JP2001154518A - Heating device, image heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive heating device provided with high performances such as being capable of lowering power consumption, shortening waiting time, lowering driving torque, being used for full color toner images, improving durability and not generating slippage, fixing defects, gloss irregularities and offsets. SOLUTION: This heating device is provided with heating rotating bodies 6 and 7, a slide supporting member 3 for supporting the inner surface side of the heating rotating bodies on a slide surface through a lubricant 9 and a pressurizing rotating body 2 for clamping the heating rotating bodies with the slide supporting member and forming a nip part N, a material to be heated is clamped and carried by the nip part and the material to be heated is heated by heat from the heating rotating bodies. The heating rotating body is a cylindrical film for which the two of a first cylindrical film 6 on an inner side and a second cylindrical film 7 on an outer side are piled up and the length L1 in a longitudinal direction of the first cylindrical film 6 and the length L2 in the longitudinal direction of the second cylindrical film 7 satisfies L1>L2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heating device, an image heating device, and an image forming device.

More specifically, the heating rotator, a sliding support member for supporting an inner surface side of the heating rotator on a sliding surface via a lubricant, and the heating rotator between the sliding support member A pressing rotator that forms a nip portion with the nip portion interposed therebetween. The heating rotator and the pressing rotator of the nip portion sandwich and convey the material to be heated and receive heat by the heat from the heating rotator. The present invention relates to a heating device for heating a heating material, an image heating device for heating an image on a recording material, and an image forming apparatus including the heating device or the image heating device.

[0003] The present invention also relates to a heating device of an electromagnetic (magnetic) induction heating type, an image heating device, and an image forming apparatus provided with the heating device as an image heating device such as an image fixing device.

[0004]

2. Description of the Related Art For convenience, an image heating and fixing apparatus in an image forming apparatus such as an electrophotographic copying machine, a printer, and a facsimile will be described as an example.

[0005] The image heating and fixing device in the image forming apparatus uses an appropriate image forming process such as electrophotography, electrostatic recording, or magnetic recording in the image forming section of the image forming apparatus.
A heat fixing process is performed by using a toner (developing agent) made of a heat-meltable resin or the like to form a toner image formed on the surface of the recording material by a direct method or an indirect (transfer) method as a permanently fixed image on the surface of the recording material. It is a device to do.

Conventionally, as such an image heating and fixing apparatus, there are various systems such as a heat roller system, a film heating system, and an electromagnetic induction heating system.

A. Heat roller system This consists of a rotating roller pair consisting of a fixing roller (heat roller), which has a built-in heat source such as a halogen lamp and is heated and adjusted to a predetermined fixing temperature, and a pressure roller, and a pressure nip portion of the roller pair. An apparatus for heating and fixing an unfixed toner image to the surface of a recording material by introducing a recording material on which an unfixed toner image is formed and carried as a material to be heated (fixing nip portion), and nipping and conveying the recording material. .

However, this apparatus has problems such as a large heat capacity of the fixing roller, a large amount of electric power required for heating, and a long wait time (a waiting time from when the apparatus is turned on until a print output is enabled). .

In the case of a fixing device for a full-color image apparatus, since a capability of sufficiently heating and melting a maximum of four toner layers is required, the fixing roller has a core metal having a high heat capacity, and a toner layer having a high heat capacity. A rubber elastic material is provided on the outer periphery of the cored bar so as to wrap and melt uniformly, and the toner image is heated through the rubber elastic layer.

As described above, in the case of an apparatus using a fixing roller having a particularly large heat capacity, a delay occurs between the temperature control of the fixing roller and the temperature rise of the roller surface. Had occurred.

B. Film heating system This has a heating body and a film in which one surface slides with the heating body and the other surface moves in contact with the recording material, and heat of the heating body is recorded through the film. It is an apparatus for applying an unfixed toner image to a recording material by heating and fixing it on the surface of the recording material (Japanese Patent Application Laid-Open No. 63-313182, Japanese Patent Application Laid-Open No. 2-15
No. 7878, JP-A-4-44075-44083,
204980-204984, etc.).

Such a film heating type apparatus can use a low-heat-capacity ceramic heater or the like as a heating element and a heat-resistant, low-heat-capacity low-heat-capacity film as a heating roller using a fixing roller having a large heat capacity. Compared to the system of the system, there are advantages such as power saving and shortening of wait time in the pitching, quick start property, and suppression of temperature rise in the machine.

C. Electromagnetic induction heating method In this method, an electromagnetic induction heating element is used as a heating element, and a magnetic field is applied to the electromagnetic induction heating element by a magnetic field generating means, so that a toner image is covered with Joule heat based on an eddy current generated in the electromagnetic induction heating element. This is an apparatus for performing a heat fixing process on a recording material surface as a heating material.

Japanese Patent Publication No. 5-9027 discloses a heat roller type device for heating a ferromagnetic fixing roller by electromagnetic induction heating. The heat generating position can be made closer to the fixing nip portion. It realizes a more efficient fixing process than a heat roller type device used as a heat source.

[0015]

However, the apparatus disclosed in Japanese Patent Publication No. 5-9027 described above requires a large amount of electric power to raise the temperature of the fixing nip because the heat capacity of the fixing roller is large. There was a problem.

