JP2001215825A - Image heating device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image heating device and an image forming apparatus capable of surely separating a heated material, stably performing an image heating processing without causing jamming, and preventing a rotary pressure member from being damaged. SOLUTION: In the image heating device having a rotary heating member, a magnetic flux generating means for forming a closed magnetic circuit between the rotary heating member and the generating means, the rotary pressure member and a heated member separating means arranged to be abutted on or adjacent to the rotary heating member on the downstream side of a press contact nip part in the rotary pressure member rotating direction, when L denotes a line connecting between the rotary pressure member and the center of the rotary heating member in a cross section orthogonal to the rotary shaft of the rotary heating member, θ [rad] denotes an angle formed by a line connecting between the downmost-stream position in the rotary heating member rotating direction where a magnetic line of force constituting the closed magnetic circuit passes and the line L and ϕ [rad] denotes an angle formed by the line connecting the abutting or adjacent position of the separating means and the center of the rotary heating member and the line L, the following expression is satisfied: θ-ϕ<=π/36.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image heating apparatus for heating a material to be heated using electromagnetic induction, and an image forming apparatus including the image heating apparatus, such as an electrophotographic copying machine, a printer, and a facsimile. That is, an unfixed toner image formed directly or indirectly on the surface of a recording material using a toner made of a heat-meltable resin or the like by an appropriate image forming process means such as electrophotography, electrostatic recording, or magnetic recording. And an apparatus for performing heat fixing processing as a permanently fixed image on a recording material surface.

[0002]

2. Description of the Related Art An electrophotographic copying machine or the like is provided with a fixing device for fixing a toner image transferred onto a sheet such as recording paper or a transfer material as a recording medium onto the sheet. The fixing device includes, for example, a fixing roller also referred to as a heating roller that thermally melts toner on a sheet, and a pressure roller that presses against the fixing roller to sandwich the sheet. The fixing roller is formed in a hollow shape, and a heating element is held on a central axis of the fixing roller by holding means. The heating element is formed of, for example, a tubular heating heater such as a halogen lamp, and generates heat when a predetermined voltage is applied. Since this halogen lamp is located on the center axis of the fixing roller, the heat generated from the halogen lamp is uniformly radiated to the inner wall of the fixing roller,
The temperature distribution on the outer wall of the fixing roller becomes uniform in the circumferential direction. The outer wall of the fixing roller is heated until its temperature reaches a temperature suitable for fixing (for example, 150 to 200 ° C.).
In this state, the fixing roller and the pressure roller rotate in opposite directions while being pressed against each other, and sandwich the sheet on which the toner image is formed. At a pressure contact portion (hereinafter also referred to as a nip portion) between the fixing roller and the pressure roller, the toner on the sheet is melted by the heat of the fixing roller, and is fixed to the sheet by the pressure applied from both rollers.

However, in the above-described fixing device having a heating element composed of a halogen lamp or the like, since the fixing roller is heated by using radiant heat from the halogen lamp, the temperature of the fixing roller is reduced after the power is turned on. It takes a relatively long time to reach a predetermined temperature suitable for fixing (hereinafter referred to as "warm-up time"). During that time, the user cannot use the copier, and there is a problem that the user has to wait for a long time. On the other hand, if a large amount of power is applied to the fixing roller in order to shorten the warm-up time and improve the operability of the user,
There has been a problem that the power consumption of the fixing device is increased, which is against energy saving. For this reason, in order to increase the value of products such as copiers, attention and emphasis has been placed on achieving both energy saving (low power consumption) of the fixing device and improvement in user operability (quick print) of the fixing device. Is coming.

As a substitute for such a fixing device, a film heating type fixing device using a heat-resistant film and a heating element such as a ceramic heater has been proposed. In order to further improve the thermal efficiency, Japanese Patent Application Laid-Open No. Sho 59-33787 has been proposed. As disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, a film heating type fixing device that heats by generating eddy current using high-frequency electromagnetic induction as a heating source has been proposed. In addition, in order to obtain the same effect without driving a film which is difficult to convey, a coil is concentrically arranged inside a hollow thin fixing roller made of a metal conductor, and a high-frequency current is caused to flow through this coil. There has also been proposed a method in which an induced eddy current is generated in a fixing roller by a high-frequency magnetic field, and the fixing roller itself generates Joule heat by the skin resistance of the fixing roller itself. According to the fixing device of the induction heating system, the use of a thin fixing roller greatly improves the electric-heat conversion efficiency, so that the warm-up time can be reduced.

