JP2011028081A - Image heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the flip-flopping phenomenon of the rotational trajectory of a sleeve when a tensionless type image heating device 10 adopting a film heating system is started up. <P>SOLUTION: The image heating device includes a separation member 29 which is disposed to face the sleeve on the downstream side from a nip potion N in the conveying direction D of a recording material and is for performing separation so that the recording material exiting from the nip part N is not wound on the sleeve 23 and a rotatable roller 28 which is for regulating the rotational trajectory of the sleeve. The part facing the sleeve of the roller is located on the upstream side from the part facing the sleeve of the separation member in the conveying direction of the recording material. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a film heating system and a tensionless type image heating apparatus. As an image heating device, a fixing device for fixing or hypothetically fixing an unfixed image formed on a recording material, or for increasing the glossiness of an image by reheating the image fixed on the recording material, etc. Examples thereof include an image modifying apparatus.

  The applicant previously applied a tensionless type with a film heating method that is effective as a fixing device mounted on an image forming apparatus such as a copying machine, a printer, or a facsimile machine using electrophotographic technology or electrostatic recording technology. Proposed image heating apparatus (Patent Documents 1 to 3). This device is an on-demand device that has high heat transfer efficiency and quick start-up from the viewpoint of promoting energy saving. The basic structure is a fixedly supported heating body, a flexible sleeve that can rotate while the heating body and the inner surface slide, and a nip portion formed by pressure contact with the heating body via the sleeve. And a driving means for rotating the pressure roller. The sleeve is driven to rotate loosely by rotating the pressure roller, the recording material carrying the image is sandwiched and conveyed between the sleeve in the nip and the pressure roller, and the image is generated by the heat from the heating body via the sleeve. It is the structure which heats. At least a part of the circumference of the sleeve having flexibility is always tension-free, that is, no tension is applied to the sleeve, and the sleeve is rotated by the rotational driving force of the pressure roller. As the heating body, for example, a ceramic heater that rapidly rises in temperature when energized is used. As the flexible sleeve, for example, a thin cylindrical heat resistant resin film having a small heat capacity and good thermal response is used, and the thermal response of the heating body can be reflected almost directly in the nip portion. Accordingly, the fixing temperature is reached in a shorter time than when the heater is energized-on (on-demand system), and power saving associated therewith is realized. Further, the tensionless type device has a small shift force along the length of the sleeve support member when the sleeve is in a rotationally driven state, and can simplify the shift control means or the shift control means of the sleeve. For example, the sleeve shift movement restricting means can be as simple as a flange member for receiving the end of the sleeve, and the sleeve shift control means can be omitted to reduce the cost and size of the apparatus.

JP-A-4-44075 JP-A-4-204980 JP 2005-63730 A

  The present invention is a further development of a tensionless type image heating apparatus using the film heating method as described above. SUMMARY OF THE INVENTION An object of the present invention is to provide an image heating apparatus in which the rotation trajectory of the sleeve at the time of starting up the apparatus can suppress the flutter phenomenon. Another object of the present invention is to provide an image heating apparatus capable of reducing the rotational unevenness of the sleeve and narrowing the gap between the sleeve and the recording material separating member to improve the recording material separating performance. Another object of the present invention is to provide an image heating apparatus capable of shortening the rise time to the target temperature.

  In order to achieve the above object, a typical configuration of an image heating apparatus according to the present invention includes a heating body, a flexible sleeve that can rotate while an inner surface slides relative to the heating body, A pressure roller that presses against the heating body via a sleeve to form a nip portion; and a driving means that rotates the pressure roller. The sleeve is loosened by rotating the pressure roller. An image heating apparatus that rotates following, sandwiches and conveys a recording material carrying an image between the sleeve and the pressure roller of the nip portion, and heats the image by heat from the heating body via the sleeve. In order to separate the recording material from the nip portion, which is disposed on the downstream side of the nip portion in the recording material conveyance direction so as to face the sleeve, so that the recording material does not wind around the sleeve. And a roller that can rotate to regulate the rotation trajectory of the sleeve, and a portion of the roller facing the sleeve is located upstream of the separation member facing the sleeve in the recording material conveyance direction. It is located.

  To achieve the above object, another representative configuration of the image heating apparatus according to the present invention includes a heating body, and a flexible sleeve that can rotate while an inner surface slides relative to the heating body. A pressure roller that presses against the heating body via the sleeve to form a nip portion, and a driving means that rotates the pressure roller, and the sleeve is rotated by rotating the pressure roller. Image heating in which the recording material carrying the image is nipped and conveyed between the sleeve of the nip and the pressure roller, and the image is heated by the heat from the heating body via the sleeve. An apparatus for separating a recording material from the nip portion, which is disposed opposite to the sleeve at a downstream side of the nip portion in the recording material conveyance direction so as not to wind around the sleeve. A separation member, and a rotatable roller for regulating a rotation trajectory of the sleeve, wherein a portion of the roller facing the sleeve is upstream of a portion of the separation member facing the sleeve in the recording material conveyance direction The roller is moved to a first position where the roller comes into contact with the sleeve and restricts the rotation trajectory of the sleeve, and a second position where the roller comes into a non-contact state with the sleeve. To do.

  Still another representative configuration of the image heating apparatus according to the present invention for achieving the above object includes a heating body and a flexible sleeve that can rotate while an inner surface slides relative to the heating body. And a pressure roller that forms a nip portion in pressure contact with the heating body via the sleeve, and a drive unit that rotates the pressure roller, and the sleeve is rotated by rotating the pressure roller. An image that heats the image by heat from the heating body via the sleeve by nipping and conveying the recording material carrying the image between the sleeve of the nip and the pressure roller. A heating device for separating the recording material, which is disposed opposite to the sleeve at the downstream side in the recording material conveyance direction from the nip portion so as not to wind around the sleeve. Minutes A member and a trajectory correction guide disposed inside the sleeve for regulating the rotation trajectory of the sleeve, wherein the trajectory correction guide regulates the rotation trajectory of the sleeve in contact with the inner surface of the sleeve And a guide position for moving the guide member to a position where the guide member is brought into a non-contact state with respect to the inner surface of the sleeve by receiving heat from the sleeve through the guide member and being heated. And an adjusting member.

  According to the present invention, it is possible to provide an image heating apparatus in which the rotation trajectory of the sleeve at the start-up of the apparatus can suppress the flutter phenomenon. In addition, according to the present invention, it is possible to provide an image heating apparatus capable of reducing the rotation unevenness of the sleeve and narrowing the gap between the sleeve and the recording material separating member to improve the recording material separating performance. In addition, according to the present invention, it is possible to provide an image heating apparatus capable of shortening the rise time to the target temperature.

