown in FIG. 10, the fixing device 27 includes a pressure belt 120 and a plurality of steering rollers 121 and separation rollers 122 that suspend the pressure belt 120. In addition, the fixing device 27 is disposed to face the pressure belt 120, detects the temperature of the pressure belt 120, and causes the air to flow toward the pressure belt 120. A cooling fan 500 is provided for cooling. Further, the fixing device 27 is a roller steering unit that corrects a deviation of the pressure belt 120 by inclining at least the shaft 121a of the steering roller 121 of the plurality of steering rollers 121 and the separation roller 122 with respect to the shaft 122a of the separation roller 122. 53. The roller steering means 53 is described in FIG.

  Further, the fixing device 27 includes a windproof shutter 501. The windproof shutter 501 is disposed between the cooling fan 500 and the non-contact thermistor 300 and is engaged with the shaft 121a of the steering roller 121 to suppress the flow of air from the cooling fan 500 toward the non-contact thermistor 300. The hole 501a of the windproof shutter 501 is engaged with the shaft 121a of the steering roller 121.

  Further, the fixing device 27 includes a barrier 131 that extends from the wall surface 27B of the fixing device main body 27A toward the steering roller 121 and suppresses the flow of air from the cooling fan 500 toward the non-contact thermistor 300. That is, the wall 130 </ b> B of the wall 130 that is a part of the fixing device main body 27 </ b> A extends upward from the barrier 131 that is the “second air flow suppressing member”. The windproof shutter 501 and the barrier 131 are provided so as to overlap each other when viewed from the cooling fan 500. A part of the fixing device main body 27A is the wall 130, and a part of the wall surface 27B is the wall surface 130B.

  FIG. 11 is a side view showing the state when the shaft 121a of the steering roller 121 is arranged in parallel to the shaft 122a of the separation roller 122, as viewed from the direction of the arrow Q in FIG. As shown in FIG. 11, when the parallelism of the steering roller 121 and the separation roller 122 is maintained without performing the deviation correction operation, the clearance between the pressure belt 120 and the windproof shutter 501 is constant. It is kept.

  FIG. 12 is a side view showing the state when the shaft 121a of the steering roller 121 is arranged to be inclined with respect to the shaft 122a of the separation roller 122, as viewed from the direction of the arrow Q in FIG. As shown in FIG. 12, when the steering roller 121 performs the deviation correction operation of the pressure belt 120, the pressure belt 120 is twisted and the surface of the pressure belt 120 is in the axial direction of the steering roller 121 (see FIG. 12). 12 in the horizontal direction).

  That is, as the steering roller 121 and the pressure belt 120 are inclined with respect to the shaft 122a of the separation roller 122, the windproof shutter 501 engaged with the shaft 121a of the steering roller 121 is inclined. For this reason, the clearance between the windproof shutter 501 and the pressure belt 120 is always kept uniform in the axial direction of the steering roller 121. Therefore, uneven cooling in the longitudinal direction of the steering roller 121 is suppressed, and the temperature of the non-contact thermistor 300 is normally detected.

  Here, it returns and demonstrates to FIG. The fixing device 27 has a fixing device main body 27A, and a barrier wall 131 is formed on the wall surface 27B of the floor side wall 130 which is a part of the fixing device main body 27A. This is provided for the following reason.

  That is, when the windproof shutter 501 tilts following the deviation correction operation of the steering roller 121, a space is generated between the lower end of the windproof shutter 501 and the barrier 131. In order to prevent the air flowing from the cooling fan 500 from passing through the above-described space, the above-described barrier 131 is disposed between the windproof shutter 501 and the cooling fan 500.