On the other hand, in a conventional fixing device having a heat fixing roller, a silicone oil is applied to the fixing roller in order to improve the releasability of the toner and the fixing roller and to improve the durability of the fixing roller and the pressure roller. A release agent such as is applied. By applying the release agent, in the conventional fixing device, 1) the cost increases due to the oil application mechanism. 2) Dirt due to oil leakage occurs.

In recent years, toners having improved releasability of toners themselves have been developed, and oil-less fixing has been promoted.

[0007]

However, even in the case where oil-less operation is attempted as described above, a separating claw that comes into contact with the fixing roller is provided to separate the transfer material from the fixing roller. When the contact force of the separation claw on the fixing roller is large, a claw mark is generated on the copy paper after fixing, or a claw scratch is left on the fixing roller, thereby causing an image defect. Further, when the contact force of the separation claw on the fixing roller is weak, there has been a problem that the separation claw cannot completely separate the transfer material and cause a paper jam.

Accordingly, the present invention has been made to solve the above problems and to surely separate a material to be heated, to perform an image heating process stably without causing a jam or the like, and to provide a rotating and pressing member of a separating means. It is an object of the present invention to provide an image heating apparatus and an image forming apparatus capable of setting the contact pressure of the image forming apparatus to a low value and preventing the rotation pressing member from being damaged.

[0009]

An image heating apparatus and an image forming apparatus according to the present invention have the following features to solve the above-mentioned problems.

[1]: a rotary heating member, and a magnetic flux generating means disposed in the rotary heating member to generate a magnetic flux to form a closed magnetic path between the rotary heating member and induce heat generation of the rotary heating member. A rotary pressing member that presses against the rotary heating member to form a pressure contact portion, and is disposed in contact with or close to the rotary heating member on the rotation direction downstream side of the rotary pressing member from the pressing nip portion. An image heating apparatus having a member to be heated separated and heating an image on the material to be heated by introducing and heating the material to be pressed into the press contact portion, wherein the rotation axis is orthogonal to the rotation axis of the rotation heating member. In the cross section, a line connecting the center of the rotary heating member and the center of the rotary heating member is denoted by L, a line connecting the centers of the rotary pressing member and the rotary heating member, and a line of magnetic force forming the closed magnetic path passing through the most downstream position in the rotation direction of the rotary heating member. , The angle θ with the line L
[Rad] is an angle Φ [r formed by a line connecting the contact or proximity position of the separating means to the center of the rotary heating member and the line L.
ad], wherein θ-Φ ≦ π / 36.

[2]: a rotary pressing member, a rotary heating member for nipping and conveying the material to be heated at a press contact portion with the rotary pressing member,
Separating means for separating a material to be heated which is in contact with or close to the rotary heating member and which is in close contact with the rotary heating member, wherein the separation member is located on the opposite side of the material to be heated across the rotary heating member. At least one exciting coil for generating an alternating magnetic field for generating an eddy current, and a high permeability member for guiding a magnetic flux by the exciting coil in a circumferential direction of the rotary heating member to form a substantially closed magnetic path. A line L connecting the center of the rotation pressing member and the rotation heating member, and a line of main magnetic force emitted in the direction of the rotation heating member in the vicinity of the pressure contact portion by the high magnetic permeability member, at the most downstream in the rotation direction of the rotation heating member. An angle θ [rad] formed by a certain main magnetic force line is an angle Φ [rad] formed by the line L and a line connecting the contact or proximity position of the separating means and the center of the rotary heating member, and θ−Φ ≦ π / 36. An image characterized by the formula: Heat equipment.

[3]: The angle θ [rad] is 7/36
The image heating apparatus according to [1] or [2], wherein π ≦ θ ≦ π / 3.

