JP2010160222A - Image heating device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image heating device and an image forming device capable of acquiring a uniform and glossy fixed image in a short warm-up time, and securing high safety even to an unexpected trouble such as paper clogging, contamination of paper powder or dust. <P>SOLUTION: This image heating device for allowing an unfixed toner image on a recording material P to pass a nipping part Nt formed of a heating member 30 and a pressing member 60, to thereby heat and fix it as a fixed image on the recording material P, includes a microwave generation device 21. The heating member 30 generates heat by the microwave from the microwave generation device 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is mounted on an image forming apparatus such as a printer, a copying machine, or a facsimile using an electrophotographic technique or an electrostatic recording technique, and is preferably used as a heat fixing apparatus for fixing an unfixed image on a recording material. The present invention relates to a heating device and an image forming apparatus using such an image heating device.

  The image heating apparatus can also be suitably used as a gloss increasing apparatus that increases the glossiness of an image by heating the image fixed on the recording material.

  Conventionally, in an image forming apparatus, a contact heating type image heating apparatus has been widely used as an apparatus for heating and fixing an unfixed toner image formed and supported on a recording material as a permanently fixed image. In this contact heating type fixing device, a heating member (hereinafter referred to as “fixing roller”) having a surface temperature in contact with the recording material heated to a predetermined fixing temperature is brought into contact with the recording material at the nip portion. The unfixed toner image on the recording material is heat-fixed as a permanently fixed image.

  As the heating method of the fixing roller, there are an internal heating method and an external heating method (surface heating method). In the internal heating method, a heating means (heating source: heater) is disposed inside the fixing roller, and the fixing roller is heated from the inside to heat the surface of the fixing roller to a predetermined fixing temperature.

  In the external heating method, a heating unit is provided outside the fixing roller, and the fixing roller is heated from the outside to heat the surface of the fixing roller to a predetermined fixing temperature.

  In the external heating system, the fixing roller is heated from the outside by a low heat capacity heating means such as a small diameter heating roller with a built-in ceramic heater or halogen lamp, so the surface of the fixing roller can be rapidly heated. is there. Therefore, the warm-up time is shortened as compared with the internal heating type apparatus.

  For the external heating method, a contact type in which a small-diameter heating roller is brought into contact with the surface of the fixing roller has been proposed. However, in the case of the contact type, toner adhered to the fixing roller is transferred to the heating roller and contaminated. There is a problem to do. In addition, it is difficult to provide a large contact area between the heating roller and the fixing roller, and there is a problem in that heat transfer efficiency is poor and warm-up time is prolonged.

  Therefore, a method has been proposed in which the surface of the fixing roller is heated by radiation of a halogen lamp (heating means) arranged in a non-contact manner outside the fixing roller (see, for example, Patent Document 1).

  The halogen lamp itself has a small heat capacity and can rise quickly, and can efficiently transfer heat to the surface of the fixing roller by condensing radiated light using a reflective material or the like. Further, since there is no contact, there is no problem that contamination such as toner adhering to the surface of the fixing roller is transferred to the heating means and accumulated.

In addition, a method is also proposed in which an eddy current is generated in a conductor provided in the vicinity of the surface of the fixing roller by an induction heating unit disposed outside the fixing roller and heated (see, for example, Patent Document 2).
JP 2000-47507 A JP 7-295414 A

  However, in the conventional method of directly transmitting light and heat to a fixing unit using a halogen lamp, if a flammable substance such as recording material, paper dust, or dust enters between the fixing roller and the halogen lamp, it is also heated. The heated recording material may cause smoke and fire.

  In a fixing device that heats and fixes an unfixed image formed with toner on the recording material, the recording material to be heat-fixed is thin and not rigid, so the recording material sticks to the surface of the fixing roller due to the adhesiveness of the toner. There is a possibility of winding around the fixing roller. Also, paper dust and the like peeled from the paper adheres to the fixing roller. For this reason, there has been a problem that it is difficult to ensure the safety of the apparatus.

  On the other hand, in the external heating method using induction heating, a low-resistance metal member that generates an eddy current provided in the vicinity of the surface layer of the fixing roller generates heat.

  However, in recent years, image forming apparatuses have been required to have high image quality. In particular, in heat fixing apparatuses for color toner images, unfixed toner on the surface of the recording material is uniformly crushed following the unevenness of the recording material. Therefore, the surface of the fixing roller is required to have elasticity.

  If a metal layer for causing induction heating is provided on the surface of the fixing roller, the surface becomes hard and the followability is lost. In order to soften the surface, when the metal layer is provided on the inside and the outer side has an elastic layer, the heat generated from the inner metal base is transferred from the surface through the outer elastic layer, The elastic layer hinders heat transfer. For this reason, there has been a problem that the surface temperature of the fixing roller increases slowly and the warm-up time becomes long.

  The present invention has been made to solve the above-mentioned problems of the prior art.

  In other words, the object of the present invention is to obtain a uniform and glossy fixed image in a short warm-up time, and to provide high safety against unexpected troubles such as paper jams, paper dust and dust contamination. An image heating apparatus and an image forming apparatus ensured are provided.

The above object is achieved by an image heating apparatus and an image forming apparatus according to the present invention. In summary, according to one aspect of the present invention, an image that is heat-fixed as a fixed image on a recording material by passing an unfixed toner image on the recording material through a nip formed by a heating member and a pressure member. In the heating device,
Equipped with a microwave generator,
An image heating apparatus is provided in which the heating member generates heat by the microwave of the microwave generator.

According to another aspect of the present invention, in an image forming apparatus comprising: an image forming unit that forms an unfixed toner image on a recording material; and a fixing device that thermally fixes the unfixed toner image on the recording material.
An image forming apparatus is provided in which the fixing device is an image heating device having the above-described configuration.

  According to the image heating apparatus and the image forming apparatus of the present invention, it is possible to obtain a uniform and glossy fixed image with a short warm-up time, and to prevent unexpected troubles such as paper jamming, paper dust, and dust contamination. However, high safety can be ensured.

  That is, according to the present invention, microwaves are not easily absorbed by combustible materials such as paper fibers that may be mixed into the image heating apparatus, and almost only the microwave absorbing layer of the heating member generates heat. Can do. For this reason, it is possible to prevent paper dust, dust, and other smoke that may be mixed due to unforeseen troubles such as paper jams, and to ignite, and to realize a surface heating type image heating device equipped with non-contact heating means that ensures high safety be able to.