(A) is a schematic cross-sectional view of the main part of the fixing device in the first embodiment, and (b) is a front schematic view (recording material inlet side) of the main part of the fixing device omitted. FIG. 4A is a schematic rear view (recording material outlet side) of the main part of the fixing device omitted in the middle, and FIG. 4B is a perspective view of the main part on one end side of the fixing device. (A) is an enlarged schematic view of a roller and a separating member, (b) is an explanatory view of a rotating trajectory of a film when there is no roller, and (c) is an explanatory view of a rotating trajectory of the film when there is a roller. . (A) is a diagram showing the rotation trajectory of the film in the vicinity of the separating member, and (b) is a time-series recording of fluctuations in the gap between the leading end of the separating member and the film when the fixing device is started up without providing a roller. FIG. 8C is a diagram in which fluctuations in the gap between the leading end of the separating member and the film when the fixing device provided with the rollers is started are recorded in time series. (A) is a cross-sectional schematic diagram of the principal part of the fixing device in the second embodiment, (b) is a schematic diagram when the roller is moved to the first position, and (c) is the second roller. It is a schematic diagram at the time of the state which has moved to position. (A) is an operation | movement flowchart of a roller, (b) is explanatory drawing of arrangement | positioning of the roller in 1st embodiment, (c) is explanatory drawing of arrangement | positioning of the roller in 2nd embodiment. (A) is the figure which showed the gap of the roller and film in 1st embodiment, (b) is the figure which showed the gap of the roller and film in 2nd embodiment. (A) is a cross-sectional schematic diagram of the principal part of the fixing device in 3rd embodiment, (b) is an enlarged schematic diagram of a track | orbit correction guide part. (A) is a diagram showing the movement of the trajectory correction guide before and after the fixing process, and (b) is an operation flowchart of the trajectory correction guide. It is explanatory drawing of a structure and operation | movement of a track correction guide. (A) is the graph which showed the fixing film temperature change when the track | orbit correction guide contact | abuts and leaves | separates, (b) is a cross-sectional schematic diagram of the principal part of the fixing device in 4th Embodiment. It is explanatory drawing of a structure and operation | movement of a track correction guide. (A) is an operation | movement flowchart of a track | orbit correction guide, (b) is the schematic of the temperature characteristic of the spring constant of the spring member which consists of shape memory alloys. (A) is a structural model figure of an example of an image forming apparatus, (b) is a partial enlarged view.

  Hereinafter, the present invention will be described more specifically with reference to examples. Although these examples are examples of embodiments to which the present invention can be applied, the present invention is not limited to these examples, and various modifications are possible within the scope of the idea of the present invention.

[First embodiment]
(1) Example of Image Forming Apparatus FIG. 14A is a structural model diagram of an example of an image forming apparatus in which the image heating apparatus according to the present invention is mounted as the heat fixing apparatus 10. (B) is an enlarged view of the image forming stations Pm, Pc, Py, Pbk and the recording material transport belt 7 of the image forming apparatus of (a). This image forming apparatus is an electrophotographic full-color copying machine. Four image forming stations Pm, Pc, Py, and Pbk are disposed in the center of the apparatus along the conveyance direction of the recording material P that is conveyed on the upper surface of the belt 7. Pm is an image forming station for magenta, Pc is an image forming station for cyan, Py is an image forming station for yellow, and Pbk is an image forming station for black. Each image forming station includes a drum-type electrophotographic photosensitive member (hereinafter referred to as a drum) 1 as an image carrier, a charging device 2, a developing device 4, and a cleaner 5. An exposure device 3 that exposes an image to the drum 1 of each image forming station is provided. On the upper surface side of the image forming apparatus, a reader unit R that photoelectrically reads an image of a document placed on a document table is provided. A feeding tray T on which the recording material P is stacked and stored is provided below the inside of the apparatus. C is a large-capacity feeding unit capable of stacking and storing a large amount of recording material P of a predetermined size. H is a manual feed tray capable of feeding a desired recording material P.

  The full color image forming operation is as follows. In response to the copy job, first, the drum 1 of the image forming station Pm is rotated in a predetermined direction, and the outer peripheral surface (surface) of the drum 1 is uniformly charged to a predetermined potential and polarity by the charging device 2. The exposure device 3 performs image exposure with the laser beam L modulated in accordance with the image data output from the reader unit R on the charged surface of the drum 1. As a result, an electrostatic latent image corresponding to the image data is formed on the surface of the drum 1. The latent image is developed by the developing device 4 using magenta toner. The charging, exposure, and development processes as described above are sequentially performed at the image forming stations Pc, Py, and Pbk. On the other hand, at a predetermined control timing, the recording material P is fed from the feeding tray T, the large-capacity feeding unit C, or the manual feed tray H, and is fed to the upper surface of the belt 7 moving around in the direction of the arrow. It is fed by the feeding mechanism 6. The belt 7 is wound around a driving roller 8a and a tension roller 8b, and the upper surface of the ascending belt portion faces the drum 1 of each image forming station Pm, Pc, Py, Pbk. The belt 7 is driven to move around in the direction of the arrow according to the copy job. By the circular movement of the belt 7, the recording material P is conveyed between the drum 1 of the image forming station Pm and the transfer device 9 arranged so as to oppose the drum 1 via the conveying belt 7. Then, the magenta toner image on the surface of the drum 1 is transferred onto the recording material P by the transfer device 9. The transfer process as described above is sequentially performed at the image forming stations Pc, Py, and Pbk. In this manner, the recording material P sequentially receives superimposed transfer of toner images of four colors, magenta, cyan, yellow, and black, to form an unfixed full-color toner image. The recording material P is separated in curvature from the upper surface of the belt 7 at the position of the driving roller 8 a by the subsequent circular movement of the belt 7. Then, it is relayed to the conveying device B, introduced into a heat fixing device (hereinafter referred to as a fixing device) 10, and nipped and conveyed by a nip portion (fixing nip portion) N of the fixing device 10. During the conveyance process, heat and pressure are applied to the recording material P, and an unfixed toner image is heated and fixed on the recording material P. The recording material P exiting the fixing device 10 is discharged onto the tray 12 by the roller 11. The full-color copying machine of the present embodiment is configured to convey recording materials P of various sizes that can be used with reference to the center in the width direction of the recording material (central conveyance reference). Here, regarding the recording material, the width direction is a direction orthogonal to the recording material conveyance direction on the surface of the recording material.