Japanese Unexamined Patent Publication (Kokai) No. 4-166966 discloses a fixing device of an electromagnetic induction heating system using a film-shaped fixing roller having a reduced heat capacity. However, it is common to use a good conductor made of metal for the film-like fixing roller, and as described in the film heating method described above, the film is driven by the frictional force at the nip by driving the pressure roller. The rotation method has a problem that the driving torque at the time of starting is large.

As a method for solving this problem, there is a method in which grease as a lubricant is applied to the nip to reduce the frictional force in the nip and reduce the driving torque at the time of startup. In addition, there is a problem in durability that the metal film is deteriorated due to mixing of shaving powder.

A method of mounting a heat-resistant resin film such as a polyimide resin film in a metal film for the purpose of preventing the deterioration of grease is conceivable. However, a lubricant (grease) applied to the nip portion is formed inside the heat-resistant resin film. It goes around between the metal film and the heat-resistant resin film from the end,
Partial rubbing (slip) occurs between the metal film and the heat-resistant resin film, causing problems such as uneven wear of the heat-resistant resin film and generation of chattering noise.

Therefore, it has low power consumption, can reduce the wait time, can reduce the driving torque, can be used for full-color toner images, has high durability, and has poor slip and fixation.・ Glossy unevenness ・
There is a demand for an image forming apparatus including an inexpensive fixing device having high performance such as no occurrence of offset.

The present invention provides a heating apparatus, an image heating apparatus, and an image forming apparatus which can meet such a demand.

[0021]

According to the present invention, there is provided a heating device, an image heating device and an image forming device having the following constitutions.

(1) A heating rotator, a sliding support member for supporting an inner surface of the heating rotator on a sliding surface via a lubricant,
A pressurizing rotator that forms a nip portion with the heating rotator interposed between the sliding support member and a heating target material between the heating rotator and the pressurizing rotator of the nip portion. A heating device for heating the material to be heated by the heat from the heating rotator, wherein the heating rotator has an inner first cylindrical film and an outer second cylindrical film that overlap each other. L1> L2 when the length of the first cylindrical film in the longitudinal direction is L1 and the length of the second cylindrical film in the longitudinal direction is L2. Heating equipment.

(2) The heating device according to (1), wherein L1>Lk> L2, where Lk is the length in the longitudinal direction of the pressure rotating body.

(3) The heating device according to (1) or (2), wherein the second cylindrical film is an induction heating element that generates electromagnetic induction by the action of magnetic flux generated by magnetic flux generating means.

(4) The heating device according to any one of (1) to (3), wherein the first cylindrical film is a heat-resistant resin film.

(5) The sliding support member has a central convex shape with respect to the rotation axis direction of the first and second cylindrical films, according to any one of (1) to (4). A heating device as described.

(6) The heating device according to any one of (1) to (5), wherein the first and second cylindrical films are driven to rotate at the nip portion by the pressure rotating body. apparatus.

(7) An image heating apparatus for heating an image on a recording material, wherein the image heating means is the heating apparatus according to any one of (1) to (6). Image heating device.

(8) An image heating apparatus for fixing a toner image by heating and pressurizing a recording material carrying an unfixed toner image, wherein the means for heating and pressurizing the recording material is as described in (1) to (6). An image heating device, which is the heating device according to any one of the above.

(9) An image forming apparatus for forming a toner image on a recording material, and passing the recording material carrying the toner image through a fixing device to convert the toner image into a permanent image. An image forming apparatus using the heating device according to any one of (1) to (6) as an apparatus.

<Operation> a) A heating rotator composed of two cylindrical films, an inner first cylindrical film and an outer second cylindrical film, is superposed on the inner surface of the inner first cylindrical film. Since it is supported on the sliding surface of the sliding support member via the lubricant (grease), the frictional force at the nip portion is reduced, and the driving torque can be reduced.

B) The first cylindrical film, which constitutes the heating rotator, is made of a heat-resistant resin film, and the second cylindrical film is made of an induction heating element which generates electromagnetic induction by the action of magnetic flux generated by magnetic flux generating means. This prevents thermal deterioration of the lubricant and deterioration of the metal film on the side of the second cylindrical film, which is the induction heating element, due to mixing of shavings.

C) The relationship between the longitudinal length L1 of the inner first cylindrical film and the longitudinal length L2 of the outer second cylindrical film that constitute the heating rotator is set to L1> L2. By doing so, the lubricant interposed between the inner surface of the inner first cylindrical film and the sliding surface of the sliding support member becomes the first lubricant.
The wraparound between the first cylindrical film and the second cylindrical film from the end inside the cylindrical film is prevented. Therefore, when the lubricant goes around between the first cylindrical film and the second cylindrical film, a partial rubbing (slip) occurs between the two films, causing uneven wear and chattering of the first cylindrical film. Problems such as generation of sound are eliminated.

Thus, low power consumption, shortening of the wait time, reduction of the driving torque, use for full-color toner images,
It is possible to realize an inexpensive heating device, an image heating device, and an image forming apparatus including the device, which are highly durable and have high performance such as no occurrence of slip, fixing failure, gloss unevenness, and offset.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (FIGS. 1 to 8) (1) Example of Image Forming Apparatus FIG. 1 is a diagram showing a schematic configuration of an example of an image forming apparatus.
The image forming apparatus of this example is an electrophotographic full-color printer.