  Further, the microwave absorbing heat generating layer is provided in the vicinity of the surface of the heating member, and the temperature of the surface of the heating member can be raised in a short time by generating heat only in the vicinity of the surface.

  Furthermore, since the microwave absorption layer can be made of an elastic body, it can generate heat only in the vicinity of the surface while having sufficient elasticity on the surface of the heating member, and is uniform and glossy with a short warm-up time. It is possible to obtain a fixed image.

  Hereinafter, an image heating apparatus and an image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

Example 1
(1) Image forming apparatus 1
FIG. 1 shows a schematic configuration of a laser beam printer (hereinafter abbreviated as “printer”) 1 which is an embodiment of an image forming apparatus according to the present embodiment.

  Image information is input to the printer 1 from an image information providing device (not shown) such as a host computer provided outside the printer main body 1A. The printer 1 performs a series of image forming processes in which an image corresponding to the input image information is formed and recorded on a sheet-like recording material (recording medium) P according to a known electrophotographic system.

  The printer 1 includes an image forming means, that is, a drum-shaped rotatable electrophotographic photosensitive member (hereinafter abbreviated as “photosensitive member”) 2 as a latent image carrier, a primary charging mechanism 8, and a developing device 3. The process cartridge 4 is held. Further, a laser scanner unit (hereinafter abbreviated as “scanner”) that forms an electrostatic latent image corresponding to the image information on the outer peripheral surface of the photoconductor 2 by an exposure process corresponding to the image information input from the image information providing apparatus. .) 5 is provided. Further, a roll-shaped rotatable transfer body 6 that performs a process of transferring an image to the recording material P, and a fixing device 7 as an image heating apparatus that performs a fixing process on the recording material P that has undergone the image transfer process by heating and pressing. It has.

  The process cartridge 4 is detachably supported with respect to the printer main body 1A. When maintenance such as repair of the photosensitive member 2 and replenishment of developer to the developing device 3 is necessary, the process cartridge 4 is replaced by opening the cover 9 that is supported by the main body 1A so as to be freely opened and closed. Maintenance is speeded up and simplified.

  The primary charging mechanism 8 charges the outer peripheral surface of the rotating photoreceptor 2 to a specified potential distribution by applying a specified bias from a commercial power source or the like before the exposure processing step by the scanner 5.

  The scanner 5 outputs a laser La that is modulated in accordance with a time-series electrical digital pixel signal of image information from the image information providing apparatus. The laser La scans and exposes the charged portion of the outer peripheral surface of the photoreceptor 2 through the window 4a provided in the process cartridge body. As a result, an electrostatic latent image corresponding to the image information is formed on the outer peripheral surface of the photoreceptor 2.

  Next, a series of image forming processes in the printer 1 will be described. When the start button or the like (not shown) provided on the printer main body is pressed, the rotation of the photosensitive member 2 is started. The photoreceptor 2 is driven to rotate at a prescribed peripheral speed in the clockwise direction of the arrow. At the same time, the outer peripheral surface of the photoreceptor 2 is charged to a specified potential distribution by the primary charging mechanism 8 to which a specified bias is applied.

  Next, the charged portion of the outer peripheral surface of the photoconductor 2 is scanned and exposed by the scanner 5 in accordance with image information from the image information providing apparatus. Thereby, an electrostatic latent image corresponding to the image information is formed on the portion of the photoreceptor 2. The electrostatic latent image is developed by the developer of the developing device 3 to be visualized as a toner image.

  On the other hand, the recording material P is separated and fed from the paper feed cassette 11 by the paper feed roller 12 driven at a predetermined timing. A plurality of recording materials P are stacked and accommodated in the paper feed cassette 11. The paper feed cassette 11 is detachably supported by the printer main body 1A. The recording material P fed from the paper feed cassette 11 is fed to a transfer nip portion Tn formed between the photosensitive member 2 and the transfer member 6 by a registration roller pair 12a at a predetermined control timing, and is transferred to the transfer nip. The portion Tn is nipped and conveyed. In this nipping and conveying process, the toner image on the photosensitive member 2 side is sequentially transferred to the recording material P side by the transfer member 6.

  The recording material P that has been subjected to the transfer process is subjected to heat fixing processing of the toner image by the fixing device 7 and then passes through the fixing paper discharge unit 10 that is rotatably supported by the printer main body. 13 is discharged outside the apparatus. The discharged recording material P is stacked on a tray 14 attached to the upper surface of the printer main body 1A. As described above, a series of image forming processes is completed.

(2) Fixing device 7
FIG. 2 is a schematic cross-sectional view of the fixing device 7 that is an external heating type image heating device in the present embodiment.

  The fixing device 7 includes a fixing roller (fixing rotating body) 30 as a rotatable heating member that heats an image on the recording material at the nip portion Nt, and a rotatable pressure roller 60 as a pressure member. I have.

  The fixing roller 30 and the pressure roller 60 are arranged substantially in parallel in the vertical direction and are pressed against each other by a pressure spring (not shown) at the end. Thus, a fixing nip portion (pressure nip portion) Nt having a predetermined width is formed between them in the recording material conveyance direction.

  The fixing roller 30 is rotationally driven at a prescribed peripheral speed in the clockwise direction indicated by an arrow by a driving unit (not shown). The pressure roller 60 rotates following the rotation of the fixing roller 30. Note that the fixing roller 30 and the pressure roller 60 may be separately rotated.

  The microwave generator 21 heats the fixing roller 30 from the outside. The microwave generator 21 generates a microwave of 300 to 1500 W and a frequency of 300 MHz to 30 GHz, for example, a microwave of a frequency of 2450 MHz, from a microwave generation source such as a magnetron provided therein. The microwave generator 21 and the fixing roller 30 are arranged in a non-contact manner with a distance of 1 mm or more so that foreign matter and toner attached on the fixing roller do not transfer.

  A microwave reflecting member 22 made of a metal such as aluminum is provided around the microwave generator 21, the fixing roller 30, and the fixing device 7. Accordingly, the microwave generated from the microwave generator 21 can be prevented from leaking to other than the fixing device, and can be reflected and transmitted to the surface of the fixing roller 30.

  A microwave diffusing reflection member (not shown) is provided inside the microwave generator 21 and can uniformly irradiate the entire length of the fixing roller 30 (direction perpendicular to the drawing).