(2) Fixing device 10
(2-1) Overall Schematic Configuration of Fixing Device 10 FIG. 1A is a schematic cross-sectional view of the main part of the fixing device 10, and FIG. (Recording material inlet side). FIG. 2A is a schematic rear view (recording material outlet side) of a middle portion of the main portion of the fixing device 10 omitted, and FIG. 2B is a perspective view of the main portion on one end side of the fixing device 10. The fixing device 10 is a film heating type and tensionless type image heating device. The apparatus 10 includes a heating body 21, a flexible sleeve 23 that can rotate while the heating body 21 and the inner surface slide, and a heating section 21 that presses against the heating body 21 to form a nip portion N. A pressure roller 25 and driving means M for rotating the pressure roller 25 are provided. Then, by rotating the pressure roller 25, the sleeve 23 is driven to rotate loosely, and the recording material P carrying the image t is sandwiched and conveyed between the sleeve 23 of the nip portion N and the pressure roller 25, and the sleeve 23. The image t is heated by the heat from the heating body 21 via the. At least a part of the circumference of the sleeve 23 having flexibility is always tension-free, that is, no tension is applied to the sleeve, and the sleeve 23 is rotated by the rotational driving force of the pressure roller 25.

  In the fixing device 10 of the present embodiment, a ceramic heater (hereinafter referred to as a heater) is used as the heating body 21. The heater 21 is basically composed of an elongated thin plate-like ceramic substrate whose longitudinal direction is perpendicular to the drawing in FIG. 1A and an energization heating resistor layer provided on the substrate surface. It is a low heat capacity member that rises in temperature with a steep rise characteristic when energized to the layer. The heater 21 is fixedly supported by the heater support member 22. The heater support member 22 has a substantially semicircular arc shape in cross section and is a heat insulating member such as a heat resistant resin whose longitudinal direction is the longitudinal direction in FIG. The heater 21 is placed in a groove formed along the length of the lower surface of the support member 22 so that the heater surface is exposed downward and fixed with a heat resistant adhesive or the like. A temperature detection element (not shown) such as a thermistor for detecting the heater temperature is disposed on the surface of the heater 21 on the support member side.

  The flexible sleeve 23 that is a heat transfer member is a cylindrical (endless, endless belt-like) heat-resistant resin film (fixing film: hereinafter referred to as a film) in the fixing device 10 of the present embodiment. is there. The film 23 is loosely fitted on the support member 22 including the heater 21. Reference numeral 24 denotes a stay having rigidity disposed inside the support member 22. That is, the film 23 is a flexible endless member that includes the heater 21, the support member 22, and the stay 24. As the film 23, a heat resistant resin film having a film thickness of 100 μm or less, preferably 50 μm or less and 20 μm or more can be used in order to reduce the heat capacity and improve the quick start property. For example, a monolayer film of polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), or tetrafluoroethylene / hexafluoropropylene copolymer (FEP) can be used. Uses composite film with polyimide (PI), polyamideimide (PAI), polyetheretherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS), etc. coated with PTFE, PFA, FEP, etc. it can. It can also be made of a metal with good thermal conductivity. For example, the composite layer material is a cylindrical composite material having a metal film, an elastic layer, and a release layer in order from the inside to the outside. Examples of the metal of the metal film include aluminum, nickel, copper, iron, and SUS. The elastic layer is, for example, a silicone rubber layer or a heat-resistant resin foam layer, and can improve the fixability of a thick toner layer such as a full-color image.

  The pressure roller 25 is a heat-resistant elastic roller, and includes a cored bar 25a and an elastic layer 25b made of a heat-resistant rubber such as silicone rubber or fluorine rubber, or a foam of silicone rubber. Both ends of the cored bar 25a are rotatably supported by bearings relative to an apparatus frame (not shown). Above the pressure roller 25, the assembly of the heater 21, the support member 22, the film 23, and the stay 24 is arranged in parallel with the pressure roller 25 with the heater 21 facing downward. Then, both end portions of the stay 24 are pressed downward by the urging member 26 with a predetermined pressing force F. Thus, the lower surface of the heater 21 is pressed against the upper surface of the pressure roller 25 through the film 23 against the elasticity of the elastic layer 25b, and the recording material conveyance direction is between the film 23 and the pressure roller 25. Regarding D, a nip portion (fixing nip portion) N as a heating portion having a predetermined width is formed.

  At both ends of the support member 22, flange members 31 are fitted and disposed. Each of the flange members 31 receives the film end portion on that side, and serves to regulate the movement of the film 23 along the length of the support member 22. Further, an inner flange 27 is provided on the inner surface side of each flange member 31, and the inner flange 27 enters the film from the film end opening on that side, and the inner peripheral surface of the film Receiving the edge. A is the length dimension of the film 23, B is the length dimension of the pressure roller 25 (the elastic roller portion that presses against the film 23 to form the nip portion N), and C is the maximum length of the recording material to be passed through the apparatus. Paper width. A> B> C.

  At a predetermined control timing in the image forming execution sequence control, the pressure roller 25 of the fixing device 10 is driven at a predetermined rotational peripheral speed V [mm / s] by the driving unit M, and power is supplied to the heater 21. . A rotational force acts on the film 23 due to a pressure frictional force at the nip portion N between the pressure roller 25 and the film 23 by the rotation driving of the pressure roller 25, and the film 23 slides in close contact with the downward surface of the heater 21. The outer periphery of the support member 22 is rotated. Further, the temperature of the heater 21 is detected by a temperature detection element (not shown) and fed back to a control circuit unit (not shown). The control circuit unit controls the electric power supplied from the power supply unit (not shown) to the heater 21 so that the temperature detected by the temperature detection element is maintained at a predetermined fixing temperature (target temperature). To do. In this state, the recording material P carrying the unfixed toner image t is introduced into the nip portion N, and the toner image carrying surface side of the recording material P is in close contact with the outer surface of the film 23 in the nip portion N. The nip portion N is nipped and conveyed. In this nipping and conveying process, the heat of the heater 21 is applied to the recording material P through the film 23, and the unfixed toner image t on the recording material is heated and pressurized on the recording material to be melted and fixed. The recording material P that has passed through the nip N is separated from the outer surface of the film 23 by curvature. The support member 22 also functions as a rotation guide member for the film 23. The shift in the longitudinal direction of the support member accompanying the rotation of the film 23 is regulated by the flange member 31. In order to smooth the rotation of the film 23, lubricating grease is applied to the inner surface of the film 23, and the grease is interposed between the heater surface of the nip portion N and the inner surface of the film.

