JPH10319753A - Heater, heating device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device image forming device and heater used for the device capable of operating at a higher speed, with saved power, in a shorter waiting time and with higher durability by providing a metal film and a heater with an heating element on the substrate face on the opposite side of the face sliding with the film. SOLUTION: A device has a heater 12 provided with a heater element 12b heating through the electrification of a substrate, a supporting member 13 to fix and supporting the heater 12 and a film 10 sliding with the heater 12 so that heat treatment can be given to a material P to be heated by using heat from the heater 12 via the film 10. The film 10 is a metal film and the heater 12 is provided with the heating element on the substrate face on the opposite side of the face in contact with the film 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater for heating provided on one surface of a substrate with a heating element which generates heat when energized, a heating device having the heater, and an electrophotographic static The present invention relates to an image forming apparatus provided as an image heating unit in an image forming process such as an electronic recording method.

[0002]

2. Description of the Related Art Conventionally, many electrophotographic copiers and printers use a contact heating type heat roller fixing system having good thermal efficiency and safety as a fixing means, or an energy saving type film heating type heating device (heating device). Fixing device).

[0003] The heat fixing device of the heat roller fixing system basically has a heating roller (fixing roller) as a heating rotating body and an elastic pressure roller as a pressing rotating body pressed against the heating roller. An unfixed image (toner image) is formed and held in a pressure contact nip portion (fixing nip portion) of the pair of rollers by rotating the rollers, and a recording material (transfer material sheet, electrostatic recording paper, Facsimile paper, printing paper, etc.), and the nip portion is nipped and conveyed, so that the unfixed image is permanently fixed to the surface of the recording material by the heat from the heating roller and the pressing force of the nip portion. The pressure is fixed.

Further, a fixing device of a film heating type is disclosed in, for example, JP-A-63-313182 and JP-A-2-157.
878, 4-44075-44083, 4-20498
No. 0-204984, etc., in which a heat-resistant film (fixing film), which is a heating rotating body, is brought into close contact with a heating body (heating heater) with a rotating body for pressing (elastic roller) and is slid and conveyed. A recording material (transfer material) carrying an unfixed image is introduced into a press-contact nip formed by a heating element and a pressure member with the heat-resistant fixing film interposed therebetween, and is conveyed together with the heat-resistant film. This is an apparatus for fixing an unfixed image as a permanent image on a transfer material by heat from a heating body applied through a heat-resistant film and a pressing force of a pressure nip portion.

In a film heating type heating apparatus, a linear heating element having a low heat capacity can be used as a heating element, and a thin film having a low heat capacity can be used as a film. (Quick start performance improvement) is possible.

[0006]

In the above-described heating apparatus, for example, in a device of a system in which a film is loosely fitted into a film guide and a pressure roller is driven to rotate the film with respect to the pressure roller, Does not have a shift control mechanism for controlling the film so as not to shift more than a predetermined amount in a direction orthogonal to the rotation direction,
When the film is shifted, the shift is suppressed by hitting the regulating member provided in the shifting direction. For this reason, the film is provided with a certain degree of rigidity to prevent the film from buckling due to the biasing force. For this reason, it is difficult to reduce the thickness of the film in order to maintain the rigidity of the film, and there is a disadvantage that thermal conductivity from the heater for heating is inferior.

In order to increase the speed of the image forming apparatus, attempts have been made to improve the heat conduction of the film in the above-mentioned heating apparatus of the film heating system. There is a limit, and the speeding up of the image forming apparatus is limited to about 20 sheets / minute in A4 size.

Therefore, in order to achieve a higher speed, an attempt has been made to use a metal film instead of a heat-resistant resin film. However, since the metal film has no electrical insulation, the heating heater has a contact surface with the heating heater. It has been difficult to maintain the insulation between the metal and the metal film with a conventional coating of glass or the like.

Although the metal film itself has high rigidity, it is susceptible to bending fatigue, so that the metal film is broken at the time of repeated use by deformation at the nip portion. In addition, there is a defect that durability is inferior, such as breaking due to stress at an end portion because of brittleness.