  FIG. 13 shows a state of clearance between the pressure belt 120 and the windproof shutter 501 when the pressure belt 120 is inclined with respect to the shaft 122a of the separation roller 122, and is taken along the line DD in FIG. It is the side view seen from the direction. In FIG. 13, since the barrier 131 is not visible from the DD plane, the projection line 131a of the barrier 131 is shown by a broken line. FIG. 12 shows a state seen from the cooling fan 500, and only the clearance between the pressure belt 120 and the windproof shutter 501 remains at the upper end of the windproof shutter 501. Even if the air is going from the cooling fan 500 to the non-contact thermistor 300, the passage is first blocked by the barrier 131 and then blocked by the wind-proof shutter 501. For this reason, most of the air cannot reach the non-contact thermistor 300. As a result, the temperature detection accuracy of the non-contact thermistor 300 is stabilized regardless of whether the steering operation of the steering roller 121 is performed. By such an action, it is possible to correctly detect the temperature of the pressure belt 120 by effectively operating the non-contact thermistor 300 while effectively cooling the pressure belt 120.

  In this embodiment, the fixing device is shown in which the pressure unit is a belt winding system, but the present invention is not limited to this, and the fixing unit and the pressure unit are both belt winding systems. It can also be implemented in the apparatus.

  FIG. 14 is a side view showing an internal configuration of a fixing device 57 according to another embodiment of the present invention. FIG. 14 shows a state in which the windproof shutter 801 is engaged with the shaft 121 a of the steering roller 121. In the above-described embodiment, the windproof shutter 501 is configured as a single item, but is not limited to the above embodiment. That is, it is possible to configure with two members like the windproof shutter 801. The windproof shutter 801 includes a shutter part 801a and an L-shaped part 801b. The strength of the windproof shutter 501 is increased by providing the L-shaped portion 801b on the surface of the shutter portion 801a formed on the cooling fan 500 side.

  As described above, according to the embodiments of the present invention and other embodiments, the following effects can be obtained. That is, when the shaft 121a of the steering roller 121 is tilted with respect to the shaft 122a of the separation roller 122 by driving the roller steering means 53, the shaft 121a of the steering roller 121 and the windproof shutter 501 are integrally tilted. Therefore, the clearance between the windproof shutter 501 and the pressure belt 120 is kept constant. As a result, the amount of air reaching the non-contact thermistor 300 is reduced, and the detection environment in which the non-contact thermistor 300 detects the temperature of the pressure belt 120 is effectively protected.

  Further, according to the embodiment of the present invention and other embodiments, the fixing device 27 extends from the wall surface 27B of the fixing device main body 27A toward the steering roller 121, and the air flowing from the cooling fan 500 toward the non-contact thermistor 300. The barrier 131 is provided to suppress the flow of. Further, the windproof shutter 501 and the barrier 131 are provided so as to overlap each other when viewed from the air flow direction. As a result, the entry of air between the windproof shutter 501 and the pressure belt 120 is suppressed by the operation of the windproof shutter 501. In contrast, the entry of air between the windproof shutter 501 and the wall 130 of the fixing device 27 body is suppressed by the barrier 131.

27 fixing device 27A fixing device body 27B wall surface 53 roller steering means 120 pressure belt 121 steering roller 122 separation roller 131 wall (second air flow suppressing member)
200Y to 200K ... Image forming unit 300 Non-contact thermistor (temperature detection means)
500 Cooling fan (cooling means)
501 Windproof shutter (first air flow suppressing member)

Claims (3)

An endless belt, a plurality of rollers for suspending the endless belt, a temperature detecting means that is disposed to face the endless belt, detects the temperature of the endless belt, and flows air toward the endless belt, In a fixing device, comprising: belt cooling means for cooling an endless belt; and roller inclination means for inclining at least one of the plurality of rollers with respect to other rollers to correct a deviation of the endless belt.
A first air flow suppression disposed between the belt cooling unit and the temperature detection unit and engaged with the shaft of the one roller to suppress air flow from the belt cooling unit to the temperature detection unit. A fixing device comprising a member.   A second air flow suppressing member that extends from the wall surface of the fixing device main body toward the one roller and suppresses the flow of air from the belt cooling unit to the temperature detecting unit; The fixing device according to claim 1, wherein the second air flow suppression member is provided so as to overlap when viewed from the cooling unit. An image forming unit for forming an image on a recording material;
A fixing device according to claim 1 or 2,
An image forming apparatus comprising:

Images