[4]: The heating portion of the rotary heating member is a conductive hollow pipe, and has a release layer on the surface of the rotary heating member, [1], [2] or [3]. ] The image heating apparatus according to the above.

[5] The image heating apparatus according to any one of [1] to [4], wherein the separation means is a separation claw that contacts a rotary heating member.

[6]: A heat-softening colored powder image is formed on a recording material, and the recording material carrying the powder image is used as a material to be heated, as described in any one of [1] to [5]. An image forming apparatus, wherein the image is formed by fixing the powder image as a permanent image on the recording material by passing the powder image through the image heating device.

<Operation> According to the constitutions of [1] and [2], in the vicinity of a position where a region where heat is generated by electromagnetic induction of the rotary heating member (heat generation region) changes to a non-heat generation region, there is an effect of cooling separation. Since the heating material is easily separated, the material to be heated can be reliably separated by disposing the separation means at this position or at a position downstream of this position in the rotation direction of the rotary heating member. This makes it possible to set a low contact pressure when the separating unit is brought into contact with the rotary heating member, and it is possible to prevent the rotary heating member from being scratched.

According to the configuration [3], the material to be heated can be surely separated and, at the same time, the heating at the press contact portion can be efficiently performed. In addition, since the position of the separating unit does not increase, for example, there is no decrease in the paper discharging property for paper with stiffness.

According to the configuration [4], since the rotary heating member has at least the resistance layer and the release layer on the surface, the transfer material can be stably transported, and the offset is prevented by the release layer. You.

According to the configuration [5], the separation member is a separation claw that comes into contact with or is cut off by the rotary heating member, so that the transfer material can be separated with a simple configuration.

According to the configuration [6], a heat-softening colored powder image is formed on the recording material, and the recording material on which the powder image is carried is moved to any one of the above [1] to [5]. Since the toner image is passed through one image heating device, the powder image is satisfactorily fixed as a permanent image on the recording material by sufficient heating, and a good image formation without clogging of the recording material is achieved by efficient separation. Do.

[0021]

(Embodiment 1) Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view schematically showing an induction heating fixing device according to Embodiment 1 of the present invention.

The fixing roller (rotary heating member) 1 has an outer diameter of 40.
In order to enhance the releasability of the surface of an iron core metal cylinder having a thickness of [mm], a thickness of 0.7 [mm] and a length of 340 [mm], an area of 320 [mm] in the central portion which is a paper passing area. For example, PTFE10
To 50 [μm] or PFA 10 to 50 [μm].

The pressure roller (rotating pressure member) 2 is composed of a hollow cored metal 14 and an elastic layer formed of a surface-releasable heat-resistant rubber layer (surface length 325 [mm]) having a thickness of 5 mm formed on the outer peripheral surface thereof. 15 Bearing portions are formed at both ends of the pressure roller 2, and are rotatably attached to a fixing unit frame (not shown). The fixing roller 1 and the pressure roller 2 are rotatably supported, so that only the fixing roller 1 is driven. The pressure roller 2 is in pressure contact with the surface of the fixing roller 1 and is arranged so as to be driven to rotate by a frictional force at a pressure contact portion (nip portion) N. The pressure roller 2 is pressed in the rotation axis direction of the fixing roller 1 by a mechanism (not shown) using a spring or the like. The pressure roller 2 is about 294 [N]
In this case, the width (nip width) of the press contact portion is about 6 [mm]. However, depending on circumstances, the nip width may be changed by changing the load.

Exciting means is disposed inside the fixing roller 1 to generate electromagnetic pressure and heat at a pressure contact portion (fixing nip portion) of the fixing roller 1. This heating principle will be described with reference to FIG.

In this embodiment, the exciting means is an exciting coil 3
A magnetic flux 33 generated by a current applied to the exciting coil 3 by the exciting circuit 16 is guided to the core metal of the fixing roller 1 by the high magnetic permeability core 4 and is substantially closed magnetic circuit. The magnetic flux 33 generates an eddy current 34 in the cored bar. Joule heat is generated by the eddy current 34 and the specific resistance of the fixing roller (core metal).

The exciting coil 3 is wound around the core 4 so that P
It is disposed inside a holder 5 made of a heat-resistant resin such as PS, PEEK, or phenol resin. An alternating current of 10 to 100 [kHz] is applied to the exciting coil 3.