In view of the above, the present invention comprises a metal film and a heating heater having a heating element provided on a substrate surface opposite to a sliding surface of the film, so as to increase the speed of the apparatus, reduce power consumption, and reduce weight. An object of the present invention is to provide a heating device, an image forming device, and a heater for use in the device, which can shorten the time and increase the durability.

A heating heater in which the shape of the substrate surface (sliding surface) on the side opposite to the surface on which the heating element is provided is tapered or R-shaped to suppress the occurrence of frictional resistance and stress on the sliding surface. A heating device and an image forming apparatus, comprising: a heater for heating; and a metal film slidable with the heater, which effectively prevents breakage of the metal film and increases the durability of the apparatus. I do.

[0012]

[Means for Solving the Problems]

[1]: A substrate and a heating element provided on one surface of the substrate and generating heat by energization, and at least one end of a surface of the substrate opposite to the surface where the heating element is provided is tapered. Or a heating heater having an R shape.

[2] The heating heater according to [1], wherein a heat-resistant sliding layer is formed on the surface of the substrate opposite to the surface on which the heating element is provided.

[3] The heater according to [1] or [2], wherein aluminum nitride is used for the substrate.

[4]: A heating heater provided with a heating element which generates heat by energizing the substrate, a supporting member for fixing and supporting the heating heater, and a film sliding on the heating heater. A heating device for heating a material to be heated by heat from the heater through the film, wherein the film is a metal film, and the substrate on the side opposite to the surface where the heater contacts the film; A heating device characterized in that a heating element is provided on a surface.

[5] The heating device according to [4], wherein the film has an endless shape.

[6]: A heating heater provided with a heating element which generates heat by energizing the substrate, a supporting member for fixing and supporting the heating heater, and a cylindrical shape fitted to the heating heater and the supporting member. And a pressure roller that presses against the heater for heating with the film interposed therebetween to form a heating nip portion, and rotates the heated material introduced into the heating nip portion by rotating the pressure roller. In a heating device, which is held and transported together with the film by driving and heat-treats the material to be heated with heat from a heater through the film, the film is a metal film, and the heater contacts the film. A heating device, wherein a heating element is provided on a substrate surface opposite to the surface.

[7]: The substrate of the heater is characterized in that at least one of the two end portions of the side surface of the film in the film moving direction has a tapered shape or an R shape. [4] The heating device according to [5] or [6].

[8]: The heater for heating has a heat-resistant sliding layer on the film side surface [4].
The heating device according to any one of claims 1 to 7.

[0020]

[9]: The film is 20 to 100 μm
The heating device according to any one of [4] to [8], wherein the heating device has a thickness of:

[10]: The film is flexible, [4] to [4].

The heating device according to any one of [9].

[11] Any one of [4] to [10], wherein the film has a release layer provided on a surface opposite to a surface sliding with the heater for heating. The heating device according to Item.

[12] The heating apparatus according to any one of [4] to [11], wherein the heater uses aluminum nitride for the substrate.

[13]: A means for controlling the amount of heat generated by the heating heater based on a signal from a temperature detecting element provided in contact with the film is provided. [4] to [12] The heating device according to claim 1.

[14] The heating apparatus according to any one of [4] to [13], wherein heat-resistant resin coating is applied to both ends of the film.

[15] The heating device according to any one of [4] to [14], wherein both ends of the film are covered with a heat-resistant resin cap having flexibility.

[16]: In an image forming apparatus comprising: an image forming means for forming a developer image on a recording material; and an image heating means for heating the developer image on the recording material. An image forming apparatus comprising the heating device according to any one of the above [4] to [15] as an image heating unit.

<Operation> a. In the present invention, the heating heater has a substrate and a heating element provided on one surface of the substrate and configured to generate heat when energized, and at least one end of a surface of the substrate opposite to the surface on which the heating element is provided. Since the shape of the back heating type is a tapered shape or an R shape, on the surface opposite to the surface on which the heating element is provided,
When the material to be heated is adhered directly or through a film, and the material to be heated or the film and the material to be heated are slid together and heated, the generation of frictional resistance and stress on the sliding surface is reduced. Could be suppressed.