Numeral 11 denotes an electrophotographic photosensitive drum (image bearing member) made of an organic photosensitive member, which is rotated at a predetermined process speed (peripheral speed) in a counterclockwise direction indicated by an arrow A.

The photosensitive drum 11 undergoes a uniform charging process of a predetermined polarity and potential by a charging device 12 such as a charging roller during the rotation process.

Next, the charged surface is subjected to a scanning exposure process of target image information by a laser beam LB output from a laser optical box (laser scanner) 13. The laser optical box 13 outputs laser light LB modulated (on / off) according to a time-series electric digital pixel signal of target image information from an image signal generator such as a computer (not shown), and outputs the laser light LB to the surface of the photosensitive drum 11. Are scanned and exposed, and an electrostatic latent image corresponding to the target image information scanned and exposed on the surface of the photosensitive drum 11 is formed by the scanning exposure. A mirror 13a reflects the output laser light from the laser optical box 13 to the exposure position of the photosensitive drum 11.

In the case of forming a full-color image, scanning exposure and latent image formation are performed on a first color-separated component image of a target full-color image, for example, a yellow component image. The toner is developed as a yellow toner image by the operation of the yellow developing device 14Y.

The yellow toner image is transferred to the photosensitive drum 11
The image is transferred onto the surface of the intermediate transfer drum 16 at a primary transfer portion T1 which is a contact portion (or a close portion) between the intermediate transfer drum 16 and the intermediate transfer drum 16.

After the transfer of the toner image to the surface of the intermediate transfer drum 16, the surface of the photosensitive drum 11 is cleaned by the cleaner 17 by removing the adhered residue such as untransferred toner.

The process cycle of charging, scanning exposure, development, primary transfer, and cleaning as described above is performed for the second (for example, magenta component image, magenta developing unit 14M is activated) and the third (for example, cyan) of the target full-color image. The color separation component image is sequentially executed for each of the component image, the cyan developing device 14C) and the fourth (for example, the black component image, the black developing device 14Bk), and a yellow toner image and a magenta toner are formed on the intermediate transfer drum 16 surface. An image, a cyan toner image, and a black toner image are successively transferred in a superimposed manner to form a color image corresponding to a target full-color image.

The intermediate transfer drum 16 has a medium-resistance elastic layer and a high-resistance surface layer on a metal drum, and is brought into contact with or close to the photosensitive drum 11 at substantially the same peripheral speed as the photosensitive drum 11. Rotation is performed in the clockwise direction of arrow B to apply a bias potential to the metal drum and transfer the toner image on the photosensitive drum 11 to the surface of the intermediate transfer drum 16 with a potential difference from the photosensitive drum 11.

The color toner image synthesized on the surface of the intermediate transfer drum 16 is transferred to the secondary transfer portion T2 at the secondary transfer portion T2 which is a contact nip portion between the intermediate transfer drum 16 and the transfer roller 15. Is transferred onto a surface of a recording material (transfer material) P sent at a predetermined timing from a paper feeding unit (not shown).

The transfer roller 15 supplies charges having a polarity opposite to that of the toner from the back surface of the recording material P to sequentially transfer the combined color toner images from the surface of the intermediate transfer drum 16 to the recording material P in a batch.

The recording material P that has passed through the secondary transfer portion T2 is separated from the surface of the intermediate transfer drum 16 and introduced into the image heating and fixing device (image heating device) 10, where the unfixed toner image is heated and fixed. In response to this, the sheet is discharged as a color image formed product on a discharge tray (not shown) outside the apparatus.

The image heating and fixing device 10 is an electromagnetic induction heating type device according to the present invention. The fixing device 10 will be described in detail in the following section (2).

After the transfer of the color toner image onto the recording material P, the intermediate transfer drum 16 is cleaned by the cleaner 18 after removing the residual toner such as untransferred toner and paper dust.

The cleaner 18 is normally kept in a non-contact state with the intermediate transfer drum 16, and during the secondary transfer of the color toner image from the intermediate transfer drum 16 to the recording material P, the intermediate transfer drum 16 is maintained. Is kept in contact.

The transfer roller 15 is always kept in a non-contact state with the intermediate transfer drum 16, and during the secondary transfer of the color toner image from the intermediate transfer drum 16 to the recording material P, the intermediate transfer member It is held in contact with the drum 16.

Information (paper size, paper thickness, special paper information, etc.) on the recording material P can be attached to the target image information from an image signal generator (computer) not shown.

Based on this information, the image forming apparatus selects a suitable recording material P in a paper feeding unit (not shown) and performs the above-described paper feeding operation, and stores information on the recording material in a storage device in the apparatus. 101 (FIG. 5) and used as parameters for controlling the image heating and fixing apparatus 10.

(2) Image Heat Fixing Apparatus 10 FIG. 2 is a schematic front view of the image heating fixing apparatus 10, FIG. 3 is a longitudinal sectional view, and FIG. 4 is an enlarged transverse section taken along line (4)-(4) in FIG. FIG. 5 is a perspective view of the magnetic flux generating means.