In order to increase the heat generated by the alternating current, the number of turns of the exciting coil 3 is increased, the T-type core 4 is made of ferrite or permalloy having a high magnetic permeability and a low residual magnetic flux density, It is better to increase the frequency.

In this embodiment, the T-shaped core 4 is formed and arranged by the core 401 and the core 402 for guiding the magnetic field lines in the direction of the nip, and the conductive wire constituting the exciting coil 3 is formed on the inner surface of the fixing roller 1 in the longitudinal direction (perpendicular to the paper surface). Are arranged close to each other. In this case, the lines of magnetic force forming a closed magnetic path via the fixing roller 1 and the core 4 are as shown in FIG. 3, and the distribution of heat generated in the core of the fixing roller is as shown in FIG.

The temperature sensor 6 is disposed so as to abut on the central portion in the longitudinal direction of the surface of the fixing roller 1, and the power supply to the exciting coil 3 is increased or decreased based on the detection signal of the temperature sensor 6 so that the fixing roller 1 is automatically controlled so that the surface temperature becomes a predetermined constant temperature.

The transfer material P carrying the unfixed toner image (thermosoftening colored powder image) 8 is conveyed by the conveyance guide 7 and guided by the entrance guide 20 to fix the fixing roller 1 and the pressure roller 2. The toner image 8 is heated and fixed by the heat of the fixing roller 1 while being conveyed by the rotation of the fixing roller 1 while being brought into close contact with the fixing roller 1. The transfer material P after fixing is peeled off from the fixing roller 1 by a separation claw 10 arranged so that the leading end thereof is in contact with the fixing roller 1, and guided by a discharge lower guide 21 and a discharge upper guide 22 to form an upper discharge roller 23. The sheet is sent by the lower sheet discharge roller 24 and discharged from the heating device.

The separation claw 10 used in the present embodiment is made of a heat-resistant resin such as polyimide, polyamide-imide or the like.
The tip of the claw in contact with the fixing roller has an R of about 30 μm.
It has a shape. Further, it is in contact with the fixing roller at a constant pressure by being urged by a spring (not shown).

Hereinafter, the arrangement of the T-shaped core 4 and the separation claw 10 which are the excitation means in this embodiment will be described. Table 1 shows the separation state of the separation claw 10 when the positional relationship is changed. As an image forming apparatus, a case is described in which an image forming apparatus having a printing speed of 30 sheets of A4 size paper (64 g / m ² ) per minute forms a solid black image with a leading end margin of 2 mm. Here, the contact pressure of the separation claw 10 against the fixing roller 1 is 5 g or 20 g.

As shown in FIG. 5, a line (referred to as a center line) connecting the centers of the fixing roller 1 and the pressure roller 2 in a plane perpendicular to the rotation axis of the fixing roller 1 is denoted by L, and the core 4
01, the magnetic force lines guided by the one located downstream of the nip (that is, the fixing roller 1 through which the magnetic force lines 33 forming the closed magnetic path pass).
, The angle between the center line L and the line (line connecting the most downstream position a1 in the rotation direction and the center o of the fixing roller) and θ
Is an angle formed by a center line L and a line connecting the position b1 contacting the fixing roller surface to the fixing roller 1 and the center line L.

Here, it is currently fixed at θ = π / 2.

[0035]

[Table 1]

Evaluation of Separability ◎: Separation without touching nails ○: Separation by nails △: Separation while being hooked on nails ×: Jamming caused by nails From the results in Table 1, when angle Φ is larger than angle θ, ie, separation When the position of the claw 10 is on the downstream side of the magnetic flux guided by the core 401, the fixing roller does not generate heat in the vicinity of the separation claw. Further, when Φ is smaller than θ even at the contact pressure of 5 g, the surface temperature of the fixing roller becomes high, so that the separability at the separation claw position is deteriorated, but θ-Φ is in the range up to π / 36. In this case, separation by the nail can be performed without any problem. This contact pressure is a pressure that does not damage the fixing roller, does not damage the fixing roller, and facilitates separation when θ−Φ ≦ π / 36.