Further, by forming a heat-resistant sliding layer on the surface (sliding surface) of the substrate opposite to the surface on which the heating element is provided,
The generation of frictional resistance and stress on the sliding surface could be further suppressed.

The use of aluminum nitride for the substrate improves the heat transfer of the substrate, shortens the wait time until the substrate rises to a predetermined temperature, and prevents excessive temperature rise in portions not in contact with the material to be heated. Power saving.

B. The present invention has a heating heater in which a heating element that generates heat by energization is provided on a substrate, a support member that fixedly supports the heating heater, and a film that slides on the heating heater, wherein the film In the heating device that heats the material to be heated by the heat from the heater through the heater, by providing the heating element on the substrate surface opposite to the surface where the heater contacts the film, The insulation between the heating element and the film is sufficiently ensured, a metal film can be used as the film, and by using the metal film, the required rigidity can be ensured and the thickness can be reduced. The high thermal conductivity makes it possible to increase the speed of the device, save power, and reduce the wait time.

Further, the substrate of the heater for heating has at least one of the two end portions in the film moving direction on the side surface of the film having a tapered shape or an R-shaped shape. And the stress on the film can be suppressed, and high durability can be achieved.

By providing the heat-resistant heating layer on the film-side surface of the heater for heating, the frictional resistance between the heater and the film and the stress on the film could be further suppressed.

Further, by using aluminum nitride for the substrate of the heater, the heat transfer from the heating element is improved, so that the apparatus can be operated at high speed, power can be saved, and the wait time can be reduced. Further, since the heat transfer property is improved, the temperature difference between the sheet passing portion and the non-sheet passing portion is also reduced, and it is possible to prevent an excessive temperature rise in the non-sheet passing portion.

By applying heat-resistant resin coating to both ends of the film or covering flexible heat-resistant resin caps on both ends of the film, it is possible to effectively prevent breakage of the metal film from the ends. did.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> (1) Example of Image Forming Apparatus FIG. 9 is a schematic sectional view of an image forming apparatus according to the present invention. The image forming apparatus of this embodiment is a laser beam printer using a transfer type electrophotographic process.

In FIG. 9, reference numeral 1 denotes a photosensitive drum;
It has a configuration in which a photosensitive material such as PC, amorphous Se, or amorphous Si is formed on a cylindrical substrate such as aluminum or nickel. The photosensitive drum 1 is driven to rotate in the direction of the arrow, and its surface is first uniformly charged by a charging roller 2 as a charging device. Next, on / off control of the laser beam 3 from a laser scanner, which is an exposure unit, is performed according to image information to perform scanning exposure, and an electrostatic latent image is formed on the photosensitive drum 1. This electrostatic latent image is developed by the developing device 4 and visualized (toner image).
Is done. As a developing method, a jumping developing method, a two-component developing method, or the like is used, and in many cases, a combination of image exposure and reversal developing is used. The visualized toner image is transferred from the photosensitive drum 1 to the transfer material P fed and conveyed at a predetermined timing from the photosensitive drum 1 by a transfer roller 5 as a transfer device. The transfer material P holding the toner image is conveyed to the fixing device 6 and is heated and pressed at the nip portion of the fixing device 6 to be fixed on the transfer material to form a permanent image. On the other hand, the transfer residual toner remaining on the photosensitive drum 1 after the transfer is removed from the surface of the photosensitive drum 1 by the cleaning device 7.

(2) Example of Heating Apparatus a) Overall Schematic Configuration of Apparatus Hereinafter, an example of the heating apparatus of the present invention provided as the fixing apparatus 6 of the above-described image forming apparatus will be described.

FIG. 1 is a schematic sectional view of a film heating type fixing apparatus 6 to which the present invention is applied, and FIG. 2 is a schematic plan view of a heating heater provided in the apparatus 6.

In FIG. 1, reference numeral 10 denotes an endless belt-shaped metal film (fixing film), 12 denotes a heater having a low heat capacity (ceramic heater), and 13 denotes the heater 12.
And a film guide member (stay) having a semicircular arc shape for fixedly supporting the film 10 and guiding the movement of the film 10. The film 10 is externally fitted to an assembly of the heater 12 for heating and the support member 13 in such a manner that the circumferential length has a margin.

