JPH1116667A - Heater, heating device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a good heating characteristic, increase the speed of an apparatus, detect a responsive temperature suitable for the high speed, increase the degree of freedom in material selection, and apply a material to a member that rubs with a heater. To provide a heater, a heating device, and an image forming apparatus capable of suppressing the load on the image forming apparatus. SOLUTION: A heat generating substrate 6 'is brought into contact with the back surface of a heat conductive plate 16 wider than the heat generating substrate 6', and at least one of the heat conductive plate surfaces 16 in a width direction has a curved shape. Use as a heating surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater provided with a resistance heating element on a substrate, and a heating device provided with the heater.
And an image forming apparatus such as a printer, a copying machine, and a facsimile of an appropriate image forming method such as an electrophotographic method and an electrostatic recording method.

[0002]

2. Description of the Related Art Conventionally, as a fixing method of an unfixed image on a recording material in an apparatus such as a printer, a copying machine, a facsimile, etc. using an electrophotographic method, a contact heating type fixing device having good thermal efficiency and safety is widely used. Are known. Especially in recent years, from the viewpoint of promoting energy saving, thermoelectric efficiency is high,
As a system in which the apparatus rises quickly, a film heating type apparatus that heats through a film having a small heat capacity has attracted attention, and is disclosed in JP-A-63-313182, JP-A-2-157878, and 4-44.
075-44083 and 4-204980-204984.

[0003] The configuration of the film heat fixing device includes a method of transporting the film between the pressure roller while applying tension using a transport roller and a driven roller dedicated to transport the film, and a method of adding a cylindrical film. There is a method of driving with a conveying force of a pressure roller. The former has an advantage that film transportability can be enhanced, and the latter has an advantage that a configuration can be simplified and a low-cost fixing device can be realized.

As a specific example, the latter pressure roller driven film fixing device will be described. FIG. 9A is a schematic sectional configuration diagram of the fixing device.

In FIG. 1, an image T formed of toner on a recording material 1 is formed by a pressure roller 3 made of heat-resistant rubber.
The cylindrical fixing film 4 is pressed between the pressure roller 3 and the pressure roller 3 to a total pressure of about 4 to 15 kgf, and is rotated and conveyed by a frictional force along with the rotation of the pressure roller along the heater holder 10 also serving as a film guide member. And is heated and pressurized by the heater 5 via the fixing film 4 to be fixed.

At this time, the fixing film 4 has a thickness of 1 in order to reduce the heat capacity and improve the quick start property.
Polytetrafluoroethylene (hereinafter abbreviated as PTFE), perfluoroalkoxytetrafluoroethylene copolymer (hereinafter abbreviated as PFA) having heat resistance, release property and durability of 00 μm or less, more preferably 40 μm or less and 20 μm or more, PPS is applied to the surface of PPS monolayer film or polyimide, polyamideimide, PEEK, PES, etc.
It is composed of a composite layer film coated with TFE, PFA and FEP as a release layer. On the other hand, the heater has a pattern in which a heating element 8 is formed on a heater substrate 5 made of a heat-resistant insulating material such as ceramic, the front surface is protected by heat-resistant glass 9, and the temperature detecting element 7 is arranged on the back surface of the substrate. The temperature of the fixing device is controlled by detecting the temperature of the back surface of the substrate.

FIG. 9B is a plan view of a heating element forming surface of the heater. The heating element 8 is formed of a belt-like pattern. In this example, two heating elements are used to increase the heating width and improve the fixing property even slightly. It is formed by folding back. Here, the material of the heating element 8 is silver palladium (Ag / Pd), RuO ₂ , Ta ₂ N
And the like, and the silver platinum (A) formed on the substrate surface
g / Pt) and generate heat when energized from the energizing electrode 11.

FIG. 9C is a plan view of the back surface of the substrate. In order to control the substrate temperature, the temperature detecting element 7 is formed of low-resistance silver palladium in which the ratio of Pd is suppressed to 30% or less. Temperature detection electrode 1 formed on the substrate surface via the sensing element wiring 7 ′ and the conduction through hole 11 ″.
1 ', and this electrode is connected to a detection circuit of the apparatus main body.

Further, on the substrate, as a safety measure, a through hole 1 is provided as a safety measure to prevent a problem such as a fire when the heater is heated to a predetermined temperature or more by some factor.
2 is provided near the edge of the substrate. This through hole 12
When the substrate temperature reaches an excessive temperature region due to the presence of
Due to the thermal expansion of the ceramic substrate, the stress difference generated at the boundary between the portion having the through-hole 12 and the portion not having the through-hole 12 also increases, and cracks occur around the region of low mechanical strength between the substrate end and the through-hole 12, The heating element formed on the substrate is also disconnected, so that thermal runaway of the heater is stopped.

However, if the breakage of the heating element due to the through hole occurs on the temperature detection circuit side, there is a risk that the heating element connected to the AC circuit and the wiring for the detection element connected to the DC circuit may be short-circuited at the end of the broken substrate. Therefore, the longitudinal position of the through hole 12 is preferably provided on the power supply electrode side as far away from the temperature detection circuit side as possible. Conversely, even when the power supply electrode is extremely close to the power supply electrode, the voltage of the disconnection portion is too high and the disconnection occurs. In this case, the conventional apparatus is provided at a position near the power supply electrode inside the paper passing area of A4 size paper because the generation of sparks due to contact between the heating elements at the time becomes strong.

As described above, various image forming apparatuses such as a printer using the above-described fixing device can eliminate the need for preheating during standby due to the high heating efficiency and the rising speed, and eliminate the waiting time. It has many advantages, especially since the method of driving a cylindrical film with the conveying force of a pressure roller can be realized at low cost. It is as expected.

However, in order to realize a high speed, it is necessary to set the fixing temperature even higher in order to supply sufficient thermal energy to the paper (heated material) having a short passage time. When passing size paper, the temperature difference between the paper passing area and the non-paper passing area is enlarged, which leads to an increase in the heat resistance of peripheral members due to excessive temperature rise in the non-paper passing area, and an increase in thermal stress on the heater substrate. Accordingly, it is necessary to take measures such as improvement of substrate strength.

Therefore, as a first problem, it is required to improve the fixing property without increasing the fixing temperature as much as possible, and it is necessary to transfer heat from the heating element of the substrate to the fixing nip surface more quickly, or By substantially increasing the temperature of the front surface of the substrate in the nip portion and substantially increasing the nip width,
It is necessary to take measures to increase the amount of heat supplied during fixing.

As a second problem, it is important to improve the uniformity of the temperature in the longitudinal direction of the heater substrate. As described above, this can be done by increasing the temperature rise of the non-sheet passing portion, relaxing the heat resistance conditions of the peripheral members of the non-sheet passing portion, expanding the range of usable materials, and increasing the temperature of the non-sheet passing portion. This is because it is necessary to prevent

In order to satisfy the above-mentioned problems at the same time, a member having as high a heat conductivity as possible while having an insulating property is interposed between the heating element of the heater and the fixing nip surface so that the thickness and the lateral direction can be improved. It is effective to increase the heat mobility. In recent years, as a ceramic substrate, an aluminum nitride (hereinafter abbreviated as AlN) substrate having higher thermal conductivity than an alumina substrate conventionally used for a heater has been developed. The AlN substrate has advantages mainly in characteristics as shown in Table 1 as compared with the conventional alumina substrate.

[0016]

[Table 1] As can be seen from Table 1, since the thermal conductivity of AlN is about 11 times higher than that of alumina, it is possible to quickly raise the temperature of the substrate and make the temperature distribution uniform with the same input energy, and the thermal shock resistance is about 2 times. Therefore, even if the heating element is made thinner and used at a high temperature, many advantages can be obtained such that the substrate is hardly damaged by rapid heating.

In particular, since the AlN substrate has higher thermal conductivity than the glass coat layer, an AlN substrate 5 'is used as a heater substrate as shown in FIG. After forming the coat layer 9, FIG.
(B) As shown in FIG.
As shown in FIG. 10 (C), a backside electrode 14 formed on the backside of the substrate is connected to an AC power supply via 1 ", and a backside heating type AlN heater 5 'using the backside of the substrate as a heating surface is used. Compared to the conventional apparatus using an alumina heater, it rises more quickly and has high thermal conductivity in the nip width direction (paper transport direction). In addition, the temperature distribution in the longitudinal direction can be easily made uniform, so that excessive temperature rise in the non-sheet passing portion, which is a problem when small size paper is continuously passed, can be alleviated. .

However, unlike the conventional heater, the backside heating type heater cannot provide the temperature detecting element on the surface opposite to the surface on which the heating element is formed. Therefore, as can be seen from FIG. Is pressed against the glass-coated surface on the heating element forming surface side by using the pressure spring 13, and the temperature control of the heating surface is improved even though the temperature rise of the heating surface is improved by improving the thermal conductivity of the substrate. The temperature data which is the basis of the above can use only the detected temperature through the glass layer 9 having a lower thermal response, which hinders realizing highly accurate temperature control corresponding to high speed.

Conventionally, when a heater is bonded to a heater holder, the surface of the heater may be vertically displaced from the lowermost point of the heater holder within a mounting tolerance range. Similarly, when fixing the type AlN heater, the heater surface may be shifted vertically. As shown in the enlarged view of the nip portion on the heater side in FIG. 11, the heater is mounted on the heater holder by thermosetting bonding with the heater surface being in contact with the lower surface (heater support seating surface) 10c of the heater substrate support 10 '. Although it is fixed by the agent 15 and an extreme height deviation can be prevented, the processing accuracy and the mounting error of the heater substrate and the support member are reduced as shown in FIG.
When the heater surface is mounted above the lowermost point of the heater holder, the degree of rubbing with the edge of the lowermost point of the heater holder increases, and when the fixing speed is increased, the rubbing is caused by this rubbing. There is a problem that the durability life of the fixing film 4 is reduced.

On the other hand, when the fixing film 4 is mounted downward as shown in FIG. 11B, the fixing film 4 is easily damaged at the edge of the AlN substrate. In this case, particularly, the edge of the ceramic substrate 5 'comes into direct contact with the back surface by heating. Therefore, the adverse effect on the fixing film 4 is greater than when the heater is in contact with the glass coat surface as in the conventional heater.

Further, in order to realize further high-speed fixing, there is a method of improving the thermal conductivity of the above-mentioned heater substrate and further improving the thermal conductivity of the fixing film. In recent years, a metal film made of Ni electroforming or the like has been developed as a fixing film having improved heat conduction. When a Ni electroformed film having the same thickness as a conventional polyimide film is used, its thermal conductivity is improved up to about 400 times, which is very effective as a means for solving the above problems.

However, there is a problem peculiar to a metal film, and a configuration which takes this into consideration is required. FIG.
As shown in FIG. 12, the flexibility of the metal film 4 ′ is lower than that of a polyimide film made of resin, and the strength of the metal film 4 ′ causes the substrate to be hardened as shown in FIGS. 12 (A) and (B). Irrespective of whether the film is fixed vertically, contact with the heater in the nip portion is greatly impaired, and as a result, there is a problem that the fixing property is deteriorated as compared with the case where a conventional film is used.

[0023]

SUMMARY OF THE INVENTION An object of the present invention is to improve the heating characteristics (fixing property) at a high speed, to enable high-speed temperature detection with high responsiveness,
It is required to use a material having high thermal conductivity, such as AlN, in order to improve the fixing property by increasing the heat mobility of the heater, and the range of material selection is limited. The degree of rubbing of the film with the peripheral members increases, and the durability of the film decreases, and the film is rubbed strongly against the heater, the support member, and the like due to a mounting error of the heater, and is damaged.

An object of the present invention is to solve the above-mentioned problems, obtain good heating characteristics, increase the speed of the apparatus, detect responsive temperature suitable for the increase in speed, increase the degree of freedom in material selection, and increase the degree of freedom in selecting a heater. It is an object of the present invention to provide a heater, a heating device, and an image forming apparatus capable of suppressing a load on a member rubbing with the heater.

[0025]

[Means for Solving the Problems]

[1]: A heater characterized in that a heat-generating substrate is brought into contact with the back surface of a heat conductive plate, at least a part of the surface of the heat conductive plate is formed into a curved surface, and the surface of the heat conductive plate is used as a heating surface.

[2] A heater characterized in that a heat-generating substrate is brought into contact with the back surface of a heat conductive plate wider than the heat-generating substrate, and the surface of the heat conductive plate is used as a heating surface.

[3]: The heat-generating substrate is brought into contact with the back surface of the heat-conducting plate wider than the heat-generating substrate, and at least one of the heat-conducting plate surfaces in the width direction is curved, and the surface is used as a heating surface. A heater characterized in that it is used.

[4] The heater according to [2] or [3], wherein a temperature detecting means electrically independent from the heat generating substrate is provided on a back surface of the heat conducting plate.

[5]: In the heater of [1], [2], [3] or [4], the heating substrate is formed by forming a resistance heating element which generates heat by energization on a ceramic substrate. A heater characterized in that:

[6] The heater according to [5], wherein the heat-generating substrate has a structure in which a substrate surface on which a resistance heating element is not formed is brought into contact with the heat-conducting plate.

[7]: In the heater of [5 or [6,
The heater, wherein the ceramic substrate is an aluminum nitride substrate.

[8] The heater according to any one of [1] to [7], wherein the heat conduction plate has a thickness of 30 μm to 3 μm.
A heater characterized in that a metal film having a thickness of 00 μm is press-formed.

[0033]

[9]: The heater according to any one of [1] to [8], a support member of the heater, and a press-contact nip portion formed directly or via an interposed member on a heating surface of the heater. And a heating member for applying heat from the heater to the material to be heated conveyed in the press-contact nip portion.

[10] The heater according to any one of [1] to [8], a supporting member of the heater, a film moving in contact with a heating surface of the heater, and A pressure roller that forms a pressure contact nip by pressing against the heating surface via the film, and the film to be heated is transported between the film of the pressure contact nip and the pressure roller. A heating device for applying heat from a heater through the heating device.

[11]: In the heating device of [10],
A heating device, wherein the film has an endless shape.

[12] In the heating device of [10],
A heating device, wherein the film is a metal film.

[13]: [10], [11] or [1]
2) The heating apparatus according to 2), wherein the film has a thickness of 20 to 100 μm, and a fluororesin release layer having a thickness of 10 to 30 μm is provided on the surface of the film. .

[14]: [10], [11], [12]
Alternatively, in the heating device of [13], a slidability improving layer is provided between the film surface and the heat conductive plate heating surface.

[15]: In the heating device of [14],
A heating device, wherein a diamond-like carbon layer is provided on the heat conductive plate heating surface as the slidability improving layer.

[16]: In the heating device of [14],
The film, a resin layer is formed on both sides of the metal film by a dipping method in which the metal film penetrates the resin solution, one of the resin layers as a release layer, the other as a slidability improving layer A heating device characterized by being used.

[17]: In the apparatus according to [16], the resin layer is obtained by dispersing a thermal conductivity and abrasion resistance improving agent in a mixed film of polytetrafluoroethylene and perfluoroalkoxytetrafluoroethylene copolymer. A heating device comprising:

[18]: The apparatus according to [17], wherein the thermal conductivity and wear resistance improving agent is a ceramic filler of alumina, AlN, or boron nitride (hereinafter abbreviated as BN). apparatus.

[19] In the heating device according to any one of [10] to [18], a heating area is provided in a longitudinal direction of a heating area on an upstream side of a pressing nip portion in a film moving direction of the film guide member also serving as the supporting member. A driven roller that uniformly contacts the film.

[20] The heating apparatus according to any one of [10] to [19], wherein the heat-generating substrate is fixed on the heat-resistant resin substrate via a heat insulating material, Is connected to the supporting member via an elastic member.

[21]:

Any one of [9] to [20]
The heating device according to item 1, wherein the heating surface side of the heat conducting plate is formed with an inverted crown shape that is thinner at a central portion in the longitudinal direction of the heating surface and increases in thickness toward both ends. apparatus.

[22]:

Any one of [9] to [21]
3. The heating device according to claim 1, wherein the width of the substrate in the direction of the material to be heated is narrower than the width of the press-contact nip portion.

[23]:

Any one of [9] to [22]
Item 3. The heating device according to Item 1, wherein the surface of the heat conducting member has a curved shape on an upstream side and a downstream side in a conveying direction of the material to be heated.

[24]:

Any one of [9] to [23]
In the heating device described in the paragraph, the heater is mounted so that the heating surface protrudes from the surface of the support member, and the curved surface of the boundary between the heating surface and the support member surface is formed by the tolerance of the position of the heating surface at the time of the mounting. A heating device provided over the above range.

[25]:

Any one of [9] to [24]
3. The heating device according to claim 1, wherein the temperature detecting element is provided downstream of the heat-generating substrate on the back surface of the heat-conducting member in the material-to-be-heated conveying direction.

[26] An image forming apparatus comprising: an image forming means for forming an unfixed developer image on a recording material; and an image heating means for heating the recording material carrying the developer image. The image heating means

[9] An image forming apparatus, which is the heating apparatus according to any one of [9] to [25].

(Function) That is, the heating substrate of the heater is brought into contact with the back surface of the heat conducting plate, at least a part of the surface of the heat conducting plate is formed into a curved surface, and the surface is used as a heating surface. When the heating surface protrudes from the support member surface and is supported, damage to a member that slides in contact with the heater, for example, a fixing film is prevented. In addition, if the curved surface falls within the range of contacting the sliding member, even if the mounting position of the heater changes, damage to the sliding member is prevented, so that the tolerance of the mounting position of the heater is widened.

Also, the heat generating substrate of the heater is brought into contact with the back surface of the heat conductive plate which is wider than the heat generating substrate, and the surface of the heat conductive plate is used as a heating surface, so that the width of the heat generating substrate heating element is reduced. Even so, the heating surface can be widened.

In particular, when the heating substrate has a configuration in which a resistance heating element is provided on a ceramic substrate, the ceramic substrate is required to be insulative and have high thermal conductivity, and the range of material selection is narrow. . On the other hand, as long as the heat conductive plate has high thermal conductivity, it is not necessary to be insulative, and a wide range of materials can be selected. The heater can be easily manufactured by making the heat conductive plate narrow so that it can be sagged and widening the heat conductive plate so as to secure a sufficient heating area.

Further, since the heat conducting plate is wider than the heat generating substrate, it is easy to arrange the temperature detecting element on the back surface of the heat conducting plate. Further, by disposing a temperature detecting element on the back surface of the heat conducting plate, the temperature of the heating surface is directly detected, so that the temperature can be detected accurately without performing complicated calculations.

[0055]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1> §1. FIG. 1 is a schematic sectional view of a film heating type fixing device R to which the present invention is applied, and FIG. 2 is a schematic plan view of a heater provided in the fixing device R.

In FIG. 1, reference numeral 4 denotes an endless belt-shaped fixing film, H denotes a heating heater (ceramic heater) having a low heat capacity, and 10 denotes a support member for fixing and supporting the heater H and guiding the movement of the film 4 ( Heater holder). The film 4 is externally fitted to the assembly of the heater H and the support member 10 with a margin in the circumferential length.

A pressing roller 3 is rotatably supported, presses against the heater H via the film 4 and forms a pressing nip N. The pressing roller 3 is driven to rotate by driving means (not shown). The film 4 also functions as a driving roller for driving the film 4.

The film 4 is rotated at a predetermined peripheral speed by the rotation of the pressure roller 3 while sliding against the lower surface of the heater H in the clockwise direction of the arrow a in the figure. When the film 4 is driven to rotate and the heater H is heated to a predetermined temperature by energization, the fixing nip N
The recording material 1 on which the unfixed image T is formed is introduced between the film 4 and the pressure roller 3 by an image forming means (not shown), and the recording material 1 is brought into close contact with the outer peripheral surface of the film 4 to form a film. In the overlapping state, the unfixed toner image is passed through the fixing nip portion N, and the heat energy from the heater H is applied to the recording material 1 via the film 4 during the nip portion passing process. T is melted by heating. The recording material 1 that has been subjected to the fixing process passes through the film 4 after passing through the fixing nip.
And is discharged out of the device.

§2. Next, the heater H provided in the heat fixing device will be described in detail. FIG. 1B is a schematic cross-sectional view around the fixing nip portion.
FIG. 1C is a schematic plan view of the heater H on the side where a heating element is formed. In each drawing, members having the same numbers as those in FIGS. 9 and 10 indicate the same components.

In this embodiment, an AlN substrate (ceramic substrate) having a thickness of about 600 μm is used as the substrate 5 ′ as shown in FIG. 1C, and a 1 mm-wide resistor is provided at the center of the substrate so as to save the substrate width as much as possible. One heating element 8 is formed, and the AC electrode 1
A heat-generating substrate 6 ′ in which 1 is divided into right and left is used. The width of the substrate is 2 mm in front and back of the heating element 8 in accordance with the strictest regulation of the length of the insulated extending surface, so that the heating substrate is 5 mm in total.

The conventional heater (FIGS. 9 and 10)
In order to achieve a fixing speed of 16 sheets / min or more, the fixing nip N needs to be at least 6.5 mm or more. At a high speed of 24 sheets / min or more, it is desirable to secure a nip width of 8.5 mm or more even with a backside heating type AlN heater having high thermal conductivity, but the cost of the AlN substrate is at least that of the conventional alumina substrate. Because it takes more than twice,
A configuration having a substrate width of 8.5 mm or more leads to a significant cost increase.

Therefore, the heater of this embodiment is made of aluminum having substantially the same thermal conductivity while reducing the substrate width as much as possible and reducing the amount of substrate material used to less than half that of the conventional heater, thereby avoiding the cost increase. Material, nip width 8.5mm
As described above, a thickness of 50 μm having a plate width of 10 mm
Is brought into contact with the heat generating substrate 6 ′.

The heater H comprises a heating substrate 6 ′ and a heating plate 16.
Are fitted into the grooves 10a and 10b provided on the nip-facing surface side of the heater holder 10, respectively.
Is fixed to the heater holder 10.

In this embodiment, the substrate supporting portion 10 'is provided to have such a width as to act as a supporting member for guiding the side surface of the substrate, not the bonding surface of the substrate, and the mounting position (height) of the heat generating substrate 6'. Is determined by the thickness of the thermosetting adhesive 15 for bonding the heat generating substrate 6 ', and the height of the heating surface is also determined by fixing the heating plate 16 in a state in which the heating plate 16 is in contact therewith. At this time, the tolerance of the mounting position (height of the heating surface) of the heater H is widened to about 300 μm, but the depth of the groove 10b is so set that the surface of the heating plate protrudes outward from the surface of the heater holder no matter how the heater H is mounted. And the height of the heater support seat surface 10c are set. In the present embodiment, the heating plate 16
In the nip entrance and exit of the nip, a rounding process with a radius of 1 mm, sufficiently exceeding the tolerance of the mounting height accuracy of the substrate of 300 μm, is performed.
The fixing film 4 is provided by providing this curved surface.
Is prevented from being damaged by being rubbed by the edges of the heater holder 10 and the substrate 5, and the rubbing resistance acting on the fixing film 4 is reduced so that heating of the fixing film 4 such as paper wrinkles due to slipping or deformation of the film. It is possible to prevent deformation of the material.

Conventionally, a temperature detecting element (thermistor)
Was pressed against the substrate glass surface. In this example, in order to enhance the temperature control accuracy, the temperature detecting element 7 ″ was set to a temperature that is much higher in thermal responsiveness than glass and almost equal to the temperature of the fixing nip N. The heating plate 16 is pressed against the downstream side of the nip by using a thermistor pressing unit 13 composed of a coil, a leaf spring, a heat-resistant elastic body, etc. With this configuration, the nip during fixing is performed. The temperature change of the heating surface can be measured almost directly, and the temperature control can be performed more simply and more accurately than the conventional control method in which the fixing temperature is predicted and controlled from the number of sheets to be fixed and the temperature before the start of fixing.

In the above construction, since a silicone rubber-based adhesive is used as the thermosetting adhesive 15 so that the adhesive has a certain degree of elastic repulsion even after thermosetting, the heating substrate 6 ′ and the heating plate 16 Can be more reliably maintained. Further, in order to further ensure the contact between the heating substrate 6 'and the heating plate 16, the heating substrate 6' and the heater bonding seat surface 10 "are provided.
And a pressure means such as a heat-resistant elastic sheet may be interposed between them.

The material of the heating plate 16 is not necessarily aluminum, but other materials such as iron, copper, stainless steel, or alloys thereof may be used depending on the required cost, strength, and fixing performance. Needless to say, this may be done.

<Embodiment 2> FIG. 2 is a schematic sectional view of the vicinity of a fixing nip portion N according to a second embodiment of the present invention. In the figure, members having the same numbers as those in FIG. 1 indicate the same components. Further, this embodiment is different from the first embodiment in the configuration for mounting the heater H, and the other configurations are substantially the same.

In this embodiment, a heater unit is prepared in which a thin backside heating type AlN heater substrate (heating substrate) 6 ′ is bonded and fixed to a heat-resistant resin plate 10 ″ together with a thermistor 7 ″ via a heat insulating material 17 made of glass wool or the like. Then, the entire unit is configured to be pressed against the heating plate 16 inserted into the heater holder by using a heater unit pressing means 13 ′ composed of a coil, a leaf spring, a heat-resistant elastic body or the like. By using this configuration, the heating substrate 6 ′
The adjustment of the pressure contact force between the heating plate 16 and the heating plate 16 is facilitated, the degree of adhesion between them is increased, the thermal resistance of the contact portion is reduced, and the heating element 8
It is also possible to smooth the transfer of the heat generated in the nip side to the nip side, and to set the distribution of the pressing force in the longitudinal direction to suppress the warpage of the substrate based on the difference in the coefficient of thermal expansion when the temperature of the heater substrate rises Become. In addition, the provision of the highly heat-insulating member 17 on the glass coat surface side suppresses the transfer of heat to the glass coat surface side, thereby suppressing the amount of unnecessary heat leak to the non-heated area, and providing the heater holder 10 with heat resistance. It has become possible to use a member having low property and contribute to cost reduction.

It is needless to say that the heat insulating material 17 is not necessarily required when the heat-resistant resin plate 10 ″ has sufficient heat insulating properties in this configuration.

<Embodiment 3> FIG. 3 is a schematic cross-sectional view of the vicinity of a fixing nip portion N according to a third embodiment of the present invention.
2, the members having the same numbers as those in FIG. 2 indicate the same components. In addition, the present embodiment is compared with the above-described second embodiment,
The difference is that a slidability improving layer is provided on the heating surface, and the other configurations are the same.

In the present embodiment, a slidability improving layer 18 for improving the slidability of the fixing film 4 is provided on the surface of the heating plate 16 on the nip portion side. It is desirable from the viewpoint of high durability to use a diamond-like carbon layer having a high property to prevent abrasion of the surfaces of the rubbing members and improve the slidability, but a more inexpensive method is to release the surface of the fixing film. Al has the function of improving the abrasion resistance and improving the thermal conductivity of the entire film due to the high thermal conductivity in the fluororesin film used for the layer.
A fluorine resin layer in which a ceramic filler such as N or BN is dispersed may be used. In particular, the fine particles of BN are spherical and are more preferable as a material for forming the sliding surface.

By using this configuration, the slidability between the heating plate 16 and the fixing film 4 is improved, and the smooth conveyance of the fixing film 4 is ensured even if the width of the heating plate is increased in order to obtain a wider nip width. In addition, it is possible to prevent the occurrence of a problem such as a paper wrinkle or the like caused by the disturbed fixed image due to the slipping of the fixing film 4 or the slack of the film 4. It is no longer necessary to apply a lubricating agent such as heat-resistant grease that has been used to the heating surface, so that the number of assembling steps can be reduced and the manufacturing cost can be reduced.

<Embodiment 4> FIG. 4 is a schematic sectional view of the vicinity of a fixing nip portion according to a fourth embodiment of the present invention. In this figure, members having the same numbers as those in FIG. 3 indicate the same components. Further, points different from the third embodiment will be described below, and the same configuration will not be described again.

In this embodiment, as a method for forming the slidability improving layer, the entire fixing film is dipped in a fluororesin solution in which a BN filler is dispersed, so that the inner surface and the outer surface of the fixing film 4 'can be simultaneously coated. The dipping forming film 19 serving both as a release layer with improved thermal conductivity and a slidability improving layer is formed with a thickness of 10 μm both inside and outside, thereby streamlining the manufacturing process. For this reason, reduction of manufacturing cost becomes easy.

In this embodiment, a metal film having high thermal conductivity using Ni electroforming is used as the fixing film 4 'in order to further enhance the fixing characteristics.

Since the metal film 4 'is a film having a thickness of about 50 .mu.m with emphasis on durability, it is relatively strong and tends to cause minute floating to form a flat nip surface. Did not.

For this reason, in this embodiment, as the heating plate, the surface shape on the fixing film side has a high curvature at the entrance and exit of the nip so as to allow variation in the heater mounting position, and the center of the nip slides on the heating plate. Bottom cross-section heating plate 16 ′ having a bottom-shaped cross-section having a plurality of curvatures with a low curvature in order to suppress the curvature fluctuation of the moving fixing film 4.
Is used.

As a result, the adhesion between the metal film 4 and the bottom plate heating plate 16 'at the nip portion N is high, so that the film hardly floats, and the heat from the heat generating substrate 6' is efficiently transmitted to the fixing nip portion N. It has become.

As described above, according to this embodiment, the release layer and the slidability improving layer can be simultaneously formed on the inner surface and the outer surface of the fixing film 4 ′ by the dipping method. Thus, a fixing film 4 'having improved slidability is obtained.

Further, by optimizing the cross-sectional shape of the heating plate 16 ', the metal film 4' was effectively operated, and high fixing property was obtained.

<Embodiment 5> FIG. 5 is a sectional view showing the vicinity of a fixing nip portion according to a fifth embodiment of the present invention. 4, the members having the same numbers as those in FIG. 4 indicate the same components. The present embodiment is different from the above-described fourth embodiment in that a driven roller is provided for the heater holder, and the other configuration is the same.

The fixing film 4 ′ as in the fourth embodiment described above.
Is improved, the fixing film 4 'is attracted to the nip portion N, so that the surface of the heater holder and the fixing film 4' can easily come into contact with portions other than the heating plate. (Heating material transport direction)
The degree of friction between the surface of the heater holder on the upstream side and the fixing film 4 'increases. If the degree of rubbing of this portion is increased, the transport resistance of the fixing film 4 'is increased, which may cause the fixing film 4' to slip. For this reason, in the present embodiment, the driven roller 20 protruding from the surface of the heater holder is provided on the upstream side of the heater holder 10 to prevent the fixing film 4 ′ from coming into direct contact with the surface of the heater holder, and the conveyance of the fixing film ′. As a result, the fixing film 4 ′ is smoothly transported to the fixing nip N by the rotating rollers, so that problems due to slipping or sagging of the fixing film 4 ′ can be prevented.

<Embodiment 6> FIG. 6 is a front view of the vicinity of a fixing nip according to a sixth embodiment of the present invention. In the figure, members having the same numbers as those in FIGS. 1 and 2 indicate the same components, and the fixing film is omitted. In addition, the description of the same configuration as that of the first embodiment is omitted.

In the present embodiment, the inverted crown formed into a so-called inverted crown shape in which the heating plate to be brought into contact with the heat-generating substrate 6 'is thin at the center in the longitudinal direction and becomes thicker toward the left and right ends. A heating plate 16 "is used.

In this embodiment, the inverted crown heating plate 16 ″
Has a thickness of 50 μm at the center and 200 μm at both left and right ends, and provides a difference of 150 μm between the center and the end. By providing this shape, the pressure of the left and right end portions of the recording material (recording paper) passed through the fixing device becomes stronger than the central portion, and the entire recording material is conveyed while being pulled in the left and right direction. The slack of the recording material is eliminated, and the generation of wrinkles caused by the slack of the recording material at the time of fixing, which has been difficult with the conventional on-demand type fixing device, can be easily prevented.

<Example of Image Forming Apparatus> FIG. 7 is a schematic configuration diagram of an example of an image forming apparatus. The image forming apparatus of this embodiment is a copying machine or a printer using a transfer type electrophotographic process.

Reference numeral 31 denotes a rotating drum type electrophotographic photosensitive member, which is rotated at a predetermined process speed (peripheral speed) in a clockwise direction indicated by an arrow.

Reference numeral 32 denotes a contact charging roller as a photosensitive member charging means. A predetermined charging bias is applied to the contact charging roller 32. The surface of the rotating photosensitive member 31 is uniformly charged to a predetermined polarity and potential by the charging roller 32. You.

The charge-processed surface of the rotary photoreceptor 31 is exposed 33 with desired image information by an image information exposing means (not shown) such as a slit image exposing means for a document image and a laser beam scanning exposing means. Thus, an electrostatic latent image corresponding to the target image information is formed on the surface of the rotating photoconductor 31.

The latent image is developed by the toner developing device 34 as a toner image.

The toner image is transferred from a paper feed unit (not shown) to a transfer unit, which is a press-contact nip between the rotary photoreceptor 31 and the transfer roller 35 contacted with the transfer roller 35 and to which a predetermined transfer bias is applied. The image is transferred onto the transfer material 1 as the recording material conveyed at the timing.

The transfer material 1 having passed the transfer section and having received the transfer of the toner image is separated from the surface of the rotating photoreceptor 31, and
The film is conveyed and introduced into a heating device R of a film heating system as the image heating and fixing device shown in FIG.

After the transfer of the toner image to the transfer material 1, the surface of the rotary photoreceptor 31 is cleaned by the cleaning device 36 to remove the remaining deposits such as untransferred toner, and is repeatedly used for image formation.

<Others> The driving method of the film is not limited to the above-described embodiment, but may be the following. FIGS. 8A and 8B are schematic configuration diagrams each showing another type of apparatus.

The device (A) includes a heater H and a driving roller 4.
3. A fixing film 4 in the form of an endless belt is suspended and stretched between three members of a tension roller 44, and the driving roller 43 is driven by fixing driving means M to rotate the fixing film 4. . The pressure roller 3
Are driven by the rotational movement of the fixing film 4.

The device (B) uses a rolled long end film as the fixing film 4, and moves the film at a predetermined speed from a pay-out shaft 47 to a take-up shaft 48 via a heater H. That is, it is configured to be.

In the apparatus having such a configuration, the same effects as in the above embodiment can be obtained by controlling the fixing driving means M and the like according to the present invention.

[0100] The heating device of the present invention is not only a heating and fixing device of the embodiment, but also a device for heating a recording material carrying an image to improve the surface properties (such as gloss), a device for temporarily attaching, a drying process and a heat treatment. It can be widely used as a heating device such as a device for laminating.

[0101]

As described above, according to the present invention, good heating characteristics can be obtained, the speed of the apparatus can be increased, the temperature detection with high responsiveness suitable for speeding up, the degree of freedom in material selection can be increased, and the heater can be increased. A heater, a heating device, and an image forming apparatus capable of suppressing a load on a member that slides on the substrate.

[Brief description of the drawings]

FIG. 1A is a schematic cross-sectional view of an apparatus according to a first embodiment,
(B) is a cross-sectional view around the nip portion, and (C) is a plan model diagram of the heater.

FIG. 2 is a cross-sectional model diagram of the vicinity of a nip portion according to a second embodiment.

FIG. 3 is a cross-sectional model diagram around a nip portion according to a third embodiment.

FIG. 4 is a cross-sectional model diagram of the vicinity of a nip portion according to a fourth embodiment.

FIG. 5 is a cross-sectional model view of a nip portion and its periphery according to a fifth embodiment;

FIG. 6 is a cross-sectional model diagram around a nip portion according to a sixth embodiment.

FIG. 7 is a structural model diagram of an image forming apparatus.

FIG. 8 is an explanatory view of another film suspension method.

FIG. 9 is a diagram illustrating the configuration of a conventional heating device.

FIG. 10 is a configuration explanatory view of a conventional heating device.

FIG. 11 is an explanatory view around a nip portion when a mounting position of a heater is shifted.

FIG. 12 is an explanatory view around a nip when a metal film is used.

[Explanation of symbols]

 Reference Signs List 1 recording material 3 pressure roller (pressure member) 4 fixing film (film) 4 'fixing film (film: metal film) 5' AlN substrate (ceramic substrate) 6 'heat generating substrate 7 thermistor (temperature detecting element) 8 resistance heat generation Body 9 Glass protective layer 10 Heater holder (supporting member) 10 'Heater supporting portion 10 "Heat resistant resin plate 10a Heater substrate mounting groove 10b Heating plate 10c Heater supporting seating surface 11 Electrode 11' Temperature detecting electrode 11" Conducting through hole REFERENCE SIGNS LIST 12 through hole 13 pressure spring (elastic member) 14 back electrode 15 thermosetting adhesive 16 heating plate 16 ′ bottom heating plate 16 ″ inverted crown heating plate 17 heat insulating material 18 slidability improving layer 19 dipping forming film 20 driven roller H heater T toner image R fixing device (heating member)

Claims (26)

[Claims] 1. A heater characterized in that a heat generating substrate is brought into contact with a back surface of a heat conductive plate, at least a part of the surface of the heat conductive plate has a curved shape, and the surface of the heat conductive plate is used as a heating surface. 2. A heater characterized in that a heat generating substrate is brought into contact with a back surface of a heat conductive plate wider than the heat generating substrate, and the surface of the heat conductive plate is used as a heating surface. 3. A heat-generating substrate is brought into contact with the back surface of a heat-conducting plate wider than the heat-generating substrate, at least one of the heat-conducting plate surfaces in a width direction is curved, and the surface is used as a heating surface. A heater characterized in that: 4. A heater according to claim 2, wherein a temperature detecting means electrically independent from said heat generating substrate is provided on a back surface of said heat conducting plate. 5. The heater according to claim 1, wherein the heating substrate is formed by forming a resistance heating element that generates heat by energization on a ceramic substrate. 6. The heater according to claim 5, wherein the heat-generating substrate has a structure in which a substrate surface on which a resistance heating element is not formed is brought into contact with the heat-conducting plate. 7. The heater according to claim 5, wherein the ceramic substrate is an aluminum nitride substrate. 8. The heater according to claim 1, wherein the heat conductive plate has a thickness of 30 μm to 300 μm.
A press formed from a metal film having a thickness of 3 mm. 9. A press-contact nip portion formed by press-contacting the heater according to claim 1 with a support member of the heater and a heating surface of the heater directly or via an intervening member. A heating device, comprising: a pressure member; and applying heat from the heater to a material to be heated conveyed in the pressure contact nip portion. 10. The heater according to claim 1, a supporting member of the heater, a film moving in contact with a heating surface of the heater, and a heating member of the heater. And a pressure roller that forms a pressure contact nip by pressing the film through the film, and a heater is connected to the material to be heated conveyed between the film and the pressure roller of the pressure nip from the heater through the film. A heating device characterized by applying a heat of the above. 11. The heating device according to claim 10, wherein the film has an endless shape. 12. The heating device according to claim 10, wherein the film is a metal film. 13. The heating apparatus according to claim 10, wherein the film has a thickness of 20 to 100 μm, and a fluororesin release layer having a thickness of 10 to 30 μm is provided on the surface of the film. A heating device, characterized in that: 14. The heating device according to claim 10, wherein a slidability improving layer is provided between the film surface and the heat conductive plate heating surface. 15. The heating device according to claim 14, wherein a diamond-like carbon layer is provided on the heat conductive plate heating surface as the slidability improving layer. 16. The heating device according to claim 14, wherein the film has a resin layer formed on both sides of the metal film by a dipping method in which the metal film penetrates into a resin solution. A heating device characterized by using a release layer and the other as a slidability improving layer. 17. The apparatus according to claim 16, wherein the resin layer has a thermal conductivity and abrasion resistance improver dispersed in a mixed film of polytetrafluoroethylene and perfluoroalkoxytetrafluoroethylene copolymer. A heating device comprising: 18. The heating apparatus according to claim 17, wherein said thermal conductivity and wear resistance improving agent is a ceramic filler of alumina, aluminum nitride or boron nitride. 19. The heating device according to claim 10, wherein the film guide member, which also serves as the support member, is uniformly arranged in the longitudinal direction of the heating region on the upstream side of the press-contact nip portion in the film moving direction. A heating device comprising a driven roller in contact with a film. 20. The heating device according to claim 10, wherein the heat-generating substrate is fixed on a heat-resistant resin substrate via a heat insulating material, and the heat-resistant resin substrate is attached to the support member. And a heating device connected via an elastic member. 21. The heating device according to claim 9, wherein the heating surface of the heat conducting plate is thin at a central portion in a longitudinal direction of the heating surface, and the thickness increases toward both ends. A heating device having an inverted crown shape. 22. The heating device according to claim 9, wherein a width of the substrate in a direction of conveying the material to be heated is smaller than a width of the press-contact nip portion. 23. The heating device according to claim 9, wherein the heat conducting member has a curved surface on an upstream side and a downstream side in a conveying direction of the material to be heated. Characteristic heating device. 24. The heating device according to claim 9, wherein the heater is mounted such that a heating surface protrudes from a surface of the support member, and a boundary portion between the heating surface and the surface of the support member. Wherein the curved surface is provided over a range equal to or greater than the tolerance of the position of the heating surface at the time of attachment. 25. The heating device according to claim 9, wherein a temperature detecting element is provided downstream of the heat generating substrate on the back surface of the heat conductive member in the direction of conveying the material to be heated. Heating equipment. 26. An image forming apparatus comprising: an image forming means for forming an unfixed developer image on a recording material; and an image heating means for heating a recording material carrying the developer image. An image forming apparatus, wherein the heating unit is the heating device according to any one of claims 9 to 25.