  The inner peripheral length of the film 23 and the outer peripheral lengths of the heater 21, the support member 22, and the inner flange 27 are, for example, about 3 mm larger for the film 23. Therefore, the film 23 is loosely fitted on the outer circumference of the heater 21, the support member 22, and the inner flange 27 with a sufficient circumference. The tension acts only on the nip portion N, the outer surface portion of the support member 22 upstream of the nip portion N in the film rotation direction, and the film portion in the contact portion area between the inner flange 27 and the film 23 when the film is rotationally driven. No tension acts on most of the film. Therefore, the shift movement force along the length of the support member 22 of the film 23 in the film rotation driving state is small, and the shift movement restricting means or the film shift movement control means of the film 23 can be simplified. For example, the shift movement restricting means for the film 23 can be as simple as the flange member 31 for receiving the film end, and the film shift control means can be omitted to reduce the cost and size of the apparatus. it can.

(2-2) Separating member and sliding roller Here, in the following description, the upstream or upstream side and the downstream or downstream side are the upstream or upstream side and the downstream or downstream side in the recording material conveyance direction D. A recording material separation member (separation guide) 29 is disposed on the downstream side of the nip portion N (the recording material outlet side of the nipped portion N) with the tip portion facing the film 23. The separation member 29 is rotated as shown in FIG. 3A so that the recording material P coming out of the nip portion N does not wind around the film 23 and does not touch the film 23 and damage the film. It is arranged with a certain gap (gap) α from the stopped film 23. The separating member 29 is located in the inner region of the maximum sheet passing width C, and is fixedly arranged with respect to the apparatus frame (not shown) via a support member (not shown). Further, on both ends of the film 23 on the downstream side of the nip portion N, sliding rollers 28 for restricting the rotation trajectory of the film 23 in the rotation stop state are opposed to the film 23, respectively, as shown in FIG. ) As shown in FIG. α> β. The rollers 28 on both end sides of the film 23 are supported so as to be rotatable with respect to the shafts 28a attached to the support portions 31a provided on the flange members 31 on the opposite sides, respectively. It corresponds to the film end (non-sheet passing area of the film 23). Further, the facing portion of the roller 28 with respect to the film 23 is located on the upstream side of the facing portion of the separating member 29 with respect to the film 23 (the tip of the separating member 29). That is, the roller 28 is disposed at a position downstream from the nip portion N and upstream from the separation member 29. The roller 28 has a cylindrical shape, and the material is preferably polyphenylene sulfide (PPS) or polyamideimide (PAI). Here, in this embodiment, the roller 28 is positioned corresponding to both ends of the film (sleeve both ends) in the outer region of the maximum sheet passing width C of the apparatus, but the roller 28 has a maximum sheet passing width C of the apparatus. It can also be set as the structure corresponding to one of the film both ends of the outer side area | region.

  In the tensionless fixing method, rotation unevenness is likely to occur when the film 23 is rotated. When the apparatus is not sufficiently warm, such as immediately after the power is turned on, the film 23 is more likely to be uneven in rotation than when it is warm, and the film 23 swells in the recording material conveyance direction and follows a fluttering rotation trajectory. As a cause of the phenomenon that, when the apparatus is warmed up, it becomes difficult for the film 23 to flutter in the recording material conveyance direction, the following matters may be mentioned. That is, the film slip phenomenon due to the viscosity change characteristic of the grease, the rotation unevenness in the longitudinal direction of the fixing film due to the difference in thermal expansion coefficient between the film and the heater, and the fixing film due to the decrease in Young's modulus due to the temperature rise Such as a decrease in bending rigidity. Further, the film 23 interferes with the separation member 29 and the film 23 for preventing the bulging flap and the recording material from being wound around the film in the downstream side in the recording material conveyance direction. If the film surface layer is scratched by interference with the separation member 29, a scar appears on the image surface of the recording material. Therefore, the separating member 29 is arranged in a state where the apparatus is not sufficiently warmed, that is, in a position where it does not come into contact with the film 23 even when starting up. However, when the temperature of the apparatus is controlled and the rotation trajectory of the film 23 is stabilized, the gap between the film 23 and the separating member 29 is widened. For this reason, when full-color images are fixed with a relatively large amount of toner, or when fixing thin paper or moisture-absorbing paper, which is relatively weak, there is a case where a recording material wraps around. In the present embodiment, due to the above-described relationship between the roller 28 and the separation member 29, the rotation unevenness of the film 23 is reduced, and the gap between the film 23 and the separation member 29 is narrowed to improve the separation performance. That is, the roller 28 is rotated by the rotation of the film 23 by the contact of the film 23 when the rotation path of the film 23 is restricted. The temperature of the film 23 is adjusted at the beginning of the start-up of the fixing device 10 and spreads toward the downstream side in the recording material conveyance direction as described above. However, since the roller 28 regulates the rotation trajectory of the film 23, the film 23 and the separating member 29 do not interfere with each other. When the temperature of the apparatus increased and the rotation trajectory of the film 23 became stable after about 15 seconds from the start-up, the contact between the roller 28 and the film 23 disappeared, and the film 23 drawn a smooth and natural rotation trajectory.

  Here, a fixing experiment was performed using a fixing device 10 having a roller mechanism and a fixing device not having a roller mechanism as in this embodiment, and the separability of recording materials was compared. FIG. 3B compares the trajectory of the film 23 (shown by a solid line) when the fixing device is started up without providing the roller 28 and the trajectory of the film 23 at the time of stable rotation (shown by a broken line). It is a schematic diagram. (C) is a schematic diagram comparing the trajectory of the film 23 (shown by a solid line) when the roller 28 is provided in the start-up operation of the fixing device and the trajectory of the film 23 during stable rotation (shown by a broken line). . 4A is a diagram in which the rotation trajectory of the film 23 in the vicinity of the separating member 29 is recorded, and FIG. 4B is a front view of the separating member 29 when the fixing device is started up without the roller 28 provided. FIG. 6 is a diagram in which the gap fluctuation of the film 23 is recorded in time series. FIG. 6C is a diagram in which fluctuations in the gap between the tip of the separating member 29 and the film 23 are recorded in time series when the fixing device 10 is started up with a roller.

  In this experiment, in the above configuration, the film 23 is a cylindrical composite material in which a base material made of PI having a thickness of 50 μm is laminated with 200 μm of silicone rubber as an elastic layer and 50 μm of PFA as a surface layer. The diameter of the film 23 is 30 mm. As the pressure roller 25, a roller having a silicone rubber layer 25b having a thickness of 5 mm on a core metal 25a made of Al is used. The diameter of the pressure roller 25 is 30 mm. The pressure roller 25 is driven at a rotational peripheral speed of 200 [mm / s], and the film 23 is rotated at a rotational peripheral speed of 200 [mm / s] following the rotation of the pressure roller 25. A fixing nip portion N is formed by applying a 30 kgf load downward on the stay 24 by the urging member 26. For the roller 28, polyphenylene sulfide (PPS) was used. The fixing process was performed by controlling the temperature of the heater 21 at 200 ° C.