The fixing device 10 includes the heating assembly 1
And a pressure roller 2 as a pressure rotating body.

The heating assembly 1 comprises a cylindrical film guide member 3, an excitation coil 4 as a magnetic flux generating means disposed inside the film guide member 3, and a magnetic core (magnetic member, high permeability member).
5. A cylindrical heat-resistant resin film 6 (first cylindrical film) loosely fitted to the film guide member 3, and a cylindrical fixing film 7 as a cylindrical induction heating element loosely fitted to the heat-resistant resin film 6. (Second cylindrical film),
The film guide member 3 includes end rings (flange members) 8.8 attached to both end portions of the film guide member 3, respectively.

In the above description, the inner and outer superposed bodies 6.7 of the cylindrical heat-resistant resin film 6 and the cylindrical fixing film 7 as the induction heating element are the heating rotator.

The film guide member 3 is a sliding support member for supporting the heating rotators 6 and 7 on a sliding surface via a lubricant (grease). Exciting coil 4 that is an insulating and heat-resistant material member that does not hinder the passage of magnetic flux and is a magnetic flux generating means.
And the magnetic core 5, and also serves to secure the rotation stability of the heating rotator by guiding the inner surfaces of the heat-resistant resin films 6 of the heating rotators 6 and 7.

The pressure roller 2 is an elastic roller composed of a metal core 2a and a silicone rubber layer 2b covering the outer periphery of the metal core. The pressure roller 2 is disposed between left and right side plates of a device chassis (not shown) so that both ends of a cored bar 2a are rotatably supported via bearings 31.

The heating assembly 1 is also disposed in parallel with the pressure roller 2 above the pressure roller 2 between the left and right side plates of the apparatus chassis, and the rigid stay for pressure 32 is inserted into the space inside the film guide member 3. Then, the lower surface thereof is received on the upper surface of the magnetic core 5, and the pressing springs 34, 34 are respectively provided between both end portions and the spring receiving members 33, 33 on the device chassis side.
Has been contracted.

As a result, a pressing force acts on the film guide member 3 via the pressurizing rigid stay 32 and the magnetic core 5 so that the lower surface of the film guide member 3 and the upper surface of the pressure roller 2 are heat-resistant resin which is a heating rotator. The film 6 and the fixing film 7 are pressed against each other with a predetermined pressing force to form a fixing nip portion N having a predetermined width.

Grease 9 as a lubricant is applied to the surface of the cylindrical film guide member 3 in advance, and the grease 9 is provided between the lower surface of the film guide member 3 and the inner surface of the heat-resistant resin film 6 at the fixing nip N. 9 intervenes. In this example, Molycoat HP300 grease manufactured by Dow Corning was used as grease 9 as a lubricant.

Reference numeral 35 denotes a drive gear fixed to one end of the cored bar 2a of the pressure roller 2, and when a rotational force is transmitted from the drive means M to the drive gear G, the pressure roller 2 is turned into an arrow in FIG. a is driven to rotate counterclockwise (a pressure roller driving type). A fixing nip N is formed between the roller 2 and the outer surface of the fixing film 7 by the rotational driving of the pressure roller 2.
The rotational force acts on the fixing film 7 due to the frictional force at
The fixing film 7 rotates around the film guide member 3 in the clockwise direction as indicated by the arrow b, while also rotating the heat-resistant resin film 6 inside.

The end rings 8.8 mounted on both ends of the film guide member 3 receive the ends of the heat-resistant resin film 6 when the heat-resistant resin film 6 and the fixing film 7, which are the heating rotator, rotate, and heat them. It serves to regulate the movement of the rotating bodies 6 and 7 along the length of the film guide member 3.

In this embodiment, the outer diameters of both ends of the film guide member 3 are slightly reduced to provide an annular step, and the end rings 8.8 are rotatably fitted to the respective annular steps. The stopper ring 8a restricts the movement in the thrust direction to fix the left and right positions so that the stopper ring cannot come off.

This end ring 8.8 is connected to the heating rotator 6.7
During rotation, the end portion of the heat-resistant resin film 6 is received by the inner surface of the ring, and rotates along with the heat-resistant resin film 6 to protect the film end surface, and at the same time, the grease between the film guide member 3 and the heat-resistant resin film 6. It also plays a role in preventing the emission of Nine.

The exciting coil 4 of the magnetic flux generating means is composed of an exciting circuit 4
0 (FIG. 5), an alternating magnetic flux is generated by the alternating current, and the alternating magnetic flux is guided to the magnetic core 5 to generate an eddy current in an electromagnetic induction heating layer of the fixing film 7 described later. The eddy current generated in the electromagnetic induction heating layer of the fixing film 7 generates Joule heat due to the specific resistance of the electromagnetic induction heating layer.
That is, by supplying an alternating current to the exciting coil 4, the fixing film 7 enters an electromagnetically induced heating state.

The temperature of the fixing nip portion N is controlled to a predetermined fixing temperature by controlling the alternating current supplied from the exciting circuit 40 to the exciting coil 4 by a control circuit 100 including a temperature detecting means (not shown). You.