  The length dimension (direction perpendicular to the drawing) of the roller portion of the fixing roller 30 and the pressure roller 60 is larger than the maximum sheet passing width of the fixing device.

  The rotating fixing roller 30 is heated from the outside by the microwave generator 21 and given a sufficient amount of heat necessary for fixing the unfixed toner image T on the recording material P at the fixing nip portion Nt.

  As described above, after the toner image T is formed in the image forming unit, the recording material P is sent to the fixing device 7 and is introduced into the fixing nip Nt formed by the fixing roller 30 and the pressure roller 60. Nipped and conveyed. In the process in which the recording material P is nipped and conveyed through the fixing nip portion Nt, the recording roller P is heated by the fixing roller 30 for a time t per one rotation of the roller, and receives the nip portion pressure to record an unfixed toner image T. The material P is fixed by heat and pressure as a permanently fixed image.

(3) Fixing roller 30
2 and 3 show a schematic configuration of the fixing roller 30 of the present embodiment.

  The fixing roller 30 of this embodiment is a rotating body in which a single microwave absorbing layer 33 having elasticity is formed in the vicinity of the surface layer of the fixing roller. For example, a low heat conductive elastic layer (hereinafter referred to as “heat insulating elastic layer”) 32 having low heat conductivity and elasticity is formed on the outer periphery of the cored bar 31, and at least one micro layer on the outside thereof. A wave absorption layer 33 is formed, and a release layer 34 is further formed on the outside thereof.

  The cored bar 31 is made of, for example, a metal material such as aluminum, iron, or SUM material, or another rigid material such as ceramic. The metal core 31 is preferably made of a metal that does not absorb microwaves and has high reflectivity in order to concentrate microwaves on the microwave absorption layer 33 in the vicinity of the surface layer of the fixing roller. Since the core metal 31 is insulated from the surface of the fixing roller by the heat insulating elastic layer 32, its effect is small even if it has low thermal conductivity and low heat capacity, and even if its form is solid, it has a hollow cylindrical shape. There may be, and the form is not ask | required.

  The microwave absorbing layer 33 is an elastic layer in which a microwave absorbing material is dispersed and mixed in, for example, silicone rubber or fluoro rubber to form a microwave absorbing heating element.

  An example of the microwave absorbing material is carbon black. It can be dispersed in silicone rubber as a filler. As carbon black, various things, such as furnace black, acetylene black, channel black, thermal black, can be used, for example. In addition to carbon black, other microwave absorbing part substances include silicon carbide, zinc oxide, iron oxide, tin oxide, antimony intrinsic substance, ferrite material, etc., as long as they absorb and generate microwaves. Any type. Further, the shape of the filler may be any shape, and is not restricted in order to achieve the object of the present embodiment.

  The heat insulating elastic layer 32 is desirably a rubber layer having a low thermal conductivity in order to prevent heat generated in the microwave absorption layer 33 from escaping to the core 31.

  The thickness of the heat insulating elastic layer 32 formed on the outer periphery of the cored bar 31 is not particularly limited, but is 1.0 to 5.0 mm, preferably in order to have effective heat insulating properties and the heat capacity does not become too large. It is good to set it as 2.0-4.0 mm. The heat insulating elastic layer 32 may be a sponge rubber in which silicone rubber is foamed sponge, a balloon rubber in which a hollow resin balloon is blended in silicone rubber, or a solid rubber as long as it has low thermal conductivity and low heat capacity.

  The fixing roller 30 may not include the heat insulating elastic layer 32 if the cored bar 31 has a sufficiently low heat capacity, and may have at least one microwave absorbing layer 33 formed on the outer periphery of the cored bar 31.

  For example, as shown in FIG. 4, a cylindrical member in which a microwave absorbing layer 33 is formed outside a hollow aluminum core 31 and a release layer 34 is formed may be used.

  The release layer 34 is a layer having a release property that prevents adhesion of toner or the like as a surface layer of the fixing roller. For example, a microwave-absorbing release layer in which a microwave-absorbing substance is mixed in the base resin material, or a high-thermal conductivity release layer in which a high-thermal conductive filler is mixed in the base resin material, or a thickness Is a thin release layer made of a base resin of 3 to 30 μm.

  In order to efficiently transmit heat generation from the lower microwave absorption layer 33 to the surface of the fixing roller, it is desirable that the thickness is 5 to 50 μm. Alternatively, a high heat conductive filler is dispersed to give high heat conductivity. Alternatively, the microwave absorber may be dispersed and the release layer itself may generate heat.

  Examples of the base resin material include fluorine resin, polyphenylene sulfide, polysulfone, polyetherimide, polyethersulfone, polyetherketone, liquid crystal polyester, polyamideimide, and polyimide.

In the above, examples of the fluorine-based resin include polytetrafluoroethylene resin (PT
FE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (
PFA). In addition, fluorinated ethylene polypropylene copolymer resin (F
EP), polyvinylidene fluoride resin (PVDF), polyvinyl fluoride resin (PVF), and the like.

  The release layer 34 using a fluorine resin is formed of a fluorine resin coating agent, a fluorine resin tube, or the like.

The coating may be any method such as latex, Daiel latex (made by Daikin Industries, Ltd., fluorine latex), dipping coating using a dispersion, spray coating, or the like.

  When the microwave absorbing material is dispersed in the release layer 34, the same material as that used for the microwave absorbing layer 33 can be used.

  In the fixing roller 30, the release layer 34 may be formed thick as a microwave absorption layer, and the microwave absorption layer 33 made of an elastic material may be omitted. For example, as shown in FIG. 5, a cylindrical member in which a heat insulating elastic layer 32 is formed outside a hollow core 31 and a release layer 34 as a microwave absorption layer is formed may be used.

  Further, if there is a means for assisting the releasability of the surface of the fixing roller by means of an oil application means and preventing adhesion of toner or the like, the microwave absorbing layer 33 may be a surface layer and the release layer 34 may not be provided.

  That is, the fixing roller 30 may be, for example, a cylindrical member in which a heat insulating elastic layer 32 is formed on the outside of a hollow core 31 and a microwave absorbing layer 33 is formed on the outermost layer as shown in FIG. Further, for example, as shown in FIG. 7, a cylindrical member in which only the microwave absorption layer 33 is formed outside the hollow aluminum core 31 may be used.

(4) Pressure roller 60
In this embodiment, as shown in FIG. 2, the pressure roller 60 includes an elastic layer 42 and a releasable layer 43 on the outermost layer on the outer side of the cored bar 41 made of aluminum, iron, SUM, or the like. Formed.