In addition, the trajectory of the warmed and stable film 23 in the above configuration was measured with a laser displacement meter, and the separation member 29 was arranged so that the gap between the film trajectory bulging most downstream and the separation member 29 was 0.5 mm. Moreover, the roller 28 was arrange | positioned in the position which suppresses the flutter to the downstream of the film 23 at the time of starting ((c) of FIG. 3). Further, the trajectory of the film 23 that fluttered most at the time of start-up was measured with a laser displacement meter without placing a roller at a position to suppress the flutter to the downstream side of the film 23 at the time of start-up. Then, it was confirmed whether or not a winding jam occurred when the separation guide was arranged so that the gap between the track and the separation member 29 was 0.5 mm ((b) in FIG. 3). The experimental environment is room temperature 30 ° C. and humidity 80%. The paper type used as the recording material is Canon EN100 (64 gsm), paper size: A4. The amount of applied image is 1.10 [mg / mm ² ]. The results are shown in Table 1.

  In the present embodiment, the sliding roller 28 that regulates the rotation trajectory of the film 23 is disposed at a position downstream from the nip portion N and upstream from the separation member 29. Thereby, the rotation trajectory of the film 23 at the time of start-up could suppress the flutter phenomenon ((c) of FIG. 3). As a result, the separating member 29 can be disposed in the vicinity of the film 23, and a full color image with a relatively large amount of toner loaded, a thin paper with relatively weakness, or a paper sheet with moisture absorbing paper can be prevented from being wound around the film 23. I was able to. Further, when the film 23 is heated and starts to be driven and the rotation path of the film 23 is stabilized, the sliding roller 28 is defined at a position and an outer diameter where the sliding roller 28 does not contact the film 23 ((c) of FIG. 3). ). That is, the position and the outer diameter of the roller 28 with respect to the film 23 are such that the roller 28 is not in contact with the film 23 in a state where the rotation path of the film 23 is stable after the rotation and heating of the film 23 are started. It is specified in the diameter. Therefore, the time during which the film 23 is restricted by the roller 28 from rotating is reduced, and the phenomenon of fatigue failure of the film 23 due to the bending of the film 23 does not occur.

[Second Embodiment]
FIG. 5A is a schematic configuration diagram of the fixing device 10 in the present embodiment. The fixing device 10 of this embodiment is characterized by having a moving mechanism 32 that allows the sliding roller 28 used in the fixing device 10 of the first embodiment to contact and separate from the film 23. In the fixing device 10, a sliding roller 28 that regulates the rotation trajectory of the film 23 is disposed at a position downstream from the nip portion N and upstream from the separation member 29. A moving mechanism (moving means: position adjusting member) 32 for adjusting the position of the roller 28 is provided. Further, temperature detection means 33 for detecting the temperature of the apparatus is provided. The temperature of the apparatus is, for example, the temperature of the film 23 or the temperature of the heater 21. In the present embodiment, as the temperature detection means 33, a temperature detection means that is disposed in the vicinity of the heater 21 and detects the temperature adjustment temperature of the heater 21 is used. Temperature information detected by the temperature detection means 33 is input to the control unit (CPU) 101. The control unit 101 determines whether the detected temperature information is equal to or higher than a predetermined temperature (100 ° C. in the present embodiment), and controls the actuator driving power source 102 of the moving mechanism 32. 5B and 5C are schematic diagrams of the configuration of the moving mechanism 32. FIG. The moving mechanism 32 includes a sliding roller 28 that regulates the rotation trajectory of the film 23, a shaft 34 that is a rotating shaft of the roller 28, a support member 35 that is connected to the shaft 34, and a telescopic member 36. The support members 35 are arranged to be slidable in directions toward and away from the apparatus frame (not shown) on both ends of the film 23, respectively. An elastic member 36 is connected to one support member 35 of the support member 35. The shaft 34 is arranged and supported in parallel with the film 23 between the support members 35 on both ends of the film 23. The rollers 28 are provided on both ends of the shaft 34 and are positioned corresponding to both ends of both ends of the film in the outer region of the maximum sheet passing width of the apparatus. The roller 28 may be configured to correspond to one of both end portions of the film in the outer region of the maximum sheet passing width of the apparatus. The expansion / contraction member 36 is a member that slides and moves in a direction in which the connection support member 35 is brought closer to the film 23 side and a direction in which the connection support member 35 is moved away from the film 23 side. As a result, the entire support member 35, shaft 34, and roller 28 are moved in a direction approaching the film 23 side and a direction away from the film 23 side. In the present embodiment, a linear solenoid that is an expansion / contraction type linear motion actuator is used as the expansion / contraction member 36, and the expansion / contraction operation is performed according to the control of the actuator drive power supply 102. When the elastic member 36 extends, the entire support member 35, shaft 34, and roller 28 slide in a direction approaching the film 23 side as shown in FIG. 5B. Accordingly, the roller 28 is held in a state where the roller 28 is in contact with the film 23 and moved to the first position G that regulates the rotation trajectory of the film 23. Further, when the elastic member 36 contracts, the entire support member 35, shaft 34, and roller 28 slide in a direction away from the film 23 side as shown in FIG. As a result, the roller 28 is held in a state of being moved to the second position H where the roller 28 is not in contact with the film 23.

  The control unit 101 performs the roller position control operation shown in the flowchart of FIG. 6A between the start of copying and the end of copying. Step 1: The roller 28 is brought into contact with the film 23 (first position G). At the initial stage when the fixing device 10 starts driving, the film 23 flutters, but the roller 28 moves to the first position and restricts the rotation trajectory of the film 23, so that the film 23 and the separating member 29 interfere with each other. There is no. Step 2: The temperature of the heater 21 increases with the passage of time from the start of driving of the fixing device 10 (temperature increase of the device). The temperature of the heater 21 is detected by the temperature detection means 33, and detected temperature data is transmitted to the control unit 101. The control unit 101 determines whether the output detected temperature is equal to or higher than a predetermined temperature (100 ° C. or higher in the present embodiment). Step 3: When the detected temperature data transmitted to the control unit 101 is equal to or higher than a predetermined temperature, the control unit 101 operates the actuator drive power source 102. As a result, the elastic member 36 contracts and the roller 28 moves to the second position H separated from the film 23. Step 4: The fixing process is started. When the temperature detected by the temperature detection means 33 is equal to or higher than a predetermined temperature, the film 23 and the separation member 29 do not interfere with each other because the rotation trajectory of the film 23 is stable.