Thus, the pressure roller 2 is driven to rotate,
Heat-resistant resin film 6 and fixing film 7 as heating rotator
Are rotated, and an alternating current is supplied to the exciting coil 4 so that the temperature of the fixing nip N is raised to a predetermined value and the temperature is adjusted. During this time, the recording material P carrying the unfixed toner image t as the material to be heated is introduced,
The recording material P is in close contact with the outer surface of the fixing film 7 and passes through the fixing nip portion N together with the fixing film 7, and in the process of passing through the fixing nip portion, heat is generated by the fixing film 7 heated by electromagnetic induction. The recording material P and the unfixed toner image t are heated, and the toner image is heated and fixed.

The recording material P that has passed through the fixing nip N is separated from the outer surface of the fixing film 7 at the exit side of the fixing nip N and conveyed.

(A) Magnetic Flux Generating Means 4 and 5 The exciting coil 4 of the magnetic flux generating means of this embodiment uses an insulated coated conductor, and has a horizontally long boat shape whose outer shape substantially corresponds to the inner surface of the cylindrical film guide member 3. The inner surface of the cylindrical film guide member 3 is inserted into the cylindrical film guide member 3 by receiving an outer surface on a substantially lower half surface thereof.

The exciting coil 4 must generate an alternating magnetic flux sufficient for heating. For this purpose, it is necessary to reduce the resistance component and increase the inductance component.

In this embodiment, the exciting coil 4 is formed by winding a winding 12 times around the fixing nip portion N using a high-frequency φ1 insulating-coated conductor in which fine wires are bundled as a core wire.

An excitation circuit 40 is connected to the excitation coil 4. The excitation circuit 40 can supply an alternating current of 50 KHz to the excitation coil 4.

The magnetic core 5 is a horizontally long ferrite core, and is located at the approximate center of the horizontally long exciting coil 4 and is supported by the cylindrical film guide member 3. The magnetic core 5 has a role to efficiently guide the alternating magnetic flux generated from the exciting coil 4 to the fixing film 6.

(B) Heating Rotators 6 and 7 As described above, the heating rotators are a cylindrical heat-resistant resin film (first cylindrical film) 6 and a fixing film 7 (second cylindrical film) as a cylindrical induction heating element. Inside and outside 2 with cylindrical film)
It is a superposition of two.

. Heat resistant resin film 6 Cylindrical heat resistant resin film 6 as first cylindrical film
Has an inner diameter slightly larger than the outer diameter of the cylindrical film guide member 3 and an outer diameter slightly smaller than the inner diameter of the fixing film 7 as the second cylindrical film. Fit outside.

The heat-resistant resin film 6 is made of a fluororesin, a polyimide resin, a polyamide resin, a polyamideimide resin,
PEEK resin, PES resin, PPS resin, PFA resin,
A heat-resistant resin such as PTFE resin and FEP resin is preferable.

The thickness is preferably from 10 to 1000 μm. If the thickness is less than 10 μm, the durability will be insufficient. If it exceeds 1000 μm, the distance from the magnetic core 5 to the heat generating layer of the fixing film 7 increases, and the magnetic flux does not sufficiently reach the heat generating layer.

When the heat-resistant resin film 6 is provided, the temperature of the exciting coil 4 and the magnetic core 5 due to the heat generated in the heat generating layer of the fixing film 7 can be prevented, so that stable heating can be performed.

In this example, the heat-resistant resin film 6, which is the first cylindrical film, is made of polyimide resin and has a thickness of 50 μm.
m single-layer cylindrical film was used.

[0081] Fixing Film 7 The fixing film 7 as the second cylindrical film is a cylindrical member including an electromagnetic induction heating layer, and has an inner diameter slightly larger than the outer diameter of the heat-resistant resin film 6 as the first cylindrical film. Yes, it is loosely fitted to the heat-resistant resin film 6.

FIG. 6 is a schematic diagram of the layer structure of the fixing film 7. The fixing film 7 of the present embodiment includes an electromagnetic induction heating layer 7a on the inner side (on the heat resistant resin film 6 side) and an elastic layer 7 on the outer side.
b, and a release layer outside thereof (surface layer; side of pressure roller 2)
7c is a three-layer composite layer structure.

The heat of the electromagnetic induction heating layer 7a is transferred to the fixing nip N
Is transferred via the elastic layer 7b and the release layer 7c to the recording material P conveyed to the recording material P and the toner image t on the recording material.
Heat.

The heat generating layer 7a is a material layer having an electromagnetic induction heat generating property in which Joule heat is generated by an eddy current due to the action of an alternating magnetic flux, and is a metal such as nickel, which is a good electric conductor of 10 ⁻⁵ to 10 ⁻¹⁰ Ω · cm. Any compound or organic conductor may be used, and more preferably, a pure metal such as iron or cobalt having high magnetic permeability and exhibiting ferromagnetism or a compound thereof can be used.

When the thickness of the heat generating layer 7a is reduced, a sufficient magnetic path cannot be secured, and magnetic flux may leak to the outside, and the heat generated by the heat generating element itself may be reduced. The time required tends to be longer. Therefore, the thickness has an appropriate value depending on the specific heat, density, magnetic permeability, and resistivity of the material used for the heat generating layer 7a.
Actually, when operated as a heat fixing device, 10 to 10
In the thickness range of 100 μm, a temperature rising rate of 3 deg / sec or more as the surface temperature of the fixing film 7 could be obtained.