  The pressure roller 60 forms a fixing nip portion Nt by contact pressure with the fixing roller 30.

  As with the heat insulating elastic layer 32 of the fixing roller 30, the elastic layer 42 is preferably a balloon rubber layer in which a hollow filler such as a microballoon is blended with silicone rubber or the like. Alternatively, a silicone rubber layer containing a water-absorbing polymer and a sponge rubber layer obtained by hydrogen foaming silicone rubber are desirable. If the thermal conductivity is low, a solid rubber layer may be used.

  If the cored bar 41 has a low heat capacity, the pressure roller 60 may be a rigid cylindrical member formed by forming the release layer 43 directly on the outside of the hollow cored bar 41. Since the fixing roller 30 has the elastic layer 32, the pressure roller 60 can form the fixing nip portion Nt even if it is not an elastic body.

(5) Driving Description With the above configuration, the energization of the microwave generator 21 is started in a state where the fixing roller 30 is driven to rotate and the pressure roller 60 is driven to rotate.

  FIG. 8 shows the microwave generator 21 and the energization control means 100.

  The microwave output from the microwave generator 21 is reflected directly or reflected on the reflection plate 22 and irradiated onto the surface of the fixing roller 30, absorbed by the microwave absorption layer 33, and converted into heat to generate heat. The microwaves that could not be absorbed are transmitted toward the inside, reflected by the fixing roller core 31, hit the microwave absorption layer 33 again, and are absorbed and heated. The microwave energy is absorbed by the microwave absorption layer 33 provided only in the vicinity of the surface of the fixing roller 30 to generate heat, so that energy is not used for an excessive internal temperature rise, and the surface temperature of the fixing roller 30 is reduced. Can be raised rapidly.

  The microwave is generated by a magnetron (not shown) in the microwave generator 21, and is reflected by a microwave reflector (not shown) provided in the microwave generator 21, and is evenly distributed along the length of the fixing roller 30. Is irradiated.

  The surface temperature of the fixing roller 30 is raised to a temperature necessary for heating and fixing the recording material P.

  In the present embodiment, the electric power of the microwave generator 21 is supplied from a control device (control circuit) 25 through a safety element 24 such as a thermo switch arranged near the fixing roller from a power source 26. The output of the microwave generator 21 is ON / OFF controlled by the control circuit 25.

  The safety element 24 is shielded from the microwave by a protective tube or the like that blocks the microwave, and is disposed in a non-contact manner in the vicinity of the surface of the fixing roller. Then, when the surface of the fixing roller becomes abnormally hot, the power to the control circuit 25 and the microwave generator 21 is cut off.

  A temperature detection element 23 is brought into contact with the surface of the fixing roller to detect the temperature of the surface of the fixing roller.

  The control circuit 25 controls the microwave output according to the temperature detected by the temperature detection element 23. When the temperature of the fixing roller 30 reaches the target temperature, the control device 25 turns off the microwave output.

  When the temperature is lower than the target temperature by a predetermined temperature, the output of the microwave is turned ON again, and the surface of the fixing roller 30 is controlled to become the predetermined temperature.

  With the surface of the fixing roller 30 maintained at a predetermined temperature, the recording material P on which the unfixed toner image T is formed is introduced into the fixing nip portion Nt, whereby the unfixed toner image T on the recording material P is heated and fixed. To fix images.

  The state of the toner image T and the fixing roller 30 in the fixing nip Nt at this time will be described with reference to FIG.

  In FIG. 9, when the recording material P on which the unfixed toner image T is formed is introduced into the fixing nip portion Nt, the toner image T is pressed by the surface of the fixing roller 30 and is crushed.

  At this time, since the fixing roller 30 has elasticity, the surface of the fixing roller 30 is slightly deformed corresponding to the unevenness of the toner image T. As a result, the outermost high heat conductive layer 33 of the fixing roller 30 is recessed so as to wrap the toner image T. As a result, the contact area of the fixing roller 30 increases with respect to the toner image T, and heat is efficiently transferred from the fixing roller 30 to the toner image T on the recording material P. In particular, since the fixing roller 30 is an elastic member as shown in the present embodiment, even if the toner image is on a recording material having a large surface roughness, the surface of the fixing roller 30 follows the unevenness of the recording material P. The fixing property on the recording material P can be obtained.

  Then, the toner image T on the recording material is uniformly melted and crushed, so that the surface becomes smooth and a glossy image is semi-permanently fixed to the recording material.

  The fixing device 7 according to the present exemplary embodiment can obtain an image without uneven fixing in a short first printout time. Further, there is no accumulation of toner and the like, and there is no danger of ignition and smoke, and a stable and safe fixing operation is possible.

(Experiment)
In order to confirm the quick start property and safety of the image forming apparatus in the present embodiment, an image forming apparatus 1 including the fixing device 7 in the present embodiment and an image forming apparatus including the fixing device in the conventional example are provided. The experiment was performed and confirmed.

  First, the basic configuration of the fixing device 7 used in this experiment will be described below.

The process speed of the used image forming apparatus is 100 mm / sec, and 16 per minute.
Experiments were performed using a laser beam printer that performed sheet printing.

  The fixing device 7 according to the present embodiment is an image heating device using a microwave shown in FIG.

  A microwave generator 21 having an output of 800 W is disposed in a non-contact manner with the fixing roller 30, and a microwave reflection member 22 is provided in the periphery. In the vicinity of the surface of the fixing roller 30, a thermo switch 24 that is not in contact with the fixing roller 30 and shielded from microwaves is disposed. When the temperature rises abnormally, power is cut off.

  Further, the surface temperature of the fixing roller 30 is measured using the contact-type temperature detecting element 23 for the surface temperature of the fixing roller 30 from the heating position to the fixing nip portion Nt in the rotation direction of the fixing roller 30.

  The fixing roller 30 is provided with a heat insulating elastic layer 32 made of sponge silicone rubber having a thickness of 3 mm and a thermal conductivity of 0.15 W / m · K on an iron core 31 having a diameter of 14 mm. On the outside, a microwave absorbing layer 33 having a thickness of 100 μm and having 30% by volume of carbon black dispersed in silicone rubber was provided. The surface is a rotating body provided with a release layer 34 made of a PFA tube having a thickness of 30 μm, and is rotated by a driving means (not shown).