  As described above, in the present embodiment, the temperature detection unit 33 that detects the temperature of the apparatus is provided, and the roller 28 has the first position G and the second position H according to the detection information of the temperature detection unit. Moved to. More specifically, the roller 28 is moved to the first position G when the temperature detected by the temperature detecting means 33 is lower than a predetermined temperature, and to the second position H when the temperature is higher than the predetermined temperature. By performing the above-described roller position control operation, the roller 28 and the film 23 are in contact with each other when the rotation path of the film 23 is stabilized as in the first embodiment shown in FIG. There is no need to define the position and outer diameter. That is, as shown in (c), the position of the sliding roller 28 can be arranged at a position where the fluttering of the film 23 is further suppressed, so that the separating member 29 can be arranged at a position closer to the film 29. The separability could be improved more than in the first embodiment.

Table 2 shows the results of confirming whether or not a winding jam occurred in the fixing device configuration in the present embodiment and the fixing device configuration in the first embodiment. In the fixing device configuration according to the first embodiment, the roller 28 is disposed so as to have a position and an outer diameter at which the roller 28 and the film 23 do not come into contact with each other when the rotation path of the film 23 is stabilized. The separation member 29 is arranged so that the gap (gap A in FIG. 7A) between the track swelled on the most downstream side of the film 23 and the separation member 29 is 0.5 mm. In the fixing device configuration in this embodiment, the position of the sliding roller 28 is arranged at a position where the fluttering of the film 23 is further suppressed, and the gap between the trajectory swelled on the most downstream side of the film 23 and the separating member 29 ((b) in FIG. 7). The separating member 29 is arranged so that the gap B) is 0.5 mm. The configuration of the fixing device in the present embodiment regulates the track of the film 23 by pushing the position of the roller 28 by 1 mm more than the position of the roller 28 of the first embodiment. By using NPI fine paper (52 gsm) made by NIPPON PAPER as the paper type studied, as shown in Table 2, in the fixing device configuration of the first embodiment, when the leading edge margin was 0 mm and 1 mm, a winding jam occurred. However, in the fixing device configuration of the present embodiment, no wraparound jam occurs. The experimental environment is room temperature 30 ° C. and humidity 80%. The paper type used as the recording material is NPI fine paper (52 gsm) manufactured by Nippon Paper Industries, and paper size: A4. The amount of applied image is 1.00 [mg / mm ² ].

  In the present embodiment, similarly to the first embodiment, the sliding roller 28 that regulates the rotation trajectory of the film 23 is disposed at a position downstream from the nip portion N and upstream from the separation member 29. As a result, the rotation trajectory of the film 23 when the apparatus is started up can suppress the flutter phenomenon. Further, after the film 23 is heated and started to drive, when the detected temperature of the temperature adjustment temperature becomes equal to or higher than a predetermined temperature, the expansion / contraction member 36 contracts, and the roller 28 moves in a direction away from the film 23 in conjunction with it. Accordingly, the time during which the film 23 is restricted by the roller 28 from rotating is reduced, and the phenomenon of fatigue failure of the 23 film due to the bending of the film 23 does not occur. Thereby, unlike the first embodiment, it is not necessary to define the arrangement of the rollers 28 at a position and an outer diameter at which the rollers 28 and the film 23 do not come into contact with each other when the rotation path of the film 23 is stable. Therefore, since it can arrange | position in the position which suppresses the flutter of the film 28 more, the isolation | separation member 29 can be arrange | positioned in the position closer to the film 23, and the isolation | separation property improves more than the case of 1st embodiment. We were able to.

[Third embodiment]
FIG. 8A is a schematic configuration diagram of the fixing device 10 in the present embodiment. The same components and portions as those of the first to second fixing devices 10 are denoted by the same reference numerals, and the description thereof is omitted. The fixing device 10 is disposed so as to face the film 23 downstream of the nip portion N in the recording material conveyance direction D so as to separate the recording material from the nip portion N so as not to be wound around the film 23. The separation member 29 is provided. Moreover, it has the track | orbit correction guide 40 which is arrange | positioned inside the film 23 and controls the rotation track | orbit of the film 23 so that the flutter of the film 23 may be suppressed. FIG. 8B is an enlarged view of the guide 40 portion. The guide 40 is provided inside the film 23 and above the stay 24 in parallel with the stay 24. The guide 40 has a guide member 41 that contacts the inner surface of the film 23 and regulates the rotation trajectory of the film 23. This guide member 41 is made of stainless steel (SUS), is a hollow member that is long in the length direction of the film 23, has a circular arc shape that substantially follows the inner peripheral surface of the film, and has a flat shape on the lower surface side. is there. The guide member 41 is inserted with a horizontally long plate-like support member 43 made of SUS, which is longer than the guide member 41. Further, a plurality of tension springs 44 made of SUS are provided between the upper surface of the support member 43 and the ceiling surface of the guide member 41 at intervals along the length of the support member 43. A guide position adjusting member 42 that is long in the length direction of the guide member 41 is provided between the lower surface of the support member 43 and the bottom surface of the guide member 41. The guide position adjusting member 42 is a member that receives a heat transfer from the film 23 via the guide member 41 and is heated to change the state and move the guide member 41 to a position where the guide member 41 is not in contact with the inner surface of the film 23 It is. In the present embodiment, the guide position adjusting member 42 is an air cap type member made of a polyimide resin excellent in heat resistance that changes its state when heated. FIG. 10B is an external perspective view of a part of the air cap type member 42 as the guide position adjusting member, and a plurality of air cap portions 42 a are arranged along the length of the member 42. Air is sealed in the air cap portion 42a. And the air cap part 42a expand | swells by being heated, and a state changes from before heating. FIG. 10C is an external perspective view of the guide 40 configured as described above. Both ends of the support member 43 protrude outward from both ends of the guide member 41. The guide 40 is disposed at a predetermined position inside the film 23 by the outward projecting portions at both ends of the guide member 41 being fixed to the flange member 31 on that side.