Reference numeral 11 denotes a rotatably supported film 10
The pressing roller is a pressing member that presses against the heater 12 through the nip, and also has a function as a driving roller that drives the film 10 by being rotationally driven by driving means (not shown). The pressure roller 11 is made of a metal core 11 such as aluminum.
a, a silicone rubber layer 11b is provided on the
Is provided with a PFA tube layer 11c as a release layer on the outer periphery of.

By rotating the pressure roller 11, the film 10 slides on the lower surface of the heater 12 in the clockwise direction indicated by the arrow in FIG. The transfer material P carrying the unfixed toner image T conveyed from the image forming unit shown in the drawing is rotationally driven at substantially the same speed as the conveyance speed without wrinkles. The heating body 12 is heated by electric power supply, and in a state where the film 10 is rotationally driven, a heating nip portion (fixing nip portion) formed by deformation of the release layer 11c and the rubber layer 11b of the pressure roller 11. A transfer material (recording material, heated material) P is introduced between the N film 10 and the pressure roller 11, and the transfer material P is brought into close contact with the outer peripheral surface of the film 10 so as to overlap with the film. The transfer material P is passed through the fixing nip N, and a heater 1
2 is applied through the film 10, and the unfixed toner image T on the transfer material P is heated and fused. After passing through the fixing nip, the transfer material P subjected to the fixing process is separated from the film 10 and discharged out of the apparatus.

B) Metal Film 10 The metal film 10 used in the apparatus of this embodiment has a total thickness of 100 μm or less, preferably 60 μm or less and 20 μm or more in order to reduce the heat capacity and improve the quick start property. Ni electroformed film, stainless seamless film or the like is used.

The metal film 10 is made of a material that can be electroformed, such as Ni, and is subjected to an electroforming method. A cylindrical master such as Sus, copper, or the like is formed of nickel sulfamate, nickel sulfate, or the like.
A thin metal film can be obtained by immersing in an electroforming solution such as a nickel acetate solution, forming a Ni layer of a predetermined thickness by electroplating, and removing the mold. N in a similar way
A film of an i-Co alloy or a Ni-iron alloy can also be obtained. Next, an adhesive layer is applied to the surface of the Ni film, and PF
A powder is electrostatically coated or PFA or PTFE dispersion is spray-coated, and then fired or a PFA tube is coated on a metal film and welded to form a fluororesin layer having a predetermined thickness.

C) Pressure Roller 11 The pressure roller 11 performs a surface roughening treatment such as blasting of a metal core 11a such as iron or aluminum, and then performs cleaning, and then inserts the metal core 11a into a cylindrical mold. Liquid silicone rubber is injected into the mold and cured by heating. At this time, a resin tube layer 11c such as a PFA tube is used as a release layer on the pressure roller surface layer.
By forming a tube in which a primer has been previously applied to the inner surface of the mold in advance, a heat-hardening of the rubber and the adhesion of the tube and the rubber layer 11b are performed. After the pressure roller molded in this way is released from the mold, 2
Next vulcanization is performed.

D) Heating heater 12 The heating heater 12 is provided with an energizing heating element (resistance heating element) 12b as a heat source that generates heat by supplying power on the back surface of a flat substrate 12a. Electric power is supplied to the current-carrying heating element 12b through the electrode sections 12c provided at both ends to generate heat, and the heat causes the entire substrate to quickly rise in temperature.

The substrate 12a of the heater 12 of this embodiment is made of aluminum nitride (hereinafter abbreviated as AlN). As shown in FIG. 2, a heating element 12b made of AgPd (silver / palladium) is formed on a AIN substrate by screen printing and then baked to form a predetermined pattern, on which a glass layer 12d is coated as a heating element protection layer. . Electrodes 12c are formed at both ends of the heating element 12b to supply electricity to the heating element. A temperature detecting element (14 in FIG. 1) is brought into contact with the glass layer 12d, and the power supply to the heating element is controlled by a control circuit (not shown). The surface of the heater having the above-described structure having the heating element is connected to the film guide member 13.
, And the back surface is used as a sliding surface with the fixing film 10. This AlN substrate has the following advantages mainly over the conventional alumina substrate.