Next, in the present embodiment, θ−Φ = π / 3
Table 2 shows the separability when the angle of the magnetic field lines guided by the core 401 and the center line of the roller were changed while the angle was fixed at 6. In the evaluation of the separability, a 100% recycled paper (64 g / m ² ) having a further poor separability was used, and a rate of 6 g / min.
The paper was conveyed at zero speed. Other conditions are the same as in the above example. Regarding the paper ejection property, thick paper (200 g /
m ² ) The paper was passed and the delivery of the paper to the paper discharge roller was evaluated.

[0038]

[Table 2]

Evaluation of paper dischargeability…: paper can be discharged ×: not entering the paper discharge roller When θ <7 / 36π, the separation effect is poor because the effect of separation by paper strain is small, and when θ> π / 3 , Ie Φ
When> 11π / 36, the transportability of the thick paper deteriorates.

From the above results, when θ-Φ ≦ π / 36Φ ≦ 11π / 367 / 36π ≦ θ ≦ π / 3, both the separating property and the transporting property are good.

Further, in this configuration, the generated magnetic flux effectively heats the fixing roller 1 over a wide range, and the maximum heat generation area of the fixing roller 1 is arranged near the nip portion and upstream thereof, thereby generating the heat energy. Can be efficiently supplied to the recording material P. In the present embodiment, the arrangement of the T-shaped core has been described. However, the present invention is not limited to this configuration, and a similar effect can be obtained in a configuration using a core having another shape as shown in FIG.

(Second Embodiment) The operation and effect when the image heating apparatus of the present embodiment is used as a fixing device of a four-color image forming apparatus will be described together with the operation of the image forming apparatus.

FIG. 7 is a sectional view of an electrophotographic color printer using the present invention. Reference numeral 1011 denotes a photoconductor drum formed of an organic photoconductor, and the surface of the photoconductor drum 1011 is uniformly charged by a charging device 1012. When a laser beam 1101 that is turned on / off by a laser optical box 1013 based on a signal from an image signal generator (not shown) is irradiated through a mirror 1102, the photosensitive drum 1011 is statically irradiated. An electrostatic latent image is formed.
The electrostatic latent image thus formed on the photoconductor drum 1011 is visualized by selectively attaching toner by the developing device 1014. The developing device 1014 includes yellow Y, magenta M, and cyan. It is composed of a C color developing device and a black developing device B, and visualizes one color at a time.
The toner image of each color is transferred to the intermediate transfer drum 1016.
And a color image is formed on the intermediate transfer drum 1016. This intermediate transfer drum 1016
Has a medium-resistance elastic layer and a high-resistance surface layer on a metal drum, and applies a bias potential to the metal drum to transfer a toner image by a potential difference from the photosensitive drum 1011. On the other hand, the recording material P sent out from a paper feed cassette (not shown) by a paper feed roller (not shown) is transferred to a transfer roller 1015 and an intermediate transfer member in synchronization with the formation of an electrostatic latent image on the photosensitive drum 1011. It is sent between the drum 1016. Then, the transfer roller 1015 transfers the toner image on the intermediate transfer drum 1016 onto the recording material P by supplying a charge having a polarity opposite to that of the toner from the back surface of the recording material P. Thus, the recording material P on which the unfixed toner image is placed is conveyed to the heat fixing device 1010, where the fixing device 1010
Then, heat and pressure are applied to the recording material P so that the recording material P is permanently fixed on the recording material P, and is discharged to a discharge tray (not shown). The toner and paper dust remaining on the photosensitive drum 1011 are removed by the cleaner 1017, and the intermediate transfer drum 1
The toner and paper dust remaining on the surface 016 are removed by the cleaner 1018, and the photosensitive drum 1011 repeats the process after charging.

In this image forming apparatus, the fixing device 1
A core that forms a closed magnetic path on the excitation coil and the fixing roller is disposed inside the reference numeral 010. For this reason, heat generation occurs in the circumferential direction of the fixing roller, and the magnetic flux generated by the exciting coil 3 sufficiently heats the fixing roller 1 from the upstream of the nip, so that the recording material P is gradually heated and enters the nip.
After satisfactorily fixed in the nip portion where the heat generation peak occurs, the magnetic flux is rapidly weakened downstream of the nip, so that the magnetic flux is rapidly cooled at the nip outlet and separated easily. The separation claw is arranged at a position facing the core with respect to the fixing roller.