  When the device 10 is cooled to room temperature, the air cap portion 42a of the member 42 is in a state before expansion. For this purpose, the guide member 41 is moved upward from the support member 43 by the spring force of the tension spring 44. In this state, the guide member 41 is held in a state where the upper surface is in contact with the inner surface of the film 23 as shown in the left side of FIG. 8A and FIG. FIG. 9B is an operation flowchart of the guide 40 from the start of rotation and heating of the film 23 of the fixing device 10 to the start of the fixing process. In the initial stage when the fixing device 10 starts driving, the film 23 is at a low temperature, and the grease applied to the inner surface is solidified, so that the lubricity cannot be obtained, and the film 23 flutters. Therefore, when there is no guide 40, the film 23 takes a circular orbit as shown by the broken line in the left side of FIG. 9A, and the film 23 comes into contact with the separating member 29. Therefore, the guide 40 is brought into contact with the film 23, and the film 23 and the separating member 29 are corrected so that the film 23 takes a rotation trajectory as shown by the solid line in the left side of FIG. Prevent contact. That is, since the guide 40 is in contact with the film 23, the rotation trajectory of the film 23 when the apparatus is started up can be prevented from flickering. Thereafter, as the temperature of the film 23 rises, the heat of the film 2 is transmitted to the member 42 via the guide member 41 in contact with the inner surface of the film 23, and the air cap portion 42a is heated. The air cap part 42a expands by the heating. As the air cap portion 42 a expands, the guide member 41 compresses the spring 44 against the support member 43 between the upper surface of the holding member 43 and the ceiling surface of the guide member 41 against the spring force of the spring 44. It moves downward from the bottom. As a result, the guide member 41 is moved to a position where the guide member 41 is in a non-contact state with respect to the inner surface of the film 23 as shown in the right side of FIG. In the present embodiment, when the temperature of the film 23 is equal to or higher than the softening temperature of the lubricating grease applied to the inner surface of the film 23, the guide member 41 moves to a position where it does not contact the inner surface of the film 23. The relationship is configured as described above. When the temperature of the film 23 is equal to or higher than the softening temperature of the grease, the lubricity of the grease is obtained and the fluttering of the film 23 is reduced. Therefore, even when the trajectory correction guide 40 is not in contact, the circular trajectory of the film 23 is stabilized, and the film 23 takes a rotational trajectory as shown by the solid line in the right side of FIG. In the present embodiment, the design is such that the softening temperature of the grease is 100 ° C. and the volume of the air cap portion 42a is 1.25 times from normal temperature (20 ° C.) to 100 ° C. By adopting such a configuration, when the temperature of the film 23 is equal to or higher than the grease softening temperature, the air cap portion 43 a expands, and the trajectory correction guide 40 can be separated from the inner surface of the film 23. During the fixing operation of the fixing device 10 or during standby, the air cap portion 42a is heated by the radiant heat from the film 23 or the heater 21 or the hot air trapped in the inner space of the film 23. State is maintained. That is, the initial temperature of the film 23 is T1. Let V (T1) be the volume of the air cap portion 43a at the initial temperature T1. The softening temperature of the lubricating grease applied to the inner surface of the film 23 is T2. And when the volume in the said softening temperature T2 of the air cap part 43 is set to V (T2), it sets to become V (T1) <V (T2). When the power supply to the heater 21 is cut off and the apparatus temperature is cooled to a temperature lower than the softening temperature T2 of the grease, the air cap portion 42a contracts and the trajectory correction guide 40 returns to the state in contact with the inner surface of the film 23.

  FIG. 11A is a graph showing the fixing film temperature change in the case of the fixing device configuration having the trajectory correction guide 40 of the present embodiment and in the conventional example. In the conventional example, since the orbit correction guide continues to contact even after the orbit is stabilized, heat is taken away to the periphery of the fixing film, and it takes time to raise the temperature to a predetermined temperature. In this embodiment, since the track correction guide 40 is separated from the film 23 when the temperature of the film 23 is equal to or higher than the softening temperature of grease, the film 23 can be heated without taking heat away from the track correction guide 40. As a result, the rise time to the predetermined temperature can be shortened. As a result, it is possible to suppress instability of the orbit of the fixing film immediately after the start of driving and to shorten the rise time up to a predetermined temperature.

  As described above, according to the present embodiment, the trajectory correction guide 40 that stabilizes the rotation trajectory of the film 23 is brought into contact with the film 23 to perform the initial driving, thereby bringing the film 23 into contact with the separation guide 29. I was able to prevent it. When the temperature rises above a predetermined temperature, the rise time to the target temperature is shortened by separating the film 23 and the trajectory correction guide 40 by utilizing the thermal expansion of the air cap mold member 42. I was able to plan.

[Fourth embodiment]
FIG. 11B is a schematic configuration diagram of the fixing device 10 in the present embodiment. The fixing device 10 is another configuration example of the trajectory correction guide 40 in the third embodiment. The same components and portions as those of the fixing device 10 in the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. FIG. 12A is an enlarged view of a portion of the trajectory correction guide 40 in the fixing device 10 of the present embodiment. The trajectory correction guide 40 has a support member 43 made of SUS that is fixedly disposed between the flange members 31 on both ends of the film inside the film 23. A guide member 41 made of SUS is disposed on the upper surface side of the support member 43 via a guide position adjusting member 42. The guide position adjusting member 42 in the present embodiment includes a push-up spring member 42-1 made of SUS and a spring member 42-2 made of a shape memory alloy that changes its state when heated.

  When the apparatus 10 is cooled to room temperature, the spring constant of the spring member 42-2 made of a shape memory alloy is in a state smaller than the spring constant of the push-up spring member 42-1. For this purpose, the spring member 42-1 extends the spring member 42-2 and pushes the guide member 41 upward from the support member 43. In this state, the guide member 41 is held in a state where the upper surface is in contact with the inner surface of the film 23 as shown in FIG. FIG. 13A is an operation flowchart of the guide 40 from the start to the end of copying. In the initial stage when the fixing device 10 starts driving, the film 23 is at a low temperature, and the grease applied to the inner surface is solidified, so that the lubricity cannot be obtained, and the film 23 flutters. However, at the initial stage of the fixing device, as shown in the left side of FIG. 12B, the guide 40 is in contact with the film 23, so that the fluttering phenomenon of the film 23 when the device is started up is suppressed. It is done. Thereafter, as the temperature of the film 23 increases, the spring member 42-1 constituting the guide position adjusting member 42 through the guide member 41 in which the heat of the film 2 is in contact with the inner surface of the film 23. , 42-2, and the spring member is heated. In the present embodiment, the spring member 42-2 made of a shape memory alloy has a spring constant that increases when the temperature of the film 23 is equal to or higher than the softening temperature of the lubricating grease applied to the inner surface of the film. This is a member having a temperature characteristic that is larger than the spring constant and shrinks. In this embodiment, the spring member 42-2 made of a shape memory alloy has a temperature characteristic of a spring multiplier as shown in FIG. 13B, and suddenly increases at 100 ° C., which is the softening temperature of grease. Is designed to increase the spring multiplier. Accordingly, when the temperature of the film 23 becomes equal to or higher than the softening temperature of the grease and the spring member 42-2 is also heated to that temperature, the film 23 is contracted against the spring force of the push-up spring member 42-1. As a result, the guide member 41 is pulled down and moved to a position where the guide member 41 is in a non-contact state with respect to the inner surface of the film 23 as shown on the right side of FIG. When the temperature of the film 23 is equal to or higher than the softening temperature of the grease, the lubricity of the grease is obtained and the fluttering of the film 23 is reduced, so that the orbit of the film 23 is stabilized even when the track correction guide 40 is not in contact. . During the fixing operation of the fixing device 10 or during standby, the guide position adjusting member 42 is heated by radiant heat from the film 23 or the heater 21 or hot air trapped in the inner space of the film 23. The separated state is maintained. That is, the initial temperature of the film 23 is T1. The spring constant at the initial temperature T1 of the spring member 42-2 made of a shape memory alloy is defined as K (T1). When the softening temperature of the lubricating grease applied to the inner surface of the film 23 is T2, and the spring constant at the softening temperature T2 of the spring member 42-2 made of a shape memory alloy is K (T2), K (T1)> Set to K (T2). When the heater 21 is de-energized and the apparatus temperature is lowered to a temperature lower than the softening temperature T2 of the grease, the spring multiplier of the spring member 42-2 made of a shape memory alloy is reduced, so that the trajectory correction guide 40 is a film. It returns to the state which contacted the inner surface of 23.