The elastic layer 7b is a rubber layer made of silicone rubber or the like. In the present embodiment, the elastic layer 7b is provided to improve the fixation of a color toner image composed of a maximum of four toner layers. It acts to envelop and melt evenly due to the elasticity of the material.

If the hardness of the elastic layer 7b is too high, the elastic layer 7b cannot follow irregularities of the recording material or the toner layer, resulting in uneven image gloss. Therefore, the hardness of the elastic layer 6b is 6
0 ° (JIS-A; JIS-K (using A type measuring device)) or less, more preferably 45 ° or less.

Regarding the thermal conductivity λ of the elastic layer 7b,
52 × 10 ^{-1 to} 8.4 × 10 ^-1 W / m · ° C. (6 × 10 ^-4
２2 × 10 ⁻³ cal / cm · sec · deg. ) Is good. Thermal conductivity λ is 2.52 × 10 ⁻¹¹ W / m · ° C. (6 ×
10 ⁻⁴ cal / cm · sec · deg. If it is smaller than ()), the thermal resistance is large and the rate of temperature rise on the surface layer of the fixing film becomes slow.

The thickness of the elastic layer 7b is 100 to 300 μm.
When it is smaller than 100 μm, spot-like gloss unevenness is apt to occur when the ratio of a base image is large as in a color image forming apparatus, and when it exceeds 300 μm, a large thermal gradient is generated between the surface and the heat generating layer 6 a. And the thermal degradation of the elastic layer is likely to occur.

The release layer 7c is for preventing toner from adhering to the surface of the fixing film, and is made of a releasable and heat-resistant material such as fluororesin such as PFA, PTFE and FEP, silicone resin, silicone rubber, fluororubber and silicone rubber. A good material can be selected.

The thickness of the release layer 6c is preferably from 20 to 100 μm. If the thickness is less than 20 μm, there arises a problem that uneven coating of the coating film causes poor releasability or insufficient durability. In addition, if the release layer exceeds 100 μm, there is a problem that heat conduction is deteriorated. In particular, in the case of a resin-based release layer, the hardness becomes too high, and the effect of the elastic layer 7b is lost.

The fixing film 7 used in this example is composed of a heating layer 7a of nickel having a thickness of 50 μm, an elastic layer 7b of silicone rubber having a thickness of 300 μm, and a release layer 7c of fluorocarbon resin having a thickness of 30 μm. It is a layer composite layer film.

[0093] Heat resistant resin film 6 and fixing film 7
In FIG. 2, L1 is the longitudinal length of the heat-resistant resin film 6 as the first cylindrical film, L2 is the longitudinal length of the fixing film 7 as the second cylindrical film,
Lk is the length in the longitudinal direction of the pressure roller 2 (the length of the elastic layer 2b in the longitudinal direction), which is a pressure rotating body.

With respect to the lengths L1 and L2 of the heat resistant resin film 6 and the fixing film 7, as shown in the model diagram of FIG. 7, the lengths L1 and L2 of the heat resistant resin film 6 and the fixing film 7 in the longitudinal direction are the same. At the time, that is, when the end surfaces of the heat-resistant resin film 6 and the fixing film 7 coincide with each other, the grease 9 having increased fluidity due to heat moves from the inside of the heat-resistant resin film 6 to the end ring 8 side, and Fixing film 7
Wraps around the middle of When the length L1 of the heat-resistant resin film 6 in the longitudinal direction is shorter than the length L2 of the fixing film 7 in the longitudinal direction (L1 <L2), the grease 9 is located between the heat-resistant resin film 6 and the fixing film 7. Needless to say, it goes around.

In this embodiment, as shown in the model diagram of FIG. 8, the heat-resistant resin film 6 which is the first cylindrical film is used.
The length L1 in the longitudinal direction is longer than the length L2 in the longitudinal direction of the fixing film 7 as the second cylindrical film, and L1> L2.

By adopting such a configuration, the grease 9 inside the heat-resistant resin film 6 does not wrap around from the end to the surface of the heat-resistant resin film 6, that is, between the fixing film 7 and the heat-resistant resin film 6. 9 can be held inside the heat-resistant resin film 6 while maintaining the ability of the lubricant.

When the length difference L between the ends of the heat-resistant resin film 6 and the fixing film 7 (the distance between the ends of the heat-resistant resin film protruding from the end of the fixing film and the total length) is short, the target life is shortened. There is a high risk that the grease 9 may flow into the inside of the fixing film 7 from the end of the heat-resistant resin film 6 before reaching. Further, when the length is increased, the width of the fixing device is increased, and the size and weight of the entire device are increased, which leads to an increase in cost.

Therefore, in this example, the length difference L between the ends was 20 mm longer than the fixing film 7 in consideration of the deviation of the fixing film 7 (L = 20 mm).

In the case of Embodiment 1 where L = 20 mm,
In each case of L = -1 mm as Comparative Example 1 and L = 0 mm as Comparative Example 2, the state of the grease 9 wrapping between the heat-resistant resin film 6 and the fixing film 7 in each case was verified. Table 1 shows the results.