The thermal conductivity of the AlN substrate is 220 (W / m ·
° k) and about 11 times higher than that of the alumina substrate (20 W / m · ° k), and the heat capacity is as small as about 2/3 if the volume is the same. Since uniformity is possible and the thermal shock resistance is about twice, many advantages are obtained, such as making the heating element 12b thinner and less likely to damage the substrate due to rapid heating even when used at a high temperature.

In particular, since the AlN substrate has a thermal conductivity that is about two orders of magnitude higher than that of the glass coat layer, the thickness of the substrate is at least 10 times greater than the glass coat layer (the substrate thickness is about 0.5 to 0.8 mm, (In this embodiment, the thickness is 0.65 mm. On the other hand, the thickness of the glass is about 30 to 60 μm). A backside heating type A in which the element 14 is disposed and the backside of the substrate contacts the fixing nip surface
The use of the 1N heater 12 makes it possible to stand up more quickly than the conventional heater of an alumina substrate, and also has a high thermal conductivity so that the substrate can be uniformly and widely heated. Be able to maintain. Further, since the temperature distribution in the longitudinal direction is also easily made uniform, there is an effect of alleviating the excessive temperature rise in the non-sheet passing portion, which is a problem when small size paper is continuously passed.

E) Function and effect of this embodiment As described above, the metal film 10 is used as the fixing film.
By using a back-type heater 12 having an AlN substrate as a heating heater that slides with the metal film 10, the film 10 is formed thin while having the rigidity required as a tensionless film. In addition, the thermal conductivity is good in terms of material, and therefore, the device can be operated at high speed (high throughput), power can be saved, and the wait time can be reduced.

Further, since an insulating layer having a sufficient thickness (0.65 mm AlN substrate as described above) is formed between the current-carrying heating element and the metal film, not only the initial withstand voltage but also the wear due to durability is reduced. Since there is no need to worry, it is possible to provide the heat fixing device 6 with high safety for a long time.

Specifically, a comparison between the apparatus having this configuration and a conventional heat fixing apparatus using a heat-resistant resin film revealed that
The following results were obtained.

In the conventional apparatus, the film 10 is made of resin and has a thickness of 50 μm and an inner diameter of 25 mm, and the pressure roller 11 has a PFA having an outer diameter of 20 mm and a roller hardness of 40 degrees.
Using a silicone rubber roller covered with a tube, a heating heater 12 is formed on an alumina substrate having a substrate width of 7 mm and a thickness of 0.65 mm with an electric heating element layer having a total resistance value of 12.5 Ω, and an insulating layer formed thereon. An overcoat glass layer was formed, and a temperature detecting element 14 such as a thermistor was brought into contact with the overcoat glass layer to control the heater for heating at a constant temperature.
When power of 800 W was supplied in such a configuration and a recording material having an unfixed image was passed about 5 seconds after the power was supplied, the image forming speed was 100 mm / sec (about 16 sheets per minute in A4 size paper). Good fixing performance was obtained only up to a speed of about (feed speed).

On the other hand, in the apparatus of this embodiment, Ni electroforming is used as the film 10, the thickness is 45 μm, the substrate is made of AlN, and the other structure is the same as the conventional apparatus. 2 per minute in size
Sufficient fixability of the unfixed toner image on the recording material was obtained at an image forming speed of about two paper feed speeds).

Further, by using a heater for heating the AlN substrate having good thermal conductivity and using a metal film of Ni electroforming, it is possible to drastically reduce the non-sheet-passing temperature rise when small-size paper is passed.
In the conventional heat fixing apparatus, when an envelope having a width of about 100 mm is passed, the throughput is determined by the non-sheet passing temperature increase amount. Therefore, the throughput is limited to 8 sheets / min even if the image forming speed is increased. Was. However, when a similar test was conducted with the heat fixing device of the present embodiment, it was possible to obtain an envelope throughput of 16 sheets / min. A more detailed study revealed that the effect of the AlN heater made it possible to achieve a throughput of 5 sheets compared to the conventional configuration, and that the effect of the Ni electroformed film made it possible to achieve an additional throughput of 3 sheets / min. .

<Second Embodiment> FIG. 3 shows a second embodiment of the present invention.
FIG. 4 is a schematic cross-sectional view of a heat fixing device 6 according to an embodiment of the present invention, and FIG. In the present embodiment, a backside heating type heating element using an AlN substrate is used as the heating heater in the same manner as in the above embodiment, and the shape of at least one end of both ends in the sheet passing direction of the surface in contact with the metal film 10 is used. Has a tapered shape (slope shape) or an R shape.

As shown in FIGS. 3 and 4, in this embodiment, both end portions 12e of the corresponding contact surface are tapered, and a glass coating layer 12 having a thickness of 5 to 10 μm is further formed thereon as a heat-resistant sliding layer.
c is formed.

Conventionally, the heating heater supporting portion of the film guide member 13 has a shape such that the film guide member always protrudes toward the pressure roller with respect to the heater surface (that is, the lower surface 13a of the guide member is lower than the heater surface 12f). FIG. 4
However, in this embodiment, the heater surface protrudes from the film guide member toward the pressure roller (that is, the heater surface 12f is the guide member lower surface 13a).
4 in FIG. 4).

With such a configuration, the amount of local deformation at the nip portion N of the metal film is reduced, the sliding force at the substrate edge portion is reduced, and the stress on the metal film during rotation is suppressed. ing.

That is, according to this embodiment, it is possible to greatly improve the durability of the metal film in addition to the functions and effects described in the above embodiment.

The above effect can be made more effective by providing a thin overcoat glass layer 12g as a rubbing force reducing layer on the film contact surface of the heater 12. Since the glass layer 12g is a thin glass layer, there is little hindrance to heat conduction, and there is almost no effect on the fixability.

The taper or R shape of this embodiment can be formed by grinding an AlN substrate after firing, and since the workability is better than that of an alumina substrate, the cost increase accompanying the shape processing can be minimized. It is possible.

Also in this configuration, as in the above-described embodiment, good fixability can be exhibited even when the image forming speed is 140 mm / sec, and the durability of the metal film can sufficiently withstand 200,000 sheets of A4 size paper. became. It has been found that if the taper and the R shape are too large, the contact area between the heater for heating and the metal film is reduced, which adversely affects the fixing property, and if it is too small, it is difficult to obtain the effect of improving the durability. Therefore, the taper shape is such that the angle A with respect to the heater lower surface shown in FIG.
It is preferably 0.2 mm. The same effect can be obtained by using an R shape instead of the tapered shape.
Preferably between 3 and 1.0 mm.

In this embodiment, the heating heater is provided with a taper or an R-shape at both ends in the sheet passing direction. However, similar effects can be obtained by providing only one of them. In particular, it has been found that by providing it on the upstream side in the paper passing direction, durability comparable to that provided on both ends can be obtained.

<Third Embodiment> FIG. 5 shows a third embodiment of the present invention.
1 is a schematic cross-sectional view of a heat fixing device 6 according to an embodiment of the present invention.
The present embodiment is characterized in that the thermistor 14 as the temperature detecting element is not provided on the heater substrate, but is brought into contact with the inner peripheral surface of the metal film on the downstream side in the paper passing direction of the nip portion.

When the heater temperature is controlled by the thermistor 14 on the heater substrate as in the first embodiment,
The heater substrate 1 is located between the thermistor 14 and the fixing nip N.
2a, the heating element 12b, and the insulating glass layer 12d were provided, and there was a difference between the temperature of the heater (detection temperature of the thermistor) and the temperature of the fixing nip N. Therefore, in order to predict the difference between the temperature of the heater and the temperature of the fixing nip N, an optimum heater control temperature is determined based on information such as a printing interval and the number of printed sheets. In this method, it is necessary to create an optimal heater temperature control table based on a huge amount of data,
He spent a lot of time deciding the conditions. Further, the temperature difference between the temperature of the thermistor portion on the heater substrate and the temperature of the fixing nip portion varies due to the variation of the thickness of the insulating glass layer for each heater, and the cost tends to increase because the thickness variation of the insulating glass layer is reduced.

Therefore, in this embodiment, the temperature of the inner peripheral surface of the metal film downstream of the nip is detected, and since the thermal conductivity of the metal film 10 is good, it is possible to know the temperature of a place closer to the fixing nip portion N. Can be. Thereby, the temperature control of the heat fixing device 6 can be further simplified, and at the same time, the accuracy can be improved. Further, the thickness variation of the overcoat glass 12g on the heater substrate can be tolerated in a wide range, and the heater cost can be reduced.

In this embodiment, a thermistor chip as the temperature detecting element 14 is fixed to the film guide 13 via a heat-resistant and heat-insulating elastic layer such as a sponge, and a heat-resistant resin such as a polyimide tape is formed on the surface of the thermistor chip on the film side. A protective layer and a sliding layer made of a film are formed. Although the contact position is preferably closer to the nip portion, it has been found in experiments that sufficient temperature detection accuracy can be obtained even if the contact position is as far as 5 mm downstream from the nip portion N.

<Fourth Embodiment> FIG. 6 shows a fourth embodiment of the present invention.
It is a front view of the metal film used for the heat fixing device 6 which is an example of Embodiment. In this embodiment, polyimide, PTFE, PFA, PEEK, PES, P
When a heat-resistant resin coating such as AI, PPS, or liquid crystal polymer is applied, and a biasing force acts during rotation of the metal film 10, sliding with a flange portion (a regulating member (not shown)) fixed to the apparatus main body is performed. It is characterized in that a crack is prevented from being generated at the end of the film due to rubbing.

In this embodiment, the polyimide resin layer 10a is formed by dissolving a thermoplastic polyimide resin at both ends in a solvent, coating only the both ends of the metal film in the solution by dipping, and drying by heating. At this time, the thickness of the resin layer is preferably between 5 and 20 μm. If the thickness is too small, the durability against abrasion cannot be sufficiently secured. It has been found that when the shape is imitated, excessive stress is caused and a crack is generated at that portion. Further, by forming a thermo-flexible resin layer in which a fluororesin powder is dispersed on both end resin layers 10a, the sliding resistance can be reduced. It is preferable to provide the protection layers 10a at both ends at a relatively low cost since the heat deterioration can be prevented and the processing steps can be simplified.

When the metal film 10 provided with the flexible protective layers 10a made of heat-resistant resin at both ends as described above was applied to the heat fixing device 6 of the second embodiment, the A4 size paper was 30 It was found that the end portion did not crack even after passing many sheets, and showed very good durability performance.

In this embodiment, the heat-resistant resin coating 10a is applied to both ends of the metal film. However, for example, a heat-resistant resin having sufficient flexibility by being partially cut as shown in FIG. 7 is used. It is also possible to obtain the above effect by attaching the caps 60 to both ends.

The cap 60 has a gap 60a for fitting the film 10 on the surface on the film side, and a cut 60b arranged on the surface in the circumferential direction.

At this time, it is preferable that the cap 60 does not adhere to the metal film 10, and the gap 60 a of the cap 60 is smaller than the thickness of the metal film and is fitted with a light press-fit. In such a cap 60, even if the thickness of the resin is thick, the flexibility is not impaired by the cuts 60b, and the metal film shape does not follow the heater surface. Can be shown. At this time, the thickness t of the cap is 0.1 to 0.5.
It has been found that good moldability, abrasion resistance and flexibility are obtained in the range of mm. The material of the cap 60 is polyimide, PTFE, PFA, PEEK, PES, PA
Heat-resistant resins such as I, PPS, and liquid crystal polymers are preferably used. When the cap 60 formed by dispersing a fluororesin powder in a polyimide resin and having a thickness t of 0.2 mm and formed into a shape as shown in FIG. 6 was applied to the heat fixing device 6 of the second embodiment, the A4 size It was found that even when 400,000 sheets of paper were passed, no cracks were generated at the ends, and very good durability was exhibited.

<Others> In the above embodiment, the example of the apparatus of the tensionless type is shown. However, the present invention is not limited to this, and an apparatus in which a metal film is suspended between a plurality of members may be used.

For example, as shown in FIG.
The endless belt-shaped metal film 10 may be suspended between two members, the heater 12 supported by the driving roller 15 and the driving roller 15, and the driving roller 15 may be driven to rotate.

[0077]

As described above, according to the present invention,
By providing a metal film and a heater for heating provided with a heating element on the substrate surface opposite to the sliding surface with the film, it is possible to increase the speed, reduce power consumption, shorten the wait time, and increase the durability. The present invention can provide a heating device, an image forming device, and a heating heater used in the device.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a heat fixing device according to a first embodiment of the present invention.

FIG. 2 is a schematic plan view of a heating heater provided in the heat fixing device.

FIG. 3 is a schematic sectional view of a heat fixing device according to a second embodiment of the present invention.

FIG. 4 is an enlarged schematic sectional view of a nip portion of the heat fixing device.

FIG. 5 is a schematic sectional view of a heat fixing device according to a third embodiment of the present invention.

FIG. 6 is a front view of a metal film applied to a heat fixing device according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a metal film cap shape applied to the heat fixing device according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram of another configuration of the heat fixing device according to the present invention.

FIG. 9 is a schematic sectional view of an image forming apparatus to which the heat fixing device of the present invention is applied.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor drum 2 Charging roller 6 Heat fixing device 10 Fixing film 11 Rotating body for pressurization

Claims (16)

[Claims] 1. A substrate and a heating element provided on one surface of the substrate and generating heat by energization, wherein at least one end of a surface of the substrate opposite to the surface on which the heating element is provided is tapered. A heating heater having a shape or an R shape. 2. The heating heater according to claim 1, wherein a heat-resistant sliding layer is formed on a surface of the substrate opposite to a surface on which the heating element is provided. 3. The heater according to claim 1, wherein aluminum nitride is used for the substrate. 4. A heating heater having a substrate provided with a heating element that generates heat by energization, a support member for fixing and supporting the heating heater, a film sliding on the heating heater,
A heating device that heat-treats a material to be heated by heat from the heater through the film, wherein the film is a metal film, and the heating heater is opposite to a surface in contact with the film. A heating element provided on the side substrate surface. 5. The heating device according to claim 4, wherein the film has an endless shape. 6. A heating heater having a substrate provided with a heating element which generates heat when energized, a supporting member for fixing and supporting the heating heater, and a cylindrical film externally fitted to the heating heater and the supporting member. And a pressure roller that presses against the heater for heating with the film interposed therebetween to form a heating nip portion, and heats the material introduced into the heating nip portion by rotating the pressure roller. Sandwiched and transported with the film,
In a heating device for heating the material to be heated with heat from a heater for heating via the film, the film is a metal film, and the heater for heating is disposed on a substrate surface opposite to a surface in contact with the film. A heating device comprising a heating element. 7. The substrate of the heater for heating, wherein at least one of the two end portions of the side surface of the film in the film moving direction has a tapered shape or an R shape. 7. The heating device according to 4, 5, or 6. 8. The heating device according to claim 4, wherein the heating heater has a heat-resistant sliding layer on a film-side surface. 9. The heating device according to claim 4, wherein the film has a thickness of 20 to 100 μm. 10. The heating device according to claim 4, wherein the film has flexibility. 11. The film according to claim 4, wherein a release layer is provided on a surface of the film opposite to a surface on which the heater slides. Heating equipment. 12. The heating heater according to claim 4, wherein the substrate is made of aluminum nitride.
The heating device according to claim 1. 13. A device according to claim 4, further comprising means for controlling a heating value of a heating heater based on a signal from a temperature detecting element provided in contact with said film.
3. The heating device according to any one of 2. 14. The heating apparatus according to claim 4, wherein heat-resistant resin coating is applied to both ends of the film. 15. The heating device according to claim 4, wherein both ends of the film are covered with a heat-resistant resin cap having flexibility. 16. An image forming apparatus comprising: image forming means for forming a developer image on a recording material; and image heating means for heating the developer image on the recording material. An image forming apparatus comprising the heating device according to any one of claims 4 to 15 as a unit.