  The pressure roller 60 has a heat insulating elastic layer 42 with a thickness of 3 mm and a thermal conductivity of 0.15 W / m · K on the cored bar 41, and a release layer 43 with a thickness of 30 μm on the surface. . The pressure roller 60 is pressed against the fixing roller 30 by a pressing unit (not shown), and is driven to rotate by the rotation of the fixing roller 30. The width w of the fixing nip portion Nt was 5 mm.

  As Conventional Example 1, a heating and fixing device is provided in which a halogen lamp is directly irradiated on the surface of the fixing roller to heat the fixing roller in a non-contact manner.

  FIG. 10 shows a schematic configuration of Conventional Example 1.

  An 800 W halogen lamp 27 is disposed so as to heat the fixing roller 30 in a non-contact manner, and the periphery is covered with a radiant light reflector 26 so that the fixing roller 30 can be effectively irradiated.

  A thermo switch 24 is disposed in the vicinity of the fixing roller 30 and shuts off the output of the halogen lamp 27 when the temperature rises abnormally. The fixing roller 30 has a heat insulating elastic layer 32 having a thickness of 3 mm and a thermal conductivity of 0.15 W / m · K on an iron core 31 having a diameter of 14 mm, and a release layer 34 provided on the outer side thereof. It is a rotating body and is rotated by a driving means (not shown). The width w of the pressure roller 60 and the fixing nip portion Nt is the same as in the embodiment.

  When the warm-up is started, the halogen lamp 27 emits light, the surface of the fixing roller 30 is heated by the emitted light, and the temperature rises. As in the embodiment, the recording material P is passed through the fixing nip portion Nt and fixed by heating.

  As a conventional example 2, an induction heating device is used to generate heat by generating an eddy current in a metal body provided inside the fixing roller.

  FIG. 11 shows a schematic configuration of Conventional Example 2.

  A coil 28 as an induction heating device is arranged so that the fixing roller 30 can be heated. Near the surface of the fixing roller 30, a thermo switch 24 is disposed in a non-contact manner, and power is cut off when the temperature rises abnormally. The output of the induction heating device 28 is 800W.

  The fixing roller 30 is a Ni cylindrical film having a thickness of 100 μm on an elastic roller having a heat insulating elastic layer 32 having a thickness of 3 mm and a thermal conductivity of 0.15 W / m · K on an iron core 31 having a diameter of 14 mm. To form a heat generating layer 35. Further, a high thermal conductive elastic layer 36 having a thermal conductivity of 1.0 W / m · K was formed on the outside with a thickness of 200 μm, and a release layer 34 with a thickness of 30 μm was provided on the outermost layer. The fixing roller 30 is rotated by a driving unit (not shown).

  The width w of the pressure roller 60 and the fixing nip portion Nt is the same as in the embodiment.

  When the warm-up is started, the coil 28 generates a magnetic field, an eddy current is generated in the metal heat generating layer 35 to generate heat, and the surface of the fixing roller 30 rises in temperature. Similarly to the embodiment, the recording material P is passed through the fixing nip portion Nt and fixed by heating.

  Conventional Example 3 is also a heating and fixing device that generates heat by generating an eddy current in a metal body provided inside the fixing roller by an induction heating device.

  FIG. 12 shows a schematic configuration of the third conventional example.

  The fixing roller 30 is a Ni cylindrical film having a thickness of 100 μm on an elastic roller having a heat insulating elastic layer 32 having a thickness of 3 mm and a thermal conductivity of 0.15 W / m · K on an iron core 31 having a diameter of 1 mm 4. To form a metal heating layer 35. A release layer 34 having a thickness of 30 μm was provided as the outermost layer. The fixing roller 30 is rotated by a driving unit (not shown).

  The width w of the pressure roller 60 and the fixing nip portion Nt is the same as in the embodiment.

  When the warm-up is started, the coil 28 generates a magnetic field, an eddy current is generated in the metal heat generating layer 35 to generate heat, and the surface of the fixing roller 30 rises in temperature. Similarly to the present embodiment, the recording material P is passed through the fixing nip portion Nt and fixed by heating.

  The recording material P on which the unfixed toner image T was formed was passed through the fixing device, and the fixing performance was evaluated.

  The experiment is started from the state in which the temperature of the fixing roller 30 and the entire fixing device is adapted to the ambient temperature (hereinafter, this condition is referred to as “cold start”). The environment during the experiment was a temperature of 25 ° C. and a humidity of 60 ° C.

  From the cold start, simultaneously with the start of rotational driving of the fixing roller 30, the power of 800 W is applied to the heating means to heat the fixing roller 30 and raise the fixing roller temperature to a target temperature at which fixing is possible.

  The temperature of the fixing roller 30 is controlled using the temperature detecting element 23, and after reaching the desired fixing roller temperature, the power of any heating means is controlled so as to maintain the target temperature.

The case where the image defect exceeded 5% of the original toner image was determined as NG (defect). As the recording material P, 4024 manufactured by XEROX and a basis weight of 75 g / m ² paper was used.

  Warm-up is performed until the surface temperature of the fixing roller 30 reaches a target temperature at which fixing is possible. When the target temperature is reached, the recording material P on which the unfixed toner image T is formed is passed.

  The fixing device in the image forming apparatus has the warm-up time in which the fixability of the image T on the heat-fixed recording material P is good in each of the experimental devices of the embodiment, the conventional example 1, the conventional example 2, and the conventional example 3. Sought and compared.

As a method for evaluating the fixing performance of the unfixed toner image T on the recording material P, the recording material P after heat fixing is used.
A cellophane tape is affixed on the toner image, pressed at a contact pressure of 0.49 N / cm ² (50 gf / cm ² ) for 1 minute, and then peeled off. Then, evaluation was performed based on the degree of image defects (defects peeled off by the tape) in the toner image at that time.

  The results are shown in Table 1.

  In the heat fixing device 7 in this embodiment, the microwave absorbing heat generating layer 33 immediately below the release layer 34 generates heat by the microwave, and the temperature only in the vicinity of the surface of the fixing roller 30 can be quickly raised. For this reason, the fixing roller temperature was raised with a warm-up time equivalent to that of the conventional example, and sufficient fixing performance could be obtained.

  In the fixing roller 30 by induction heating in the conventional example 2, the warm-up time has become long.