The fixing roller 1 of this embodiment will be described in detail with reference to FIG.

FIG. 8 shows an elastic layer 103 provided between a release layer 102 made of fluororesin and a 0.5 mm thick metal core (heat generating layer) 104 made of iron, which is used for fixing color toner. Will be As the heat generating layer 104, besides iron, 10 ^-5 to 1
A metal, a metal compound, or an organic conductor that is a good electrical conductor of 0 ^-10 Ω · m may be used. More preferably, a pure metal such as nickel or cobalt having high magnetic permeability and high ferromagnetism or a compound thereof is used. it can. And the elastic layer 10
The hardness of No. 3 is not more than 60 ° (JIS-A), and more preferably 45 °, because if the hardness is too high, unevenness of the recording material or toner layer cannot be completely followed and image gloss unevenness occurs.
(JIS-A) The following is preferred. Regarding the thermal conductivity of the elastic layer 103, 6 × 10 ⁻⁴ to 2 × 10 ⁻³ [cal / cm · s
ec · deg]. This is because the thermal conductivity λ is 6 × 10
If the value is smaller than ⁻⁴ [cal / cm · sec · deg], the thermal resistance is large, and the temperature rise in the surface layer of the fixing roller 1 becomes slow. Also, in the drawing, there is a separation claw, and when the elastic layer is 100 μm or more, the elastic layer is deformed in the nip portion, and the direction in which the transfer material passing through the nip is discharged is directed downward. The force with which the separation claw contacts the fixing roller can be further reduced. Also,
Considering the rate of temperature rise of the fixing roller 1, the elastic layer is 50
It is desirable that the thickness be 0 μm or less.

The release layer 102 is made of PFA, PTF
In addition to a fluororesin such as E and FEP, a material having good releasability and heat resistance such as a silicone resin, a silicone rubber, a fluororubber, and a silicone rubber can be selected. The thickness of the release layer 102 is preferably 20 to 100 μm. this is,
If the thickness of the release layer 102 is less than 20 μm, problems such as the formation of a portion having poor release properties due to coating unevenness of the coating film and insufficient durability occur.
If it exceeds 00 μm, the problem that heat conduction is deteriorated occurs, and particularly in the case of a resin-based release layer, the hardness becomes too high,
This is because the effect of the elastic layer 103 is lost.

As described above, according to the present invention, an image forming apparatus having higher separation properties and higher durability can be realized as compared with the case where a conventional image heating apparatus is used.

In the present embodiment, since the toner containing a low softening substance is used, the heat fixing device is not provided with an oil application mechanism for preventing offset.

In this embodiment, the four-color image forming apparatus has been described. However, the present invention may be applied to a monochrome or one-pass multi-color image forming apparatus. In this case, the elastic layer 103 can be omitted from the fixing roller 1.

In each of the above embodiments, the case where the image heating device of the present invention is used as a fixing device has been described. However, the image heating device of the present invention is not limited to this. Heating materials to improve surface properties (glossy etc.), hypothetical devices, and other sheets (sheets)
It can be widely used as an apparatus for heat-treating the above-mentioned material to be heated.

[0052]

According to the present invention, by appropriately arranging the separating means, the effect of cooling and separating can be obtained, and the material to be heated can be surely separated. Further, the image heating process can be stably performed without causing a jam or the like.

In particular, the contact pressure when the separating means is brought into contact with the rotary pressing member can be set low, and scratches on the rotary pressing member can be prevented.

As described above, it is possible to provide an image heating apparatus and an image forming apparatus which have solved the above-mentioned problems.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an image heating apparatus embodying the present invention.

FIG. 2 is a diagram of the heat generation principle of the induction heating method.

FIG. 3 is a schematic diagram showing lines of magnetic force generated from an exciting coil and guided by a core;

FIG. 4 is a chart showing a temperature distribution on a fixing roller surface near a nip;

FIG. 5 is a schematic diagram illustrating angles θ and Φ.