[0100]

[Table 1]

As shown in Table 1, when L = -1 mm, it is clear that grease wraps around, and a slip occurs between the heat-resistant resin film 6 and the fixing film 7.

Further, even when L = 0 mm, the grease wraps around as the number of prints increases, and a slip occurs between the heat-resistant resin film 6 and the fixing film 7.

By setting L = 20 mm, the grease 9 inside the heat-resistant resin film 6 is moved from the end to the heat-resistant resin film 6.
The grease 9 can be held inside the heat-resistant resin film 6 while maintaining the ability of the lubricant, without wrapping around the surface of the fixing film 7 and the heat-resistant resin film 6. Therefore, the driving torque can be reduced, and a durable image heat fixing device free from slipping can be provided.

<Embodiment 2> (FIG. 9) FIG. 9 is a schematic longitudinal sectional view of a heat fixing device according to Embodiment 2 of the present invention.

The apparatus of the present embodiment is different from the heating and fixing apparatus of Embodiment 1 in that the shape of the cylindrical film guide member 3 at the fixing nip portion is determined with respect to the rotation axis direction of the heating rotators 6 and 7 (the longitudinal direction of the guide member). It has a central convex shape. The other configuration of the apparatus is the same as that of the heat fixing apparatus according to the first embodiment, and thus the description thereof is omitted.

In this embodiment, since the heat-resistant resin film 6 and the fixing film 7, which are the heating rotator, hardly move toward the ends along the length of the film guide member 3 during rotation, the length L1 of the heat-resistant resin film 6 in the longitudinal direction is reduced. It is sufficient if the length of the fixing film 7 is slightly longer than the length L2 in the longitudinal direction of the fixing film 7, so that the dimensional difference L between the ends of the heat-resistant resin film 6 and the fixing film 7 can be reduced.

In this example, L = 1 mm was set.

In the case of Example 2 where L = 1 mm, the case where L = −1 mm as Comparative Example 3, and the case where L = −1 mm as Comparative Example 4.
= 0 mm, heat resistant resin film 6 in each case
The degree of the grease 9 wrapping around between the fixing film 7 and the fixing film 7 was verified. Table 2 shows the results.

[0109]

[Table 2]

As shown in Table 2, when L = -1.0 mm, grease wraps around as in the first embodiment. However, when L = 1 mm, no grease wraps around. Since the dimensional difference L between the ends can be made shorter than in the case of, the heat-resistant resin film 6 can be shortened and the device itself can be downsized.

In this manner, by forming the shape of the film guide member 3 at the fixing nip portion N at the center convex shape with respect to the rotation axis direction of the heating rotators 6 and 7, similarly to the first embodiment, the inside of the heat-resistant resin film 6 can be formed. The grease 9 is held inside the heat-resistant resin film while maintaining the ability of the lubricant without the grease 9 wrapping around the surface of the heat-resistant resin film 6, that is, between the heat-resistant resin film 6 and the fixing film 7 from the end. It is suitable for a smaller image forming apparatus in which no slip occurs.

<Embodiment 3> (FIGS. 10 and 11) FIG. 10 is a schematic front view of a heat fixing device according to Embodiment 3 of the present invention.
FIG. 11 is an enlarged structural model diagram of a main part.

The apparatus of this embodiment is different from the heat fixing apparatus of Embodiment 1 in that the length Lk in the longitudinal direction of the pressing roller 2 as the pressing rotator is changed to the first cylindrical shape of the heating rotators 6 and 7. Set to be shorter than the longitudinal length L1 of the heat-resistant resin film 6 as the film and longer than the longitudinal length L2 of the fixing film 7 as the second cylindrical film (L1>Lk> L2).
It was done. The other configuration of the apparatus is the same as that of the heat fixing apparatus according to the first embodiment, and thus the description thereof is omitted.

In this embodiment, since the heat-resistant resin film 6 can be directly driven by the pressure roller 2, the gripping force is more easily obtained than the release layer 7c of the fixing film 7, and the conveying force is improved.

Further, as shown in the enlarged schematic diagram of the main part of FIG. 11, the grease 9 between the cylindrical film guide member 3 and the heat-resistant resin film is discharged only up to the vicinity of the end ring 8 and the heat-resistant resin film 6 And the fixing film 7 does not go around.

By arranging the pressure roller 2, the heat-resistant resin film 6, and the fixing film 7 in this manner, the grease 9 inside the heat-resistant resin film 6 can be moved from the end to the heat-resistant resin film 6 similarly to the first embodiment. Grease is held inside the heat-resistant resin film while maintaining the ability of the lubricant without wrapping around the surface of the heat-resistant resin film 6 and the fixing film 7, so that a higher-speed image formation with no slip is generated. Suitable for equipment.

<Others> 1) In the embodiment, the example in which the information on the recording material is obtained from an external image signal generating device (computer or the like) is shown. However, a sensor such as a paper size detecting mechanism is provided in the device. The detected information can be stored in the storage device 101 (FIG. 5) and used.

Although the four-color image forming apparatus has been described, the present invention may be applied to a monochrome image forming apparatus. In this case, the elastic layer 7b can be omitted from the fixing film 7.

2) The heating rotators 6 and 7 are endless belt-shaped members which are stretched between two or more members and are driven to rotate by the pressing roller 2 or a driving means other than the pressing roller. There may be.