  In the heat fixing apparatus of Conventional Example 2, a high thermal conductive elastic layer 36 having a thickness of 200 μm is formed outside the Ni metal layer 35 that generates heat by induction heating. This high thermal conductive elastic layer 36 impedes heat transfer to the surface of the fixing roller 30 and also has an extra heat capacity, which increases the warm-up time.

  Conventional example 3 is an induction heating type heat fixing device without this 200 μm elastic layer 36. In Conventional Example 3, the warm-up time was sufficiently short. However, the release layer is provided outside the inelastic metal layer, and the surface of the fixing roller 30 does not have sufficient flexibility and elasticity.

  The toner images on the recording materials heat-fixed by each heat-fixing device were compared. The glossiness of the toner image on the recording material was measured. For the gloss measurement, a Nippon Denshoku handy gloss meter PG-1 (angle 75 degrees) was used. In addition, uneven gloss was visually confirmed.

  The results are shown in Table 2.

  In this example, a fixed image with high glossiness (gloss) was obtained. Also, gloss unevenness was small and good.

  In the fixing roller 30 in this embodiment, an elastic microwave absorbing layer 33 is formed outside a heat insulating elastic layer 32, and a flexible release layer 34 is formed with a thickness of 30 μm. Therefore, the surface of the fixing roller has sufficient elasticity. As a result, the surface of the fixing roller is elastically deformed when the recording material P is heated and pressed, follows the uneven recording material surface and the unfixed toner image surface, and can be uniformly pressed and crushed.

  In Conventional Example 3, sufficient glossiness was not obtained. This is because the fixing roller 30 in Conventional Example 3 is provided with the release layer 34 on the outside of the non-elastic Ni metal layer 35 and cannot be adhered to the surface of the recording material because it has no elasticity. Therefore, unevenness on the surface of the recording material causes unevenness in the degree of melting and crushing of the toner, and uneven glossiness also occurs in the fixed image. The entire image is distorted and sufficient glossiness cannot be obtained.

  In Conventional Example 2, since there is an elastic layer 36 of 200 μm, an image having no gloss unevenness is obtained as compared with Conventional Example 3. As the elastic layer 36 is thicker, the adhesion to the recording material is increased, and a uniform and glossy fixed image can be obtained. However, there is a problem that the warm-up time increases as the thickness increases.

  In the heat fixing device 7 in this embodiment, the elastic layer 33 itself can generate heat, and there is no need to provide a metal layer that impairs flexibility. Therefore, while forming the elastic layer 33 with a sufficient thickness, it is possible to generate heat only in the vicinity of the surface and obtain a uniform and glossy fixed image in a short warm-up time.

  In the above experiment, Conventional Example 1 can obtain a uniform and glossy image with a short warm-up time. However, in the conventional example 1 in which the surface of the fixing roller 30 is directly irradiated with the light emitted from the halogen lamp 27 and heated, when a recording material or paper dust enters between the halogen lamp 27 and the fixing roller 30, May cause ignition or smoke.

  Although the release layer 34 is provided on the surface of the fixing roller, the melted toner exhibits adhesiveness when the toner on the recording material is heated and melted, and the recording material may be wound around the surface of the fixing roller.

  Even if a separation claw or a separation guide is provided to physically prevent entry, it is difficult to install the separation claw and the fixing roller without any gap. Also, if the separation member is brought into contact with the fixing roller, the toner is adhered and accumulated, the surface of the fixing roller is scratched, and the heat of the surface of the fixing roller is taken away. The merit is lost.

  It is difficult to prevent thin paper with a thickness of several tens of micrometers and dust that gets on the recording material, and when the recording material is jammed, the recording material may be torn and a piece of paper may be hidden. It cannot be said that it is not.

  Heat fixing devices used in offices and the like are sometimes installed together with highly flammable materials such as paper, and high safety is required.

  In this example and Conventional Example 1, a safety test was performed when the recording material P was submerged inside the fixing device. Schematic diagrams are shown in FIG. 13 and FIG.

As shown in FIGS. 13 and 14, the recording material P was wound around the fixing roller 30. The wound recording material P is 4024 manufactured by XEROX, and has a basis weight of 75 g / m ² . The driving of the rotating body such as the fixing roller 30 of the fixing device is stopped. In this state, the heating means was energized, and the state until the safety device 24 worked and the power was cut off was observed.

  In Conventional Example 1, the recording material P started to smoke in 2 seconds after the start of energization, and fired in 3 seconds. Since the recording material P is directly received and heated by the radiated light of the halogen lamp 27, the recording material P having a small heat capacity rises in a short time and ignites.

  In the heat fixing device 7 in this embodiment, the recording material P did not ignite or smoke, and the thermoswitch 24 was activated in about 5 seconds, and the power could be safely cut off. This is because the emitted light from the halogen lamp is easily absorbed by the recording material, whereas the microwave is difficult to be absorbed by the recording material.

  The recording material P used in the image forming apparatus is generally paper, OHT, gloss film, or the like whose main material is fiber. Paper consists of fibers, materials such as calcium carbonate and talc, and minute size materials, and does not contain substances that strongly absorb microwaves. The paper contains 5% by mass to 10% by mass of water, and the water molecules are vibrated by microwaves and generate heat, but the generated water is released as water vapor. A recording material with a large amount of moisture absorbed does not ignite due to a large amount of moisture, and a recording material with a small amount of moisture hardly generates heat.

  OHT and gloss films are mainly made of plastics such as PET, and generate little heat generated by absorption by microwaves.

  For this reason, in the heat fixing device 7 in this embodiment, even if a foreign matter such as a recording material enters between the heating means (microwave generator 21) and the fixing roller 30 due to an unexpected trouble, it does not cause ignition or smoke. Safety can be ensured.

  As described above, in the heat fixing device 7 in this embodiment, the elastic layer 33 itself generates heat by using microwaves, so that only the vicinity of the surface generates heat while fixing the surface of the fixing roller with sufficient elasticity. The temperature of the roller surface can be raised in a short time. Accordingly, it is possible to obtain a uniform and glossy fixed image with a short warm-up time.

  In addition, the microwave generator 21 is not easily absorbed by combustible materials such as paper fibers that may be mixed into the fixing device 7, and generates almost only the microwave absorbing layer 33 near the surface of the fixing roller. Can do. Therefore, high safety can be ensured against unexpected troubles such as paper jams, paper dust, and dust contamination.

Example 2
FIG. 15 shows a second embodiment of the image heating apparatus according to the present invention.