FIG. 6 is a schematic view showing another core form.

FIG. 7 is a schematic sectional view of an image forming apparatus according to a second embodiment of the present invention;

FIG. 8 is a schematic sectional view of an image heating apparatus embodying a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller (rotating heating member) 2 Pressing roller (rotating pressing member) 3 Excitation coil 4 High permeability core 5 Holder 6 Temperature sensor 7 Transport guide 8 Toner image 10 Separation claw 11 Photoconductor drum 14 Hollow core metal 15 Elasticity Layer 16 Excitation circuit 20 Inlet guide 21 Lower discharge guide 22 Upper discharge guide 23 Upper discharge roller 24 Lower discharge roller 102 Release layer 103 Elastic layer 104 Core metal 401, 402 Core 1010 Heat fixing device 1011 Photoconductor drum 1012 Charge Apparatus 1013 Laser optical box 1014 Developing device 1015 Transfer roller 1016 Intermediate transfer drum 1017, 1018 Cleaner 1102 Mirror P Recording material (heated material / transfer material)

Continued on front page F-term (reference) 2H033 AA25 BA27 BB18 BE06 3K059 AA08 AB00 AB19 AB20 AB23 AB28 AC10 AC73 AD15 AD34 CD44 CD66 CD75 CD77

Claims (7)

[Claims] A rotating heating member, a magnetic flux generating means disposed in the rotating heating member, generating a magnetic flux to form a closed magnetic path between the rotating heating member, and inducing heat generation in the rotating heating member; A rotary pressing member that presses against the rotary heating member to form a pressure contact portion, and a heated member that is disposed in contact with or close to the rotary heating member at a position downstream of the pressing nip portion in the rotation direction of the rotary pressing member. An image heating apparatus having a member separating means for heating an image on the material to be heated by introducing the material to be heated into the press-contact portion and nipping and transporting the material, in a cross section orthogonal to a rotation axis of the rotary heating member. And a line connecting the center of the rotary heating member and the center of the rotary heating member, where L is a line connecting the center of the rotary pressing member and the center of the rotary heating member. The angle θ [rad] formed with the line L is determined by the separation means The contact or proximity position and the line connecting the centers of rotation heating member with respect to the angle [Phi [rad] which forms between the line L, an image heating apparatus which is a θ-Φ ≦ π / 36. 2. A rotary pressing member, a rotary heating member for nipping and transporting a material to be heated in a press contact portion with the rotary pressing member, and abutting on or close to and close to the rotary heating member. Separating means for separating the material to be heated, wherein at least one excitation is located on the opposite side of the material to be heated with the rotary heating member interposed therebetween and generates an alternating magnetic field for generating an eddy current. And a high permeability member that guides the magnetic flux generated by the exciting coil in the circumferential direction of the rotary heating member to form a substantially closed magnetic path. A line L connecting the rotary pressing member and the center of the rotary heating member is provided. And the angle θ [rad] formed by the main magnetic field line, which is emitted in the direction of the rotary heating member in the vicinity of the press contact portion by the high magnetic permeability member and is the most downstream in the rotational direction of the rotary heating member, is separated from the line L. Abutment or proximity position of means and rotation To the angle [Phi [rad] which forms with the line connecting the center of the heating member, an image heating apparatus which is a θ-Φ ≦ π / 36. 3. The angle θ [rad] is 7 / 36π ≦ θ.
The image heating apparatus according to claim 1, wherein ≦ π / 3. 4. The angle Φ [rad] is Φ ≦ 11π / 3.
The image heating apparatus according to claim 1, wherein 5. The rotary heating member according to claim 1, wherein the heat generating portion is a conductive hollow pipe, and has a release layer on a surface of the rotary heating member. An image heating device according to claim 1. 6. The image heating apparatus according to claim 1, wherein the separation unit is a separation claw that contacts a rotary heating member. 7. The image heating apparatus according to claim 1, wherein a heat-softening colored powder image is formed on a recording material, and the recording material carrying the powder image is used as a material to be heated. An image forming apparatus, wherein an image is formed by fixing the powder image as a permanent image on the recording material by passing the powder image through an apparatus.