3) A roller made of a thin magnetic material can be used for the induction heating element. Also in this case, the excessive temperature rise of the non-sheet passing portion, which is likely to occur due to its thin thickness, can be remarkably improved by the effect of the present invention.

4) An apparatus in which the magnetic flux generating means composed of the exciting coil 4 and the like are arranged around the induction heating element such as the fixing film 7 may be used.

5) According to the present invention, a fixed ceramic heater or a fixed electromagnetic induction heating member is used as a heating element, and this heating element, a heating rotator sliding on the heating element, and a heating rotator interposed therebetween. A pressurizing rotating body that forms a nip with the heating body, and heats the heated material by heat from the heating body via the heating rotator while nipping and conveying the heated material in the nip. And the image heating apparatus.

6) The rotary pressure member 2 is not limited to a roller body,
Other types of members such as a rotating belt type may be used.

Further, the rotary pressurizing member 2 is provided with a suitable heating means so as to supply heat to the material to be heated from the rotary pressurizing member 2 side, so that the apparatus is configured to perform heating and temperature control. Can also.

7) The heating device of the present invention is not limited to the image heating and fixing device of the embodiment, but is an image heating device for heating a recording material carrying an image to improve the surface properties such as gloss. Image heating device, other heating and drying device for the material to be heated,
It can be widely used as a means / apparatus for heat-treating a material to be heated, such as a heating laminating apparatus.

[0126]

As described above, according to the present invention, it is possible to reduce the power consumption and the wait time.
An inexpensive heating device and image that can reduce the driving torque, can be used for full-color toner images, has high durability, and has high performance such as no occurrence of slip, fixing failure, gloss unevenness, and offset A heating device and an image forming apparatus including the heating device can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment.

FIG. 2 is a front model diagram of an image heating fixing device.

FIG. 3 is also a longitudinal sectional model view

FIG. 4 is an enlarged cross-sectional model diagram along the line (4)-(4) in FIG. 2;

FIG. 5 is a perspective view of a magnetic flux generating unit.

FIG. 6 is a schematic diagram of a layer structure of a fixing film (induction heating element film).

FIG. 7 is a schematic diagram of a main part for explaining the grease wrap around when the end surfaces of the heat-resistant resin film and the fixing film are aligned.

FIG. 8 is a model diagram of a main part in the case of the first embodiment.

FIG. 9 is a schematic longitudinal sectional view of an image heating and fixing apparatus according to a second embodiment.

FIG. 10 is a schematic front view of an image fixing device according to a third embodiment.

FIG. 11 is a model drawing of a main part.

[Explanation of symbols]

Reference numeral 10: heating fixing device, 1: heating assembly, 2
... pressure roller (pressure rotating body), 3 ... cylindrical film guide member (sliding support member), 4, 5 ... excitation coil and magnetic core (magnetic flux generating means), 6, 7 ..Heat-resistant resin film as first cylindrical film and fixing film (heating rotator) as second cylindrical film, 8...
End ring, 9: grease, L: distance that the heat-resistant resin film end projects from the fixing film end

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Takashi Nomura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hideo Nanataki 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-corporation F term (reference) 2H033 AA30 BA11 BA12 BA25 BE03 BE06 3K059 AB23 AC33 AD02 AD03

Claims (9)

[Claims] 1. A heating rotating body, a sliding support member for supporting an inner surface side of the heating rotating body on a sliding surface via a lubricant, and the heating rotating body is sandwiched between the sliding supporting member. A pressurizing rotator forming a nip portion at the nip portion, and holding and conveying the material to be heated between the heating rotator and the pressurizing rotator of the nip portion; A heating device, wherein the heating rotator is a cylindrical film in which two of an inner first cylindrical film and an outer second cylindrical film are overlapped with each other; When the length in the longitudinal direction is L1, and the length in the longitudinal direction of the second cylindrical film is L2, L1> L2. 2. The heating apparatus according to claim 1, wherein L1>Lk> L2, where Lk is the length in the longitudinal direction of the pressure rotating body. 3. The heating device according to claim 1, wherein the second cylindrical film is an induction heating element that generates electromagnetic induction by the action of the magnetic flux generated by the magnetic flux generating means. 4. The heating device according to claim 1, wherein the first cylindrical film is a heat-resistant resin film. 5. The heating device according to claim 1, wherein the sliding support member has a central convex shape with respect to a rotation axis direction of the first and second cylindrical films. apparatus. 6. The heating device according to claim 1, wherein the first and second cylindrical films are driven to rotate by the pressure rotating body at a nip portion. 7. An image heating apparatus for heating an image on a recording material, wherein the image heating means is the heating apparatus according to any one of claims 1 to 6. . 8. An image heating apparatus for fixing a toner image by heating and pressurizing a recording material carrying an unfixed toner image, wherein the means for heating and pressurizing the recording material is provided. An image heating device, which is the heating device according to any one of claims 1 to 3. 9. An image forming apparatus for forming a toner image on a recording material and passing the recording material carrying the toner image through a fixing device to convert the toner image into a permanent image, wherein the fixing device comprises: An image forming apparatus using the heating device according to any one of claims 1 to 6.