  In this embodiment, the fixing device 7 includes a belt-like fixing belt (fixing rotator) 30 constituting a rotatable heating member that heats an image on a recording material at the nip portion Nt, and a rotatable addition member. And a pressure member 60. As the pressure member 60, the one used in the first embodiment such as a pressure roller can be used.

  That is, in this embodiment, the fixing belt 38 fitted outside the support body 59 is used as a heating member, and the support body 50 and the fixing belt 38 are brought into pressure contact with the pressure roller 60 to form the fixing nip portion Nt. The recording material P is passed through the fixing nip portion Nt, and heat fixing is performed while the recording material P is nipped and conveyed. The fixing belt 38 is driven by a rotatable pressure member 60.

  The fixing belt 38 includes an endless belt base layer 39 made of a resin material having a high heat resistance such as PPS, polyimide, and polyamideimide having a thickness of about 30 μm to 500 μm and a low thermal conductivity. On this base layer 39, similarly to Example 1, a microwave absorbing elastic layer 33 in which a microwave absorber is dispersed in silicone rubber is provided with a thickness of 100 μm to 500 μm, and the outermost layer has a thickness of 10 μm to 30 μm. A release layer 34 made of a fluororesin layer or the like is provided.

  The endless belt base layer 39 is preferably made of a resin having heat resistance and low thermal conductivity, such as PPS, polyimide, and polyamideimide, in order to suppress the escape of heat to the inside and reduce the heat capacity. Further, the base resin is preferably a substance that transmits or reflects microwaves, and it is desirable to avoid mixing substances that easily absorb microwaves, such as carbon and oxides. When the endless belt base layer 39 is made of a metal thin film such as SUS or Ni, the thermal conductivity and heat capacity increase, but the microwave irradiated from the surface of the fixing roller and reflected by the microwave absorption layer is reflected. The microwave absorption layer can be irradiated again. However, even if the internal support 59 is made of metal, it is possible to reflect the microwave and irradiate the microwave absorption layer again.

  As the materials used for the microwave absorption layer 33 and the release layer 34, those used in Example 1 can be used.

  The support body 59 is formed by, for example, forming a heat insulating member or a heat insulating layer 51 on the support body 50. The support 50 is preferably made of a metal such as SUM, SUS, or AL material that easily reflects microwaves. The microwave that is irradiated onto the surface of the fixing belt 38 and is not completely absorbed by the microwave absorbing layer 33 is reflected toward the fixing belt 38 and can be irradiated again to the microwave absorbing layer 33.

  The fixing member 59 and the pressure member 60 are brought into contact with each other with a predetermined pressure to form the fixing nip portion Nt. In the fixing nip portion Nt, the surface of the fixing belt 38 and the surface of the pressure roller 60 are rotated and the recording material P is nipped and conveyed, and heat and pressure are applied to the recording material P to fix the toner image on the recording material P. .

  The heat insulating layer 51 may be, for example, an elastic member made of silicone rubber, fluorine rubber, or the like, and is a rigid body formed of a heat resistant resin such as liquid crystal polymer, phenol resin, PPS, PEEK, polyimide, polyamideimide, and fluorine resin. It may be a member.

  Since the heat escape from the inner surface of the fixing belt is reduced and the temperature of the fixing belt 38 is increased, the heat conductivity of the heat insulating layer 51 is preferably low.

  In the present embodiment, the surface of the support 51 that is pressed against the pressure roller 60 via the fixing belt 38 and forms the fixing nip portion Nt is configured to include a curved surface, and the amount of deformation of the pressure roller 60 is reduced while fixing. The nip portion Nt is configured to be wide.

  The surface of the support 51 may be flat or may be composed of a plurality of members. Moreover, you may attach a protrusion and provide unevenness | corrugation. A configuration in which a tension roller is provided inside the fixing belt may be employed.

  The fixing belt support 51 and the built-in fixing belt in the heat fixing apparatus 7 in this embodiment are pressed against the pressure member 60 via the fixing belt 38 to form the fixing nip portion Nt. The shape and configuration are not limited as long as the temperature rise is not significantly prevented.

  As in the first embodiment, the microwave absorbing layer 33 formed in the vicinity of the surface of the fixing member is heated by the microwave generated from the microwave generator 21, so that the fixing belt surface temperature can be rapidly raised. . The fixing belt 38 has a configuration in which a thin and flexible release layer 34 is formed outside the microwave absorbing layer 33 having sufficient elasticity. Therefore, the surface of the fixing belt closely adheres to the unevenness of the recording material, and the unfixed toner on the recording material is uniformly melted and crushed to obtain a fixed image without uneven gloss.

  Further, by using the heating member 30 as a belt member having a low heat capacity, a more rapid temperature increase is possible.

  In addition, by using the heating member 30 as a flexible belt member, the fixing nip portion Nt can be formed widely without causing the pressure roller 60 to be greatly elastically deformed. Since the contact time between the heating member 30 and the recording material P can be lengthened and heated and pressurized for a long time, the toner image surface on the recording material can be melted more smoothly and a more glossy fixed image can be obtained. be able to. Even in a heat fixing apparatus that performs heat fixing processing at high speed, a sufficient heating time can be secured.

Example 3
FIG. 16 shows a third embodiment of the image heating apparatus according to the present invention.

  In the present embodiment, the fixing device 7 has substantially the same configuration as that of the first embodiment. However, as shown in FIG. 16, the pressure member 60 that forms the fixing nip portion Nt with the fixing roller 30 is externally fitted to the support 57 and rotates around the support 57 according to the rotation of the fixing roller 30. It is assumed that the belt-shaped pressure belt 56 is included.

  The support 57 is obtained by forming a heat insulating member or a heat insulating layer 53 on a support 52 made of, for example, a SUM material. A belt 56 having a low heat capacity and low heat conductivity is fitted on the outer periphery.

  The pressure member 60 and the fixing roller 30 are brought into contact with each other with a predetermined pressure to form the fixing nip portion Nt. In the fixing nip portion Nt, the recording material P is nipped and conveyed while the surface of the fixing roller 30 and the pressure belt 56 are rotated, and the toner image on the recording material P is fixed by applying heat and pressure to the recording material P.

  The heat insulating support 53 may be an elastic member made of, for example, silicone rubber or fluorine rubber. However, since the surface of the fixing roller is an elastic body, even if the heat insulating support 53 is a rigid member, the fixing nip portion Nt. Can be secured. That is, the heat insulating support 53 may be a rigid member formed of a heat resistant resin such as a liquid crystal polymer, a phenol resin, PPS, PEEK, polyimide, polyamideimide, or a fluorine resin.

  The pressure belt 56 is, for example, a fluororesin layer having a thickness of about 10 μm to 30 μm on a base layer 54 made of a resin material having a high heat resistance and a low thermal conductivity such as PPS, polyimide, and polyamideimide having a thickness of about 30 μm to 500 μm. A release layer 55 made of is provided.

  A lubricant such as silicone oil is interposed between the support 53 and the pressure belt 56 to improve the slidability of the belt. The pressure belt support and the built-in pressure belt in the heat fixing apparatus of the present embodiment are pressed against the heating member 30 via the pressure belt 56 to form the fixing nip portion Nt. As long as the temperature rise of the heating member is not significantly hindered through the shape, the shape and configuration are not limited.

  Further, similarly to the second embodiment, the heating member 30 may have a fixing belt configuration. This schematic configuration is shown in FIG.

  In this case, the fixing belt 38 that is externally fitted to the support 59 and the pressure belt 56 that is externally fitted to the support 57 are brought into pressure contact to form the fixing nip portion Nt. The pressure belt 56 is driven by driving rollers 70 and 71 provided inside the pressure belt, the fixing belt 38 is driven to rotate, and the recording material P is nipped and conveyed at the fixing nip portion Nt while heating. Fix it.

  The driving roller may be provided inside the fixing belt 38, inside the pressure belt 56, or both.

  The effect of this embodiment is the same as that of Embodiment 1 and Embodiment 2. However, the fixing device using the pressure belt 56 in this embodiment uses the pressure member 60 as a low heat capacity belt member. More rapid temperature rise is possible.

  Further, by making the pressure member 60 a flexible belt member, the fixing nip portion Nt can be formed widely without causing the fixing roller 30 to be elastically deformed. The contact time between the heating member 30 and the recording material P can be increased, and heating and pressurization can be performed for a long time. Therefore, the toner image surface on the recording material can be melted more smoothly and a fixed image with higher gloss can be obtained. Even in a heat fixing apparatus that performs heat fixing processing at high speed, a sufficient heating time can be secured.

  Each of the above examples is an example of the best mode of the present invention, but the present invention is not limited only to the configurations shown in these examples. In other words, the image heating apparatus of the present invention is not limited to the heat fixing apparatus of the embodiment, and an image heating apparatus that modifies the surface properties such as gloss by heating a recording material carrying an image, an image heating apparatus that is supposed to be worn, etc. It can be used as an apparatus for heat-treating a recording material carrying an image.

1 is a schematic configuration diagram of an embodiment of an image forming apparatus according to the present invention. It is a schematic block diagram of one Example of the image heating apparatus which concerns on this invention. It is a perspective view which shows one Example of a heating member. It is a schematic block diagram of the other Example of a heating member. It is a schematic block diagram of the other Example of a heating member. It is a schematic block diagram of the other Example of a heating member. It is a schematic block diagram of the other Example of a heating member. It is a schematic block diagram explaining the drive control aspect of an image heating apparatus. FIG. 4 is a diagram illustrating a toner image fixing state in the image heating apparatus. It is a schematic block diagram which shows an example of the conventional image heating apparatus. It is a schematic block diagram which shows an example of the conventional image heating apparatus. It is a schematic block diagram which shows an example of the conventional image heating apparatus. It is the schematic diagram which showed the safety test method in the image heating apparatus of one Example of this invention. It is the schematic diagram which showed the safety test method in the conventional image heating apparatus. It is a schematic block diagram of the other Example of the image heating apparatus which concerns on this invention. It is a schematic block diagram of the other Example of the image heating apparatus which concerns on this invention. It is a schematic block diagram of the other Example of the image heating apparatus which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Photoconductor 7 Heat fixing apparatus 21 Microwave generator 22 Micro reflection member 23 Temperature detection element 24 Safety element 25 Microwave control circuit 26 Power supply 30 Fixing roller (heating member)
31 Core Bar 32 Low Thermal Conductive Elastic Layer 33 Microwave Absorbing Layer 34 Release Layer 39 Fixing Belt 38 Fixing Belt Base Layer 41 Core Bar 42 Elastic Layer 43 Release Layer 54 Pressure Belt Base Layer 55 Pressure Belt Surface Layer 56 Pressure Belt 57 Support Body 59 Support 63 Pressure roller (Pressure member)
Nt Fixing nip P Recording material T Toner image

Claims (13)

In an image heating apparatus that heat-fixes an unfixed toner image on a recording material as a fixed image on the recording material by passing through a nip formed by a heating member and a pressure member.
Equipped with a microwave generator,
The image heating apparatus, wherein the heating member generates heat by the microwave of the microwave generator.   The image heating apparatus according to claim 1, wherein the microwave generator is disposed outside the heating member and irradiates the heating member with microwaves.   The image heating apparatus according to claim 1, wherein a member that reflects microwaves to the heating member is provided around the microwave generation apparatus.   The image heating apparatus according to claim 1, wherein the heating member includes a microwave absorption layer in the vicinity of the surface of the heating member.   The image heating apparatus according to claim 1, wherein the heating member is a rotating body in which at least a microwave absorption layer is formed on a cored bar.   The image heating apparatus according to claim 1, wherein the heating member is a belt member in which at least a microwave absorption layer is formed on an endless belt.   The image heating apparatus according to claim 5, wherein the microwave absorption layer is formed near a surface of the heating member.   The image heating apparatus according to claim 4, wherein the microwave absorption layer is an elastic body.   The image heating apparatus according to claim 4, wherein the microwave absorption layer is an elastic body in which a microwave absorber is mixed in silicone rubber or fluorine rubber.   The image heating apparatus according to claim 1, wherein the heating member includes a surface layer containing a fluorine-based resin in which a microwave absorber is mixed on the surface of the heating member.   The image heating apparatus according to claim 10, wherein the microwave absorber is carbon black.   The image heating apparatus according to claim 1, further comprising a member that reflects microwaves inside the heating member. In an image forming apparatus comprising: an image forming unit that forms an unfixed toner image on a recording material; and a fixing device that thermally fixes the unfixed toner image on the recording material.
The image forming apparatus according to claim 1, wherein the fixing device is an image heating device according to claim 1.

Images