  As described above, the guide 40 can be separated from the film 23 by increasing the force with which the spring member pulls the trajectory correction guide 40 by the change in the spring constant of the spring member 42-2. As a result, the instability of the orbit of the film immediately after the start of driving is suppressed, and the rise time can be shortened by separating after the orbit is stabilized. By contacting the film 23 with the trajectory correction guide 40 that stabilizes the rotation trajectory of the film and performing the initial driving, the contact of the film with the separation guide 29 can be prevented. When the temperature rises above a predetermined temperature, the film 23 and the trajectory correction guide 40 are separated from each other by a spring member made of a shape memory alloy whose spring constant is changed by heating. It was possible to shorten it.

  10..Image heating device (fixing device), 21..Heating body (heater), 23..Sleeve (fixing film), 25..Pressure roller, M..Drive means, N..Nip portion (fixing nip) Part), P ... recording material, t ... image, D ... recording material conveyance direction, 28 ... roller, 29 ... separation member

Claims (13)

A heating body, a flexible sleeve that can rotate while sliding on the inner surface with respect to the heating body, a pressure roller that presses against the heating body via the sleeve to form a nip portion, and Driving means for rotating the pressure roller, and by rotating the pressure roller, the sleeve is driven to rotate loosely, and an image is carried between the sleeve of the nip portion and the pressure roller. An image heating apparatus that sandwiches and conveys the recorded material and heats an image by heat from the heating body via the sleeve,
A separating member disposed on the downstream side of the nip portion in the recording material conveyance direction so as to face the sleeve, and for separating the recording material from the nip portion so as not to wind around the sleeve; A rotatable roller for restricting the rotation trajectory of the sleeve;
The image heating apparatus according to claim 1, wherein a portion of the roller facing the sleeve is located upstream of the separation member facing the sleeve in the recording material conveyance direction.   The image heating apparatus according to claim 1, wherein the sleeve includes a metal film, an elastic layer, and a release layer in order from the inside to the outside.   The position and the outer diameter of the roller with respect to the sleeve are regulated to a position and an outer diameter at which the roller does not contact the sleeve in a state where the rotation trajectory of the sleeve is stable after the rotation and heating of the sleeve are started. The image heating apparatus according to claim 1, wherein the apparatus is an image heating apparatus.   4. The image heating apparatus according to claim 1, wherein the roller is positioned corresponding to one of both end portions of the sleeve in an outer region of the maximum sheet passing width of the apparatus.   4. The image heating apparatus according to claim 1, wherein the rollers are located at both ends of the sleeve in an outer region of the maximum sheet passing width of the apparatus. A heating body, a flexible sleeve that can rotate while sliding on the inner surface with respect to the heating body, a pressure roller that presses against the heating body via the sleeve to form a nip portion, and Driving means for rotating the pressure roller, and by rotating the pressure roller, the sleeve is driven to rotate loosely, and an image is carried between the sleeve of the nip portion and the pressure roller. An image heating apparatus that sandwiches and conveys the recorded material and heats an image by heat from the heating body via the sleeve,
A separating member disposed on the downstream side of the nip portion in the recording material conveyance direction so as to face the sleeve, and for separating the recording material from the nip portion so as not to wind around the sleeve; A rotatable roller for restricting the rotation trajectory of the sleeve;
The facing portion of the roller with respect to the sleeve is located upstream of the facing portion of the separating member with respect to the sleeve in the recording material conveyance direction, and the roller contacts the sleeve and regulates the rotation trajectory of the sleeve. An image heating apparatus which is moved to a first position and a second position (H) which is in a non-contact state with the sleeve.   A temperature detection means for detecting a temperature of the apparatus is provided, and the roller is moved to the first position and the second position according to detection information of the temperature detection means. 6. The image heating apparatus according to 6.   The image heating apparatus according to claim 7, wherein the roller is moved to the first position when a temperature detected by the temperature detection unit is lower than a predetermined temperature, and to the second position when the temperature is higher than a predetermined temperature. A heating body, a flexible sleeve that can rotate while sliding on the inner surface with respect to the heating body, a pressure roller that presses against the heating body via the sleeve to form a nip portion, and Driving means for rotating the pressure roller, and by rotating the pressure roller, the sleeve is driven to rotate loosely, and an image is carried between the sleeve of the nip portion and the pressure roller. An image heating apparatus that sandwiches and conveys the recorded material and heats an image by heat from the heating body via the sleeve,
A separating member disposed on the downstream side of the nip portion in the recording material conveyance direction so as to face the sleeve, and for separating the recording material from the nip portion so as not to wind around the sleeve; A trajectory correction guide disposed on the inside of the sleeve for regulating the rotational trajectory of the sleeve;
The trajectory correction guide is in contact with the inner surface of the sleeve and regulates the rotation trajectory of the sleeve, and changes its state by receiving heat from the sleeve via the guide member and being heated. And a guide position adjusting member for moving the lens to a position where it is in a non-contact state with respect to the inner surface of the sleeve.   The image heating apparatus according to claim 9, wherein the guide position adjusting member is an air cap type member that changes its state when heated. The initial temperature of the sleeve is T1, the volume at the initial temperature of the air cap part of the air cap mold member is V, the softening temperature of the lubricating grease applied to the inner surface of the sleeve is T2, and the softening temperature of the air cap part When the volume at is V,
V (T1) <V (T2)
The image heating apparatus according to claim 10, wherein:   The image heating apparatus according to claim 9, wherein the guide position adjusting member is a spring member made of a shape memory alloy that changes state when heated. The initial temperature of the sleeve is T1, the spring constant of the spring member at the initial temperature is K (T1), the softening temperature of the lubricating grease applied to the inner surface of the sleeve is T2, and the spring constant of the spring member at the softening temperature. Is K (T2),
K (T1)> K (T2)
The image heating apparatus according to claim 12, wherein: