JPH06314043A - Heating device and image forming device - Google Patents

Abstract

(57) [Abstract] [Objective] In a tension-free type film heating type heating device 7, a film 8 whose end is received by a flange member 13 and whose movement is restricted is broken, and wrinkles and cracks are generated. This prevents the film from running poorly and shortening its durable life, and in the image heating and fixing device, preventing the deterioration of the fixed image. [Structure] The lower limit of the second moment of area per constant cross-sectional area of the film 8 made of polyimide is I _G ≧ 2.
By defining the value as 49, the end limit strength of the film which rotates while the end part is regulated can be indicated by the second moment of area per 0.755 mm ² of the cross sectional area of the film. It became possible to design the film strength with the addition of a strength margin at the time, and it was possible to prevent the defective running and fixing property of the film which would occur due to the edges of the regulated film being broken or scratched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a heating body and a heat-resistant film whose inner surface is in close contact with the heating body and is slidably moved. The present invention relates to a heating device of a so-called film heating system, which conveys and passes the position of a heating body together and gives heat of the heating body to a material to be heated through a film.

More specifically, the film is a cylindrical endless thin film, which is rotatably driven in a state where its inner surface is in pressure contact with a heating element and at least part of its circumferential length is free of tension (tension). The present invention relates to a heating device of a type and an image forming apparatus including the heating device as an image heating and fixing device that heats and fixes an unfixed image on a recording material.

[0003]

2. Description of the Related Art A heating device of a film heating type is disclosed in, for example, JP-A-63-313182 and JP-A-2-1578.
No. 78 / Japanese Patent Laid-Open No. 4-44075 / No.
No. 204980, etc., such as copying machines, laser beam printers, facsimiles, microfilm reader printers, image display (display) devices, recording devices, etc., in image forming devices such as electrophotography, electrostatic recording, magnetic recording, etc. Directly on the surface of a recording material (electrofax sheet, electrostatic recording sheet, transfer material sheet, printing paper, etc.) as an image support by using a toner composed of a heat-meltable resin by an appropriate image forming process means Alternatively, an image heating stationary apparatus that heats and fixes an unfixed toner image (fixed image) corresponding to target image information formed by an indirect (transfer) method as a permanently fixed image on a recording material surface carrying the image. Can be used as

Further, it is not limited to the fixing device, and can be widely used as a means and a device for heat-treating a material to be heated, such as a device for heating a recording material carrying an image to modify its surface property, a device for hypothetical attachment, and the like. .

The film heating type heating device is compared with other known heating devices such as a heat roller type, a hot plate type, a belt heating type, a flash heating type and an open heating type, or an image heating and fixing device. ． Since a low-heat-capacity heater can be used as the heater and a thin-film heater with a low heat-capacity can be used, it is possible to save power and shorten the wait time (quick start), and suppress the temperature rise inside the unit. Can be done. The image heating and fixing device is advantageous in that it can prevent offset because the fixing point and the separation point can be set separately, and that it can solve various drawbacks of other types of devices.

FIG. 9 shows a schematic structure of an example of a film heating type heating device (image heating and fixing device) using an endless belt-shaped film as a heat resistant film.

31.32.14 are substantially parallel to each other.
The film suspension roller, the second film suspension roller, and the low heat capacity heater (ceramic heater) fixedly supported by the heat-resistant and heat-insulating heater support 34.

Reference numeral 35 is an endless belt-shaped thin heat-resistant film suspended between the three members 31, 32, and 14.

Reference numeral 36 is a pressure roller having a rubber elastic layer having a good releasability such as silicon rubber, which is pressed against the heating body 14 with a predetermined pressing force sandwiching the film 35.

The film 35 is rotationally driven in the clockwise direction a as indicated by the arrow by the frictional force between the first film suspension roller 31 and the inner surface of the film 35, using the first film suspension roller 31 as a film drive roller.

The heating element 14 is sandwiched by the film 35.
The recording material P to be image-fixed is introduced between the pressure roller 36 and the film 35 of the pressure contact nip portion (fixing nip portion) N formed by the pressure roller 36 and the pressure roller 36, and the fixing nip portion together with the film 35 is introduced. The heating element 14
Is applied to the recording material P via the film 35 to heat and fix the unfixed image T on the recording material P on the surface of the recording material P. The recording material P passing through the fixing nip portion N is the film 35.
Is separated from the surface and is transported.

In this type of device, since a strong tension acts on the entire circumference of the endless belt-shaped film 35 to drive it to rotate, the parallelism between the film suspension members 31, 32 and 14 and the film to be driven to rotate. The precision of parts of the pressure roller 36 and the heating body 14 that form the fixing nip portion N sandwiching 35, and the temperature distribution in the longitudinal direction of the heating body cause the moving force toward the film in the rotational driving process. That is, the film 35 is rotated in the direction a.
The force to shift along the length of the film suspension tension members 31, 32, and 14 in the direction perpendicular to (the film width direction) is strong, and a complicated control mechanism is required to control the shift, which increases cost. However, it was a factor of increasing the size of the device.

In the case of a device in which the first film suspension roller 31 is used as a driving roller to drive the film 35 by the frictional force between the inner surface of the film and the driving roller 31, while driving from the inner surface of the film, There is a problem that the sliding resistance between the heating body 14 and the inner surface of the film must be reduced.

Therefore, the applicant of the present invention has disclosed a tension-free type film heating type fixing device (heating device) in which the moving force toward the film is weakened, as disclosed in JP-A-4-44075-440.
No. 83, Japanese Unexamined Patent Publication No. 4-204980-204984 and the like.

FIG. 10 shows a schematic structure of an example of the apparatus. Reference numerals 10 and 10 'denote film inner surface guide members. A heating body fitting groove is provided along the length of the member at a substantially central portion of the outer lower surface of the member 10, and a low heat capacity linear heating body 14 is fitted in the groove. It's complicated and supported.

A cylindrical heat-resistant film 8 is loosely fitted over the film inner surface guide members 10 and 10 'with the heating body 14, and the film 8 is sandwiched between the heating body 14 and applied. The pressure roller 9 is in pressure contact.

The pressure roller 9 is used as a driving roller to be rotationally driven by a driving means M, and a friction force between the roller 9 and the outer surface of the film causes the cylindrical film 8 to heat the inner surface of the cylindrical film 8.
The inner surface of the film inner surface guide member 10, 10 'is rotationally driven in the clockwise direction a while sliding closely on the downward surface of the film 4.

In this film rotation driving state, the recording material P is introduced between the film 8 and the pressure roller 9 and passes through the fixing nip portion N, so that the recording material P is the same as in the apparatus of FIG. In the process of P passing through the fixing nip portion N, the heat of the heating body 14 is applied to the recording material P via the film 8 to heat-fix the unfixed image T.

In the case of the apparatus shown in FIG. 9 described above, a strong tension acts on the endless belt-shaped film 35 around the entire circumference during driving, but in the case of the apparatus shown in FIG. 10, the fixing nip portion N and the fixing nip portion are formed. The tension acts only on the film portion in the contact portion region between the film inner surface guide member outer surface on the upstream side of N in the film rotation direction and the film, and the tension does not act on most of the remaining film portion.

In such a tension-free type apparatus, the shift force of the film 8 when driving the film is smaller than that in the case of the apparatus shown in FIG. 9 described above, and the film shift control means or the film shift control means can be simplified. You can For example, the film shift control means may be as simple as the flange member 13 that receives the film end portion, and the film shift control means may be omitted to reduce the cost and size of the apparatus.

[0021]

However, even in the case of the tension-free type film heating type heating device as described above, depending on the film thickness and the material of the film 8, the flange member 13 receives the end portion and shifts to the side. The regulated film may be broken, and wrinkles and cracks may be generated, and there are problems such as poor running of the film and a reduction in durability life, and a fixed image in the image heating and fixing device.

The present invention aims to solve this problem.

[0023]

The present invention is a heating device and an image forming apparatus characterized by the following configurations.

(1) A fixed heating element, and a tubular endless thin film made of a polyimide material that is rotationally driven in a state in which the inner surface is in pressure contact with the heating element and at least part of the circumferential length is not tensioned. A support portion of the heating body, a film guide member having a guide portion that guides the inner surface of the film, and a rotary drive by being pressed against the heating body while sandwiching the film, and being rotated while being pressed against the heating body. And a flange member that receives and regulates the longitudinal end portion of the film, and the film misalignment angle determined by the peripheral length of the film guide member and the inner peripheral length and total length of the film is 0. 0.25 °
It is the above, the material to be heated is supplied between the film and the pressure rotating body of the pressure contact nip portion formed between the heating body and the pressure rotating body with the film sandwiched between the film and the film. It is a heating device that applies heat of a heating body to a material to be heated through a film by nip-conveying a pressure contact nip portion, and is a diagram parallel to the chord of the film cross-sectional shape where the cross-sectional area of the film is 0.755 mm ² . A heating device characterized in that the second moment of area I _G around the center is I _G ≧ 2.49.

(2) The product of the cross-sectional shape I _G and the film Young's modulus E of the film formed of any material is E · I _G ≧ 1245 [Kg / mm ² ] (1) ) The heating device described in. (3) The heating device according to (1) or (2), wherein the material to be heated is a recording material on which an image is to be fixed, and the image heating and fixing device heats and fixes an unfixed image on the recording material. .

(4) An image forming apparatus comprising the heating device according to any one of (1) to (3) as an image heating and fixing device for heating and fixing an unfixed image on a recording material. .

[0027]

According to the present invention, the lower limit of the second moment of area per constant cross-sectional area of a film made of polyimide is defined as I _G ≧ 2.49, which has been conventionally caused by the film deviation regulation. It is possible to prevent breakage, wrinkles and cracks of the film, deterioration of a fixed image, defective running of the fixing film, and reduction of durable life.

The limit strength of the end portion of the fixing film that rotates while the end portion is restricted is 0.755 m.
It can be shown by the moment of inertia of area per m ² . This made it possible to design the film strength with the added strength margin at the time of design. Therefore, it is possible to prevent the running failure and fixability of the fixing film, which are caused by the edge of the regulated film being broken or damaged.

[0029]

【Example】

<Embodiment 1> FIG. 1 shows a tensionless type film heating type heating device (image heating and fixing device) 7 according to the present invention.
2 is a cross-sectional side view, FIG. 3 is a plan view of a heating body with an intermediate portion omitted, and FIG. 4 is an exploded perspective view of the apparatus.

Reference numeral 10 designates a lower film inner surface guide member having a substantially semi-circular trough shape in transverse cross section, and 10 'designates an upper film inner surface guide member provided on the guide member 10 and having a substantially semi-arcuate upper surface. Is a linear heating element (heater) having a low heat capacity, which is attached to the outer lower surface of the lower film inner surface guide member along the length of the guide member, and 8 is the guide member 1.
A cylindrical heat-resistant endless thin film (fixing film) which is loosely fitted to 0 · 10 ′, 9 is a pressure roller that presses the heating body 14 with the film 8 interposed therebetween, and 13 and 13 are lower films. It is a pair of left and right flange members as a film regulating member which are fitted and supported by the protruding portions 10a, 10a at both longitudinal ends of the inner surface guide member 10, respectively.

The pressure roller 9 has both end shafts rotatably supported between bearings (not shown), and receives power from a drive system (not shown) to a gear 12 fixed to the shaft on one end side. It is driven to rotate counterclockwise.

11 · 11 is a pair of left and right flange members 13
Each of the outwardly projecting portions 13a, 13a of 13 and the immovable member 1
5 are compression springs respectively contracted between the heating body 14 and the pressure roller 9 with the pressure springs 11 and 11 sandwiching the film 8 and a predetermined contact pressure (for example, a total pressure of A4 width). Three
~ 6 Kg) in a pressed state.

The film 8 is a single layer film having heat resistance, toner releasability and toughness, or a composite layer film which has been subjected to a desired surface treatment or lamination treatment.

The film 8 of this embodiment is made of polyimide (P
I) A film, which is a heat-resistant single-layer film having a thickness of 30 μm, or a composite layer film further subjected to a release layer-providing treatment with tetrafluoroethylene (PTFE).

The heating body 14 is, for example, as shown in FIG. 3, an elongated substrate 14 made of alumina or the like having heat resistance, insulation, and good thermal conductivity whose longitudinal direction is perpendicular to the transport direction a of the film 8.
a, TaSiO ₂ , silver-palladium (Ag / Pd), Ta, which is formed by screen-printing linearly or in strips along the length of the substrate substantially at the center in the lateral direction on the surface side of the substrate.
₂ N, RuO ₂ , thin film heating resistor 14b such as nichrome,
The power supply electrodes 14c and 14c made of Ag or the like formed by screen printing or the like on both longitudinal ends of the resistor 14b, the overcoat layer 14d made of heat-resistant glass or the like for protecting the surface of the heater on which the resistor 14b is formed, the substrate It is a linear heating element having a low heat capacity as a whole and is composed of a temperature detecting element 14e such as a thermistor for detecting the temperature of the heating element provided on the back surface side.

The heating element 14 is fixedly supported by the film inner surface guide member 10 on the lower side with the surface side on which the resistor 14b is formed and provided facing downward, and both end electrodes 14c.
The resistor 14b generates heat over the entire length in the longitudinal direction due to power feeding between the 4c, and the temperature is raised.
detected by e, the detected temperature is a temperature control circuit (not shown)
Is fed back to and the energization to the resistor 14b is controlled so that the temperature of the heating body 14 is maintained at a predetermined fixing temperature.

When the pressure roller 9 is driven to rotate counterclockwise in FIG. 2, the cylindrical film 8 is brought into close contact with and slides on the surface of the heating body 14 by the surface frictional force of the pressure roller. It is rotationally driven in the clockwise direction a around 10.10 '. The guide members 10 and 10 'guide the inner surface of the film 8 over the entire longitudinal direction. Except for the fixing nip portion N, the rotating film 8 has no tension in its circumferential direction (tension free).

The film 8 is rotated by the rotation of the pressure roller 9, and the heating member 14 is heated to a predetermined temperature by energizing the resistor 14b. A recording material (transfer material) P having an unfixed toner image T on its upper surface as a heating member is introduced between the rotary film 8 and the rotary pressure roller 9 in the fixing nip portion N.

The recording material P introduced into the fixing nip portion N is in close contact with the outer surface of the rotating film 8 and is conveyed while sandwiching the fixing nip portion N together with the film 8 to transfer the heat of the heating body 14 through the film 8. The toner image T is applied and fixed by heating.

The lateral movement along the length of the film inner surface guide member during the rotation process of the film 8 is restricted by the end portion of the film being received by the inner surface of the flange member 13.

FIG. 5 shows a plane model diagram (model diagram) for explaining a state in which the fixing film 8 is displaced. When the fixing film 8 is offset, the positional accuracy of various members (particularly, the heating body 14 and the pressure roller 9) is not good, or the temperature distribution occurs in the longitudinal direction of the heating body. If not uniform and fixing film 8
This occurs when the accuracy of the single item (thickness, cylindricity, etc.) is not obtained, and the state of the end portion of the fixing film at that time is made uniform and takes the form shown in FIG.

That is, the fixing film transport force difference caused by the above-mentioned factors is caused by the difference (LL ') between the inner peripheral length L of the fixing film and the total peripheral length L'of the fixing film guide members 10 and 10'. Fixing film guide member,
Tilted β with respect to the flange member (offset angle).

In this embodiment, L ≧ L ′ ≧ 0.8L. The force (friction force) F perpendicular to the width direction of the pressure roller 9 causes the fixing film 8 to shift by a force of Fsin β = F · (L−L ′) / D D: total length of fixing film.

At this time, one point A on the circumference of the end portion 8a of the fixing film should draw a spiral locus as shown in FIG. 5 if the flange member 13 is not provided.
Due to 3, it looks as if it is rotating orthogonally to the fixing film guide member.

However, at the fixing nip portion N which gives the fixing film 8 a rotational force and a biasing force, the end portion of the fixing film is not subject to the shift restriction, and the locus thereof is fixed as shown in FIGS. 6 (a) and 6 (b). Changes greatly near the nip. Therefore, damage to the edges of the fixing film also occurs near the fixing nip.

The end portion of the fixing film is not restricted by the entire area as shown in FIG. 6, but is restricted by the buckling resistance of a part of the end surface.

The inventors of the present invention found the limit of the edge strength of the fixing film and the minute area at that time by the following experiments.

Deviation angle 0.25 ° Fixing film inner diameter φ24 Thickness 30μ Minute area 0.755 mm ² (Center angle 2π
/ 3) The proof strength (regulatory force) against the fixing film deviation force depends on the deviation angle and not on the fixing film inner diameter. Therefore, the regulated end area (small area) is constant regardless of the inner diameter of the fixing film.

FIG. 7 shows a schematic diagram of calculating the moment of inertia of area which is an index of the end face strength in this section.

The formula for calculating the second moment of area is given below.

[0051]

[Equation 1] The regulated portion I _Z is a strength index that best represents the magnitude of the buckling limit load given by P = π ² · E · I _Z / 4 / D ² D: fixing film total length.

The load P (Fsi
nβ) is constant, and the buckling of the thin fixing film occurs regardless of the total length D. Therefore, the limit strength of use of a fixing film that is rotationally driven without tension is represented by the product of the second moment of inertia I _Z and Young's modulus E. It will be done.

Further, the fixing film material base is polyimide, and its Young's modulus is much larger than the materials of the other layers of the fixing film and corresponds to the Young's modulus of the fixing film itself. Therefore, the Young's modulus of the fixing film can use the Young's modulus of polyimide (constant).

Therefore, the index of the strength that determines the use limit of the fixing film is the second moment of area I _Z given by the thickness, diameter and central angle of the fixing film in the regulated area.

In FIG. 7, the centroid G of the fan-shaped regulating surface is at a distance g from the central axis xx,

[0056]

[Equation 2] Respect as x-x sectional secondary moment parallel g over g axis to I _G is the second moment around the center axis I _X and the cross-sectional area A of the ^{_{centroid, I G = I X -g 2}} · Given by A. Therefore I _Z is

[0057]

[Equation 3] The above equation (1) is obtained, and if r ₁ is increased in a certain area, then I _Z
Decreases and I _z increases as r ₁ decreases. By substituting the diameter, the film thickness, and the regulated area obtained in the experiment for I _Z , the fixing film use limit strength index (second moment of area) I _Z can be obtained.

I _Z = 2.49 The following effects can be obtained by obtaining the above-mentioned usage limit index. The recording material P is passed from the heating body 14 through the fixing film 8.
In order to improve the efficiency of the heat applied to the fixing film 8, it is necessary to make the fixing film 8 thin while having a strength capable of withstanding a biasing force. Conventionally, the strength of this fixing film is 2
The following formula using the second moment as a representative value

[0059]

[Equation 4] Has increased the diameter.

However, according to the present invention, it is proved that increasing the diameter while keeping the regulated area constant is a decrease in strength. To reduce the thickness while maintaining the strength, the diameter should be decreased. It has been quantitatively proved that it is necessary to increase the second moment of area.

Therefore, it becomes possible to design parts with a clear margin with respect to the use limit, and there is no breakage, wrinkle, or tear at the regulation end portion of the fixing film 8.
Stable fixing film running and fixing properties were obtained.

On the contrary, when the outer diameter of the fixing film is increased due to the constitution of the main body, the fixing film thickness to be increased is calculated according to the use limit index. Therefore, in order to obtain a good fixing property, a simple design of how much the temperature of the heating element should be raised becomes possible.

Example 2 In Example 1, polyimide was used as the fixing film material, but it goes without saying that the fixing film can be formed of any heat resistant material.

In this case, the strength index of the fixing film is given by the product of the Young's modulus E'of the fixing film and the second moment of area. For example, when a heat resistant resin (PES) is used as the fixing film base material, the polyimide base fixing film strength limit is represented by E · I _Z = 500 (kg / mm ² ) · 2.49. = 200) fixing film similarly _{E'· I Z '= E ·} I represented by _Z I _Z' = 6.23 the specifications can be determined.

As described above, E · I _Z represents the original strength limit of the film, and when the fixing film material is PI (polyimide), E is a constant and the strength index is I _Z.
When another material is used (it is the base material of the film that contributes to the buckling resistance of the film and the release layer of the surface layer is not taken into consideration), E ′ and I _Z ′ of the other material are polyimide. If E · I _Z = E ′ · I _Z ′, there is no problem in strength. Therefore, the lower limit is E · I _Z ≧ 1245 for polyimide.

As described in the first and second embodiments above, the end limit strength of the fixing film 8 which rotates while the ends are restricted is determined by the second moment of area per 0.755 mm ² of the fixing film. Can be shown by.

As a result, the strength of the fixing film can be designed with the strength margin added at the time of design.

Therefore, it is possible to prevent the fixing film 8 from being broken or scratched at the regulated end portion thereof, which may cause a running defect and a fixing property of the fixing film.

<Third Embodiment> FIG. 8 shows a schematic structure of an example of an image forming apparatus incorporating an image heating and fixing device 7 as a film heating type heating device according to the present invention as shown in the first embodiment. Shows. The image forming apparatus of this embodiment is a reciprocating platen type, a rotary drum type, a transfer type, and a process cartridge attaching / detaching type electrophotographic copying apparatus.

Reference numeral 100 is an apparatus casing, 101 is a reciprocating type document placing table made of a transparent plate member such as a glass plate disposed on an upper surface plate 102 of the apparatus casing, and the apparatus casing upper plate 101
The upper part is driven to reciprocate to the right a and the left a'in the drawing at a predetermined speed.

Reference numeral G denotes an original, which is placed on the upper surface of the original placing table 101 according to a predetermined placing standard with the image surface side to be copied facing downward, and by placing the original pressure plate 103 on the original and pressing it. Set.

Reference numeral 104 denotes a slit opening serving as a document illuminating section, which is opened on the surface of the machine top plate 102 with the direction perpendicular to the reciprocating direction of the document placing table 101 (direction perpendicular to the paper surface) as the length.

The downward image surface of the document G placed and set on the document placing table 101 sequentially moves the slit openings 104 from the right side to the left side in the forward movement process of the document placing table 101 to the right a. The light L of the lamp 105 is passed through the slit opening 104 and the transparent original placing table 101 to be illuminated and scanned in the passing process, and the original surface reflected light of the illumination scanning light is reflected by the image element array 106 by the photosensitive drum. Image formation exposure is performed on the 107th surface.

The photosensitive drum 107 is coated with a photosensitive layer such as a zinc oxide photosensitive layer and an organic semiconductor photosensitive layer, and is rotated in a clockwise direction indicated by an arrow b at a predetermined peripheral speed around a central support shaft 108. During the rotation process, the charging device 109 receives a uniform positive or negative charging process, and the uniformly charged surface is subjected to the image formation exposure (slit exposure) of the original image, so that the surface of the photosensitive drum 107 is formed. An electrostatic latent image corresponding to the image-exposed original image is sequentially formed.

The electrostatic latent image is sequentially visualized by the developing device 110 with toner made of resin or the like that is softened and melted by heating, and the toner image as the visualized image is provided with a transfer discharger 111 as a transfer portion. It moves to the part.

Reference numeral S denotes a cassette in which transfer material sheets P as recording materials are stacked and housed, and the sheets P in the cassette are fed and fed one by one by the rotation of the feeding roller 112, and then the drum is rotated by the registration rollers 113. When the leading edge of the toner image forming portion on 107 reaches the portion of the transfer discharger 111, the leading edge of the transfer material sheet P also arrives at the position between the transfer discharger 111 and the photosensitive drum 107 so that they both coincide with each other. It is returned and is synchronously fed.

Then, the toner images on the side of the photosensitive drum 107 are sequentially transferred onto the surface of the feeding sheet P by the transfer discharger 111.

The sheet to which the toner image has been transferred at the transfer portion is sequentially separated from the surface of the photosensitive drum 107 by a separating means (not shown), and is guided to the fixing device 7 by the conveying device 114 to carry the unfixed toner. Receives heat fixing of the image,
An image formed product (copy) is discharged onto a paper discharge tray 117 outside the apparatus through a discharge roller 116.

The surface of the photosensitive drum 107 after the image transfer is subjected to removal of adhered contaminants such as transfer residual toner by the cleaning device 118, and is repeatedly used for image formation.

The PC is a process cartridge which is attached / detached to / from the cartridge attaching / detaching portion 120 in the apparatus main body 100.
In the case of the present example, the apparatus main body 10 including the four process devices of the photosensitive drum 107 as an image bearing member, the charging device 109, the developing device 110, and the cleaning device 118 together.
It is detachable and replaceable with respect to 0.

[0081]

As described above, according to the present invention, in a tension-free type film heating type heating device, a flange member receives an end portion thereof, and a film whose movement is restricted is broken, and wrinkles and cracks are generated. It is possible to prevent defective running of the film, reduction of the durable life, and deterioration of the fixed image in the image heating and fixing device.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a heating device (image heating and fixing device) according to a first embodiment.

[Figure 2] Cross-sectional side view

[Fig. 3] Plan view of the heating element with the middle part omitted and partially cut away

FIG. 4 is an exploded perspective view of the device.

FIG. 5 is a plane model diagram (model diagram) illustrating a state in which the fixing film has a deviation.

6A and 6B are detailed views of a fixing film end surface regulation portion.

FIG. 7 is an explanatory diagram of the formula for the moment of inertia of area in the regulated area.

FIG. 8 is a schematic configuration diagram of an example of an image forming apparatus.

FIG. 9 is a schematic configuration diagram of an example of a film heating type heating device.

FIG. 10 is a schematic configuration diagram of a device (tension-free type) having another configuration form.

[Explanation of symbols]

 7 General Reference Codes for Heating Device (Image Heating and Fixing Device) 8 Cylindrical Heat-Resistant Film (Fixing Film) 9 Pressure Roller 10/10 'Film Inner Surface Guide Member 13 Flange Member 14 Heater

Claims (4)

[Claims] 1. A fixed heating element, and a cylindrical endless thin film using a polyimide material that is rotationally driven in a state where the inner surface is in pressure contact with the heating element and at least part of the circumferential length is not tensioned, A support portion of the heating body, a film guide member having a guide portion that guides the inner surface of the film, and pressure-contact with the heating body with the film sandwiched between them to be rotationally driven, and the film is rotated while being in pressure-contact with the heating body. It has a pressure rotator and a flange member that receives and regulates the longitudinal end portion of the film, and the film offset angle determined by the peripheral length of the film guide member and the inner peripheral length and total length of the film is 0. The angle is 25 ° or more, and a pressure applied nip portion formed between the heating body and the pressure rotator sandwiching the film is applied between the film and the pressure rotator. A heating device for providing the material to be heated to heat the heating member via the film by causing clamping and conveying the piezoelectric contact nip supplying timber together with the film, as the film, the cross-sectional area becomes 0.755Mm ² A heating device characterized in that a second moment of area I _G about the centroid parallel to the chord of the film cross section is I _G ≧ 2.49. 2. The product of the cross-sectional shape I _G of the film formed of any material and the film Young's modulus E is E · I _G ≧ 1245 [Kg / mm ² ]. The heating device according to. 3. The heating according to claim 1, wherein the material to be heated is a recording material on which an image is to be fixed, and the image heating fixing device heats and fixes an unfixed image on the recording material. apparatus. 4. An image forming apparatus comprising the heating device according to any one of claims 1 to 3 as an image heating and fixing device for heating and fixing an unfixed image on a recording material.